Tesis: "RF Energy Harvesting"

1

Mattsson, Martin. "Differential Patch Antennafor RF Energy Harvesting". Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-200644.

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2

Zhang, Jingwei. "Rectennas for RF wireless energy harvesting". Thesis, University of Liverpool, 2013. http://livrepository.liverpool.ac.uk/18537/.

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There is an increasing interest in energy harvesting. The rectenna, which is a combination of a rectifier and an antenna, is a device to harvest wireless energy in the air. This thesis is concentrated on the analysis, design and measurement of compact rectennas for radio frequency (RF) wireless energy harvesting applications, and the thesis can be divided into three parts. The first part is about broadband planar dipole antennas with an unidirectional radiation pattern which is suitable for wireless energy harvesting applications. With the rapid development of various wireless systems, there is a need to have a broadband rectenna for energy collection. The antenna is optimized by changing the dipole shape, diameter, feed gap and the spacing between the antenna and the ground plane. It is shown the optimized antenna has a broad (from 2.8 to at least 12 GHz) with the ability to produce unidirectional radiation pattern. It is a good candidate to form a wideband dual-polarized antenna array for applications such as the wireless power transmission and collection. In addition, a simple rectenna and duel-polarized rectenna arrays are presented. The measurement of the rectenna array is shown that the design has produced the desired DC power with reasonable efficiency. The study is confirmed that the more elements in the array, the higher output voltage although the bandwidth is not as wide as expected because of practical limits. The second part is about a novel wideband cross dipole rectenna for RF wireless energy harvesting. The proposed device consists of a cross dipole antenna, low-pass filter (LPF) and voltage doubling rectifier circuit using Shottcky diodes as rectifying elements. It works over the frequency range from 1.7 to 3 GHz for the reflection coefficient less than -10 dB. Besides, the proposed rectenna can convert the RF energy into DC energy with a good conversion efficiency of up to 75% for high input power density levels (>5 mW/cm^2). In addition, another wideband rectenna built on FR4 substrate is optimized for low input power and the rectenna is optimized, built and measured. A further investigation for the input impedance of rectifier is also conducted. Experimental results demonstrate the rectenna has wideband rectification performance and the maximum rectenna conversion efficiency at 1.7 GHz is more than 50% for the power density of 0.1 mW/cm^2. The third part is about improving rectenna conversion efficiency for low input power density. Increasing the rectenna conversion efficiency for low power density is significant for improving rectenna performance. Currently, there are few of research focused on wideband rectenna arrays for low input power. A new wideband rectenna array with a reflector is developed to increase the rectenna conversion efficiency and output voltage through increasing the gain of the antenna. In addition, two connection methods are used to build the rectenna array and advantages and disadvantages for each method are presented. The RF to DC conversion efficiency of proposed rectenna arrays is much improved for low input power density over a wide bandwidth. This research has produced some important designs and results for wireless energy harvesting, especially in wideband rectennas, and is a solid step towards possible widespread applications of rectennas in the near future.

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3

Sanden, Erlend. "RF Energy Harversting : Design and implementation of an RF energy harvesting system for SoC". Thesis, Mittuniversitetet, Institutionen för elektronikkonstruktion, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-37659.

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This assignment was given by Nordic Semiconductor. In this project a radio frequency energy harvesting system able to harvest ambient power at 900 MHz (GSM) was simulated and designed. A Villard voltage multiplier, boost converter and power management circuit was implemented for the harvesting system. The intention was to implement a system which would give sufficient output power and voltage to supply a load (nRF52810) at all times. The nRF52810 is a power efficient multi protocol SoC made by Nordic Semiconductor. Since the power harvested by the antenna is of AC power, a recti er was needed. A Villard voltage multiplier was proposed as the most suitable application. It not only recti es the voltage, but the voltage doubles for every stage. A 2-stage Villard voltage multiplier was proposed with the advantage that in theory the output voltage should be four times higher in magnitude than the input voltage. There exists several other ways to boost a voltage, a voltage boost converter was combined with the Villard Voltage multiplier. According to calculations the boost converter should boost the voltage up to 2.3 V. Since the assumed power from the harvesting system may be lower than the power consumed by the load, a power managing circuit was also needed, which would avoid the load to drain the current from the storage element before the voltage level was sufficient. Different solutions for a power management circuit was proposed using different variations of MOSFETs. A real-life design was implemented, but the Villard voltage multiplier gave out a much lower e efficiency than expected from simulations. The output power of the VVM was too low to supply the load (nRF52810).

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4

Chaour, Issam, Ahmed Fakhfakh y Olfa Kanoun. "Enhanced Passive RF-DC Converter Circuit Efficiency for Low RF Energy Harvesting". Universitätsbibliothek Chemnitz, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-224264.

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For radio frequency energy transmission, the conversion efficiency of the receiver is decisive not only for reducing sending power, but also for enabling energy transmission over long and variable distances. In this contribution, we present a passive RF-DC converter for energy harvesting at ultra-low input power at 868 MHz. The novel converter consists of a reactive matching circuit and a combined voltage multiplier and rectifier. The stored energy in the input inductor and capacitance, during the negative wave, is conveyed to the output capacitance during the positive one. Although Dickson and Villard topologies have principally comparable efficiency for multi-stage voltage multipliers, the Dickson topology reaches a better efficiency within the novel ultra-low input power converter concept. At the output stage, a low-pass filter is introduced to reduce ripple at high frequencies in order to realize a stable DC signal. The proposed rectifier enables harvesting energy at even a low input power from −40 dBm for a resistive load of 50 kΩ. It realizes a significant improvement in comparison with state of the art solutions

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5

Khoury, Philip. "A Power-efficient Radio Frequency Energy-harvesting Circuit". Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/23627.

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This work aims to demonstrate the design and simulation of a Radio Frequency (RF) energy-harvesting circuit, from receiving antenna to the point of charge collection. The circuit employs a custom-designed antenna based around Koch fractal loops, selected for their small physical size, good multiband behaviour and ease of size scalability, as well as a power-efficient seven-element Greinacher rectification section designed to charge a super-capacitor or rechargeable battery for later use. Multiple frequency bands are tapped for energy and this aspect of the implementation was one on the main focus points. The bands targeted for harvesting in this thesis will be those that are the most readily available to the general Canadian population. These include Wi-Fi hotspots (and other 2.4GHz sources), as well as cellular (850MHz band), Personal Communications Services (1900MHz band) and WiMax (2.3GHz) network transmitters.

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6

Efthymakis, Panagiotis. "A RECTENNA FOR 5G ENERGY HARVESTING". VCU Scholars Compass, 2018. https://scholarscompass.vcu.edu/etd/5485.

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This thesis describes the design of a rectenna that is capable of operating in 5G. 5G’s availability will create the opportunity to harvest energy everywhere in the network’s coverage. This thesis investigates a Rectenna device with a new proposed topology in order to eliminate coupling between input and output lines and increase the rectification efficiency. Moreover, it is designed to charge a rechargeable battery of 3V, 1mA, with a 4.8mm diameter. The current design describes using one antenna for energy harvesting; this could be expanded to use an antenna array, which would increase the input power. This would lead to higher output currents, leading to the ability to efficiently charge a wide variety of batteries. Because of its small size, the rectenna could be used for the remote charging of an implantable sensor battery or for other applications where miniaturization is a design consideration.

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7

Fowler, Clayton M. "Application of Metamaterials to RF Energy Harvesting and Infrared Photodetection". Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/7024.

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Techniques for adapting metamaterials for the improvement of RF energy harvesting and infrared photodetection are demonstrated using experimental and computer simulation methods. Two methods for RF energy harvesting are experimentally demonstrated and supported by computer simulation. In the first method, a metamaterial perfect absorber (MPA) is made into a rectenna capable of harvesting RF energy and delivering power to a load by soldering Schottky diodes onto connected split ring resonator (SRR) structures composing the planar metasurface of the perfect absorber. The metamaterial rectenna is accompanied by a ground plane placed parallel to it, which forms a Fabry-Perot cavity between the metasurface and the ground plane. The Fabry-Perot cavity stores energy in the form of standing waves which is transferred to the SRR structures of the metasurface as AC currents that are rectified by the diodes to create DC power. This type of design enables highly efficient energy harvesting for low input power, creates a large antenna capture area, and uses elements with small electrical size, such that 100 uW of power (enough to operate simple devices) can be captured at ambient intensities ~ 1 - 2 uW/cm2. Two designs using this method are presented, one that operates for linear polarizations at 0.9 GHz and a smaller polarization-independent design that operates around 1.5 GHz. In the second method, the energy stored in the standing waves of an MPA Fabry-Perot cavity is instead harvested by placing a separate energy harvesting antenna within the cavity. The cavity shapes and enhances the incident electric field, and then the separate energy harvesting antenna is designed to be inserted into the cavity so that its shape and/or radiation pattern matches the electric field lines within the cavity and maximally extracts the stored energy. This method allows for great customization of antenna design parameters, such as operating frequency, polarization dependence, and directionality, by swapping out different metasurface and antenna designs. Using this method, the amount of power harvested by a simple dipole rectenna placed within a cavity is improved by a factor of 18 as compared to what it would harvest by itself at an ambient intensity of 35 nW/cm2. Lastly, the addition of plasmonic structures to DWELL (quantum dot-in-a-well) infrared photodetectors is investigated by computer simulation. DWELL photodetectors have the potential to one day replace standard mercury cadmium telluride detectors by being cheaper alternatives with a higher operating temperature. The inclusion of gold plasmonic structure arrays into DWELL detectors enables excitation of surface plasmon polariton modes that increase the responsivity of the detector to incident infrared radiation. The peak responsivity of a DWELL detector is demonstrated to improve by a factor of 8 for a 1 um thick layer of plasmonic structures and by a factor of 15 for a 2 um thick layer. These works are steps forward in making RF energy harvesting practically useful and for improving infrared photodetector performance.

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8

Elmorshedy, Lina. "RF energy harvesting in a decode-and-forward wireless relay network". Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/57607.

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Wireless communication has experienced tremendous growth over the past three decades. This led to the development of many novel technologies aimed at enhancing the system performance due to the limited availability of radio resources. Cooperative relaying is a promising technology which enhances transmission reliability using simple hardware. However, the extra power consumed for the process of information relaying may be an issue. Recent advances in wireless energy transfer have made it possible for self-sustainable relays that power themselves by capturing ambient energy wirelessly. In this thesis we focus on two technologies, namely, cooperative relaying which enhances the energy efficiency and reliability by allowing multi-hop communication with low power nodes, and Radio Frequency (RF) energy harvesting which obviates the need for a battery by capturing the ambient RF energy and using it as a source power. In the first part of the thesis, we study RF energy harvesting in a Decode-and-Forward (DF) Wireless Relay Network (WRN) in the presence of an interferer node. We consider the Time Switching Relaying (TSR) protocol, the Power Splitting Relaying (PSR) protocol and we propose a new hybrid TSR-PSR protocol. We derive expressions for the outage probability and throughput in the delay-sensitive transmission mode for the three relaying protocols, and compare their performances. For simplicity, we neglect the energy harvested from the interferer signal. In the second part, we study the general case in which we include the effect of harvesting energy from the interferer signal. Expressions for the outage probability and throughput in the delay-sensitive transmission mode are derived for the three relaying protocols. Numerical results are presented to illustrate the effect of including RF energy harvesting from the interferer. In the third part, we study shared and non-shared power allocation schemes for a two-hop DF WRN with multiple source-destination pairs. The pairs communicate via a single relay which harvests RF energy from the source transmissions in the presence of an interfering signal. The studied schemes are compared in terms of outage probability, throughput in the delay-sensitive transmission mode and fairness.
Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate

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9

Pinuela, Manuel. "Ambient RF energy harvesting and efficient DC-load inductive power transfer". Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/28090.

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This thesis analyses in detail the technology required for wireless power transfer via radio frequency (RF) ambient energy harvesting and an inductive power transfer system (IPT). Radio frequency harvesting circuits have been demonstrated for more than fifty years, but only a few have been able to harvest energy from freely available ambient (i.e. non-dedicated) RF sources. To explore the potential for ambient RF energy harvesting, a city-wide RF spectral survey was undertaken in London. Using the results from this survey, various harvesters were designed to cover four frequency bands from the largest RF contributors within the ultra-high frequency (0.3 to 3 GHz) part of the frequency spectrum. Prototypes were designed, fabricated and tested for each band and proved that approximately half of the London Underground stations were found to be suitable locations for harvesting ambient RF energy using the prototypes. Inductive Power Transfer systems for transmitting tens to hundreds of watts have been reported for almost a decade. Most of the work has concentrated on the optimization of the link efficiency and have not taken into account the efficiency of the driver and rectifier. Class-E amplifiers and rectifiers have been identified as ideal drivers for IPT applications, but their power handling capability at tens of MHz has been a crucial limiting factor, since the load and inductor characteristics are set by the requirements of the resonant inductive system. The frequency limitation of the driver restricts the unloaded Q-factor of the coils and thus the link efficiency. The system presented in this work alleviates the use of heavy and expensive field-shaping techniques by presenting an efficient IPT system capable of transmitting energy with high dc-to-load efficiencies at 6 MHz across a distance of 30 cm.

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10

Zhao, Ping [Verfasser], Manfred [Akademischer Betreuer] Glesner y Thilo [Akademischer Betreuer] Bein. "Energy Harvesting Techniques for Autonomous WSNs/RFID with a Focus on RF Energy Harvesting / Ping Zhao. Betreuer: Manfred Glesner ; Thilo Bein". Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2012. http://d-nb.info/1106117824/34.

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11

Song, C. "Broadband rectifying-antennas for ambient RF energy harvesting and wireless power transfer". Thesis, University of Liverpool, 2017. http://livrepository.liverpool.ac.uk/3008512/.

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Ambient wireless energy harvesting (AWEH), by means of capturing RF (radio frequency) and microwave energy from ambient and converting it to electric energy, has become an emerging technology and attracted an upsurge of research interests during the past five years. It could become a good addition to complement the existing energy harvesting technologies for such as vibration, solar and wind energies. One of the ultimate objectives of using these energy harvesting technologies is to create self-sustainable, truly standalone wireless sensor platforms and low power devices for smart home, smart cities and IoT applications, which will have a significant impact on our life in the future. However, the optimal design of a rectifying-antenna, or rectenna (as one of the vital devices for AWEH systems), is still very challenging. A number of key issues and research problems have been identified for broadband rectenna designs, such as the low conversion efficiency and strong nonlinearity under the ambient power conditions. The purpose of this thesis is to present a comprehensive study into broadband rectennas, aiming at overcoming the most challenging research problems of this topic. This thesis is comprised of three main research areas. The first area under investigation focuses on how to improve the overall power conversion efficiency of a broadband rectenna at ambient low power levels. In AWEH applications, a precise knowledge of ambient electromagnetic fields is essential. Therefore, a citywide electromagnetic field measurement campaign was conducted at Liverpool to identify the suitable frequency bands as well as the average power density at different ambient environments for AWEH. A novel broadband rectenna was designed and optimized at the ambient power levels obtained from the measurement campaign. Several novel techniques have been introduced to improve the overall conversion efficiency of the rectenna. Experimental results show that the harvested power and overall efficiency of this broadband rectenna are much higher than that of previously reported designs. This design confirms the feasibility of capturing RF energy from a typical indoor office environment for low power applications. The second area concentrates on how to reduce the nonlinear effect of broadband rectennas, since the performance of most existing rectennas can be significantly affected by the input power and load impedance variations due to this effect. Two designs are presented in this part. Page| xxi The first design is a novel six-band CP (circular-polarisation) rectenna using an improved impedance matching technique. A novel rectifier is introduced with a special matching network section to reduce the impedance mismatch caused by the load impedance variations. A miniaturized ultra-wideband CP receiving antenna is presented as well. Experimental results demonstrate that this design covers a wide frequency band (from 550 MHz to 2.5 GHz) and has constant conversion efficiency over a wide load impedance range (from 10 to 75 kΩ). The second design is an ultra-wide band rectenna using a hybrid resistance compression technique. The broadband matching network of this design is mixed with a resistance compression network to reduce the impedance variation of the rectifier. This design also demonstrates constantly high conversion efficiency and good impedance matching performance over a wide frequency band and load impedance range. The last area under investigation focuses on how to reduce the complexity of broadband rectennas. There are two designs presented in this part. In the first design, a cutting-edge technology to eliminate the need of an impedance matching network is introduced. A special broadband high impedance antenna is designed to conjugately match with the rectifier impedance directly. This design shows a very simple structure and design process. Experimental results demonstrate that this design without matching networks still achieves an excellent conversion efficiency, a good impedance matching performance and a reduced nonlinear effect. The second design is an adaptive rectenna with a wide band frequency-tunable feature. This design is also achieved without the need of impedance matching networks. The rectenna is configured with multiple output ports connected to a number of adaptive rectifier. Experiment results show that this design works well for a variety of frequencies, input powers and load impedance. Both designs show a much-simplified structure and reduced cost compared with other broadband rectenna designs. This thesis has successfully demonstrated a number of novel design methods for broadband rectennas. The most challenging issues such as the nonlinear effect and low conversion efficiency have been significantly overcome by using these presented technologies. The research and knowledge in this thesis should be of great significance to the future development of rectennas and have definitely increased the boundary of this topic to a new level.

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12

Olgun, Ugur. "Efficient Microwave Energy Harvesting Technology and its Applications". The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1348776239.

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13

Adegoke, Elijah. "Radio frequency channel characterization for energy harvesting in factory environments". Thesis, Loughborough University, 2018. https://dspace.lboro.ac.uk/2134/33412.

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This thesis presents ambient energy data obtained from a measurement campaign carried out at an automobile plant. At the automobile plant, ambient light, ambient temperature and ambient radio frequency were measured during the day time over two days. The measurement results showed that ambient light generated the highest DC power. For plant and operation managers at the automobile plant, the measurement data can be used in system design considerations for future energy harvesting wireless sensor nodes at the plant. In addition, wideband measurements obtained from a machine workshop are presented in this thesis. The power delay profile of the wireless channel was obtained by using a frequency domain channel sounding technique. The measurements were compared with an equivalent ray tracing model in order to validate the suitability of the commercial propagation software used in this work. Furthermore, a novel technique for mathematically recreating the time dispersion created by factory inventory in a radio frequency channel is discussed. As a wireless receiver design parameter, delay spread characterizes the amplitude and phase response of the radio channel. In wireless sensor devices, this becomes paramount, as it determines the complexity of the receiver. In reality, it is sometimes difficult to obtain full detail floor plans of factories for deterministic modelling or carry out spot measurements during building construction. As a result, radio provision may be suboptimal. The method presented in this thesis is based on 3-D fractal geometry. By employing the fractal overlaying algorithm presented, metallic objects can be placed on a floor plan so as to obtain similar radio frequency channel effects. The environment created using the fractal approach was used to estimate the amount of energy a harvesting device can accumulate in a University machine workshop space.

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14

Kokolia, Martin. "Nositelná rektifikační anténa pro RF sklízení energie". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2016. http://www.nusl.cz/ntk/nusl-241041.

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The aim of this thesis is to design and rectena that would be able to integrate into a cloth thanks to use of textile substrate. The first part deals with the possibilities of using various communication channels and services for maximizing the useable power. Attention is focused mainly on the use of textile materials for implementing microstrip circuits. It is made valorization of all the typical characteristics and problems using different fabrics as a microwave substrate and the possibilities of realization of conductive structures of microwave patch antenna and microstrip circuits. At the second part are identified parameters and constraints used for the design of the overall device with a rectifying antenna, which will be after the verification of the function in real implementation used for the final concept using textile structures. The design is verified by simulations by CST Microwave Studio and Microwave Designer. The initial design is being gradually extended by other concepts, the use of other materials and technologies. Several design are made, their properties evaluated and the best ones are then compared based on real measurements.

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15

Reed, Ryan Tyler. "Wireless Information and Power Transfer Methods for IoT Applications". Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/104146.

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As Internet of Things (IoT) technology continues to become more commonplace, demand for self-sustainable and low-power networking schemes has increased. Future IoT devices will require a ubiquitous energy source and will need to be capable of low power communication. RF energy can be harvested through ambient or dedicated RF sources to satisfy this energy demand. In addition, these RF signals can be modified to convey information. This thesis surveys a variety of RF energy harvesting methods. A new low complexity energy harvesting system (circuit and antenna) is proposed. Low power communication schemes are examined, and low complexity and efficient transmitter designs are developed that utilize RF backscattering, harmonics, and intermodulation products. These communication schemes operate with minimal power consumption and can be powered solely from harvested RF energy. The RF energy harvester and RF-powered transmitters designs are validated through simulation, prototyping, and measurements. The results are compared to the performance of state-of-the-art devices described in the literature.
Master of Science
Future devices are expected to feature high levels of interconnectivity and have long lifetimes. RF energy from dedicated power beacons or ambient sources, such as Wi-Fi, cellular, DTV, or radio stations can be used to power these devices allowing them to be battery-less. These devices that harvest the RF energy can use that energy to transmit information. This thesis develops various methods to harvest RF energy and use this energy to transmit information as efficiently as possible. The designs are verified through simulation and experimental results.

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16

Benassi, Francesca <1992&gt. "RF energy harvesting solutions for electromagnetic harsh environments: from industrial plants to wearable/implantable devices". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2022. http://amsdottorato.unibo.it/10370/1/Francesca_Benassi_tesi.pdf.

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The presented Thesis describes the design of RF-energy harvesting systems with applications on different environments, from the biomedical side to the industrial one, tackling the common thread problem which is the design of complete energy autonomous tags each of them with its dedicated purpose. This Thesis gathers a work of three years in the field of energy harvesting system design, a combination of full-wave electromagnetic designs to optimize not only the antenna performance but also to fulfill the requirements given by each case study such as dimensions, insensitivity from the surrounding environment, flexibility and compliance with regulations. The research activity has been based on the development of highly-demanded ideas and real-case necessities which are in line with the environment in which modern IoT applications can really make a positive contribution. The Thesis is organized as follows: the first application, described in Chapter 2, regards the design and experimental validations of a rotation-insensitive WPT system for implantable devices. Chapter 3 presents the design of a wearable energy autonomous detector to identify the presence of ethanol on the body surface. Chapter 4 describes investigations in the use of Bessel Beam launchers for creating a highly-focused energy harvesting link for wearable applications. Reduced dimensions, high focusing and decoupling from the human body are the key points to be addressed during the full-wave design and nonlinear optimization of the receiver antenna. Finally, Chapter 5 presents an energy autonomous system exploiting LoRa (Long Range) nodes for tracking trailers in industrial plants. The novelty behind this design lies on the aim of obtaining a perfectly scalable system that exploits not only EH basic operating system but embeds a seamless solution for collecting a certain amount of power that varies with respect the received power level on the antenna, without the need of additional off-the-shelf components.

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17

Zhang, Xiaohu. "VHF & UHF energy harvesting radio system physical and MAC layer considerations". Thesis, Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/1435.

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18

Papotto, Giuseppe. "Batteryless RF transceiver for wireless sensor networks". Doctoral thesis, Università di Catania, 2012. http://hdl.handle.net/10761/1082.

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Wireless sensor network (WSN) is a fast growing research area which has attracted considerable attentions both in industrial and academic environments in the last few years. In this work a complete RF transceiver for WSN applications is presented, which includes a RF energy harvesting system, a power management unit and a RF front end. The transceiver is able to operate by scavenging the required DC power from the incoming RF signal, thus avoiding the use of a battery. The use of a quartz oscillator has been avoided as well by exploiting the input signal as a frequency reference. This results in a highly integrated and low-cost transceiver solution. The circuit was designed in a 90-nm CMOS technology by TSMC. The device operates with a minimum input power of 15 dBm and supports a 915 MHz FSK downlink and a 2.45 GHz OOK uplink, which attain a data rate up to 5 and 10 Mbps, respectively.

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19

Ramezani, Parisa. "Extending Wireless Powered Communication Networks for Future Internet of Things". Thesis, The University of Sydney, 2017. http://hdl.handle.net/2123/16850.

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Energy limitation has always been a major concern for long-term operation of wireless networks. With today's exponential growth of wireless technologies and the rapid movement towards the so-called Internet of Things (IoT), the need for a reliable energy supply is more tangible than ever. Recently, energy harvesting has gained considerable attention in research communities as a sustainable solution for prolonging the lifetime of wireless networks. Beside conventional energy harvesting sources such as solar, wind, vibration, etc. harvesting energy from radio frequency (RF) signals has drawn significant research interest in recent years as a promising way to overcome the energy bottleneck. Lately, the integration of RF energy transfer with wireless communication networks has led to the emergence of an interesting research area, namely, wireless powered communication network (WPCN), where network users are powered by a hybrid access point (HAP) which transfers wireless energy to the users in addition to serving the functionalities of a conventional access point. The primary aim of this thesis is to extend the baseline model of WPCN to a dual-hop WPCN (DH-WPCN) in which a number of energy-limited relays are in charge of assisting the information exchange between energy-stable users and the HAP. Unlike most of the existing research in this area which has merely focused on designing methods and protocols for uplink communication, we study both uplink and downlink information transmission in the DH-WPCN. We investigate sum-throughput maximization problems in both directions and propose algorithms for optimizing the values of the related parameters. We also tackle the doubly near-far problem which occurs due to unequal distance of the relays from the HAP by proposing a fairness enhancement algorithm which guarantees throughput fairness among all users.

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20

LEONI, Alfiero. "CIRCUITI E SISTEMI DI ENERGY HARVESTING ELETTROMAGNETICO RF, TERMICO E BIOMECCANICO PER SENSORI AUTONOMI E DISPOSITIVI BIOMEDICI INDOSSABILI". Doctoral thesis, Università degli Studi dell'Aquila, 2020. http://hdl.handle.net/11697/148332.

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In recent years, the development of electronics and information technology can be considered among the protagonists of social growth and technological progress, now essential for everyday life. The growing number of applications that require global connectivity is going hand in hand with the increasing demand for portable devices, such as in the IoT (Internet of Things) environment, for the distributed monitoring of environmental parameters, the use of wearable devices for human well-being and health or for sports and leisure activities. These devices need a portable and long-lasting source of energy, reliable over time to guarantee prolonged self-sufficiency as much as possible. Historically, batteries have always been considered the only, indispensable energy source in applications for mobile devices, embedded systems, and remote systems; the use of batteries is, however, constraining for many factors, first of all, the limited capacity to supply energy over time, with consequent need for maintenance for replacement or recharging. Although great strides have recently been made on the development of ever more efficient batteries, both in terms of materials and process, and new electronic technologies are moving towards reducing consumption, to date the use of batteries is still limiting in terms of energy supply over time, for various portable applications. In this scenario, the activity of this dissertation focuses on the research and development of energy recovery systems from alternative sources, with reduced environmental impact, which can guarantee potentially unlimited autonomy for low-power portable devices, or standalone autonomous sensors, together with eco-sustainability. In particular, the research carried out focuses on the design and implementation of energy harvesting (EH) systems, single-source or multi-source, for the energy support of wearable devices in the biomedical field and for autonomous sensors used in wireless networks, for example for the widespread and distributed monitoring of the environment. After the introduction to the topic, a chapter dedicated to the review of the literature and the state of the art follows. This step is fundamental, as in any research activity, to identify the various existing techniques as well as the materials used for energy recovery and, moreover, it is fundamental to understand the current problems and limitations that require further analysis and in-depth studies. From this initial review, the main circuit blocks constituting the energy processing chain have been identified and analyzed. The literature review is followed by the author's contributions to RF electromagnetic, Thermoelectric and biomechanical energy harvesting. In particular, chapter 3 is focused on novel design methods for multi-antenna, multi-band and multi-channel power harvester for autonomous sensors and wearables, as well as practical considerations about matching network and antenna design for RF energy harvesting in the field of biomedical applications. Following, chapter 4 introduces the research works centered on thermoelectric and biomechanical energy harvesting. Specifically, the analysis and design methods of the human body’s heat thermoelectric energy harvesting are investigated ad discussed, as well as the possibility to recover the body motion energy by means of piezoelectric transducers. An example of a multisource energy harvesting system design is also presented and discussed. Finally, chapter 5 summarizes the findings and original contributions of this research. Suggestions for further work in this area are then given.

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21

Berges, Romain. "Dispositif conformable de récupération d'énergie radiofréquence : vers l'autonomie des objets communicants". Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0117/document.

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Parmi les principaux verrous à lever pour la mise en place de l’IoT, l’un des plus difficiles concerne l’autonomie des objets. Il est en effet difficilement concevable, vu le grand nombre de composants déployés, d’intervenir sur chacun pour remplacer, ou recharger, leur batterie. Dans ce contexte ma thèse a pour objectif de proposer des solutions éco-énergétique afin de rendre tout ou partie autonome des objets communicants, type capteur. Une des solutions est de développer des récupérateurs d’énergie radiofréquences fonctionnant aux fréquences dans la bande ISM, 900 MHz et/ou 2,4 GHz. Grâce aux modules de récupération d’énergie le capteur pourra fonctionner sur une période théoriquement illimitée, grâce à un module de stockage d’énergie embarqué rechargeable. En pratique, la fiabilité de l’élément de stockage définira le temps de vie du capteur, estimé à une vingtaine d’années avec les cellules de stockage rechargeables actuelles. Les solutions existantes dans le commerce sont presque exclusivement développées sur substrat époxy (ou dérivé). Cette solution est généralement robuste et performante. En revanche la rigidité mécanique du substrat réduit l’intégration des nœuds dans notre environnement, elle devient rédhibitoire dans le cas des réseaux corporels. Afin de permettre au capteur autonome de s’intégrer plus facilement, et d’adresser notamment des applications de type biomédicales, celui-ci sera développé sur substrat souple. Cet objectif pose certains défis quant à la maitrise des procédés de fabrication et de report des composants pour les performances des parties radiofréquences
Electronics has undergone an unquestionable evolution in recent years. The progress made gives more efficient circuits and smaller, but especially more and more energy efficient. This evolution, combined with advances in the digital and IT domain, has enabled the expansion of Internet of Things (IoT) applications based on the massive deployment of autonomous wireless communicating sensors. The first generations of sensor could only work during the time of discharge of their battery. One of the proposed ways to extend the autonomy of objects is to use the ambient energy. Several technologies have been developed to optimize the energy harvesting depending on the environment of the sensor. The work of this thesis allows developing RF energy harvesters in three steps. The first part studies antennas structures compatible with the energy harvesting. Each antenna is optimized to either recover more energy or better integrate into the environment. The second step focuses on the RF / DC conversion circuit. The study of different circuits architectures, diodes and number of stages potentially relevant for our application, allowed realising circuits able to work with our antennas. Each circuit was then optimized to increase its conversion efficiency and its sensitivity. The final step was to assemble an antenna with a rectifier to characterize the complete harvester according two different scenarios: opportunistic energy harvesting and energy transfer conditions

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22

Ababneh, Majdi M. "Design of Micro-Scale Energy Harvesting Systems for Low Power Applications Using Enhanced Power Management System". Scholar Commons, 2018. http://scholarcommons.usf.edu/etd/7117.

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The great innovations of the last century have ushered continuous progress in many areas of technology, especially in the form of miniaturization of electronic circuits. This progress shows a trend towards consistent decreases in power requirements due to miniaturization. According to the ITRS and industry leaders, such as Intel, the challenge of managing and providing power efficiency still persist as scaling down of devices continues. A variety of power sources can be used in order to provide power to low power applications. Few of these sources have favorable characteristics and can be designed to deliver maximum power such as the novel mini notched turbine used as a source in this work. The MiNT is a novel device that can be used as a feasible energy source when integrated into a system and evaluated for power delivery as investigated in this work. As part of this system, a maximum power point tracking system provides an applicable solution for capturing enhanced power delivery for an energy harvesting system. However, power efficiency and physical size are adversely affected by the characteristics and environment of many energy harvesting systems and must also be addressed. To address these issues, an analysis of mini notched turbine, a RF rectenna, and an enhanced maximum power point tracking system is presented and verified using simulations and measurements. Furthermore, mini notched energy harvesting system, RF rectenna energy harvesting system, and enhanced maximum power point tracking system are developed and experimental data analyzed. The enhanced maximum power point tracking system uses a resistor emulation technique and particle swarm optimization (PSO) to improve the power efficiency and reduce the physical size. This new innovative design improves the efficiency of optimized power management circuitry up to 7% compared to conventional power management circuits over a wide range of input power and range of emulated resistances, allowing more power to be harvested from small energy harvesting sources and delivering it to the load such as smart sensors. In addition, this is the first IC design to be implemented and tested for the patented mini notched turbine (MiNT) energy harvesting device. Another advantage of the enhanced power management system designed in this work is that the proposed approach can be utilized for extremely small energy sources and because of that the proposed work is valid for low emulated resistances. and systems with low load resistance Overall, through the successful completion of this work, various energy harvesting systems can have the ability to provide enhanced power management as the IC industry continues to progress toward miniaturization of devices and systems.

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23

Trovarello, Simone. "Selezione automatica di rettificatori a RF SIMO mediante autopolarizzazione di HEMT". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/21835/.

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Nella tesi viene proposto un sistema innovativo di Energy Harvesting per radiofrequenze a 2.45 GHz. Si tratta di un sistema single-input multiple-output ad ampissimo range dinamico di potenza in ingresso che sfrutta il fenomeno di autopolarizzazione di dispositivi non lineari come gli HEMT per selezionare autonomamente, e senza alcun controllo esterno, il ramo di rettificazione più adeguato al fine di ottenere la massima RF-to-DC conversion efficiency possibile. Inoltre il sistema garantisce il massimo isolamento fra i rami che compongono il circuito sfruttando l'ottimizzazione dei Large Signal S-Parameters dei singoli stadi del sistema.

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24

Vyas, Rushi J. "An embedded, wireless-energy-harvesting platform (E-WEHP) for powering sensors using existing, ambient, wireless signals present in the air". Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/52291.

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The objective of this research is to develop an embedded, wireless, energy-harvesting prototype (E-WEHP) that can power on and sustain embedded sensing functions using the power present in ambient wireless signals in urban areas. This research is part of a bigger effort towards greening RF circuits and applications in order to reduce their pollution foot-print. Pollution due to modern electronics is primarily caused by non-biodegradable packaging waste and batteries that form a big part of most electronics. Electronic waste can especially be a nuisance in RFID and wireless sensors that are mass-produced and widely-used in consumer items, buildings, industries, agriculture and transportation. The first part of this research effort addresses the issue of minimizing electronic packaging waste by characterizing and using biodegradable substrates such as Paper and Perfluoropolymer (PFA) as a dielectric material in RF circuits. Towards this goal, the first of its kind active wireless sensor modules made of biodegradable paper substrate using a clean and novel inkjet-printing technology is developed and successfully operated in the 900 MHz free ISM band. The second and third part of this research effort addresses the issue of battery waste by investigating the use of ambient solar and wireless radiation for powering RF and embedded electronics for wireless localization and sensing applications without the use of batteries. The second part of this work presents a unique solar-powered tag called SOLTAG that combines solar cells along with an RFID-type powering mechanism to implement a very low-cost, battery-less, semi-passive wireless-tag but with a much longer range than passive EPC-Gen2 RFID tags. A GPS-like, low-cost, vehicle-tracking system based on a received-signal-strength-indication method using SOLTAGs in vehicles and a wireless network of Mica-motes is successfully developed and tested with accuracy down to 1.62 meters The third and main part of this research work presents a novel embedded-wireless-energy-harvesting-prototype (E-WEHP) that can successfully power-on and sustain sensing and M2M peripherals in a 16-bit microcontroller using the power present in ambient, wireless, Digital-TV signals without the use of batteries. This work involves an in-depth characterization of OFDM signals used in Digital-TV broadcasts in Tokyo and Atlanta along with the design and development of the E-WEHP hardware and firmware that exploits the multi-carrier nature of such TV signals for powering itself at a range of over 6 km from the TV broadcast sources. This work opens up the possibility of pervasively powering sensor motes for applications such as environmental sensing, smart homes, structural health monitoring, security and internet of things without the environmental and logistical cost of periodic battery replacement and disposal.

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25

Soleiman, Andreas. "Battery-free Visible Light Sensing". Thesis, Uppsala universitet, Avdelningen för datorteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-381370.

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In this thesis, we show that it is possible to design a battery-free light sensing system that can sense and communicate hand gestures while operating fully on harvested power from indoor light. We present two main innovations that push our system to tens of microwatts of power to enable battery-free operation. First, we introduce a novel visible light sensing system that can track variations in light intensity by using a solar cell as a sensor. Solar cells are unlike photodiodes optimized for energy yield in the visible light region and hence do not require any power hungry active components such as an operational amplifier. Furthermore, solar cells can operate under more diverse light conditions as they are not susceptible to saturation under bright light. Second, we devise two ultra-low power communication mechanisms based on radio frequency backscatter to transmit sensor readings at various resolutions without the need of any energy-expensive computational blocks. We design two battery-free and self-powered hardware prototypes that are based on these two innovations. Our first design utilizes an on-board comparator based circuit to perform a 1-bit digitization of changes in light readings, consuming only sub-microwatt of power for digitization. For our second prototype, we design an analog backscatter mechanism that can map raw sensor readings directly to backscatter transmissions. We demonstrate the feasibility of our designs when sensing significant changes in light intensity caused by shadows from hand gestures, and reconstruct these at a receiving device. Our results demonstrate the ability to sense and communicate various hand gestures at a peak power of 20 microwatts when performing 1-bit digitization, and a mean power of 60 microwatts when performing analog backscatter. Both designs represent orders of magnitude improvement in terms of power consumption over state-of-the-art visible light sensing systems.
Battery-free Visible Light Sensing
MobiCom: G: Battery-free Visible Light Sensing

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26

Grante, Florian. "Récupération d'énergie électromagnétique pour alimenter des objets connectés à faible consommation". Electronic Thesis or Diss., Institut polytechnique de Paris, 2022. http://www.theses.fr/2022IPPAS022.

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Alors que l'IoT explose, ce manuscrit retranscrit les travaux de thèse réalisés dans le but de poser un regard sur la faisabilité de substituer les piles, source d'alimentation des objets connectés par les ondes WiFi dans la bande ISM à 2.4 GHz. Cette substitution représente aujourd'hui un enjeu de développement durable de l'IoT pour l'économie des ressources consommables que sont les piles. Alimenter l'intégralité de l'IoT avec des piles pourrait représenter jusqu'à 60 millions de tonnes (0.02%) d'émission de gaz à effet de serre chaque année.Il convient de définir les contraintes énergétiques du système qui serait uniquement alimenté par la récupération des ondes WiFi environnantes. Des mesures de consommation électrique d'un objet connecté mesurant la température, la pression et l'humidité et transmettant ces données via du Bluetooth Low Energy (BLE) sont réalisées et sont de l'ordre de 200 µJ. La seconde contrainte du système est la provenance de cette énergie, i.e. la puissance des ondes WiFi. Un protocole de mesure nous permet d'établir la puissance moyenne d'émission d'un routeur WiFi à partir d'un débit du réseau du routeur. Nous pourrons ainsi juger rapidement si un milieu est favorable ou non à ce type d'installation par simple mesure du débit.Nous avons ensuite mis en place le développement d'une rectenna (rectifying antenna) afin de convertir les ondes RF WiFi en tension continue DC, i.e. une source d'énergie utilisable par l'objet connecté. Au regard des campagnes de mesures que nous avons pu réaliser sur la puissance des signaux WiFi environnants, nous estimons que le système devra fonctionner avec des signaux de puissance de l'ordre de -20 dBm. Nous prenons donc le pari de concevoir une rectenna reposant sur un schéma très simple de redresseur mono alternance utilisant qu'une seule diode Schottky. L'état de l'art nous conforte dans l'idée qu'un schéma plus complexe entrainerait une chute de l'efficacité par la faiblesse du signal. Ce convertisseur, simulé et optimisé via le logiciel Keysight ADS, permet alors de mesurer des tensions DC allant jusqu'à 150 mV avec un signal incident RF d'une puissance de -20 dBm dans la bande ISM.Cependant, 1.8 V à 3.3 V sont nécessaires pour ce type de système. Nous avons alors recours à un élévateur de tension capable de fournir cette tension à partir d'une tension incidente de 20 mV. Néanmoins, un problème d'adaptation d'impédance avec notre convertisseur entraine une chute de tension trop importante. De plus, l'énergie récupérée en sortie du convertisseur étant trop faible pour initier instantanément l'élévation de tension, un stockage d'énergie intermédiaire est nécessaire. Nous mettons alors en place un circuit approprié pour la récupération d'énergie RF qui repose sur un super condensateur entouré d'interrupteurs. Nous pouvons tantôt isoler le super condensateur avec le convertisseur pour stocker l'énergie à une tension optimale, tantôt isoler ce super condensateur chargé à la bonne tension avec l'élévateur de tension. Il agit alors dans le second cas comme une source d'énergie et permet donc la conversion.Un banc de test réalisé avec des interrupteurs alimentés en externe montre le fonctionnement d'une telle architecture. Notre objet connecté est en mesure de transmettre ses données au moins une fois par heure en étant situé à 1 m de la borne WiFi ayant un trafic réseau de 25 Mbps.Cet ajout d'interrupteurs n'est pas sans créer de problème. Ils doivent être auto alimentés et capables de se déclencher sur une tension aussi faible qu'une centaine de millivolts. Nous étudions la conception de ces interrupteurs à partir d'un comparateur de tension à base de MOSFET. Au vu de la faible tension à surveiller, une étude du fonctionnement «shubthreshold» des MOSFET est réalisée pour établir une liste de paramètres permettant le fonctionnement du comparateur. Des futurs travaux concerneraient la possibilité de réaliser de tels interrupteurs, pour obtenir un système autonome
While the IoT is exploding, this manuscript transcribes the PhD thesis work done in order to look at the feasibility of substituting batteries, power source of connected objects by WiFi waves in the ISM band at 2.4 GHz. This substitution represents today a challenge of sustainable development of the IoT for the saving of consumable resources that are batteries. Powering the entire IoT with batteries could represent up to 60 million tons (0.02%) of greenhouse gas emissions each year.The energy constraints of the system that would be powered solely by harvesting the surrounding WiFi waves need to be defined. Measurements of power consumption of a connected object measuring temperature, pressure and humidity and transmitting these data via Bluetooth Low Energy (BLE) are carried out and are of the order of 200 µJ. The second constraint of the system is the source of this energy, i.e. the power of WiFi signals. A measurement protocol allows us to establish the average transmission power of a WiFi router from a network traffic flow of the router. We can thus quickly judge if an environment is favorable or not to this type of installation by simply measuring the network traffic.We then set up the development of a rectenna (rectifying antenna) in order to convert the WiFi RF waves into DC voltage, i.e. a source of energy usable by the connected object. Considering the measurements we have been able to make on the power of the surrounding WiFi signals, we estimate that the system will have to work with power signals of the order of -20 dBm. We therefore take the bet to design a rectenna based on a very simple schematic of a single-wave rectifier using only one Schottky diode. The state of the art confirms us in the idea that a more complex schematic would lead to a drop in efficiency by the weakness of the signal. This converter, simulated and optimized via the Keysight ADS software, can then measure DC voltages up to 150 mV with an incident RF signal of -20 dBm in the ISM band.However, 1.8 V to 3.3 V are required for this type of system. We then resort to a voltage booster capable of providing this voltage from an incident voltage of 20 mV. Nevertheless, an impedance matching problem with our converter leads to a too important voltage drop. Moreover, the energy harvested at the output of the converter being too weak to initiate instantaneously the rise in voltage, an intermediate energy storage is necessary. We then set up an appropriate circuit for RF energy harvesting, based on a super capacitor surrounded by switches. We can either isolate the super capacitor with the converter to store the energy at an optimal voltage, or isolate this super capacitor charged to the right voltage with the voltage booster. In the second case, it acts as a source of energy and thus allows the up-conversion.A test bench is realized with externally powered switches to show how such an architecture works. Our connected object is able to transmit its data at least once per hour while being located at 1 m from the WiFi terminal with a network traffic of 25 Mbps.This addition of switches is not without problems. They must be self-powered and capable of triggering on a voltage as low as a hundred millivolts. We study the design of these switches based on a MOSFET voltage comparator. In view of the low voltage to be monitored, a study of the "shubthreshold" operation of MOSFETs is carried out to establish a list of parameters allowing the operation of the comparator. Future works would concern the possibility of realizing such switches, to obtain an autonomous system

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27

Alessandrini, Marco. "Oscillatori elevatori di tensione per il recupero di micropotenze ambientali da sorgenti a radiofrequenza". Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/4893/.

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Nel presente elaborato è trattato l'innesco di un sistema di recupero ambientale di energia da sorgenti a radiofrequenza, captate tramite rectenna, nell'ambito di un sistema completamente autonomo dal punto di vista energetico, quindi non dotato di batteria ricaricabile interna. Dopo un'analisi dei problemi da affrontare e delle possibili soluzioni tecniche per gestire le micropotenze restituite dalla rectenna, ci si concentra in modo preferenziale sul ruolo del condensatore posto sulla porta d'ingresso dell'oscillatore di Meissner, che è utilizzato come elevatore di tensione per attivare gli stadi successivi. Sfruttando le esperienze con lo stesso oscillatore pilotato da altri sensori di energy harvesting, è possibile determinare approssimativamente se il circuito si presta o meno all'utilizzo con le rectenne nei campi RF, suggerendo eventuali migliorie da apportare per facilitarne il funzionamento.

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28

Haboubi, Walid. "Développements de circuits Rectennae bi-polarisation, bi-bande pour la récupération et conversion d’énergie électromagnétique à faible niveau". Thesis, Paris Est, 2014. http://www.theses.fr/2014PEST1089/document.

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L'amélioration de l'autonomie énergétique des systèmes communicants constitue aujourd'hui une des préoccupations majeures pour leur déploiement massif dans notre environnement. On souhaite rendre complètement autonome ces dispositifs électroniques (on pense entre autres aux capteurs et réseaux de capteurs) en s'affranchissant des sources d'énergie embarquées qui nécessitent des opérations de remplacement ou de recharge périodiques. Parmi les sources d'énergie disponibles qui peuvent être exploitées, on trouve les ondes électromagnétiques. Le dispositif qui permet de capter cette énergie et la convertir en puissance continue utile est dénommé Rectenna (Rectifying antenna) qui associe une antenne de captation à un circuit de rectification à base de diodes. Les rectennae ont fait l'objet d'un nombre important de communications dans la littérature ces dernières années avec pour fil conducteur, la recherche de performances optimales compte tenu de l'atténuation des ondes électromagnétiques et des faibles niveaux de champ récupérés. C'est dans ce contexte que s'est déroulé ce travail de thèse dont le financement a été assuré par un contrat ANR (REC-EM).Dans ce travail, on s'est attaché à développer, à concevoir et à caractériser expérimentalement des structures planaires qui présentent des propriétés intéressantes :- En terme de polarisations orthogonales, ceci de façon à s'affranchir de l'orientation arbitraire de l'onde incidente à la rectenna. Une rectenna à double polarisation circulaire à 2.45 GHz et à double accès sera réalisée pour, de plus, s'affranchir de la perte de 3 dB lorsque l'onde récupérée est à polarisation linéaire à orientation arbitraire.- En termes de résonances multiples, ceci pour augmenter le niveau de puissance récupérée par l'antenne et optimiser la puissance continue convertie. Une rectenna à double fréquence (1.8 et 2.45 GHz) et à accès unique sera conçue ainsi qu'une rectenna constituée d'un réseau de deux antennes double fréquence.- En terme de réduction de taille en s'affranchissant de l'utilisation du filtre HF entre l'antenne et le circuit de conversion ceci pour l'ensemble des structures rectennae développées dans ce travail. Dans tous les cas, il sera nécessaire de développer le circuit de rectification le plus adapté à la topologie de l'antenne de captation et évaluer la technique de recombinaison optimale coté DC pour s'affranchir au mieux des déséquilibres qui peuvent apparaître entre les voies d'accès de l'antenne. Pour contenir les dimensions de la structure globale, des circuits mono diode seront dimensionnés et réalisés pour chacune des structures. Enfin, on exploitera l'antenne à double polarisation circulaire double accès, dont on cherchera à diminuer les dimensions, pour alimenter un capteur de température à affichage LCD. Pour augmenter le niveau de tension nécessaire au fonctionnement du capteur, nous associerons entre la rectenna et le capteur un convertisseur DC-DC. Il s'agit, dans ce cas, d'un dispositif de gestion d'énergie adapté pour les faibles puissances. Deux convertisseurs seront employés dont celui développé par les laboratoires Ampère de l'Ecole Centrale de Lyon et SATIE à l'ENS Cachan. Ce convertisseur a fait l'objet d'une thèse également financée par l'ANR dans le cadre de ce contrat REC-EM
Improving energy autonomy of communication systems constitutes one of the major concerns for their massive deployment in our environment. We want to make these electronic devices (sensors and sensor networks) completely autonomous, avoiding the embedded energy sources that require replacement operations or periodic charging. Among the available energy sources that can be harvested, there are electromagnetic waves. The device that can capture this energy and convert it into useful DC power is called Rectenna (Rectifying antenna), combining antenna with diode-based rectifier. In recent few years, rectennas have reached a significant number of papers in the literature. The main challenge consists in improving performances in term of efficiency, in an attempt to overcome the electromagnetic wave attenuation and the low available field level. According to this context, this PhD work supported by the ANR project REC-EM has taken place. In this study, we have developed, designed and characterized planar structures that have interesting properties:- In term of orthogonal polarizations, so energy harvesting becomes feasable regardless the arbitrary orientation of the incident wave on the rectenna. A dual-circularly polarized rectenna at 2.45 GHz with dual-access will be set up to overcome the 3 dB power loss in the case of linearly-polarized incident wave with unknown orientation.- In term of multiple resonances, so the amount of total RF power collected by the antenna can be increased and consequently the converted DC power level can also be improved. A dual-frequency rectenna (1.8 and 2.45 GHz) with single access will be designed, as well as a rectenna based upon a dual-frequency antenna array.- In term of size compactness by avoiding the use of the HF filter between the antenna and the rectifier for all developed rectenna structures during this work. In all cases, it will be necessary to define the most suitable rectifier topology to each antenna and select, if it is appropriated, the optimum DC recombination technique to overcome the effects of RF power imbalance that may occur between the different antenna accesses. Besides, single-diode circuits will be designed and fulfilled for each structure. Finally, we will miniaturize the dual-circularly polarized dual-access antenna, and exploit it to power a LCD display temperature sensor. To enhance the DC voltage level required to activate the sensor, a DC-DC converter is inserted between the rectenna and the sensor. Such energy management device should be able to operate under low delivered DC power. Two converters will be used. The first one is developed by Ampere Lab at Ecole Centrale de Lyon and SATIE Lab at ENS Cachan. This converter was the subject of another dissertation also supported by the ANR under the REC-EM project

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29

Franciscatto, Bruno. "Conception et réalisation d'un nouveau transpondeur DSRC à faible consommation". Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENT037/document.

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Afin d'augmenter l'efficacité et la sécurité du trafic routier, de nouveaux concepts et technologies ont été développés depuis 1992 en Europe pour les applications RTTT (Road Traffic & Transport Telematics). Ces applications utilisent les équipements DSRC qui supportent les transmissions à courte distance à 5.8GHz. Vues la fiabilité et le succès de cette technologie, l'utilisation de ces équipements est ensuite étendue aux ETC (Electronic Toll Collection) ou Télépéage et aussi dans une multitude d'autres domaines d'application comme la gestion des flottes, le transport public et la gestion des parkings. Le système DSRC se compose d'un émetteur/récepteur (lecteur) et des transpondeurs (badges). En toute logique, l'approche industrielle oriente les développements vers la technologie de transpondeur semi passif qui, pour réémettre un signal utilise le signal transmis par l'émetteur–récepteur, effectue une modulation de phase d'une sous porteuse fréquentielle encodant ainsi les données à transmettre. Cette conception évite l'utilisation des oscillateurs locaux, comme dans les transpondeurs actifs, pour générer l'onde Radio Fréquence (RF). Ceci permet de produire des transpondeurs relativement à faible coût et de petite taille. Cependant ce concept nécessite quand même une batterie au Lithium pour assurer le fonctionnement du transpondeur pour une durée de 4 à 6 ans et ce malgré les progrès des technologies de circuits intégrés à faible consommation. Au fur et à mesure de l'expansion de ces équipements, il s'avère qu'avec les années la quantité des batteries au lithium à détruire deviendrait un problème crucial pour l'environnement. Aujourd'hui, la conception d'un transpondeur DSRC complètement autonome n'est pas faisable, car la quantité d'énergie nécessaire s'avère encore élevée (mode actif 8 mA/3.6 V). Néanmoins, la réduction de la consommation électrique du transpondeur, permet au moins doubler la durée de vie de la batterie et pourrait être un bon point de départ pour améliorer la protection de l'environnement.Dans cette thèse, nous proposons un nouveau transpondeur DSRC avec un diagramme d'état original qui réduit considérablement la consommation énergétique. Après validation d'un nouvel état de fonctionnement en mode très faible consommation d'énergie, nous avons étudié la possibilité de recharger la batterie du transpondeur à travers de la récupération d'énergie sans fil. Le bilan de liaison énergétique DSRC a été réalisé afin d'estimer la quantité d'énergie disponible quand une voiture avec un transpondeur passe à sous un système de péage. Toutefois, le bilan énergétique à 5.8 GHz présente une faible densité d'énergie RF, puisque la voiture ne reste pas assez sur le lobe de l'antenne DSRC afin de procéder à la récupération d'énergie. Par conséquent, nous avons alors exploré une autre fréquence ISM, le 2.45 GHz dans laquelle la présence d'émetteurs est bien plus grande. Dans le chapitre de récupération d'énergie sans fil nous présentons la conception et l'optimisation d'un nouveau récupérateur d'énergie RF. Après avoir démontré qu'une charge RF-DC optimale est nécessaire afin d'atteindre une haute efficacité de conversion RF-DC. Plusieurs redresseurs et rectennas ont été conçus pour valider les études numériques. Parmi, les résultats présentés dans cette thèse les rendement de conversion obtenus sont à l'état de l'art de la récupération d'énergie sans fil pour une très faible densité de puissance disponible
To increase the efficiency and safety of the road traffic, new concepts and technologies have been developed in Europe since 1992 for RTTT applications (Road Traffic & Transport Telematics). These applications use the Dedicated Short Range Communications (DSRC) devices at 5.8 GHz (ISM band). In view of the reliability and success of this technology, the use of such equipment is thus extended to the EFC (Electronic Fee Collection) or e-toll and also in many other application areas such as fleet management, public transport and parking management. Due to the broad applications, these equipments are subject to various standards CEN/TC 278, CEN ENV (EN) 12253, ETSI, etc.... The DSRC system consists in a transceiver (reader) and transponders (tags). Industrial approaches are oriented to semi-passive transponder technology, which uses the same signal sent by the reader to retransmit, performing a frequency shift and encoding data to be transmitted. This design avoids the use of the local oscillators to generate the RF wave, as in active transponders, and save electrical energy of batteries. This allows the development of relatively low cost and small size transponders. Despite advances in integrated low-power circuits technology, this concept still requires a lithium battery to operate the transponder for a period of 4-6 years. However, with the expansion of these facilities, it appears that over the years the amount of lithium to destroy has become a crucial problem for the environment. Nowadays designing a completely autonomous DSRC transponder is not feasible, since the amount of energy required is still high (8 mA/3.6 V active mode). Nevertheless, reducing the transponder electrical power consumption, as a solution to at least double the battery life, could be a good start point to improve environment protection.In this thesis we propose a new DSRC transponder with an original statechart that considerably reduces the power consumption. After validation of the new low-power consumption mode, we studied the possibility to recharge the battery of the transponder by means of Wireless Energy Harvesting. The DSRC Toll Collection RF link budget was carried out in order to estimate the amount of energy available when a car with a transponder passes through a toll system. However, RF link budget at 5.8 GHz presents a low power density, since the car does not stay enough on the DSRC antenna's field to proceed to energy harvesting. Therefore we explored another ISM frequency, the 2.45 GHz. Thus the Wireless Energy Harvesting chapter aims to further the state of the art through the design and optimization of a novel RF harvesting board design. We demonstrated that an optimum RF-DC load is required in order to achieve high RF-DC conversion efficiency. Several rectifiers and rectennas were prototyped in order to validate the numerical studies. Finally, the results obtained in this thesis are in the forefront of the State-of-the-Art of Wireless Energy Harvesting for very low available power density

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Al-Hraishawi, Hayder Abed Hussein. "DESIGN AND ANALYSIS OF COGNITIVE MASSIVE MIMO NETWORKS WITH UNDERLAY SPECTRUM SHARING". OpenSIUC, 2017. https://opensiuc.lib.siu.edu/dissertations/1412.

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Recently, massive multiple-input multiple-output (MIMO) systems have gained significant attention as a new network architecture to not only achieving unprecedented spectral and energy efficiencies, but also to alleviating propagation losses and inter-user/inter-cell interference. Therefore, massive MIMO has been identified as one of the key candidate technologies for the 5th generation wireless standard. This dissertation thus focuses on (1) developing a performance analysis framework for cognitive massive MIMO systems by investigating the uplink transmissions of multi-cell multi-user massive MIMO secondary systems, which are underlaid in multi-cell multi-user primary massive MIMO systems, with taking into consideration the detrimental effects of practical transmission impairments, (2) proposing a new wireless-powered underlay cognitive massive MIMO system model, as the secondary user nodes is empowered by the ability to efficiently harvest energy from the primary user transmissions, and then access and utilize the primary network spectrum for information transmission, and (3) developing a secure communication strategy for cognitive multi-user massive MIMO systems, where physical layer secure transmissions are provisioned for both primary and secondary systems by exploiting linear precoders and artificial noise (AN) generation in order to degrade the signal decodability at eavesdropper. The key design feature of the proposed cognitive systems is to leverage the spatial multiplexing strategies to serve a large number of spatially distributed user nodes by using very large numbers of antennas at the base-stations. Moreover, the fundamental performance metrics, the secondary transmit power constraints, which constitute the underlay secondary transmissions subject to a predefined primary interference temperature, and the achievable sum rates of the primary and secondary systems, are characterized under different antenna array configurations. Additionally, the detrimental impact of practical wireless transmission impairments on the performance of the aforementioned systems are quantified. The important insights obtained throughout these analyses can be used as benchmarks for designing practical cognitive spectrum sharing networks.

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31

Lopes, Hugo Filipe Texugo. "Sensores passivos para agricultura". Master's thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/18793.

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Mestrado em Engenharia Eletrónica e Telecomunicações
Esta dissertação surge no âmbito de uma parceria com a Associação de Criadores de Raça Marinhoa, com o objetivo de projetar e desenvolver um sistema de monitorização de gado em ambientes agrícolas. Este sistema tem sensores autónomos, não necessitam de troca de baterias durante anos, estando estes embebidos nos animais de forma a serem robustos e existir uma integração perfeita. Começou-se pelo desenvolvimento do firmware para comunicação dos rádios Texas CC1110, utilizando o protocolo SimpliciTI da Texas. Posteriormente programou-se com a plataforma Arduino o envio autónomo de dados via GSM obtidos pelo sistema GPS e pela comunicação via UART com o rádio CC1110. Por fim foi desenvolvido um sistema de Wake Up Radio e desenhou-se um módulo final com o sistema compacto a integrar no animal.
This Thesis comes under a partnership with the Associação de Criadores de Raça Marinhoa. The main purpose is development a livestock monitoring system in agricultural environments. This system has autonomous sensors, require no battery replacement for years, these being embedded in animals so as to be robust and there is a seamless integration. It started by the firmware development for communication of Texas CC1110 radios, using the SimpliciTI protocol of Texas. Later programmed with the Arduino platform autonomous sending data via GSM obtained by the GPS system and communication via UART with the CC1110 radio. Lastly it developed a Wake Up Radio system and drew up a final module with the compact system to be integrated in the animal.

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32

Vandelle, Erika. "Exploration de solutions antennaires et de formation passive de faisceaux pour la récupération et le transfert d’énergie sans fil". Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAT060.

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La récupération d’énergie électromagnétique provenant de sources ambiantes ou intentionnelles, de fréquences allant de 100 MHz à 10 GHz, est apparue ces dernières années comme une solution prometteuse pour développer l’électronique autoalimentée. Cependant, les faibles densités de puissance, généralement plus faibles que 1 μW.cm-2, engendrent de faibles efficacités de redressement et de faibles sensibilités, et la diversité des signaux ambients (direction d’arrivée et polarisation inconnues et variant dans le temps) ne permet pas d’utiliser des antennes directives.Dans cette thèse, les techniques de combinaison de la puissance RF ou DC dans des systèmes de récupération d’énergie à multiples antennes, associées à des structures originales, sont étudiées pour faire face aux différents verrous technologiques. De plus, une nouvelle Figure-de-Mérite, décrivant la capacité d’un système à récupérer de l’énergie ambiante, est développée avec des termes de probabilités représentant la diversité fréquentielle, spatiale et de polarisation des signaux ambiants.La première partie de cette thèse se consacre à la conception d’antennes et de rectennas individuelles efficaces. Des prototypes peu chers et recyclables sont proposés sur un substrat papier grâce à une technique originale de réduction des pertes.Dans la deuxième partie de cette thèse, l’efficacité de conversion RF-DC est améliorée à travers la combinaison de la puissance RF avant le processus de redressement, sans pour autant réduire la couverture spatiale du système. Pour cela, une structure 3D multidirectionnelle de réseaux d’antennes associés à des réseaux interférométriques passifs, pour la formation de faisceaux, est conçue, afin d’obtenir un diagramme de rayonnement multidirectionnel à fort gain. Cette solution inspirée des systèmes de radar et impliquant des matrices de Butler, aboutit à une haute efficacité de conversion RF-DC ainsi qu’à une couverture spatiale optimale. Ainsi, une capacité à récupérer de l’énergie plus grande que celles de l’état-de-l’art est obtenue.La dernière partie de cette thèse propose de remédier à la limite en sensibilité de la combinaison de puissance RF, plus faible qu’avec une combinaison DC en série de la puissance, grâce à un système reconfigurable. Pour cela, des cellules unitaires de rectennas sont conçues afin de former un réseau interférométrique adaptable et extensible, qui offre la possibilité d’obtenir un système hautement efficace et sensible à la fois. Cette solution peut servir à la récupération d’énergie, à la localisation passive et autonome ou à des applications RFID
Wireless energy harvesting (WEH) of ambient or intentional electromagnetic power sources of frequency ranging from 100 MHz to 10 GHz, has appeared as a promising solution to develop self-powered electronics in the past decades. However, the low power densities available, usually lower than 1 uW.cm-2, result in a limited RF-to-DC conversion efficiency and sensitivity of the energy harvesting system (rectenna) and the ambient signal diversities (unknown and time-varying direction of arrival, polarization) prohibit the use of directive antennas.In this thesis, the power combination techniques of Radio Frequency (RF) or Direct Current (DC) power in multi-antenna WEH systems, together with original structures, are investigated to address those challenges. Besides, a new Figure-of-Merit (harvesting capability) for rectennas operating in ambient scenarios is derived with probabilistic terms representing the frequency, polarization and spatial diversities of ambient signals.The first part of this thesis focuses on the design of efficient antenna and rectenna elements. Eco-responsible and low-cost prototypes are proposed by using a paper substrate along with an original strategy for the reduction of the losses.In the second part of this work, the rectification efficiency of a WEH system is enhanced through the combination of the RF power prior to the rectification process, without reduction of the spatial coverage. For this, a 3D multidirectional structure of scanning antenna arrays using passive beam-forming networks is designed to obtain a multidirectional high gain aggregate pattern. This radar-inspired solution involving Butler matrices results in a highly efficient RF-to-DC power conversion along with an optimal angular coverage, which leads to a harvesting capability higher than the state-of-the-art.The last part of this work addresses the limited sensitivity of the RF combination technique compared to that obtained with the series DC combination technique thanks to a reconfigurable system. To this end, modular rectenna unit cells are designed to form a scalable and adaptative interferometric beam-forming network, which offers the possibility to achieve a highly efficient and sensitive WEH system. This solution is suitable for low-power energy harvesting, autonomous passive tracking or RFID applications

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Bui, Do Hanh Ngan. "Antennes souples imprimables pour la récupération de champs électromagnétiques ambiants". Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAT062/document.

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L’Internet-of-Things désigne un développement en plein essor d’objets interconnectés et qui sont susceptibles de modifier nombre de services au sein de l’industrie comme pour la personne. Les développements actuels buttent sur plusieurs verrous dont celui de l’autonomie énergétique des objets ou encore des procédés de fabrication économiquement acceptables et respectueux de la planète. Dans ce contexte, la récupération d'énergie est une thématique largement répandue faisant appel à des sources très variées (mécanique, thermique, électromagnétique...). Cette thèse est notamment orientée vers la récupération d'énergie électromagnétique ambiante. Le second point caractéristique de cette thèse est de s'intéresser à des substrats souples et si possible recyclables. Le défi consiste à récupérer l’énergie provenant d’un champ électromagnétique ambiant extrêmement faible : ceci concerne l’antenne, qui doit par ailleurs répondre à une exigence de flexibilité pour son intégration future à un objet souple et déformable, et l’électronique de traitement de l’énergie.Le travail de thèse est articulé autour de trois phases principales :Dans la première phase, il s’agissait de l’étude des structures d’antennes compatibles en fréquence et en puissance reçue avec l’application de récupération d’énergie et une réalisation physique sur base souple (papier, tissu...). Cette phase a permis de présenter les différentes approches pour combiner les sources RF.Dans la deuxième phase, il s’agit de l’étude sur le rôle de circuits redresseurs dans le système de récupérer d’énergie. Les méthodes d'extraction des paramètres sont discutées en dissociant chaque élément et leurs rôles. De nombreuses mesures ont été réalisées afin de comparer différents modèles de la diode utilisée pour le redressement, en tenant compte également de l'impact réel du processus de fabrication et du processus de mesure.Une troisième phase permet l’optimisation de l’ensemble antenne et électronique (rectenna) pour divers scenarii et le suivi de la variabilité pour maintenir les pertes du système a minima. La réalisation de démonstrateurs pertinents, testés et caractérisés est présentée
Internet-of-Things means a growing development of interconnected objects that are likely to change many services within the industry as well as for the individual. Several barriers, including the energy autonomy of objects or production processes that are economically acceptable and respectful of the planet, hamper current developments. In this context, energy recovery is a widespread theme using a wide range of sources (mechanical, thermal, electromagnetic, etc.). This thesis is oriented towards the recovery of ambient electromagnetic energy. The second characteristic point of this thesis is to focus on flexible and, if possible, recyclable substrates. The challenge is to recover energy from an extremely low ambient electromagnetic field: this concerns the antenna, which must also meet a requirement for flexibility for its future integration with a flexible and deformable object, and the electronics of energy processing.The work of this thesis conducted in three phases.In the first phase, it was the study of the antenna structures compatible with frequency and power received with the energy harvesting application and a physical realization on flexible base (paper, textile, etc.). This phase allowed presenting the different approaches to combining the RF sources.In the second phase, the study on the role of rectifying circuit in the system of recovering wireless energy was presented. Methods for extracting parameters were discussed by separating each element and its roles. Numerous measurements have been conducted to compare different models of the diode, taking into account also the actual impact of the manufacturing process and the measurement process.A third phase allows the optimization of the antenna and electronic assembly (rectenna) for various scenarios and the monitoring of variability to keep the losses of the system at minima. The production of relevant demonstrators, test and characterization were presented

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34

Adami, Salah-Eddine. "Optimisation de la récupération d'énergie dans les applications de rectenna". Phd thesis, Ecole Centrale de Lyon, 2013. http://tel.archives-ouvertes.fr/tel-00967525.

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Les progrès réalisés durant ces dernières années dans le domaine de la microélectronique et notamment vis-à-vis de l'augmentation exponentielle de la densité d'intégration des composants et des systèmes a participé activement à l'apparition et au développement de systèmes portables communicants de plus en plus performants et polyvalents. La R&D dans les technologies de stockage d'énergie n'a pas suivi cette tendance d'évolution très rapide ; ce qui constitue un handicap majeur dans les évolutions futures des systèmes portables. La transmission d'énergie sans fils sur des distances considérables (plusieurs dizaines de mètres) grâce aux microondes constitue une solution très prometteuse pour pallier aux problèmes d'autonomie dans le cas des systèmes sans fils communicants. De plus, du fait de l'omniprésence des ondes électromagnétiques dans notre environnement avec des niveaux plus ou moins importants, la récupération et l'exploitation de cette énergie libre est également possible. La rectenna (Rectifying Antenna) est le dispositif permettant de capter et de convertir une onde électromagnétique en une tension continue. Plusieurs travaux de thèse axés sur l'étude et l'optimisation de la rectenna ont été réalisés au sein du laboratoire. Ces travaux avaient montré que pour des faibles niveaux de champs les tensions délivrées par la rectenna sont généralement très faibles et inexploitables. Aussi, comme la majorité des micro-sources d'énergie et à cause de son impédance interne, les performances de la rectenna dépendent fortement de sa charge de sortie. Ainsi, le développement d'un système d'interfaçage de la rectenna est nécessaire afin de pallier ces manquements inhérents du convertisseur RF/DC. Ce genre de système d'interfaçage est généralement absent dans la littérature à cause des faibles niveaux de puissance exploités. Par conséquent, la rectenna est très souvent utilisée tel quelle ; ce qui limite fortement le champ applicatif. Dans ce projet de recherche, un système de gestion énergétique de la rectenna complètement autonome a été conçu, développé et optimisé afin de garantir les performances optimales de la rectenna quelques soient les fluctuations de la puissance d'entrée et celles de la charge de sortie. Le circuit d'interfaçage permet également de fournir à la charge des niveaux de tension utilisables. Le système réalisé est basé tout d'abord sur l'utilisation d'un convertisseur DC/DC résonant pouvant fonctionner d'une manière complètement autonome à partir de niveaux très bas de la tension et de la puissance de la source. Ce convertisseur permet donc de garantir l'autonomie du système en éliminant la nécessité d'une source d'énergie auxiliaire. A cause de ses faibles performances énergétiques, ce convertisseur ne sera utilisé que durant la phase de démarrage. L'efficacité du système en termes de rendement énergétique et d'adaptation d'impédance est garantie grâce à l'utilisation d'un convertisseur Flyback fonctionnant dans son régime de conduction discontinu. Ainsi, une adaptation d'impédance très efficace est réalisée entre la rectenna et la charge de sortie. Ce convertisseur principal fonctionnera durant le régime permanent. Les deux convertisseurs ont été optimisés pour des niveaux de tension et de puissance aussi bas que quelques centaines de mV et quelques μW respectivement. Des mesures expérimentales réalisées sur plusieurs prototypes ont démontré le bon fonctionnement et les excellentes performances prédites par la procédure de conception ; ce qui nous permet de valider notre approche. De plus, les performances obtenues se distinguent parfaitement vis-à-vis de l'état de l'art. Enfin, en fonction de l'application désirée, plusieurs synoptiques d'association des deux structures sont proposés. Ceci inclut également la gestion énergétique de la charge de sortie.

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35

Boaventura, Alírio de Jesus Soares. "Efficient wireless power transfer and radio frequency identification systems". Doctoral thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/17374.

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Doutoramento em Engenharia Eletrotécnica
In the IoT context, where billions of connected objects are expected to be ubiquitously deployed worldwide, the frequent battery maintenance of ubiquitous wireless nodes is undesirable or even impossible. In these scenarios, passive-backscatter radios will certainly play a crucial role due to their low cost, low complexity and battery-free operation. However, as passive-backscatter devices are chiefly limited by the WPT link, its efficiency optimization has been a major research concern over the years, gaining even more emphasis in the IoT context. Wireless power transfer has traditionally been carried out using CW signals, and the efficiency improvement has commonly been achieved through circuit design optimization. This thesis explores a fundamentally different approach, in which the optimization is focused on the powering waveforms, rather than the circuits. It is demonstrated through theoretical analysis, simulations and measurements that, given their greater ability to overcome the built-in voltage of rectifying devices, high PAPR multi-sine (MS) signals are capable of more efficiently exciting energy harvesting circuits when compared to CWs. By using optimal MS signals to excite rectifying devices, remarkable RF-DC conversion efficiency gains of up to 15 dB with respect to CW signals were obtained. In order to show the effectiveness of this approach to improve the communication range of passive-backscatter systems, a MS front-end was integrated in a commercial RFID reader and a significant range extension of 25% was observed. Furthermore, a software-defined radio RFID reader, compliant with ISO18000-6C standard and with MS capability, was constructed from scratch. By interrogating passive RFID transponders with MS waveforms, a transponder sensitivity improvement higher than 3 dB was obtained for optimal MS signals. Since the amplification and transmission of high PAPR signals is critical, this work also proposes efficient MS transmitting architectures based on space power combining techniques. This thesis also addresses other not less important issues, namely self-jamming in passive RFID readers, which is the second limiting factor of passive-backscatter systems. A suitable self-jamming suppression scheme was first used for CW signals and then extended to MS signals, yielding a CW isolation up to 50 dB and a MS isolation up 60 dB. Finally, a battery-less remote control system was developed and integrated in a commercial TV device with the purpose of demonstrating a practical application of wireless power transfer and passive-backscatter concepts. This allowed battery-free control of four basic functionalities of the TV (CH+,CH-,VOL+,VOL-).
No contexto da internet das coisas (IoT), onde são esperados bilhões de objetos conectados espalhados pelo planeta de forma ubíqua, torna-se impraticável uma frequente manutenção e troca de baterias dos dispositivos sem fios ubíquos. Nestes cenários, os sistemas radio backscatter passivos terão um papel preponderante dado o seu baixo custo, baixa complexidade e não necessidade de baterias nos nós móveis. Uma vez que a transmissão de energia sem fios é o principal aspeto limitativo nestes sistemas, a sua otimização tem sido um tema central de investigação, ganhando ainda mais ênfase no contexto IoT. Tradicionalmente, a transferência de energia sem-fios é feita através de sinais CW e a maximização da eficiência é conseguida através da otimização dos circuitos recetores. Neste trabalho explora-se uma abordagem fundamentalmente diferente, em que a otimização foca-se nas formas de onda em vez dos circuitos. Demonstra-se, teoricamente e através de simulações e medidas que, devido à sua maior capacidade em superar a barreira de potencial intrínseca dos dispositivos retificadores, os sinais multi-seno (MS) de elevado PAPR são capazes de excitar os circuitos de colheita de energia de forma mais eficiente quando comparados com o sinal CW tradicional. Usando sinais MS ótimos em circuitos retificadores, foram verificadas experimentalmente melhorias de eficiência de conversão RF-DC notáveis de até 15 dB relativamente ao sinal CW. A fim de mostrar a eficácia desta abordagem na melhoria da distância de comunicação de sistemas backscatter passivos, integrou-se um front-end MS num leitor RFID comercial e observou-se um aumento significativo de 25% na distância de leitura. Além disso, desenvolveu-se de raiz um leitor RFID baseado em software rádio, compatível com o protocolo ISO18000-6C e capaz de gerar sinais MS, com os quais interrogou-se transponders passivos, obtendo-se ganhos de sensibilidade dos transponders maiores que 3 dB. Uma vez que a amplificação de sinais de elevado PAPR é uma operação crítica, propôs-se também novas arquiteturas eficientes de transmissão baseadas na combinação de sinais em espaço livre. Esta tese aborda também outros aspetos não menos importantes, como o self-jamming em leitores RFID passivos, tido como o segundo fator limitativo neste tipo de sistemas. Estudou-se técnicas de cancelamento de self-jamming CW e estendeu-se o conceito a sinais MS, tendo-se obtido isolamentos entre o transmissor e o recetor de até 50 dB no primeiro caso e de até 60 dB no segundo. Finalmente, com o objetivo de demonstrar uma aplicação prática dos conceitos de transmissão de energia sem fios e comunicação backscatter, desenvolveu-se um sistema de controlo remoto sem pilhas, cujo protótipo foi integrado num televisor comercial a fim de controlar quatro funcionalidades básicas (CH+,CH-,VOL+,VOL-).

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Andia, Vera Gianfranco. "Analyse et exploitation des non linéarités dans les systèmes RFID UHF passifs". Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENT052/document.

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Avec l'explosion de l'Internet des Objets (IoT), de nouveaux dispositifs permettant de tagguer les objets sont nécessaires afin de permettre non seulement leur identification mais aussi d'assurer des communications fiables et de nouvelles fonctionnalités comme la détection, la localisation ou la capture d'informations. Cette tendance s'appuie sur la technologie bien établie qu'est la radiofréquence par identification (RFID) et donc l'utilisation d'étiquettes (ou tags) faibles coûts et télé-alimentés. Dans ce contexte, de nombreux travaux au niveau de la couche d'application se tournent vers la mise au point de traitements logiciels complémentaires visant à produire de nouveaux types d'information. D'autres travaux visent à améliorer la couche physique avec l'objectif de miniaturiser encore le tag mais aussi de le doter de nouvelles capacités. Jusqu'à présent, il n'existe quasiment pas de travaux concernant la transmission du signal et aucun sur l'exploitation du comportement non-linéaire des puces RFID. Cette thèse vise à étudier les phénomènes non-linéaires produits lors d'une communication RFID.Dans la première partie, deux plateformes de mesure et de caractérisation spécifiques ont été développées : la première vise à observer les signaux au cours d'une communication RFID, et alors caractériser et analyser les effets liés aux phénomènes non linéaires ; la seconde permet d'effectuer différentes mesures directement sur les puces et les caractériser en termes d'impédance, production d'harmoniques et sensibilité. Ces plateformes ont permis : 1) de mettre en évidence que les fréquences harmoniques sont porteuses d'informations qui peuvent être exploitées et même offrir de nouvelles fonctionnalités ; 2) d'obtenir de nombreuses informations sur les propriétés des puces et d'en établir un modèle électrique précis ; 3) de déterminer des critères permettant d'évaluer la performance des tags dans le contexte étudié.Dans la deuxième partie, plusieurs nouveaux tags RFID ont été conçus, fabriqués, mesurés et évalués. Ces nouveaux tags fonctionnent non seulement dans la bande UHF mais aussi sont adaptés à la troisième harmonique dans la bande des microondes. Une méthodologie et des lignes directives d'aide à la conception de ce type de tags ont été établies et s'appuient sur les deux plateformes développées afin de caractériser les différents éléments. Dans un même temps, les effets liés à la fabrication ont aussi été étudiés et des études paramétriques ont permis de mettre en évidence l'effet sur les performances de la géométrie de l'antenne et du type de puce utilisée.Dans une troisième partie, les études se sont focalisées à exploiter les effets non-linéaires des dispositifs de redressement. L'idée générale est de coupler la RFID passive avec les dispositifs de transferts de puissance et de récupération d'énergie avec pour objectifs 1) de maximiser l'efficacité de conversion RF – continu 2) et d'augmenter la distance de lecture des tags passifs. Plusieurs prototypes ont été réalisés et leurs performances ont été démontrées.L'ensemble de ces travaux a mis en évidence un nouveau concept de communication RFID exploitant les non-linéarités générées par les puces RFID. Ce concept ouvre la voie à de nouvelles applications. et a fait l'objet d'une demande de brevet international
Powered by the exploding popularity of the Internet-of-Things (IoT), the demand for tagged devices with labels capable to ensure a reliable communication with added functions beyond the identification, such as sensing, location, health-care, among others, is growing rapidly. Certainly this growing is headed by the well-established Radio Frequency Identification (RFID) technology, and the use of wireless low-cost self-powered tags, in other words passive RFID tags, is the most widespread used alternative. In the constant evolution on this field, usually new software treatments are offered at the application layer with the objective to processing data to produce some new information. Further works aimed at improving the physical layer around the tag antenna miniaturization and matching techniques. So far, little or no work had been done on the exploitation of the communication channel, and certainly none has been done on the exploitation of the non-linear behavior of RFID chips.After presenting the RFID technology and phenomena produced by Radio Frequency (RF) non-linear devices, and leaning in some nearby works on the field, the core of this thesis starts by exposing two characterization platforms for the evaluation of non-linear phenomena presented during the reader-tag communication. One is specialized in radiating measurements considering the whole tag (antenna and chip) under test. The other is specialized in conducted measurements directly over RFID chips, allowing performing different parametric studies (power dependency, impedance, harmonic production, sensitivity). The characterization results show that harmonic signals generated from the passive RFID chip carry information.By exploiting the characterization results and to verify the hypothesis of exploitation of non-linearities in RFID, i.e. the use of harmonic signals, the research is pursued by designing, fabricating, and measuring four different configurations of RFID tags. The new RFID tags operate at the fundamental frequency in the UHF band and at its $3^{rd}$ harmonic in the microwave band. Antenna design policies, fabrication details, and parametric studies on the performance of the new prototypes are presented. The parametric study takes special care in the antenna structure, kind of chip used, received power, and read range.Finally, some alternatives approaches for the exploitation of non-linear effects generated by rectifying devices are presented. Some theoretical aspects and experimental results are discussed linking the passive RFID technology to the theories of Wireless Power Transfer (WPT) and Electromagnetic Energy Harvesting (EEH). The solution takes advantage of the non-linear nature of rectifying elements in order to maximize the RF-to-DC conversion efficiency of EEH devices and increase the read range of passive RFID tags. The solution triggers on the design of a RF multi-device system. The design procedure and tests consider three non-linear phenomena: (1) the impedance power dependency, (2) the harmonic production, and (3) the rectifying dependence on the RF waveform

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37

WANG, CHUNG-HO y 王中和. "RF Energy Harvesting System Design". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/s85v6z.

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碩士
國立勤益科技大學
電子工程系
107
In a wireless sensor network (WSN), an individuality battery is required for supporting its corresponding node among many separated sensor nodes to operate individually. How to supply a continuous power to sensor nodes is a key issue of WSN design. Therefore, energy harvesting techniques become increasingly important in solving WSN power supply issue or enhance the battery life cycle. The work focus on building energy harvesting system by using different RF antenna structures along with rectifier and storage for two different radio frequency of 915MHz and 2.4GHz applications. The experiment environment record the data of harvesting vs. distance under the radio source power 20dBm with frequency at 915MHz and 2.4GHz . The collector's storage capacitor is charged at a distance of 50cm. The capacitor voltage can reach 1.66v and the system efficiency is about 4.74%. The stored energy estimate can be supplied to the WSN sensor with a working voltage of 1.2V and power consumption of 1mW up to 182 seconds.

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38

Chen, Yi-Ping y 陳毅平. "Rectifier Design for RF Energy Harvesting". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/72690772754741227168.

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碩士
國立勤益科技大學
電子工程系
102
Wireless Sensor Network (WSN) is composed of many distributed sensors with requirement of self-powering through the use of energy harvesting techniques. In this thesis, charge pump is used to design rectifier for radio frequency (RF) energy harvesting. Both the voltage attenuation and dead zone problems will be discussed that are occurred when traditional charge pump used in RF energy harvesting systems. The differences of the charge pump design individually based on Normal-Vth, Low-Vth and Zero-Vth transistors are analyzed. A compensation approach is proposed to solve these problems and to balance between the compensation voltage and leakage current. By using this approach, a new rectifier denoted as NRT5S5 is proposed for radio frequency (RF) energy harvesting applications. Based on TSMC 0.18μm CMOS 1P6M 1.8 &; 3.3V process and RF input signal frequency at 900MHz, the NRT5S5 rectifier has conversion efficiency up to 31.73% and the output voltage of 2.002V, both with the condition of input power to be -12dBm. The experiments show that our design is valid and work.

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39

Huang, Jhuang-Dian y 黃莊典. "Rectifier Design for RF Energy Harvesting Systems". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/41952226343587996449.

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碩士
國立勤益科技大學
電子工程系
101
In a wireless sensor network (WSN), sensors are distributed in a field to monitor environmental variables such as temperature, sound, vibration, pressure, and so on. Then, these data are transmitted over the network to the base stations. WSNs require sensor nodes which must be small, with simple structure and low cost. It also needs long-distance communication technique to obtain a variety of information and to minimize the number of base stations. How to supply a continuous power to sensor nodes is a key issue of WSN design. Therefore, energy harvesting techniques become increasingly important in solving WSN power supply issue. In the RF energy harvesting systems, rectifier plays the potential role to perform two major tasks including rectifying RF signal and boosting the rectified voltage. By using the charge pump is a very appropriate way to boost the rectified voltage. This thesis focuses on the voltage attenuation and dead zone problems of a traditional charge pump used in energy harvesting systems. The compensation is used to solve these problems, and balance between the compensation voltage and leakage current in design is also under consideration. The proposed new rectifier for RF energy harvesting system is designed by using TSMC 0.18μm CMOS 1P6M 1.8 &; 3.3V process. The input signal frequency is assumed as 900MHz. The experimental results show that the conversion efficiency can be up to 42.25% and the minimum incident power is -12.66dBm.

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40

Kuo, Chen-Yi y 郭鎮億. "Wide Input-Range RF Energy Harvesting System". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/a9th37.

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碩士
國立交通大學
電機工程學系
107
With the blossom of the Internet of Things (IoT) in recent years, the demand of wireless sensors increases rapidly. Conventionally, these sensor nodes are powered by chemical batteries, which usually have a limited lifetime and large size/volume. RF wireless powering technology provides an alternative way to extend the battery lifetime or to supply the low-power sensor nodes without battery. However, to realize a high-efficiency power conversion system for wide-range RF energy harvesting is still a big challenge due to the tradeoffs between the sensitivity and power conversion efficiency (PCE). A new high-efficiency and wide-dynamic-range wireless energy harvesting system, composed of a reconfigurable power-aware RF/DC conversion chip and a high-gain reader antenna with air gap tunability, is proposed in this thesis. The proposed RF/DC conversion chip utilizes a reconfigurable architecture to extend the high-efficiency range over a varying input power and load current. The low dropout regulator (LDO) following the rectifier provides a stable supply voltage. The PCE of the rectifier is affected by the output load, so a current/frequency converter (C2F) is employed to convert the load current to a corresponding frequency, which modulates a switched-capacitor load at the output of the rectifier. With this mechanism, the load effect can be compensated and thus maintain the PCE of the rectifier over a wide load range. Moreover, an energy saving mechanism is proposed to store the energy at small load current and to use the energy when the input power is insufficient to supply the system. The proposed RF/DC conversion chip, implemented using 65nm CMOS technology, achieves a peak PCE of 70.5% at a 11kΩ load and a wide RF input range larger than 15dB for at least 20% PCE. The reader antenna consists of 4x1 array elements to concentrate the radiation pattern and to increase the antenna gain. The air gap technique is used to reduce the effective dielectric constant and to enhance the radiation efficiency. The tunable air gap adjusts the center frequency of the antenna to meet the required specifications in different countries. The proposed reader antenna has a peak gain of 12dBi and the minimum |S11| at 915MHz is -24.5dB. The designed system with high-PCE energy harvesting chip and high gain antenna can solve the problem of short communication distance and enable large numbers of power-and-size-constrained IoT applications, such as bio-implants, smart sensing devices, and mobile electronic tolling collection tags.

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41

Kaddi, P. "Analog Front End for RF Energy Harvesting". Thesis, 2014. http://raiith.iith.ac.in/118/1/EE11M10.pdf.

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This thesis proposes a design for ultra low power sensitive single and dual band RF energy harvesting system for UHF microwave frequencies at 2.4-GHz and 865-MHz to 960- MHz(ISM band). The system is designed to power a load and generate a constant 1-V output voltage for a battery-less passive energy harvesting circuit. Input power is fed from 50 RF source to emulate antenna at UHF microwave band. The design includes single band and dual band off-chip RF matching circuit, RF limiter, Differential Rectifier, Power On Reset (POR), Band Gap Reference (BGR) and Low Drop Out Regulator (LDO). The number of rectifier stages is optimized to obtain a better efficiency to generate 1V output voltage. The full system performance has been verified by simulations for equivalent received power from -20-dBm to -10-dBm. The overall RF energy harvesting system efficiency at -14-dBm (10 m Distance from 4W EIRP source) input power for single band matching at 2.4-GHz is 46.9% with 54Kohm load and for dual band matching at 953-MHz and 2.4-GHz we achieve an efficiency of 41.5% with 61K ohm load and 46% with load 54.4Kohm respectively. The technology node employed is 0.18_m technology. The simulations are carried out at schematic level with bond wire parasitic’s and verified by post layout simulation. At the last we conclude by proposing a novel architecture for constant voltage battery charging.

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42

Zhao, Ping. "Energy Harvesting Techniques for Autonomous WSNs/RFID with a Focus on RF Energy Harvesting". Phd thesis, 2012. https://tuprints.ulb.tu-darmstadt.de/3102/1/phd_diss_ZhaoPing.pdf.

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Supply circuits that harvest energy from surrounding ambient or dedicated sources have drawn much interest recently for providing a possibility of energy-autonomy to the wireless sensing devices. The objective of this thesis is to optimize the power transfer efficiency of the RF/microwave energy transducers in WSN/RFID applications. For this purpose, analysis on the power utilization of the wireless devices at different working states has been done, which implies a space of improving the power transfer efficiency by employing a novel design concept in the RF/microwave energy transducers. In order to observe a deep insight of the charge-pump based energy transducer, an analytical derivation has been implemented based on a compact I/V model for MOSFET working in strong inversion and subthreshold regions. The derivation provides a mathematical direction for the impact of the power consumption of the wireless device on the input impedance of the charge-pump rectifier, which acts as a core element in the energy transducer. With expressing the input impedance of the rectifier into a shunt connection of a resistor and a capacitor, as the load current consumption reduces the shunt resistance increases dramatically while the shunt capacitance holds a relatively constant value. This work proposes a methodology of employing an adaptively adjusted matching network between the rectifier and the antenna in order to optimize the power transfer efficiency according to the instant power consumption of the wireless devices on different working states. For read-only wireless devices with no embedded batteries, like RFID transponders, a tiny storage capacitor of pico-farad which can be charged-up to a certain voltage in microseconds is usually employed as a DC supplier. During the communication between reader and transponder, the reader radiates RF power continuously to supply the transponder. Extra power supply is required to adjust the matching network electrically for optimal power transfer, which raises a new challenge to the batteryless devices. A solution is proposed in this work that an auxiliary rectifier with a smaller constant load current consumption is employed to supply the feedback control circuitries. Besides, the abovementioned methodology is also applied in charging-up procedure of a wireless device which employs a supercapacitor as its charge storage. The charging-up procedure is extended to hours due to the huge volume of the capacitive storage, and the charging speed becomes a critical issue. During the charging-up, the output voltage of the recti- fier increases exponentially, while the charging current reduces exponentially. The input impedance derived for steady-state is not precisely applicable yet theoretically directive in this situation. A novel application of adaptively tunable matching network in transient process is implemented to accelerate the charging process of the wireless devices.

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43

Lin, Chih-Hsi y 林之曦. "Design of Wearable Low Power RF Energy Harvesting Rectenna". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/hc434w.

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碩士
國立宜蘭大學
電子工程學系碩士班
106
The thesis aims at designing wearable low-power RF energy harvesting rectenna for healthcare, monitoring or the sensor on the human body. The rectenna has a rectifier and a patch antenna which is linear-polarized. The harvester was operated in the 2.45 GHz band and the 5.8 GHz band to capture the electromagnetic radiation energy. The choice of fabric and the electrical properties of the material are very important due to design for wearable devices. The wearable textile material we selected for on-body applications is cordura fabric. Using Schottky diodes to design a RF/DC rectifier, and utilizing ADS simulator to simulate the designed circuit, impedance matching between the rectifier and the half wavelength patch antenna were performed to achieve maximum power transferring. The rectifier is a single-stage full-wave Greinacher rectifier where we added a radio frequency choke (RFC) to isolate the influence of the load on the input RF signal. Traditionally, different loads will result in different impedance mismatch so that it results in a small output voltage. However, the resonant frequency is relatively stable in our case after adding the RF chokes. The output DC voltage of the 2.45 GHz rectenna can achieve 2.2 volts, while the 5.8 GHz rectenna can achieve 1.9 volts when the RF power is swept from -40 dBm to 0 dBm. The top surface of the rectifier is directly attached to the human body but our body is a lossy media. The study finds that the foam with copper foil added on the top surface of the rectifier helps to isolate the body-proximity effect on the rectifier. A TOTOLINK's AC1200 WiFi router was utilized as a WiFi radiation source in the indoor environment. The measurement results shows the foam has the feature of good isolation. The size of the rectenna measures only 80 × 80 × 2.2 mm. In addition to discussing how to match with a single-element rectenna, the rectenna is extended to a 2×2 rectenna array for generating sufficient DC power. The power transmission distance of the 2×2 array rectenna is from 60 cm to 150 cm. The output voltage is preserved between 1 volt and 3 volts. When the isolation S21 between the antenna and the antenna is less than -25 dBm, the minimum size is only 160 × 130 × 2.2 mm. The size is small enough to suitably paste on the back of the human body. Assuming a load of 1 MΩ, the maximum efficiency of the single element 2.45 GHz rectenna is only 10%, but the maximum efficiency of the 2×2 array rectenna can increase to 35%, reaching the best efficiency rectenna design that we expected.

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44

You, Jing-Wei y 游景崴. "Characterization of Antenna Design for Indoor RF Energy Harvesting". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/3g754w.

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碩士
國立臺北科技大學
電子工程系
106
In this paper, the radiation features of radio-frequency (RF) energy-harvesting antennas are analyzed, and the design guidelines that enhance receiving power is proposed. It is acknowledged that an RF energy-harvesting antenna is desired to depict circular polarization (CP) and omnidirectional patterns, as ambient sources are omni-presented; however, the polarization features and half-power beamwidth (HPBW) of the antenna are inconclusive in earlier studies. To clarify the requirement of radiation characteristics, we analyze the receiving performance of six antennas with different HPBWs and polarizations. Our research methodology is a modified shooting-and-bouncing-ray technique, which traces multipath propagation in an indoor environment. These antennas are placed at different locations in a room, and the orientation angles are evenly and uniformly sampled. The receiving performance of each antenna is cast into cumulative density functions, which enable us to identify the antenna that provides the maximum amount of successful reception at a given energy-harvesting sensitivity. The simulated results are verified by performing measurement. Surprisingly, our results depict that CP and omnidirectional patterns cannot offer the most favorable receiving performance; in contrast, linear polarization and unidirectional patterns with a narrow HPBW are desired in most of the scenarios, even though the orientation angles have been uniformly sampled.

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45

Huang, Yi-Hao y 黃奕豪. "A Dual-Band Loop Rectenna for RF Energy Harvesting". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/94hm42.

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碩士
國立臺灣科技大學
電子工程系
106
This study is the dual-band rectenna that apply to the home wireless access point (WAP or AP) for wireless energy harvesting. At present, most of the mainstream wireless receivers are dual-band 2.4 GHz (2.400 to 2.500 GHz) and 5 GHz (5.725 to 5.875 GHz) settings, so the design of the rectenna frequency is also for this dual band. Since the antenna of the home wireless receiver is a linear polarization monopole antenna, the design of the dual-band rectenna in this study is based on a loop antenna. The dual-band effect can be achieved by the turning of the antenna architecture, the calculation of two different frequency wavelengths, and the sector shape stub. Because of the single feed, the two resonant input impedances are designed to be 50 Ω. Through the simulation software, a good return loss -16.5 dB and -28.5 dB can be achieved by appropriately adjusting the antenna size at 2.45 GHz and 5.8 GHz, respectively. Finally, the transmission efficiency is up to 58.2% and 31% at 2.45 GHz and 5.8 GHz, respectively. The proposed structure combine antenna with rectifier circuit, the receiving RF energy which in front of the antenna, through the rectifier circuit can convert to DC output. When the distance between the transmitted horn antenna and the receiving antenna is 10 cm, the resistance of the load can be measured the output voltage is about 1.2 V.

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46

Liu, Yu-Chun. "RF Energy Harvesting for Implantable ICs with On-chip Antenna". Master's thesis, 2014. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/6129.

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Nowadays, as aging population increasing yearly, the health care technologies for elder people who commonly have high blood pressure or Glaucoma issues have attracted much attention. In order to care of those people, implantable integrated circuits (ICs) in human body are the direct solution to have 24/7 days monitoring with real-time data for diagnosis by patients themselves or doctors. However, due to the small size requirement for the implanted ICs located in human organs, it's quite challenging to integrate with transmitting and receiving antenna in a single chip, especially operating in 5.8-GHz ISM band. This research proposes a new idea to solve the issue of integrating an on-chip antenna with implanted ICs. By adding an additional dielectric substrate upon the layer of silicon oxide in CMOS technology, utilizing the metal-6, it can form an extremely compact 3D-structure on-chip antenna which is able to be placed in human eye, heart or even in a few mm-diameter vessels. The proposed 3D on-chip antenna is only 1x1x2.8 mm3 with -10 dB gain and 10% efficiency, which has capability to communicate at least within 5 cm distance. The entire implanted battery-less wireless system has also been developed in this research. A designed 30% efficiency Native NMOS rectifier could generate 1 V and 1 mA to supply the designed low power transmitter including voltage-controlled oscillator (VCO) and power amplifier (PA). The entire system performance is well evaluated by link budget analysis and the simulation result demonstrates the possibility and feasibility of future on-demand easy-to-design implantable SoC.
M.S.E.E.
Masters
Electrical Engr & Computing
Engineering and Computer Science
Electrical Engineering

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47

Tain, Longwen-Wen y 譚隆文. "An RF Energy Harvesting Circuit design Using Resonator Coupling Technique". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/26809468915003195003.

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碩士
國立交通大學
電機學院電子與光電學程
103
The technology of semiconductor process is getting to forge ahead vigorously, which enables the miniature autonomy devices designed with low power consumption (for example, passive RFID tag or wireless sensor node) after utilizing their internal power management circuit, so as to upgrade their efficiency in power-saving and energy use. The potentials to use energy harvesting circuit for energy conversion by way of mechanical vibration, heat, solar energy, and radio energy, into power storage equipment giving power supply for low power consumption devices are becoming popular. Increasing the conversion efficiency of Energy Harvesting circuit is the most important factor in acceptance. Recently wireless communication gadgets (such as hand-held mobile phone and wireless LAN router) are booming in popularity, various radio signals scatter in air, so that these RF electromagnetic waves are kind of excellent energy resources as an input energy of the RF energy harvester. In general, to improve RF harvester’s power transfer efficiency, the traditional RF energy harvester will add an impedance matching circuit between antenna and voltage rectifier, which consists of inductor and capacitor with high quality factor (Q value), [1-3][5][11-13][17], as a result, its input operation bandwidth becomes narrow. In this thesis, we design a far-field RF energy harvester including an on-chip transformer between antenna and voltage rectifier as resonator coupling impedance matching circuit to gain wider operation bandwidth and larger voltage (or current) gain. The operation center frequency of this work is 2450 MHz and its operation 3dB bandwidth is 850 MHz, and its sensitivity is -14dBm under test condition while output DC voltage 1V and current 2uA. The power conversion efficiency is 10.2% while RF input power is -7dBm. The chip is implemented in TSMC 0.18 um 1P6M CMOS process, and its size is 832 x 735 um2.

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48

Balakumar y 巴拉. "CMOS RF Energy Harvesting System with Improved Voltage Conversion Efficiency". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/06382532747794295366.

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碩士
國立中興大學
電機工程學系所
100
Energy Harvesting is a challenging task nowadays since there are many Energy harvesting techniques like solar, piezoelectric, vibration, thermal and so on RF energy harvesting has been attractive these days due to its ability to convert from ambient air into electrical Energy. The availability of RF Power is quite less compared to other kind of sources. It deals with designing the following blocks such as power conversion (AC-DC) unit , matching network and power management (DC-DC boost Converter) in order to charge some low power portable devices. In RF power harvesting circuit the energy from the RF is drawn by antenna which is converted to dc voltage through integrated rectifier circuit from the available low power ambient air which is very low at the end. Hence in order to increase the voltage a very low DC-DC integrated boost converter with low startup voltage is proposed. The proposed system is designed in TSMC 0.18um 1P6M CMOS technology which the circuits can startup with the feasible low power of 128uW. It can give the output voltage with the better efficiency over traditional circuit while driving maximum of 5MΩ resistive loading. It operates at frequency of 900MHZ.

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49

Lin, Shu-Hsuan y 林書玄. "Wide Input Range Power-Management System for RF Energy Harvesting". Thesis, 2016. http://ndltd.ncl.edu.tw/handle/87491137910932146759.

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50

Dolgov, Arseny Borisovitch. "Power management system for online low power RF energy harvesting optimization". Thesis, 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1464493.

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