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Chan, Chee Wai. "Distributed beamforming in wireless sensor networks." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Dec%5FChan.pdf.
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Thesis (M.S. in Engineering Science (Electrical Engineering))--Naval Postgraduate School, Dec. 2004.<br>Thesis Advisor(s): Murali Tummala, Roberto Cristi. Includes bibliographical references (p. 79-81). Also available online.
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Wu, Terence. "Antenna integration for wireless and sensing applications." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41098.
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As integrated circuits become smaller in size, antenna design has become the size limiting factor for RF front ends. The size reduction of an antenna is limited due to tradeoffs between its size and its performance. Thus, combining antenna designs with other system components can reutilize parts of the system and significantly reduce its overall size. The biggest challenge is in minimizing the interference between the antenna and other components so that the radiation performance is not compromised. This is especially true for antenna arrays where the radiation pattern is important.
Antenna size reduction is also desired for wireless sensors where the devices need to be unnoticeable to the subjects being monitored. In addition to reducing the interference between components, the environmental effect on the antenna needs to be considered based on sensors' deployment.
This dissertation focuses on solving the two challenges: 1) designing compact multi-frequency arrays that maintain directive radiation across their operating bands and 2) developing integrated antennas for sensors that are protected against hazardous environmental conditions.
The first part of the dissertation addresses various multi-frequency directive antennas arrays that can be used for base stations, aerospace/satellite applications. A cognitive radio base station antenna that maintains a consistent radiation pattern across the operating frequencies is introduced. This is followed by multi-frequency phased array designs that emphasize light-weight and compactness for aerospace applications. The size and weight of the antenna element is reduced by using paper-based electronics and internal cavity structures.
The second part of the dissertation addresses antenna designs for sensor systems such as wireless sensor networks and RFID-based sensors. Solar cell integrated antennas for wireless sensor nodes are introduced to overcome the mechanical weakness posed by conventional monopole designs. This can significantly improve the sturdiness of the sensor from environmental hazards. The dissertation also introduces RFID-based strain sensors as a low-cost solution to massive sensor deployments. With an antenna acting as both the sensing device as well as the communication medium, the cost of an RFID sensor is dramatically reduced. Sensors' strain sensitivities are measured and theoretically derived. Their environmental sensitivities are also investigated to calibrate them for real world applications.
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Zhu, Danny. "Source localization within a uniform circular sensor array /." Online version of thesis, 2007. http://hdl.handle.net/1850/4628.
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Zhang, Boyang. "Real-time software-defined-radio implementation of time-slotted carrier synchronization for distributed beamforming." Worcester, Mass. : Worcester Polytechnic Institute, 2009. http://www.wpi.edu/Pubs/ETD/Available/etd-050509-200154/.
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Thesis (M.S.)--Worcester Polytechnic Institute.<br>Keywords: distributed beamforming; carrier synchronization; software-defined-radio; sensor networks; wireless networks; cooperative transmission; virtual antenna arrays. Includes bibliographical references (leaves 168-169).
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Cheng, Shi. "Integrated Antenna Solutions for Wireless Sensor and Millimeter-Wave Systems." Doctoral thesis, Uppsala universitet, Mikrovågs- och terahertzteknik, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-111197.
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This thesis presents various integrated antenna solutions for different types of systems and applications, e.g. wireless sensors, broadband handsets, advanced base stations, MEMS-based reconfigurable front-ends, automotive anti-collision radars, and large area electronics. For wireless sensor applications, a T-matched dipole is proposed and integrated in an electrically small body-worn sensor node. Measurement techniques are developed to characterize the port impedance and radiation properties. Possibilities and limitations of the planar inverted cone antenna (PICA) for small handsets are studied experimentally. Printed slot-type and folded PICAs are demonstrated for UWB handheld terminals. Both monolithic and hybrid integration are applied for electrically steerable array antennas. Compact phase shifters within a traveling wave array antenna architecture, on single layer substrate, is investigated for the first time. Radio frequency MEMS switches are utilized to improve the performance of reconfigurable antennas at higher frequencies. Using monolithic integration, a 20 GHz switched beam antenna based on MEMS switches is implemented and evaluated. Compared to similar work published previously, complete experimental results are here for the first time reported. Moreover, a hybrid approach is used for a 24 GHz switched beam traveling wave array antenna. A MEMS router is fabricated on silicon substrate for switching two array antennas on a LTCC chip. A concept of nano-wire based substrate integrated waveguides (SIW) is proposed for millimeter-wave applications. Antenna prototypes based on this concept are successfully demonstrated for automotive radar applications. W-band body-worn nonlinear harmonic radar reflectors are proposed as a means to improve automotive radar functionality. Passive, semi-passive and active nonlinear reflectors consisting of array antennas and nonlinear circuitry on flex foils are investigated. A new stretchable RF electronics concept for large area electronics is demonstrated. It incorporates liquid metal into microstructured elastic channels. The prototypes exhibit high stretchability, foldability, and twistability, with maintained electrical properties.<br>wisenet
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Lee, Eugene Y. "Electromagnetically Transparent Feed Networks for Antenna Arrays." The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1218569942.
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Laue, Heinrich Edgar Arnold. "Design of compressive antenna arrays." Thesis, University of Pretoria, 2020. http://hdl.handle.net/2263/73316.
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Reduced-control antenna arrays reduce the number of controls required for beamforming while maintaining a given array aperture. A reduced-control array for direction finding (DF), inspired by the concept of compressive sensing (CS), was recently proposed which uses random compression weights for combining antenna-element signals into fewer measurements. However, this compressive array had not been studied in terms of traditional characteristics such as directivity, sidelobe level (SLL) or beamwidth. In this work, random compression weights are shown to be suboptimal and a need for the optimisation of compressive arrays is expressed. Existing codebook optimisation algorithms prove to be the best starting point for the optimisation of compressive arrays, but are computationally complex. A computationally efficient codebook optimisation algorithm is proposed to address this problem, which inspires the compressive-array optimisation algorithm to follow. Compressive antenna arrays are formulated as a generalisation of reduced-control arrays and a framework is presented for their optimisation in terms of SLL. By allowing arbitrary compression weights, compressive arrays are shown to improve on existing reduced-control techniques. A feed network consisting of interconnected couplers and fixed phase shifters is proposed, enabling the implementation of compressive arrays in microwave hardware. The practical feasibility of compressive arrays is illustrated by successfully manufacturing a 3-GHz prototype compressive array with integrated antenna elements.<br>Thesis (PhD)--University of Pretoria, 2020.<br>Electrical, Electronic and Computer Engineering<br>PhD<br>Unrestricted
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Manninen, O. (Olli). "Modelling the antenna arrays using MATLAB-application Sensor Array Analyzer." Bachelor's thesis, University of Oulu, 2017. http://urn.fi/URN:NBN:fi:oulu-201705302196.
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In this thesis, the antenna arrays researched and modelled using Sensor Array Analyzer- application (SAA) from MATLAB. The objective is to explore the array modelling capabilities of the SAA application. This thesis shows that SAA is versatile software for modelling the radiation patterns using 2D or 3D plots, but there are couple of missing features. SAA allows user to import the used code to MATLAB for code modification. Data imported from MATLAB to SAA using variables, for example importing dipole, antenna locations for conformal array and complex coefficients for beamforming. Antenna array wideband usage at SAA discussed and example shown. At SAA, grating lobes seen at 2D and 3D plots and grating lobe- diagram is also used and explained. SAA has no built-in option for mutual coupling compensation. Other practical method for modelling and compensation of mutual coupling are discussed<br>Tässä kandidaatintyössä tutkittiin eri geometrian omaavia antenniryhmiä ja niiden mallinnusta MATLAB-ohjelmiston lisäosan SAA:n (Sensor Array Analyzer) avulla. Tehtävänä oli tutkia antenniryhmän eri osa-alueiden mallinnuksen mahdollisuuksia ja rajoituksia kyseisellä ohjelmistolla. Tutkimuksen tuloksena todetaan, että SAA on monipuolinen ohjelmisto antenniryhmien säteilykuvioiden graafiseen havainnollistamiseen 2D- tai 3D-muodossa, vaikkakin muutama perusominaisuus puuttui. Työssä tutkittiin, miten SAA-ohjelmistosta voidaan siirtää käytetty koodi MATLAB-ohjelmistoon sen mahdollista lisämuokkausta varten ja kuinka MATLAB-ohjelmistosta tuodaan tietoa SAA-ohjelmistoon erilaisina muuttujina. Muuttujia tarvitaan esimerkiksi, kun ohjelmistoon tuodaan antennin säteilykuvio, tai sovellettu antenniryhmä sekä niiden kompleksiset kertoimet keilanmuodostusta varten. Laajakaistaisten antenniryhmien säteilykuvion mallinnusta testattiin ja havainnollistettiin. Sivukeiloja, joilla on sama teho pääkeilan kanssa, tarkasteltiin ja niiden havainnollistamiseen luotua diagrammia testattiin. Antennien välisen keskinäiskytkennän mallintamisen mahdollisuuksia tarkasteltiin ja sen vaikutusta säteilykuvioon pohdittiin. Tämän työn tarkoituksena oli selvittää SAA-ohjelmiston pääpiirteiset ominaisuudet ja heikkoudet. Kyseistä tietoa käytetään antenniryhmien keilasynteesiä tutkiessa. Antenniryhmiä voi mallintaa huomattavasti nopeammin ja helpommin käyttämällä SAA-ohjelmistoa, kuin kirjoittamalla itse MATLAB-koodi tai simuloimalla antenniryhmän sähkömagneettinen 3D-malli. Ohjelmiston heikkoudetkin voidaan välttää muokkaamalla koodia haluamalla tavalla. Antenniryhmiä tullaan tulevaisuudessa hyödyntämään IoT-laitteissa ja langattomassa 5G teknologiassa
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Dyberg, Karin, and Linda Farman. "Spatial TDMA in Ad Hoc Networks with Antenna Arrays." Thesis, Linköping University, Department of Science and Technology, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-1104.
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<p>In modern military operations the requirements of transmitting large amounts of information have increased substantially during the last decade. This increases the demand for high-capacity radio networks. It is also very important that military decisions are made on recent and correct information and this implies that low and known delays are required. The existing military radio ommunications, within the Swedish army, do not meet the requirements for capacity and delay. </p><p>We have investigated how the capacity and average delay can be improved in an Ad Hoc network with STDMA by using antenna arrays. The study is based on different antenna combinations consistingof single isotropic antenna element, beam steering and adaptive beamforming. We have also studied how the number of antenna elements, the terrain, and an increased connectivity due to the antenna arrays_affects the performance measurements. </p><p>The study shows that the capacity is improved with up to 1200%, and the average delays are decreased when using antenna arrays instead of single isotropic antenna elements. Depending on the beamforming combination used the capacity gain and average delay reduction will differ. The way of using the antenna array also affects the capacity gain and average delay. The capacity gain is higher when the antenna array is used not only to suppress and decrease interferences, but also to increase the connectivity. </p><p>The study also shows that the capacity gain is higher when using more antenna elements for a network with a high number of links, than with fewer. The benefit from antenna arrays is higher in a flat terrain than in a rough.</p>
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Gelal, Ece. "Cross-layer design for wireless networks using antenna arrays." Diss., [Riverside, Calif.] : University of California, Riverside, 2009. http://proquest.umi.com/pqdweb?index=0&did=1899476681&SrchMode=2&sid=1&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1268335334&clientId=48051.
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Thesis (Ph. D.)--University of California, Riverside, 2009.<br>Includes abstract. Title from first page of PDF file (viewed March 11, 2010). Available via ProQuest Digital Dissertations. Includes bibliographical references (p. 149-156). Also issued in print.
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Ward, James. "High throughput packet radio networks with adaptive antenna arrays /." The Ohio State University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487683756124864.
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Marinho, Marco Antonio Marques. "Array interpolation methods with applications in wireless sensor networks and global positioning systems." reponame:Repositório Institucional da UnB, 2013. http://repositorio.unb.br/handle/10482/15614.
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Dissertação (mestrado)—Universidade de Brasília, 2013.<br>Submitted by Alaíde Gonçalves dos Santos (alaide@unb.br) on 2014-05-08T14:55:32Z
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2013_MarcoAntonioMarquesMarinho.pdf: 1381668 bytes, checksum: b6f72e816a7a328699ea1ba4dfea1336 (MD5)<br>Nas últimas três décadas o estudo de técnicas de processamento de sinais em arranjos de sensores tem recebido grande atenção. Uma grande quantidade de técnicas foi desenvolvida com diversas finalidades como a estimação da direção de chegada, a filtragem ou separação espacial dos sinais recebidos, a estimação do atraso de propagação, a estimação da frequência Doppler e a pré-codificação de sinais na transmissão para maximização da potência recebida por outro arranjo. Técnicas para estimação da direção de chegada são de particular interesse para sistemas de posicionamento baseado em ondas de rádio, como os sistemas de posicionamento global e para o mapeamento de sensores em redes de sensores. Uma particularidade dessas aplicações é a necessidade de uma estimação em tempo real ou computacionalmente eficiente. Técnicas de estimação da direção de chegada que atendem esses requisitos requerem uma estrutura muito específica do arranjo de antenas que, em geral, não pode ser obtida em implementações reais. Nesse trabalho é apresentado um conjunto de técnicas que permitem a interpolação de sinais recebidos em arranjos de geometria arbitrária para arranjos de geometria específica, de forma eficiente e robusta, para possibilitar a aplicação de técnicas eficientes para estimação da direção de chegada em arranjos de geometria arbitrária. Como aplicações das técnicas propostas são apresentados o mapeamento preciso em redes de sensores e posicionamento preciso em receptores de sistemas de posicionamento global. _______________________________________________________________________________________ ABSTRACT<br>In the last three decades the study of antenna array signal processing techniques has received significant attention. A large number of techniques have been developed with different purposes such as the estimation of the direction of arrival (DOA), filtering or spatial separation of received signals, estimation of time delay of arrival (TDOA), Doppler frequency estimation and precoding of transmitted signals to maximize the power received by a different array. DOA estimation techniques are of particular interest for positioning systems based on radio waves such as the global positioning system (GPS) and for sensor mapping in wireless sensor networks (WSNs). These applications have the particular requirement of demanding the estimations to be made in real time or with reduced computational complexity. DOA estimation techniques that fulfill these requirements demand very specific antenna array structures that cannot, in general, be obtained in real implementations. In this work a set of techniques is presented that allows the interpolation of signals received in arrays of arbitrary geometry into arrays of specific geometry efficiently and robustly to allow the application of efficient DOA estimation techniques in arrays of arbitrary geometry. As an application of the proposed techniques precise mapping for WSNs and precise positioning for GPS receivers is presented.
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Jobs, Magnus. "Design and Performance of Diversity based Wireless Interfaces for Sensor Network Nodes." Licentiate thesis, Uppsala universitet, Fasta tillståndets elektronik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-198734.
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The main focus of the work presented in this licentiate thesis concerns antenna design, adaptive antenna control and investigation on how the performance of small wireless nodes can be increased by inclusion of multiple antennas. In order to provide an end-user suitable solution for wireless nodes the devices require both small form factor and good performance in order to be competitive on the marked and thus the main part of this thesis focuses on techniques developed to achieve these goals. Two prototype systems have been developed where one has been used by National Defence Research Agency (FOI) to successfully monitor a test-subject moving in an outdoor terrain. The other prototype system shows the overall performance gain achievable in a wireless sensor node when multiple antennas and antenna beam steering is used. As an example of how to include multiple antennas in a wireless node the concept of using dual conformal patch antennas for wireless nodes is presented. The proposed antenna showed an excess of 10 dB gain when using a single driven antenna element as would be the case in a system utilizing antenna selection combining. When used as a 2-element phased array, up to 19 dB gain was obtained in a multiscattering environment. Using the second order resonance the proposed antenna structure achieves low mutual coupling and a reflection coefficient lower than -15 dB. The presented antenna design shows how a dual antenna wireless node can be designed using discrete phase control with passive matching which provides a good adaptive antenna solution usable for wireless sensor networks. The inclusion of discrete phase sweep diversity in a wireless node has been evaluated and shown to provide a significant diversity gain. The diversity gain of a discrete phase sweep diversity based system was measured in both a reverberation chamber and a real life office environment. The former environment showed between 5.5 to 10.3 dB diversity gain depending on the detector architecture and the latter showed a diversity gain ranging from 1 to 5.4 dB. Also the performance of nodes designed to be placed in a high temperature and multiscattering environment (the fan stage of a jet engine) has been evaluated. The work was carried out in order to verify that a wireless sensor network is able to operate in such a multiscattering environment. It was shown that the wireless nodes are able to operate in an emulated turbine environment based on real-life measured turbine fading data. The tested sensor network was able to transmit 32 byte packages using cyclic redundancy check at 2 Mbps at an engine speed of 13.000 rpm.<br>WISENET<br>WISEJET
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Ren, Tianmin. "Cross-layer resource allocation algorithms in wireless networks with antenna arrays." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/2595.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2005.<br>Thesis research directed by: Electrical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Lopez, Michael J. (Michael John) 1972. "Multiplexing, scheduling, and multicasting strategies for antenna arrays in wireless networks." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/16896.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.<br>Includes bibliographical references (p. 167-174).<br>This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.<br>A transmitter antenna array has the ability to direct data simultaneously to multiple receivers within a wireless network, creating potential for a more integrated view of algorithmic system components. In this thesis, such a perspective informs the design of two system tasks: the scheduling of packets from a number of data streams into groups; and the subsequent spatial multiplexing and encoding of these groups using array processing. We demonstrate how good system designs can help these two tasks reinforce one another, or alternatively enable tradeoffs in complexity between the two. Moreover, scheduling and array processing each benefit from a further awareness of both the fading channel state and certain properties of the data, providing information about key flexibilities, constraints and goals. Our development focuses on techniques that lead to high performance even with very low-complexity receivers. We first consider spatial precoding under simple scheduling and propose several extensions for implementation, such as a unified time-domain precoder that compensates for both cross-channel and intersymbol interfer- ence. We then show how more sophisticated, channel-aware scheduling can reduce the complexity requirements of the array processing. The scheduling algorithms presented are based on the receivers' fading channel realizations and the delay tolerances of the data streams. Finally, we address the multicasting of common data streams in terms of opportunities for reduced redundancy as well as the conflicting objectives inherent in sending to multiple receivers. Our channel-aware extensions of space-time codes for multicasting gain several dB over traditional versions that do not incorporate channel knowledge.<br>by Michael J. Lopez.<br>Ph.D.
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Da, Silveira Marthinus Willem. "Analysis of spatially distributed adaptive antenna array systems in cellular networks." Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-06032005-090336/.
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Gemio, Valero Joan. "Multiband and Silicon Integrated Antennas for Wireless Sensor Networks." Doctoral thesis, Universitat Autònoma de Barcelona, 2011. http://hdl.handle.net/10803/79096.
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Les tecnologies sense fils han provocat una important revolució en el món de les xarxes i serveis de telecomunicació. Han apareguts nous sistemes com els telèfons mòbils d'última generació o les xarxes LAN sense fils que han estat acceptats amb entusiasme per la població. En particular, l'ús de xarxes de sensors (per controlar la temperatura, per a detectar places lliures d'aparcament, etc.) està creixent ràpidament . Aquesta tesi es centra en el disseny d'antenes per a xarxes de sensors distribuïts. En concret s'analitza un sistema on els sensors remots estan connectats a una unitat central utilitzant un radio enllaç operant en la banda ISM de 5,8 GHz, i la unitat central envia la informació recollida a Internet a través d'una connexió WLAN. A la unitat central es necessiten antenes multibanda per cobrir diverses bandes de freqüències amb un únic element radiant. En aquesta tesi es presenten dues solucions per obtenir aquest comportament multibanda: Monopols amb pla de massa fractal i monopols carregats amb ressonadors. S'han fabricat i mesurat diferents prototips que cobreixen les necessitats del sistema. Els sensors han de ser dispositius de reduïdes dimensions i baix cost. Una bona opció per aconseguir aquests requisits és l'ús d'antenes integrades en silici fabricades amb una tecnologia CMOS estàndard. En primer lloc s'analitzen els principals problemes de la integració de l'antena en silici, i a continuació es presenta una possible solució per millorar l'eficiència juntament amb un estudi de la degradació introduïda per altres components quan aquests es fabriquen en el mateix xip que l’antena. Les mesures dels prototips fabricats demostren que la integració de l'antena en la banda de 5,8 GHz és factible, obtenint un abast d'alguns metres.
Cada vegada és una realitat més propera el fet de tenir sensors implantats en el cos. Per aquest motiu, l’última part d'aquesta tesi es dedica a estudiar els efectes del cos sobre antenes situades en el seu interior i avaluar les pèrdues de propagació addicionals introduïdes pels teixits humans.<br>Las tecnologías inalámbricas han provocado una importante revolución en el mundo de las redes y servicios de telecomunicación. Han aparecidos nuevos sistemas, como los teléfonos móviles de última generación o las redes LAN inalámbricas, que han sido aceptados con entusiasmo por la población. En particular, el uso de redes de sensores (para controlar la temperatura, para detectar plazas libres de aparcamiento, etc.) está creciendo rápidamente. Esta tesis se centra en el diseño de antenas para redes de sensores inalámbricos distribuidos. EN concreto se analiza un sistema donde los sensores están conectados a una unidad central utilizando un enlace inalámbrico en la banda ISM de 5.8 GHz, y la unidad central envía la información recogida a Internet a través de una conexión WLAN. En la unidad central se necesitan antenas multibanda para dar servicio a varias bandas de frecuencias con un único elemento radiante. En esta tesis se presentan dos soluciones para obtener este comportamiento multibanda: Monopolos con plano de masa fractal y monopolos cargados con resonadores. Se han fabricado y medido diferentes prototipos que cubren las necesidades del sistema. En los sensores se desean dispositivos de reducidas dimensiones y bajo coste. Una buena opción para lograr estos requisitos es el uso de antenas integradas en silicio fabricadas con una tecnología CMOS estándar. En primer lugar se analizan los principales problemas de la integración de la antena en silicio, y a continuación se presenta una posible solución para mejorar la eficiencia de radiación junto con un estudio de la degradación introducida por otros componentes cuando éstos se fabrican en el mismo chip que la antena. Las medidas de los prototipos fabricados demuestran que la integración de la antena en la banda de 5,8 GHz usando una tecnología CMOS es factible, obteniendo unos alcances de algunos metros incluso cuando la antena se fabrica junto con otros elementos integrados en el mismo chip. Cada vez es una realidad más cercana el hecho de poder tener sensores implantados en el cuerpo. Por este motivo, la última parte de esta tesis se dedica a estudiar los efectos del cuerpo sobre antenas situadas en su interior y evaluar las pérdidas de propagación adicionales introducida por los tejidos humanos.<br>Wireless technologies have triggered an important revolution in the world of telecommunication networks and services. New systems, such as the latest generation mobile phones or wireless LANs, have appeared being enthusiastically accepted by people. In particular, applications related to remote sensor networks are growing rapidly (for temperature monitoring, the detection of free parking spaces, etc.). This thesis is focused on antenna design for distributed wireless sensor networks. The remote sensors we are considering are connected to a central unit using a wireless link in the 5.8 GHz ISM band and the central unit transmits the collected information to the Internet via a WLAN connection. In the central unit multiband antennas are necessary to cover several frequency bands with a single radiating element. Two solutions to obtain this multiband performance are proposed: fractal-based ground planes and resonator loaded monopoles. Several novel antennas that easily meet the system requirements are manufactured and measured. For remote sensors small dimensions and low costs are desired. The use of silicon integrated antennas fabricated with standard CMOS technology is a good choice to achieve these requirements. First, the main problems of antenna integration are discussed and, then a possible solution to improve the antenna efficiency is presented together with a study of the effects of other elements integrated in the same chip with the antenna. The measurements of the manufactured prototypes demonstrate that antenna integration at 5.8 GHz is feasible, and that system ranges of some meters can be obtained even when the antenna is fabricated together with other elements integrated in the same chip.
The possibility of having some of the sensors implanted inside the body will be a reality in the near future, for this reason the particular case of implanted antennas is also analyzed. The last part of this thesis is devoted to study the body effects on antenna performance and evaluate the additional propagation losses introduced by the body tissues.
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Gheethan, Ahmad. "Novel Pattern Reconfigurable Antenna Arrays Using Engineered Metamaterials and Microfluidic Principles." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5223.
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This dissertation proposes novel solutions for important drawbacks of antenna arrays. One of the main contributions of the presented work is size reduction and nulling performance improvement of traditionally large anti-jam global positioning system (GPS) arrays using miniature antennas and electrically small resonators emulating an engineered metamaterial. Specifically, a miniaturized coupled double loop (CDL) dual band antenna is first introduced as a small antenna element of the compact GPS array. The loops that are capacitively coupled using lumped element capacitor, and employ metallic pins around their perimeter to improve the radiation efficiency by achieving a volumetric current distribution. This design is employed for the implementation of a compact 2x2 GPS array by reducing the inter-element spacing between the adjacent elements. However, having the antenna elements in close proximity of each other yields to a high mutual coupling and potentially degrades the nulling performance. The mutual coupling is performed by observing the magnetic field distribution within the array. It is noticed that the mutual coupling can be reduced by using metamaterial resonators. The right hand circular polarization (RHCP) radiation nature of the array complicates the mutual coupling suppression as compared to linear arrays. It is determined that split ring resonator (SRRs) are effective to mitigate the mutual coupling problem if placed strategically around the antenna elements. The study is verified experimentally where the mutual coupling is reduced by more than 10 dB. Lowering the mutual coupling improved the array's nulling capability by increasing the nulls depth by 8 dB as well as enhancing the accuracy of the nulls' locations.
The second major contribution of the presented work is to introduce a novel microfluidic based beam-scanning technique for the implementation of low cost mm-wave antenna arrays. Traditionally, beam scanning capability is obtained using mechanical steering of the entire antenna structure or electronic components such as switches or phase shifters. The former is bulky, whereas the latter technique requires integrating substantial and expensive hardware in the array's feed network. For instance, a beam-scanning 1x8 focal plane array (FPA) would employ 7 single pole double through (SPDT) switches in its feed network. If an 8x8 FPA is desired, then 8x7+8 switches are required that results in an efficient design in terms of power loss and cost. In this dissertation, the microfluidic principles are introduced for designing and implementing affordable beam scanning antenna array with high gain radiation. Specifically, a microfluidic-based focal plane array 1x8 (MFPA) is designed and implemented at 30 GHz. The proposed MFPA consists of microfluidic channels connecting reservoirs. Both of the channels and reservoirs are filled with a low loss dielectric solution, and the antenna is formed by using a small volume of liquid metal. The beam scanning capability is obtained by placing the array at the focal point of a microwave lens and moving the antenna among the reservoirs using a micropump. Therefore, the feed network is extremely simplified by avoiding using SPDT switches. In addition, a strategic design methodology for a completely passive resonant based corporate feed network is discussed. The array is characterized numerically and verified experimentally. The simulated and measured performances are in a very good agreement with ±300 FoV and > 21 dB realized gain. However, the array's radiation pattern exhibits high side lobe level (SLL) due to the resonant nature of the introduced corporate feed network. Consequently, new resonant and non-resonant straight based feed networks are introduced to alleviate the high SLL issue. Moreover, they are modeled with appropriate equivalent circuits in order to analyze the array's performance analytically in terms of -10 dB |S11| bandwidth and power loss. The analytical solution is based on the transmission line theory and two ports network analysis. It is verified with the full wave simulations and a very good agreement is observed. Using the straight feed network reduces the SLL to more than 20 dB relative the pattern's peak. This enhancement in the performance is verified experimentally as well by designing, fabricating and testing a 30 GHz MFPA fed using a resonant based straight network. A ±250 FoV is obtained with a SLL < -20 dB and 4% -10 dB |S11| bandwidth.
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Molony, Anna. "The application of fibre Bragg grating networks as strain sensors and as phased array antenna true time delay elements." Thesis, Aston University, 1996. http://publications.aston.ac.uk/15355/.
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The fabrication of in-fibre Bragg gratings, and the application of arrays of such gratings as strain sensors and as true time delay elements for the control of phased array antennas is reported. Chirped period Bragg gratings were produced using the fibre deformation fabrication technique, with chirps of between 2.9nm and 17.3nm achieved. Arrays of 5mm and 2mm long uniform period Bragg gratings were fabricated using the inscription method, for use as true time delay elements,dissimilar wavefronts and their spectral characteristics recorded. The uniform period grating arrays were used to create minimum time delays of 9.09ps, 19.02ps and 31ps; making them suitable for controlling phased array antennas operating at RF frequencies of up to 3GHz, with 10° phase resolution. Four 4mm long chirped gratings were produced using the dissimilar wavefronts fabrication method, having chirps of 7nm, 12nm, 20nm and 30nm, and were used to create time delays of between 0.3ps and 59ps. Hence they are suitable for controlling phased array antennas at RF frequencies of up to 48GHz. The application of in fibre Bragg gratings as strain sensors within smart structure materials was investigated, with their sensitivity to applied strain and compression measured for both embedded and surface mounted uniform period and fibre Fabry-Perot filter gratings. A fibre Bragg grating sensor demultiplexing scheme based on a liquid crystal filled Fabry-Perot etalon tuneable transmission filter was proposed, successfully constructed and fully characterised. Three characteristics of the LCFP etalon were found to pose operational limitations to its application in a Bragg grating sensor system; most significantly, the resonance peak wavelength was highly (-2,77nm/°C) temperature dependent. Several methods for minimising this temperature sensitivity were investigated, but enjoyed only limited success. It was therefore concluded that this type (E7 filled) of LCFP etalon is unsuitable for use as a Bragg grating sensor demultiplexing element.
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Curry, Clifford Richard. "Multiport broadband matching and its application in the design of feed networks for array antennas /." Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/6105.
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Jobs, Magnus. "Wireless Interface Technologies for Sensor Networks." Doctoral thesis, Uppsala universitet, Fasta tillståndets elektronik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-239400.
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The main focus of the work presented in this thesis concerns the development and improvement of Wireless Sensor Networks (WSNs) as well as Wireless Body Area Networks (WBANs). WSN consist of interlinked, wireless devices (nodes) capable of relaying data wirelessly between the nodes. The applications of WSNs are very broad and cover both wireless fitness monitoring systems such as pulse watches or wireless temperature monitoring of buildings, among others. The topics investigated in the work presented within this thesis covers antenna design, wireless propagation environment evaluation and modeling, adaptive antenna control and wireless nodes system design and evaluation. In order to provide an end-user suitable solution for wireless nodes the devices require both small form factor and good performance in order to be competitive on the marked and thus the main part of this thesis focuses on techniques developed and data collected to help achieve these goals. Several different prototype systems have been developed which have been used to measure data by the Swedish Defence Research Agency (FOI), GKN Aerospace Sweden AB, the Swedish Transport Administration. The system developed with GKN Aerospace was used to do real-time test measurements inside a running RM12 jet engine and required a substantial amount of measurements, environmental modeling and system validation in order to properly design a wireless system suitable for the harsh and fast fading environment inside a jet engine. For FOI improvements were made on a wearable wireless body area network initially developed during the authors master thesis work. Refinements included work on new generation wireless nodes, antenna packaging and node-supported diversity techniques. Work and papers regarding the design of different types of antennas suitable for wireless nodes are presented. The primary constraints on the presented antennas are the limited electrical size. The types of antennas developed include electrically small helix antennas manufactured both on stretchable substrates consisting of a PDMS substrate with Galinstan as the liquid metal conductors, screen printed silver ink for helix antennas and conformal dual patch antennas for wireless sensor nodes. Other standard type antennas are included on the wireless sensors as well.
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Fernandez, Vicente I. "Performance analysis for lateral-line-inspired sensor arrays." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/67581.
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Thesis (Ph. D.)--Joint Program in Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Mechanical Engineering; and the Woods Hole Oceanographic Institution), 2011.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 223-232).<br>The lateral line is a critical component of the fish sensory system, found to affect numerous aspects of behavior including maneuvering in complex fluid environments, schooling, prey tracking, and environment mapping. This sensory organ has no analog in modem ocean vehicles, despite its utility and ubiquity in nature, and could fill the gap left by sonar and vision systems in turbid cluttered environments. Yet, while the biological sensory system suggests the broad possibilities associated with such a sensor array, nearly nothing is known of the input processing and what information is available via the real lateral line. This thesis demonstrates and characterizes the ability of lateral-line-inspired linear pressure sensor arrays to perform two sensory tasks of relevance to biological and man-made underwater navigation systems, namely shape identification and vortex tracking. The ability of pressure sensor arrays to emulate the "touch at a distance" feature of the lateral line, corresponding to the latter's capability of identifying the shape of objects remotely, is examined with respect to moving cylinders of different cross sections. Using the pressure distribution on a small linear array, the position and size of a cylinder is tracked at various distances. The classification of cylinder shape is considered separately, using a large database of trials to identify two classification approaches: One based on differences in the mean flow, and one trained on a subset which utilizes information from the wake. The results indicate that it is in general possible to extract specific shape information from measurements on a linear pressure sensor array, and characterize the classes of shapes which are not distinguishable via this method. Identifying the vortices in a flow makes it possible to predict and optimize the performance of flapping foils, and to identify imminent stall in a control surface. Vortices in wakes also provide information about the object that generated the wake at distances much larger than the near-field pressure perturbations. Experimental studies in tracking a vortex pair and an individual vortex interacting with a flat plate demonstrate the ability to track vortices with a linear pressure sensor array from both small streamlined bodies and large flat bodies. Based on a theoretical analysis, the relationship between the necessary array parameters and the range of vortices of interest is established.<br>by Vicente I. Fernandez.<br>Ph.D.
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Marinho, Marco Antonio Marques. "Array processing techniques for direction of arrival estimation, communications, and localization in vehicular and wireless sensor networks." reponame:Repositório Institucional da UnB, 2018. http://repositorio.unb.br/handle/10482/32685.
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Tese (doutorado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Elétrica, 2018.<br>Submitted by Fabiana Santos (fabianacamargo@bce.unb.br) on 2018-09-13T20:37:22Z
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Previous issue date: 2018-09-13<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES).<br>Técnicas de processamentos de sinais para comunicações sem fio tem sido um tópico de interesse para pesquisas há mais de três décadas. De acordo com o padrão Release 9 desenvolvido pelo consorcio 3rd Generation Partnership Project (3GPP) sistemas utilizando múltiplas antenas foram adotados na quarta geração (4G) dos sistemas de comunicação sem fio, também conhecida em inglês como Long Term Evolution (LTE). Para a quinta geração (5G) dos sistemas de comunicação sem fio centenas de antenas devem ser incorporadas aos equipamentos, na arquitetura conhecida em inglês como massive multi-user Multiple Input Multiple Output (MIMO). A presença de múltiplas antenas provê benefícios como o ganho do arranjo, ganho de diversidade, ganho espacial e redução de interferência. Além disso, arranjos de antenas possibilitam a filtragem espacial e a estimação de parâmetros, ambos podem ser usados para se resolver problemas que antes não eram vistos pelo prisma de processamento de sinais. O objetivo dessa tese é superar a lacuna entre a teoria de processamento de sinais e as aplicações da mesma em problemas reais. Tradicionalmente, técnicas de processamento de sinais assumem a existência de um arranjo de antenas ideal. Portanto, para que tais técnicas sejam exploradas em aplicações reais, um conjunto robusto de métodos para interpolação do arranjo é fundamental. Estes métodos são desenvolvidos nesta tese. Além disso problemas no campo de redes de sensores e redes veiculares são tratados nesta tese utilizando-se uma perspectiva de processamento de sinais. Nessa tesa métodos inovadores de interpolação de arranjos são apresentados e sua performance é testada utilizando-se cenários reais. Conceitos de processamento de sinais são implementados no contexto de redes de sensores. Esses conceitos possibilitam um nível de sincronização suficiente para a aplicação de sistemas de múltiplas antenas distribuídos, o que resulta em uma rede com maior vida útil e melhor performance. Métodos de processamento de sinais em arranjos são propostos para resolver o problema de localização baseada em sinais de rádio em redes veiculares, com aplicações em segurança de estradas e proteção de pedestres. Esta tese foi escrita em língua inglesa, um sumário em língua portuguesa é apresentado ao final da mesma.<br>Array signal processing in wireless communication has been a topic of interest in research for over three decades. In the fourth generation (4G) of the wireless communication systems, also known as Long Term Evolution (LTE), multi antenna systems have been adopted according to the Release 9 of the 3rd Generation Partnership Project (3GPP). For the fifth generation (5G) of the wireless communication systems, hundreds of antennas should be incorporated to the devices in a massive multi-user Multiple Input Multiple Output (MIMO) architecture. The presence of multiple antennas provides array gain, diversity gain, spatial gain, and interference reduction. Furthermore, arrays enable spatial filtering and parameter estimation, which can be used to help solve problems that could not previously be addressed from a signal processing perspective. The aim of this thesis is to bridge some gaps between signal processing theory and real world applications. Array processing techniques traditionally assume an ideal array. Therefore, in order to exploit such techniques, a robust set of methods for array interpolation are fundamental and are developed in this work. Problems in the field of wireless sensor networks and vehicular networks are also addressed from an array signal processing perspective. In this dissertation, novel methods for array interpolation are presented and their performance in real world scenarios is evaluated. Signal processing concepts are implemented in the context of a wireless sensor network. These concepts provide a level of synchronization sufficient for distributed multi antenna communication to be applied, resulting in improved lifetime and improved overall network behaviour. Array signal processing methods are proposed to solve the problem of radio based localization in vehicular network scenarios with applications in road safety and pedestrian protection.
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Handfield, Joseph J. "High resolution source localization in near-field sensor arrays by MVDR technique /." Online version of thesis, 2007. http://hdl.handle.net/1850/5861.
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Yang, Bo. "Ultra small antenna and low power receiver for Smart Dust Wireless Sensor Networks." College Park, Md.: University of Maryland, 2009. http://hdl.handle.net/1903/9867.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2009.<br>Thesis research directed by: Dept. of Electrical and Computer Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Silase, Geletu Biruk. "Modeling the Behavior of an Electronically Switchable Directional Antenna for Wireless Sensor Networks." Thesis, Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-3026.
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Reducing power consumption is among the top concerns in Wireless Sensor Networks, as the lifetime of a Wireless Sensor Network depends on its power consumption. Directional antennas help achieve this goal contrary to the commonly used omnidirectional antennas that radiate electromagnetic power equally in all directions, by concentrating the radiated electromagnetic power only in particular directions. This enables increased communication range at no additional energy cost and reduces contention on the wireless medium. The SPIDA (SICS Parasitic Interference Directional Antenna) prototype is one of the few real-world prototypes of electronically switchable directional antennas for Wireless Sensor Networks. However, building several prototypes of SPIDA and conducting real-world experiments using them may be expensive and impractical. Modeling SPIDA based on real-world experiments avoids the expenses incurred by enabling simulation of large networks equipped with SPIDA. Such a model would then allow researchers to develop new algorithms and protocols that take advantage of the provided directional communication on existing Wireless Sensor Network simulators. In this thesis, a model of SPIDA for Wireless Sensor Networks is built based on thoroughly designed real-world experiments. The thesis builds a probabilistic model that accounts for variations in measurements, imperfections in the prototype construction, and fluctuations in experimental settings that affect the values of the measured metrics. The model can be integrated into existing Wireless Sensor Network simulators to foster the research of new algorithms and protocols that take advantage of directional communication. The model returns the values of signal strength and packet reception rate from a node equipped with SPIDA at a certain point in space given the two-dimensional distance coordinates of the point and the configuration of SPIDA as inputs.<br>Phone:+46765816263 Additional email: burkaja@yahoo.com
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Hinnemo, Malkolm. "Design of an Antenna for a Wireless Sensor Network for Trains." Thesis, Uppsala universitet, Fasta tillståndets elektronik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-164692.
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An antenna for a wireless sensor network for trains is designed and built. The network will monitor temperature and vibrations of the wheel bearings on the train wagons. Doing this will allow for an earlier detection of damaged wheels, which will ease planning of maintenance and reduce wear on the rails considerably. The requirement of the system is that it is to be installed without any cables attached to the sensor nodes. This calls for wireless communication, and that for that antennas are needed.A train is a difficult environment to transmit electromagnetic (EM) waves in. It is full of metal and EM-waves cannot pass through a conducting material. Having much metal in its vicinity also affects the function of the antenna. This needs to be taken into consideration when making the design.The constructed antenna is a small dual-layer patch antenna. Dual layer means that it is constructed out of two sheets known as substrates of isolating material with different characteristics. The lower one of these substrates is made in such a way that integration with a circuit board is possible. Such integration would reduce the production cost considerably. The antenna is designed for direct placement on a conducting surface. This surface could be part of the train. It uses the surrounding metal as a ground plane in order to reduce its size. The result is a small patch antenna with good radiation qualities in metallic surroundings. The longest side is 18.35 mm, equaling 14.9 % of the wavelength that the antenna is designed for.<br>WISENET
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Thanayankizil, Lakshmi V. "Opportunistic large array concentric routing algorithm (OLACRA) for upstream routing in wireless sensor networks." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26672.
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Thesis (M. S.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2009.<br>Committee Chair: Ingram, Mary Ann; Committee Member: Blough, Douglas; Committee Member: Sivakumar, Raghupathy. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Fahmy, Nader S. Todd Terence D. "Ad hoc networks with power-controlled multi-antenna systems: MAC protocols and multihop relaying applications." *McMaster only, 2005.
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Kövamees, Johan. "Electrically Steerable Phased-Arrays for 5G Sub-6 GHzMassive MIMO Active Antenna Units : Re-configurable Feed Networks." Thesis, Uppsala universitet, Institutionen för elektroteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-420712.
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During this project we have designed a new type of antenna that uses an array of antenna elements in order to emit electromagnetic radiation as signals and to be able to control the beam. After an extended time the design yielded a simulation which had the correct characteristics. After printing and constructing a prototype of the antenna it was tested in an anechoic chamber at Uppsala University. The array was divided into two different sub-arrays: the upper and the lower sub-arrays. Each of these consisted in itself of two sides: the long and the short sides. Each side had seven radiating elements, during the tests only one of the two sub-arrays (upper or lower) was running. Both sub-arrays are excited via a rat-race or 90 degree coupler. While the antenna was running it had 14 radiating elements and two phase shifters, two per sub-array and two per side. The idea was for a signal to travel passing the radiating elements and the phase shifter which would steer the induced electromagnetic signal in one direction, a traveling-wave array. This direction could be changed since the phase shifters were configurable in three different states per phase shifter, hence the induced electromagnetic beam was steerable. The beam was also steerable through the feed which was re-configurable, since there were two feeds per sub-array a phase shift could be introduced between the long and the short side. The beam steering range was between -2 degrees and 11 degrees oriented as 0 degrees would be a perpendicular line from the array to the receiving end. The design itself worked which could be stated from the results in the upper part of the array, the test results from the lower part however did not match the simulated results. This is likely due to an error in the construction of the antenna rather than the theory since the upper and lower part of the array was mirrored versions of each other. The phase shifters worked as intended in the bigger picture but were slightly different in the simulations compared to the physical ones, likely due to the same type of error source as regarding the full antenna.
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DeJean, Gerald Reuben. "Design of compact antennas in multilayer technology for wireless communications : WLAN applications." Available online, Georgia Institute of Technology, 2005, 2004. http://etd.gatech.edu/theses/available/etd-12092004-162859/unrestricted/dejean%5Fgerald%5Fr%5F200505%5Fmast.pdf.
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Thesis (M. S.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2005.<br>Joy Laskar, Committee Member ; Manos Tentzeris, Committee Member ; John Papapolymerou, Committee Chair. Includes bibliographical references.
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Bahceci, Israfil. "Multiple-Input Multiple-Output Wireless Systems: Coding, Distributed Detection and Antenna Selection." Diss., Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-08262005-022321/.
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Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2006.<br>Altunbasak, Yucel, Committee Chair ; Mersereau, Russell M., Committee Member ; Fekri, Faramarz, Committee Member ; Smith, Glenn, Committee Member ; Huo, Xiaoming, Committee Member. Includes bibliographical references.
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Kailas, Aravind. "Toward perpetual wireless networks: opportunistic large arrays with transmission thresholds and energy harvesting." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34720.
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Solving the key issue of sustainability of battery-powered sensors continues to attract significant research attention. The prevailing theme of this research is to address this concern using energy-efficient protocols based on a form of simple cooperative transmission (CT) called the opportunistic large arrays (OLAs), and intelligent exploitation of energy harvesting and hybrid energy storage systems (HESSs). The two key contributions of this research, namely, OLA with transmission threshold (OLA-T) and alternating OLA-T (A-OLA-T), offer an signal-to-noise ratio (SNR) advantage (i.e., benefits of diversity and array (power) gains) in a multi-path fading environment, thereby reducing transmit powers or extending range. Because these protocols do not address nodes individually, the network overhead remains constant for high density networks or nodes with mobility. During broadcasting across energy-constrained networks, while OLA-T saves energy by limiting node participation within a single broadcast, A-OLA-T optimizes over multiple broadcasts and drains the the nodes in an equitable fashion. Another important contribution of this research is the design and analysis of a novel routing metric called communications using HESS (CHESS), which extends the rechargeable battery (RB)-life by relaying exclusively with supercapacitor (SC) energy, and is asymptotically optimal with respect to the number of nodes in the network.
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Thanayankizil, Lakshmi. "Opportunistic large array (OLA)-based routing for sensor and adhoc wireless networks." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50374.
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An Opportunistic Large Array (OLA) is a form of cooperative diversity in which a large group of simple, inexpensive relays operate without any mutual coordination, but naturally fire together in response to the energy received from a single source or another OLA. The main contributions of this thesis are the introduction of two OLA-based routing protocols: OLA Concentric Routing Algorithm (OLACRA), which is an upstream routing algorithm suitable for static wireless sensor networks (WSNs), and OLA Routing On-Demand (OLAROAD), which is a robust reactive routing scheme suitable for mobile ad hoc networks (MANETs). In fixed multi-hop wireless sensor networks with a single sink, where energy conservation is often a concern, simulations of the new algorithms show as much as 80% of the transmit energy required to broadcast data can be saved, relative to existing OLA-based broadcasting approaches. In MANETs, where robustness of the routes is an important performance indicator, OLAROAD-based cooperative routes last much longer compared to their state-of-art multi-hop non-cooperative transmission (CT)-based counterparts. However, OLACRA and OLAROAD have higher node participation, and thereby lower throughput, in comparison with the non-CT schemes. To improve the throughput, and thereby bandwidth utilization, the properties of uplink OLAs and their suppression regions are carefully studied. Based on the observations, Hop-Optimized OLACRA (HOLA), which is a variant of OLACRA, and has the maximum bandwidth utilization amongst all the OLA unicast schemes studied, is proposed. HOLA routes have bandwidth utilization comparable to non-CT schemes, but a much lower (~10 dB less) transmit power per node.
The last section of this thesis treats the MAC design for OLA-based networks. In contrast to non-CT networks, a 802.11-based RTS/CTS MAC scheme is shown to reduce the reliability in OLA unicast schemes. A distributed cluster-head-based MAC scheme for channel reservation and OLA Size Adaptation Mechanism for link repair/maintenance are proposed for OLA-based networks. The performances of these protocols are shown to be comparable to a non-CT multihop scheme using the RTS/CTS/DATA/ACK handshake-based link layer design.
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Roy, Mousumi. "Front-end considerations for next generation communication receivers." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/frontend-considerations-for-next-generation-communication-receivers(636dc047-7772-46c3-b049-183d3af2a7bb).html.
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The ever increasing diversity in communication systems has created a demand for constant improvements in receiver components. This thesis describes the design and characterisation of front-end receiver components for various challenging applications, including characterisation of low noise foundry processes, LNA design and multi-band antenna design. It also includes a new theoretical analysis of noise coupling in low noise phased array receivers.In LNA design much depends on the choice of the optimum active devices. A comprehensive survey of the performance of low noise transistors is therefore extremely beneficial. To this end a comparison of the DC, small-signal and noise behaviours of 10 state-of-the-art GaAs and InP based pHEMT and mHEMT low noise processes has been carried out. Their suitability in LNA designs has been determined, with emphasis on the SKA project. This work is part of the first known detailed investigation of this kind. Results indicate the superiority of mature GaAs-based pHEMT processes, and highlight problems associated with the studied mHEMT processes. Two of the more promising processes have then been used to design C-band and UHF-band MMIC LNAs. A new theoretical analysis of coupled noise between antenna elements of a low noise phased array receiver has been carried out. Results of the noise wave analysis, based on fundamental principles of noisy networks, suggest that the coupled noise contribution to system noise temperatures should be smaller than had previously been suggested for systems like the SKA. The principles are applicable to any phased array receiver. Finally, a multi-band antenna has been designed and fabricated for a severe operating environment, covering the three extremely crowded frequency bands, the 2.1 GHz UMTS, the 2.4 GHz ISM and the 5.8 GHz ISM bands. Measurements have demonstrated excellent performance, exceeding that of equivalent commercial antennas aimed at similar applications.
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Morys, Marcin M. "Patch antenna characterization in a high-voltage corona plasma." Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50324.
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In order to improve efficiency and reliability of the world's power grids, sensors are being deployed for constant status monitoring. Placing inexpensive wireless sensors on high-voltage power lines presents a new challenge to the RF engineer. Large electric field intensities can exist around a wireless sensor antenna on a high-voltage power line, leading to the formation of a corona plasma. A corona plasma is a partially ionized volume of air formed through energetic electron-molecule collisions mediated by a strong electric field. This corona can contain large densities of free electrons which act as a conducting medium, absorbing RF energy and detuning the sensor's antenna.
Through the use of low-profile antennas and rounded geometries, the possibility for corona formation on the antenna surface is greatly reduced, as compared with wire antennas. This study looks at the effects of a corona plasma on a patch antenna, which could be used in a power line sensor. The corona's behavior in the presence of an electromagnetic plane wave is analyzed mathematically to understand the dependence of attenuation on frequency and electron density. A Drude model is used to convert plasma parameters such as electron density and collision frequency to a complex permittivity that can be incorporated in antenna simulations.
Using CST Microwave Studio, a 5.8 GHz patch antenna is simulated with a plasma material on its surface, of varying densities and thicknesses. Power absorption by the plasma dominates the power loss, as opposed to detuning. A wideband patch is simulated to show that the detuning effects by the plasma can be further reduced. Power absorption by the plasma is significant for electron densities greater than 10¹⁸ m⁻³. However, small point corona are found to have little effect on antenna radiation.
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Jung, Haejoon. "Experimentation and physical layer modeling for opportunistic large array-based networks." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/51798.
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The objective of this dissertation is to better understand the impact of the range extension and interference effects of opportunistic large arrays (OLAs), in the context of cooperative routing in multi-hop ad hoc networks. OLAs are a type of concurrent cooperative transmission (CCT), in which the number and location of nodes that will participate in a particular CCT cannot be known a priori. The motivation of this research is that the previous CCT research simplifies or neglects significant issues that impact the CCT-based network performance. Therefore, to develop and design more efficient and realistic OLA-based protocols, we clarify and examine through experimentation and analysis the simplified or neglected characteristics of CCT, which should be considered in the network-level system design. The main contributions of this research are (i) intra-flow interference analysis and throughput optimization in both disk- and strip-shaped networks, for multi-packet OLA transmission, (ii) CCT link modeling focusing on path-loss disparity and link asymmetry, (iii) demonstration of CCT range-extension and OLA-based routing using a software-defined radio (SDR) test-bed, (iv) a new OLA-based routing protocol with practical error control algorithm. In the throughput optimization in presence of the intra-channel interference, we analyze the feasibility condition of spatially pipelined OLA transmissions using the same channel and present numerical results with various system parameters. In the CCT link model, we provide the impact of path-loss disparity that are inherent in a virtual multiple-input-single-output (VMISO) link and propose an approximate model to calculate outage rates in high signal-to-noise-ratio (SNR) regime. Moreover, we present why link asymmetry is relatively more severe in CCT compared to single-input-single-output (SISO) links. The experimental studies show actual measurement values of the CCT range extension and realistic performance evaluation of OLA-based routing. Lastly, OLA with primary route set-up (OLA-PRISE) is proposed with a practical route recovery technique.
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Viteri, Mera Carlos Andres. "Beamforming Techniques for Frequency-Selective and Millimeter-Wave Indoor Broadcast Channels." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu152344603415358.
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Ibbotson, Alex. "The design and analysis of a rotman lens with reduced conjugate-port coupling." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/71799.
Full textAbstract:
Thesis (MScEng)--Stellenbosch University, 2012.<br>ENGLISH ABSTRACT: This project comprises the design, analysis, and construction of a Rotman lens with
reduced conjugate-port coupling. The Rotman lens is a beam-forming network, used
in wide-angle scanners to feed an antenna array. The scanning operation is based on
optics and is therefore frequency invariant, a desirable feature of the Rotman lens
compared to other beam-forming networks which employ phase shifters.
The antenna array is connected to the lens's array ports via transmission lines.
These array ports lie on the array contour which is designed so that a signal incident
onto the antenna array will propagate into the lens and focus at a particular point.
The position of this focal point depends on the signals direction of arrival at the
array. Ports are placed on these focal points to feed and receive signals. Bootlace
lenses allow up to four focal points for linear arrays whereas the Rotman lens is
designed for three foci. Scanners usually require to scan many beam-widths, thus
ports are employed along a focal arc which intersect these foci. Inter-focal ports do
not focus perfectly and result in phase errors distributed across the array aperture.
The derivation of three and four foci lenses is provided. There are several degrees
of freedom at the designer's disposal, the e ect which these available parameters have
on the lens geometry and phase errors is investigated. The waveguide implementa-
tion of these lenses is examined, in which we use vertically polarised horns as feed
ports and coaxial probes as array ports.
Some designs of Rotman lenses published in literature show excess mutual cou-
pling between symmetrically opposed feed ports. Using a model which approximates
the array contour as a re
ecting wall, we show that this is due to the re
ected energy
focusing on conjugate ports. It is identi ed that Rotman lenses designed for mini-
mum phase errors will have near maximum conjugate-port coupling. Two Rotman lenses have been designed at 3; 5GHz for ve feed ports, eleven
elements, and up to 30 scan angles. The rst is designed for minimum phase
errors, and the second for the defocusing of the re
ected energy from the focal
arc. Simulations show up to a 10dB reduction in conjugate-port coupling for the
second lens with a negligible degradation in performance from the phase errors.
Measurements show that the re
ected energy is spread between the feed ports as
expected, compared to the focusing at a single port of the traditional Rotman lens.<br>AFRIKAANSE OPSOMMING: Hierdie projek behels die ontwerp, analise en konstruksie van 'n Rotmanlens met
verminderde simmetries oorstaande poort koppeling. Die Rotmanlens is 'n patroon-
vormingsnetwerk wat gebruik word as samestellingvoer in wye hoek skandeerders.
'n Gewensde eienskap van die Rotmanlens bo faseskuif voernetwerke is dat die skan-
deerwerking gebasseer is op optika en dus frekwensie onafhanklik is.
Die antennasamestelling word deur transmissielyne verbind aan die antennapoorte
van die lens. Hierdie poorte l^e op die samestellingkontoer wat ontwerp is om te
verseker dat seine wat inval op die antennasamestelling sal voortplant in die lens en
fokus op 'n spesi eke punt. Die posisie van die fokuspunt hang af van die invalshoek
van die sein op die samestelling. Poorte word op hierdie fokuspunte geplaas om te
seine te ontvang en te lanseer. Hierdie tipe lense kan tot vier fokuspunte h^e , waar
die Rotman lens spesi ek vir drie fokuspunte ontwerp word. Skandeerders moet
normaalweg etlike bundelwydtes wyd kan skandeer, en daarom word poorte geplaas
op 'n straal wat die fokuspunte onderskep. Poorte wat weg van die fokus geplaas
word toon 'n e ens uit fokus gedrag, wat vertaal na fasefoute in die samestelling
stralingsvlak.
Die a
eiding van drie en vier fokus lense word verskaf. Daar is verskeie grade
van vryheid tot die beskikking van die ontwerper, en die e ek wat die beskikbare
parameters op die geometrie van die lens en die fase foute het word ondersoek. Die
gol
eier implimetering van hierdie lense word beskryf, waar vertikaal gepolariseerde
horings as voerpoorte, en ko-aksiale lyne as antennapoorte gebruik word. Sommige Rotman lens ontwerpe in die literatuur toon beduidende koppeling
tussen die simmetries oorstaande voerpoorte. Deur van 'n model gebruik te maak
wat die samestellingkontoer as 'n weerkaatsende muur benader toon ons aan dat
die koppeling geskied as gevolg van die weerkaatsde energie wat fokus in die simme-
tries oorstaande poorte. Dit word identi seer dat Rotman lense wat vir minimum
fasefoute ontwerp word bykans maksimum koppeling tussen simmetries oorstaande
poorte tot gevolg het.
Twee Rotman lense is ontwerp by 3; 5GHz vir vyf voerpoorte, elf antenna ele-
mente en skandeer hoeke van 30. Die eerste is ontwerp vir minimum fasefoute en
die tweede vir uit fokus weerkaatsde energie vanuit die fokus straal. Simulasies toon tot 10 dB vermindering in koppeling tussen simmetries oorstaande poorte vir die
tweede lens met weglaatbare werkverrigting verswakking as gevolg van fasefoute.
Metings toon dat die weerkaatsde energie, soos verwag, versprei word tussen die
voerpoorte vergeleke met energie gefokus in 'n enkele poort soos by die tradisionele
Rotman lens.
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JAIN, VIVEK. "ON-DEMAND MEDIUM ACCESS IN HETEROGENEOUS MULTIHOP WIRELESS NETWORKS." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1177508938.
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Rida, Amin H. "Conductive inkjet printed antennas on flexible low-cost paper-based substrates for RFID and WSN applications." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/28083.
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Thesis (M. S.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2009.<br>Committee Chair: Dr. Manos Tentzeris; Committee Member: Dr. Gregory Durgin; Committee Member: Dr. Joy Laskar.
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Khalil, Khaled. "Investigation, design and implementation of circular-polarised antennas for satellite mobile handset and wireless communications : simulation and measurement of microstrip patch and wire antennas for handheld satellite mobile handsets and investigations of polarization polarity, specific absorption rate, and antenna design optimization using genetic algorithms." Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/4319.
Full textAbstract:
The objectives of this research work are to investigate, design and implement circularly-polarized antennas to be used for handheld satellite mobile communication and wireless sensor networks. Several antennas such as Quadrifilar Spiral Antennas (QSAs), two arm Square Spiral and stripline or coaxially-fed microstrip patch antennas are developed and tested. These antennas are investigated and discussed to operate at L band (1.61-1.6214GHz) and ISM band (2.4835-2.5GHz) A substantial size reduction was achieved compared to conventional designs by introducing special modifications to the antenna geometries. Most of the antennas are designed to produce circularly-polarized broadside-beam except for wireless sensor network application a circularly-polarized conical-beam is considered. The polarization purity and Specific Absorption Rate (SAR) of two dual-band antennas for satellite-mobile handsets next to the human head are investigated and discussed, using a hybrid computational method. A small distance between the head and the handset is chosen to highlight the effects of the relatively high-radiated power proposed from this particular antenna. A Genetic Algorithm in cooperation with an electromagnetic simulator has been introduced to provide fast, accurate and reliable solutions for antenna design structures. Circularly-polarized quadrifilar helical antenna handset and two air-dielectric microstrip antennas were studied. The capabilities of GA are shown as an efficient optimisation tool for selecting globally optimal parameters to be used in simulations with an electromagnetic antenna design code, seeking convergence to designated specifications. The results in terms of the antenna size and radiation performance are addressed, and compared to measurements and previously published data.
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Seneviratne, Vishwa. "Design and Rapid-prototyping of Multidimensional-DSP Beamformers Using the ROACH-2 FPGA Platform." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1488149940846702.
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Araújo, Sandro Roberto de. "Diversidade de antena em redes de sensores sem fio industriais como técnica para aumento da confiabilidade." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/183315.
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Este trabalho concentra-se no aumento da robustez à taxa de erros em redes de sensores sem fio industriais (RSSFI). Para alcançar tal objetivo, é preciso, de algum modo, contornar os problemas intrínsecos da comunicação sem fio, que são, o ruído ambiental, interferências e desvanecimento por multipercurso. O multipercurso pode ser considerado um dos principais fatores que tornam as comunicações nas redes de sensores sem fio (RSSF) um verdadeiro desafio quando comparadas com outros meios, como a transmissão em fibra óptica, cabo ou mesmo transmissões de rádio ponto-a-ponto. Nesse sentido, propõe-se a diversidade de antenas como uma solução para minimizar os efeitos do multicaminho, com o objetivo de melhorar a confiabilidade do enlace de rádio para permitir o emprego de RSSF densas. O potencial da diversidade de antenas em RSSF não está totalmente explorado em aplicações industriais. Esta dissertação apresenta ainda, a técnica “Combinação de seleção” para RSSFI através de um algoritmo que seleciona a porta do receptor que apresenta o melhor indicador de qualidade de enlace e realiza a comutação das antenas nos módulos de rádio. Os resultados são analisados para dois tipos de enlaces, isto é, com e sem diversidade de antenas na recepção, e discute-se opções para melhorar o PER (“Packet Error Rate”) com as atuais técnicas de diversidade.<br>This work concentrates on the increase of reliability and robustness in Industrial Wireless Sensor Networks (IWSNs), decreasing the Packet Error Rate (PER). To achieve this objective, is need to somehow circumvent and reduce the underlying problems of wireless communication, which are: environmental noise, interference, and multipath fading. The multipath can be seen as the main factor which becomes the communications in the Wireless Sensor Networks (WSNs) a real challenge when compared to other types of means such as a transmission in fiber, cable or even point-to-point radio transmissions. In this sense, it is proposed antenna diversity as solution to reduce these effects, with the aim to improve the reliability of the radio link to allow the use of dense WSNs. The potential of antenna diversity in WSN is not fully exploited in industrial applications. In this sense, this dissertation presents the "Combination of selection" technique for IWSNs through an internal algorithm that selects the receiver port that has the highest LQI ("Link Quality Indicator") and performs an antenna switching in the radio modules. Also, options to improve PER using diversity techniques are discussed.
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Ortman, Robert L. "Sensory input encoding and readout methods for in vitro living neuronal networks." Thesis, Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/44856.
Full textAbstract:
Establishing and maintaining successful communication stands as a critical prerequisite for achieving the goals of inducing and studying advanced computation in small-scale living neuronal networks. The following work establishes a novel and effective method for communicating arbitrary "sensory" input information to cultures of living neurons, living neuronal networks (LNNs), consisting of approximately 20 000 rat cortical neurons plated on microelectrode arrays (MEAs) containing 60 electrodes. The sensory coding algorithm determines a set of effective codes (symbols), comprised of different spatio-temporal patterns of electrical stimulation, to which the LNN consistently produces unique responses to each individual symbol. The algorithm evaluates random sequences of candidate electrical stimulation patterns for evoked-response separability and reliability via a support vector machine (SVM)-based method, and employing the separability results as a fitness metric, a genetic algorithm subsequently constructs subsets of highly separable symbols (input patterns). Sustainable input/output (I/O) bit rates of 16-20 bits per second with a 10% symbol error rate resulted for time periods of approximately ten minutes to over ten hours. To further evaluate the resulting code sets' performance, I used the system to encode approximately ten hours of sinusoidal input into stimulation patterns that the algorithm selected and was able to recover the original signal with a normalized root-mean-square error of 20-30% using only the recorded LNN responses and trained SVM classifiers. Response variations over the course of several hours observed in the results of the sine wave I/O experiment suggest that the LNNs may retain some short-term memory of the previous input sample and undergo neuroplastic changes in the context of repeated stimulation with sensory coding patterns identified by the algorithm.
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Zemmour, Hamadache. "Réseaux de capteurs sans fil enfouis ultra large bande : antenne et liens radios." Thesis, Paris Est, 2016. http://www.theses.fr/2016PESC1076/document.
Full textAbstract:
Les réseaux de capteurs sans fils enfouis (RCSFE) sont des réseaux comportant des capteurs et leurs antennes enfouis dans la matière, en particulier enfouis dans le sol. Ils présentent un grand intérêt dans de nombreux domaines d’activités, comme le contrôle de l’environnement, l’agriculture de précision, la navigation et la sécurité. Les systèmes existants sont à bandes étroites et fonctionnent à des fréquences inférieures à 1 GHz. Ces systèmes impliquent l’utilisation d’antennes encombrantes, ce qui complique leur déploiement et peut conduire à des coûts élevés. De plus l’utilisation de largeurs de bandes étroites limite les débits de communications possibles et la résolution envisageables dans les applications de localisation. Enfin, les systèmes actuels sont gourmands en énergie, ce qui limite la durée de vie des éléments enfouis.Pour remédier à ces inconvénients pour certaines applications des RCSFE, on propose dans cette thèse d’utiliser la technique ultralarge bande (ULB) en bande normalisée 3,1 – 10,6 GHz dans les RCSFE. Cette technique permet l’utilisation d’antennes compactes, la simplification du déploiement, l’amélioration de la précision de localisation et l’augmentation du débit de communication et de la durée de vie des capteurs.Pour étudier la faisabilité des RCSFE ULB, nous avons conçu et réalisé trois antennes ULB compactes et en analyser l’effet du sol sur les performances de ces antennes ULB enfouies et sur les liens de communication ULB enfoui. En comparaison à un fonctionnement dans l’air, l’enfouissement dans le sol décale la bande passante de l’antenne vers les basses fréquences. Ce décalage augmente avec la teneur en eau du sol. L’atténuation apportée par le canal ULB enfoui augmente avec la fréquence de fonctionnement, la profondeur d’enfouissement et la teneur en eau du sol. Cependant, nous avons montré que des liaisons fiables sont possibles pour des distances de propagation dans le sol inférieures à 30 cm et des teneurs en eau inférieures à 20%<br>Wireless underground sensor networks (WUSN) consist of sensors which are buried in a medium with their antennas, in particular in soil. They attract a huge interest in different fields, like environment monitoring, precise agriculture, navigation and security. The existing narrowband systems operate at frequencies below 1 GHz. These systems imply the use of cumbersome antennas, which complicates the deployment and increases its cost. Furthermore, the use of narrow bandwidths limits the possible communication data rates and the potential resolution in localization applications. Finally, current systems are very energy consuming, which limits the lifetime of the underground elements.To overcome these drawbacks for certain applications of WUSN, we propose in this thesis the use of ultra wideband technology (UWB), in the normalized band 3.1 - 10.6 GHz, in WUSN. This technique allows the use of compact antennas, simplifying deployment, improving the localization accuracy and increasing communication data rates and the lifetime of the underground sensors.In order to assess the feasibility study of UWB WUSN, we have designed and realized three compact UWB antennas and analyzed the effect of soil on the performances of these underground UWB antennas and on the underground UWB communication links. Compared with operating in free space, burying the antenna shifts the antenna bandwidth towards low frequencies. This shift increases with soil water content. The attenuation introduced by the buried UWB channel, increases with the operating frequency, the burial depth and the soil moisture. However, we have shown that reliable communications are possible for distances of propagation in soil smaller than 30 cm and soil water contents below 20%
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Zheng, Kai-Zhao, and 鄭楷照. "Fingerprinting Localization with Cross Directional Antenna Arrays for Wireless Sensor Networks." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/72535977078171279372.
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碩士<br>國立中央大學<br>資訊工程學系<br>101<br>Fingerprinting method measures the radio signal patterns at certain location in the environment in an offline phase, and it localizes target devices according the similarity between current signal pattern and prior collected patterns. Directional antenna can distinguish the signal strength from different angle of arrival (AoA) based on its individual power gain for different directions. This paper presents a localization method for wireless sensor networks (WSNs), which using fingerprinting and directional antenna, called FLCDAA (Fingerprinting Localization with Cross Directional Antenna Arrays for WSNs). We set four directional antennas be cross arrangement at location-known anchor nodes, which an anchor node can independently localize its neighboring location-unknown target nodes. In offline phase, we measures and records the received signal strength indicator (RSSI) value which an anchor node receives a signal emitted from target node at different distances and angles, we store 4-tuple RSSI value as the radio pattern of antennas. In online phase, anchor node compares the RSSI values of signal emitted from target node with prior collected patterns for finding the best match one to estimate the related location of the sensor node corresponding to the anchor node. Furthermore, FLCDAA presents an accelerating method, performing linear regression to generating approximation functions to fit the AoA and RSSI-Difference value of any two vertical antennas in an anchor, and we use the approximation functions to reduce amount of pattern compared in online phase. We have to implemented an anchor of FLCDAA in a circular area with a radius of 6 meters within a indoor gym, we gather 100 patterns at each measuring position, take half of patterns be training data and the other half be the test data. The experiment average error is 24 centimeters for base method。In order to apply in bigger area, and try to train one antenna to replace other same type antennas to reduce training cost for scalability.
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Li, Zh-Jian, and 李誌堅. "Applying FD-MOGA to Deploy Wireless Sensor Network with Antenna Arrays." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/66183535594158964583.
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碩士<br>中華大學<br>資訊工程學系碩士班<br>100<br>Deploying a wireless sensor network (WSN) considering multiple objective cost functions and environment constraints is an important issue in real-world WSN applications. In many previous studies, a circle or a sphere is usually used to approximate the radiation pattern of a WSN node. However, many obstacles may block signals of WSN in outdoor environments. Therefore, some recent WSN studies adopted antenna array in designing their sensor nodes. Nevertheless, no study investigates how to deploy WSNs using antenna array. In this paper, Cassini oval is used to approximate radiation pattern of antenna array. A force-driven genetic algorithm is used to solve multi-objective deployment problems in differentiated wireless sensor network (WSNs), considering three optimization goals: coverage, detection satisfaction and energy consumption. Our experimental results demonstrated that the proposed approach is capable of obtaining a set of non-dominated solutions for multi-objective differentiated WSN deployment problems using antenna array.
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Upadrashta, Raviteja. "Design and Development of a Passive Infra-Red-Based Sensor Platform for Outdoor Deployment." Thesis, 2017. http://etd.iisc.ernet.in/2005/3439.
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This thesis presents the development of a Sensor Tower Platform (STP) comprised of an array of Passive Infra-Red (PIR) sensors along with a classification algorithm that enables the STP to distinguish between human intrusion, animal intrusion and clutter arising from wind-blown vegetative movement in an outdoor environment. The research was motivated by the aim of exploring the potential use of wireless sensor networks (WSNs) as an early-warning system to help mitigate human-wildlife conflicts occurring at the edge of a forest.
While PIR sensors are in commonplace use in indoor settings, their use in an outdoor environment is hampered by the fact that they are prone to false alarms arising from wind-blown vegetation. Every PIR sensor is made up of one or more pairs of pyroelectric pixels arranged in a plane, and the orientation of interest in this thesis is one in which this plane is a vertical plane, i.e., a plane perpendicular to the ground plane. The intersection of the Field Of View (FOV) of the PIR sensor with a second vertical plane that lies within the FOV of the PIR sensor, is called the virtual pixel array (VPA). The structure of the VPA corresponding to the plane along which intruder motion takes place determines the form of the signal generated by the PIR sensor. The STP developed in this thesis employs an array of PIR sensors designed so as to result in a VPA that makes it easier to discriminate between human and animal intrusion while keeping to a small level false alarms arising from vegetative motion. The design was carried out in iterative fashion, with each successive iteration separated by a lengthy testing phase. There were a total of 5 design iterations spanning a total period of 14 months.
Given the inherent challenges involved in gathering data corresponding to animal intrusion, the testing of the SP was carried out both using real-world data and through simulation. Simulation was carried out by developing a tool that employed animation software to simulate intruder and animal motion as well as some limited models of wind-blown vegetation. More specifically, the simulation tool employed 3-dimensional models of intruder and shrub motion that were developed using the popular animation software Blender. The simulated output signal of the PIR sensor was then generated by calculating the area of the 3-dimensional intruder when projected onto the VPA of the STP. An algorithm for efficiently calculating this to a good degree of approximation was implemented in Open Graphics Library (OpenGL). The simulation tool was useful both for evaluating various competing design alternatives as well as for developing an intuition for the kind of signals the SP would generate without the need for time-consuming and challenging animal-motion data collection.
Real-world data corresponding to human motion was gathered on the campus of the Indian Institute of Science (IISc), while animal data was recorded at a dog-trainer facility in Kengeri as well as the Bannerghatta Biological Park, both located in the outskirts of Bengaluru. The array of PIR sensors was designed so as to result in a VPA that had good spatial resolution. The spatial resolution capabilities of the STP permitted distinguishing between human and animal motion with good accuracy based on low-complexity, signal-energy computations. Rejecting false alarms arising from vegetative movement proved to be more challenging. While the inherent spatial resolution of the STP was very helpful, an alternative approach turned out to have much higher accuracy, although it is computationally more intensive. Under this approach, the intruder signal, either human or animal, was modelled as a chirp waveform. When the intruder moves along a circular arc surrounding the STP, the resulting signal is periodic with constant frequency. However, when the intruder moves along a more likely straight-line path, the resultant signal has a strong chirp component. Clutter signals arising from vegetative motion does not exhibit this chirp behavior and an algorithm that exploited this difference turned in a classification accuracy in excess of 97%.
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Roque, Justin. "Dynamic adaptable antenna arrays for wireless communication networks." Thesis, 2006. http://hdl.handle.net/10125/20558.
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