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1
Sheret, Tamara Louise. "Design, analysis and validation of a twist reflector monopulse antenna system with radome." Thesis, Queen Mary, University of London, 2017. http://qmro.qmul.ac.uk/xmlui/handle/123456789/24740.
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This thesis presents a new approach to the hardware test environment for a twist reflector monopulse antenna system with a radome extending current measurement practice. New research is presented on the optimisation of the design of a twist reflector monopulse antenna system with a radome, significantly improving the design and the design process. A unique extension to current measurement practice, for single channel antennas, is presented to determine the best practice method on phase stable measurements of a multi-channel antenna on a moving positioner. A novel axis transform for a 3 axis positioner system located within an anechoic chamber is derived. It allows for true performance measurement of a twist reflector antenna with a radome. This progresses the field of antenna measurement as, uniquely, this axis transform allows the aberration caused by the antenna radome to be measured and included. Design improvements have been made on polarisation selective grids, the matched thickness of the radome and a new software method that removes the need for a comparator and increases the robustness of the antenna system. Polarisation selective grids, constructed from a set of parallel conductors, have a wide range of uses in antenna systems. This thesis shows that the depth of a copper grid line can be reduced to 15 m and still provide better than -25 dB cross-polar isolation. This is contrary to current understanding at 30 times the skin depth. A new combined approach to radome thickness optimisation is presented that reduces the time taken to calculate the optimal thickness by over 3 orders of magnitude and the computer memory by over 2 orders of magnitude without compromising accuracy. The use of a digital comparator is described and leads to a novel method to compensate for a failed feed element, verifified in both simulation and anechoic chamber measurements.
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Elloian, Jeffrey. "Theoretical and Numerical Analysis of a Novel Electrically Small and Directive Antenna." Digital WPI, 2014. https://digitalcommons.wpi.edu/etd-theses/105.
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Small antennas have attracted significant attention due to their prolific use in consumer electronics. Such antennas are highly desirable in the healthcare industry for imaging and implants. However, most small antennas are not highly directive and are detuned when in the presence of a dielectric. The human body can be compared to a series of lossy dielectric media. A novel antenna design, the orthogonal coil, is proposed to counter both of these shortcomings. As loop antennas radiate primarily in the magnetic field, their far field pattern is less influenced by nearby lossy dielectrics. By exciting two orthogonal coil antennas in quadrature, their beams in the H-plane constructively add in one direction and cancel in the other. The result is a small, yet directive antenna, when placed near a dielectric interface. In addition to present a review of the current literature relating to small antennas and dipoles near lossy interfaces, the far field of the orthogonal coil antenna is derived. The directivity is then plotted for various conditions to observe the effect of changing dielectric constants, separation from the interface, etc. Numeric simulations were performed using both Finite Difference Time Domain (FDTD) in MATLAB and Finite Element Method (FEM) in Ansys HFSS using a anatomically accurate high-fidelity head mesh that was generated from the Visible Human Project® data. The following problem has been addressed: find the best radio-frequency path through the brain for a given receiver position - on the top of the sinus cavity. Two parameters: transmitter position and radiating frequency should be optimized simultaneously such that (i) the propagation path through the brain is the longest; and (ii) the received power is maximized. To solve this problem, we have performed a systematic and comprehensive study of the electromagnetic fields excited in the head by the aforementioned orthogonal dipoles. Similar analyses were performed using pulses to detect Alzheimer’s disease, and on the femur to detect osteoporosis.
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LIU, HUAZHOU. "DIGITAL DIRECTION FINDING SYSTEM DESIGN AND ANALYSIS." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1060976413.
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Civerolo, Michael Paul. "Aperture Coupled Microstrip Antenna Design and Analysis." DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/300.
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A linearly-polarized aperture coupled patch antenna design is characterized and optimized using HFSS antenna simulation software. This thesis focuses on the aperture coupled patch antenna due to the lack of fabrication and tuning documentation for the design of this antenna and its usefulness in arrays and orthogonally polarized communications. The goal of this thesis is to explore dimension effects on aperture coupled antenna performance, to develop a design and tuning procedure, and to describe performance effects through electromagnetic principles.
Antenna parameters examined in this study include the dimensions and locations of the substrates, feed line, ground plane coupling slot, and patch. The operating frequency, input VSWR, percent bandwidth, polarization ratio, and broadside gain are determined for each antenna configuration.
The substrate material is changed from RT Duroid (material in nominal HFSS design) to FR4 due to lower cost and availability. The operating frequency is changed from 2.3GHz (specified in nominal HFSS design) to 2.4GHz for wireless communication applications. Required dimensional adjustments when changing substrate materials and operating frequencies for this antenna are non-trivial and the new design procedure is used to tune the antenna.
The antenna is fabricated using 59mil thick double and single sided FR4 boards joined together with double sided 45mil thick acrylic tape. The antenna is characterized in an anechoic chamber and experimental results are compared to theoretical predictions. The results show that the new design procedure can be successfully applied to aperture coupled antenna design.
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Tasoglu, Ali Ozgur. "Analysis And Design Of Cylindrically Conformal Microstrip Antennas." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613441/index.pdf.
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Cylindrically conformal microstrip antennas are investigated. Two different structures, namely proximity coupled and E-shaped microstrip antennas are analyzed and information about the design parameters is obtained by means of parametric study. With these structures, cylindrical arrays, having omnidirectional radiation in the circumferential plane of the cylinder, are designed. Proximity coupled cylindrical arrays operate in the 2.3-2.4 GHz aeronautical telemetry band with approximately 4% bandwidth. On the other hand, more than 30% bandwidth is obtained by E-Shaped cylindrical array
antenna structure, which also includes the commercial telemetry band. In order to verify the simulation method, a fabricated antenna in literature is simulated and acceptable agreement with simulation and fabrication results obtained.
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Venugopal, Arvind. "Analysis and Design of Microstrip antenna for a Smart-antenna test-bed." NCSU, 2001. http://www.lib.ncsu.edu/theses/available/etd-20010806-202546.
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Small planar antennas are becoming increasingly popular in personal wireless communication systems since these antennas offer advantages such as small size,light weight, robust construction, ease of integration into mobile handsets, reasonable radiation efficiency and gain. A new small microstrip antenna operating at 880MHz is designed using the Finite difference time domain technique incorporating the perfectly matched-layer formulation. Shorting pins are used to achieve the reduction in size.The size of this patch antenna is approximately four times less than that of the regular half wavelength patch antenna. An antenna array made of the new patch antennas is used ina multiple antenna system to reliably separate different users on the same channel using linearbeam steering techniques with the ultimate goal of increasing the channel capacity.Prototypes of the proposed dual shorted-pin-patch antenna are fabricated and measurements of their return loss compare well with the computational results.
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Fatthi, Alsager Ahmed. "Design and Analysis of Microstrip Patch Antenna Arrays." Thesis, Högskolan i Borås, Institutionen Ingenjörshögskolan, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-20461.
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The performance and advantages of microstrip patch antennas such as lowweight, low profile, and low cost made them the perfect choice forcommunication systems engineers. They have the capability to integrate withmicrowave circuits and therefore they are very well suited for applications suchas cell devices, WLAN applications, navigation systems and many othersIn this thesis; a compact rectangular patch antennas are designed and tested forGPS devices at 1.57542 GHz, and for a satellite TV signal at 11.843 GHz and11.919 GHz. The final part of this work has been concentrated on studying anarray antenna with two and four elements. The antennas of the design examplesof this work has been manufactured and tested in laboratory.
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Tastan, Mehmet. "Analysis And Design Of A Circularly Polarized Microstrip Antenna." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12607868/index.pdf.
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In this study we tried to design a microstrip antenna, to get a suitable radiation pattern for a LEO satellite. Our aim is to get a radiation pattern that has a maximum power which is not in the broadside direction to the antenna surfaceinstead broadside radiation has a relatively lower power density. Maximum power radiation is desired to be at about 30 &ndash
50 degrees angle beyond the normal to the antenna surface. We desire circularly polarized radiation. We used two concentric antennas
one is a circular patch at the center and the other is an annular ring which is used at the outer region. By using Ansoft Ensemble 8.0 software, we design an antenna which has a resonance frequency at 8.2 GHz. Using the result of the program we design the real antenna. The measurement results are compared with the simulation results.
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Safin, Eugen [Verfasser]. "Modal analysis methods for small antenna design / Eugen Safin." Kiel : Universitätsbibliothek Kiel, 2017. http://d-nb.info/1123998159/34.
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Kirik, Mustafa Sancay. "Design, Analysis, And Implementation Of Circular Disk - Annular Ring (cdar) Antenna." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12609156/index.pdf.
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In satellite applications, a circularly polarized satellite antenna is desirable with a pattern that results in constant received power while the distance between the transmitter and the receiver is changing. The Circular Disk - Annular Ring (CDAR) antenna satisfies these requirements along with other requirements for the satellite antenna. The CDAR antenna is a combination of a Circular Disk and an Annular Ring patch antennas. In this thesis, a circularly polarized CDAR antenna that is fed from a single point is designed at the center frequency of 8.2 GHz. This antenna is investigated and optimized to ease the fabrication process. The design parameters are defined on this report and optimized by using an Electromagnetic Simulation software program. In order to verify the theoretical results, Circular Disk - Annular Ring Antenna is produced as a prototype. Measurements of antenna parameters, electromagnetic field and circuit properties are interpreted to show compliance with theoretical and simulation results. The values of deviation between theoretical and experimental results are also discussed.
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Magalhães, Marcelo Pereira. "Design and analysis of an antenna array system for communication using high-altitude platforms." Universidade Federal do Pampa, 2017. http://dspace.unipampa.edu.br:8080/jspui/handle/riu/1988.
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This thesis presents the design and analysis of an antenna array system for mobile communication services in a scenario using high altitude platforms (HAPs). For this purpose, a dual-band and dual-polarized microstrip antenna array has been designed, whereby the array should receive the signal in one band and resend it in the other operating band. These requirements have been fulfilled by using a stacked arrangement, whereby each patch has been fed by independent feed lines. Circular polarization was obtained by the use of square patches with truncated corners. Optimizations were needed so as to compensate the effects of mutual coupling on the axial ratio level. To perform the radiation pattern synthesis for the transmission function, an algorithm to calculate the required excitation coefficients was employed to steer the main beam and to control the side lobe level. Additionally to the array design, the development of the high-frequency (HF) circuitry for the retransmission is described. The design of the transmitter was done using off-the-shelf components, which have been tested individually prior to the final integration into the final layout. During the tests, the need of knowledge of the electromagnetic properties of the printed circuit layout and the active/passive components is crucial for a successful design. In order to accelerate the development of HF circuitry, a procedure to perform electromagnetic simulations of HF printed circuit boards is proposed. Experimental results demonstrated that this procedure yielded accurate engineering predictions.
Este trabalho apresenta o projeto e análise de um sistema de rede de antenas para serviços de comunicações móveis em um cenário empregando plataformas de alta altitude (HAPs). Para este fim, uma rede de antenas de microfita foi projetada para operar em dupla-banda e dupla-polarização, onde a rede deve receber o sinal em uma banda e reenviá-lo em outra. Esses requisitos foram cumpridos usando uma rede de antenas com m´ultiplas camadas, onde cada patch foi alimentado por linhas de alimentação independentes. A polarização circular foi obtida pelo uso de patches quadrados com os cantos truncados. Foram necessárias otimizações para compensar os efeitos de acoplamento mútuo no nível da razão axial. Para realizar o controle do diagrama de irradiação para o modo de transmissão, utilizou-se um algoritmo para calcular os pesos necessários para apontar o lóbulo principal e controlar o nível dos lóbulos laterais. Adicionalmente ao projeto da rede, o desenvolvimento de um circuito em alta frequência (HF) para a retransmissão foi descrito. O projeto do circuito transmissor foi realizado empregando componentes comerciais, que foram testados individualmente antes da integração final. Durante os testes em bancada, ficou evidente a necessidade de predição do comportamento eletromagnético do layout da placa de circuito impresso e dos componentes ativos/passivos para obtenção de bons resultados. Com o intuito de acelerar o processo de desenvolvimento de circuitos em HF, um procedimento para a realização de simulações eletromagnéticas de placas de circuito impresso foi proposto. Os resultados experimentais demonstraram que este procedimento produziu bons resultados.
12
Surittikul, Nuttawit. "Pattern reconfigurable printed antennas and time domain method of characteristic modes for antenna analysis and design." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1143225860.
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Elfrgani, Aseim M. N. "Non-Foster Circuit Design and Stability Analysis for Wideband Antenna Applications." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1431109155.
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Dahal, Robi, and Demet Mercan. "Design and performance analysis of purely textile antenna for wireless applications." Thesis, Högskolan i Gävle, Avdelningen för elektronik, matematik och naturvetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-11521.
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This thesis work is concerned with the design and performance analysis of purely textile antenna for wireless applications. The materials used for radiating element, ground plane and dielectric substrate are purely textile. Two types of antennas are studied, the microstrip patch antenna and RFID tag antenna. Each type of antenna is designed and fabricated using two different conductive textile materials as radiating element. The radiating element and ground plane of conventional printed antenna is manufactured with the metal plating on a solid dielectric substrate. The radiating element which is used in this thesis work has different characteristics as compared to printed antenna because it is made of conductive textile material which is less conductive than metal and elastic in nature. Each conductive textile material has different surface resistivity. The study has been made to analyze the effect on gain and radiation efficiency of the antenna when different conductive textile material is used as the radiating element. The measured results of the fabricated antennas present the full potential of conductive textile materials to be used as an antenna.
15
Ferland, Etienne. "Analysis and design of a synthetic aperture radar membrane antenna." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=95659.
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Use of a membrane antenna on remote sensing satellites is now possible because of new materials and manufacturing technologies. This would allow space organizations to cut cost and weight by a non-negligible factor. All possible failure modes must be fully analyzed before these are sent to space. With membrane antennas, a new type of failure mode must be looked at: wrinkling. The wrinkling of the emitting layer could greatly undermine the performance of the antenna by modifying the orientation of the radiating elements rendering the wrinkle-affected area useless. It has been anticipated that such wrinkling could occur under temperature variations in space. There is currently a lack of available analyses for predicting with confidence the behaviour of such stretched material in a space environment. This work develops and establishes a finite-element approach as a potential method for predicting wrinkle height and orientation under thermal loads. Some designs for controlling the wrinkles are introduced with the benefits of optimizing the antenna area. The influence of the variation of the parabolic edges and corner cut-offs on the required cable load has been studied. Dynamic behaviour poses a concern, especially with a larger and flexible membrane and has been studied to determine the natural frequencies and the response of the antenna to on-orbit micro-vibrations .L'utilisation d'une antenne membrane sur les satellites de télédétection est désormais possible par la fabrication de nouveaux matériaux et le développement de nouvelles techniques manufacturières. Une telle antenne permettrait aux organisations possédant de tels satellites d'en réduire le poids et du fait même le coût de lancement par un facteur important. Toutes les causes d'échec, de panne ou d'insuccès reliées à l'utilisation d'une antenne membrane doivent être pleinement étudiées avant qu'elle ne soit lancée. Avec l'émergence de cette nouvelle technologie, une nouvelle problématique s'ajoute: le plissement. Le plissement de la membrane émettrice pourrait affecter l'efficacité del'antenne et réduire ses performances électriques en modifiant l'orientation des éléments radiatifs de la membrane rendant ainsi inopérante la région affectée. Les variations de température présentes dans l'espace peuvent produire de tels plissements. Très peu d'analyses sont disponibles pour prédire en toute certitude le comportement d'une telle membrane en orbite. Cette étude propose l'étude d'une approche par éléments finis analysant la hauteur et l'orientation des plissements dues aux variations de température. Le contrôle des ridules par méthode passive a été également étudié permettant l'optimisation de l'aire et des dimensions de la membrane. L'influence de la forme parabolique des cotés de la membrane sur la force axiale du câble de tension a été étudiée et est présentée. Le comportement dynamique de la membrane est l'objet d'une attention particulière étant donné sa propension à amplifier les micro vibrations . fr
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Duong, Ninh T. "Analysis and design of millimetre wave antenna array power combines /." Title page, table of contents and abstract only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phd925.pdf.
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Yan, Ming. "Antenna array receiver design and analysis in fast fading environments /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2001. http://wwwlib.umi.com/cr/ucsd/fullcit?p3022209.
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Caldwell, Dwight D. (Dwight Douglas). "Design and analysis of the ICRF antenna with active cooling." Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/42516.
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Torres, Roberto. "Analysis and design of a resistively coated windshield slot antenna /." The Ohio State University, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487693923196521.
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Liu, Chuan-Chang. "Design, Analysis and Implementation of Fully-Integrated Millimeter-Wave Coupled-Oscillator Antenna Array." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1452240824.
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Petersen, Lynn James. "Mast-antenna survivability : structural dynamic design analysis by component mode synthesis." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1994. http://handle.dtic.mil/100.2/ADA280669.
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Oudit, Suzanne Riggs Lloyd Stephen. "Design of an outdoor wireless local area network and antenna analysis." Auburn, Ala., 2006. http://repo.lib.auburn.edu/2006%20Summer/Theses/OUDIT_SUZANNE_45.pdf.
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Kokkinos, Titos. "Analysis and design of metamaterial-inspired microwave structures and antenna applications." Thesis, Loughborough University, 2010. https://dspace.lboro.ac.uk/2134/6094.
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Novel metamaterial and metamaterial-inspired structures and microwave/antenna applications thereof are proposed and studied in this thesis. Motivated by the challenge of extending the applicability of metamaterial structures into practical microwave solutions, the underlying objective of this thesis has been the design of low-cost, easily fabricated and deployable metamaterial-related devices and the development of computational tools for the analysis of those. For this purpose, metamaterials composed of tightly coupled resonators are chosen for the synthesis of artificial transmission lines and enabling antenna applications. Specifically, fully-printed double spiral resonators are employed as modular elements for the design of tightly coupled resonators arrays. After thoroughly investigating the properties of such resonators, they are used for the synthesis of artificial lines in either grounded or non-grounded configurations. In the first case, the supported backward waves are exploited for the design of microstrip-based filtering/diplexing devices and series-fed antenna arrays. In the second case, the effective properties of such structures are employed for the design of a novel class of self-resonant, low-profile folded monopoles, exhibiting low mutual coupling and robust radiating properties. Such monopoles are, in turn, used for the synthesis of different sub-wavelength antenna arrays, such as superdirective arrays. Finally, an in-home periodic FDTD-based computational tool is developed and optimized for the efficient and rigorous analysis of planar, metamaterial-based, high-gain antennas.
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Zhang, Qianyun. "Antenna design with characteristic mode analysis for Internet of Things applications." Thesis, Queen Mary, University of London, 2018. http://qmro.qmul.ac.uk/xmlui/handle/123456789/44699.
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The TV white space (TVWS) is one of the promising technologies to provide wide coverage, energy effcient and cost effective Internet of Things (IoT) services. However, its low operating frequency and wide bandwidth poses significant challenges to antenna designs. In this thesis, three antennas are developed using the characteristic mode analysis (CMA) for IoT devices operating over the TVWS. First, a very-low profile circular small antenna is transformed from a vertical monopole antenna. The CMA is used to determine the mode to be excited and to design a specific feeding structure. After being printed on Rogers 5880 substrate, the final antenna structure operates at 474 MHz with a V SWR < 2 bandwidth of 2.2 MHz. Its lateral radius is just 5.2% of the wavelength of its resonant frequency. Second, a compact U-shaped printed UWB monopole antenna is proposed to operate over the entire UHF TV spectrum. This antenna measures 0:36 0 0:06 0 0:01 0 where 0 is the wavelength of its lowest operating frequency. Its V SWR < 2 bandwidth is 87.5%, and the UWB behaviour is discussed by the CMA. Third, a novel antenna design method is established on annular ring-shaped structures with modal characteristics revealed by the CMA. Following the proposed method, another UWB antenna is achieved by creating and exciting multiple modes with resonant frequencies distributed across the UHF TV spectrum. All antenna designs are verified thorough simulations and measurements. Furthermore, antennas are also integrated into IoT devices and their system performance is measured under different communication scenarios. The system measurements also verify the good propagation property and the abundant spectrum resource of the TVWS.
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Sanudin, Rahmat. "Planar array design and analysis on direction of arrival estimation for mobile communication systems." Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/8992.
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The demand of wireless communication has increased significantly in the past few decades due to huge demand to deliver multimedia content instantly. The expansion of mobile content paired with affordable mobile devices has opened a new trend for having access to the latest information on mobile devices. This trend is made possible by the technology of smart antenna systems as well as array signal processing algorithms. Array signal processing is not limited to wireless communication, but also found in other applications such as radar, sonar and automotive. One of the important components in array signal processing is its ability to estimate the direction of incoming signals known as directional-of-arrival (DOA). The performance of DOA algorithms depends on the steering vector since it contains information about the direction of incoming signals. One of the main factors to affect the DOA estimation is the array geometries since the array factor of the array geometries determines the definition of the steering vector. Another issue in DOA estimation is that the DOA algorithms are designed based on the ideal assumption that the antenna arrays are free from imperfection conditions. In practice, ideal conditions are extremely difficult to obtain and thus the imperfect conditions will severely degraded the performance of DOA estimation. The imperfect conditions include the presence of mutual coupling between elements and are also characteristic of directional antenna. There are three topics being discussed in this thesis. The first topic being investigated is new geometry of antenna array to improve the performance of DOA estimation. Two variants of the circular-based array are proposed in this thesis: semi-circular array and oval array. Another proposed array is Y-bend array, which is a variant of V-shape array. The proposed arrays are being put forward to offer a better performance of DOA estimation and have less acquired area compared with the circular array. It is found out that the semi-circular array has 5.7% better estimation resolution, 76% lower estimation error, and 20% higher estimation consistency than the circular array. The oval array improves the estimation resolution by 33%, estimation error by 60%, and estimation consistency by 20% compared with the circular array. In addition, for the same number of elements, the oval array requires 12.5% to 15% less area than the circular array. The third proposed array, Y-bend array, has 23% smaller estimation resolution, 88% lower estimation error, and 7% higher estimation consistency than the V-shape array. Among the proposed arrays, the semi-circular possessed the best performance with 25% smaller estimation resolution, ten times smaller estimation error, and 5% higher estimation consistency over the other proposed arrays. Secondly, this thesis investigates the DOA estimation algorithm when using the directional antenna array. In this case, a new algorithm is proposed in order to suit the characteristics of the directional antenna array. The proposed algorithm is a modified version of the Capon algorithm, one of the algorithms in beamforming category. In elevation angle estimation, the proposed algorithm achieves estimation resolution up to 1°. The proposed algorithm also manages to improve the estimation error by 80% and estimation consistency by 10% compared with the Capon algorithm. In azimuth angle estimation, the proposed algorithm achieves 20 times lower estimation error and 20% higher estimation consistency than the Capon algorithm. These simulation results show that the proposed algorithm works effectively with the directional antenna array. Finally, the thesis proposes a new method in DOA estimation process for directional antenna array. The proposed method is achieved by means of modifying covariance matrix calculation. Simulation results suggest that the proposed method improves the estimation resolution by 5° and the estimation error by 10% compared with the conventional method. In summary, this thesis has contributed in three main topics related to DOA estimation; array geometry design, algorithm for the directional antenna array, and method in DOA estimation process for the directional antenna array.
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Garcia, Gamez Laura. "Analysis and design of compact antennas in cavity based on metasurfaces for multiband GNSS applications." Thesis, Rennes 1, 2020. http://www.theses.fr/2020REN1S014.
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Les systèmes de navigation par satellites globaux (GNSS) sont aujourd'hui largement utilisés pour pléthore d'applications civiles ou pour la défense, incluant la navigation de plateformes volantes ou roulantes. Galileo, GPS ou Glonass sont trois des constellations GNSS considérées dans cette thèse. L'objectif de ce travail est de développer des antennes compactes capables de couvrir plusieurs bandes GNSS ; trois autour de 1575 MHz dans un premier temps (L1, G1, E1), puis la totalité de la bande GNSS ([1164-1610] MHz). Ces antennes sont destinées à être intégrées dans des projectiles, constitués principalement de métal. Pour cette raison, l'antenne doit être intégrée dans une cavité métallique pour ne pas affecter les propriétés aérodynamiques ni la stabilité mécanique du porteur. Intégrer des antennes imprimées dans des cavités métalliques offre plusieurs avantages : la miniaturisation, l'isolation ou la réduction des ondes de surface. Néanmoins, cela amène également une réduction importante de la bande passante. La solution immédiate pour limiter cet effet est d'agrandir la dimension de la cavité. Cependant, cette approche ne peut pas être appliquée aux nombreux cas où le porteur impose des limitations d'encombrement. Au vu des spécifications ci-dessus, l'emploi d'une antenne imprimée basée de métasurfaces est proposé et étudié, d'autant plus que des résultats antérieurs ont montré que des structures d'antennes classiques ne peuvent répondre aux spécifications demandées. Les objectifs de cette thèse sont de concevoir et de caractériser des antennes à polarisation linéaire et à polarisation circulaire couvrant plusieurs bandes GNSS. La polarisation linéaire est considérée pour les premières études, car ces antennes ne sont pas destinées à être utilisées dans un environnement souffrant de trajets multiples. La polarisation circulaire est considérée dans un second temps. Finalement, l'extension de la bande passante à la globalité de la bande GNSS est considéréeGlobal Navigation Satellite Systems (GNSS) are widely used today for a plethora of civil and defense applications, including navigation of flying or moving platforms. Galileo, GPS or Glonass are three of the GNSS constellations considered in this thesis. The aim of this work is to develop a compact antenna, which is able to cover multiple GNSS bands: three around 1578 MHz (L1, G1, E1) in a first time and the whole band ([1164-1610] MHz) in a second time. These antennas are intended to be integrated into projectiles mainly constituted of metal. For this reason, the antenna must be embedded in a metallic cavity to not affect the carrier aerodynamic properties and nor its mechanical stability. Integrating microstrip antennas in metallic cavities offers several advantages, like miniaturization, isolation or surface wave reduction; however, this leads to a drastic reduction of the antenna bandwidth. The most straightforward solution to circumvent this limitation consist in enlarging the metal cavity size. Nonetheless, this approach cannot be applied in many cases when the carrier imposes stringent dimensional limitations. Owing to the above-mentioned specifications, the use of a metasurface-inspired microstrip antenna is proposed and investigated, since previous results have demonstrated that classical antenna structures do not comply with the requirements. The objectives of the thesis are to design and characterize linearly-polarized and circularly-polarized antennas covering multiple bands of GNSS. Linear polarization is considered for the first studies, as these antennas are not intended to be used in an environment with multi-path signals. Circular polarization is addressed in a second time. Finally, the extension of the bandwidth to the whole GNSS bands is considered
27
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.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.
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.
28
Wingfield, Alistair P. "Analysis and design of the twisted loop antenna topology for mobile communications." Thesis, Loughborough University, 2004. https://dspace.lboro.ac.uk/2134/14209.
Full textAbstract:
The handset product has been styled in successive years to reach more compact sizes and there has as a result been a reduction in volume available to house antennas; therefore size/performance trade-offs have had to become accommodated. Some of the issues antenna engineers are currently confronted with include; frequency shifting due to the antenna not being isolated from the handset, far field pattern deformation due to close proximity effects from the energy absorbing human tissues, distortion caused by noise from electronic components that share the handheld platform. What is required is antenna technology, which maintains a high enough performance despite the escalating restrictions imposed by the demands of the market. Research is performed on a twisted loop antenna topology that possesses an integral balun as part of its structure. Two rudimentary designs are utilised in the research, a simple bifilar structure that can be adapted for GSM, peN, Bluetooth and W-LAN applications, and a quadrifilar helix structure for use in GPS. Both structures are based on existing industrial dielectricloaded antenna structures but are modelled as novel air-loaded structures using a commercially available Method of Moments (MoM) electromagnetic simulator. In this fashion, the antennas could be generated quickly with low computational requirements. A parametric study is performed on the bifilar antenna structure to gain an enhanced understanding of the twisted loop topology. Once this understanding is achieved proposed modifications to the structure are implemented to improve the performance of the antenna. The main subject of improvement is the broadening of bandwidth as normally dielectric-loaded antennas have inherent narrow bandwidth. Any improvements made on the air-loaded structures could be tested on dielectric structures in future research. The most successful novel approach attempted to increase the bandwidth in the twisted loop structure was the insertion of parasitic helices to create a coupled multi-pole filter response. In conjunction with the work performed on the bifilar, an air-loaded GPS quadrifilar helix antenna was also modelled. A method for inducing circular polarisation is proposed and then by the insertion of parasitics into the quadrifilar helix design a novel dual-band dual-polarised antenna is presented. Finally measurements are made to demonstrate the advantageous properties the dielectric-loaded GPS antenna has over conventional GPS antennas.
29
Zhou, Min. "Design and time-domain analysis of antenna array for UWB imaging application." Thesis, Queen Mary, University of London, 2014. http://qmro.qmul.ac.uk/xmlui/handle/123456789/9117.
Full textAbstract:
UWB technology has been developing in imaging applications. For security imaging applications, it is vital to detect and image metallic targets concealed in bag at airports, subway stations or other public environments. To reduce the cost of the deployment of X-ray machines, a novel UWB imaging system has been developed, including the design of the UWB rotating antenna array, the design of RF circuits and the implementation of the two-dimensional delay-and-sum (DAS) image reconstruction method. Two types of UWB antennas, the circular-edge antipodal Vivaldi antenna and the corrugated balanced antipodal Vivaldi antenna (BAVA) have been designed and studied in both frequency domain and time domain. Both of them can work across UWB frequency range from 3.1 GHz to 10.6 GHz, and have directional radiation patterns. The corrugated BAVA with smaller physical size has been improved to have a relative high gain around 7 dBi across the operating frequency range. It also causes less distortion to signals in the time domain. So the corrugated BAVA is used as the antenna element in the UWB rotating antenna array. The UWB rotating antenna array comprises one central transmitting antenna and four receiving antennas. The receiving antennas, which rotate around the central transmitting antenna, are placed side-by-side on a straight arm. The equivalent antenna elements in space are increased by the rotation of the antenna array. The two-dimensional image reconstruction method has been developed based on DAS algorithm. This UWB imaging system can detect and reconstruct the image of the single and pairs of metallic targets concealed in bag. The smallest single target with the size of 4 cm × 4 cm × 1 cm can be reconstructed in images at a maximum distance of 30 cm away from the system. It can achieve 6 cm in cross-range resolution and 15 cm in down-range resolution. Therefore, the feasibility of the proposed UWB imaging system has been proved.
30
Aldosari, Mansour. "Design and analysis of green mobile communication networks." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/design-and-analysis-of-green-mobile-communication-networks(37b5278a-45da-4a81-b89c-54c7d876586a).html.
Full textAbstract:
Increasing energy consumption is a result of the rapid growth in cellular communication technologies and a massive increase in the number of mobile terminals (MTs) and communication sites. In cellular communication networks, energy efficiency (EE) and spectral efficiency (SE) are two of the most important criteria employed to evaluate the performance of networks. A compromise between these two conflicting criteria is therefore required, in order to achieve the best cellular network performance. Fractional frequency reuse (FFR), classed as either strict FFR or soft frequency reuse (SFR), is an intercell interference coordination (ICIC) technique applied to manage interference when more spectrum is used, and to enhance the EE. A conventional cellular model's downlink is designed as a reference in the presence of inter-cell interference (ICI) and a general fading environment. Energy-efficient cellular models,such as cell zooming, cooperative BSs and relaying models are designed, analysed and compared with the reference model, in order to reduce network energy consumption without degrading the SE. New mathematical models are derived herein to design a distributed antenna system (DAS), in order to enhance the system's EE and SE. DAS is designed in the presence of ICI and composite fading and shadowing with FFR. A coordinate multi-point (CoMP) technique is applied, using maximum ratio transmission (MRT) to serve the mobile terminal (MT), with all distributed antenna elements (DAEs), transmit antenna selection (TAS) being applied to select the best DAE and general selection combining (GSC) being applied to select more than one DAE. Furthermore, a Cloud radio access network (C-RAN) is designed and analysed with two different schemes, using the high-power node (HPN) and a remote radio head (RRH), in order to improve the EE and SE of the system. Finally, a trade-off between the two conflicting criteria, EE and SE, is handled carefully in this thesis, in order to ensure a green cellular communication network.
31
Barros, Pedro A. "Design and analysis of a folded meander dipole antenna using the MININEC program." FIU Digital Commons, 1991. http://digitalcommons.fiu.edu/etd/1428.
Full textAbstract:
The Mini-Numerical Electromagnetic Code (MININEC) program, a PC-Compatible version of the powerful NEC program, is used to design a new type of reduced-size antenna. The validity of the program to model simple well-known antennas, such as dipoles and monopoles, is first shown. More complex geometries such as folded dipoles, and meander dipole antennas are also analysed using the program. The final design geometry of a meander folded dipole is characterized with MININEC, yielding results that serve as the basis for the practical construction of the antenna. Finally, the laboratory work with a prototype antenna is described, and practical results are presented.
32
Sener, Goker. "Analysis And Design Of Microstrip Patch Antennas With Arbitrary Slot Shapes." Phd thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613161/index.pdf.
Full textAbstract:
A new method is proposed that provides simple and effcient design and analysis algorithm for microstrip antennas with arbitrary patch shapes. The proposed procedure uses the mutiport network model (MNM) where the antenna is considered as a cavity bounded by perfect electric conductors on the top and the bottom surfaces and perfect magnetic conductor on the side surfaces. Ports are defined along the periphery of the patch, and the impedance
matrix representing the voltage induced at one port due to a current source at another port, is obtained through the use of the 2-D Green&rsquos function corresponding to the cavity. For the MNM analysis of patches with irregular shapes such as slotted structures, the segmentation/desegmentation methods are utilized since the Green&rsquo
s function expressions are available only for regularly shaped cavities. To speed up the analysis and to develop a design procedure, vector Pade approximation is used in order to approximate the antenna impedance matrix as a rational function of two polynomials. When the approximation is performed with respect to frequency, the roots of the polynomial at the denominator provides the resonant frequencies of the antenna. The design algorithm is applicable when the approximation variable is changed to one of the dimensions of the patch that need to be optimized. Because for this case, the roots of the denominator polynomial correspond to optimum dimensions of the antenna where it resonates.
33
Latef, Tarik Abdul. "Design and analysis of a helical antenna printed on a layered dielectric hemisphere." Thesis, University of Sheffield, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.575554.
Full textAbstract:
The development of a wide range and variety of mobile satellite communications and navigation systems such as GPS (Global Positioning System), INMARSAT and MSAT posing new challenges for the design of the antenna with circular polarization (GP) radiation due to their insensitivity to the Faraday effect or rotation. The Faraday rotation is a magneto-optical phenomenon that is an interaction between light and a magnetic field in a medium that causes a rotation of the plane of polarization. In this thesis, a conformal hemispherical helical antennas radiating in a homogeneous medium or printed on a layered dielectric hemisphere to achieve a wideband and wide beam circular polarization radiation with a high gain of -11dBi are rigorously analyzed and measured. A truncated hemispherical helical antenna with adjusted number of turns and hemisphere's radius is proposed to provide optimum 3dB AR bandwidth, 3dB AR beam-width and gain. Truncated helical antennas printed on single and layered dielectric hemispheres have been studied theoretically using the Dyadic Green's functions. Two different approaches are used to enhance the 3dB AR beam-width and bandwidth; the first is based on using a two-layer hemisphere in order to increase the 3dB AR beam-width. The second approach introduces a conformal parasitic wire in the original structure to increase the 3dB AR bandwidth. Due to poor impedance matching at the required GP frequency range, an integrated matching section has been incorporated in the configuration to improve the overlap between the Sll and AR bandwidths. Finally, to increase the gain, 3 element arrays of hemispherical helical antennas that are printed on two-layer hemispheres have been designed. The results obtained from 11 simulations have been verified with the experimental work. Theoretical and experimental results confirm that the proposed techniques to develop a low profile wideband and wide beam circularly polarized antenna are successful where 3dB AR bandwidth of -11 %, 3dB AR beam-width of 1360 and a gain of 11.35 dBi at the lowest AR frequency have been achieved and offer promising results for applications related to mobile communication systems.
34
Vogler, Terry Richard. "Analysis of the Radiation Mechanisms in and Design of Tightly-Coupled Antenna Arrays." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/29282.
Full textAbstract:
The objective of this research is to design well-tuned, wideband elements for thin planar or cylindrically conformal arrays of balanced elements fed over ground. These arrays have closely spaced elements to achieve wide bandwidths through mutual coupling. This dissertation develops two wideband designs in infinite, semi-infinite, and finite array configurations. The infinite array is best for element tuning. This research advances a concept of a distributed, parallel capacitance between elements and across feeds that must be mutually altered for tuning.
Semi-infinite techniques limit the problem space and determine the proper resistive loads to control the low-frequency array-guided surface wave (AGSW). The tight physical placement also forms a periodic structure that, along with the array boundary, launches a wave across the array surface. Options to suppress this surface wave are resistive loading and cylindrical conformations. AGSW control is necessary to achieve a maximum bandwidth, but lower radiation or aperture efficiency results. Conformation is shown to be an ineffective method for AGSW control alone.
The Wrapped Bowtie design emerges as a novel design offering nearly a 10:1 bandwidth as a finite array over ground. Some bandwidth comes from the losses in radiation efficiency, which is necessary to control the AGSW; however, its simulated VSWR < 3 bandwidth in an infinite array is 7.24:1 with full efficiency. Less than perfect efficiency is required to mitigate surface wave effects, unless bandwidth is to be compromised. That loss may be as radiation or aperture efficiency, but it is unavoidable if the infinite array bandwidth is to be maintained in finite array designs.
Lastly, this research articulates a development path for tightly-coupled arrays that extends in stages from infinite to semi-infinite, and thence finite layouts. Distinctions are explained and defended for the design focus at each stage. Element design, tuning, and initial feed design occur at the infinite array stage; AGSW suppression occurs at the semi-infinite stage; and design confirmation occurs only with the finite array.Ph. D.
35
Hanif, Muhammad Fainan. "Aspects of Design and Analysis of Cognitive Radios and Networks." Thesis, University of Canterbury. Department of Electrical and Computer Engineering, 2010. http://hdl.handle.net/10092/5072.
Full textAbstract:
Recent survey campaigns have shown a tremendous under utilization of the bandwidth allocated to various wireless services. Motivated by this and the ever increasing demand for wireless applications, the concept of cognitive radio (CR) systems has rendered hope to end the so called spectrum scarcity. This thesis presents various different facets related to the design and analysis of CR systems in a unified way. We begin the thesis by presenting an information theoretic study of cognitive systems working in the so called low interference regime of the overlay mode. We show that as long as the coverage area of a CR is less than that of a primary user (PU) device, the probability of the cognitive terminal inflicting small interference at
the PU is overwhelmingly high. We have also analyzed the effect of a key parameter governing the amount of power allocated to relaying the PU message in the overlay mode of operation in realistic environments by presenting a simple and accurate approximation. Then, we explore the possibilities of statistical modeling of the cumulative
interference due to multiple interfering CRs. We show that although it is possible to obtain a closed form expression for such an interference due a single CR, the problem is particularly difficult when it comes to the total CR interference in lognormally faded environments. In particular, we have demonstrated that fitting a
two or three parameter lognormal is not a feasible option for all scenarios. We also explore the second-order characteristics of the cumulative interference by evaluating
its level crossing rate (LCR) and average exceedance duration (AED) in Rayleigh and Rician channel conditions. We show that the LCRs in both these cases can be evaluated by modeling the interference process with gamma and noncentral χ2 processes, respectively. By exploiting radio environment map (REM) information, we have presented two CR scheduling schemes and compared their performance with the naive primary exclusion zone (PEZ) technique. The results demonstrate the significance of using an intelligent allocation method to reap the benefits of the tremendous information available to exploit in the REM based methods. At this juncture, we divert our attention to multiple-input multiple-output (MIMO) CR systems operating in the underlay mode. Using an antenna selection philosophy, we solve a convex optimization problem accomplishing the task and show via analysis and simulations that antenna selection can be a viable option for CRs operating in relatively sparse PU environments. Finally, we study the impact of imperfect
channel state information (CSI) on the downlink of an underlay multiple antenna CR network designed to achieve signal-to-interference-plus-noise ratio (SINR) fairness
among the CR terminals. By employing a newly developed convex iteration technique, we solve the relevant optimization problem exactly without performing any relaxation on the variables involved.
36
Cracraft, Michael Andrew. "Mobile array designs with ANSERLIN antennas and efficient, wide-band PEEC models for interconnect and power distribution network analysis." Diss., Rolla, Mo. : University of Missouri-Rolla, 2007. http://scholarsmine.umr.edu/thesis/pdf/mcthesis20070623_09007dcc80374999.pdf.
Full textAbstract:
Thesis (Ph. D.)--University of Missouri--Rolla, 2007.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed November 16, 2007) Includes bibliographical references (p. 134-136).
37
Thews, Jonathan Tyler. "Design and Analysis of L-Band Reconfigurable Liquid-Metal Alloy Antennas." Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/78007.
Full textAbstract:
Efficient reconfigurable antennas are highly sought after in all communication applications for the ability to reduce space cost while maintaining the ability to control the frequency, gain, and polarization. The ability to control these parameters allows a single antenna to maximize its performance in a wide range of scenarios to satisfy changing operating requirements. This thesis will describe reconfigurable antennas using liquid-metal alloys that give the system this ability by injecting or retracting the liquid metal from various channels. After simulations were performed in an electromagnetic simulation software, proof-of-concept models were built, tested, and compared to the simulations to verify the results.Master of Science
38
Pelham, Timothy George. "Analysis of conformal antenna array design using beamforming methods and on-platform aperture modelling." Thesis, University of Bristol, 2018. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.738323.
Full text
39
Moussounda, Renaud. "Analysis and Design of Coupled-Oscillator Arrays for Microwave Systems." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1388354578.
Full text
40
Liu, Ran, and Hao Liu. "Maximum Capacity Antenna Design for an Indoor MIMO UWB Communication System." Thesis, Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-4476.
Full textAbstract:
Ultra-wideband (UWB) offers a high data rate transmission, however it only can be used in short distance communication due to its low power restricted by regulations, therefore it is applicable for an indoor scenario. Within an enclosed (indoor) scenario, there exist many possible multipaths of electromagnetic waves which lead to an effect known as fading [Big07]. Since SISO systems suffer severely from it, in contrast, multiple-output-multiple-input (MIMO) systems take advantage of this multipath/diversity effect. Typical MIMO system utilizes antenna arrays to generate subchannels, but it has no guarantee of orthogonal channels or maximum capacity. Using a new antenna synthesis algorithm, optimal subchannels can be computed by decomposing the MIMO channel into parallel SISO subchannels through the employment of sampling antennas. Thereafter optimal real word antennas can be designed according to the synthesized antenna radiation pattern which result in the reduced hardware. The goal of this thesis will be expressed as follows: Firstly, a good strategy planning to reduce computing effort should be realized since all the design parameters to be analyzed are frequency dependent. Furthermore, a systematic framework of the synthesis must be designed for the UWB band. Lastly, the corresponding real world antenna should be designed and verified. In this thesis, a systematic synthesis framework has be developed and analyzed for the UWB spectrum. The channel matrix acquisition, the design of the ‘sampling antennas’ along with the algorithm to decompose the MIMO channel into parallel independent SISO subchannels are discussed in detail. Two realizations of the real world antennas as well as all the challenges in the design process are also presented. As consequences, an antenna system with optimal radiation pattern has been synthesized. This antenna system radiates orthogonal channels with sufficient power and has fixed beamforming (direction optimized according to the scenario and with averaging over various positions along with rotations) at the transmitter and receiver. The maximum capacity takes into account the scenario, frequency band, physical available space for the antenna array and polarization (added degree of freedom). This work also organizes the antenna synthesis algorithm for UWB in a systematic framework, meeting the objectives of the project.In this thesis, a UWB antenna synthesis based on the averaging strategies for the predefined indoor communication scenarios has been proposed, which contains both the indoor communication theoretical analysis and real world realization. The algorithm can be applied in an arbitrary indoor scenario over ultra wideband frequency. All synthesized results demonstrated that the designed sampling antenna configuration is able to provide optimized solutions. The synthesis method is based on computing optimal antenna configurations for a MIMO ultrawideband system. In order to maximize the throughput, there exists a sampling volume for both transmit and receive antennas. As such, the face-centered and body-centered cubic antenna arrays are utilized. Given that the system operates in the UWB band with a cognitive feature, the type of antenna, orientation, placement and MIMO diversity scheme have been well investigated. The radiation patterns of the antenna array cover the sampling volume and the bandwidth cover the UWB band. The goal of this thesis work concentrates on the analysis of an indoor communication to find an optimum solution on the antenna configuration and placement. The final objective was to design and realize an optimal MIMO-UWB antenna system.
Add: Waldhornstrasse 19, Karlsruhe, 76131, Germany Tel: +49 176 34467663
41
"Design and analysis of proximity coupling feeds for multi-layer patch antennas: T-square feed and its two variations." 2005. http://library.cuhk.edu.hk/record=b5892402.
Full textAbstract:
Lee Wai Ki.Thesis submitted in: May 2004.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2005.
Includes bibliographical references (leaves 62-66).
Abstracts in English and Chinese.
Chapter Chapter 1: --- Introduction --- p.8
Chapter 1.1 --- Motivation --- p.8
Chapter 1.2 --- Organization of the thesis --- p.10
Chapter Chapter 2: --- Background Technology --- p.12
Chapter 2.1 --- Introduction: FUZZY EM CAD formula for impedance of the edge of the patch antenna --- p.12
Chapter 2.2 --- Fringe field extension of the patch: --- p.12
Chapter 2.2.1 --- Applying the root of area capacitance formula --- p.12
Chapter 2.2.2 --- Defining microstrip parallel plate capacitor with infinite substrate --- p.13
Chapter 2.2.3 --- The parallel plate capacitor formula --- p.14
Chapter 2.2.4 --- DC fringe field leading to the patch extension --- p.15
Chapter 2.3 --- Cavity model of the patch --- p.16
Chapter 2.3.1 --- Cavity model analysis on its internal field --- p.16
Chapter 2.3.2 --- Input impedance derived from cavity model --- p.19
Chapter 2.3.3 --- Quality factor of patch antenna --- p.19
Chapter 2.4 --- Fringe extension applied to cavity model in RF --- p.23
Chapter Chapter 3: --- Simple one Port wide band multi-layer patch Antenna --- p.24
Chapter 3.1 --- Introduction --- p.24
Chapter 3.2 --- Antenna design --- p.25
Chapter 3.3 --- Measured results --- p.26
Chapter 3.4 --- Antenna Analysis --- p.29
Chapter 3.5 --- Conclusion --- p.30
Chapter Chapter 4: --- Design synthesis of patch antennas of the T-square Probe --- p.31
Chapter 4.1 --- Introduction --- p.31
Chapter 4.2 --- The physics interpretation --- p.32
Chapter 4.3 --- The Smith chart movement by the T-square feed on the patch --- p.33
Chapter 4.4 --- Conclusion --- p.35
Chapter Chapter 5: --- Design synthesis of the wideband tuning-fork-shaped feeding for patch antenna --- p.36
Chapter 5.1 --- Introduction --- p.36
Chapter 5.2 --- Antenna design --- p.36
Chapter 5.3 --- The Smith chart movements of the tuning-fork shaped feeding on the patch --- p.37
Chapter 5.4 --- Conclusion --- p.41
Chapter Chapter 6: --- "Fork on H-slot feed of multilayer microstrip antenna for wideband, high isolation and low cross polarization" --- p.42
Chapter 6.1 --- Introduction --- p.42
Chapter 6.2 --- Antenna analysis - Isolation improvement considerations --- p.44
Chapter 6.3 --- Antenna design and measured results --- p.46
Chapter 6.3.1 --- The simulated return loss and current distribution s in various structure of the two port. --- p.47
Chapter 6.3.2. --- The hardware and the comparison of results --- p.50
Chapter 6.3.3. --- The simulated properties of the radiation patterns and cross-polarizations --- p.52
Chapter 6.3.4. --- The comparison of radiation patterns between simulation and hardware --- p.56
Chapter 6.4 --- Further improvements --- p.58
Chapter 6.5 --- Conclusion --- p.59
Chapter Chapter 7: --- Conclusions --- p.60
Reference --- p.62
List of Publication --- p.66
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Lu, Zih-Hao, and 盧子豪. "Design and Analysis of Compact Antennas and Diversity Antenna for Wireless Communication." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/41521658313880477229.
Full textAbstract:
碩士國立臺北科技大學
電腦通訊與控制研究所
92
In this thesis, we will discuss two topics about antennas. First, the slow wave effects will be used to design the compact antenna. The elementary structure of the compact antenna is that shorting and feeding positions are located respectively on both sides of the designed antenna. The slow wave effect will be introduced by etching applicable geometric figures on radiator of the antenna and the slow wave effect can be changed by adjusting the etching position. The measurement results show that the significant slow wave effect is introduced, if the etching geometric figure on the radiator of the antenna is placed at the position where has large the current density. Then more obvious slow wave effect introduces the lower relative resonant frequency. So the antenna size can be reduced significantly by the introduction of slow wave property. Also, modifying the width and height of antenna is alternative way to reduce the size of antenna. The other topic about antenna presented in this thesis will study two configurations of switched-beam diversity antennas for wireless communication. In the first configuration, two patch antennas separating form a two elements antenna array. The feeding phases of each antenna element can be changed from in-phase to out-of phase by switching the appropriate pin-diodes on-off status. Then the array factor of the patch antenna array can be changed from end-fire direction to broadside direction. In the second configuration, two thin conductors are put on both sides of one dipole antenna and the both distances between each thin conductor and the dipole antenna are set as . For each thin conductor, there is a break point on the middle, then mount a pin-diode on the break point. Because the length of two thin conductors are longer than the length of the dipole antenna, two thin conductors will be equivalent as inductive reflector or capacitive reflector by switching the pin-diode to on or off status respectively. Hence, the main beams of this configuration can be switched and almost have 180o difference. For the above mentioned two configurations, the experiments show the switched-beams have low correlation coefficients 0.0318 and 0.0837 respectively. Only one feeding port is needed to configure the switched-beam antennas and the small distance between the array elements is needed to provide enough low correlation for the proposed configurations. These above mentioned antenna configurations are suitable to design the practical wireless communication systems. This is major contributions in this thesis.
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Huang, Yun-Fang, and 黃韻芳. "Multi Function Active Antenna System-Design and Analysis of Antenna Array." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/52317016904699299767.
Full textAbstract:
碩士元智大學
通訊工程學系
98
This thesis investigates the Multi Function Active Antenna System with the Design and Analysis of the Antenna Array by using the electromagnetic simulation and the real model implement. The antenna design for this Active Antenna System will “improve the 2.4GHz WLAN throughput rate and transmission distance” while it can automatically choices the antenna radiation pattern which will adapt the environment scenario requirement by the portfolio of the algorithm in the system. The radiation terminal of the system is so called a symmetrical array antenna, and by using the traditionally method of the multi-angle radiation for the array antenna is not easy to implement due to the complex impedance system control. This thesis offer an significant view point that using the common grounding system and floating coupling approach for the antenna radiation angle switching without the impedance modification for the radio frequency input from the feeding system. The structure of the antenna array design has one main radiation mono-pole type antenna with 6 switching quarter wavelength mechanisms around the main radiation mono-pole type antenna with quarter wavelength distance. By the switching control for the grounding and floating of the 6 mechanism the complete antenna array system offers 12 different radiation patterns which cover the 0 degree to 360 degree. The benefit of the controllable high gain antenna radiation system is not only to provide the good signal strength for the link system but can reduce the network loading depend on the multi-path environment with more than one base-station and more than one subscriber. The application can be used for not only the terrestrial wireless infrastructure but hand-held equipment after minimize the antenna dimension for the suitable application to have better wireless communication performance in the different scenario.
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Lan, CHeng-Wei. "Analysis and Design of Multifilar Helical Antenna." 2004. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-1407200417184300.
Full text
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柯承志. "Design and analysis of broadband active antenna." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/09576032413213564502.
Full textAbstract:
碩士大葉大學
電機工程研究所
90
Due to the trend of faster speed and higher frequency demands on electronic and telecommunication systems, there is an increasing problem for the electromagnetic compatibility (EMC) and also the trouble on the measuring electromagnetic interference signals. The measurement problem arose from the nature of cable loss in the high frequency ranges (greater than GHz). Because the strength of received signal attenuates rapidly along the cable between the receiving antenna and receiver, it is difficult and impractical to detect and analyze the high frequency signal (even install an pre-amplifier in front of receiver). The thesis investigates the design of broadband active antenna with moderate gain over the frequency range 1GHz — 6 GHz, and thus to solve the measurement problem for high frequency EMI and RF Tests. The works of the thesis is first to implement the S-parameters of amplifier module from manufacturer (Mini-Circuit), then use the microwave amplifier design principles and utilize the microwave circuit design software (Microwave Office 2000) to simulate and analyze the low noise amplifier (LNA), finally use the lump elements and microstrip lines to match the impedances, and therefore fine-tune the LNA performance on the printed circuit board (FR4). After the LNA circuit is finished, it is mounted on the dedicated horn antenna to measure the S-parameters and antenna patterns of the integrated active antenna system. The system measurement is conducted in the CSIST and proved to be effective for the high frequency measurements.
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Wan, Yu Juei, and 萬又瑞. "Hexagonal Fractal Patch Antenna Design and Analysis." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/76911131122368616678.
Full textAbstract:
碩士清雲科技大學
電機工程研究所
94
Recently, wireless communication application has been well-developed. In which the antenna is the key component of the transmission. The antenna has various structures. There has been a rapidly development and growing interest in fractal antennas design and application. Basically, it exhibits a frequency independent antenna after a self-similar design. In practice, specific fractal configuration with great benefit in product multiband characteristic has been developed. Its properties included which miniaturization in size, wideband and multiband, low cost and high gain. It is a valuable work that for application. For fractal antennas, However, the hexagonal are the basic structures the line, the triangle, the square, the circular and hexagonal, structure utilization are quite few. Therefore, this thesis uses the self-similar the characteristic to design three kind of hexagonal fractal antenna. There are corner outward interation, side inward interation and corner inward interation. Mean which, changing ground plane angle, thickness and dielectric substrate separately to discuss frequency responses and radiation patterns. Finally, for corner inward interation, as the ground plane with on right, thickness is 1.6mm. and dielectric substrate is 4.4, the performance frequency in 3.62GHz / bandwidth（14%）, gain（4.59dBi）, the frequency among 5.02 to 7.58GHz / bandwidth（49.23%）, is obtain for application.
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Su, Chia-Wen, and 蘇家雯. "Design and Analysis of RFID System Antenna." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/27368349178720546972.
Full textAbstract:
碩士國立臺灣海洋大學
通訊與導航工程系
95
Abstract Because of the department communication system, it provides people more convince in regular live such as saving manpower and time. In the future communication, RFID used at management of stock this kind of new and developing market can deal with people affair everyday besides voice ,image communication, wire and wireless communication. Due to its wide application, we research and study antenna more from application frequency, the outline of product , the transmission distance and property and design for matching chip. Take the application level of RFID of view , the common characteristic of stocking, billing, identification characteristic is shorten-used , and non-recycle. Hence ,I won’t use metal if we want to Mass product, saving cost , be easily surface cohered. I consider to use polyvinyl chloride (PVC) and PET with dielectric constant about three for designing RFID antenna .I verify my point to use FR-4 PCB in RFID research for experiment convince and measure its bandwidth , radiation pattern, VSWR and so on. In the thesis of researching and design RFID antenna, I take dipole antenna structure for Reader system and Folded Antenna for Tag system because of wide beam, bandwidth and unbalance input. Base on the theory of shorten dipole and the length of effective antenna ,I design Dipole Reader Antenna with 50 ohm system input and covering the frequency of 866MHz、915MHz and 953MHz.Its impedance bandwidth is about 100MHz (S11<-10dBm) . I design 1/4 wavelength impedance transfer to match 50 ohm between Antenna and Reader chip. I change the area of ending loading to fine tune the imaginary impedance and make it slowly change. I design Tag Antenna to take Folded Antenna with the effective antenna length structure. Folded Antenna control imaginary impedance and the effective antenna length deal with real impedance.
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Hung, Ming-I., and 洪明誼. "Advanced Annular Beam Antenna Design and Analysis." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/94701796990905909799.
Full textAbstract:
碩士國立中正大學
電機工程研究所
83
This resarch is to develop an annular beam antenna for the satellite communication and remote-sensing systems used. The far-field pattern of the annular beam antenna has the advantages of uniform earth coverage and better characteristics than conventional beam pattern. There are two types of annular beam antennas investigated in the thesis, it treated as a planar phase array antenna and the regular shaped parabolic reflector antenna. The far-field solutions from aperture distribution are derived from Maxwell's equation, then applied it to analyze the planar phase array antenna. The cylindrical annular beam and spherical annular beam are two types of planar phase array antenna which meet the different shape of annular beams. On the other hand, the regular shaped reflector antenna was submitted for its simple symmetrical configure and using single feed source. The same results were derived from two points of view, they are the circular cone surface aperture distribution and the circular plane surface aperture distribution. At last, the far-field patterns of contour plots and E-plane cuts are simulated by the use of the developed computer programs for various design parameters. It can achieve various shapes of annular beam patterns by modified the parameters.
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Lan, CHeng-Wei, and 藍政惟. "Analysis and Design of Multifilar Helical Antenna." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/74798119575308327468.
Full textAbstract:
碩士國立臺灣大學
電信工程學研究所
92
Tape helix and sheath helix models are used to develop design rules for bifilar helical antenna( BHA). Operational range of parameters are also organized to facilitate the design. Design examples for dual-band GPS and satellite persional communication network are demonstrated. Shaped conical radiation patterns with 0 < G,max < 90 and 3 dB < gain < 20 dB can be implemented by proper choice of , C , and N. The measured results show that the bandwidth with 10 dB return loss is from 1 to 2 GHz. This BHA has good quality of circular polarization when frequency is below 1.6 GHz.
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Chen, Teng-Kai. "Analysis and Design of a Multifunctional Spiral Antenna." Thesis, 2012. http://hdl.handle.net/1969.1/ETD-TAMU-2012-08-11581.
Full textAbstract:
The Archimedean spiral antenna is well-known for its broadband characteristics with circular polarization and has been investigated for several decades. Since their development in the late 1950's, establishing an analytical expression for the characteristics of spiral antenna has remained somewhat elusive. This has been studied qualitatively and evaluated using numerical and experimental techniques with some success, but many of these methods are not convenient in the design process since they do not impart any physical insight into the effect each design parameter has on the overall operation of the spiral antenna. This work examines the operation of spiral antennas and obtains a closed-form analytical solution by conformal mapping and transmission line model with high precision in a wide frequency band.
Based on the analysis of spiral antenna, we propose two novel design processes for the stripline-fed Archimedean spiral antenna. This includes a stripline feed network integrated into one of the spiral arms and a broadband tapered impedance transformer that is conformal to the spiral topology for impedance matching the nominally-high input impedance of the spiral. A Dyson-style balun located at the center facilitates the transition between guided stripline and radiating spiral modes. Measured and simulated results for a probe-fed design operating from 2 GHz to over 20 GHz are in excellent agreements to illustrate the synthesis and performance of a demonstration antenna. The research in this work also provides the possibility to achieve conformal integration and planar structural multi-functionality for an Unmanned Air Vehicle (UAV) with band coverage across HF, UHF, and VHF. The proposed conformal mapping analysis can also be applied on periodic coplanar waveguides for integrated circuit applications.