Дисертації з теми "Reconfigurable and scanning antenna arrays"
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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.
Повний текст джерелаRodenbeck, Christopher Timothy. "Novel technologies and techniques for low-cost phased arrays and scanning antennas." Diss., Texas A&M University, 2004. http://hdl.handle.net/1969.1/1053.
Повний текст джерелаButtazzoni, Giulia. "Study and development of power synthesis techniques of arbitrary reconfigurable antenna arrays for satellite applications." Doctoral thesis, Università degli studi di Trieste, 2013. http://hdl.handle.net/10077/8536.
Повний текст джерелаThe material presented in this thesis is the result of the Ph.D. activity carried on between January 2009 and December 2012 at the Ph.D. school in Information Engineering of the University of Trieste. After a brief introduction on the involved topics, the final objective of this thesis is that of presenting the original results, consisting in the development of power pattern synthesis algorithms for arbitrary antenna arrays including, in particular, arrays for satellite applications. Since the earlier satellite missions of last century, satellite communication systems have received growing attention due to the opportunities they offer and their greater flexibility with respect to alternative solutions adopting other media, such as, for example, fiber optic cables. The enormous spread of satellites, for both military and civilian applications, has been achieved thanks to the experienced technological progress, which has allowed an increase of satellite capacities. The need of constantly increasing the capacity of commercial communications satellites resulted in the continuing evolution of the antenna systems onboard the satellites. The business environment has driven the architecture of satellites' systems towards more efficiency and cost consciousness while at the same time, providing flexible access to a growing diversity of services and customers. Antennas that provide a multiplicity of frequency reuse coverage beams through either spatial or polarization isolation have been developed, resulting in the evolution of satellite antennas from a simple omnidirectional dipole to multiple-beam, dual-polarized configurations with frequency reuse between the beams for increased capacity. These requirements translate into high-gain, high-efficiency antennas with low side-lobe levels and excellent polarization purity. Moreover, since new requirements are often determined after the satellite is operational, antennas adjustable to produce a wide variety of radiation patterns have become popular. These are the so-called multiple-beam antennas, which can adjust their radiation coverage areas according to new demands. Multiple-beam antennas are currently being used for direct-broadcast satellites, personal communication satellites, military communication satellites, and high-speed Internet applications. High-gain multiple-beam antenna systems usually take one of three generic forms: lens, reflector or direct radiating array. Thus, arrays of antennas can be used in multiple-beam systems either to feed other types of antennas, or directly as radiating structures. The material of this thesis is mainly related to the synthesis algorithms for antenna arrays. In particular, many analytical and numerical techniques for the power pattern synthesis of antenna arrays have been carefully studied and analyzed. Some of them are suitable only for linear or rectangular arrays, the others for arrays of more complicated geometries. Furthermore, it is extremely important, for power synthesis techniques in satellite applications, to be able to consider additional constraints. These typically are the phase-only reconfigurability of the radiated beams, the control of the cross-polar patterns, which allows the polarization re-use and/or the control of the cross-polar interference, the dynamic range ratio reduction which comports simpler feeding networks and lower mutual coupling between array elements, and the near-field reduction, which allows to take into account the antennas operating environment. A numerical iterative algorithm has been developed during the Ph.D. school in Information Engineering, suitable for arrays of arbitrary geometry, thus including sparse and conformal arrays, which are often used in satellite applications. The algorithm allows to solve the power pattern synthesis problem, which is an inherently non linear problem. The solution is achieved using the alternating projections algorithm, which is a numerical iterative technique for finding a point of the intersection between two sets. It will be seen that the projections method has previously already been applied to problems of image processing and also in the antenna pattern synthesis. However, the results and the computational burden are strongly related to the projection operators, which in turn, strictly depend on the definition of the adopted distance, thus on the definition of the sets adopted in the formulation of the problem. Thus, the main originality of the developed algorithms consists in an extremely advantageous definition of the sets involved in the solving scheme, which, along with the adopted distance, allow an easy evaluation of the projection operators and thus a simple solving procedure. The thesis is organized as follows. Chapter 1 introduces the satellite antennas, analyzing some solutions adopted in the past. Particular attention is devoted to multiple-beam antennas (MBAs) and in particular to arrays of antennas, which can constitute the feeding system of reflector MBAs, or which can be used as direct radiating antennas themselves. Chapter 2 presents analytical and numerical methods of power pattern synthesis for antenna arrays proposed in the literature. First, the classical analytical methods, suitable for linear arrays of equally spaced elements are presented. Then, numerical iterative methods are analyzed. Attention is devoted to both deterministic and stochastic algorithms. A section is dedicated to the near-field constraint, due to its importance in practical real applications. In fact, taking into account the effect of the antenna operating environment is of fundamental importance: obstacles or mounting platforms, as well as other electronic devices located in proximity of the antenna, may strongly degrade the radiated far-field pattern. Then, Chapter 3 presents the developed algorithm. Precisely, the evolution is described from a synthesis algorithm suitable for arbitrary phase-only reconfigurable arrays to a powerful algorithm for phase-only antenna arrays, including several additional constraints, such as the dynamic range ratio reduction, the cross-polar pattern synthesis and the near-field reduction. Moreover, in its final form, the algorithm also allows to minimize the power radiated in the side-lobe regions of both the co- and cross-polar patterns and the electric energy stored in the near-field region of interest. Numerical results validating the effectiveness of the proposed algorithm are presented in Chapter 4 and the conclusions are summarized in Chapter 5. Finally, the appendix mathematically describes the classical alternating projections method and the genetic algorithms, which have been used as global optimization algorithms for comparison purposes.
Il materiale presentato in questa tesi è il risultato dell'attività svolta durante il dottorato tra gennaio 2009 e dicembre 2012 presso la scuola di dottorato in ingegneria dell'informazione dell'università di Trieste. Dopo una breve introduzione sugli argomenti trattati, l'obiettivo ultimo della tesi è quello di presentare i risultati originali che consistono nello sviluppo di algoritmi di sintesi di potenza per antenne a schiera di geometria arbitraria tra le quali, in particolare, schiere per applicazioni satellitari. Fin dalle prime missioni spaziali del secolo scorso, le comunicazioni satellitari hanno ricevuto attenzione crescente grazie alle opportunità che offrono e alla loro maggior flessibilità rispetto a soluzioni alternative che utilizzano altri sistemi, come ad esempio i cavi in fibra ottica. Grazie agli sviluppi tecnologici avvenuti, che hanno reso possibile un aumento delle capacità dei satelliti, si è sperimentata una vasta diffusione di satelliti per applicazioni militari e civili. La necessità di aumentare costantemente la capacità dei satelliti per comunicazioni commerciali ha comportato una continua evoluzione delle antenne da satellite. L'ambiente commerciale ha spinto l'architettura dei sistemi satellitari verso una miglior consapevolezza di efficienza e costi consentendo, allo stesso tempo, un accesso flessibile a un sempre maggior numero di servizi e di utenti. Sono state sviluppate antenne che consentono una molteplicità di fasci con riutilizzo della frequenza grazie ad isolamento spaziale o di polarizzazione. Questo ha generato un'evoluzione delle antenne da satellite dal semplice dipolo omnidirezionale ad antenne a fascio multiplo, con alto guadagno, alta efficienza, bassi lobi laterali ed elevata purezza di polarizzazione. Inoltre, poichè nuove necessità spesso emergono una volta che il satellite è già operativo, si sono diffuse antenne da satellite configurabili in modo da poter produrre diversi diagrammi di radiazione. Queste sono le così dette antenne riconfigurabili, che possono modificare le regioni coperte in base a nuove necessità. Antenne a fascio multiplo vengono usate correntemente in trasmissioni dirette via satellite, satelliti per comunicazioni personali, satelliti per comunicazioni militari e applicazioni Internet ad alta velocità. I sistemi di antenne a fascio multiplo ad elevato guadagno generalmente sono di uno dei seguenti tre tipi: lenti, riflettori o antenne a schiera. Dunque le antenne a schiera si possono trovare nelle applicazioni satellitari sia come strutture per alimentare altri tipi di antenne, sia come strutture radianti direttamente. Il materiale presentato in questa tesi è principalmente legato agli algoritmi di sintesi per antenne a schiera. In particolare, sono stati attentamente studiati e analizzati diversi metodi, analitici e numerici, per la sintesi di potenza di antenne a schiera. Alcuni di questi sono applicabili solo a schiere lineari o rettangolari, altri a schiere di geometria più complicata. Inoltre, è estremamente importante per gli algoritmi di sintesi di potenza di schiere per applicazioni satellitari essere in grado di considerare vincoli addizionali. Questi tipicamente sono la riconfigurabilità del fascio tramite controllo di sola fase, il controllo del diagramma cross-polare, che permette di ottenere il riutilizzo di polarizzazione e/o di controllare l'interferenza cross-polare, la riduzione della dinamica, che permette l'utilizzo di reti di alimentazione più semplici e un abbassamento del mutuo accoppiamento tra gli elementi della schiera, e la riduzione del campo vicino, che permette di tener conto dell'ambiente in cui opera l'antenna. Durante il dottorato è stato sviluppato un algoritmo numerico iterativo per schiere di geometria arbitraria, perciò comprese le schiere sparse e conformi, spesso impiegate in applicazioni satellitari. L'algoritmo permette di risolvere il problema (intrinsicamente non lineare) di sintesi di potenza. La soluzione è ottenuta mediante l'impiego del metodo delle proiezioni succesive, un metodo numerico iterativo per trovare un punto nell'intersezione tra due insiemi. Tale metodo è stato usato in passato in problemi di elaborazione delle immagini e anche in problemi di sintesi di antenne a schiera. Ciononostante, i risultati e il carico computazionale sono direttamente legati ai proiettori, che a loro volta sono strettamente dipendenti dalla definizione della distanza adottata, dunque degli insiemi coinvolti nel problema. Perciò, la principale originalità degli algoritmi sviluppati consiste in una definizione degli insiemi estremamente vantaggiosa in quanto, assieme alla scelta della distanza, permette di valutare facilmente i proiettori e perciò permette di ottenere una procedura di soluzione semplice. La tesi è organizzata come segue. Il primo capitolo introduce le antenne da satellite analizzando alcune soluzioni utilizzate in passato. Particolare attenzione è rivolta alle antenne a fascio multiplo e in particolare alle antenne a schiera, che possono costituire il sitema di alimentazione di antenne a riflettore multifascio o che possono esse stesse essere usate come elementi radianti. Il secondo capitolo presenta metodi analitici e numerici per la sintesi di potenza per antenne a schiera proposti in letteratura. Dapprima vengono presentati i metodi analitici classici, validi per schiere lineari di elementi equispaziati. Successivamente vengono analizzati i metodi numerici iterativi, sia stocastici, sia deterministici. Una sezione a parte è dedicata al vincolo sul campo vicino, vista la grande importanza che riveste nelle applicazioni pratiche. Infatti è di fondamentale importanza tener conto degli effetti dell'ambiente in cui l'antenna opera in quanto ostacoli o strutture di montaggio, così come altri apparati elettronici in prossimità dell'antenna, possono causare forti interferenze e degradare notevolmente il diagramma di campo lontano. Il capitolo 3 presenta gli algoritmi sviluppati. Precisamente, viene delineata l'evoluzione da un algoritmo di sintesi di potenza per schiere riconfigurabili di geometria arbitraria con controllo si sola fase, a un potente algoritmo di sintesi di sola fase con diversi vincoli addizionali, quali la riduzione della dinamica, la sintesi del fascio cross-polare e la riduzione del campo vicino. Inoltre, nella sua forma finale, l'algoritmo permette di minimizzare la potenza irradiata nelle regioni di lobi laterali di entrambi i diagrammi, co- e cross- polare, e l'energia immagazzinata nella regione di campo vicino presa in considerazione. I risultati numerici che provano l'efficacia del metodo sono presentati nel capitolo 4 e le conclusioni sono riassunte nel capitolo 5. Infine, l'appendice descrive matematicamente il classico metodo delle proiezioni successive e gli algoritmi genetici, che sono stati scelti come termine di paragone tra gli algoritmi di ottimizzazione globale.
XXIV Ciclo
1983
Nagesh, S. R. "Synthesis of Arbitrary Antenna Arrays." Thesis, Indian Institute of Science, 1995. http://hdl.handle.net/2005/160.
Повний текст джерелаPapantonis, Dimitrios Papantonis. "Tightly-Coupled Arrays with Reconfigurable Bandwidth." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1503046689468305.
Повний текст джерелаYetisir, Ersin. "Novel Implementations of Wideband Tightly Coupled Dipole Arrays for Wide-Angle Scanning." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1449120804.
Повний текст джерелаTowfiq, MD Asaduzzaman. "Application Aware Reconfigurable Antennas and Arrays for 5G and Beyond Wireless Communication Systems." DigitalCommons@USU, 2018. https://digitalcommons.usu.edu/etd/7250.
Повний текст джерелаKhalat, Abdurazag Mohamed. "Multifunctional Reconfigurable Antennas and Arrays Operating at 60 GHz band." DigitalCommons@USU, 2017. https://digitalcommons.usu.edu/etd/5616.
Повний текст джерелаNoordin, Nurul Hazlina. "Adaptive array antenna design for wireless communication systems." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/8950.
Повний текст джерелаGokalp, Nihan. "Beam Steerable Meanderline Antenna Using Varactor Diodes And Reconfigurable Antenna Designs By Mems Switches." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609982/index.pdf.
Повний текст джерелаbeam-steerable meanderline antenna, dual circularly polarized meanderline antenna and dual-frequency slot-dipole array. Traveling wave meanderline antenna arrays are investigated in detail and a beam-steerable traveling wave meanderline antenna array has been introduced for X-band applications. Beam-steering capability of the antenna array has been achieved by loading the antenna elements with varactor diodes. Theoretical analysis and computer simulations of the proposed antenna have been verified with experimental results. Radiation direction of the 8-element meanderline array can be rotated 10°
by changing the varactor diode&rsquo
s bias voltage from 0V up to 20V. Also, a polarization-agile meanderline antenna array has been designed and simulated. Polarization of the circularly polarized meanderline array can be altered between right hand circularly polarized and left hand circularly polarized by using RF MEMS switches. The third type of reconfigurable antenna investigated in this thesis is a dual frequency slot-dipole array operating at X- and Ka-band. Electrical length of the slot dipoles has been tuned by using RF MEMS switches. Antenna prototypes have been manufactured for &lsquo
on&rsquo
and &lsquo
off&rsquo
states of RF MEMS switches and it has been shown that the operating frequency can be changed between 10 GHz and 15.4 GHz.
Jaeck, Vincent. "Développement d’antennes de communication reconfigurables en bande C pour munitions intelligentes." Thesis, Rennes 1, 2016. http://www.theses.fr/2016REN1S104/document.
Повний текст джерелаNowadays wireless communications have become a useful and universal mean to exchange a wide range of information between different systems, some of them being moving, as UAVs among others. In this context we consider here the link between a projectile and a base station. The shape of the structure and the aerodynamic constraints involve the use of patch antennas in the conical front part. This class of antenna is easy to be integrated into the platform as a conformal array, while respecting space constraint. Communications have to be reliable and discrete in disturbed or hostile environment. Antennas array radiation patterns must have some specific characteristics, in particular in the case of flying objects with spin which involves the use of a switched phased array considering its roll position. A fixed-radiation pattern antenna may presents a relevant level or gain toward the interlocutor, but also toward sensitive directions, in which may be located others systems, interfering with the current communication. The solution to switch on and off vertical sub-arrays to steer the beam in the azimuthal plane seem convenient ant fitting the requirements of rotating platform. A conical phased array was studied and two prototypes were manufactured, one at ISL. Sub-arrays are distributed around the conical shape in order to be able to radiate in each direction. Moreover, each sub-array are composed of three radiating elements allowing to steer the main antenna beam in many direction (along the projectile fuze axes). A beam forming network was developed to control the 12 radiating elements conical array. The antenna array and the feeding network were characterized independently in order to optimized the phase of each radiating element. Finally, measurements were done on the whole system in the DGA-MI and ISL anechoic chambers and are in good agreement with simulation results
Oueslati, Aymen. "Nouveau concept simplifié d’antennes reconfigurables utilisant les couplages interéléments : Mise en œuvre d’un réseau hybride." Thesis, Limoges, 2015. http://www.theses.fr/2015LIMO0136/document.
Повний текст джерелаThe work of this thesis aims to investigate a new concept of reconfigurable antenna allowing a good trade-off between performances, complexity and cost. This concept is called ‘hybrid’ because it is based on the capabilities of thinned arrays and parasitic element antennas. It is an alternative to classical antenna arrays and their complexity. The proposed concept has a modular architecture, and a good versatility for reconfigurable beams. The main advantage of this hybrid antenna is the simplicity of its beam formation network (BFN) which requires only a few number of excited elements. The antenna uses parasitic elements to manage the effects of couplings between the electromagnetic access. The problematic of active VSWR is also solved at the antenna level, avoiding the use of additional components in the BFN. This work details the principle of the reconfigurable hybrid antenna concept. The potentialities are evaluated. The elements required to realize a proof of concept are then defined, using a dedicated experimental setup. A prototype is manufactured and the performances have been checked to validate this innovative concept
Gray, Jordan D. "Application of Floating-Gate Transistors in Field Programmable Analog Arrays." Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7540.
Повний текст джерелаFoglia, Manzillo Francesco. "Wideband and flat multibeam antenna solutions for ultrafast communications in millimeter band." Thesis, Rennes 1, 2017. http://www.theses.fr/2017REN1S110/document.
Повний текст джерелаThe ever-growing demand for fast and seamless connectivity shows the need of new wireless standards and technologies. Novel broadband, wide-angle scanning antennas achieving an optimal trade-off among size, gain, efficiency and costs are crucial to the development of emerging applications at millimeter waves, such as fifth-generation (5G) mobile networks and satellite communications. In this thesis, multibeam parallel-fed continuous transverse stub (CTS) array antennas are proposed as possible candidates for future mm-wave communications and are developed to tackle these requirements. The antenna architecture comprises an array of long slots, a corporate feed network based on parallel plate waveguides (PPWs) and an integrated quasi-optical beamformer. First, novel numerical models for the analysis of each subsystem and of the overall antenna, are presented, which enable an efficient and modular design of CTS antennas. These tools are exploited to derive design guidelines and assess the scanning performance. Then, novel design and technological solutions for the integration of CTS antennas in flat, low-profile multilayer modules are discussed. The design and characterization of two prototypes in LTCC technology, for 60-GHz mobile access points are presented: a fixed beam array and a switched-beam antenna with a field of view of ±40°, low SLLs and high beam overlap. Finally, planar linear-to-circular polarization converters are proposed to realize circularly polarized CTS antenna systems. A procedure to achieve an ultra-wideband, low-loss polarization conversion is outlined and a design for Ka-band satellite application is presented
Jones, Aaron M. "Frequency Diverse Array Receiver Architectures." Wright State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=wright1323888275.
Повний текст джерелаAlzein, Hala. "Développements de nouvelles architectures d’antennes reconfigurables pour les applications de télécommunications de 5ème génération." Thesis, Limoges, 2020. http://www.theses.fr/2020LIMO0014.
Повний текст джерелаThe fast development of wireless communication led to an increasing demand for new developments on antennas. These developments were backed by an urgent need for more complex architectures due to the need of reconfigurability in terms of frequency, reliability, radiation pattern and power consumption. In order to cover those needs, this work is based on an original reconfigurable antenna with a simplified feed network developed by XLIM laboratory, to offer an attractive tradeoff in terms of performances, complexity and cost. This new architecture is based on previous works from the laboratory (2012-2015) and a first proof of concept working at 2.45 GHz. The work proposed for this PhD is based on the development of this new architecture to manage the problems of periodic antenna arrays. Two main axes were developed during this work. The first axis consists to demonstrate the interest of this concept to manage the active VSWR of each excited element using loads connected to the parasitic elements, avoiding the need for circulators, while reducing the complexity of feed network. The second part of our work is dedicated to illustrating the potentialities of these antennas to reduce the grating lobes, while defining a constraint on the level of sidelobes. A manufactured prototype is presented in order to experimentally validate the potentialities of these antennas
Santamaria, Luca. "Systèmes d'antennes reconfigurables intégrés dédiés aux réseaux IoT sans fil dynamiques." Thesis, Université Côte d'Azur, 2021. http://www.theses.fr/2021COAZ4103.
Повний текст джерелаBecause of the unique characteristics of the Internet of things (IoT), such as massive volume of data, stringent resource constraints, and heterogeneous activity levels, future wireless IoT infrastructures must integrate smart self-organizing solutions to efficiently operate in the dynamic IoT environment.Within this context, this thesis presents the development of innovative integrated reconfigurable antenna systems capable of adapting to such dynamic and multi-purposed wireless IoT networks.As a first step, the thesis covers the design of antennas suitable for integration in IoT terminals when specific radiation properties or multi-band operations are needed. Both antenna structures and integration techniques are presented for single and multi-band IoT applications. Next, a design methodology based on a multi-access single structure antenna and a miniaturized omnidirectional circularly polarized antenna for IoT applications are presented. Successively, an approach based on Neural Networks (NN) to estimate the performance of small antennas given practical constraints is presented. As proof of concept, the case of printed antennas integrated into compact terminals is considered.In the second part, the thesis focuses on the development of compact and low-power-consuming reconfigurable antennas. In order to enable new applications, such as wearable communications, and to deliver higher performance in a variety of integration environments, a flexible, reconfigurable antenna is presented. To guarantee reliable operation, flexible antennas must maintain proper electrical or radiation characteristics despite the variation of their structure given by the flexibility. Consequently, the reconfiguration mechanism of the proposed antenna allows the shift of the antenna resonance, making the antenna capable of maintaining an acceptable impedance matching over the operating band even when the antenna is folded.A compact high gain and front-to-back ratio pattern reconfigurable antenna for spatial filtering in IoT networks is then proposed. The reconfiguration mechanism is based on the use of a low-insertion, low-on resistance SP4T switch, which can be numerically controlled by a microcontroller, as required by IoT applications. Successively, a slot-based electronically steerable parasitic array radiator (ESPAR) antenna suitable for IoT applications is presented. The work describes in-depth the design procedure of the antenna, addressing the practical implementation of the reconfiguration mechanism, and focusing on the realization of the prototype and its experimental evaluation.Finally, a methodology for synthesizing parasitic antenna arrays is proposed. The method is based on the use of a Particle Swarm Optimizer (PSO), which iteratively optimizes the parasitic element loads until the desired pattern behavior is obtained. In order to assess the method's ability to address the desired goals, the methodology is used to optimize the directivity, the front-to-back ratio, and the gain of compact parasitic array antennas for IoT devices. The impedance loads values identified with this approach are integrated into the antenna structures to realize the parasitic antenna array. Reconfiguration can then simply be obtained by rotating the load's values over the parasitic elements
Tsai, Chih-Wei, and 蔡志偉. "Pattern Reconfigurable Antenna Designs Using Sector Arrays." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/23767849458852298644.
Повний текст джерела國立彰化師範大學
電機工程學系
104
A design for beam steering antenna arrays is described. The radiating element of the array is mainly composed of dual coplanar slotted-patch antennas, a metallic reflector, and several PIN diodes embedded in the slots. By controlling the states of the diodes, the operation of the slotted-patch antennas can be switched among three modes. These operation modes can generate three radiation beams respectively directed to ɸ = 0°, 40°, and −40° in the H-plane. Based on the pattern reconfigurable antenna element, a three-sector triangular array operated at 2.2 GHz is developed. The measured results demonstrate that the sector array can provide nine radiation beams which are steerable over a full 360° in the azimuthal plane; in addition, each switched beam has a half-power beamwidth of about 60° and a cross polarization level of lower than -20 dB. In the other hand, a linear array operated at 2.2 GHz is developed. The measured results demonstrate that the gains of three modes have 10.7 dB almost. Compared with simulated results, it has less than 3.5 dB. The main reason of losses is ohmic and transmission. A design for arrays with beam-steering capability in the azimuthal plane is described. The array is a four-sector antenna configuration,and each sector element can generate unidirectional radiation with circular polarization (CP). A reconfigurable 1 × 4 power divider with broadband operation is designed and used to excite the sector elements. By controlling PIN diodes, the divider can offer 11 states for the four outputs, and each state is corresponding to one CP radiation pattern of the array. Prototypes for the sector array and the tunable divider are, respectively, constructed, and the experimental results of the integrated structure demonstrate that, in addition to the beam-steering capability, the array can also generate bidirectional and omnidirectional radiation patterns between 1.9 and 2.3 GHz. Moreover, these steerable beams and radiation patterns have a cross polarization of less than −18 dB for all azimuthal angles.
Markley, Loic. "Subwavelength Imaging using Scanning Near-field Antenna Arrays." Thesis, 2013. http://hdl.handle.net/1807/65518.
Повний текст джерелаHerd, Jeffrey Scott. "Scanning impedance of proximity-coupled rectangular microstrip antenna arrays." 1989. https://scholarworks.umass.edu/dissertations/AAI9011739.
Повний текст джерелаChang, Ralph, and 張希喆. "Ku-Band Phase-Shifterless Beam-Scanning Active Antenna Arrays." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/89099995765311103130.
Повний текст джерела國立交通大學
電信研究所
85
This project is to design, fabrication and measure the Ku-band phase-shifterless beam-scanning active antenna arrays. The beam scanning in linear arrays of antenna-coupled oscillators can operate at desired frequency range with in-phase and stable, then the end elements be slightly detuning frequency to provide continuously phase variation between the elements without phase shifter. Mutual coupling technique is utilized to enable them to synchronize to a common frequency through the phenomenon of injectionThis project is based on the circuit designed by Dr. York*s group of UCSB and Prof. Itoh*s group. In this phase- shifterless beam-scanning antennas arrays, it was shown that a constant phase progression can be established by slightly detuning the peripheral arrays elements, while maintaining mutual synchronization.An experiment for the beam-scanning antenna arrays has been carried out. The oscillation frequency is measured at about 16.7 GHz. It has continuously scan the radiation pattern from . An effective radiation power (ERP) of 85mW、349mW、1789mW is obtained for single-unit, two-unit and four-unit active antenna array.
Wang, Jing-Wen, and 王敬文. "Reconfigurable Hybrid Beamforming System with Dual-Polarized Phase Antenna Arrays in mmWave Channels." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/56922216989921905289.
Повний текст джерела國立交通大學
電信工程研究所
105
This thesis studies the reconfigurable hybrid beamforming architecture with dual-polarized phased antenna arrays for millimeter wave (mmWave) communication systems. Traditionally, to implement a MIMO antenna array system, every single antenna requires a RF chain which is a very expensive and high power consumption approach to achieve large-scale multi-antenna array system. In contrast, the hybrid beamforming architecture is a rather cost-effective option since less RF chains are needed. Besides, it not only compensates high path loss in mmWave, but also exploits the degree of freedom in signal processing. Furthermore, we use dual-polarized patch antenna to reduce the effect from the dead zone of single-polarized patch antenna and from the high spatial correlation issue in mmWave communication systems. For the traditional fixed hybrid beamforming system, the connecting of RF chains and antenna arrays is fixed. When the channel conditions or the positions of users change, the system may not achieve the best quality of communication. Based on the traditional architecture, this thesis proposes a reconfigurable hybrid beamforming architecture. Combine the analog multiplexers between RF chains and antenna arrays, let it can dynamically adjust the connecting of RF chains and antenna arrays and conduct space-time code or spatial multiplexing and design their corresponding baseband precoder. Finally, design a training flow to let the system can choose the best operating mode. By the simulation results, the system will adjust to the best operating modes according to the training flow for different channel conditions and the capacity will significantly increase. Comparing with the fixed architecture, the reconfigurable one is more flexible and has another degree of freedom to increase the capacity. For the next generation mobile communication, it is one of the potential techniques.
Szazynski, Mitchel H. "Wireless power transfer: a reconfigurable phased array with novel feeding architecture." Thesis, 2018. https://doi.org/10.7912/C24H2M.
Повний текст джерелаThis thesis proposes a reconfigurable phased array of antennas for wireless power transfer. The array finds use in many applications, from drone destruction (for defense) to wireless charging of robots and mobile devices. It utilizes a novel feeding architecture to greatly reduce the number of high cost elements (such as amplifiers and phase shifters) as well as the quantity of unused resources in the system. Upon the instruction of the CPU, the array can separate into any number of subarrays, each of which transmits power to a single receiver, steering its beam as the receiver changes location. Currently dormant elements in the array can be used to provide position information about the receivers, either via Radar, or by listening for beacons pulses from the receiver. All of this is made possible, with only 4 amplifiers and 3 phase shifters, by the proposed 4-Bus Method. The source signal is divided into four buses, which are respectively phase shifted by 270 degrees, 180 degrees, 90 degrees, and 0 degrees (no shifter required) and then amplified. The CPU calculates, based on the number and positions of the receivers / targets, what the amplitude and phase excitation must be at each element. Any phase and amplitude which could be required can be achieved by simply adding together appropriate quantities of the correct two buses. In order to achieve this, the key piece is the variable power divider. These differ from Wilkinson dividers in that the dividing ratio can be changed via an applied DC voltage. Therefore, at each junction, by properly diverting the power levels on each phase bus to their proper location, complete delocalization of both amplifiers and phase shifters can be achieved. A method has also been developed which helps overcome the limitations of each variable power divider. That is, in certain instances, it may be desirable to pass all the power to a single output port or the other, which is not a possibility inherently possible with the device. With the use of a unique combination of RF switches, the nodes achieve much enhanced flexibility. Finally, an intensive study is carried out, in an attempt to yield greater understanding, as well as quick, useful approximations, of the behaviors of both rectangular and hexagonal arrays of various sizes and beam steering angles for wireless power.
Kim, Chan Ho. "Reconfigurable Microstrip Bandpass Filters, Phase Shifters Using Piezoelectric Transducers, and Beam-scanning Leaky-wave Antennas." Thesis, 2012. http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-10835.
Повний текст джерелаAlibakhshikenari, M., B. S. Virdee, P. Shukla, C. H. See, Raed A. Abd-Alhameed, M. Khalily, F. Falcone, and E. Limiti. "Interaction between closely packed array antenna elements using metasurface for applications such as MIMO systems and synthetic aperture radars." 2018. http://hdl.handle.net/10454/16635.
Повний текст джерелаThe paper presents a technique to enhance the isolation between adjacent radiating elements which is common in densely packed antenna arrays. Such antennas provide frequency beam-scanning capability needed in Multiple-Input Multiple-Output (MIMO) systems and Synthetic Aperture Radars (SARs). The method proposed here uses a metamaterial decoupling slab (MTMDS), which is located between radiating elements, to suppress mutual-coupling between the elements that would otherwise degrade the antenna efficiency and performance in both the transmit and receive mode. The proposed MTM-DS consists of mirror imaged Eshaped slits engraved on a microstrip patch with inductive stub. Measured results confirm over 9–11 GHz with no MTM-DS the average isolation (S12) is -27 dB; however, with MTM-DS the average isolation improves to -38 dB. With this technique the separation between the radiating element can be reduced to 0.66λo, where λ0 is free space wavelength at 10 GHz. In addition, with this technique there is 15% improvement in operating bandwidth. At frequencies of high impedance match of 9.95 GHz and 10.63 GHz the gain is 4.52 dBi and 5.40 dBi, respectively. Furthermore, the technique eliminates poor front-to-back ratio encountered in other decoupling methods. MTM-DS is also relatively simple to implement. Assuming adequate space is available between adjacent radiators the MTM-DS can be fixed retrospectively on existing antenna arrays, which makes the proposed method versatile.
Partially supported by innovation programme under grant agreement H2020-MSCA-ITN-2016 SECRET- 722424 and the financial support from the UK Engineering and Physical Sciences Research Council (EPSRC) under grant EP/E022936/1.