Download or read book Reconfigurable Reflectarray Antennas with Bandwidth Enhancement for High Gain Beam steering Applications written by Michael E. Trampler and published by . This book was released on 2019 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt: In chapter 4, the array performance of the dual-resonance unit cell is analyzed. The effects of varying angles of incidence on the array element are studied using Floquet simulations. The beam scanning, cross-polarization and bandwidth performance of a 7x7 element reflectarray is analyzed using full-wave simulations and verified via measurements.

Download or read book Broadband Approaches and Beam scanning Techniques for Reflectarray Antenna written by Yilin Mao and published by . This book was released on 2014 with total page 213 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reflectarray antennas combine the numerous advantages of reflector antennas and phased array antennas and create a hybrid high-gain antenna with a low-profile, low-mass, easy-fabrication, and diversified radiation performance. However, it still has some inherent drawbacks, such as limited bandwidth and scanning range, which are targeted in this dissertation.At first, the array theory approach for radiation analysis of reflectarray antennas is described and implemented. Numerical results are then presented and compared with reference results to confirm its reliability. As the most critical influential factor to the reflectarray bandwidth, the element bandwidth was studied at first, and the effects of element shape and substrate thickness were investigated. Then, a comprehensive study was performed to investigate the bandwidth performance of reflectarrays on the system level. The effect of aperture size, element bandwidth and phase synthesis method was discussed in sequence. Particularly, a novel phase synthesis approach was proposed, which enables reflectarray to achieve a significant bandwidth improvement even with elements of narrow bandwidth. Prototypes are fabricated and tested to validate the idea. Since the reflectarray antenna is a hybrid product of reflector and phased array antennas, its main beam could be steered by either rotating its feed or reconfiguring its element phases. The former way was explored at first. An improved phase design was proposed for reflectarrays mimicing parabolic-cylindrical reflectors to expand its scanning range. The published achievements of reconfigurable reflectarrays design are reviewed and it is found that currently efficiency is a big problem. A 1-bit 10×10 reconfigurable reflectarray using PIN diode was designed, fabricated and measured to explore the energy loss, and experimental results showed that 14% efficiency could be reached. In summary, some improved designs regarding bandwidth and scanning performance for reflectarrays are proposed in this dissertation. Various factors affecting reflectarray bandwidth are investigated, which shall provide some guidelines regarding bandwidth improvement. On the other hand, two designs are presented to explore the beam scanning characteristic of reflectarray antenna, by mechanical and electrical ways respectively. Several prototypes have been fabricated and measured, demonstrating the novel features and potential applications of reflectarray antennas.

Download or read book Beam steerable and Reconfigurable Reflectarray Antennas for High Gain Space Applications written by Kalyan K. Karnati and published by . This book was released on 2015 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reflection coefficients over a 749-element reflectarray aperture for a broadside radiation pattern are presented for a couple of cases and the effects of coupling conditions in conjunction with incidence angles are demonstrated. The presented theory provides explicit physical intuition and guidelines for efficient and accurate reflectarray design. In chapter 4, tunable reflectarray elements capacitively loaded with Barium Strontium Titanate (BST) thin film are shown. The effects of substrate thickness, operating frequency and deposition pressure are shown utilizing coupling conditions and the performance is optimized. To ensure minimum affects from biasing, optimized biasing schemes are discussed. The proposed unit cells are fabricated and measured, demonstrating the reconfigurability by varying the applied E-field. To demonstrate the concept, a 45 element array is also designed and fabricated. Using anechoic chamber measurements, far-field patterns are obtained and a beam scan up to 25° is shown on the E-plane. Overall, novel theoretical approaches to analyze the reflection properties of the reflectarray elements using Q factors are developed. The proposed theoretical models provide valuable physical insight utilizing coupling conditions and aid in efficient reflectarray design. In addition, for the first time a continuously tunable reflectarray operating at Ka-band is presented using BST technology. Due to monolithic integration, the technique can be extended to higher frequencies such as V-band and above.

Download or read book Reflectarray Antennas written by Payam Nayeri and published by John Wiley & Sons. This book was released on 2018-02-20 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides engineers with a comprehensive review of the state-of-the-art in reflectarray antenna research and development. The authors describe, in detail, design procedures for a wide range of applications, including broadband, multi-band, multi-beam, contour-beam, beam-scanning, and conformal reflectarray antennas. They provide sufficient coverage of basic reflectarray theory to fully understand reflectarray antenna design and analysis such that the readers can pursue reflectarray research on their own. Throughout the book numerous illustrative design examples including numerical and experimental results are provided. Featuring in-depth theoretical analysis along with practical design examples, em style="mso-bidi-font-style: normal;"Reflectarray Antennas is an excellent text/reference for engineering graduate students, researchers, and engineers in the field of antennas. It belongs on the bookshelves of university libraries, research institutes, and industrial labs and research facilities.

Download or read book Reconfigurable Antennas written by Jennifer T. Bernhard and published by Morgan & Claypool Publishers. This book was released on 2007-12-01 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt: This lecture explores the emerging area of reconfigurable antennas from basic concepts that provide insight into fundamental design approaches to advanced techniques and examples that offer important new capabilities for next-generation applications. Antennas are necessary and critical components of communication and radar systems, but sometimes their inability to adjust to new operating scenarios can limit system performance. Making antennas reconfigurable so that their behavior can adapt with changing system requirements or environmental conditions can ameliorate or eliminate these restrictions and provide additional levels of functionality for any system. For example, reconfigurable antennas on portable wireless devices can help to improve a noisy connection or redirect transmitted power to conserve battery life. In large phased arrays, reconfigurable antennas could be used to provide additional capabilities that may result in wider instantaneous frequency bandwidths, more extensive scan volumes, and radiation patterns with more desirable side lobe distributions. Written for individuals with a range of experience, from those with only limited prior knowledge of antennas to those working in the field today, this lecture provides both theoretical foundations and practical considerations for those who want to learn more about this exciting subject. Contents: Introduction / Definitions of Critical Parameters for Antenna Operation / Linkage Between Frequency Response and Radiation Characteristics: Implications for Reconfigurable Antennas / Methods for Achieving Frequency Response Reconfigurability / Methods for Achieving Polarization Reconfigurability / Methods for Achieving Radiation Pattern Reconfigurability / Methods for Achieving Compound Reconfigurable Antennas / Practical Issues for Implementing Reconfigurable Antennas / Conclusions and Directions for Future work

Download or read book Advanced Design Methodologies and Novel Applications of Reflectarray Antennas written by Payam Nayeri and published by . This book was released on 2012 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reflectarray antennas combine the numerous advantages of printed antenna arrays and reflector antennas and create a hybrid high-gain antenna with a low-profile, low-mass, and diversified radiation performance. Reflectarrays are now emerging as the new generation of high-gain antennas for long-distance communications. In this dissertation, some advanced concepts demonstrating novel features of reflectarray antennas are presented. * First, various approaches for radiation analysis of reflectarray antennas are described and implemented. Numerical results are then presented for a variety of systems and the advantages, limitations, and accuracy of these approaches are discussed and compared with each other. * A broadband technique by using sub-wavelength elements is proposed and prototypes are fabricated and tested. This technique enables the reflectarray to achieve a significant bandwidth improvement with no additional cost. * Infrared reflectarrays antennas are studied for possible applications in concentrating solar power systems. Material losses, an important design issue at infrared frequencies, are investigated and reflectarrays consisted of dielectric resonant elements are proposed with low-loss features at infrared. * Multi-beam reflectarray antennas are studied and it is demonstrated that by optimizing the phase of the elements, a desirable multi-beam performance can be achieved using a single-feed. Local and global phase-only optimization techniques have been implemented. Two Ka-band quad-beam prototypes with symmetric and asymmetric beams have been fabricated and tested. * Different approaches for beam-scanning with reflectarray antennas are also reviewed and it is shown that for moderately wide angle beam-scanning, utilizing a feed displacement technique is more suitable than an aperture phase tuning approach. A feed displacement beam-scanning design with novel aperture phase distribution is proposed for the reflectarray antenna, and is further optimized to improve the performance. A high-gain Ka-band prototype achieving 60 degrees scan range with side-lobe levels below 15 dB is demonstrated. * The feasibility of designing reflectarray antennas on conformal surfaces is also studied numerically. A generalized analysis approach is presented and the radiation performance of reflectarray antennas on singly-curved conformal cylindrical platforms are studied and compared with their planar counterpart. It is revealed that conformal reflectarray antennas are a suitable choice for a high-gain antenna where curved platforms are required. In summary, different challenges in reflectarray analysis and design are addressed in this dissertation. On the element design challenges, bandwidth improvement and infrared operation of reflectarray antennas have been studied. On the system level challenges, multi-beam designs, beam-scanning performance, and conformal platforms have been investigated. Several prototypes have been fabricated and tested, demonstrating the novel features and potential applications of reflectarray antennas.

Download or read book Reflectarray Antennas Analysis Design Fabrication and Measurement written by Jafar Shaker and published by Artech House. This book was released on 2013-11-01 with total page 237 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reflectarray antennas refer to the class of radiating structures that are comprised of an array of radiating elements, re-radiating the energy that is impinged on them from one or more radiating feeds that are located in free space. The constituent radiators that build a reflectarray can be shaped to bring about some flexibility in the way that antenna operates such as multi band/polarization operation. The printed nature of these elements allow integration of active elements that can further enhance the functionality of the reflectarray. This allows for capabilities such as power amplification, adaptive beam shaping, and beam switching. This resource presents readers with design guidelines along with an ample amount of material on different types of reflectarrays and methods of analysis. This book begins with introductory material on reflectarray antennas and progresses to the presentation of state-of-the-art research in the field. A direct comparison with conventional reflector antennas is provided, focusing on conventional efficiency figures of reflectors. Moreover, this book offers remarks on the future direction of reflectarray research and also potential applications of the technology in face of the emergence of new fabrication techniques to accommodate both passive and active elements.

Download or read book Reflectarray Antennas written by John Huang and published by John Wiley & Sons. This book was released on 2007-11-09 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: Describes the configuration and principles of a reflectarray antenna, its advantages over other antennas, the history of its development, analysis techniques, practical design procedures, bandwidth issues and wideband techniques, as well as applications and recent developments. Both authors are well respected practitioners who have build these antennas and developed them for space flight.

Download or read book Dual band Beam Scanning Reflectarrays and Novel Wideband and Polarization Diversified Planar Antennas written by Shih-Hsun Hsu and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The reflectarray antenna has been considered as a suitable candidate to replace the traditional parabolic reflectors because of its high-gain and low-profile features. Beam scanning capability and multi-band operation are the current trends of the reflectarray design. It is desired to implement these functionalities with simple and effective techniques. Narrow bandwidth is the main issue which restricts the applications of the microstrip antennas. New microstrip slot antennas and polarization diversified planar antennas are introduced as the solutions to the issue of narrow bandwidth in this dissertation. A dual-band beam scanning reflectarray has been developed. It is the first offset-fed reflectarray that has been ever practically developed to emulate a cylindrical/parabolic type of reflector. Unlike other beam scanning reflectarrays which integrate phase tuning devices into the reflectarray elements and control the reflection phase, the beam scanning capability of this reflectarray is provided by its feed array. This method significantly reduces the complexity of the design of the beam scanning reflectarray. A new dual-band reflectarray configuration is also developed to eliminate the possible top layer blocking effects in the dual-layer reflectarray configuration. Perforated patches loaded with slots on the ground plane and rectangular patches loaded with slots on the patches are adopted as the low and high frequency bands, respectively. It is guaranteed that no physical contact between any two elements will occur. The bandwidth of the conventional microstrip antenna is small. A new wideband circularly polarized microstrip slot antenna is introduced in this dissertation. Very wide 3-dB axial ratio bandwidth is observed for the proposed antenna. The antennas are assembled in triangularly arranged array with sequential rotation feed technique. Polarization polarity is an alternative solution to the narrow bandwidth. A reconfigurable circularly polarized microstrip antenna is proposed. The antenna has both right-hand and left-hand circular polarizations which are controlled by two piezoelectric transducers. In addition, a dual-band dual-linearly-polarized planar array is designed based on the concepts of polarization diversity and multi-band operation. The research presented in this dissertation suggests useful techniques for reflectarrays and novel antenna designs. The results should have many applications for the modern wireless communication and radar systems.

Download or read book Analysis and Design of Reflectarray Antennas for Bandwidth Enhancement Feed Matching and Portability written by Muhammad Mustafa Tahseen and published by . This book was released on 2017 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reflectarray (RA) antennas are introduced as an alternative to the conventional parabolic reflectors and antenna arrays. The RA provides the advantages of both reflectors and arrays. The narrow bandwidth is one of the distinct disadvantages of RA. The RA bandwidth is primarily limited by two factors, the element bandwidth, and the spatial phase delay. As the RA size is fixed with a proper focal distance, the second factor is hard to be used in the RA bandwidth optimization. It is impossible to design a broadband RA using narrowband elements, so wideband elements are developed in a unit cell of a periodic structure to further provide wider overall antenna bandwidth. In the literature review, 10-15 % RA bandwidth has been observed, which is mainly because of the used narrowband elements.Several RA antennas operating in the Ka-Band are designed and fabricated to learn an understanding of the RA with wideband characteristics. New wideband elements for linear polarization (LP) and circular polarization (CP) are utilized. A bandwidth of 22 % in LP-RA antennas is achieved using the proposed wideband elements. Over 50 % gain, and 50 % axial ratio bandwidth, and 57-62 % maximum aperture efficiency are experimentally measured for the CP. The effect of the edge diffraction on the phase correction is also investigated. The initial study showed little effect, but the considered RA size is small to highlight this effect. The matching of the feed is deteriorated when placed in front of the reflector. Therefore, few methods are implemented to improve the antenna reflection coefficients. The experimental results show possible improvements.The proposed work is categorized into three Parts. Part A provides a comprehensive study of the wideband element designs for both LP- and CP-RA. Part B utilizes the wideband elements developed in Part A, in the RA environment and introduces the performance of the antenna. In part C, textile-reflectarray (TRA) is proposed using conductive thread and shielded fabric, which is the first to be considered as a new trend in the field of RA. The element analysis and measurements show promising results. However, when implemented in the RA, the shielded fabric does not perform as expected. This problem is resolved by introducing a dual-sided embroidered reflectarray antenna where a flexible frequency selective surface (FSS) embroidered at the textile material using a conductive thread is used at the back side of the radiating elements replacing the ground plane. The measured results of the first ever built flexible, portable textile-RA show good antenna performance. An FSS based flexible portable and rollable circularly polarized TRA design is also presented using the wideband cross Bowtie elements. The radiating elements are embroidered using conductive thread.The initial results exhibit good performance of the proposed CP TRA antenna. For RA with small f/D, the spatial delay problem is the main reason for limiting the bandwidth even with wideband RA elements. This issue is solved by introducing a new split aperture into panels that reduce the difference in the path length between the center and those away towards the RA edge. This method shows a significant improvement in the RA bandwidth.

Download or read book Beam Steerable Antennas for CubeSats written by Junbo Wang and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The advent of low-cost and lightweight CubeSats has opened up new possibilities to realize the Internet of Space (IoS), a vision that aims to establish a constellation of CubeSats in space to provide global network access. A key challenge for IoS realization is the development of beam steerable antennas that can meet the gain, bandwidth, and polarization requirements for IoS while complying with the small form factor of CubeSats. This work addresses this challenge by proposing innovative synthesis and implementation methods for reflectarrays and transmitarrays to empower low-profile wideband circularly-polarized (CP) beam steerable antennas. Two unique steerable antenna architectures are presented. The first design is a K-band mechanically steerable Risley prism antenna (RPA) constructed by two co-axially placed panels, i.e., a gradient-phase feed array (GPFA), and a gradient-phase transmitarray (GPTA). The in-plane rotation of the two panels creates beam scan that covers 0 - 360 in azimuth and 0 - 60 in elevation. To improve the CP bandwidth, a hybrid-phasing method is applied to design the GPFA, and an S-ring element unit cell is designed for the GPTA. The second design is an electronically steerable reflectarray antenna. Each unit cell can implement switches to reconfigure the connections among multiple Archimedean spiral arms, creating ``element rotation'' that leads to geometrically dependent CP phase shift. This allows the reflectarray to achieve wideband CP beam steering without any moving parts. Both antennas have been validated through prototypes and measurements to demonstrate their beam scanning capability and bandwidth potentials for CubeSat applications. Besides, a generalized design methodology for switch-reconfigured unit cells (SRUC) to achieve the maximum phase resolution is established. It applies binary particle swarm optimization (BPSO) algorithm to optimize the topology of pixelated unit cells with embedded switches. Unconventional linearly-polarized (LP) and CP 2-switch 4-state SRUC for K-band beam steerable reflectarrays have been designed and thoroughly validated. Lastly, the novel charge-programmed multi-material (CPMM) additive manufacturing technology is applied to innovate antenna design and fabrication. Several ultra-lightweight CP transmitarrays achieving order-of-magnitude weight reduction and a compact CP horn antenna with uniquely designed 3D structures have been manufactured and measured. This dissertation addresses the cutting edges of CubeSat beam steerable antennas from several aspects, including the fundamental principles, synthesis methods, antenna architectures, and manufacturing methods.

Download or read book Aperture Antennas for Millimeter and Sub Millimeter Wave Applications written by Artem Boriskin and published by Springer. This book was released on 2017-09-05 with total page 494 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the technology of millimetre waves and Terahertz (THz) antennas. It highlights the importance of moderate and high-gain aperture antennas as key devices for establishing point-to-point and point-to-multipoint radio links for far-field and near-field applications, such as high data-rate communications, intelligent transport, security imaging, exploration and surveillance systems. The book provides a comprehensive overview of the key antenna technologies developed for the mm wave and THz domains, including established ones – such as integrated lens antennas, advanced 2D and 3D horn antennas, transmit and reflect arrays, and Fabry-Perot antennas – as well as emerging metasurface antennas for near-field and far-field applications. It describes the pros and cons of each antenna technology in comparison with other available solutions, a discussion supplemented by practical examples illustrating the step-by-step implementation procedures for each antenna type. The measurement techniques available at these frequency ranges are also presented to close the loop of the antenna development cycle. In closing, the book outlines future trends in various antenna technologies, paving the way for further developments. Presenting content originating from the five-year ESF research networking program ‘Newfocus’ and co-authored by the most active and highly cited research groups in the domain of mm- and sub-mm-wave antenna technologies, the book offers a valuable guide for researchers and engineers in both industry and academia.

Download or read book Analysis and Design of Transmitarray Antennas written by Ahmed H. Abdelrahman and published by Morgan & Claypool Publishers. This book was released on 2017-01-18 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, transmitarray antennas have attracted growing interest with many antenna researchers. Transmitarrays combines both optical and antenna array theory, leading to a low profile design with high gain, high radiation efficiency, and versatile radiation performance for many wireless communication systems. In this book, comprehensive analysis, new methodologies, and novel designs of transmitarray antennas are presented. Detailed analysis for the design of planar space-fed array antennas is presented. The basics of aperture field distribution and the analysis of the array elements are described. The radiation performances (directivity and gain) are discussed using array theory approach, and the impacts of element phase errors are demonstrated. The performance of transmitarray design using multilayer frequency selective surfaces (M-FSS) approach is carefully studied, and the transmission phase limit which are generally independent from the selection of a specific element shape is revealed. The maximum transmission phase range is determined based on the number of layers, substrate permittivity, and the separations between layers. In order to reduce the transmitarray design complexity and cost, three different methods have been investigated. As a result, one design is performed using quad-layer cross-slot elements with no dielectric material and another using triple-layer spiral dipole elements. Both designs were fabricated and tested at X-Band for deep space communications. Furthermore, the radiation pattern characteristics were studied under different feed polarization conditions and oblique angles of incident field from the feed. New design methodologies are proposed to improve the bandwidth of transmitarray antennas through the control of the transmission phase range of the elements. These design techniques are validated through the fabrication and testing of two quad-layer transmitarray antennas at Ku-band. A single-feed quad-beam transmitarray antenna with 50 degrees elevation separation between the beams is investigated, designed, fabricated, and tested at Ku-band. In summary, various challenges in the analysis and design of transmitarray antennas are addressed in this book. New methodologies to improve the bandwidth of transmitarray antennas have been demonstrated. Several prototypes have been fabricated and tested, demonstrating the desirable features and potential new applications of transmitarray antennas.

Download or read book An Active Reconfigurable Reflectarray Antenna written by Krishna Kumar Kishor and published by . This book was released on 2010 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis focuses on a type of antenna known as the reflectarray antenna. In particular, it looks at the design of an active reconfigurable reflectarray antenna, which has not received much attention in the reflectarray community. Potential applications include deployment as a high gain, reconfigurable antenna for communication links, and as a spatial power combiner. The reflectarray element is an aperture-coupled patch that accepts a linearly polarized wave, phase shifts and amplifies the guided-waves in the transmission lines, and then re-radiates an orthogonally polarized wave. Stability analysis of the element, experimental results of the designed phase shifter and simulation and experimental results of the element are presented. Fabrication details of a 48 element reflectarray and challenges faced during experimental characterization of the elements are also discussed. The two dimensional beamforming capability and amplifying nature of the array are successfully demonstrated and verified, indicating robustness to phase errors and oscillating elements.

Download or read book Near field Phase Transformation for Radiation Performance Enhancement and Beam Steering of Resonant Cavity Antennas written by Muhammad Usman Afzal and published by . This book was released on 2016 with total page 201 pages. Available in PDF, EPUB and Kindle. Book excerpt: Resonant-cavity antennas (RCAs) are promising candidates in advanced wireless applications because of their moderate-to-high gain, simple configuration, low and planar profile, and lack of feed networks. This dissertation presents novel mechanisms to enhance directivity and other radiation characteristics and to steer beam of RCAs. Solutions to both challenges are based on near-field phase transformation and have been demonstrated by designing metasurfaces for this transformation. A classical RCA comprising of a patch antenna and an unprinted all-dielectric superstructure is considered as the base antenna to assess the effectiveness of the proposed solutions. To enhance directive radiation characteristics, a near-field phase transformation methodology is developed to improve the uniformity of electric near-field phase distribution. This is realized by designing several phase-correcting structures/ surfaces (PCSs). This novel method employs electromagnetic (EM) simulators to accurately obtain a non-uniform phase distribution on the aperture of RCAs. Two different types of PCSs prototypes were developed. The first proof-of-concept prototype is an all-dielectric varying-height PCS with a stepped geometry, which corrects the phase at discrete points on the RCA aperture. Simulation and measurement results of the classical RCA with the PCS indicate that the PCS increases the peak directivity of the RCA by 9 dB (from 12.5 dBi to 21.2 dBi) and enhances its uniform aperture area by 178%. As an extension to this, a quasi-analytical approach is developed and is utilised to synthesise a continuous PCS for a circularly polarized ( CP) RCA. The performance of the continuous PCS is evaluated through numerical simulations, and predicted results indicate that the improvement in radiation performance is comparable to what was achieved with the former dielectric PCS. The second PCS prototype was a compact, lightweight design, which was implemented using printed phase-shifting elements. The planar PCS prototype is 57% lighter and is only 9% of the maximum height of the all-dielectric PCS prototype. The RCA with the planar PCS has the peak directivity of 20.5 dBi, which is 8 dB higher than that of without PCS. To address beam steering, a mechanism based on the rotation of a sawtooth time-delay (STD) metasurface pair is presented. The metasurface pair is physically located on the aperture of the RCA, in the near-field region for the purpose of phase transformation. Each metasurface was designed to create a STD in the propagating electric field so that the beam is tilted by an angle of 20°. The metasurface pair is rotated concurrently and independently, to move the beam to any direction in a conical region with a 92° vertex angle. As a technical demonstration, only a few angular positions were tested, however, the system is capable of scanning the whole angular space. The peak realized gain of 19.4 dBi was achieved in the broadside direction and the gain was 17.5 dBi when the beam was moved to the farthest elevation angle of 46°. The conspicuous attributes of the proposed beam-steering system are its extremely low-profile, which is 34.6 mm or 1.3;.\0, its passive nature, and its ability to maintain planar geometry during scanning. The proposed solution of near-field phase transformation successfully demonstrates radiation performance enhancements and beam steering of RCAs. Although the methodology was demonstrate for RCAs, this approach is applicable to other planar antennas and arrays.

Download or read book Analysis and Design of Simple Low Loss and Low Cost Reconfigurable Reflectarrays written by Bozhou Du and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the growing of wireless technology, the need for lower-profile, electronically reconfigurable, highly-directive beam-steering antennas is increasing. This thesis proposes a simple low loss, low cost electronic beam-steering antenna architecture by combining a variety of concepts including the single bit phase shifter, sub-wavelength element spacing and delta-sigma modulation. The starting point in the design of reflectarray antennas is the derivation of the so-called S-curve, which maps changes in unit cell design parameters to the phase of the scattered field from the cell. Both numerical and analytical techniques for analyzing linear-polarized fixed and reconfigurable reflectarray unit cell with lumped element has been developed. A 16 Ă 16 element reflectarray prototype operating at 5.5 GHz is presented the low loss performance and a beam-steering range of -20 to +20 degrees with a single bit phase shifter.

Download or read book Conformal Array Antenna Theory and Design written by Lars Josefsson and published by John Wiley & Sons. This book was released on 2006-02-10 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first comprehensive treatment of conformal antenna arrays from an engineering perspective. While providing a thorough foundation in theory, the authors of this publication provide a wealth of hands-on instruction for practical analysis and design of conformal antenna arrays. Thus, you get the knowledge you need, alongside the practical know-how to design antennas that are integrated into such structures aircrafts or skyscrapers.