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 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 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 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 Analysis and Design of Transmitarray Antennas written by Ahmed H. Abdelrahman and published by Springer Nature. This book was released on 2022-06-01 with total page 151 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 Elizabeth Baker Dowd Collection written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Collection contains clipping file.

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 Handbook of Reflector Antennas and Feed Systems Volume I Theory and Design of Reflectors written by Satish K. Sharma and published by Artech House. This book was released on 2013-07-01 with total page 323 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first truly comprehensive and most up-to-date handbook available on modern reflector antennas and feed sources for diversified space and ground applications. There has never been such an all-encompassing reflector handbook in print, and no currently available title offers coverage of such recent research developments. The Handbook consists of three volumes. Volume I provides a unique combination of theoretical underpinnings with design considerations and techniques. The need for knowledge in reflector antennas has grown steadily over the last two decades due to increased use in space and ground applications, as well as their high gain and wide bandwidth capabilities at relatively low cost. This volume brings you to the leading edge of developments in the field related to numerical techniques, classical reflector geometries, adaptive reflector antennas, shaped reflectors, bifocal and bicollimated dual reflectors, advanced reflectors, and reflect arrays. A must-have reference for both practicing engineers as well as academic researchers.

Download or read book Reflectarray Performance Improvement Using the Element Spacing Reduction Technique written by Faezeh Safari and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents the design, analysis and performance improvement of reflectarray (RA) antennas. The considered RA consists of a feed antenna and an array of 'small' elements that are distributed on a flat surface using printed circuit technology. The feed antenna is used to generate an incident field to illuminate the elements of the RA. Each element acts as a partial reflector with a specific reflection coefficient. The resulting reflected field on the RA aperture should have the desired amplitude and phase distribution to create the antenna`s far field radiation pattern. The RA element reflection coefficient versus its geometrical parameters in a uniform infinite array environment is used as a data table to design the RA elements. The RA element geometry is comprised of a simple rectangular patch on the top of a at single-layer grounded dielectric substrate. Reflectarray technology suffers from several degrading factors such as low efficiency and gain bandwidth. In this thesis it is shown that as the element spacing reduces, a better control over the RA aperture is achieved. This improves the efficiency of the RA. Also, as the element spacing reduces, the reflection coefficient phase versus frequency becomes more linear. This improves the gain bandwidth of the RA. The beam squint, which is the deviation of the RA beam angle from the desired beam angle, is another degrading factor of the RA technology. Only a few attempts have been made in the literature to investigate or reduce the RA beam squint. These attempts are either incomplete or complicated. In this thesis, it is shown that as the element spacing reduces the beam squint of the RA improves. It is also shown that as the element spacing reduces the side lobe level and cross-polarization of the RA improves. These two far field parameters are important but not investigated in the literature. Sixteen RA designs and associated analyses are presented. One design was selected for fabrication utilizing a feed antenna from the University of Manitoba's Antenna Laboratory. The measured radiation patterns agree well with the analysis results and demonstrate the validity of the element spacing reduction technique.

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 Analysis and Design of Reflectarray Antennas for Radar System Applications written by Yu Pan and published by . This book was released on 2014 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Antenna Engineering Handbook written by John Volakis and published by McGraw Hill Professional. This book was released on 2018-11-05 with total page 1424 pages. Available in PDF, EPUB and Kindle. Book excerpt: The gold-standard reference on the design and application of classic and modern antennas—fully updated to reflect the latest advances and technologiesThis new edition of the “bible of antenna engineering” has been updated to provide start-to-finish coverage of the latest innovations in antenna design and application. You will find in-depth discussion of antennas used in modern communication systems, mobile and personal wireless technologies, satellites, radar deployments, flexible electronics, and other emerging technologies, including 5G, terahertz, and wearable electronics. Antenna Engineering Handbook, Fifth Edition, is bolstered by real-world examples, hundreds of illustrations, and an emphasis on the practical aspects of antennas.Featuring 60 chapters and contributions from more than 80 renowned experts, this acclaimed resource is edited by one of the world’s leading antenna authorities. This edition features all of the classic antenna types, plus new and emerging designs, with 13 all-new chapters and important updates to nearly all chapters from past editions.Antenna Engineering Handbook, Fifth Edition, clearly explains cutting-edge applications in WLANs, automotive systems, PDAs, and handheld devices, making it an indispensable companion for today’s antenna practitioners and developers.Coverage includes:•Antenna basics and classic antennas•Design approaches for antennas and arrays•Wideband and multiband antennas•Antennas for mobile devices and PDAs, automotive applications, and aircraft•Base station and smart antennas•Beamforming and 5G antennas•Millimeter-wave and terahertz antennas•Flexible, wearable, thin film, origami, dielectric, and on-chip antennas•MIMO antennas and phased arrays•Direction-finding and GPS antennas•Active antennas•Low-profile wideband antennas•Nanoantennas•Reflectors and other satellite and radio-telescope antennas•Low-frequency, HF, VHF, UHF, ECM, and ESM antennas•Impedance-matching techniques and material characteristics•Metastructured and frequency selective surfaces•Propagation and guided structures•Computational techniques and toolsets•Indoor and outdoor measurements

Download or read book Array and Phased Array Antenna Basics written by Hubregt J. Visser and published by John Wiley & Sons. This book was released on 2006-02-03 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reflecting a growing interest in phased array antenna systems, stemming from radar, radio astronomy, mobile communications and satellite broadcasting, Array and Phased Array Antenna Basics introduces the principles of array and phased array antennas. Packed with first-hand practical experience and worked-out examples, this is a valuable learning tool and reference source for those wishing to improve their understanding of basic array antenna systems without relying heavily on a thorough knowledge of electromagnetics or antenna theory. Features a general introduction to antennas and explains the array antenna principle through discussion of the physical characteristics rather than the theory Explores topics often not covered in antenna textbooks, such as active element pattern, array feeding, means of phase changing, array antenna characterisation, sequential rotation techniques and reactively loaded arrays Guides the reader through the necessary mathematics, allowing them to move onto specialist books on array and phased array antennas with a greater understanding of the topic Supported by a companion website on which instructors and lecturers can find electronic versions of the figures An ideal introduction for those without a background in antennas, this clear, concise volume will appeal to technicians, researchers and managers working in academia, government, telecommunications and radio astronomy. It will also be a valuable resource for professionals and postgraduates with some antenna knowledge.

Download or read book Millimeter Wave Antennas Configurations and Applications written by Jaco du Preez and published by Springer. This book was released on 2016-06-20 with total page 165 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book comprehensively reviews the state of the art in millimeter-wave antennas, traces important recent developments and provides information on a wide range of antenna configurations and applications. While fundamental theoretical aspects are discussed whenever necessary, the book primarily focuses on design principles and concepts, manufacture, measurement techniques, and practical results. Each of the various antenna types scalable to millimeter-wave dimensions is considered individually, with coverage of leaky-wave and surface-wave antennas, printed antennas, integrated antennas, and reflector and lens systems. The final two chapters address the subject from a systems perspective, providing an overview of supporting circuitry and examining in detail diverse millimeter-wave applications, including high-speed wireless communications, radio astronomy, and radar. The vast amount of information now available on millimeter-wave systems can be daunting for researchers and designers entering the field. This book offers readers essential guidance, helping them to gain a thorough understanding based on the most recent research findings and serving as a sound basis for informed decision-making.

Download or read book Dielectric Resonator Antennas written by Kwai Man Luk and published by Research Studies Press Limited. This book was released on 2003 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of dielectric resonator as a resonant antenna was proposed in 1983. Due to the absence of metallic loss, the dielectric resonator antenna (DRA) is highly efficient when operated at millimetre wave frequencies. With the use of high dielectric constant material, the DRA can also be used as a small and low profile antenna operated at low microwave frequencies. Low cost dielectric materials are now easily available commercially, encouraging more antenna engineers to design communication systems with DRAs.

Download or read book Handbook of Reflector Antennas and Feed Systems Volume III Applications of Reflectors written by Sudhakar Rao and published by Artech House. This book was released on 2013-06-01 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first truly comprehensive and most up-to-date handbook available on modern reflector antennas and feed sources for diversified space and ground applications. There has never been such an all-encompassing reflector handbook in print, and no currently available title offers coverage of such recent research developments. The Handbook consists of three volumes. Volume III focuses on the range of reflector antenna applications, including space, terrestrial, and radar. The intent of this book volume is to provide practical applications and design information on reflector antennas used for several communications systems. This book covers recent developments of reflector antennas used for satellite communications, terrestrial communications, and remote sensing applications. New subjects are introduced for the first time, including satellite antennas, Terahertz antennas, PIM, multipaction, corona, deployable mesh reflector antennas, and mechanical aspects of reflector antennas. In addition, this book contains a separate topic on integrated feed assembly for reflector antennas covering analysis, design, fabrication, and test.