Download or read book Antenna Shape Synthesis Using Characteristic Mode Concepts written by Jonathan L. T. Ethier and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Characteristic modes (CMs) provide deep insight into the electromagnetic behaviour of any arbitrarily shaped conducting structure because the CMs are unique to the geometry of the object. We exploit this very fact by predicting a perhaps surprising number of important antenna metrics such as resonance frequency, radiation efficiency and antenna Q (bandwidth) without needing to specify a feeding location. In doing so, it is possible to define a collection of objective functions that can be used in an optimizer to shape-synthesize antennas without needing to define a feed location a priori. We denote this novel form of optimization "feedless" or "excitation-free" antenna shape synthesis. Fundamentally, we are allowing the electromagnetics to dictate how the antenna synthesis should proceed and are in no way imposing the physical constraints enforced by fixed feeding structures. This optimization technique is broadly applied to three major areas of antenna research: electrically small antennas, multi-band antennas and reflectarrays. Thus, the scope of applicability ranges from small antennas, to intermediate sizes and concludes with electrically large antenna designs, which is a testament to the broad applicability of characteristic mode theory. Another advantage of feedless electromagnetic shape synthesis is the ability to synthesize antennas whose desirable properties approach the fundamental limits imposed by electromagnetics. As an additional benefit, the feedless optimization technique is shown to have greater computational efficiency than traditional antenna optimization techniques.

Download or read book Characteristic Modes written by Yikai Chen and published by John Wiley & Sons. This book was released on 2015-06-15 with total page 291 pages. Available in PDF, EPUB and Kindle. Book excerpt: Describes how to systematically implement various characteristic mode (CM) theories into designs of practical antenna systems This book examines both theoretical developments of characteristic modes (CMs) and practical developments of CM-based methodologies for a variety of critical antenna designs. The book is divided into six chapters. Chapter 1 provides an introduction and discusses the recent advances of the CM theory and its applications in antenna engineering. Chapter 2 describes the formulation of the characteristic mode theory for perfectly electrically conducting (PEC) bodies and discusses its numerical implementations. Chapter 3 presents the CM theory for PEC structures embedded in multilayered medium and its applications. Chapter 4 covers recent advances in CM theory for dielectric bodies and also their applications. Chapter 5 discusses the CM theory for N-port networks and its applications to the design of antenna arrays. Finally, Chapter 6 discusses the design of platform-integrated antenna systems using characteristic modes. This book features the following: Introduces characteristic mode theories for various electromagnetic structures including PEC bodies, structures in multilayered medium, dielectric bodies, and N-port networks Examines CM applications in electrically small antennas, microstrip patch antennas, dielectric resonator antennas, multiport antennas, antenna arrays, and platform mounted antenna systems Discusses numerical algorithms for the implementation of the characteristic mode theories in computer code Characteristic Modes: Theory and Applications in Antenna Engineering will help antenna researchers, engineers, and students find new solutions for their antenna design challenges.

Download or read book The Shape Synthesis of Non Planar and Closely Spaced Electrically Small Conducting Surface Antennas written by Anas Alakhras and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Antennas are needed in wireless communications of any kind and are key to the quality of any wireless link, irrespective of its use. There remains a need for electrically-small antennas that can fit on/in a restricted physical surface/volume for use in sensors (eg. Internet-of-Things) that need to "talk" to some data centre via the wireless network. The design issues associated with electrically-small antennas are well-known, and thus it will be appreciated that it would be advantageous to be able to design the above antennas in a way that exploits as much of the space allotted to them, as well the proximity of other objects present, to arrive at functioning antennas. Antennas of conventional shape do not necessarily do this. It might thus be best to perform a shape synthesis of an antenna that lets the electromagnetics decide on the shape of the final antenna in order to obtain the performance desired under the geometrical restrictions mentioned. Such shape synthesis has only been done for planar (2D) conducting surface antennas. In this thesis we develop the machinery for a computational electromagnetics-based tool capable of performing the shape synthesis of 3D conducting surface antennas for the first time. It has purposefully been developed in a way that allows it to capitalize on commercially available software for both the computational electromagnetics (CEM) and the genetic optimization algorithm (GA). A comprehensive 'shaping manager' software tool has been developed that controls the whole shaping process and communicates with the commercial software, in so doing implementing a desired shaping prescription. It is a complex tool whose development is based on a considerable amount of software engineering. The advantage of being able to utilize the commercial codes is that the work becomes accessible to others, such codes are more powerful and flexible than in-house codes, and they are also able to export files describing the complicated shaped geometries for fabrication. The shaping manager utilizes the characteristic mode concept so that one only needs to select the feed point once the shape synthesis has been completed. Fully 3D electrically-small conducting surface antenna examples are then successfully shape synthesized subject to various geometry restrictions. The validity of the modelling process is experimentally validated. The shape synthesis procedure is then extended to apply to the design of two closely-spaced electrically-small antennas operating at different frequencies, again with some experimental validation. Such shape synthesis has also not been done before. These procedures can be extended to the case where the two antennas in question are mounted on some electrically-large platform. However, if such platforms are electrically very large the full-wave computational burden may become prohibitive. We show that the characteristic modes for the antennas under shaping in such situations can in fact be found using hybrid method of moment / geometrical theory of diffraction (MM/GTD) methods, with only the antenna proper needing to be MM-meshed. An example is provided to demonstrate the computation of characteristic modes in this way. This possibility for characteristic mode computation has not yet been explicitly stated elsewhere (and so perhaps not realised), nor example computations provided. We believe this realisation might widen the scope of application of characteristic mode analysis.

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 THE SHAPE SYNTHESIS OF DIELECTRIC RESONATOR ANTENNAS FOR WIRELESS COMMUNICATION SYSTEMS written by Hamad Alroughani and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Antennas are needed in wireless communications of any kind and are key to the quality of any wireless link, irrespective of its use. The abilities needed of a particular antenna depend on its application, and so the cost of antennas in current use varies from a few cents for those in mobile devices, to many millions of dollars for the main mission antennas on satellites or sophisticated radar antennas in military use. They are indeed the eyes and ears of modern wireless communications systems. Dielectric resonator antennas are one of the popular antenna types and hold the promise of requiring less room for proper operation, in essence due to the loading effect of the material. The principal original contributions to antenna shape synthesis is presented in this dissertation; an approach is devised for the three-dimensional shape synthesis of dielectric resonator antennas which are subject to geometry restrictions. It is entirely new, representing the first time any three-dimensional shape optimization of dielectric resonator antennas has been described. It is particularly novel because, not only does it shape the dielectric material, but it permits the shape optimization process to proceed without the restriction of a pre-determined feed-point location. The approach is made possible through properly connecting antenna performance parameters to the use of characteristic mode concept which allows the computation of modal weighting coefficients using the surrogate source idea that is established. These coefficients are then used in the definition of the objective functions. The shape synthesis technique was successfully applied to three dielectric resonator antenna examples, each with different design requirements and constraints. Its success in these cases demonstrates the effectiveness of the new shaping technique. Computed performance is supported by experimental results. The implementation of the shaping tool itself, apart from being needed to validate the shaping process, is an addition in its own right. It has purposefully been fully implemented using commercially available software, for the computational electromagnetics, the optimization algorithm, and the controller that manages the shaping process and allows communication between the various steps. The advantage of being able to use such commercial codes is that the approach at once becomes more accessible to others. The determination of the characteristic modes of dielectric objects has been fraught with difficulties, and there have been uncertainties in the literature as to precisely what was being computed. A number of aspects of characteristic mode theory therefore had to be investigated and repaired before the shape synthesis work could proceed. Although they might not be linked directly to the shape synthesis process, other significant contributions are related to the characteristic mode analysis by developing a more robust method for tracking the characteristic modes of dielectric objects, presenting a more general (broadened) formulation of the sub-structure characteristic mode concept and providing formal mathematical proofs of the orthogonality properties of sub-structure modes.

Download or read book Antenna Pattern Synthesis written by Donald R. Rhodes and published by . This book was released on 1972 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: An investigation was made toward evolving a method of two-dimensional antenna pattern synthesis such that antenna specifications involving dimensionality, shape, and the constituent relations can be lated to the frequency characteristics. (Author).

Download or read book Design Methodology of Antennas Based on Metamaterials and the Theory of Characteristic Modes written by Mhamad Hassanein Rabah and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The rise of wireless communication systems and the big demand of high bit rate links have entailed researches to lie over new communications systems. With this diversity of wireless systems, flexibility for operating between different standards is strongly needed. Cognitive radio (CR) consist the future system that can offer this flexibility. The new features of CRs remains many challenges to their antennas. Miniaturization, isolation and bandwidth improvement, are all real needs and effective challenges. Especially when the geometry of the antenna become more complex in order to fit the terminal chassis. The use of metamaterials (MTM) has been introduced to overcome physics limitations in order to undertake these needs. The analysis of MTM in presence of radiating elements such antennas prove to be a challenge. In this thesis, an new approach to address these challenges is proposed. It is based on a modal concept using the theory of characteristic modes (TCM). It proves to be useful to analyse and design of electrically small antenna (ESA), metamaterial-inspired antennas and metamaterial-based antennas. Furthermore, the same approach is used to evaluate the antenna performances when surrounded by complex artificial materials by proposing closed formulas for the quality factor. This remains into a huge advantage in the antenna shape optimisation in the antenna industry. As a proof of concept, an extremely-wide-band antenna for underlay CR (sensing antenna) is developed using the proposed approach in order to have stable radiation pattern an high efficiency in the electrically small regime. An experimental validation of the performances of all the presented designs is also provided.

Download or read book Antenna Synthesis through the Characteristics of Desired Amplitude written by Mykhaylo I. Andriychuk and published by Cambridge Scholars Publishing. This book was released on 2019-09-12 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book is devoted to the synthesis problems that arise in the theory and design of radiating systems (antennas). The characteristics of desired amplitude are data placed into a synthesis problem. A synthesis problem belongs to a class of inverse problems and its aim is to determine a distribution of current or fields in an antenna, which produces the amplitude radiation characteristic as close as possible to the desired one. Freedom of choice of phase distribution of the desired radiation pattern (RP) is used as an additional possibility of better approximation to such RPs. This book studies various different types of antennas and arrays as the radiation systems under consideration. A special class of problems related to acoustic and electromagnetic scattering on a set of bodies (particles) of small size is also discussed, while the constructive procedures of creating inhomogeneous materials with specific properties are proposed.

Download or read book Synthesis Process Using Characteristic Modes for Multiple in Situ Antennas for System Radiation Requirements written by Nicole L. Bohannon and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Electromagnetic Fields written by Jean G. Van Bladel and published by John Wiley & Sons. This book was released on 2007-06-04 with total page 1188 pages. Available in PDF, EPUB and Kindle. Book excerpt: Professor Jean Van Bladel, an eminent researcher and educator in fundamental electromagnetic theory and its application in electrical engineering, has updated and expanded his definitive text and reference on electromagnetic fields to twice its original content. This new edition incorporates the latest methods, theory, formulations, and applications that relate to today's technologies. With an emphasis on basic principles and a focus on electromagnetic formulation and analysis, Electromagnetic Fields, Second Edition includes detailed discussions of electrostatic fields, potential theory, propagation in waveguides and unbounded space, scattering by obstacles, penetration through apertures, and field behavior at high and low frequencies.

Download or read book Novel Characteristic mode based Synthesis and Analysis Method for Reflectarray Antennas written by Abdul Maalik and published by . This book was released on 2020 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research will prove useful in the analysis and optimization of antenna arrays for the emerging 5G and satellite applications. CM-based analysis and optimization can prove good alternative to various brute-force optimization methods used in antenna array design.

Download or read book Numerical and Asymptotic Techniques in Electromagnetics written by F.J. Deadrick and published by Springer. This book was released on 1975-07-11 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modern Antenna Design written by Thomas A. Milligan and published by John Wiley & Sons. This book was released on 2005-07-11 with total page 646 pages. Available in PDF, EPUB and Kindle. Book excerpt: A practical book written for engineers who design and use antennas The author has many years of hands on experience designing antennas that were used in such applications as the Venus and Mars missions of NASA The book covers all important topics of modern antenna design for communications Numerical methods will be included but only as much as are needed for practical applications

Download or read book Antennas and Wave Propagation written by A. R. Harish and published by Oxford Higher Education. This book was released on 2007 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aimed at a single-semester course on antennas at the undergraduate level, Antennas and Wave Propagation provides a lucid explanation of the fundamentals of antennas and propagation. This student-friendly text also includes simple design procedures along with a large number of examples and exercises.

Download or read book International Aerospace Abstracts written by and published by . This book was released on 1998 with total page 980 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dielectric Resonator Antenna Handbook written by Aldo Petosa and published by Artech House Publishers. This book was released on 2007 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt: Today, more and more antenna engineers are viewing the Dielectric Resonator Antenna (DRA) as a preferable alternative to conventional low-gain designs because of several attractive features, including high radiation, light weight, small size and low profile. This practical resource presents complete, up-to-date details on DRAs in a single volume. The book provides professionals with clear guidance on the mode of operation and radiation behavior of DRAs, the main methods of excitation, and the major advances in DRA technology. This hands-on reference equips engineers with simple equations and graphs that help them rapidly design DRAs, without the need for complex analytical or numerical calculations. Numerous design examples are included to give practitioners a sense of the versatility that DRAs afford.

Download or read book Recent Microwave Technologies written by Ahmed Kishk and published by BoD – Books on Demand. This book was released on 2022-08-25 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microwave bands range from 300 MHz to 300 GHz of the electromagnetic spectrum. These signals can be used in communication, networking, astronomy, and biomedical engineering, among other fields. This book provides a comprehensive overview of the physics of microwave signals, techniques for modeling these signals, uses of these signals in various fields, and the underlying principles of some of the latest microwave devices currently available.