Download or read book Antenna Arrays Performance Limits and Geometry Optimization written by consultant expert mohamed taha and published by . This book was released on 2021-02-02 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACTThe radiation pattern of an antenna array depends strongly on the weighting methodand the geometry of the array. Selection of the weights has received extensive attention,primarily because the radiation pattern is a linear function of the weights. However, thearray geometry has received relatively little attention even though it also stronglyinfluences the radiation pattern. The reason for this is primarily due to the complex wayin which the geometry affects the radiation pattern. The main goal of this dissertation isto determine methods of optimizing array geometries in antenna arrays.An adaptive array with the goal of suppressing interference is investigated. It isshown that the interference rejection capabilities of the antenna array depend upon itsgeometry. The concept of an interference environment is introduced, which enablesoptimization of an adaptive array based on the expected directions and power of theinterference. This enables the optimization to perform superior on average, instead of forspecific situations. An optimization problem is derived whose solution yields an optimalarray for suppressing interference. Optimal planar arrays are presented for varyingnumber of elements. It is shown that, on average, the optimal arrays increase the signalto-interference-plus-noise ratio (SINR) when compared to standard arrays.Sidelobe level is an important metric used in antenna arrays, and depends on theweights and positions in the array. A method of determining optimal sidelobeminimizing weights is derived that holds for any linear array geometry, beamwidth,antenna type and scan angle. The positions are then optimized simultaneously with theoptimal weights to determine the minimum possible sidelobe level in linear arrays. Results are presented for arrays of varying size, with different antenna elements, and fordistinct beamwidths and scan angles.Minimizing sidelobes is then considered for 2D arrays. A method of determiningoptimal weights in symmetric 2D arrays is derived for narrowband and wideband cases.The positions are again simultaneously optimized with the weights to determine optimalarrays, weights and sidelobe levels. This is done for arrays with varying number ofelements, beamwidths, bandwidths, and different antenna elements.

Download or read book Antenna Arrays written by Peter Joseph Bevelacqua and published by . This book was released on 2008 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Array Pattern Optimization written by Jafar Ramadhan Mohammed and published by BoD – Books on Demand. This book was released on 2019-03-27 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: Array pattern optimization is a very important and necessary issue in the majority of modern communication systems in a variety of applications such as sonar, radar, navigation, wireless communications, and many other engineering fields. Classical methods for array pattern synthesis have worked mainly with analytical models that are linear, local and, thus, their performances were not optimum. They have always been designed with closed-form mathematical models. Unlike these analytical methods, the global optimization methods with powerful computing tools offer optimum solutions. During the last few years, the design of the antenna arrays has been a topic of significant research activity. This book presents recent advances in the field of array pattern optimization. It is targeted primarily toward students and researchers who want to be exposed to a wide variety of antenna array design and optimization. It includes five chapters as well as the introductory chapter. These five chapters are categorized into five different areas depending on the application. These applications are ordered to address interference suppression, electronic toll collection, mmWave and ultra-wideband, integrated antennas, and educational packages for modeling smart antenna for 5G wireless communications. The book has the advantage of providing a collection of applications that are entirely independent and self-contained; thus, the interested reader can choose any chapter and skip to another without losing continuity.

Download or read book Simulation based Optimization Of Antenna Arrays written by Slawomir Koziel and published by World Scientific. This book was released on 2019-02-13 with total page 494 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book addresses surrogate-assisted design of antenna arrays, in particular, how surrogate models, both data-driven and physics-based, can be utilized to expedite procedures such as parametric optimization, design closure, statistical analysis, or fault detection. Algorithms and design frameworks are illustrated using a large variety of examples including real-world printed-circuit antenna and antenna array structures.This unique compendium contains introductory materials concerning numerical optimization, both conventional (gradient-based and derivative-free, including metaheuristics) and surrogate-based, as well as a considerable selection of customized procedures developed specifically to handle antenna array problems. Recommendations concerning practical aspects of surrogate-assisted multi-objective antenna optimization are also given. The methods presented allow for cost-efficient handling of antenna array design problems (involving CPU-intensive EM models) in the context of design optimization and statistical analysis, which will benefit both researchers, designers and graduate students.

Download or read book Advances in Array Optimization written by Ertugrul Aksoy and published by BoD – Books on Demand. This book was released on 2020-03-04 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: The need to develop technology and communication necessitates the design of flexible and high-capacity radiating systems in today's communication infrastructure. In this context, antenna arrays are the ideal solution and have been one of the priority research subjects of the science community dealing with electromagnetics from past to present. Optimization of an array may be performed in various ways such as the optimization of excitation, reflector structure, feed network, etc. depending on the array structure. This book is a collection of seven research studies focused on the optimization of array structures in classical phased array or time modulation, including radiator, reflector, feed network, and radiating element optimizations.

Download or read book Analysis and Optimisation of Array Antennas for Near field Plane Wave Synthesis written by Neil Norman Jackson and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Radiated electromagnetic compatibility (EMC) testing requires field distributions of uniform intensity throughout a test zone. This field condition is achieved within a plane wave. The use of the reflector-fed compact range for generating plane waves is well established for antenna measurements in the microwave frequency region. Extension of this technique into the sub-microwave range poses problems and this work investigates the applicability of antenna arrays for such tests. The basic problem is to determine suitable array element excitations in order to generate an approximate plane wave in the antenna near-field. Some general numerical synthesis techniques are described and shown to be applicable to arrays of arbitrary element composition and geometry. For concept verification, a prototype array of log-periodic dipole antennas was constructed and its performance accurately predicted using a computer model. Factors affecting the plane wave quality are discussed and adequate performance for some types of antenna measurements as well as for EMC testing is illustrated. One important factor influencing the plane wave quality is the geometrical arrangement of the array elements. A novel procedure for optimising the array element locations using a genetic algorithm is presented. Practical array design issues are addressed and the development of a computer-controlled wide-band feed network is presented. As an exercise in application of the array-illuminated compact range, its use to irradiate a sphere simulating the human head is discussed. Measurements of the field distribution were used to validate a finite-difference time-domain computer model of the system.

Download or read book Innovations in Satellite Communications and Satellite Technology written by Daniel Minoli and published by John Wiley & Sons. This book was released on 2015-02-20 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surveys key advances in commercial satellite communications and what might be the implications and/or opportunities for end-users and service providers in utilizing the latest fast-evolving innovations in this field This book explores the evolving technical options and opportunities of satellite networks. Designed to be a self-contained reference, the book includes background technical material in an introductory chapter that will serve as a primer to satellite communications. The text discusses advances in modulation techniques, such as DBV-S2 extensions (DVS-S2X); spotbeam-based geosynchronous and medium earth orbit High Throughput Satellite (HTS) technologies and Internet applications; enhanced mobility services with aeronautical and maritime applications; Machine to Machine (M2M) satellite applications; emerging ultra HD technologies; and electric propulsion. The author surveys the latest innovations and service strategies and the resulting implications, which involves: Discussing advances in modulation techniques and HTS spotbeam technologies Surveying emerging high speed aeronautical mobility services and maritime and other terrestrial mobility services Assessing M2M (machine-to-machine) applications, emerging Ultra HD video technologies and new space technology Satellite communication is an integral part of the larger fields of commercial, television/media, government, and military communications, because of its multicast/broadcast capabilities, mobility, reliability, and global reach. High Throughput Satellites) are expected to revolutionize the field during this decade, providing very high speed, yet cost-effective, Internet access and connectivity anywhere in the world, in rural areas, in the air, and at sea. M2M connectivity, enabled by satellite communications, connects trucks on transcontinental trips, aircraft in real-time-telemetry aggregation, and mercantile ships. A comprehensive analysis of the new advances in satellite communications, Innovations in Satellite Communications Technology is a reference for telecommunications and satellite providers and end-users, technology investors, logistic professionals, and more.

Download or read book Optimization of Performance Indices in Discrete Array Systems written by David Keun Cheng and published by . This book was released on 1967 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: A basic theorem useful for the optimization of the performance indices of arbitrary antenna arrays is first reviewed. It is then applied to a general, three-dimensional array. In particular, it is specialized to determine the maximum obtainable directive gain and the main-beam radiation efficiency for circular and elliptical arrays. The gain optimization principle is also extended to arrays responding to quasi-monochromatic periodic signals and to arrays which are subject to random errors in excitation amplitudes and phases and in element positions. When the performance index of interest is the output signal-to-noise power ratio, consideration must be given to the power spectral densities of both the signal and the noise, the noise spatial distribution, the antenna space-frequency response function, the system internal noise, and the transfer function of the linear processor. The procedure for the maximization of the output signal-to-noise power ratio of an array of an arbitrary geometrical configuration when there are random variations in the design parameters is also reviewed. (Author).

Download or read book Optimization of Antenna Arrays by Simulated Annealing written by Víctor Jaime De la Rosa Pérez and published by . This book was released on 2005 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Deployable Reflector Antenna Performance Optimization Using Automated Surface Correction and Array feed Compensation written by Lyle C. Schroeder and published by . This book was released on 1992 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Introduction to Adaptive Arrays written by Robert A. Monzingo and published by SciTech Publishing. This book was released on 2004 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introduction to Adaptive Arrays serves as an introduction to the subject of adaptive sensor systems whose principle purpose is to enhance the detection and reception of certain desired signals. The field of array sensor systems is now a maturing technology. With applications of these systems growing more and more numerous, there is a wealth of widely scattered literature on various aspects of such systems. Unfortunately, few books attempt to provide an integrated treatment of the entire system that gives the reader the perspective to organize the available literature into easily understood parts. Intended for use both as a graduate level textbook and as a reference work for engineers, scientists, and systems analysts, this book provides such an integrated treatment by emphasizing the principles and techniques that are of fundamental importance in modern adaptive array systems.

Download or read book The World of Applied Electromagnetics written by Akhlesh Lakhtakia and published by Springer. This book was released on 2017-08-08 with total page 735 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book commemorates four decades of research by Professor Magdy F. Iskander (Life Fellow IEEE) on materials and devices for the radiation, propagation, scattering, and applications of electromagnetic waves, chiefly in the MHz-THz frequency range as well on electromagnetics education. This synopsis of applied electromagnetics, stemming from the life and times of just one person, is meant to inspire junior researchers and reinvigorate mid-level researchers in the electromagnetics community. The authors of this book are internationally known researchers, including 14 IEEE fellows, who highlight interesting research and new directions in theoretical, experimental, and applied electromagnetics.

Download or read book Wireless Network Performance Enhancement via Directional Antennas Models Protocols and Systems written by John D. Matyjas and published by CRC Press. This book was released on 2015-11-18 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: Directional antenna technologies have made significant advancements in the last decade. These advances have opened the door to many exciting new design opportunities for wireless networks to enhance quality of service (QoS), performance, and network capacity. In this book, experts from around the world present the latest research and development in

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 716 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Optimization and Synthesis of Antenna Arrays written by Samuel L. Shih and published by . This book was released on 1966 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt: New methods are developed for the optimization and synthesis of antenna arrays. The first part deals with the problem of optimizing the performance of an array in terms of gain, supergain ratio, and sidelobe. For the optimization of the gain, it is proposed to adjust both the excitation and the spacing of the elements. The determination of the optimum excitation, spacing and gain is shown to be an eigenvalue problem and is carried out on a digital computer using the difference calculus and the Newton-Raphson method. For the minimization of the supergain ratio, it is shown that this can also be reduced to an eigenvalue problem. For the reduction of the sidelobes, a new method is developed by which the phase shifts of the elements required for the minimum sidelobe level are determined in one step. In the synthesis part, orthogonal functions including the sinc function, ultraspherical polynomials, Chebyshev polynomials and Legendre polynomials are used to synthesize an array to radiate a prescribed pattern. Another new synthesis method is developed using the Lambda function which is not an orthogonal set. The synthesized array approximates the prescribed pattern with a high degree of precision. Finally, the equivalence between linear and planar arrays is established which enables the extension of the previous work to two-dimensional arrays, in particular, the planar arrays with shaped contour. (Author).

Download or read book Ultrawideband Radar written by James D. Taylor and published by CRC Press. This book was released on 2017-12-19 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: Providing a practical review of the latest technology in the field, Ultrawideband Radar Applications and Design presents cutting-edge advances in theory, design, and practical applications of ultrawideband (UWB) radar. This book features contributions from an international team of experts to help readers learn about a wide range of UWB topics, including: History of the technology American and European governmental regulations and key definitions Nonsinusoidal wave propagation theory Random signal radar Object detection by ground permittivity measurements Large-target backscattering effects Medical applications Large current radiator antenna design Materials-penetrating theory Radar signal processing Weak-signal detection methods Holographic and real time radar imaging This book’s contributors use practical information to illustrate the latest theoretical developments and demonstrate UWB radar principles through case studies. Radar system engineers will find ideas for precision electronic sensing systems for use in medical, security, industrial, construction, and geophysical applications, as well as those used in archeological, forensic and transportation operations.

Download or read book Empirical Optimization of Antenna Arrays written by S. Blank and published by . This book was released on 1971 with total page 71 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report describes a technique developed to optimize the performance of antenna arrays under realistic, on the vehicle conditions. This technique permits free choice of optimality criteria and design parameters and is applicable to both planar and nonplanar arrays with geometric constraints. The need for an improved Airborne Early Warning (AEW) airplane, the improvement being that of an airborne antenna system with reduced side lobes, was the main impetus for this investigation. The work reported grew from an initial study of the antenna array problem under the assumption of idealized free-space conditions. An experimental-computational approach to the solution of this problem has been formulated in which powerful n-dimensional optimum search methods (i.e., the Davidon algorithm) are applied to experimental data obtained from carefully scaled models of the vehicle and antenna array configuration. The optimization algorithm provides a new design for the antenna array that is then used in the scale model, and the process develops in an iterative fashion. The necessary laboratory setup and data processing techniques used to test the feasibility of this approach are discussed. Experimental results showing encouraging improvements have been obtained on an array of eight elements both with and without an aircraft model. These results indicate that the algorithmic procedure is both stable and convergent. (Author).