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Springer Aerospace Technology Amur B. Khashimov Rinat R. Salikhov Practical Models of Antenna Systems Springer Aerospace Technology Series Editors Sergio De Rosa, DII, University of Naples Federico II, Napoli, Italy Yao Zheng, School of Aeronautics and Astronautics, Zhejiang University, Hangzhou, Zhejiang, China Elena Popova, AirNavigation Bridge Russia, Chelyabinsk, Russia The series explores the technology and the science related to the aircraft and spacecraft including concept, design, assembly, control and maintenance. The topics cover aircraft, missiles, space vehicles, aircraft engines and propulsion units. The volumes of the series present the fundamentals, the applications and the advances in all the fields related to aerospace engineering, including: ● structural analysis, ● aerodynamics, ● aeroelasticity, ● aeroacoustics, ● flight mechanics and dynamics ● orbital maneuvers, ● avionics, ● systems design, ● materials technology, ● launch technology, ● payload and satellite technology, ● space industry, medicine and biology. The series’ scope includes monographs, professional books, advanced textbooks, as well as selected contributions from specialized conferences and workshops. The volumes of the series are single-blind peer-reviewed. To submit a proposal or request further information, please contact: Mr. Pierpaolo Riva at [email protected] (Europe and Americas) Mr. Mengchu Huang at [email protected] (China) The series is indexed in Scopus and Compendex · Amur B. Khashimov Rinat R. Salikhov Practical Models of Antenna Systems Amur B. Khashimov Rinat R. Salikhov Department of Design and Manufacture NPO RTS LLC of Radio Equipment Chelyabinsk, Russia School of Electronic Engineering and Computer Science South Ural State University (National Research University) Chelyabinsk, Russia ISSN 1869-1730 ISSN 1869-1749 (electronic) Springer Aerospace Technology ISBN 978-981-19-6218-9 ISBN 978-981-19-6219-6 (eBook) https://doi.org/10.1007/978-981-19-6219-6 © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022 This work is subject to copyright. All rights are solely and exclusively licensed by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Singapore Pte Ltd. The registered company address is: 152 Beach Road, #21-01/04 Gateway East, Singapore 189721, Singapore Introduction Mathematical modeling occupies an important place in the design of antenna systems. This is due to a significant complication of the structure of antenna systems and their functional characteristics, primarily for phased antenna arrays, where the issues of mutual influence of radiators should be considered both for a given frequency band and in the scanning sector, taking into account polarization characteristics. This leads to the need to use mathematical models of real radiators of antenna systems, built on the basis of strict electrodynamic relationships and taking into account the installation object. In this case, the developers of antenna systems have the possibility of a detailed analysis of the electromagnetic radiation field of antenna systems and the synthesis of corrective functions of the amplitude-phase distribution to compensate for the influence Particular attention in the practice of mathematical modeling of complex antenna systems is given to the reliability of the results obtained. Therefore, the main results presented in the book have undergone a detailed verification by solving test problems that admit a rigorous analytical solution. At the same time, it should be noted that such solutions are most often represented as infinite Fourier series in special functions, the calculation of which, in turn, is associated with certain errors. Consequently, a slight discrepancy between the results of analytical and numerical results of the study of mathematical models is often associated not only with the approximation and discretization of a real electrodynamic problem but also with approximations of finite series, especially in the field of asymptotic estimates of special functions. Therefore, a high degree of agreement between numerical results and analytical solu- tions indicates the reliability of mathematical models and the possibility of their use in the design of antenna systems. In the absence of rigorous analytical solutions to the corresponding boundary value problems, one of the ways to verify the results obtained is an experimental study of the developed antenna system. It is impor- tant that antenna measurements have their own specific features, but the qualitative agreement of the results is also a criterion for the adequacy of mathematical models. It should also be noted here that numerous variants of antenna systems developed using the mathematical models proposed by the authors have received appropriate experimental confirmation. v vi Introduction The materials of the book may be useful to developers of antenna systems and students of radio engineering specialties. In Chap. 1, questions of the asymptotic correspondence of two-dimensional and three-dimensional problems of antenna technology are considered. It is shown that, for solving many practical problems, the establishment of such a correspondence leads to the possibility of a significant simplification of the mathematical modeling of complex antenna systems installed near various scattering objects. The formulation of mathematical models in the form of integral equations and the use of effective numerical methods for solving them makes it possible to obtain a large number of results that can be used as estimates of the parameters of the designed antenna systems. Chapter 2 presents a technique for the formation of mathematical models of dipole antennas of vertical polarization, installed near extended cylindrical objects (metal, dielectric, combined). It is shown that the asymptotic correspondence of two- dimensional and three-dimensional electrodynamic problems, described in Chap. 1, leads to the possibility of calculating the radiation field of such antenna systems in the far zone using effective mathematical models in a scalar formulation. The legit- imacy of the transition from vector problems to much simpler scalar problems has been proved by computational experiments. Chapter 3 considers the problems of practical application of methods for correcting the synthesized excitation of an antenna system, when the actual operating conditions suggest the possible influence of various scattering objects. As a rule, the influence of such objects leads to the formulation of incorrect problems, since the specified requirements for correction lead to unrealizable excitation functions. It is shown that the variational formulation of the correction problem leads to the possibility of using methods for minimizing variational functionals and the iterative regularization method. Computational experiments show high efficiency of iterative regularization in the presence of random errors in the input data. In Chap. 4, statistical modeling of the accuracy of the functioning of the localizer antenna system of the radio navigation system was carried out. The need for such a study is due to the multifactorial influence of various random errors that occur in the dividers and cable paths of the emitters, and the instability of the transmitter frequency. The obtained statistical estimates of accuracy can be used in the design of antenna systems and in the practice of operating radio navigation systems. Chapter 5 discusses the practical application of orthogonal bases for the decom- position of polarization vectors for the synthesis of excitation of a promising radio navigation system VDB (Very High Frequency Data Broadcast). The application of methods for optimizing the residual functional of the solution in the frequency band leads to the possibility of constructing an antenna system that meets the specified requirements for both the directional properties and the polarization characteristics of the radiation field. Experimental studies confirm the reliability of the adopted design solutions. Chapter 6 provides a consistent method for forming a mathematical model of a DME (Distance Measuring Equipment) antenna system. The use of integral equations of the second kind provides a stable numerical solution for thin metal reflectors Introduction vii using special quadrature formulas. To optimize the shape of the reflector, a nonlinear function is used, the minimization of which leads to acceptable characteristics of the radiation field. An example of the practical use of the developed mathematical model for designing an antenna system is given, the simulation results are confirmed by experimental studies in the coverage area of the antenna system. In Chap. 7, based on the asymptotic correspondence of two-dimensional and three-dimensional problems, using a rigorous electrodynamic approach, methods for solving the ill-posed problem of reconstructing the radiation field from the results of measurements in the near field are considered. This assumes the presence of statistical measurement errors that affect the accuracy of the reconstruction. The mathematical reconstruction model takes into account the influence of nearby scattering objects. A series of computational experiments were carried out using iterative regularization of an ill-posed reconstruction problem. At the end of the book is a bibliographic list, which does not claim to be complete. All calculations were carried out on the basis of the supercomputing center of the South Ural State University (National Research University, http://supercomputer. susu.ac.ru. South Ural State University (National Research University). Amur B. Khashimov Rinat R. Salikhov Gratitude The authors of the book express their deep gratitude for many years of coopera- tion and work on joint projects: Candidate of Technical Sciences M.S. Vorobyov, Associate Professor of the Department of Infocommunication Technologies, South Ural State University, and Candidate of Technical Sciences L. P. Kudrin, Associate Professor of the Department of Design and Production of Radio Equipment, South Ural State University. Thanks to the participation of colleagues, a number of results were obtained, which are reflected in the book. The authors will always remember with warmth and gratitude: A. I. Gromov, senior engineer, leading specialist in antenna arrays of the USSR and the Russian Federation; G. N. Pirogov, chief designer of the air navigation and landing system of civil aviation of the USSR and the Russian Federation; A. M. Baidikov, a specialist in air navigation systems, a participant in the Buran project. The authors of the book are grateful for many years of communication, advice, support to the staff of the Institute of Radio Electronics and Information Technology- RTF of the Federal State Autonomous Educational Institution of Higher Education “Ural Federal University named after the first President of Russia B. N. Yeltsin”: Doctor of Technical Sciences B. A. Panchenko, Professor of the Depart- ment of High-Frequency Radio Communications and Television, Doctor of Tech- nical Sciences S. T. Knyazev, Professor of the Department of Radioelectronics and Telecommunications, Vice-Rector for Academic Affairs; Doctor of Tech- nical Sciences S. N. Shabunin, Associate Professor, Head of the Department of Radioelectronics and Telecommunications. Separately, the authors note the contribution to the creation of the book and thank E. G. Popova, Head of the project to popularise Russian aviation science and tech- nology abroad. Thanks to her motivation, dedication, perseverance, this book was written. The authors are grateful to the translator of the book A. V. Kudryashova. The authors thank their family and friends for the opportunity to devote enough time to writing the book. The authors are grateful and thankful to their employers: ix x Gratitude Federal State Autonomous Educational Institution of Higher Education “South Ural State University (National Research University)” “SUSU (NIU)”; www.susu.ru NPO “RTS” LLC, www.nports.ru.

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