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Electromagnetic Time Reversal Electromagnetic Time Reversal Electromagnetic Time Reversal Electromagnetic Time Reversal Application to Electromagnetic Compatibility and Power Systems Edited by Farhad Rachidi Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland Marcos Rubinstein University of Applied Sciences of Western Switzerland, Yverdon, Switzerland Mario Paolone Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland This edition first published 2017 © 2017 John Wiley & Sons, Ltd All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by law. Advice on how to obtain permission to reuse material from this title is available at http://www.wiley.com/go/permissions. The right of Farhad Rachidi, Marcos Rubinstein, and Mario Paolone to be identified asthe authors of the editorial material in this work has been asserted in accordance with law. Registered Offices John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, USA John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, UK Editorial Office The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, UK For details of our global editorial offices, customer services, and more information about Wiley products visit us at www.wiley.com. Wiley also publishes its books in a variety of electronic formats and by print-on-demand. Some content that appears in standard print versions of this book may not be available in other formats. Limit of Liability/Disclaimer of Warranty The publisher and the authors make no representations or warranties with respect tothe accuracy or completeness of the contents of this work and specifically disclaim all warranties, including without limitation any implied warranties of fitness for a particular purpose. This work is sold with the understanding that the publisher is not engaged in rendering professional services. The advice and strategies contained herein may not be suitable forevery situation. In view of ongoing research, equipment modifications, changes in governmental regulations, and the constant flow of information relating to the use of experimental reagents, equipment, and devices, the reader is urged to review and evaluate the information provided in the package insert or instructions for each chemical, piece of equipment, reagent, or device for, among other things, any changes in the instructions or indication of usage and for added warnings and precautions. The fact that an organization or website is referred to in this work as a citation and/or potential source of further information does not mean that the author or the publisher endorses the information the organization or website may provide or recommendations it may make. Further, readers should be aware that websites listed in this work may have changed or disappeared between when this works was written and when it is read. No warranty may be created or extended by any promotional statements for this work. Neither the publisher nor the author shall be liable for any damages arising herefrom. Library of Congress Cataloging-in-Publication Data Names: Rachidi, Farhad, 1962– editor. | Rubinstein, Marcos, 1960– editor. | Paolone, Mario, 1973– editor. Title: Electromagnetic time reversal : application to electromagnetic compatibility and power systems / edited by, Farhad Rachidi, Marcos Rubinstein, Mario Paolone. Description: Hoboken, New Jersey : John Wiley & Sons, Inc., [2017] | Includes bibliographical references and index. Identifiers: LCCN 2016042856 (print) | LCCN 2016052640 (ebook) | ISBN 9781119142089 (cloth ; alk. paper) | ISBN 1119142083 (cloth ; alk. paper) | ISBN 9781119142096 (Adobe PDF) | ISBN 9781119142102 (ePub) Subjects: LCSH: Time reversal. | Electromagnetism. | Electromagnetic compatibility. | Electric power systems. Classification: LCC QC173.59.T53 E44 2017 (print) | LCC QC173.59.T53 (ebook) | DDC 621.3101/53–dc23 LC record available at https://lccn.loc.gov/2016042856 Cover image: Kaisorn/Gettyimages Sylverarts/Gettyimages Set in 10/12pt WarnockPro by Aptara Inc., New Delhi, India 10987654321 “Lost time is never found again” Benjamin Franklin vii Contents List of Contributors ix Preface xi About the Companion Website xvii Time Reversal: A Different Perspective 1 M. Rubinstein, F. Rachidi, and M. Paolone Time Reversal in Diffusive Media 29 A. Cozza and F. Monsef From Electromagnetic Time-Reversal Theoretical Accuracy to Practical Robustness for EMC Applications 91 P.Bonnet,S.Lallech´ ere,` and F. Paladian Amplification of Electromagnetic Waves Using Time Reversal 145 Matthieu Davy, Mathias Fink, and Julien de Rosny Application of Time Reversal to Power Line Communications for the Mitigation of Electromagnetic Radiation 169 P.Pagani,M.Ney,andA.Zeddam Application of Electromagnetic Time Reversal to Lightning Location 189 M. Rubinstein and F. Rachidi viii Contents Electromagnetic Time Reversal Applied to Fault Location in Power Networks 217 R. Razzaghi, G. Lugrin, M. Paolone, and F. Rachidi Index 275 ix ListofContributors Pierre Bonnet Pascal Paganini Blaise Pascal University Telecom Bretagne Andrea Cozza Franc¸oise Paladian Group of Electrical Blaise Pascal University Engineering Paris (GeePs) Mario Paolone Matthieu Davy Swiss Federal Institute of University of Rennes Technology of Lausanne Julien de Rosny (EPFL) Langevin Institute Farhad Rachidi Mathias Fink Swiss Federal Institute of Langevin Institute Technology of Lausanne (EPFL) Sebastien´ Lallech´ ere` Blaise Pascal University Reza Razzaghi Gaspard Lugrin Swiss Federal Institute of Swiss Federal Institute of Technology of Lausanne Technology of Lausanne (EPFL) (EPFL) Marcos Rubinstein Florian Monsef University of Applied Group of electrical Sciences of Western engineering Paris (GeePs) Switzerland Michel Ney Ahmed Zeddam Telecom Bretagne Orange Labs xi Preface Time reversal has emerged as a very interesting technique with potential applications in various fields of engineering. It has received a great deal of attention in recent years, essentially in the field of acoustics, where it was first developed by Prof. Fink and his team in the 1990s. In the past decade, the technique has also been used in the field of electromagnetics and applied to various other areas of electrical engineering. In particular, the technique has been successfully applied in the fields of elec- tromagnetic compatibility (EMC) and power systems, leading to mature technologies in source-location identification with unprecedented performance compared to classical approaches. It is expected that the fields of application of electromag- netic time reversal (EMTR) will continue to grow in the near future. This book is intended to give the theoretical foundation of the electromagnetic time-reversal theory. Special emphasis is given on real applications in the fields of EMC and power systems. The book’s introductory chapter presents the theoretical basis of the electromagnetic time-reversal technique. It starts with a discussion of the notion of time in physics and goes on to present three approaches that can be used to effectively make a system go back in time, in the sense that it retraces the path it came from in the immediate past. The concepts of strict and soft time-reversal invariance are introduced and illustrated using simple examples. The time-reversal invariance of physics laws is then described, with special attention given to the time-reversal invariance of Maxwell’s equations. The concept of time-reversal cavity and the use of time reversal as a means of refocusing electromagnetic xii Preface waves is then described. The chapter ends with a brief presenta- tion of application areas of electromagnetic time reversal. Chapters 2 to 7 are devoted to specific applications of EMTR, including EMC measurements, EM field focusing and amplifi- cation, interference mitigation in power line communications, lightning detection, and fault location in power systems. In Chapter 2, the potential use of time reversal in diffusive media for radiative testing is addressed, in particular for EMC, antenna testing, and channel emulation. The chapter starts with a brief review of common features of diffusive media, introducing probabilistic models for the random nature of fields in them, showing the complexity of the media and making the case for the generation of coherent wavefronts. The response of a diffusive medium to time-reversed signals is then analyzed for point-to-point transmissions, illustrating how received signals are affected by background random fluctuations due to the frequency-selective response of the medium. It is shown that narrow bandwidths are sufficient to enable the properties of time reversal, a point that is of fundamental importance in high-power microwave applications. Other properties are then presented, including the possibility of using single-antenna time-reversal (TR) mirrors and the ability of TR to control the polarization of received fields, independent of the features of the transmitting antenna. In addition, spatial and time focusing are shown to lead to energy efficiencies even higher than those expected in reverberation chambers. Virtual sources are introduced based on the observation that standard TR assumes the availability of sources of radiation whose fields will then be time-reversed. In the final part of the chapter, a generalization of TR is presented that allows the generation of complex, arbitrary wavefronts. Chapter 3 deals with the robustness of the EMTR process for
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