Dielectric Resonator Antennas

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Dielectric Resonator Antennas ELECTRONIC & ELECTRICAL ENGINEERING RESEARCH STUDIES ANTENNAS SERIES Series Editor: Professor J. R. James The Royal Military College of Science (Cranfield University), Shrivenham, Wiltshire,UK 10. Frequency Selective Surfaces: Analysis and Design J. C. Vardaxoglou 11. Dielectric Resonator Antennas Edited by K. M. Luk and K. W. Leung 12. Antennas for Information Super-Skyways P. S. Neelakanta and R. Chatterjee Dielectric Resonator Antennas Edited By K. M. Luk and K. W. Leung Both of the City University of Hong Kong RESEARCH STUDIES PRESS LTD. Baldock, Hertfordshire, England RESEARCH STUDIES PRESS LTD. 16 Coach House Cloisters, 10 Hitchin Street, Baldock, Hertfordshire, SG7 6AE, England www.research-studies-press.co.uk and Institute of Physics PUBLISHING, Suite 929, The Public Ledger Building, 150 South Independence Mall West, Philadelphia, PA 19106, USA Copyright 2003, by Research Studies Press Ltd. Research Studies Press Ltd. is a partner imprint with the Institute of Physics PUBLISHING All rights reserved. No part of this book may be reproduced by any means, nor transmitted, nor translated into a machine language without the written permission of the publisher. Marketing: Institute of Physics PUBLISHING, Dirac House, Temple Back, Bristol, BS1 6BE, England www.bookmarkphysics.iop.org Distribution: NORTH AMERICA AIDC, 50 Winter Sport Lane, PO Box 20, Williston, VT 05495-0020, USA Tel: 1-800 632 0880 or outside USA 1-802 862 0095, Fax: 802 864 7626, E-mail: orders@aidcvt.com UK AND THE REST OF WORLD Marston Book Services Ltd, P.O. Box 269, Abingdon, Oxfordshire, OX14 4YN, England Tel: + 44 (0)1235 465500 Fax: + 44 (0)1235 465555 E-mail: direct.order@marston.co.uk Library of Congress Cataloguing-in-Publication Data Dielectric resonator antennas / edited by K.M. Luk and K.W. Leung. p. cm. Includes bibliographical references and index. ISBN 0-86380-263-X 1. Microwave antennas. 2. Dielectric resonators. I. Luk, K. M. (Kwai Man), 1958- II. Leung, K. W. (Kwok Wa), 1967 - TK7871.67.M53 D54 2002 621.384' 135--dc21 2002069684 British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library. ISBN 0 86380 263 X Printed in Great Britain by SRP Ltd., Exeter Cover artwork by A3 grafix ltd. v Editorial Foreword There is now a massive research literature on the Dielectric Resonator Antenna (DRA) giving ample evidence that the topic has reached an age of maturity. This new book is therefore very timely and fills a gap in the literature. In fact the absence of any such reference book to date, that collates research findings and significant achievements, is somewhat surprising in view of the growing interest in DRAs. Like microstrip antennas, DRAs offer many degrees of design freedom and exploit the properties of innovative materials that make possible the manufacture of stable low cost products. Again, like microstrip antennas, DRAs evolved from components in shielded microwave circuits where radiation is an unwanted by-product. Making use of the latter to create the DRA illustrates once again the ingenuity of antenna designers. The reader will find the book coverage both wide and deep, with copious details of how to analyse and efficiently compute numerous DRA shapes and feeding arrangements. Engineering design data on extending the bandwidth and controlling the radiation pattern characteristics are focussed on throughout and specific chapters address DRA arrays and leaky-wave derivatives. When I visited the City University of Hong Kong in 1999 I was most impressed with Professor Luks research leadership and the dynamic environment in which he is working. Without doubt the enthusiasm of Kwai Man Luk and Kwok Wa Leung has energised both the writing of this book and their team of distinguished authors, many of whom, if not most, have made foremost contributions to this field of research. The book will have widespread appeal to postgraduate researchers, antenna design engineers in general and particularly those engaged in the innovative design of mobile and wireless/Bluetooth systems. May I congratulate Professor Luk and Dr Leung and their co-authors on the production of this significant text, which will be a milestone in the advancement of the DRA concept and of great benefit to the international antenna community. Professor Jim R James April 2003 vi Preface The field of wireless communications has been undergoing a revolutionary growth in the last decade. This is attributed to the invention of portable mobile phones some 15 years ago. The success of the second-generation (2G) cellular communication services motivates the development of wideband third-generation (3G) cellular phones and other wireless products and services, including wireless local area networks, home RF, Bluetooth, wireless local loops, local multi-point distributed networks (LMDS), to name a few. The crucial component of a wireless network or device is the antenna. Very soon, our cities will be flooded with antennas of different kinds and shapes. On the other hand, for safety and portability reasons, low power, multi-functional and multi-band wireless devices are highly preferable. All these stringent requirements demand the development of highly efficient, low-profile and small-size antennas that can be made imbedded into wireless products. In the last 2 decades, two classes of novel antennas have been investigated and extensively reported on. They are the microstrip patch antenna and the dielectric resonator antenna. Both are highly suitable for the development of modern wireless communications. The use of a dielectric resonator as a resonant antenna was proposed by Professor S. A. Long in the early nineteen eighties. Since the dielectric resonator antenna has negligible metallic loss, it is highly efficient when operated at millimetre wave frequencies. Conversely, a high-permittivity or partially-metallised dielectric resonator can be used as a small and low-profile antenna operated at lower microwave frequencies. Low loss dielectric materials are now easily available commercially at very low cost. This would attract more system engineers to choose dielectric resonator antennas when designing their wireless products. Although dielectric resonator antennas are so promising in practical applications, surprisingly, no edited books or reference books summarising the research results on dielectric resonator antennas are available in the literature. Actually, hundreds of articles on the design and analysis of dielectric resonator antennas can be found in reputable international journals or in major international conference proceedings. It is the objective of this edited book to update and to present new information on dielectric resonator antennas. We have been very fortunate to receive contributions from most of the distinguished scholars working in this exciting area. The book is intended to serve as a compendium of essential viiprinciples, design guidelines and references for practicing engineers, research engineers, graduate students and professors specialising in the areas of antennas and RF systems. The book was organised into a coherent order of proper perspectives, although we have over 10 contributors reviewing mainly their individual contributions. A historical perspective on the development of dielectric resonator antennas is provided in Chapter 1. Chapter 2 to 4 are more on rigorous analysis of dielectric resonator antennas of different geometries; in particular Chapter 2 on rectangular shapes, Chapter 3 on hemispherical shapes and Chapter 4 on cylindrical shapes. Although some wideband dielectric resonator antenna structures are introduced in these chapters, Chapter 5 reviews, in more detail, different bandwidth enhancement techniques, including the reduction of Q-factor by loading effect, the employment of matching networks, and the use of multiple resonators. In this era of wireless communications, low-profile and small-size antennas are highly preferable for mobile devices, such as cellular phones, notebook computers, personal digital assistant (PDA), etc. The design of low-profile dielectric resonator antennas is presented in Chapter 6, while the development of small compact circular sectored dielectric resonator antennas is described in Chapter 7. In these two chapters, techniques for the generation of circular polarisation are also included. For applications requiring high-gain antennas, dielectric resonator antenna arrays may be a good choice. Chapter 8 introduces a new perpendicular feed structure suitable for antenna arrays with active circuits. Detailed study on linearly-polarised and circularly-polarised dielectric resonator arrays are reviewed in Chapter 9. A section of a non-radiative dielectric (NRD) guide can be considered as a rectangular dielectric resonator sandwiched between two parallel plates. With the introduction of an aperture-coupled microstripline feed, this simple structure, as described in Chapter 10, becomes an efficient antenna element with reasonably high gain. This novel antenna, which is leaky and resonant in nature, is designated as a NRD res

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