Handbook of Reflector Antennas and Feed Systems: Vol. 1 - Theory and Design of Reflectors

323 Pages·2013·12.74 MB·English

by  Satish K Sharma

Handbook of Reflector Antennas
and Feed Systems
Volume I
Theory and Design of Reflectors
For a listing of recent titles in the
Artech House Antennas and Propagation Series,
turn to the back of this book.
Handbook of Reflector Antennas
and Feed Systems
Volume I
Theory and Design of Reflectors

Satish K. Sharma
Sudhakar Rao
Lotfollah Shafai
Library of Congress Cataloging-in-Publication Data
A catalog record for this book is available from the U.S. Library of Congress.
British Library Cataloguing in Publication Data
A catalog record for this book is available from the British Library.
ISBN-13: 978-1-60807-515-7
Cover design by Vicki Kane
© 2013 Artech House
All rights reserved. Printed and bound in the United States of America. No part
of this book may be reproduced or utilized in any form or by any means, elec-
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All terms mentioned in this book that are known to be trademarks or service
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10 9 8 7 6 5 4 3 2 1
Contents
Preface ix
Acknowledgments x
CHAPTER 1
Introduction 1
1.1 Introduction 1
1.2 Reflector Antenna Basics 2
1.3 Feed Sources for Reflector Antennas 6
1.4 Analysis of Reflector Antennas 6
1.5 Advanced Reflector Antenna Configurations 7
1.6 Important Fundamental Parameters 8
1.7 Organization of the Book 9
References 10
CHAPTER 2
Numerical Techniques for Reflectors 13
2.1 Introduction 13
2.2 Reflector Geometry Using a Surface of Revolution 14
2.2.1 Rays in a Parabola 14
2.3 Geometric Optics 15
2.4 Feed Modeling 16
2.4.1 Analytical Feed Models 16
2.4.2 Spherical Wave Expansion Feed 18
2.4.3 Currents Expansion Feed 19
2.5 Reflector Analysis Methods 19
2.5.1 Aperture Method 19
2.5.2 PO Analysis 23
2.5.3 GO/GTD Analysis 29
2.5.4 Shooting and Bouncing Analysis 31
2.5.5 Moment Method Reflector Analysis 32
2.6 Reflector Size Limitation 38
2.7 Struts 40
2.7.1 Polygon Struts 43
2.7.2 Metal Space Frame Radome 47
2.8 Dual Reflector 51
2.9 Dual Grid Reflector 60
v
vi Contents
2.10 Reflector Coupling 63
Acknowledgments 64
References 64
CHAPTER 3
Classical Reflector Antennas: Design Guidelines and Performance
Characteristics 67
3.1 Introduction 67
3.2 General Conic-Section-Generated Reflectors 68
3.2.1 Conic Sections 68
3.2.2 Conic-Section-Generated Reflectors 69
3.3 Parabolic Reflectors 70
3.3.1 Geometrical Parameters 71
3.3.2 Feed Patterns 72
3.3.3 Edge Tapers and Feed Tapers 77
3.3.4 Reflector Pattern Characteristics 78
3.3.5 Off-Focus Feeds 83
3.3.6 Beam Squint 94
3.3.7 Symmetric Versus Offset Parabolic Configurations 96
3.4 Folded-Optics Reflectors 97
3.4.1 Cassegrain and Gregorian Reflectors 98
3.4.2 The Equivalent Paraboloid 101
3.4.3 Feed and Subreflector Blockage 102
3.4.4 Sidelobes 102
3.4.5 Efficiency Factors 105
3.4.6 Offset Dual-Reflector Systems 106
3.4.7 Antenna Noise Temperature 108
3.4.8 Reflector Shaping 113
3.5 Other Classical Reflectors 113
3.5.1 Corner Reflectors 113
3.5.2 Spherical Reflector 115
3.5.3 Reflectors with Parabolic Arc 117
References 119
CHAPTER 4
Reflector Antennas with Adaptive Apertures 125
4.1 Introduction 125
4.2 Theory and Overview 126
4.3 Reflector Antenna Performance with Individual TE , TM , and
11 01
TE Modes of a Circular Waveguide Feed 128
21
4.4 Reflector Antenna Performance with Dual Mode Feed Horns 130
4.4.1 Symmetric Reflector with TE + TM Mode Feed Horn 131
11 01
4.4.2 Offset Reflector with TE + TM Mode Feed Horn 135
11 01
4.4.3 Symmetric Reflector with TE + TE Mode Feed Horn 139
11 21
4.4.4 Offset Reflector with TE + TE Mode Feed Horn 143
11 21
4.5 Symmetric Reflector with a Tri-Mode Circular Waveguide Feed 145
Contents vii
4.5.1 Practical Triple-Mode Feed Horn 149
4.5.2 Symmetric Reflector Antenna Performance with the
Tri-Mode Feed 154
4.6 Multiple Phase Center Offset Reflectors with TM + TM
11 21
Microstrip Patch Feeds 155
References 160
CHAPTER 5
Reflector Shaping 163
5.1 Introduction 163
5.2 Reflector Shaping Considerations 164
5.3 Reflector Shaping Techniques 166
5.4 Frequency Re-Use 168
5.5 Reflector Shaping Using Synthesis Techniques 169
5.6 Shaping Limitations and Manufacturing Aspects 176
References 178
CHAPTER 6
Bifocal and Bicollimated Dual Reflector Antennas 181
6.1 Introduction 181
6.2 Bifocal Dual Reflector Antennas 182
6.2.1 Cassegrain Configuration 182
6.2.2 Gregorian Configuration 193
6.3 Multifocal Dual Reflector Antennas 195
6.4 Bicollimated Dual Reflector Antenna 197
6.4.1 Design Procedure 199
6.4.2 Polynomial Approximation 202
6.4.3 Equivalent Gregorian Confocal Reflector 202
6.4.4 Limiting Gregorian Confocal Reflector 203
6.4.5 Phase Error Analysis 203
6.4.6 Design Example 204
6.5 Bifocal and Bicollimated Dual Reflector Antenna Applications 207
Acknowledgments 212
Appendix A: Determination of the Parameters P, L, α, and d 212
Appendix B: Three-Dimensional Ray Tracing Procedure 213
References 216
CHAPTER 7
Advanced Reflector Antennas 219
7.1 Introduction 219
7.2 Confocal Antenna System 221
7.3 Side-Fed and Front-Fed Offset Cassegrain Antenna Systems 225
7.4 Nonfocused Reflector Antenna 229
7.5 Reconfigurable Reflector Antennas 234
7.6 ADE Reflector Antennas 241
References 245
viii Contents
CHAPTER 8
Reflectarray Antennas 247
8.1 Introduction 247
8.2 General Design Guidelines 249
8.3 Aperture Efficiency of Reflectarray and Comparison with
Conventional Parabolic Reflector 253
8.3.1 Illumination Efficiency 253
8.3.2 Spillover Efficiency 254
8.3.3. Polarization Efficiency 256
8.3.4 Phase Efficiency 256
8.3.5 Blockage Efficiency 257
8.3.6 Dielectric and Conductor Loss 258
8.4 Contribution of Scattering from Constituent Components of a
Reflectarray to Its Near-Field and Far-Field Operation 259
8.5 Different Types of Reflectarray Cell Elements 264
8.6 Different Types of Reflectarray Antennas 274
Acknowledgments 284
References 289
About the Editors 295
List of Contributors 298
Index 299
Preface
Reflector antennas have received tremendous attention because they are the most
popular antenna candidate in satellite communications, radar applications, and as-
tronomical radio telescopes, to name a few. This has motivated significant progress
towards the theory and design of the reflector antennas. Most of the developments
are attributed to the evolving applications that require enhanced capability for high
data transfer rate, antenna miniaturizations, improved radiation performances,
low-cost implementation, light weight, easy installation, and most importantly, ease
in the analysis and design of the reflector antennas. My motivation to work on this
book originated from my previous research experience as a senior antenna engi-
neer at InfoMagnetics Technologies Corporation in Winnipeg, Manitoba, Canada
between May 2001 and August 2006, where I was involved in the research and
design of several reflector antenna projects for the Defense Research and Devel-
opment Canada (DRDC) and Telesat Canada. I was privileged to have numer-
ous interactions and discussions with my mentor and one of the co-editors of this
book, Professor Lotfollah Shafai. During these discussions, we thought to compile
a comprehensive resource for the antenna engineers and researchers on the reflector
antennas, feed systems, and reflector applications. Considering these three thrust
areas, we planned three volumes of a handbook in the summer of 2010. We brought
Dr. Sudhakar Rao, who has extensive research experience with reflector antenna
applications, on board to lead Volume III.
The purpose of Volume I is to present in-depth theory and design aspects of re-
flector antennas. The chapter contributors in Volume I are the leading experts from
the academia and antenna industry, whose valuable experiences have added to the
quality of this book. The book is aimed for use by practicing antenna engineers and
researchers in the industry and academia. This book starts with an introduction to
the reflector antennas in Chapter 1, which discusses conventional parabolic sym-
metric reflector antenna geometry, and ray tracing diagrams for some of the popu-
lar reflector antenna configurations. In Chapter 2, numerical methods used for the
analysis of reflector antennas are presented with a significant number of design
examples. Detailed discussion is presented on Physical Optics (PO), Geometrical
Optics (GO), Physical Theory of Diffraction (PTD), and Geometrical Theory of
Diffraction (GTD), in addition to, Method of Moment (MOM) and Time Domain
Analysis for the computation of radiation performance of the single and dual re-
flector antennas. Thus, Chapter 2 builds a solid foundation for discussing the clas-
sical reflector antenna geometries and its theory and design guidelines in Chapter 3.
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