Handbook of Reflector Antennas and Feed Systems, Volume 2 : Feed Systems

381 Pages·2013·44.61 MB·English

by  Lotfollah Shafai

Handbook of Reflector Antennas
and Feed Systems
Volume II
Feed Systems
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For a listing of recent titles in the
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Handbook of Reflector Antennas
and Feed Systems
Volume II
Feed Systems
Sudhakar Rao
Satish K. Sharma
Lotfollah Shafai
artechhouse.com
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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: 978-1-60807-517-1
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, electronic or
mechanical, including photocopying, recording, or by any information storage and
retrieval system, without permission in writing from the publisher.
All terms mentioned in this book that are known to be trademarks or service marks
have been appropriately capitalized. Artech House cannot attest to the accuracy of this
information. Use of a term in this book should not be regarded as affecting the validity
of any trademark or service mark.
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Contents
Preface xi
CHApteR 1
Introduction 1
1.1 Introduction 1
1.2 The Feed System 3
1.3 Phase Center Determination 6
1.4 Feed Efficiency 7
1.5 Organization of the Book 9
References 11
CHApteR 2
Numerical Methods 13
2.1 Introduction 13
2.2 Maxwell’s Equations: Foundations of
Electromagnetic Analysis 14
2.2.1 Green’s Functions and Integral Representations 16
2.3 Method of Moments (MoM) 17
2.3.1 Integral Equation Formulation 18
2.3.2 Geometry Representations and Meshing 19
2.3.3 Basis Functions 22
2.3.4 Construction of the Impedance Matrix Equation 22
2.3.5 Direct and Iterative Solution Methods 23
2.3.6 Examples 24
2.4 Finite-Element Method (FEM) 28
2.4.1 Functional Formalism and Discrete Formulation 30
2.4.2 Material Modeling, Boundary Conditions, and Feed
Modeling 31
2.4.3 Discretization and Basis Functions 31
2.4.4 Example 34
2.5 Hybrid FE-BI and Domain Decomposition Techniques 35
2.5.1 Hybrid Finite-Element-Boundary Integral (FE-BI)
Formulation 35
2.5.2 Example 36
2.6 Fast Methods for Integral Equations 36
2.6.1 Fast Multipole Method (FMM) 38
2.6.2 Examples 40
v
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vi Contents
2.6.3 Model Order Reduction for Fast Frequency Sweep 41
2.6.4 Example 43
2.7 High-Frequency Techniques 43
2.7.1 Physical Optics (PO) and Geometrical Optics (GO) 43
2.7.2 Example 46
2.7.3 Geometrical Theory of Diffraction and Uniform
Theory of Diffraction 46
Acknowledgments 49
References 49
CHApteR 3
Electrically Small Feeds 51
3.1 Introduction 51
3.2 Design Requirements 53
3.3 Waveguide Feeds 56
3.3.1 Small Waveguide Feeds 57
3.3.2 Small Coaxial Feeds 64
3.3.3 Small Wide Angle Feeds 67
3.3.4 Small Backfire Feeds 70
3.4 Microstrip Feeds 74
3.4.1 Single Patch Antenna as the Reflector Feed 74
3.4.2 Planar Antenna Array Feeds 81
3.5 Backfire Printed Dipole Feeds 83
3.5.1 Design Approach 83
3.5.2 Performance Results 84
3.5.3 Printed Dipole Performance with a Reflector 89
3.6 Asymmetric Feeds 90
3.7 Feed Pattern Shaping by Superstrate Loading 92
References 93
CHApteR 4
Smooth Wall Multimode Horns for High Aperture Efficiency—
Theory, Design, and Applications 97
4.1 Introduction 97
4.2 Theory for High Aperture Efficiency 99
4.3 Circular Aperture 102
4.3.1 Realization of the Modes 103
4.3.2 Circular Horn Design 105
4.3.3 Three-Step Horn 110
4.4 Square High-Efficiency Horn 111
4.5 Multiflared High-Efficiency Horns 113
4.6 Other High-Efficiency Horn Structures 115
4.7 Applications 115
4.7.1 In Direct Radiating Arrays 115
4.7.2 In Multiple-Beam Reflectors 117
4.8 Conclusions 119
References 119
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Contents vii
CHApteR 5
Profiled Horns and Feeds 123
5.1 Introduction 123
5.2 Basis of Optimum Horns 124
5.2.1 Pattern Constraints 125
5.2.2 Input Mismatch 126
5.2.3 Aperture Efficiency 126
5.2.4 Phase Center Stability 129
5.2.5 Compactness and/or Physical Constraint Due to Existing
Environment 131
5.3 Choice of Horn Profiles 133
5.4 Optimization of Horn Profile 134
5.4.1 Possible Approaches 134
5.4.2 Optimization Methods 137
5.5 Examples of Horn Designs 139
5.5.1 Corrugated Horn 140
5.5.2 Smooth-Walled Circular and Coaxial Horns 140
5.5.3 Rectangular Horn 143
5.5.4 Dielectric Rod and Horn 145
5.5.5 Arrays of Profiled Horns 148
5.6 Conclusion 151
References 151
CHApteR 6
Soft and Hard Horn Antennas 157
6.1 Introduction to Hybrid Mode Horn Antennas 157
6.2 Definition of Soft and Hard Surfaces 158
6.3 Soft and Hard Horn Designs and Implementations 160
6.3.1 Soft Corrugated Horns 160
6.3.2 Horns with a Dielectric Core (Dielcore Horns) 162
6.3.3 Soft Strip-Loaded Horns 171
6.3.4 Hard Strip-Loaded and Corrugated Horns 172
6.3.5 Metamaterial Horns (Meta-horns) 173
6.4 Hard Horns as Feeds for Array Antennas 183
6.5 Conclusions 186
References 188
CHApteR 7
Circularly Polarized Feed Antennas 193
7.1 Introduction 193
7.2 Analysis Methods for CP Feed Antenna Design 195
7.2.1 Method of Moments (MoM) 195
7.2.2 Finite-Difference Time-Domain Method (FDTDM) 199
7.3 Polarizer and Two-Point Excitation Patch 202
7.4 One-Point Excitation CP Patch Feed Antenna 205
7.5 End-Fire Helical CP Feed Antenna 207
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viii Contents
7.5.1 Effects of a Cavity 208
7.5.2 Frequency Response 210
7.6 CP Feed Array Antenna Composed of End-Fire Helical Elements 215
7.7 Conical Helical CP Feed Antennas 219
7.8 Back-Fire-Mode CP Helical Feed Antenna 227
7.8.1 Back-Fire Radiation 227
7.8.2 Frequency Response of the Current 230
7.8.3 Effects of Pitch Angle on the Frequency Response of
the Antenna Characteristics 231
7.9 Spiral CP Feed Antenna 237
7.10 Curl CP Feed Antenna 245
7.10.1 CP Radiation 245
7.10.2 Beamwidth 247
7.10.3 Frequency Response 249
Acknowledgments 253
References 253
CHApteR 8
Generalized Asymmetric Reflector Antenna Feeds for Polarization
Control and Adaptive Virtual Array Design 257
8.1 Introduction 257
8.2 Applications of Asymmetric Feeds 260
8.2.1 Cross Polarization Reduction in Offset Reflector Antennas 261
8.3 Asymmetric Feed Designs for Cross Polarization Reduction 273
8.3.1 Feed 1: Ring Choke Excited Circular Waveguide with Slot 273
8.3.2 Feed 2: Stepped Circular Waveguide with Tuning Blocks 278
8.4 Multiphase Center Reflector Antennas and
Virtual Array Formation 282
8.4.1 The Concept Theory 283
8.4.2 Symmetrical-Cut Paraboloids 284
8.4.3 Adaptive Asymmetric Feed Designs for Multiphase
Center Applications 286
8.4.4 Feed 3: Adaptive Dual-mode TE and TE Feed 287
11 21
8.4.5 Feed 4: Adaptive Dual-mode TE and TM Feed 290
11 01
8.4.6 Feed 5: Adaptive Triple-Mode TE + TM + TE Feed 295
11 01 21
8.5 Concluding Remarks 297
References 297
CHApteR 9
Array Antennas and Low-Gain TT&C Antennas 299
9.1 Introduction 299
9.2 Array Antennas 300
9.2.1 Array Design 301
9.2.2 Radiating Elements 310
9.2.3 Array Radiation Patterns 315
9.3 Low Gain TT&C Antennas 320
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Contents ix
9.3.1 TT&C Subsystem and Antenna Applications 322
9.3.2 TT&C Antennas Introduction 324
9.3.3 TT&C RF Block Diagram and Link Budgets 327
9.3.4 Low-Gain TT&C Antennas 328
References
About the Editors 351
Index 355
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