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WAVE PROPAGATION AND

ANTENNA ENGINEERINGSanjay Kumar • Saurabh Shukla

The book is primarily designed to cater to the needs of undergraduate and postgraduate students of Electronics and Communication Engineering and allied branches. It also caters to fundamental requirements of professionals working on design and development of antenna and wave propagation related equipment either in research laboratories or industries or academic institutions elsewhere.

The book has been written with intent to grasp the basic understanding of theoretical as well as practical aspects of electromagnetic wave propagation and antenna engineering. The text has been aptly scripted considering the requirements of average students who can easily grasp and comprehend the basics of wave propagation and radiation mechanism of varieties of antennas coupled with their critical functionalities, utilities, advantages/disadvantages without any external assistance of teachers or other reference books. The book broaches very well on practical methods of parametric measurements of antenna with right measuring test equipment and associated tools. The last chapter of the book is dedicated to advance technology adopted in design and development of modern antenna.

KEY FEATURES

m A fairly large number of well labelled diagrams to provide practical understanding of the concepts.

m The placement of numericals at appropriate places develops confidence among readers and enthuses them further to read in depth to crack any regular or competitive examinations.

m Chapter summary highlights important points for quick recap and revision before examination.

m Well-crafted multiple choice questions with answers at the end of each chapter to stimulate thought process and prepare better for viva-voce and competitive examinations.

m Appropriate number of unsolved numerical problems with answers to improve problem solving skill of students.

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ISBN:978-81-203-5104-2

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THE AUTHORS

SANJAY KUMAR, Ph.D. (IIT Delhi) is Air Commodore (Retd.). He has commanded premier technical bases of IAF and possesses very sound engineering and administrative acumen. He has 31 years of work experience in various formations of IAF, labs of DRDO as designer, developer and Principal Adviser of various projects and Program Director of Electronic Warfare Project of aircraft at DARE, DRDO. He has published large number of research papers in national and international journals.

Dr. Sanjay Kumar is member of Editorial Board of International Journal of Engineering, Science and Management (ISSN no. 2231–3273). Also, he is member of IIT Delhi Alumni Association and life time member of IETE. He has been question paper setter, teacher and evaluator of Research Methodology for Osmania University, Hyderabad for three years. He is recipient of AVM Harjinder Singh Trophy for best academic performance at AFTC, Bangalore. For his outstanding contribution he has been commended by Chief of the Air Staff and Air Officer Commanding-in-Chief, TC, IAF.

SAURABH SHUKLA, is Scientist, Defence Avionics Research Establishment (DARE). He has eight years of professional experience in design and development of wideband antennas and passive microwave devices. He has also served as Scientist 'B' in Defence Institute of Advance Technology, Pune.

He is the member of IEEE and Alumni Association of NIT, Hamirpur. He was also the member of Association of Old Crows (AOC), USA (2010–2012). He was awarded by Special Technology Award for Evaluation/Integration of RF Subsystems of EW-Suite of MiG-27 Aircraft (2010) from DARE, DRDO, Bangalore.

Kumar •

Shukla

WAVE PROPAGATION

AND ANTENNA ENGINEERING

Wave Propagation and Antenna Engineering

Wave Propagation and Antenna Engineering

SANJAY KUMARAir Commodore (Retd.)

Former AOC, 9 BRD, IAF Pune and

Former Principal AdviserDefence Avionics Research Establishment (DARE)

DRDO, Bangalore

SAURABH SHUKLAScientist

Defence Avionics Research Establishment (DARE)DRDO, Bangalore

Delhi-1100922016

WAVE PROPAGATION AND ANTENNA ENGINEERINGSanjay Kumar and Saurabh Shukla

© 2016 by PHI Learning Private Limited, Delhi. All rights reserved. No part of this book may be reproduced in any form, by mimeograph or any other means, without permission in writing from the publisher.

ISBN-978-81-203-5104-2

The export rights of this book are vested solely with the publisher.

Published by Asoke K. Ghosh, PHI Learning Private Limited, Rimjhim House, 111, Patparganj Industrial Estate, Delhi-110092 and Printed by Mohan Makhijani at Rekha Printers Private Limited, New Delhi-110020.

Dedicated to Our Beloved Parents

Contents

Preface xvii

1. Fundamentals of Electromagnetics 1–47 1.1 Introduction 1 1.2 Spherical Coordinate System 1 1.3 Electromagnetic (EM) Spectrum 3 1.4 International Telecommunication Union (ITU) 4 1.5 Institute of Electrical and Electronics Engineers (IEEE) 5 1.6 Some Important Vector Operations 6 1.7 Time and Frequency Domain Representation 8 1.8 Maxwell’s Equations 8 1.9 Helmholtz Equation or Vector Wave Equation 11 1.10 Relationship between Decibels and Nepers 12 1.11 Types of Medium 14 1.11.1 Wave Equation in Free Space 14 1.11.2 Wave Equation in Conductor (or Conducting Medium) 15 1.11.3 Wave Equation in Good Conductor (or Good Conducting Medium) 16 1.11.4 Wave Propagation in Lossless Dielectric (or Good Dielectric) 18 1.12 Skin Depth 20 1.13 Equation of Uniform Plane Wave 21 1.14 Poynting Theorem and Poynting Vector 23 1.15 Polarisation of Electromagnetic Wave 26 1.16 Reflection andTransmissionofEM Waves 29 1.17 Transmission Lines 32 1.18 Smith Chart 36 Summary 42 Review Questions 44 Multiple Choice Questions 44 Numerical Problems 47

2. Wave Propagation-I: Ground and Space Wave Propagation 48–95 2.1 Introduction 48 2.2 Radio Wave Propagation 48

vii

viii Contents

2.3 Ground Wave (Surface Wave) 49 2.3.1 Application 50 2.3.2 Field Strength at Finite Distance due to Ground Waves 51 2.4 Reflection fromFlatEarth 58 2.4.1 ReflectionCoefficient ofHorizontalPolarisedWave 60 2.4.2 ReflectionCoefficient ofVerticalPolarisedWave 62 2.5 Wave Tilt of Surface Wave 63 2.6 Friis Free Space Equation 65 2.7 Space Wave or Tropospheric Wave Propagation 68 2.7.1 Space Wave Field Strength 69 2.7.2 Normal Refraction 73 2.7.3 Radio Horizon: Line of Sight (LOS) for Space Waves 74 2.7.4 Equivalent Radius of Earth 78 2.8 Factors Affecting Space Wave Propagation 82 2.8.1 Effect of the Curvature of Earth’s Surface 82 2.8.2 Effect of Earth’s Imperfections and Roughness 83 2.8.3 Effect of Hills, Buildings and Other Obstacles 83 2.8.4 Field Strength Variation with Height 83 2.8.5 Effect of Polarisation of Space Wave 84 2.8.6 Effect of Transition between Ground Wave and Space Wave 84 2.9 Atmospheric Effects in Space Wave Propagation 85 2.9.1 Refractive Index of Air 85 2.9.2 Duct Propagation 87 2.9.3 Tropospheric Scattering 88 Summary 89 Review Questions 91 Multiple Choice Questions 92 Numerical Problems 94

3. Wave Propagation-II: Ionospheric Wave Propagation 96–138 3.1 Introduction 96 3.2 Earth’s Atmosphere 96 3.2.1 Troposphere 96 3.2.2 Stratosphere 97 3.2.3 Ionosphere 97 3.3 Sky Wave or Ionospheric Wave Propagation 100 3.3.1 Refractive Index of Ionosphere 100 3.3.2 Plasma and Plasma Frequency (fp) 102 3.3.3 Critical Frequency (fc) 103 3.3.4 Maximum Usable Frequency (MUF) 104 3.3.5 Maximum Usable Frequency (fMUF) for Short Distance Communication 106 3.3.6 Maximum Usable Frequency (fMUF) for Long Distance Communication 107

Contents ix 3.3.7 Optimum Working Frequency (OWF) 113 3.3.8 Lowest Usable Frequency (LUF) 114 3.3.9 Skip Distance 115 3.3.10 Skip Zone (Dead Zone) 117 3.3.11 Actual and Virtual Height 117 3.4 Fading 119 3.4.1 Multipath Fading 120 3.4.2 Selective Fading 120 3.4.3 Interference Fading 120 3.4.4 Absorption Fading 121 3.4.5 Polarisation Fading 121 3.4.6 Skip Fading 121 3.5 Diversity Schemes 121 3.5.1 Time Diversity 122 3.5.2 Frequency Diversity 122 3.5.3 Space Diversity 122 3.5.4 Polarisation Diversity 122 3.6 Transmission Losses 122 3.7 Effect of Earth’s Magnetic Field 123 3.7.1 Expression for Gyrofrequency 124 3.7.2 Magneto-Ionic Theory 125 3.7.3 Magneto-Ionic Splitting 126 3.8 Faraday Rotation 127 3.9 Variations in the Ionosphere 129 3.9.1 Regular Variations 130 3.9.2 Irregular Variations 131 3.10 Energy Losses Due to Collisions in Ionosphere 132 Summary 133 Review Questions 134 Multiple Choice Questions 135 Numerical Problems 137

4. Antenna Fundamentals 139–203 4.1 Introduction 139 4.2 Isotropic Radiator 139 4.3 Average Power from an Isotropic Antenna 141 4.4 Radiation Mechanism 141 4.5 Types of Antenna 145 4.6 Fundamental Antenna Parameters 146 4.6.1 Antenna Input Impedance 147 4.6.2 Antenna VSWR and Return Loss 149 4.6.3 Antenna Bandwidth 151 4.6.4 Radiation Pattern 152 4.6.5 Antenna Radiation Lobes 155

Wave Propagation And AntennaEngineering

Publisher : PHI Learning ISBN : 9788120351042Author : KUMAR, SANJAY, SHUKLA, SAURABH

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