Microwaves and Wireless Simplified
Microwaves and Wireless Simplified Second Edition For a complete listing of the Artech House Microwave Library, turn to the back of this book. Microwaves and Wireless Simplified Second Edition Thomas S. Laverghetta a r techhouse. com Library of Congress Cataloging-in-Publication Data Laverghetta, Thomas S. Microwaves and wireless simplified / Thomas S. Laverghetta.—2nd ed. p. cm.—(The Artech House microwave library) Includes bibliographical references and index. ISBN 1-58053-943-2 (alk. paper) 1. Microwave devices. 2. Microwave communication systems. I. Title. II. Series. TK7876.L382 2005 621.381’3—dc22 2005043575 British Library Cataloguing in Publication Data Laverghetta, Thomas S. Microwaves and wireless simplified.—2nd ed.—(Artech House microwave library) 1. Microwave devices 2. Microwave communication systems I. Title 621.3’813 ISBN 1-58053-943-2 Cover design by Igor Valdman © 2005 ARTECH HOUSE, INC. 685 Canton Street Norwood, MA 02062 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, in - cluding photocopying, recording, or by any information storage and retrieval system, with - out 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 informa - tion. Use of a term in this book should not be regarded as affecting the validity of any trade - mark or service mark. International Standard Book Number: 1-58053-943-2 10 9 8 7 6 5 4 3 2 1 Contents Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . ix 1 Introduction . . . . . . . . . . . . . . . . . . . . . . 1 Reference 12 2 Microwave Applications . . . . . . . . . . . . . . . 13 2.1 Radar . . . . . . . . . . . . . . . . . . . . . . . . . . 14 2.1.1 Tracking and measurement applications . . . . . . . . . . 19 2.1.2 Imaging applications . . . . . . . . . . . . . . . . . . 19 2.1.3 Doppler radar. . . . . . . . . . . . . . . . . . . . . 22 2.2 Telephones and telephone systems . . . . . . . . . . . . . . 26 2.3 Telecommunications . . . . . . . . . . . . . . . . . . . 32 2.4 Navigational Technology (GPS) . . . . . . . . . . . . . . . 42 2.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . 48 Reference 48 3 Transmission Lines . . . . . . . . . . . . . . . . . . 49 3.1 Coaxial transmission lines . . . . . . . . . . . . . . . . . 56 3.1.1 Flexible coaxial transmission line . . . . . . . . . . . . . 58 3.1.2 Semirigid cable . . . . . . . . . . . . . . . . . . . . 63 3.2 Strip transmission line (stripline) . . . . . . . . . . . . . . 67 3.3 Microstrip . . . . . . . . . . . . . . . . . . . . . . . . 71 3.4 Coplanar waveguide . . . . . . . . . . . . . . . . . . . . 74 3.5 Waveguide . . . . . . . . . . . . . . . . . . . . . . . . 77 3.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . 83 Reference 85 4 Microwave Components . . . . . . . . . . . . . . . 87 4.1 Directional couplers . . . . . . . . . . . . . . . . . . . . 88 4.1.1 Monitor circuits . . . . . . . . . . . . . . . . . . . . 93 4.1.2 Leveling circuits . . . . . . . . . . . . . . . . . . . . 95 4.1.3 Power measurement . . . . . . . . . . . . . . . . . . 96 4.1.4 Reflectometers. . . . . . . . . . . . . . . . . . . . . 97 4.2 Quadrature hybrids . . . . . . . . . . . . . . . . . . . . 99 4.2.1 Matched detectors. . . . . . . . . . . . . . . . . . . 103 4.2.2 Combining amplifiers . . . . . . . . . . . . . . . . . 105 4.2.3 SPST switches . . . . . . . . . . . . . . . . . . . . 106 4.3 Power dividers . . . . . . . . . . . . . . . . . . . . . . 107 4.4 Detectors . . . . . . . . . . . . . . . . . . . . . . . . 112 4.5 Mixers . . . . . . . . . . . . . . . . . . . . . . . . . 119 4.5.1 Elements of a mixer circuit . . . . . . . . . . . . . . . 122 4.5.2 Signals in a mixer circuit . . . . . . . . . . . . . . . . 123 4.6 Attenuators . . . . . . . . . . . . . . . . . . . . . . . 126 4.7 Filters . . . . . . . . . . . . . . . . . . . . . . . . . 131 4.7.1 Bandpass filters. . . . . . . . . . . . . . . . . . . . 132 4.7.2 Lowpass filters . . . . . . . . . . . . . . . . . . . . 137 4.7.3 Highpass filters . . . . . . . . . . . . . . . . . . . . 140 4.8 Circulators and isolators . . . . . . . . . . . . . . . . . 141 4.9 Antennas . . . . . . . . . . . . . . . . . . . . . . . . 150 4.10 Amplifiers . . . . . . . . . . . . . . . . . . . . . . . 155 4.10.1 Low-Noise Amplifiers . . . . . . . . . . . . . . . . 159 Microwaves and Wireless Simplified 4.10.2 Low-Level Linear Amplifiers . . . . . . . . . . . . . . 160 4.10.3 Power Amplifiers . . . . . . . . . . . . . . . . . . 160 4.11 Oscillators . . . . . . . . . . . . . . . . . . . . . . . 162 4.12 Summary . . . . . . . . . . . . . . . . . . . . . . . 169 5 Solid State Devices . . . . . . . . . . . . . . . . . 171 5.1 Microwave diodes . . . . . . . . . . . . . . . . . . . . 175 5.1.1 Schottky diodes . . . . . . . . . . . . . . . . . . . . 175 5.1.2 PIN diodes . . . . . . . . . . . . . . . . . . . . . 180 5.1.3 Tunnel diodes . . . . . . . . . . . . . . . . . . . . 183 5.1.4 Gunn diodes . . . . . . . . . . . . . . . . . . . . . 187 5.2 Microwave transistors. . . . . . . . . . . . . . . . . . . 189 5.2.1 Bipolar transistors . . . . . . . . . . . . . . . . . . 192 5.2.2 Field effect transistors (FETs) . . . . . . . . . . . . . . 200 5.2.3 Heterojunction bipolar transistor (HBT) . . . . . . . . . 206 5.2.4 High electron mobility transistors (HEMTs) . . . . . . . . 210 5.3 Solid-state techniques. . . . . . . . . . . . . . . . . . . 212 5.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . 222 Reference 223 6 Microwave Materials . . . . . . . . . . . . . . . . 225 6.1 Definition of terms . . . . . . . . . . . . . . . . . . . . 226 6.2 Material requirements . . . . . . . . . . . . . . . . . . 236 6.3 Types of materials . . . . . . . . . . . . . . . . . . . . 238 6.3.1 Teflon fiberglass materials . . . . . . . . . . . . . . . 238 6.3.2 Non-PTFE materials . . . . . . . . . . . . . . . . . 243 6.3.3 Thermoset polymer composites . . . . . . . . . . . . . 245 6.4 Choice of materials . . . . . . . . . . . . . . . . . . . . 246 6.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . 247 Glossary . . . . . . . . . . . . . . . . . . . . . . . 249 About the Author . . . . . . . . . . . . . . . . . . 259 Index . . . . . . . . . . . . . . . . . . . . . . . . 261 Contents Preface Every technical book that is written has a definite lifetime. This is true if it is a highly theoretical book or a book such as this one, which simplifies a highly technical field. This is why you see first editions, second editions, and so on. There is nothing wrong with this arrangement and it actually is a natural pro- gression since it keeps the reader up-to-date with the most recent advances in a particular field. The first edition of this book was published in 1998 and such chapters as Chapters 2, 5, and 6 (Microwave Applications, Solid State Devices, and Microwave Materials, respectively) were based on what technology was avail - able in 1998. This is now the twenty-first century, however, and many things have changed since 1998. Chapters 2, 5, and 6 are the focus of this second edi - tion, but Chapters 1, 3, and 4 are also revised to make the field of microwaves much more understandable to anyone who is not a microwave technician or engineer. That has always been the objective of Microwaves and Wireless Sim - plified—to present an easily understandable explanation of the topics of microwaves and wireless communications to anyone in marketing or adver - tising or to anyone who just wants to know more about the subjects. [...]...x Microwaves and Wireless Simplified Chapter 1 has some clarification of microwave points and terms to bring them up-to-date with the rest of the book Chapter 2 includes many applications such as wireless local area networks (WLAN), radio frequency identification (RFID), and a section on the global positioning system (GPS) Chapter 3 now includes a section on waveguide and its applications in microwaves. .. waves that require special circuit-fabrication techniques With a definition set forth, it now is time to get into the terminology of microwaves and wireless technology, that is, the jargon and the buzz words used by those in the microwave field 4 Microwaves and Wireless Simplified The first term we will look at is decibel (dB) A decibel, which is a relative term with no units, is a ratio of two powers... between the center conductor and the outer shield of a coaxial cable and measure anything but an open circuit (A coaxial cable is a transmission line with a center conductor surrounded by a dielectric material +10 dBm -1 dB +9 dBm +19 dBm +31 dBm +10 dB +12 dB +26 dBm -5 dB Figure 1.2 Decibels and decibels referred to milliwatts +24 dBm -2 dB 6 Microwaves and Wireless Simplified and an outer shield This... of a standing wave, consider a rope tied to a post If you hold the rope in your hand and flip your wrist up and down, you see a wave going down the rope to the post If the post and the rope were matched to each other, the wave going down the rope would be completely absorbed into the post and you would not see it again In reality, however, the post and the rope are not matched to each other and the... still is a short to dc and will short your current to ground Remember that a short circuit is a short at 0 Hz (dc), at 1 kHz, at 10 MHz, at 20 GHz, and so on It is always a short, so remember to correct for it One term that is used often but usually not defined is wireless, which means exactly what it says, “without wires.” In a wireless communications 10 Microwaves and Wireless Simplified system, there... text, and they will be defined and explained as they appear There is also a glossary in the back of the text Now it is time to get into the actual microwave and wireless applications and operations Reference [1] Laverghetta, T.S., Modern Microwave Measurements and Techniques, Norwood, MA: Artech House, 1988 2 Microwave Applications Now it is time to get into some common applications of microwave and wireless. .. be categorized as follows: search and warning, tracking and measurement, imaging (identification), and control and communications 2.1.1 Tracking and measurement applications The tracking and measurement function of radar is the one most people think of when they hear the word radar It is the detection of a target (an airplane in the air, a land mass on a radar scope, and so forth) Such targets usually... and makes a three-dimensional picture of it to give doctors a much better picture of what they are dealing with 20 Microwaves and Wireless Simplified Figure 2.4 Tracking radar Figure 2.5 Imaging radar Mircowave Applications 21 Figure 2.6 Imaging radar display 22 Microwaves and Wireless Simplified 2.1.3 Doppler radar We now look at a special-condition radar, Doppler Doppler radar was originally conceived... Microwaves and Wireless Simplified Let us take a look at the electromagnetic spectrum and, in particular, the microwave spectrum, to further understand what frequencies we are talking about when we discuss applications or other aspects of microwaves Figure 2.1 is a drawing of the electromagnetic spectrum Notice that it covers a wide range of frequencies, from a few megahertz to the visible light spectrum and. .. available, spread it over a long period of time, and Time (a) τ T (b) Figure 2.3 Radar signals 18 Microwaves and Wireless Simplified have it be a small amplitude, or you take the same amount of energy, have it on for a short period of time, and have it be a much higher amplitude That is the idea behind the short-duration, high-amplitude pulse systems To understand a pulse system, you must be familiar with . mation on microwaves and wireless components and systems to allow you to be very familiar with each of the topics. x Microwaves and Wireless Simplified. of microwaves much more understandable to anyone who is not a microwave technician or engineer. That has always been the objective of Microwaves and Wireless