Practical Radio-Frequency Handbook
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Practical Radio-Frequency Handbook Practical Radio-Frequency Handbook Third edition IAN HICKMAN BSc (Hons), CEng, MIEE, MIEEE Newnes OXFORD AUCKLAND BOSTON JOHANNESBURG MELBOURNE NEW DELHI Newnes An imprint of Butterworth-Heinemann Linacre House, Jordan Hill, Oxford OX2 8DP 225 Wildwood Avenue, Woburn, MA 01801–2041 A division of Reed Educational and Professional Publishing Ltd A member of the Reed Elsevier plc group First published 1993 as Newnes Practical RF Handbook Second edition 1997 Reprinted 1999 (twice), 2000 Third edition 2002 © Ian Hickman 1993, 1997, 2002 All rights reserved. No part of this publication may be reproduced in any material form (including photocopying or storing in any medium by electronic means and whether or not transiently or incidentally to some other use of this publication) without the written permission of the copyright holder except in accordance with the provisions of the Copyright, Designs and Patents Act 1988 or under the terms of a licence issued by the Copyright Licensing Agency Ltd, 90 Tottenham Court Road, London, England W1P 0LP. Applications for the copyright holder’s written permission to reproduce any part of this publication should be addressed to the publishers British Library Cataloguing in Publication Data Hickman, Ian Practical Radio-Frequency Handbook I. Title 621.384 ISBN 0 7506 5369 8 Cover illustrations, clockwise from top left: (a) VHF Log periodic antenna; (b) selection of RF coils; (c) HF receiver; (d) spectrum of IPAL TV signal with NICAM (Courtesy of Thales (a and (c)); Coilcraft (b)) Typeset at Replika Press Pvt Ltd, Delhi 110 040, India Printed and bound in Great Britain Contents Preface vii Acknowledgements xi 1 Passive components and circuits 1 Resistance and resistors 1 Capacitors 2 Inductors and transformers 6 Passive circuits 9 2 RF transmission lines 18 3 RF transformers 23 4 Couplers, hybrids and directional couplers 40 5 Active components for RF uses 49 6 RF small-signal circuitry 67 7 Modulation and demodulation 78 8 Oscillators 96 9 RF power amplifiers 122 Safety hazards to be considered 122 First design decisions 123 Levellers, VSWR protection, RF routing switches 123 Starting the design 124 Low-pass filter design 124 Discrete PA stages 127 10 Transmitters and receivers 148 11 Advanced architectures 163 12 Propagation 171 13 Antennas 181 vi Contents 14 Attenuators and equalizers 199 15 Measurements 204 Measurements on CW signals 204 Modulation measurements 205 Spectrum and network analysers 205 Other instruments 207 Appendix 1 Useful relationships 214 Appendix 2 S-Parameters 220 Appendix 3 Attenuators (pads) 225 Appendix 4 Universal resonance curve 227 Appendix 5 RF cables 228 Appendix 6 Wire gauges and related information 232 Appendix 7 Ferrite manufacturers 235 Appendix 8 Types of modulation – classification 236 Appendix 9 Quartz crystals 238 Appendix 10 Elliptic filters 240 Appendix 11 Screening 252 Appendix 12 Worldwide minimum external noise levels 261 Appendix 13 Frequency allocations 264 Appendix 14 SRDs (Short Range Devices) 268 Index 273 Preface The Practical Radio-Frequency Handbook aims to live up to its title, as a useful vade- mecum and companion for all who wish to extend their familiarity with RF technology. It is hoped that it will prove of use to practising electronic engineers who wish to move into the RF design area, or who have recently done so, and to engineers, technicians, amateur radio enthusiasts, electronics hobbyists and all with an interest in electronics applied to radio frequency communications. From this, you will see that it is not intended to be a textbook in any shape or form. Nothing would have been easier than to fill it up with lengthy derivations of formulae, but readers requiring to find these should look elsewhere. Where required, formulae will be found simply stated: they are there to be used, not derived. I have naturally concentrated on current technology but have tried to add a little interest and colour by referring to earlier developments by way of background information, where this was thought appropriate, despite the pressure on space. This pressure has meant that, given the very wide scope of the book (it covers devices, circuits, equipment, systems, radio propagation and external noise), some topics have had to be covered rather more briefly than I had originally planned. However, to assist the reader requiring more information on any given topic, useful references for further reading are included at the end of most chapters. The inclusion of descriptions of earlier developments is by no means a waste of precious space for, in addition to adding interest, these earlier techniques have a way of reappearing from time to time – especially in the current climate of deregulation. A good example of this is the super-regenerative receiver, which appeared long before the Second World War, did sterling service during that conflict, but was subsequently buried as a has-been: it is now reappearing in highly price-sensitive short-range applications such as remote garage door openers and central locking controllers. Good RF engineers are currently at a premium, and I suspect that they always will be. The reason is partly at least to be found in the scant coverage which the topic receives in university and college courses. It is simply so much easier to teach digital topics, which furthermore – due to the rapid advances being made in the technology – have long seemed the glamorous end of the business. However, the real world is analogue, and communicating information, either in analogue or digital form, at a distance and without wires, requires the use of electromagnetic radiation. This may be RF, microwave, millimetre wave or optical and there is a whole technology associated with each. This book deals just with the RF portion of the spectrum, which in earlier editions was taken to mean the range up to 1000 MHz. Frequencies beyond this were traditionally taken as the preserve of microwave engineers (sometimes, rather unfairly, called ‘plumbers’), involving waveguides, cavity resonators and the like. But with the enormous strides in technology in recent years, particularly in miniaturized surface mount components and high frequency transistors, the domain of conventional printed circuit techniques, used viii Preface at VHF and UHF, has been extended to the areas of 1.5 GHz (SOLAS, safety of life at sea, GPS and Glonas, global positioning systems), 2 GHz (PCS and DCS for mobile phones) and beyond (Bluetooth in the 2.54 GHz ISM band for short range wireless data links). In this context, an interesting and important development is the shift of large areas of RF design, away from the circuit design team at, e.g. a mobile phone manufacturer’s laboratory, to the development facilities of integrated circuit manufacturers. Thus ASICs – application specific integrated circuits – are no longer confined to the digital field. Firms such as Analog Devices, Maxim, Philips and others are steadily introducing a stream of new products integrating more and more of the receive/transmit front end for mobile phones and the corresponding base stations. Dual band ICs, for both 900 MHz and 1800 MHz bands (GSM and DCS), have appeared, with work currently in hand on 3G devices – for the third generation of mobile phones. The necessary matching passive components are also widely available, such as SAW (surface acoustic wave) filters from manufacturers such as EPCOS (formerly Siemens/Matsushita Components), Fujitsu, Murata and others. The whole frequency range, from a few kHz up to around 2.5 GHz is used for an enormous variety of services, including sound broadcasting and television, commercial, professional, government and military communications of all kinds, telemetry and telecontrol, radio telex and facsimile and amateur radio. There are specialized applications, such as short-range communications and control (e.g. radio microphones, garage door openers) whilst increasingly, RF techniques are involved in non-wireless applications. Examples are wide band cable modems, and the transmission of data with clock frequencies into the GHz range, over fibre optic cables using the FDDI (Fibre-optic digital data interchange) standard. There are also a number of more sinister applications such as ESM, ECM and ECCM (electronic surveillance measures, e.g. eavesdropping; electronic counter measures, e.g. exploitation and jamming; and electronic counter counter measures, e.g. jamming resistant radios using frequency hopping or direct sequence spread spectrum). Indeed, the pressure on spectrum space has never been greater than it is now and it is people with a knowledge of RF who have to design, produce, maintain and use equipment capable of working in this crowded environment. It is hoped that this book will prove useful to those engaged in these tasks. This third edition has a number of minor additions, deletions and corrections throughout, and substantial new material has been added to Chapters 4, 7, 8 and 13. But the main change concerns the addition of a new Chapter 11. This deals with the advanced architectures, including IF (intermediate frequency) signal processing techniques in superheterodyne receivers, and other related topics. Also important is the upgrading of Appendix 13, which gives details of frequency allocations. Annexe 1 covers the documents defining UK frequency allocations. Complete copies and further information may be obtained from the address given in the appendix. Annexe 2 likewise gives brief details of frequency allocations in the USA. Appendix 14 gives information relating to low power, short range radio devices. These represent an explosive area of growth at the present time, for a number of reasons. First, many of these devices require no licence – a great convenience to the end user – although naturally the manufacturer must ensure that such a device meets the applicable specification. Second, due to the very limited range, frequencies can be re-used almost without limit, in a way not possible in, for example, broadcast applications, or even in PMR (private mobile radio).