Wireless Communication Electronics

Wireless Communication Electronics

Robert Sobot Wireless Communication Electronics Introduction to RF Circuits and Design Techniques 123

Robert Sobot Department of Electrical and Computer Engineering The University of Western Ontario Richmond Street 1151 N6A 5B8 London, ON Canada ISBN 978-1-4614-1116-1 e-isbn 978-1-4614-1117-8 DOI 10.1007/978-1-4614-1117-8 Springer New York Dordrecht Heidelberg London Library of Congress Control Number: 2012930048 Springer Science+Business Media, LLC 2012 All rights reserved. This work may not be translated or copied in whole or in part without the written permission of the publisher (Springer Science+Business Media, LLC, 233 Spring Street, New York, NY 10013, USA), except for brief excerpts in connection with reviews or scholarly analysis. Use in connection with any form of information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed is forbidden. The use in this publication of trade names, trademarks, service marks, and similar terms, even if they are not identified as such, is not to be taken as an expression of opinion as to whether or not they are subject to proprietary rights. Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com)

To Allen

Preface This textbook originated in my lecture notes for the Communication Electronics I undergraduate course that I have offered over the last six years to the students at The University of Western Ontario in London Ontario, Canada. The book covers the transitional area between low frequency and high frequency wireless circuits. Specifically, it introduces the fundamental physical principles related to the operation of a typical wireless radio communication system. By no means have I attempted to touch upon all the possible topics related to wireless transmission systems. Most modern textbooks cover a large number of topics with relatively low level of details, which are usually left as an exercise to the reader. In this textbook I have chosen to discuss the subject in more depth, and thus provide detailed mathematical derivations, applied approximations, and analogies. The chosen topics are, in my experience, suitable for a one semester, four hours per week, senior undergraduate engineering course. My intent was to tell a logical story that flows smoothly from one chapter to the next, hoping that the reader will find it easy to follow. My main inspiration in writing this book came from my students, who at the beginning of the semester would always ask: What do I need to study for this course?. Having a choice between writing a textbook that covers many topics at a high level, or the one that covers fewer fundamental principles but in more detail, I choose the latter. All of the material in this book is considered the basic knowledge that is expected to have been acquired by aspiring engineers entering the field of wireless communication electronics. Therefore, the intended audience for this book are, primarily, senior undergraduate engineering students preparing for their carriers in communication electronics. At the same time, my hope is that graduate engineering students will find this book a useful reference for some of the topics that have been only touched upon in the previous stages of their education, or are explained from a different point of view. Finally, the practicing junior RF engineers may find this book a handy source for the quick answers that are routinely omitted from most textbooks. London ON, Canada Robert Sobot vii

Acknowledgements I would like to acknowledge all those wonderful books that I used as references and the source of my knowledge, and to say thank you to their authors for providing me with the insights that otherwise I would not have been able to acquire. Under their influence, I was able to expand my own picture of reality, which is what acquiring of the knowledge is all about. My hope is that their guidance and shaping of my own understanding of the topics in this book are clearly visible, hence I do want to acknowledge their contributions, which are now being passed on to my readers. In professional life one learns both from written sources and from experience. The experience comes from the interaction with people that we meet and projects that we work on. I am grateful to my former colleagues who I was fortunate to have as my technical mentors on really inspirational projects, first at the Institute of Microelectronic Technologies and Single Crystals, University of Belgrade, former Yugoslavia, then at PMC Sierra Burnaby BC, Canada, where I gained most of my experiences of the real engineering world. I would like to acknowledge the contributions of Professor John MacDougall, who initialized and restructured the course into the form of design and build, and of Professors Alan Webster, Zine Eddine Abid, and Serguei Primak who taught the course at various times. I would like to thank all of my former and current students who relentlessly keep asking Why? and How did you get this?. I hope that the material compiled in this book contains answers to at least some of those questions and that it will encourage them to keep asking questions with unconstrained curiosity about all the phenomena that surround us. Sincere gratitude goes to my publisher and editors for their support and making this book possible. Most of all, I want to thank my wife for being my loyal supporter, and to our son for always hanging around my desk and for making me laugh. ix

Contents 1 Introduction... 1 1.1 Fundamental Concepts in Physics... 1 1.2 Wireless Transmission of Signals... 2 1.2.1 A Short History of Wireless Technology... 2 1.3 Nature of Waves... 5 1.4 Wave Characteristics... 8 1.4.1 Amplitude... 9 1.4.2 Frequency... 9 1.4.3 Envelope... 10 1.4.4 Phase, Group, and Signal Velocity... 11 1.4.5 Wavelength... 12 1.4.6 Multitone Waveform... 15 1.4.7 Frequency Spectrum... 16 1.5 Electromagnetic Waves... 17 1.5.1 Tuning... 19 1.5.2 Maxwell s Equations... 20 1.5.3 The Concept of High Frequency... 24 1.6 RF Communication Systems... 26 1.7 Summary... 27 Problems... 28 2 Basic Terminology... 31 2.1 Matter and Electricity... 31 2.2 Electromotive Force... 31 2.3 Electric Current Effects... 33 2.4 Conductors, Semiconductors, and Insulators... 33 2.5 Basic Electrical Variables... 34 2.5.1 Voltage... 34 2.5.2 Current... 35 2.5.3 Power... 37 2.5.4 Impedance... 37 2.6 Electronic Signals... 39 2.6.1 Properties of a Sine Wave... 39 2.6.2 DC and AC Signals... 43 2.6.3 Single-Ended and Differential Signals... 44 2.6.4 Constructive and Destructive Signal Interactions... 45 xi

xii Contents 2.7 Signal Quantification... 46 2.7.1 AC Signal Power... 46 2.7.2 The Decibel Scale... 48 2.7.3 The Meaning of Ground... 49 2.8 Summary... 50 Problems... 50 3 Electrical Noise... 53 3.1 Thermal Noise... 53 3.2 Equivalent Noise Bandwidth... 56 3.2.1 Noise Bandwidth in an RC Network... 56 3.2.2 Noise Bandwidth in an RLC Network... 57 3.3 Signal to Noise Ratio... 58 3.4 Noise Figure... 59 3.5 Noise Temperature... 60 3.6 Noise Figure of Cascaded Networks... 62 3.7 Noise in Active Devices... 64 3.8 Summary... 65 Problems... 65 4 Electronic Devices... 67 4.1 Simple Circuit Elements... 67 4.1.1 Simple Conductive Wire... 67 4.1.2 Ideal Voltage Source... 71 4.1.3 Ideal Current Source... 72 4.1.4 Resistance... 73 4.1.5 Capacitance... 77 4.1.6 Inductance... 84 4.1.7 Transformer... 89 4.1.8 Memristance... 98 4.1.9 Voltage Divider... 99 4.2 Basic Network Laws... 104 4.2.1 Ohm s Law... 105 4.2.2 Kirchhoff s Laws... 105 4.2.3 Thévenin and Norton s Transformations... 106 4.3 Semiconductor Devices... 107 4.3.1 Doped Semiconductor Material... 107 4.3.2 P N Junction... 109 4.3.3 Diode... 110 4.3.4 Bipolar Junction Transistor... 113 4.3.5 MOS Field-Effect Transistor... 119 4.3.6 Junction Field-Effect Transistor... 120 4.4 Summary... 122 Problems... 122 5 Electrical Resonance... 127 5.1 The LC Circuit... 127 5.1.1 Damping and Maintaining Oscillations... 129 5.1.2 Forced Oscillations... 133 5.2 The RLC Circuit... 135 5.2.1 Serial RLC Network... 135 5.2.2 Parallel RLC Network... 138

Contents xiii 5.3 Q Factor... 139 5.3.1 Q Factor of a Serial RLC Network... 141 5.3.2 Q Factor of a Parallel RLC Network... 142 5.4 Self-resonance of an Inductor... 144 5.5 Serial to Parallel Impedance Transformations... 145 5.6 Dynamic Resistance... 146 5.7 General RLC Networks... 147 5.7.1 Derivation for the Resonant Frequency ω 0... 148 5.7.2 Derivation for the Dynamic Resistance R D... 150 5.8 Selectivity... 151 5.9 Bandpass Filters... 151 5.10 Coupled Tuned Circuit... 154 5.11 Summary... 154 Problems... 155 6 Matching Networks... 157 6.1 System Partitioning Concept... 157 6.2 Maximum Power Transfer... 158 6.3 Measuring Power Loss Due to Mismatch... 160 6.4 Matching Networks... 161 6.5 Impedance Transformation... 162 6.6 The Q Matching Technique... 162 6.6.1 Matching Real Impedances... 163 6.6.2 Matching Complex Impedances... 166 6.7 Bandwidth of a Single-Stage LC Matching Network... 168 6.7.1 Increasing Bandwidth with Multisection Impedance Matching... 169 6.7.2 Decreasing Bandwidth with Multisection Impedance Matching... 170 6.8 Summary... 171 Problems... 171 7 RF and IF Amplifiers... 173 7.1 General Amplifiers... 173 7.1.1 Amplifier Classification... 174 7.1.2 Voltage Amplifier... 175 7.1.3 Current Amplifier... 178 7.1.4 Transconductance Amplifier... 181 7.1.5 Transresistance Amplifier... 182 7.2 Single-Stage Amplifiers... 183 7.2.1 Common-Base Amplifier... 183 7.2.2 Common-Emitter Amplifier... 188 7.2.3 Common-Collector Amplifier... 192 7.3 Cascode Amplifier... 196 7.4 The Biasing Problem... 197 7.4.1 Emitter-Degenerated CE Amplifier... 200 7.4.2 Voltage Divider for Biasing Control... 201 7.4.3 Two-Stage Biasing Control... 203 7.5 AC Analysis of Voltage Amplifiers... 206 7.6 Miller Capacitance... 207 7.7 Tuned Amplifiers... 209 7.7.1 Single-Stage CE RF Amplifier... 210 7.7.2 Single-Stage CB RF Amplifier... 216 7.7.3 Insertion Loss... 217

xiv Contents 7.8 Summary... 217 Problems... 218 8 Sinusoidal Oscillators... 221 8.1 Criteria for Oscillations... 221 8.2 Ring Oscillators... 223 8.3 Phase-Shift Oscillators... 224 8.4 RF Oscillators... 225 8.4.1 Tapped L, Centre-Grounded Feedback Network... 225 8.4.2 Tapped C, Centre-Grounded Feedback Network... 228 8.4.3 Tapped L, Bottom-Grounded Feedback Network... 228 8.4.4 Tapped C, Bottom-Grounded Feedback Network... 229 8.4.5 Tuned Transformer... 229 8.5 Amplitude-Limiting Methods... 231 8.5.1 Automatic Gain Control... 231 8.5.2 Clamp Biasing... 231 8.5.3 Gain Reduction with Temperature-Dependent Resistors... 232 8.5.4 Device Saturation with Tuned Output... 232 8.6 Crystal-Controlled Oscillators... 232 8.7 Voltage-Controlled Oscillators... 234 8.8 Time and Amplitude Jitter... 238 8.9 Summary... 239 Problems... 239 9 Frequency Shifting... 241 9.1 Signal-Mixing Mechanism... 241 9.2 Diode Mixers... 243 9.3 Transistor Mixers... 245 9.4 JFET Mixers... 246 9.5 Dual-Gate MOSFET Mixers... 247 9.6 Image Frequency... 249 9.6.1 Image Rejection... 249 9.6.2 LC Tank Admittance... 250 9.7 Summary... 251 Problems... 251 10 Phase-Locked Loops... 253 10.1 PLL Operational Principles... 253 10.2 Linear Model of PLL... 254 10.2.1 Phase Detector Model... 255 10.2.2 VCO Model... 256 10.2.3 PLL Bandwidth... 257 10.2.4 The Loop Filter Model... 259 10.3 PLL Applications... 260 10.3.1 Frequency Synthesizers... 260 10.3.2 Clock and Data Recovery Units (CRU)... 261 10.3.3 Tracking Filters... 261 10.4 Summary... 261 Problems... 262 11 Modulation... 263 11.1 The Need for Modulation... 263

Contents xv 11.2 Amplitude Modulation... 265 11.2.1 Trapezoidal Patterns and the Modulation Index... 267 11.2.2 Frequency Spectrum of Amplitude-Modulated Signal... 268 11.2.3 Average Power... 268 11.2.4 Double-Sideband and Single-Sideband Modulation... 270 11.2.5 The Need for Frequency and Phase Synchronization... 273 11.2.6 Amplitude Modulator Circuits... 274 11.3 Angle Modulation... 281 11.3.1 Frequency Modulation... 282 11.3.2 Phase Modulation... 287 11.3.3 Angle Modulator Circuits... 288 11.4 PLL Modulator... 291 11.5 Summary... 292 Problems... 292 12 AM and FM Signal Demodulation... 295 12.1 AM Demodulation Principles... 295 12.2 Diode AM Envelope Detector... 296 12.2.1 Ripple Factor... 297 12.2.2 Detection Efficiency... 298 12.2.3 Input Resistance... 301 12.2.4 Distortion Factor... 303 12.3 FM Wave Demodulation... 305 12.3.1 Slope Detectors and FM Discriminators... 307 12.3.2 Quadrature Detector... 312 12.3.3 PLL Demodulator... 315 12.4 Summary... 315 Problems... 316 13 RF Receivers... 319 13.1 Basic Radio Receiver Topologies... 319 13.2 Nonlinear Effects... 321 13.2.1 Harmonic Distortion... 323 13.2.2 Inter-Modulation... 325 13.2.3 Cross-Modulation... 328 13.2.4 Image Frequency... 329 13.3 Radio Receiver Specifications... 331 13.3.1 Dynamic Range... 331 13.4 Summary... 333 Problems... 334 A Physical Constants and Engineering Prefixes... 335 B Maxwell s Equations... 337 C Second-Order Differential Equation... 339 D Complex Numbers... 341 E Basic Trigonometric Identities... 343 F Useful Algebraic Equations... 345 G Bessel Polynomials... 347

xvi Contents Bibliography... 349 Glossary... 351 Solutions... 357 Index... 383

Abbreviations AC A/D ADC AF AFC AGC AM BiCMOS BJT BW CMOS CRTC CW D/A DAC db dbm DC ELF EM ev FCC FET FFT FM GaAs GHz HBT HF Hz IC IF InGaAs InP I/O IR Alternating current Analogue to digital Analogue to digital converter Audio frequency Automatic frequency control Automatic gain control Amplitude modulation Bipolar-CMOS Bipolar junction transistor Bandwidth Complementary metal-oxide semiconductor Canadian Radio-Television and Telecommunication Commission Continuous wave Digital to analogue Digital to analogue converter Decibel Decibel with respect to 1 mw Direct current Extremely low frequency Electromagnetic Electron volts Federal communication commision Field effect transistor Fast Fourier transform Frequency modulation Gallium arsenide Gigahertz Heterojunction bipolar transistor High frequency Hertz Integrated circuit Intermediate frequency Indium gallium arsenide Indium phosphide Input output Infrared xvii

xviii Abbreviations JFET KCL KVL LC LF LNA LO MMIC MOS MOSFET NF PCB PLL PM pp ppm Q RADAR RF RMS SAW SHF SINAD S/N SNR SPICE TC THD UHF UV VCO V/F VHF V/I VLF VSWR Junction field-effect transistor Kirchhoff s current law Kirchhoff s voltage law Inductive capacitive Low frequency Low-noise amplifier Local oscillator Monolithic microwave integrated circuit Metal-oxide semiconductor Metal-oxide semiconductor field-effect transistor Noise figure Printed circuit board Phase-locked loop Phase modulation Peak-to-peak Parts per million Quality factor Radion detecting and ranging Radio frequency Root mean square Surface acoustic wave Super high frequency Signal-to-noise plus distortion Signal to noise Signal-to-noise ratio Simulation program with integrated circuit emphasis Temperature coefficient Total harmonic distortion Ultra high frequency Ultraviolet Voltage-controlled oscillator Voltage to frequency Very high frequency Voltage current Very low frequency Voltage standing wave ratio