Radio Frequency Circuit Design

338 Pages·2001·2.68 MB·English

by  W. Alan Davis

Radio Frequency
Circuit Design
W. ALAN DAVIS
UniversityofTexasatArlington
KRISHNA AGARWAL
RaytheonSystemsCompany
AWILEY-INTERSCIENCEPUBLICATION
JOHN WILEY & SONS, INC.
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LibraryofCongressCataloging-in-PublicationData:
Davis,W.Alan.
Radiofrequencycircuitdesign/W.AlanDavis,KrishnaAgarwal.
p.cm.—(Wileyseriesinmicrowaveandopticalengineering)
Includesindex.
ISBN0-471-35052-4
1.Radiocircuits—Designandconstruction.I.Agarwal,KrishnaK.(KrishnaKumar)
II.Title.III.Series.
TK6560.D382001
621.381’32—dc21 00-043690
PrintedintheUnitedStatesofAmerica.
10987654321
Dedicatedtoourwives,
MargaretDavis,ElisabethAgarwal
andourchildren:
Brent,Nathan,JanelleDavis
Sareeta,Sandeep,SuneetAgarwal
Contents
Preface xiii
1 Communication Channel 1
1.1 Basic Transmitter–Receiver Configuration 1
1.2 Information and Capacity 3
1.3 Dependent States 6
Problems 8
References 8
2 Resistors, Capacitors, and Inductors 9
2.1 Introduction 9
2.2 Resistors 9
2.3 Capacitors 14
2.4 Inductors 20
Problems 31
References 31
3 Impedance Matching 33
3.1 Introduction 33
3.2 The Q Factor 33
3.3 Resonance and Bandwidth 34
3.4 Unloaded Q 36
3.5 L Circuit Impedance Matching 36
3.6 (cid:3) Transformation Circuit 39
3.7 T Transformation Circuit 41
3.8 Tapped Capacitor Transformer 42
3.9 Parallel Double-Tuned Transformer 45
Problems 49
References 50
vii
4 Multiport Circuit Parameters and Transmission Lines 51
4.1 Voltage–Current Two-Port Parameters 51
4.2 ABCD Parameters 53
4.3 Image Impedance 54
4.4 The Telegrapher’s Equations 59
4.5 The Transmission Line Equation 61
4.6 The Smith Chart 63
4.7 Commonly Used Transmission Lines 65
4.8 Scattering Parameters 74
4.9 The Indefinite Admittance Matrix 78
4.10 The Indefinite Scattering Matrix 80
Problems 82
References 82
5 Filter Design and Approximation 84
5.1 Introduction 84
5.2 Ideal and Approximate Filter Types 84
5.3 Transfer Function and Basic Filter Concepts 88
5.4 Ladder Network Filters 89
5.5 The Elliptic Filter 94
5.6 Matching between Unequal Resistances 95
Problems 104
References 104
6 Transmission Line Transformers 105
6.1 Introduction 105
6.2 Ideal Transmission Line Transformers 106
6.3 Transmission Line Transformer Synthesis 110
6.4 Electrically Long Transmission Line Transformers 111
6.5 Baluns 115
6.6 Dividers And Combiners 117
Problems 121
References 121
7 Class A Amplifiers 122
7.1 Introduction 122
7.2 Definition of Gain [2] 122
7.3 Transducer Power Gain of a Two-Port 123
7.4 Power Gain Using S Parameters 124
7.5 Simultaneous Match for Maximum Power Gain 127
7.6 Stability 129
7.7 Class A Power Amplifiers 139
7.8 Power Combining of Power Amplifiers 141
Problems 142
References 143
8 Noise 144
8.1 Sources of Noise 144
8.2 Thermal Noise 145
8.3 Shot Noise 148
8.4 Noise Circuit Analysis 149
8.5 Amplifier Noise Characterization 151
8.6 Noise Measurement 152
8.7 Noisy Two-Ports 153
8.8 Two-Port Noise Figure Derivation 154
8.9 The Fukui Noise Model for Transistors 158
8.10 Properties of Cascaded Amplifiers 161
8.11 Amplifier Design for Optimum Gain and Noise 164
Problems 166
References 166
9 RF Power Amplifiers 168
9.1 Transistor Configurations 168
9.2 The Class B Amplifier 169
9.3 The Class C Amplifier 178
9.4 Class C Input Bias Voltage 183
9.5 The Class D Power Amplifier 184
9.6 The Class F Power Amplifier 185
9.7 Feed-Forward Amplifiers 191
Problems 193
References 193
10 Oscillators and Harmonic Generators 195
10.1 Oscillator Fundamentals 195
10.2 Feedback Theory 197
10.3 Two-Port Oscillators with External Feedback 197
10.4 Practical Oscillator Example 202
10.5 Minimum Requirements of the Reflection Coefficient 204
10.6 Common Gate (Base) Oscillators 206
10.7 Stability of an Oscillator 210
10.8 Injection-Locked Oscillators 214
10.9 Harmonic Generators 216
Problems 221
References 221
11 RF Mixers 222
11.1 Nonlinear Device Characteristics 222
11.2 Figures of Merit for Mixers 226
11.3 Single-Ended Mixers 227
11.4 Single-Balanced Mixers 228
11.5 Double-Balanced Mixers 230
11.6 Double-Balanced Transistor Mixers 235
11.7 Spurious Response 240
11.8 Single-Sideband Noise Figure and Noise Temperature 243
Problems 246
References 246
12 Phase Lock Loops 247
12.1 Introduction 247
12.2 PLL Design Background 247
12.3 PLL Applications 248
12.4 PLL Basics 249
12.5 Loop Design Principles 250
12.6 PLL Components 251
12.7 Linear Analysis of the PLL [1] 255
12.8 Locking a Phase Lock Loop 259
12.9 Loop Types 261
12.10 Negative Feedback in a PLL 263
12.11 PLL Design Equations 264
12.12 PLL Oscillators 270
12.13 Phase Detector Types 271
12.14 Design Examples 274
Problems 277
References 277
13 Emerging Technology 278
13.1 Introduction 278
13.2 Bandwidth 280
13.3 Spectrum Conservation 280
13.4 Mobility 281
13.5 Wireless Internet Access 282
13.6 Key Technologies 283
References 284
Appendixes
A. Example of a Solenoid Design 285
B. Analytical Spiral Inductor Model 286
C. Double-Tuned Matching Circuit Example 290
D. Two-Port Parameter Conversion 292
E. Termination of a Transistor Port with a Load 296
F. Transistor and Amplifier Formulas 300
G. Transformed Frequency Domain Measurements
Using Spice 305
H. Single-Tone Intermodulation Distortion
Suppression for Double-Balanced Mixers 319
Index 323
Preface
The cellular telephone has become a symbol for the rapidchange in the commu-
nications business. Within this plastic container reside the talents of engineers
working in the areas of efficient power supplies, digital circuit design, analog
circuit design, semiconductor device design, antennas, linear systems, digital
signalprocessing,packaging,andmaterialsscience.Allthesetalentsarecarefully
coordinatedatacostthatallowsawidecrosssectionoftheworld’spopulationto
haveavailableinstantcommunication.Theparticularaspectofalltheseactivities
that is of primary focus in this text is in the area of analog circuit design, with
primary emphasis on radio frequency electronics. Some topics normally consid-
ered in electronics courses or in microwave and antenna courses are not covered
here. For example, there is no mention of distributed branch line couplers, since
at1GHztheirsizewouldbeprohibitive.Ontheotherhand,topicssuchastrans-
missionlinetransformersarecoveredbecausetheyfitsowellintothisfrequency
range.
This book is meant for readers who have at least advanced standing in elec-
trical engineering. The material in this text has been taught as a senior and
graduate-levelcourseinradiofrequencycircuitdesignattheUniversityofTexas
at Arlington. This class has continued to be popular for the past 20 years under
the guidance of at least four different instructors, two of whom are the present
authors. Because of the activity in the communications area, there has been ever
greater interest in this subject. It is the intent of the authors, therefore, to update
the current text offerings while at the same time avoiding simply reworking a
microwave text.
The authors gratefully acknowledge the contribution of Michael Black,
Raytheon Systems Company, to the phase lock loop discussion in Chapter 12.
W. Alan Davis
Krishna Agarwal
RadioFrequencyCircuitDesign.W.AlanDavis,KrishnaAgarwal
Copyright2001JohnWiley&Sons,Inc.
PrintISBN0-471-35052-4ElectronicISBN0-471-20068-9
CHAPTERONE
Communication Channel
1.1 BASICTRANSMITTER–RECEIVERCONFIGURATION
The design of radio frequency (RF) circuits borrows from methods used in low-
frequency audio circuits as well as from methods used in design of microwave
circuits. Yet there are also important departures from these techniques, so the
designofradiofrequencycircuitsrequiressomespecializedtechniquesnotfound
in these other frequency ranges. The radio frequency range for present purposes
willbetakentobesomewherebetween300 MHzand3 GHz.Itisthisfrequency
range where much of the present day activity in wireless communication occurs.
In this range of frequencies, the engineer must be concerned about radiation,
stray coupling, and frequency response of circuit elements that from the point
of view of lumped, low-frequency analysis might be expected to be indepen-
dent of frequency. At the same time the use of common microwave circuit
elements such as quarter wave transformers is impractical because of the long
line lengths required. The use of monolithic circuits have enabled many high-
frequency designs to be implemented with lumped elements, yet the frequency
response of these “lumped” elements still must be carefully considered.
Today RF and digital designs have begun to move closer together, so typical
communicationsystemsincorporatebothofthesedisciplinesintheirdesign.While
directdigitizingofRFsignalsremainsachallenge,therearemanysystemswhere
digitalsignalprocessingisplayingalargerrolethaneverincommunicationsystems.
AtypicalradioanalogtransmitterandreceiverisshowninFig.1.1.Inthissystem
theinformationsourcecouldbeanaudioorvideosignal.Thisinformationinthe
processofbeingconvertedfrom,say,soundtoanelectricalsignalbyatransducer
producesaverylowvoltagethatmustbeamplifiedbyanaudioamplifier.
The modulator is shown schematically as a mixer that represents a wide
variety of different modulation schemes. The two major categories are analog
anddigitalmodulation. Ineithercasethemodulator performstwofunctions.The
first function is that it encodes the message in a certain way so as to meet the
communication channel requirements for cost, noise immunity, fading, available
1