Design of Linear RF Outphasing Power Amplifiers

214 Pages·2003·6.01 MB·English

by  Xuejun Zhang

Design of Linear RF Outphasing
Power Amplifiers
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Design of Linear RF Outphasing
Power Amplifiers
Xuejun Zhang
Lawrence E. Larson
Peter M. Asbeck
Artech House
Boston London
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www.artechhouse.com
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Zhang,Xuejun
DesignoflinearRFoutphasingpoweramplifiers.—(ArtechHousemicrowave
library)
1.Poweramplifiers—Design 2.Amplifiers,Radiofrequency—Design
I.Title II.Larson,LawrenceE. III.Asbeck,Peter
621.3’8412
ISBN1-58053-374-4
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q2003ARTECHHOUSE,INC.
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10 9 8 7 6 5 4 3 2 1
To my wife Huijuan—always part of what I do
— X. Zhang
To the memory of my late father, Clarence Edward Larson
— L. E. Larson
To my wife, Marcia, and my children, Alan and Lynn
— P. M. Asbeck

Contents
Preface xi
1 Introduction 1
1.1 The Role of Power Amplifiers in
Wireless Communication Systems 1
1.2 Characterization of Power Amplifiers
for Wireless Communications 4
1.2.1 Power Amplifier Waveform Quality
Measurements 6
1.2.2 Power Efficiency Measurements 19
1.3 Power Amplifier Linearization and
Efficiency-Enhancement Techniques 22
1.4 Outphasing Microwave Power Amplifiers 27
1.4.1 Historical Perspectives on Outphasing
Power Amplifiers 27
1.4.2 Introduction to the Theory of
Outphasing Amplification 29
References 32
2 Linearity Performance of Outphasing
Power Amplifier Systems 35
2.1 Introduction 35
2.2 Digital Modulation Techniques 36
2.2.1 QPSK and Its Variations 36
2.2.2 QAM 41
vii
viii DesignofLinearRF OutphasingPowerAmplifiers
2.3 Baseband Filtering of Digital Data 41
2.3.1 Raised Cosine Filter 45
2.3.2 Gaussian Filter 49
2.3.3 IS-95 Baseband Filter 50
2.4 Signal Component Separation for
Outphasing Amplifiers 51
2.5 Path Imbalance and Its Effects on Linearity 61
2.5.1 Two-Tone Linearity Analysis of an
Outphased Amplifier with
Path Mismatch Effects 62
2.5.2 ACI Estimation with Gain and
Phase Mismatch 64
2.6 Effect of Quadrature Modulator Errors
on Linearity 67
2.6.1 Quadrature Modulator Error
Minimization 69
2.6.2 Quadrature Modulator Error Effects
on Outphasing Systems 72
2.7 SCS Quantization Error Effects
on Outphasing Systems 75
2.7.1 Error Effects of Quantization of
the Source Signal 75
2.7.2 Error Effects of Quantization of
the Quadrature Signal 76
2.8 Linearity Effects of Reconstruction Filter
and DSP Sampling Rate 79
2.9 Summary 81
References 83
3 Path Mismatch Reduction Techniques
for Outphasing Amplifiers 87
3.1 Introduction 87
3.2 Correction Schemes Based on
Training Vectors 88
Contents ix
3.2.1 Baseband Preconditioning of
Path Mismatch Errors 89
3.2.2 Foreground Calibration Algorithm of
Path Mismatch Errors 91
3.3 Path Mismatch Error Correction
Schemes Transparent to Data Transmission 101
3.3.1 Phase-Only Correction Approach 101
3.3.2 Simplex Search Algorithm Correction 102
3.3.3 Direct Search Algorithm 104
3.3.4 Background Calibration Algorithm 105
3.4 Mismatch Correction Scheme for
Broadband Applications 112
3.5 VCO-Derived Synthesis 114
3.5.1 CALLUM 119
3.5.2 VLL 124
References 126
4 Power-Combining and
Efficiency-Enhancement Techniques 129
4.1 Introduction 129
4.2 Power-Combining Techniques for
Outphasing Amplifiers 130
4.3 Amplifier Choices for Outphasing Systems 135
4.4 Outphasing Amplifier Design Using
Class A, B, and C Amplifiers 137
4.5 Chireix Power-Combining Technique 142
4.6 Combiner Design for Switching-Mode
(Class D and Class E) Amplifiers 145
4.6.1 Analysis of MOSFET-Based Class D
Outphasing Amplifier with Lossless
Combining 147
4.6.2 Simulation and Discussion of
MOS-Based Class D with Lossless
Combining 153