Summary

Using the load-pull method for RF and microwave power amplifier design

This new book on RF power amplifier design, by industry expert Dr. John F. Sevic, provides comprehensive treatment of RF PA design using the load-pull method, the most widely used and successful method of design. Intended for the newcomer to load-pull, or the seasoned expert, the book presents a systematic method of generation of load-pull contour data, and matching network design, to rapidly produce a RF PA with first-pass success. The method is suitable from HF to millimeter-wave bands, discrete or integrated, and for high-power applications. Those engaged in design or fundamental research will find this book useful, as will the student new to RF and interested in PA design.

The author presents a complete pedagogical methodology for RF PA design, starting with treatment of automated contour generation to identify optimum transistor performance with constant source power load-pull. Advanced methods of contour generation for simultaneous optimization of many variables, such as power, efficiency, and linearity are next presented. This is followed by treatment of optimum impedance identification using contour data to address specific objectives, such as optimum efficiency for a given linearity over a specific bandwidth. The final chapter presents a load-pull specific treatment of matching network design using load-pull contour data, applicable to both single-stage and multi-stage PA's. Both lumped and distributed matching network synthesis methods are described, with several worked matching network examples.

Readers will see a description of a powerful and accessible method that spans multiple RF PA disciplines, including 5G base-station and mobile applications, as well as sat-com and military applications; load-pull with CAD systems is also included. They will review information presented through a practical, hands-on perspective. The book:

Helps engineers develop systematic, accurate, and repeatable approach to RF PA design
Provides in-depth coverage of using the load-pull method for first-pass design success
Offers 150 illustrations and six case studies for greater comprehension of topics

Author Biography

John F. Sevic is Vice President of Marketing at Focus Microwaves. He has held senior design and management positions at Qualcomm, Cree, and Maury Microwave. Sevic is co-inventor of the world's most popular method of battery-life improvement for mobile phones. He has served on the IEEE Microwave Theory and Techniques Editorial Review Board, IEEE International Microwave Symposium Technical Program Committee, and IEEE Automatic RF Techniques Group TPC. He has nine US patents.

List of illustrations page vii

Acronyms, abbreviations, and notation xvi

Dedication xviii

Preface xix

References xxii

Forward xxiv

1 Historical Methods of RF Power Amplier Design 1

1.1 e RF Power Amplifier 1

1.2 History of RF Power Amplifier Design Methods 3

1.2.1 Copper Tape and the X-Acto Knife 4

1.2.2 e Shunt Stub Tuner 4

1.2.3 e Cripps Method 5

1.3 e Load-Pull Method of RF Power Amplifier Design 5

1.3.1 History of the Load-Pull Method 6

1.3.2 RF Power Amplifier Design with the Load-Pull Method 8

1.4 Historical Limitations of the Load-Pull Method 10

1.4.1 Minimum Impedance Range 10

1.4.2 Independent Harmonic Tuning 11

1.4.3 Peak and RMS Power Capability 12

1.4.4 Operating and Modulation Bandwidth 12

1.4.5 Linearity Impairment 13

1.4.6 Rigorous Error Analysis 14

1.4.7 Acoustically Induced Vibrations 15

1.5 Closing Remarks 15

References 15

2 Automated Impedance Synthesis 17

2.1 Methods of Automated Impedance Synthesis 18

2.1.1 Passive Electromechanical Impedance Synthesis 18

iv Contents

2.1.2 e Active-Loop Method of Impedance Synthesis 20

2.1.3 e Active-Injection Method of Impedance Synthesis 24

2.2 Understanding Electromechanical Tuner Performance 27

2.2.1 Impedance Synthesis Range 27

2.2.2 Operating Bandwidth 29

2.2.3 Modulation Bandwidth 31

2.2.4 Tuner Insertion Loss 32

2.2.5 Power Capability 35

2.2.6 Vector Repeatability 38

2.2.7 Impedance State Resolution and Uniformity 38

2.2.8 Factors Influencing Tuner Speed 40

2.2.9 e Slab-Line to Coaxial Transition 40

2.3 Advanced Considerations in Impedance Synthesis 41

2.3.1 Independent Harmonic Impedance Synthesis 41

2.3.2 Sub-1

Impedance Synthesis 44

2.4 Closing Remarks 47

References 47

3 Load-Pull System Architecture and Verication 49

3.1 Load-Pull System Architecture 50

3.1.1 Load-Pull System Block Diagram 50

3.1.2 Source and Load Blocks 51

3.1.3 Signal Synthesis and Analysis 57

3.1.4 Large-Signal Input Impedance Measurement 57

3.1.5 AM-AM, AM-PM and IM Phase Measurement 58

3.1.6 Dynamic Range Optimization 59

3.2 e DC Power Source 59

3.2.1 Charge Storage, Memory, and Video Bandwidth 60

3.2.2 Load-Pull of True PAE 61

3.2.3 e Effect of DC Bias Network Loss 62

3.3 e GT Method of System Verification 63

3.4 Electromechanical Tuner Calibration 65

3.5 Closing Remarks 66

References 67

4 Load-Pull Data Acquisition and Contour Generation 68

4.1 Constant Source Power Load-Pull 69

4.1.1 Load-pull with a Single Set of Contours 70

4.1.2 Load-Pull with Two or More Sets of Contours 75

4.1.3 Load-Pull for Signal Quality Optimization 78

Contents v

4.1.4 Large-Signal Input Impedance 81

4.2 Fixed-Parametric Load-Pull 82

4.2.1 Fixed Load Power 84

4.2.2 Fixed Gain Compression 86

4.2.3 Fixed Peak-Average Ratio 86

4.2.4 Fixed Signal Quality 88

4.2.5 Treating Multiple Contour Intersections 88

4.3 Harmonic Load-Pull 89

4.3.1 Second Harmonic Load-Pull 90

4.3.2 ird-Harmonic Load-Pull 92

4.3.3 Higher-Order Effects and Inter-Harmonic Coupling 92

4.3.4 Baseband Load-Pull for Video Bandwidth Optimization 93

4.4 Swept Load-Pull 93

4.4.1 Swept Available Source Power 95

4.4.2 Swept Bias 95

4.4.3 Swept Frequency 95

4.5 Advanced Techniques of Data Acquisition 96

4.5.1 Simplified Geometric-Logical Search 96

4.5.2 Synthetic Geometric-Logical Search 97

4.5.3 Multi-Dimensional Load-Pull and Data Slicing 98

4.5.4 Min-Max Peak Searching 101

4.6 Closing Remarks 102

References 103

5 Optimum Impedance Identication 104

5.1 Physical Interpretation of the Optimum Impedance 104

5.2 e Optimum Impedance Trajectory 106

5.2.1 Optimality Condition 106

5.2.2 Uniqueness Condition 107

5.2.3 Terminating Impedance 107

5.3 Graphical Extraction of the Optimum Impedance 108

5.3.1 Optimum Impedance State Extraction 108

5.3.2 Optimum Impedance Trajectory Extraction 109

5.3.3 Treatment of Orthogonal Contours 111

5.4 Optimum Impedance Extraction from Load-Pull Contours 112

5.4.1 Simultaneous Average Load Power and PAE 114

5.4.2 Simultaneous Average Load Power, PAE and Signal

Quality 114

5.4.3 OptimumImpedance ExtractionUnder Fixed-Parametric

Load-Pull 115

vi Contents

5.4.4 PAE and Signal Quality Extraction Under Constant

Average Load Power 117

5.4.5 Optimum Impedance Extraction with Bandwidth as a

Constraint 119

5.4.6 Extension to Source-Pull 119

5.4.7 Extension to Harmonic and Base-Band Load-pull 120

5.5 Closing Remarks 121

6 Matching Network Design with Load-Pull Data 123

6.1 Specification of Matching Network Performance 124

6.2 e Butterworth Impedance Matching Network 124

6.2.1 e Butterworth L-Section Prototype 125

6.2.2 Analytical Solution of the Butterworth Matching

Network 126

6.2.3 Graphical Solution of the Butterworth Matching

Network 129

6.3 Physical Implementation of the Butterworth Matching Network 129

6.3.1 e Lumped-Parameter Butterworth Matching Network 130

6.3.2 e Distributed-Parameter Butterworth Matching

Network 133

6.3.3 e Hybrid-Parameter Butterworth Matching Network 134

6.4 Supplemental Matching Network Responses 138

6.4.1 e Chebyshev Response 140

6.4.2 e Hecken and Klopfenstein Responses 141

6.4.3 e Bessel-ompson Response 144

6.5 Matching Network Loss 145

6.5.1 Definition of Matching Network Loss 145

6.5.2 e Effects of Matching Network Loss 146

6.5.3 Minimizing Matching Network Loss 146

6.6 Optimum Harmonic Termination Design 148

6.6.1 Optimally EngineeredWaveforms 148

6.6.2 Physical Implementation of Optimum Harmonic

Terminations 149

6.6.3 Optimum Harmonic Terminations in Practice 151

6.7 Closing Remarks 152

References 153

Supplemental Materials

What is included with this book?

The New copy of this book will include any supplemental materials advertised. Please check the title of the book to determine if it should include any access cards, study guides, lab manuals, CDs, etc.

The Used, Rental and eBook copies of this book are not guaranteed to include any supplemental materials. Typically, only the book itself is included. This is true even if the title states it includes any access cards, study guides, lab manuals, CDs, etc.