LINEARIZATION TECHNIQUES FOR INTEGRATED CMOS POWER AMPLIFIERS

140 Pages·2007·1.28 MB·English

LINEARIZATION TECHNIQUES FOR INTEGRATED CMOS POWER AMPLIFIERS AND
A HIGH EFFICIENCY CLASS-F GaN POWER AMPLIFIER

By

SANGWON KO

A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY

UNIVERSITY OF FLORIDA

2007
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© 2007 Sangwon Ko

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To my parents

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ACKNOWLEDGMENTS
I would like to thank the chair of my committee members, Professor Jenshan Lin. He
guided and supported me during my Ph.D program. I also appreciate the other committee
members, Professor William R. Eisenstadt, Professor Bashirullah, and Professor Fan Ren for
their interest in this work and expert assistance.
Specially, I would like to express my appreciation to Professor William R. Eisenstadt for
his guidance and support. I am also grateful to Professor Fan Ren for his encouragement.
Finally, I cannot express how grateful I am to my parents for their unceasing love and
dedication. Most importantly, I thank God for caring for me throughout my life.

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TABLE OF CONTENTS

page
ACKNOWLEDGMENTS...............................................................................................................4
LIST OF TABLES...........................................................................................................................8
LIST OF FIGURES.........................................................................................................................9
ABSTRACT...................................................................................................................................13
CHAPTER
1 INTRODUCTION..................................................................................................................15
1.1 Motivation and Research Objective..................................................................................15
1.1.1 High Linearity Power Amplifier............................................................................15
1.1.2 Power Amplifier using CMOS Process..................................................................16
1.1.3 High Efficiency Power Amplifier using Wide Bandgap Device............................18
1.2 Organization.....................................................................................................................21
2 OVERVIEW OF APPLICATIONS AND THEORY OF POWER AMPLIFER...................23
2.1 Applications of Mobile Wireless Communications..........................................................23
2.1.1 Wireless Local Area Networks (WLANs).............................................................23
2.1.2 Bluetooth................................................................................................................24
2.1.3 Wireless Mobile Phones.........................................................................................25
2.2 Transmitter and RF Power Amplifier...............................................................................26
2.3 Transmitter Topologies.....................................................................................................27
2.3.1 Direct Digital Synthesis Transmitter......................................................................28
2.3.2 Direct Conversion Transmitter...............................................................................29
2.3.3 Heterodyne Transmitter..........................................................................................30
2.4 Power Amplifier Performance Parameters.......................................................................31
2.4.1 1 dB Gain Compression Point................................................................................31
2.4.2 Third Order Intercept Point (IIP3)..........................................................................33
2.4.3 Overall IIP3 of Cascaded Nonlinear Stages...........................................................36
2.4.4 Intermodulation Distortion and Adjacent Channel Power Ratio............................39
2.4.5 Drain Efficiency and Power Added Efficiency......................................................40
3 LINEARIZATION TECHNIQUES FOR POWER AMPLIFIERS.......................................42
3.1 Background of Linearization Techniques.........................................................................42
3.2 Power Back-off.................................................................................................................43
3.3 Feedback...........................................................................................................................43
3.3.1 Direct Feedback......................................................................................................44
3.3.2 Envelope Elimination and Restoration Transmitter with Feedback.......................45
3.3.3 Polar Transmitter with Feedback............................................................................46
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3.3.4 Cartesian Feedback.................................................................................................48
3.4 Predistortion......................................................................................................................51
3.4.1 Analog Type Predistorter.......................................................................................53
3.4.2 Digital Type Predistorter........................................................................................55
3.5 Feedforward......................................................................................................................56
4 PREDISTORTER USING DIODE-CONNECTED MOSFET..............................................58
4.1 Background.......................................................................................................................58
4.2 Basic Configuration of the Predistorter............................................................................58
4.3 Voltage and Current Swing through FET and Equivalent Elements................................59
4.4 Large Signal S21 of the Predistorter.................................................................................62
4.5 Phase Characteristic of the Predistorter............................................................................63
4.6 CMOS Power Amplifier with the Predistorter.................................................................65
4.7 Experimental Results........................................................................................................67
5 LINEARIZATION OF CASCODE CMOS POWER AMPLIFIER......................................74
5.1 Background.......................................................................................................................74
5.2 Control of Phase Characteristic of the Predistorter..........................................................75
5.3 Cascode CMOS Power Amplifier with the Predistorter...................................................77
5.4 Linearization Performance................................................................................................78
5.5 Experimental Results........................................................................................................80
6 PREDISTORTER USING MOSFET IN NEAR-COLD FET CONDITION........................86
6.1 Background.......................................................................................................................86
6.2 Basic Configuration of the Predistorter............................................................................87
6.3 Voltage and Current Swing through FET and Equivalent Elements................................88
6.4 Large Signal S21 of the Predistorter.................................................................................91
6.5 Phase Characteristic of the Predistorter............................................................................92
6.6 CMOS Power Amplifier with the Predistorter.................................................................93
6.7 Experimental Results........................................................................................................96
7 COMPARISON AMONG PREDISTORTERS AND STATE OF ART CMOS
PREDISTORTERS...............................................................................................................101
7.1 Comparison between Developed Predistorters...............................................................101
7.1.1 Comparison between Predistorter using the Diode-Connected MOSFET and
Predistorter using the Schottky Diode.......................................................................101
7.1.2 Comparison between Predistorter using MOSFET in Near-Cold FET
Condition and Predistorter using the Diode-Connected MOSFET............................101
7.2 Integrated RF and IF Predistorters..................................................................................102
7.2.1 State of Art IF Predistorter...................................................................................102
7.2.2 State of Art RF Predistorter..................................................................................102
7.2.3 Bias Stabilization using Active Bias Circuit........................................................103
8 HIGH EFFICIENCY POWER AMPLIFIERS.....................................................................105
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8.1 Background.....................................................................................................................105
8.2 Class A and Class B Power Amplifier............................................................................106
8.3 Class C Power Amplifier................................................................................................108
8.4 Class D Power Amplifier................................................................................................109
8.5 Class E Power Amplifier................................................................................................110
8.6 Class F Power Amplifier................................................................................................113
9 A HIGH EFFICIENCY CLASS-F POWER AMPLIFIER USING A GA-N DEVICE......117
9.1 Background.....................................................................................................................117
9.2 Modeling of GaN Device................................................................................................117
9.3 Design of Class-F Power Amplifier...............................................................................120
9.4 Fabrication and Measurement.........................................................................................124
10 SUMMARY AND FUTURE WORK..................................................................................128
10.1 Summary and Conclusion.............................................................................................128
10.1.1 Summary on Linearization of CMOS Power Amplifier.....................................128
10.1.2 Summary on High Efficiency GaN Power Amplifier........................................130
10.2 Implication for Future Work.........................................................................................131
10.2.1 Implication for Future Work on Linearization of CMOS Power Amplifier......131
10.2.2 Implication for Future Work on High Efficiency GaN Power Amplifier..........131
LIST OF REFERENCES.............................................................................................................133
BIOGRAPHICAL SKETCH.......................................................................................................140

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LIST OF TABLES
Table page

1-1 Characteristics comparison of technologies...........................................................................18
1-2 Properties of Si, GaAs, SiC, and GaN....................................................................................20
2-1 Properties of popular 802.11 standards..................................................................................24
2-2 Classes of Bluetooth standards...............................................................................................25
5-1 Input and output scattering parameters...................................................................................84
8-1 Classification of amplifiers...................................................................................................109
10-1 Measurement results of fabricated power amplifiers.........................................................129
10-2 Integrated RF and IF linearization circuits.........................................................................130

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LIST OF FIGURES
Figure page

2-1 Configuration of a transmitter...............................................................................................27
2-2 A direct digital synthesis transmitter.....................................................................................28
2-3 A direct conversion transmitter.............................................................................................29
2-4 A heterodyne transmitter.......................................................................................................30
2-5 Gain compression of a power amplifier................................................................................32
2-6 Output spectrum of a power amplifier with two tone input signal........................................33
2-7 Third order intercept point of a power amplifier...................................................................34
2-8 Cascade of three nonlinear blocks.........................................................................................36
3-1 Multi-channel approach with several single channel power amplifiers................................42
3-2 Feedback system applied to an amplifier..............................................................................44
3-3 Series feedback and parallel feedback...................................................................................45
3-4 An envelope feedback system...............................................................................................46
3-5 A polar feedback system........................................................................................................47
3-6 A modulated signal on Cartesian coordinates.......................................................................49
3-7 A Cartesian feedback.............................................................................................................50
3-8 Gain characteristics of a power amplifier with a predistorter...............................................51
3-9 A cubic type RF predistorter.................................................................................................54
3-10 A simple type RF predistorter.............................................................................................55
3-11 Feedforward system.............................................................................................................56
4-1 Basic configuration of predistorter........................................................................................59
4-2 Dynamic impedance line of predistorter...............................................................................59
4-3 Voltage and current waveforms of predistorter.....................................................................60
4-4 Impedance of predistorter on Smith chart.............................................................................60
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4-5 Equivalent R and C of predistorter....................................................................................61
V V
4-6 Gain and phase of the predistorter.........................................................................................63
4-7 Predistorter with an additional parallel capacitor..................................................................64
4-8 Phase variation of predistorter for four different values of C ..............................................64
P
4-9 CMOS power amplifier with predistorter..............................................................................65
4-10 Relative gain and phase of the power amplifier..................................................................66
4-11 IMD3 characteristic of the power amplifier........................................................................66
4-12 Power amplifier with predistorter........................................................................................67
4-13 Measured scattering parameters..........................................................................................68
4-14 Measured output power, gain, and PAE..............................................................................68
4-15 Two tone measurement setup..............................................................................................69
4-16 Arrangement of measurement equipments..........................................................................70
4-17 Measured IMD3 characteristic with low bias voltage for the predistorter..........................71
4-18 Simulated IMD3 characteristic with low bias voltage for the predistorter..........................71
4-19 Measured IMD3 characteristic of the high bias voltage for the predistorter.......................72
4-20 Simulated IMD3 characteristic of the high bias voltage for the predistorter......................72
5-1 Gain and phase characteristics of cascode power amplifier with predistorter......................74
5-2 Predistorter having positive AM-PM characteristic..............................................................75
5-3 Gain and phase of the predistorter with parallel inductor.....................................................76
5-4 S21 of the predistorter...........................................................................................................77
5-5 Schematic diagram of the power amplifier............................................................................78
5-6 Relative gain and phase of the power amplifier.....................................................................79
5-7 IMD3 characteristic of the power amplifier...........................................................................79
5-8 Power amplifier with predistorter..........................................................................................80
5-9 Measured scattering parameters............................................................................................81
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