本論文主要內容為設計並實現兩個使用互補式金氧半場效電晶體製程的2.4GHz功率放大器，第一個放大器採用了自適應性偏壓的控制電路，第二個則是採用變壓器進行功率結合。
論文的第一部份分為兩章，第一章首先介紹現今的無線通訊系統和其規範，第二章則是介紹功率放大器的基礎架構和電路特性。論文的第二部份為所設計兩顆功率放大器的模擬及量測結果。
在第三章裡所介紹的第一顆功率放大器是使用自適應性偏壓控制以提高在後退操作時的效率，此放大器採用零點一八微米互補式金氧半場效電晶體製程，其偏壓控製電路在偵測並放大輸入訊號後會自動的控制輸出級電晶體的偏壓。本功率放大器的量測結果為增益14dB，在1dB點時輸出功率為21.2dBm，PAE為27.4%。而在6dB退後操作時， PAE為10.6%。
而在第四章所介紹的第二顆功率放大器則是使用變壓功率結合器進行功率結合以達成高輸出的功率放大器，此放大器採用兩組放大器對並透過一對二的變壓結合器將功率合成後再做輸出。製程同樣採用零點一八微米的互補式金氧半場效電晶體製程，操作頻率為2.4GHz。此放大器量測後所得到的增益為20dB，在1dB壓縮點時，輸出功率為24dBm，PAE為10%，當到達飽和輸出時，輸出功率為26.1dBm，其PAE為14.7%，最後則討論了量測結果不如理想的可能原因並提出解決辦法。

The main subject of this thesis is to design and implement two CMOS 2.4GHz power amplifier. The first one is the adaptive bias power amplifier, and the second one is the transformer combined power amplifier.
The first part of the thesis is composed of two chapters. Chapter one introduces the modern wireless communication systems and their specification. Chapter two is discussion about the fundamentals of the power amplifier. The second part of the thesis presents the design and implementation of the proposed power amplifiers.
In chapter three, the first power amplifier is presented. It uses adaptive bias control circuit to improve the efficiency in the power back-off region. The measured gain is 14dB, and output power of P1dB point is 21.2dBm with 27.4% PAE. Finally, the PAE at 6dB back-off is 10.6%.
In chapter four, the transformer combining is introduced and used for designing a high output power amplifier. The proposed power amplifier uses a two-way power combiner to achieve high output level. The measured gain of the transformer combined power amplifier is 20dB, and output power at P1dB point is 24dBm with 10% PAE. At the saturation point, the output power and PAE are 26.1dBm and 14.7%, respectively.

Table of Contents

ACKNOWLEDGEMENTS I
ABSTRACT III
TABLE OF CONTENTS V
LIST OF FIGURES VIII
LIST OF TABLES XIII

CHAPTER 1
INTRODUCTION 1
1.1 Wireless Communication Systems 1
1.2 The RF Front End for Mobile Devices 3
1.3 Thesis Objectives and Organization 5

CHAPTER 2
FUNDAMENTALS OF POWER AMPLIFIER 7
2.1 Power Amplifier Classification 7
2.2 Load-Line Theory & Load-Pull Contour 10
2.3 Linearity Analysis 14
2.3.1 Voltage Transfer Curve 14
2.3.2 Single-Tone Analysis (AM-AM Effect) 16
2.3.3 Two-Tone Analysis: By Trigonometry 18
2.3.4 Two-Tone Analysis: By Envelope 21
2.3.5 AM-PM Effect 24
2.3.6 Behavior Model and Envelope Analysis 25
2.3.7 Predistortion 28


2.4 Power Amplifier Efficiency 30
2.4.1 Efficiency Analysis 30
2.4.2 IV characteristic of BJT and MOS 31
2.4.2 LC Matching Efficiency 32
2.5 Stability Consideration 35

CHAPTER 3
POWER AMPLIFIER WITH ADAPTIVE BIAS 37
3.1 Power Back-Off (PBO) and PAPR 37
3.2 Adaptive Bias Principle 41
3.3 Circuit Design and Simulation 43
3.4 Measurement Results and Discussion 54

CHAPTER 4
POWER AMPLIFIER WITH TRANSFORMER COMBINER 61
4.1 Introduction 61
4.2 Transformer Combiner Design 64
4.2.1 Inductor physical model 64
4.2.2 Transformer Combiner Circuit Model 66
4.3 EM Simulation for Transformer Combiner 72
4.4 Circuit Design & Simulation 76
4.5 Measurement Results and Discussion 80

CHAPTER 5
CONCLUSION AND FUTURE WORK 89



APPENDIX A
EQUATIONS FOR TRANSFORMER COMBINER 91

APPENDIX B
TRANSFORMER MODELS 94

REFERENCE 98

[1]Bluetooth Official Site, https://www.bluetooth.org/
[2]Wi-Fi Alliance, http://www.wi-fi.org/
[3]WiMAX Forum, http://www.wimaxforum.org/membership
[4]3GPP Official Site, http://www.3gpp.org/
[5]S. C. Cripps, "A theory for the prediction of GaAs FET load-pull power contours," in Microwave Symposium Digest, 1983 IEEE MTT-S International, 1983, pp. 221-223.
[6]Steve C. Cripps, RF power amplifiers for wireless communications, Artech House, 1999.
[7]B. Razavi, RF microelectronics, Prentice Hall Inc, 1998.
[8]Steve C. Cripps, Advanced techniques in RF power amplifier design, Artech House, 2002.
[9]C. D. Presti, F. Carrara, A. Scuderi, P. M. Asbeck, and G. Palmisano, "A 25 dBm digitally modulated CMOS power amplifier for WCDMA/EDGE/OFDM with adaptive digital predistortion and efficient power control," Solid-State Circuits, IEEE Journal of, vol. 44, pp. 1883-1896, 2009.
[10]S. Leuschner, J.-E. Müller, and H. Klar, "A 1.8 GHz wide-band stacked-cascode CMOS power amplifier for WCDMA applications in 65nm standard CMOS," in Radio Frequency Integrated Circuits Symposium, 2011 IEEE, 2011, pp. 1-4.
[11]Y. Li, J. Lopez, R. Wu, and D. Y. Lie, "A fully monolithic BiCMOS envelope-tracking power amplifier with on-chip transformer for broadband wireless applications," Microwave and Wireless Components Letters, IEEE, vol. 22, pp. 288-290, 2012.
[12]R. Groves, J. Malinowski, R. Volant, and D. Jadus, "High Q inductors in a SiGe BiMOS process utilizing a thick metal process add-on module," in Bipolar/BiCMOS Circuits and Technology Meeting, 1999. Proceedings of the 1999, 1999, pp. 149-152.
[13]J. Fritzin, "CMOS RF Power Amplifiers for Wireless Communications," Linköping Studies in Science and Technology.
[14]Y. Sun, Wireless Communications Circuits and Systems, IET, 2004.
[15]G. Gonzalez, Microwave transistor amplifiers : analysis and design, 2nd ed., Prentice Hall, 1997.
[16]"Measurement Expressions," Agilent ADS2009 Documentation.
[17]Wikipedia: Spectral efficiency, http://en.wikipedia.org/wiki/Spectral efficiency
[18]"802.11 Design Template " Agilent ADS2009.
[19]Y. Eo and K. Lee, "High efficiency 5GHz CMOS power amplifier with adaptive bias control circuit," in Radio Frequency Integrated Circuits (RFIC) Symposium, 2004. Digest of Papers. 2004 IEEE, 2004, pp. 575-578.
[20]Y.-J. Chen, C.-Y. Liu, T.-N. Luo, and D. Heo, "A high-efficient CMOS RF power amplifier with automatic adaptive bias control," Microwave and Wireless Components Letters, IEEE, vol. 16, pp. 615-617, 2006.
[21]蔡宗錞, "K頻段互補式金氧半導體功率放大器之自動調整偏壓技術研究," 碩士論文 國立臺灣大學電信工程學研究所, 2011.
[22]T. Hirayama, Y. Suzuki, N. Matsuno, and H. Hida, "Effect of gain expansion on power HBTs," in Microwave Conference, 2000. 30th European, 2000, pp. 1-4.
[23]I. Aoki, S. Kee, R. Magoon, R. Aparicio, F. Bohn, J. Zachan, et al., "A fully-integrated quad-band GSM/GPRS CMOS power amplifier," Solid-State Circuits, IEEE Journal of, vol. 43, pp. 2747-2758, 2008.
[24]I. Aoki, S. D. Kee, D. B. Rutledge, and A. Hajimiri, "Fully integrated CMOS power amplifier design using the distributed active-transformer architecture," Solid-State Circuits, IEEE Journal of, vol. 37, pp. 371-383, 2002.
[25]I. Aoki, S. D. Kee, D. Rutledge, and A. Hajimiri, "A 2.4-GHz, 2.2-W, 2-V fully-integrated CMOS circular-geometry active-transformer power amplifier," in Custom Integrated Circuits, 2001, IEEE Conference on., 2001, pp. 57-60.
[26]I. Aoki, S. Kee, D. Rutledge, and A. Hajimiri, "A fully-integrated 1.8-V, 2.8-W, 1.9-GHz, CMOS power amplifier," in Radio Frequency Integrated Circuits (RFIC) Symposium, 2003 IEEE, 2003, pp. 199-202.
[27]I. Aoki, S. D. Kee, D. B. Rutledge, and A. Hajimiri, "Distributed active transformer -a new power-combining and impedance-transformation technique," Microwave Theory and Techniques, IEEE Transactions on, vol. 50, pp. 316-331, 2002.
[28]P. Haldi, D. Chowdhury, P. Reynaert, G. Liu, and A. M. Niknejad, "A 5.8 GHz 1 V linear power amplifier using a novel on-chip transformer power combiner in standard 90 nm CMOS," Solid-State Circuits, IEEE Journal of, vol. 43, pp. 1054-1063, 2008.
[29]D. Chowdhury, C. D. Hull, O. B. Degani, Y. Wang, and A. M. Niknejad, "A fully integrated dual-mode highly linear 2.4 GHz CMOS power amplifier for 4G WiMax applications," Solid-State Circuits, IEEE Journal of, vol. 44, pp. 3393-3402, 2009.
[30]G. Liu, P. Haldi, T.-J. K. Liu, and A. M. Niknejad, "Fully integrated CMOS power amplifier with efficiency enhancement at power back-off," Solid-State Circuits, IEEE Journal of, vol. 43, pp. 600-609, 2008.
[31]J. Kim, W. Kim, H. Jeon, Y.-Y. Huang, Y. Yoon, H. Kim, et al., "A fully-integrated high-power linear CMOS power amplifier with a parallel-series combining transformer," Solid-State Circuits, IEEE Journal of, vol. 47, pp. 599-614, 2012.
[32]E. Kaymaksut and P. Reynaert, "Transformer-based uneven Doherty power amplifier in 90 nm CMOS for WLAN applications," Solid-State Circuits, IEEE Journal of, vol. 47, pp. 1659-1671, 2012.
[33]D. Chowdhury, P. Reynaert, and A. M. Niknejad, "Transformer-coupled power amplifier stability and power back-off analysis," Circuits and Systems II: Express Briefs, IEEE Transactions on, vol. 55, pp. 507-511, 2008.
[34]A. Afsahi and L. E. Larson, "An integrated 33.5 dBm linear 2.4 GHz power amplifier in 65nm CMOS for WLAN applications," in Custom Integrated Circuits Conference (CICC), 2010 IEEE, 2010, pp. 1-4.
[35]J. Javidan, M. Atarodi, and H. C. Luong, "High power amplifier based on a transformer-type power combiner in CMOS technology," Circuits and Systems II: Express Briefs, IEEE Transactions on, vol. 57, pp. 838-842, 2010.
[36]K. H. An, O. Lee, H. Kim, D. H. Lee, J. Han, K. S. Yang, et al., "Power-combining transformer techniques for fully-integrated CMOS power amplifiers," Solid-State Circuits, IEEE Journal of, vol. 43, pp. 1064-1075, 2008.
[37]W. Tai, H. Xu, A. Ravi, H. Lakdawala, O. B. Degani, L. R. Carley, et al., "A 31.5 dBm outphasing class-D power amplifier in 45nm CMOS with back-off efficiency enhancement by dynamic power control," in ESSCIRC (ESSCIRC), 2011 Proceedings of the, 2011, pp. 131-134.
[38]呂紹良, "微波存取全球互通頻段變壓器耦合式功率放大器與電壓控制振盪器暨除頻器之研製," 碩士論文 國立中央大學電機工程研究所, 2008.
[39]Sanguine-Microelectronics, "到底改了甚麼? 新一代CMOS PA AX508與AX502的比較," 2008.
[40]A. B. Carlson, Circuits: engineering concepts and analysis of linear electric circuits, Brooks/ Cole, 2000.