Advanced design features of Doherty power amplifiers

A Doherty power amplifier (DPA) is an effective structure born in 1936 which, after a scarce revival around year 2000), had been strengthened from 2005 because its capability to combine linear amplification with power efficiency. Despite the conceptual simplicity of its basic operation, a lot of practical drawbacks shrink the theoretical behavior, thus leading a significant number of research works to overcome them. The main objective in DPA research is to increase efficiency while maintaining linearity and filling the specified bandwidth. This paper presents a survey of the state of the art of DPA advanced design aspects. After a short review of the DPA operation principles, aspects regarding improvements for linearity, power efficiency and amplification bandwidth are introduced. Besides, some alternative structures and technologies, as well as practical design aspects and some trade-offs which the designer usually has to face are also presented.

[1]  Jeng-Han Tsai,et al.  A 38–46 GHz MMIC Doherty Power Amplifier Using Post-Distortion Linearization , 2007, IEEE Microwave and Wireless Components Letters.

[2]  Franco Giannini,et al.  The Doherty amplifier and its evolution for modern communication systems , 2011, 2011 MICROWAVES, RADAR AND REMOTE SENSING SYMPOSIUM.

[3]  Tae Ho Kim,et al.  A doherty amplifier with a bias adaptation technique based on SDR transmitter architecture , 2005 .

[4]  Jangheon Kim,et al.  Analysis of a Fully Matched Saturated Doherty Amplifier With Excellent Efficiency , 2008, IEEE Transactions on Microwave Theory and Techniques.

[5]  Kimberley W. Eccleston,et al.  The effect of FET soft turn-on on a Doherty amplifier , 2008 .

[6]  S. C. Cripps,et al.  RF Power Amplifiers for Wireless Communications , 1999 .

[7]  K. Bathich,et al.  Harmonically tuned GaN-HEMT Doherty power amplifier for 6 GHz applications , 2011, 2011 6th European Microwave Integrated Circuit Conference.

[8]  F. Raab,et al.  Power amplifiers and transmitters for RF and microwave , 2002 .

[9]  Zongxi Tang,et al.  Linearity Improved Doherty Power Amplifier Using Coupled-Lines and a Capacitive Load , 2011, IEEE Microwave and Wireless Components Letters.

[10]  V. Camarchia,et al.  A 22W 65% efficiency GaN Doherty Power Amplifier at 3.5 GHz for WiMAX applications , 2011, 2011 Workshop on Integrated Nonlinear Microwave and Millimetre-Wave Circuits.

[11]  S. Carichner,et al.  An Improved Doherty Amplifier Using Cascaded Digital Predistortion and Digital Gate Voltage Enhancement , 2009, IEEE Transactions on Microwave Theory and Techniques.

[13]  Thomas Lejon,et al.  High efficiency power amplifiers , .

[14]  John Wood,et al.  A linear 250 watt Doherty power amplifier based on two-stage power ICs for 1.8 GHz single and multi-carrier GSM applications , 2009, 2009 IEEE MTT-S International Microwave Symposium Digest.

[15]  A. Grebennikov.  High‐Efficiency Power Amplifiers , 2011 .

[16]  Jangheon Kim,et al.  The Doherty power amplifier , 2006, IEEE Microwave Magazine.

[17]  P. Colantonio,et al.  A 6W uneven doherty power amplifier in GaN technology , 2007, 2007 European Microwave Conference.

[18]  Kimberley W. Eccleston,et al.  A theoretical basis for Doherty amplifier bias control based on drain current characteristics , 2009 .

[19]  Jangheon Kim,et al.  Advanced design methods of Doherty amplifier for wide bandwidth, high efficiency base station power amplifiers , 2005, 2005 European Microwave Conference.

[20]  L.C.N. de Vreede,et al.  A High-Efficiency 100-W GaN Three-Way Doherty Amplifier for Base-Station Applications , 2008, IEEE Transactions on Microwave Theory and Techniques.

[21]  Bumman Kim,et al.  Doherty amplifier with envelope tracking for high efficiency , 2010, 2010 IEEE MTT-S International Microwave Symposium.

[22]  F. M. Ghannouchi,et al.  Digital Doherty Amplifier With Enhanced Efficiency and Extended Range , 2011, IEEE Transactions on Microwave Theory and Techniques.

[23]  J. Staudinger,et al.  High-Efficiency Power Amplifiers , 2012, IEEE Microwave Magazine.

[24]  Rolf H. Jansen,et al.  Broadband Doherty Power Amplifier via Real Frequency Technique , 2012, IEEE Transactions on Microwave Theory and Techniques.

[25]  Bumman Kim,et al.  Advanced Doherty Architecture , 2010, IEEE Microwave Magazine.

[26]  Jangheon Kim,et al.  Advanced Design of Linear Doherty Amplifier for High Efficiency using Saturation Amplifier , 2007, 2007 IEEE/MTT-S International Microwave Symposium.

[28]  Bumjae Shin,et al.  A microwave Doherty amplifier employing envelope tracking technique for high efficiency and linearity , 2003 .

[29]  Georg Boeck,et al.  A wideband GaN Doherty amplifier with 35 % fractional bandwidth , 2010, The 40th European Microwave Conference.

[30]  Bumman Kim,et al.  Optimum operation of asymmetrical-cells-based linear Doherty power Amplifiers-uneven power drive and power matching , 2005, IEEE Transactions on Microwave Theory and Techniques.

[31]  Yi-Jan Emery Chen,et al.  Impact of bias schemes on Doherty power amplifiers , 2005, 2005 IEEE International Symposium on Circuits and Systems.

[32]  Jin Joo Choi,et al.  High efficiency Class-E tuned Doherty amplifier using GaN HEMT , 2009, 2009 IEEE MTT-S International Microwave Symposium Digest.