Modified Output Combining 3-Stage Doherty Power Amplifier Design for LTE Micro eNodeB

This paper presents a highly efficient modified output combining 3-stage Doherty Power Amplifier (DPA) design using low power LDMOS transistor for Band 40, TD-LTE Micro eNodeB. In this design, modified output combining technique has been used in the output section which meets the output power requirements of Micro eNodeB which cannot be achieved by conventional 3-stage DPA. The modified DPA design achieves 65.3% power added efficiency (PAE) at 39 dBm average output power with 20 MHz LTE signal using 15 watt LDMOS Transistor. 3-stage modified output combining technique increases the linear output power by 1.1 dB and increases the Gain flatness versus power level. The use of Digital Pre-Distortion (DPD) along with modified 3-stage DPA design achieves the linearity requirements as per the 3GPP specifications. The modified DPA combining technique has provided potential economical solution by using low power LDMOS transistor with an advantage of high efficiency.

[1]  F. Raab.  Intermodulation distortion in Kahn-technique transmitters , 1996 .

[2]  George B. Norris,et al.  800 MHz power amplifier using envelope following technique , 1999, RAWCON 99. 1999 IEEE Radio and Wireless Conference (Cat. No.99EX292).

[3]  George B. Norris,et al.  High efficiency CDMA RF power amplifier using dynamic envelope tracking technique , 2000, 2000 IEEE MTT-S International Microwave Symposium Digest (Cat. No.00CH37017).

[4]  P. Asbeck,et al.  An extended Doherty amplifier with high efficiency over a wide power range , 2001, 2001 IEEE MTT-S International Microwave Sympsoium Digest (Cat. No.01CH37157).

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

[6]  Jangheon Kim,et al.  Optimum operation of asymmetrical-cells-based linear Doherty power Amplifiers-uneven power drive and power matching , 2005 .

[7]  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.

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

[9]  P. Bhatnagar,et al.  Efficient Doherty Feed-forward Linear Power Amplifier for CDMA 2000 Base-Station Applications , 2008, 2008 International Conference on Signal Processing, Communications and Networking.

[10]  T. Nojima,et al.  A 2-GHz band experiment on efficiency enhancement of a GaN power amplifier using 2nd harmonic injection , 2008, 2008 Asia-Pacific Microwave Conference.

[11]  Franco Giannini,et al.  The AB-C Doherty power amplifier. Part II: Validation , 2009 .

[12]  Albrecht J. Fehske,et al.  Energy Efficiency Improvements through Micro Sites in Cellular Mobile Radio Networks , 2009, 2009 IEEE Globecom Workshops.

[13]  A. Z. Markos,et al.  A 50 W unsymmetrical GaN Doherty amplifier for LTE applications , 2010, The 40th European Microwave Conference.

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

[15]  Jinsung Choi,et al.  High efficiency and wideband envelope tracking power amplifier with sweet spot tracking , 2010, 2010 IEEE Radio Frequency Integrated Circuits Symposium.

[16]  A. Z. Markos,et al.  Design of a 120 W balanced GaN Doherty power amplifier , 2011, 2011 German Microwave Conference.

[17]  吉川 俊英,et al.  GaN device for highly efficient power amplifiers , 2011 .

[18]  Zhibin Zeng,et al.  A Crest Factor Reduction Method in Digital Predistortion for Improvement of Power Efficiency , 2012, 2012 International Conference on Computer Science and Electronics Engineering.

[19]  Khaled Bathich,et al.  Analysis and Design of Efficiency-Enhancement Microwave Power Amplifiers Using the Doherty Technique , 2013 .

[20]  E. G. Lima,et al.  FPGA Implementation of a Fix-Point Digital Baseband Pre-Distorter for the Linearization of Wireless Transmitters , 2013 .

[21]  Rosdiadee Nordin,et al.  Survey of Green Radio Communications Networks: Techniques and Recent Advances , 2013, J. Comput. Networks Commun..

[22]  Franco Giannini,et al.  Asymmetrical Doherty power architecture with an integrated driver stage in the auxiliary branch , 2014 .