High efficiency 8.8–9.6 GHz class J power amplifier

This paper presents the first implementation of hybrid 8.8-9.6 GHz X-band class J power amplifier (PA) designed with a GaN HEMT power transistor. High efficiency power amplifiers suffer from nonlinear performance and relatively low bandwidth. The proposed high efficiency class J power amplifier provides larger bandwidth and more convenient linearity performance. The class J PAs should have appropriate matching networks at second harmonic of fundamental frequency which cannot easily realize for high frequency hybrid PAs. In the proposed Class J PA, second harmonic matching network was achieved by using low parasitic GaN HEMT power transistor and precise modeling of transmission lines and passive elements up to 20 GHz. The optimum dimensions of matching networks are determined by employing optimizing algorithm. This PA achieves 14 dB power gain over the frequency range of 8.8-9.6GHz. Drain efficiency and power added efficiency are about 67% and 58% at 9.3 GHZ, respectively that is about 5% higher than class AB X-band power amplifier that is implemented in similar condition.

[1]  Georg Boeck,et al.  Investigation of class-B/J continuous modes in broadband GaN power amplifiers , 2012, 2012 IEEE/MTT-S International Microwave Symposium Digest.

[2]  Kyung-Whan Yeom,et al.  Design of X-band 40 W Pulse-Driven GaN HEMT power amplifier , 2012, 2012 Asia Pacific Microwave Conference Proceedings.

[3]  M. L. Edwards,et al.  A new criterion for linear 2-port stability using a single geometrically derived parameter , 1992 .

[4]  M.C.E. Yagoub,et al.  A GaN HEMT Class-F amplifier for UMTS/WCDMA applications , 2008, 2008 IEEE International RF and Microwave Conference.

[5]  D. M. Snider,et al.  A theoretical analysis and experimental confirmation of the optimally loaded and overdriven RF power amplifier , 1967 .

[6]  Bumjin Kim,et al.  Broadband high efficiency GaN discrete and MMIC power amplifiers over 30 – 2700 MHz range , 2014, 2014 IEEE MTT-S International Microwave Symposium (IMS2014).

[7]  J. Papapolymerou,et al.  An X-band GaN HEMT hybrid power amplifier with low-loss Wilkinson division on AlN substrate , 2013, 2013 IEEE International Conference on Microwaves, Communications, Antennas and Electronic Systems (COMCAS 2013).

[8]  Bumman Kim,et al.  Investigation of a Class-J Power Amplifier With a Nonlinear $C_{\rm out}$ for Optimized Operation , 2010, IEEE Transactions on Microwave Theory and Techniques.

[9]  Hartmut Hillmer,et al.  An enhanced quasi-monolithic integration technology for microwave and millimeter wave applications , 2003 .

[10]  Christian Fager,et al.  Highly efficient GaN-HEMT power amplifiers at 3.5 GHz and 5.5 GHz , 2011, WAMICON 2011 Conference Proceedings.

[11]  Matthew Poulton,et al.  Compact highly integrated X-band power amplifier using commercially available discrete GaN FETs , 2011, Asia-Pacific Microwave Conference 2011.

[12]  Leonid Belostotski,et al.  Integrated Design of a Class-J Power Amplifier , 2013, IEEE Transactions on Microwave Theory and Techniques.

[13]  J. Lees,et al.  On the Continuity of High Efficiency Modes in Linear RF Power Amplifiers , 2009, IEEE Microwave and Wireless Components Letters.