Symmetrical Doherty Power Amplifier With Extended Efficiency Range
A symmetrical Doherty power amplifier (PA) with an extended efficiency range is proposed. This paper proves the existence of a class of symmetrical Doherty PAs having efficiency peaks for back off levels larger than 6 dB. A design technique is developed that maintains the full voltage and current swings of both the main and auxiliary transistors. The concept is experimentally verified in a 1.95 GHz 25 W circuit demonstrator fabricated using identical GaN HEMT devices. An average power added efficiency of 50% and adjacent power leakage ratio of 49 dBc is obtained with 9 dB peak to average power ratio 20 MHz long term evolution test signals.
IEEE Transactions on Microwave Theory and Techniques