An Efficient Broadband Symmetrical Doherty Power Amplifier With Extended Back-Off Range
Jian Rong Zhang, Shao Yong Zheng, Nan Yang
Abstract
In this brief, a symmetrical Doherty power amplifier (DPA) which exhibits enhanced efficiency, bandwidth and output power back-off range by phase compensation, is proposed. This proposed architecture compensates the phase deviation between main and auxiliary amplifiers mainly caused by the load modulation circuit and parasitic parameters of transistors. With phase compensation, both saturation efficiency and bandwidth are significantly improved while maintaining an extended output back-off range. For verification, a 2.05–2.8-GHz symmetrical DPA is designed, fabricated and measured. Under continuous wave excitation, measurement results show that the implemented DPA exhibits drain efficiency of 40%–49% at 9 dB output back-off level and 66%–76% at saturation with a maximum output power of 43.9–44.9-dBm over the entire band.