Two-Way Doherty Power Amplifier Efficiency Enhancement by Incorporating Transistors’ Nonlinear Phase Distortion

This letter starts with describing the efficiency of two-way Doherty power amplifier (DPA) in the presence of the nonlinear phase distortion of the constituent transistors. Combined with the proper choice of the complex-valued load impedance's reactance, this analysis directed the design of DPA with enhanced efficiency over extended output back-off power region and bandwidth. Results of measurement conducted using a proof-of-concept demonstrator designed to operate in the frequency band ranging from 1.35 to 1.7 GHz revealed average efficiency of 59%-62% under 20-MHz long-term evolution modulated signal.