A new design method for distributed Doherty power amplifier

This paper introduces the basic theory of a new type of Distributed Doherty Power Amplifier (DDPA) architecture, which uses a step-by-step current injection method for load modulation to improve the modulation network order of the main amplifier and reduce the impedance conversion ratio, thereby increasing the operating bandwidth. The load modulation trajectory and drain efficiency under single-frequency point and wideband range with 6 dB and 8 dB back-off were analyzed, and the effect of peaking branches output phase on the load modulation trajectory and drain efficiency curve were also analyzed. Finally, a DDPA working at 1.5-2.7 GHz (57.1 % relative bandwidth) was designed using Wolfspeed's CGH40025 transistor. The physical simulation results show that its saturated output power reaches 47.7-48.8 dBm, the saturated gain is 5.17-8.9 dB, and the saturated drain efficiency is 46.53-61 %. The drain efficiency under 8 dB back-off is 43.5-53.7 %, and the drain efficiency under 6 dB back-off is 58.37 %-67.85 %.