Dual-Input Mixed-Mode Doherty-Outphasing Power Amplifier

This work proposes a new output combiner for the mixed-mode Doherty-Outphasing power amplifier (DOPA) architecture, which is able to guarantee a real load-modulation during the Doherty operation. A comprehensive explanation of the proposed DOPA combiner and its optimum driving signals is presented. For validation, an ideal DOPA was implemented in a simulator using ideal piece-wise current sources for representing the nonlinear transistors and an exhaustive search for the optimum driving signals was conducted, demonstrating the real load-modulation in the Doherty region. To demonstrate the feasibility of the proposed combiner, a 2 GHz 60 W Mixed-Mode Doherty-Outphasing PA based on GaN HEMTs was designed, presenting an efficiency higher than 50% over 11 dB of output power back-off.