Linearity Issues in Dual Input Doherty-Outphasing Hybrid Power Amplifier Topology

In this study, the Doherty-Outphasing technique, designed to achieve higher back-off power values with flatter efficiency characteristics, is investigated in terms of linearity and linearizability. The hybrid concept is introduced to determine the trajectories of load modulation, which plays a dominant role in the linearity of power amplifiers. Amplitude and phase distortions are fundamental criteria for evaluating the linearity performance in the average efficiency techniques using complex modulation signals. Therefore, the analytical expressions of these nonlinearities of the power amplifiers have to be explained rigorously. As a goal of this paper, the linearity and linearizability mechanisms based on GaN HEMT are constructed using the analytical approach.