An Experimental Study for the Design of Dual Input Load Modulated Wideband GaN Amplifier

In this paper, we present an experimental study focused on the characterization of a dual input Doherty Power Amplifier (DPA). A calibrated set-up is used for an accurate characterization of a DPA demonstrator and the study of several input driving conditions. A demonstrator PA which uses two packaged 10-W GaN HEMT from Wolfspeed was fabricated. Measurements obtained for several driving conditions (power levels and relative phase differences) show Drain Efficiency (DE) performances of DE≈55% at 6-dB Output Back Off (OBO) and DE≈60% at 20-W saturated power over a 2.1-2.6 GHz bandwidth. The main focus of the paper concerns the trade-off between efficiency and power gain shape versus output power that can be obtained with dual input architectures and input signal driving conditions.