Experimental study on load dependent X-parameter models for PA design

The X-parameter model is designed for modeling weakly nonlinear devices in an approximately impedance-matched environment. Load dependent X-parameter models were proposed to overcome this, practically very relevant, limitation and model a nonlinear device in a highly mismatched environment. However, the applicability of load dependent X-parameter models for DUTs operating in deep saturation like in power amplifier design is questionable. This work evaluates the possibilities of using a load dependent X-parameter model in power amplifier design by comparing the results of a model build from measurements of a GaN-HEMT to in-situ measurements of the same device.