Behavioural modelling of thermally induced distortion in RF/microwave nonlinear subsystems

Low-frequency thermal transients may give a relevant contribution to the generation of intermodulation distortion in nonlinear RF subsystems such as power amplifiers, where significant self-heating takes place. The paper discusses a simple and accurate behavioural model whereby such effects may be simulated with excellent accuracy and high computational speed. The model relies upon a parametric description of the relationships between the linear and nonlinear subsystem responses, and makes use of a relaxation method to efficiently evaluate the temperature waveforms.