Electro-thermal simulation in the time domain of GaN HEMT for RF switch-mode amplifier

Accurate transient temperature prediction in GaN devices is an increasingly important process in the design of dependable radio frequency systems. In this paper, a methodology for dynamic electro-thermal simulation of GaN microwave and power devices is presented, which bases on the extraction of compact thermal models by three-dimensional finite element simulation. The obtained compact thermal model is coupled to an electric compact model, where the temperature dependence of the lumped elements is described analytically. The proposed methodology is applied to the case of GaN HEMTs used in a voltage mode D-class radio frequency amplifier operated in the frequency range from 300 MHz up to 3 GHz.