Estimation of the accuracy of a simplified equivalent circuit for Ku-band GaN HEMTs

Abstract We investigate the accuracy of the intrinsic FET's equivalent circuit with only one nonlinear element – the channel current generator given by the Curtice-Ettenberg model. The parameters of this simplified equivalent circuit are assigned using the 2D quasi-hydrodynamic simulation taking into account the electron velocity overshoot. We calculated the power-added efficiency, transducer power gain, and other amplifier parameters as functions of the maximum available power of an 18-GHz input generator by three methods: using the full 2D model for the intrinsic FET and the large-signal equivalent circuit – complete and simplified. Comparison of the functions obtained indicates the suitability of the simplified equivalent circuit for analysis of GaN HEMT power amplifiers of the Ku band. Since this equivalent circuit is implemented in various commercial software packages for analysis and design of RF and microwave devices, our 2D simulation results can be used in these packages.