Using modified GaAs FET model function for the accurate representation of PHEMTs and varactors

In the recent PSpice programs, several GaAs FET models of various classes have been implemented. However, some of them are sophisticated and therefore very difficult to measure and identify afterwards, especially the realistic model of Parker and Skellern. In the paper, simple enhancement of one of the standard models is proposed. The resulting modification is usable for the accurate modelling of both GaAs FETs and PHEMTs. Moreover, its updated capacitance function can serve as a precise representation of microwave varactors, which is more important.