A large-signal model for GaAs MESFET's and HEMT's valid at multiple DC bias-points

In this paper we present a general-purpose GaAs FET nonlinear circuit model, for universal use (DC, small-signal and large-signal) which is valid at multiple DC operating points. Novel features of the model include: (i) a direct and reliable multi-bias point parameter extraction methodology (no optimisation required), based solely on CW S-parameter measurements, with an improved approach to the extraction of the parasitic resistances; (ii) more accurate models for the main non-linearities, with special attention paid to the gate capacitances, the intrinsic resistance and high-frequency dispersion in the drain circuit. The validity of the model is demonstrated through extensive power-sweep tests, carried out at different DC bias-points and different frequencies.