A Universal Large-Signal Equivalent Circuit Model for the GaAs MESFET

A large-signal equivalent circuit model is developed for a GaAs MESFET which is intended to be "universal", i.e. valid for DC, small-signal and nonlinear operation over a very wide range of bias conditions. Novel features of the proposed approach include accurate sub-threshold modelling, and allowance for dispersion in both transconductance and drain-source conductance. A sequential procedure is outlined, based on a range of experimental measurements, for characterising a given device in terms of the model parameters.