The validity of the quasi-static GaAs FET model

摘要

Large-signal equivalent circuit FET models rely on the validity ofnthe quasi-static assumption. That is to say that the element values arenassumed to change instantaneously with their controlling voltages andnthat these voltage relationships do not vary with time. This assumptionnis used to construct microwave frequency models from elements whosennonlinearities have been established with respect to DC bias voltages.nHowever, low frequency dispersion effects are known to degrade GaAsnMESFET performance, and this compromises the accuracy achievable by thisnapproach. The authors report on an investigation into the validity ofnGaAs MESFET models which are based on DC I-V characteristics andnconsider the effectiveness of simple linear correction factors. The usenof a fast pulse technique is compared, which provides a directnmeasurement of the large-signal dynamic performance of the FET currentngenerators