An improved but reliable model for MESFET parasitic capacitance extraction

The conventional parasitic capacitance extraction always produces bias-dependent C/sub pd/, even though from the underlying physic, the parasitic capacitance is known to be bias-independent. In this paper, an improved model is thus proposed to evaluate the parasitic capacitances of GaAs MESFET transistor from the cold-FET S-parameters measurement. The resulting C/sub pd/ is found to be independent of V/sub gs/ when V/sub gs/ < V/sub p/. In our approach, model parameters can be uniquely determined by using only two sets of cold-FET S-parameters under different Vgs biasing condition.