Total charge capacitor model for short-channel MESFETs

Total charge models for short-channel metal-semiconductor field-effect transistors (MESFETs) currently available in large-signal simulator packages such as SPICE give a poor description of the bias dependence of the gate capacitance. The authors describe a novel empirical model whose structure is deduced from the reconstructed total charge function derived from measured S-parameters. The new model gives a good overall fit to the observed gate capacitance behavior of a commercial monolithic microwave/millimeter-wave integrated circuit (MMIC) MESFET over a wide range of bias conditions and enables large-signal MESFET models to have a superior fit to measured S-parameters, giving greater confidence in design