Intrinsic GaAs MESFET equivalent circuit generated from a new analytical model

An analytical, physically-based, GaAs MESFET model is used to generate an AC small-signal equivalent circuit useful for amplifier design and device diagnostics. In the saturated operation the conducting channel is represented by a two-resistive part model, namely, the fully-depleted and graded-depleted parts. The latter part can be accurately represented by the channel-length modulation parameter. For a 1-μm gate-length FET, the AC equivalent circuit parameters are evaluated as a function of drain-source and gate-source bias voltages. AC small-signal analysis is carried out at different bias conditions. A comparison with a two dimensional simulation-based model and another analytical model is introduced. A considerable minimization of error for this analytical model frequency response is noticed