Accurate Nonlinear Characterization and Modeling of the GaAs FET

Contrary to previous conventional characterizations and modelisations, which employ the dc measurements of the drain current Ids(Vgs, Vds), we propose a new mode of nonlinear characterization of the GaAs FET. Ths is based on the knowledge of the voltage dependence of the transconductance gm and the output conductance gd values measured in the microwave frequency range. This new mode of characterization is thus more accurate and precise than conventional ones, because the latter are tainted with errors due to thermal and trap effects, which are parasitic with respect to the microwave behaviour of the FET. Thus, a numerical integration of the measured microwave parameters gives us the accurate quasi-static characteristics. On the other hand, we present an accurate model which takes into account the device nonlinearities. Finally our method has been used to model a medium power amplifier, in X-band operating.