An analytical model for the S-parameters of optically controlled GaAs MESFET's

A new analytical model for the microwave characteristics of optically controlled GaAs MESFET (OPFET) in terms of S-parameters is presented in this paper. The novelty of this model lies in the calculation of photo induced gate voltage. Using that photo voltage, we have analyzed the photo effects on intrinsic parameters of MESFET. To make this characterization effective and accurate, we have included the Gunn domain capacitance, domain resistance, transit time effect, low frequency anomalies and parasitic elements in the equivalent circuit of MESFET. We have compared our results in both dark and illuminated conditions with the reported one to show the validity of the model.