DC/RF characterization and modeling of illuminated microwave GaAs MESFETs

A systematic approach to the characterization and modeling of DC and RF behavior of microwave GaAs MESFETs under quasi-static optical illumination is presented. A set of measurements aiming at separating direct and indirect effects is discussed, and a general, nonlinear, light-intensity-dependent circuit model capable of accounting for both of them is proposed. The experimental results pertaining to the characterization of a commercial device are then presented. On this basis, the general model is particularized into a simplified first-approximation model, whose accuracy is checked by comparing a set of additional measurements with the relevant computer-simulated results