GaAs DGMESFET modeling using SGMESFET models

This paper presents a complete and enhanced model for dual-gate MESFETs (DGMESFETs) using a cascode connection of dual single-gate MESFETs (SGMESFET) embedded by a group of external parasitic elements. An enhanced bias and frequency-dependent SGMESFET model is employed for internal SGFET´s, which accounts for charge-conservation and thermal effects. The initial values of the model parameters are obtained by measurement of DC and S-parameters. The parameters are then optimized using SAS, MATLAB and HSPICE. The model is implemented in HSPICE and its accuracy in predicting the characteristics of a NE25139 transistor is tested by DC and AC analysis.