Distributed small signal model for multi-fingered GaAs PHEMT/MESFET devices

A fully distributed equivalent circuit PHEMT and MESFET model is presented in closed form expressions for single finger end-fed FET geometry. The model includes self and mutual inductances and a new frequency dependent gate resistance. The model was used successfully to model multi-fingered devices which were subjected to equi-phase gate and drain excitations. Comparisons between measured data and model results are shown to be in excellent agreement for all S-parameters to 50 GHz regardless of unit gate width. Scaling issues are also investigated for the new distributed model.