An approach for extracting small-signal equivalent circuit of double heterojunction δ-doped PHEMTs for millimeter wave applications

Pseudomorphic high electron mobility transistors (PHEMTs) are very important in millimetervave application. A simple and accurate method for extracting small-signal equivalent circuit for Double Heterojunction δ-doped PHEMT valid up to 40GHz is presented. First, the parasitic parameters of the equivalent circuit are determined using pinch off PHEMT except for PAD capacitances. The initial intrinsic elements are then determined by conventional analytical method. Advanced Design System is then used to optimize the whole model parameters with very small dispersion of initial values. Good agreement is obtained between simulation results and measured results for a 0.25um DH PHEMT.