Direct extraction of equivalent circuit parameters for GaAs pHEMT

A new direct parameter extraction method to determine the small signal equivalent circuit model for pseudomorphic high electron-mobility transistors is presented in this paper. This method is a combination of the test structure method and analytical method without reference to numerical optimization. Good agreement is obtained between simulated and measured results for 2×20 μm and 2×40 mu;m gate width (number of gate fingers×unit gate width) 0.15 μm pHEMTs in the frequency range of 50 MHz∼40 GHz over a wide range of bias points. Model verification is also carried out by comparison of measured and simulated S-parameters in the frequency range of 75∼110 GHz, demonstrating that this approach is valid for 50 MHz∼110 GHz frequency range.