In this paper, a new 20-element small-signal equivalent circuit for GaN HEMTs is proposed and correspondingly, a direct extraction method is developed. Compared with the 16-element conventional GaAs-based HEMT small-signal model (SSM), two parasitic distributed inter-electrode extrinsic capacitances and two additional feedback intrinsic resistances are considered. The new modeling approach for GaN HEMTs is verified by comparing the simulated small-signal S-parameter with the measured data over wide frequency and bias ranges. (C) 2007 Elsevier Ltd. All rights reserved.