Accurate multibias equivalent-circuit extraction for GaN HEMTs

This paper focuses on the determination and analysis of an accurate small-signal equivalent circuit for gallium-nitride high electron-mobility transistors under different bias conditions. Our experimental results show that a channel capacitance has to be added to the conventional forward "cold" model for modeling the device-under-test. The validity of the proposed extraction procedure has been verified by the very good agreement between simulated and measured scattering parameters up to 50 GHz