A scalable GaN HEMT large-signal model for high-efficiency RF power amplifier design

This paper presents a large-signal empirical model for GaN HEMT devices using an improved Angelov drain current formulation with self-heating effect and a modified non-linear capacitance model. The established model for small gate-width GaN HEMTs is validated by on-wafer load-pull measurements up to 14 GHz. Moreover, a scalable large-signal model is presented by adding scalable parameters to drain-source current and non-linear capacitance equations. The scalable model of a 1.25 mm GaN HEMT has been employed to design a class-AB power amplifier for validation purposes. The results show that good agreement has been achieved between the simulated and measured results with 37.2 dBm saturation output power (Psat) and 58% maximum power-added-efficiency at 3 GHz.