GaN HEMT modelling through 50-Ω NF measurements

In this paper a small-signal and noise transistor model with the associated extraction procedure is proposed. The model is based on an equivalent circuit, extracted from electromagnetic simulations and noise measurements using an automatic analytical procedure. This identification procedure ensures high robustness to layout modifications, making the model suitable for low-noise amplifier design. An equivalent temperature approach is exploited for noise modelling: every passive element of the equivalent circuit is considered at room temperature, except for the intrinsic drain conductance. Its equivalent temperature is extracted by simply fitting the noise figure for a 50 Ω source termination. The proposed technique allows a very good accuracy of the noise parameter predictions for degenerated devices, avoiding expensive and time consuming noise parameter characterization.