A Large-Signal Model of GaN HEMTs for Linear High Power Amplifier Design

A nonlinear large-signal table-based model of AlGaN/GaN HEMTs that able to predict output nonlinearities including intermodulation distortions (IMD) is described. The equivalent circuit model elements of the dispersive model are derived from S-parameter and pulsed DC I(V) measurements. With proper data processing and implementation, the speed and accuracy of simulations under multi-tone excitations are improved. Particularly, making the data available for larger grid voltage has minimized unrealistic extrapolation by circuit simulator. Similarly, data interpolation for denser voltage grid before implementation in the circuit simulator reduced interpolation problems. Using a continuously differentiable analytical model for the main nonlinear parameter (the drain current) can further enhance the IMD prediction capability at lower power levels