A drain lag model for GaN HEMT based on Chalmers model and pulsed S-parameter measurements

This paper addresses a novel approach to account for trapping effects in the large-signal description of GaN HEMTs. Instead of relying on an internal effective gate voltage, which is not very intuitive, it is investigated how the Chalmers (Angelov) model parameters are altered by trapping. It is verified that such an approach enables reliable load-pull prediction over a wide range of drain bias voltages. In addition, appropriately scaled parameters are shown to allow for a good estimation of large-signal performance even if the model itseff misses a dedicated trapping description.