A new nonlinear HEMT model for AlGaN/GaN switch applications

We present here a new set of equations for modeling the I-V characteristics of FETs, particularly optimized for AlGaN/GaN HEMTs. These equations describe the whole characteristics from negative to positive breakdown loci, and reproduce the current saturation at high level. Using this model allow reducing the modeling procedure duration when a same transistor topology is used for several applications in a T/R module. It can even be used for switches design, witch is the most demanding application in terms of I-V swing. Moreover, a particular care was taken to model accurately the first third orders of the current derivatives, which is important for multitone applications. There are 18 parameters for the main current source (and 6 for both diodes Igs and Igd). This can be compared to the Tajima's equations based Model [1] (13 parameters) or to the Angelov Model (14 parameters) [2], which only fit the I-V characteristics for positive values of Vds. We will detail here the model formulation, and show some measurements/modeling comparisons on both I-V and [S]-parameters obtained for a 8×75 µm GaN HEMT.