Nonlinearities in FET/HEMT microwave devices for circuit synthesis applications

Numerous microwave circuits utilize the properties of active elements that operate under large signal conditions. In particular, active frequency conversion circuits employ the nonlinearities resident in microwave transistors such as MESFETs and HEMTs. This paper analyzes the various nonlinear mechanisms possessed by MESFETs and HEMTs with the goal of utilizing these to provide for optimal designs. The major emphasis is placed on the quantitative contribution of each nonlinearity (e.g., I/sub ds/, g/sub d/, C/sub gs/, etc.) to overall harmonic generation. Numerical results are provided utilizing nonlinear simulation software.