Nonlinear modeling of GaAs pHEMTs for millimeter-wave mixer design

•Extraction of nonlinear equivalent circuit of GaAs pHEMTs for mixer design.•Model validation based on high-frequency nonlinear measurements.•Design of a packaged Q-band up-converter based on cold-FET mixer. The present paper was focused on the extraction of a GaAs pHEMT nonlinear model meant for mixer design. The model is based on an equivalent circuit that is analytically extracted from DC and multi-bias S-parameter measurements. The look-up table approach is used to implement the model in a nonlinear RF circuit simulator. The model accuracy is extensively verified by comparing device measurements and simulations under a wide range of operating conditions. Furthermore, to corroborate the validity of the model, the design of a Q-band up-converter is considered.