A High-Temperature Model for GaN-HEMT Transistors and its Application to Resistive Mixer Design

Abstract

This article presents a high temperature model for gallium nitride (GaN) high electron mobility transistor (HEMT) on silicon carbide (SiC). The proposed model for the channel resistance $\text {R}_{\text {ds}}$ is based on an empirical nonlinear model. The model is applied to design a resistive mixer of a high temperature transceiver for downhole communications through a systematic approach and estimate the performance of the mixer. The proposed model matches well with measurement results of the mixer and accurately estimates its performance at temperatures up to 250 °C. The model is also applied to obtain the optimal gate bias voltage of the mixer for a given temperature. The optimal bias voltage scheme reduces the conversion loss of the mixer by a factor of 8.4 dB at 250 °C under the local oscillator power of −10 dBm.