Sub-terahertz resistive mixing in an AlGaN/GaN FET

An AlGaN/GaN based field effect transistor (FET) has been designed, fabricated, and used as a resistive mixer for heterodyne detection in the 140-220 GHz frequency range. A double VNA heterodyne measurement setup has been used in an on-wafer configuration to accurately quantify the incident radiation absorbed by the device. The appropriate selection of optimum biasing conditions for minimum conversion losses is investigated. 47.3 dB conversion losses are obtained at 150 GHz and the device linearity is confirmed.