Thermal response for intermodulation distortion components of GaN HEMT for low and high frequency applications

Abstract

Thermal effect on intermodulation distortion (IMD) behavior of GaN based high-electron mobility transistor (HEMT) have been researched over input power and frequency using a two-tone technique. A significant modification was observed in terms of magnitude on the linear component and the magnitude as well as the position and appearance of the nulls/notches of the nonlinear components was changed conspicuously. The parasitic resistances and as well as the output current were affected when applied input power increases. As a result, an increase in the output IMDs found and the device threshold voltage VT moves towards more negative of Vgs trace which in turn shifts the notch points of the nonlinear IMDs towards lower values of applied bias Vgs. The values of the output IMDs degrades with the increment of temperature and frequency. The output IMD products also reduced following the transconductances response to temperature. On the other hand, the notch/null's position of the nonlinear IMDs also moves following the thermal response of threshold voltage. This authentic and exhaustive study is crucial to figure out the minimum distortion, maximum gain bias option for active devices.