Fast and efficient procedures for determining the microwave noise parameters of HEMT's at decreasing temperatures

Abstract
Noise parameters are an electrical representation of the noise performance of transistors which is widely used in reliability studies as well as in the design of low-noise microwave amplifiers. Such parameters are usually determined by employing a complex indirect (standard) procedure based on multiple noise figure measurements and appropriate data processing techniques. We report here two alternative and rapid methods used to perform the complete noise characterization of HEMT's at decreasing temperatures over the 6 to 18 GHz frequency range. The results show a very satisfactory agreement among the different procedures thus assessing the inherent consistency of the global approach to the problem of the noise characterization of active devices.