Influence of the temperature on the equivalent noise resistance of HEMT's at microwave frequencies

This paper is focused on the performance of the noise resistance Rn of HEMT's at microwave frequencies as a function of temperature. A sensitivity analysis has been performed on several noisy circuit models of low-noise devices that we had previously characterized in terms of scattering and noise parameters. Such a study has been aimed at pointing out the role played by either the electrical elements and the noise temperatures of the resistors of the equivalent circuit on the typically observed U-shaped behavior of Rn.