70-116-GHz LNAs in 35-nm and 50-nm Gate-Length Metamorphic HEMT Technologies for Cryogenic and Room-Temperature Operation

In this paper, the room-temperature and cryogenic performance of two low-noise amplifier (LNA) modules in the frequency range from 70 to 116 GHz is presented and analyzed. The investigation is based on LNA millimeter-wave integrated circuits using 35-nm and 50-nm gate-length metamorphic high-electron-mobility transistor technologies. At room temperature, the WM-2540 waveguide modules demonstrate an average noise temperature of 214 and 247 K over the 70-116-GHz frequency range. The lowest achieved noise temperatures are 171 and 196 K. When cooling the LNA modules to an ambient temperature of 6 K, the average noise temperatures improve to 30.1 and 31 K. The lowest achieved noise temperatures are 20.7 and 19.2 K. To the best of the authors' knowledge, the demonstrated LNAs yield the lowest published average noise temperatures at room temperature over the 70-116-GHz frequency range. Furthermore, the achieved cryogenic noise performance is among the best results published so far.