Analysis and optimum design of impedance matching for Ka-Band cryogenic low noise amplifiers

High electron mobility transistors (HEMTs) and cryogenic cooling are widely employed in high gain and low noise millimeter-wave amplifiers. By using the temperature dependant model of HEMT, this paper further investigated the optimum impedance matching for low noise amplifiers (LNAs) to exhibit a significant improvement in noise and gain performance under cryogenic temperatures. One MMIC LNA covering 26-40 GHz frequency band has been developed on GaAs substrate with 0.15 ¿m pHEMT devices, and it was measured on-wafer and in-module at the operating temperatures of 300 K and 77 K.