Experimental investigation of 3-W class-AB cryogenically-cooled amplifier employing GaN HEMT for front end receivers of mobile base stations Original Research Article

This paper presents experimental results of a 2-GHz band gallium nitride high electron mobility transistor (GaN HEMT) amplifier cryogenically-cooled to 60 K as a part of the cryogenic receiver front end (CRFE) for mobile base station receivers. At a temperature of 60 K, the GaN HEMT amplifier attains the maximum power added efficiency of 62%, the saturation output power of 35 dBm, the gain of 26 dB, and the noise figure of 2.6 dB when operating at class-AB biasing. The results reported herein are the first on the performance of a cryogenically-cooled GaN HEMT amplifier aiming at use in a 2-GHz band CRFE.