Ultra-Low-Noise Cryogenic PHEMT Amplifiers

Abstract

A novel approach is suggested to design the cryogenically cooled low-noise amplifiers for the frequency range 0.5 to 4 GHz with emphasis on noise and stability performances. When cooled to 20-80 Kelvin, the noise temperature of the represented devices, being about a few degrees Kelvin, shows to be the best for the devices on commercially available PHEMTs being close to those using special-purpose cooled InP-HEMTs. The major scope of application for such devices are radio astronomy receivers where these amplifiers can be used either as input or IF ones.