A low noise Ka-band amplifier for radio astronomy

Abstract

We present the designs for and the results of a prototype cryogenic Ka-band low noise amplifier (LNA), that is based on the hybridization of microwave integrated circuits (MICs) and monolithic microwave integrated circuits (MMICs). The resulting transistor plus MMIC (T+MMIC) 5 stage LNA, has a peak gain of 52dB, a minimum noise temperature of 12K at an ambient temperature of ≈23K, and a 20% bandwidth of 27-33GHz. We outline the background behind the LNA, our measurement process, the LNA's performance, our future development plans and discuss the possible advantages that this amplifier layout may offer.