4–12- and 25–34-GHz Cryogenic mHEMT MMIC Low-Noise Amplifiers.

In this paper, monolithic microwave integrated circuit (MMIC) broadband low-noise amplifiers (LNAs) for cryogenic applications based on a 100-nm metamorphic high-electron mobility transistor (mHEMT) technology in combination with grounded coplanar waveguide are reported. A three-stage LNA, operating in 4–12 GHz and cooled to 15 K exhibits an associated gain of 31.5 dB \pm 1.8 dB and average noise temperature of 5.3 K (NF=0.079\ \ dB) with a low power dissipation of 8 mW. Additionally another three-stage LNA 25–34 GHz cooled to 15 K has demonstrated a flat gain of 24.2 dB \pm 0.4 dB with 15.2 K (NF=0.22\ \ dB), average noise temperature, with a very low power dissipation of 2.8 mW on chip. The mHEMT-based LNA MMICs have demonstrated excellent noise characteristics at cryogenic temperatures for their use in radio-astronomy applications. [ABSTRACT FROM AUTHOR]