A Cryogenic Four-Channel C-Band Low-Noise Amplifier MMIC in 50-nm Metamorphic High-Electron-Mobility-Transistor Technology

This paper reports on a four-channel C-band (4 – 8 GHz) low-noise amplifier (LNA) monolithic microwave integrated circuit (MMIC) designed for cryogenic ultra-low-noise operation. Both, a single and a four-channel version of the MMIC are presented proofing that a high level of integration can be achieved. This makes monolithic solutions well suited for large cryogenic systems, such as radio-astronomical phased arrays or future superconducting quantum computers. The presented two-stage design provides an in-band average effective input noise temperature (Te) of 2.7K when cooled to 10K with an average small-signal gain of 31 dB at optimal noise bias (7.78mW of dc-power). The power consumption can be reduced to 0.77mW with a small-signal gain of 23.7 dB and an average Te of 3.77 K.