Cryogenic Operation of a Millimeter-Wave SiGe BiCMOS Low-Noise Amplifier

In this letter, we report the design and characterization of a cryogenically cooled silicon germanium (SiGe) low-noise amplifier (LNA) covering a frequency range from 50 to 70 GHz. The amplifier was fabricated in 0.13-mu m SiGe BiCMOS technology. At 20 K, the LNA showed stable operation and an average noise figure (NF) of 2.2 dB (191 K) in the 52-65-GHz frequency band. This means 4.4 times improvement compared to the noise temperature at room temperature conditions for the same frequency band. When biased to lowest noise operation at cryogenic conditions of 20 K, the measured small signal gain was 18.5 dB at 60 GHz, while the consumed power was 6.3 mW. According to the authors' knowledge, this is the first report on cryogenic millimeter-wave SiGe LNA and the lowest NF measured for a SiGe LNA in the 50-70-GHz frequency range.