A 180-nm X-Band Cryogenic CMOS LNA

This letter presents the measurement results of a 180-nm complementary metal-oxide-semiconductor (CMOS) $X$ -band low-noise amplifier (LNA) at both 77 and 300 K. The designed LNA provides $S_{11}$ and $S_{22}$ below -10 dB at both temperatures within 6.4-7.4 GHz band. At 300 K, the voltage gain of the designed LNA is higher than 12.5 dB, and it provides an average noise temperature of 275 K, as well as -1 dBm IIP3. At 77 K, the LNA has approximately an 18-dB voltage gain, 78-K noise figure (NF), and -3 dBm IIP3. The presented work is the first implemented $X$ -band cryogenic CMOS LNA in the literature.