Cryogenic CMOS Active Mixer Employing Transformer-Based Current-Bleeding Technique

This brief presents a cryogenic complementary metal-oxide-semiconductor (CMOS) active mixer designed to achieve low-noise and low-power characteristics at cryogenic temperatures. The proposed design employs a transformer-based current-bleeding (CB) technique that further enhances both the conversion gain and noise performance of the mixer when compared to the conventional CB approaches. Implemented as a double-balanced active mixer, the design was fabricated using a 65-nm CMOS process and validated across the 4–8 GHz frequency range under both cryogenic and room temperatures.