A 21–27 GHz LNA-Mixer in a 180 nm SiGe BiCMOS Process

This article presents a 21–27 GHz LNA-Mixer used for radar receiver in a 180 nm SiGe BiCMOS process under 1.8 V voltage supply. The LNA incorporates a single-stage cascode topology with capacitive feedback and neutralized capacitors to balance gain, noise, and linearity. Considering the low voltage supply, the mixer adopts a passive double-balanced structure, down-converting the RF signal to 1 MHz. A transformer is utilized for the interstage impedance matching between LNA and Mixer. The DC biasing condition is provided by a Proportional To Absolute Temperature (PTAT) current source. Designed at the center frequency 24 GHz, the proposed LNA-Mixer achieves −20.9 dBm IP1dB, 31.3 dB voltage gain, 4.1 dB noise figure under 36.0 mW power consumption.