Design of a CMOS Quadrature Mixer with 44dB Image Rejection Ratio

This paper presents the design and implementation of a high-image rejection quadrature mixer optimized for zero-IF radar receivers, fabricated using 28nm CMOS technology. The proposed mixer is characterized by a broad phase calibration range and high calibration precision. The architecture integrates a low-noise transconductance amplifier, a Gilbert cell, a transimpedance amplifier, and a phase calibration circuit. Simulation results demonstrate that the quadrature mixer achieves a phase calibration range of ±4° with a calibration accuracy of 0.2°. The mixer exhibits a conversion gain exceeding 27.6 dB, a noise figure below 2.7 dB, a 1 dB compression point of -18.87 dBm, and an image rejection ratio exceeding 44 dB, for RF and local oscillator signals ranging from 0.8 to 6 GHz. These results underscore the mixer's superior image rejection performance.