Calibration of phase and gain mismatches in Weaver image-reject receiver

A modified image-reject Weaver architecture is presented. The design automatically calibrates for phase and gain mismatches that limit the performance of image-reject receivers. On-line or off-line calibrations are possible without using any calibrating tone. An experimental CMOS prototype RF front-end operating at 1.8 GHz achieves an image rejection ratio of 59 dB using on-line calibration. The design was fabricated in a 0.35-μm CMOS process and dissipates 160 mW from a 3-V supply during on-line calibration, and 95 mW during normal receiving. The die area is 4 mm².