A 24-GHz 90-nm CMOS beamforming receiver front-end with analog baseband phase rotation

A 24 GHz 2-path beamforming receiver front-end in 90 nm CMOS is presented. It consists of two direct conversion front-ends followed by a baseband block performing phase rotation and signal combination. The baseband phase rotation is performed by combining the quadrature phases using digitally controlled weights, achieving a phase resolution of 11 degrees. From each of the two inputs the front-end measures; a conversion gain of 13 dB, NF <; 9 dB, ICP_1db = -20.5dBm, IIP3 = -7.5dBm, LO-RF isolation 48dB, all at a power consumption of 33.6mW from a 1.2 V supply. The chip area is 1400 × 850 μm², including pads, of which the phase rotation block occupies 400 × 100 μm².