A frequency multiplication based LO phase shifting technique for phased-array architectures

A frequency multiplication based LO phase shifting technique is presented for use in phased-array front end architectures operating in the ISM band at 24GHz. The presented architecture employs a two-stage phase shifter, a high-speed comparator and a Q-enhanced tuned amplifier to synthesize 18GHz tones from a 2GHz reference. The synthesized tones are used to injection lock 18GHz LC-oscillators in close proximity to the RF/mm-w front-ends in a phased-array system. A digital means for phase shift calibration is discussed. Implemented in IBM's 120 nm CMOS technology, the proposed architecture consumes 14.2mW from a 1.2V supply. The oscillator core consumes 3.7mW. The maximum phase shift errors at 18GHz is 5° and 0.79° before and after calibration, respectively.