A subharmonic injection-locking scheme for LO phase shifting phased-array architectures

A ninth subharmonic injection locking scheme is proposed for LO phase shifting based phased-array architectures operating in the ISM band at 24 GHz. The presented architecture employs a two stage phase shifter, a limiter and a Q-enhanced tuned amplifier to synthesize multiple phases of ninth-harmonic tones from a 2 GHz reference at the destination and in close proximity to the RF/mm-w injection-locked oscillators operating at 18 GHz. A digital phase shift calibration technique is also discussed. The reported LO phase shifting and synthesis scheme is implemented in IBM´s 120 nm CMOS technology and consumes a total of 11.8 mW from a 1.2 V supply. The oscillator core consumes a 3.7 mW. The maximum phase shift error at 18 GHz is 4.29° and 0.42° before and after calibration, respectively.