Application of Subharmonic Injection Locking of LC Oscillators to LO-Based Phase-Shifting Phased-Array Architectures

摘要

A ninth-subharmonic injection-locking scheme is proposed for local oscillator (LO) phase-shifting-based phased-array architectures operating in the ISM band at 24 GHz. The presented architecture employs a phase-shifter at the ninth subharmonic, a high-speed regenerative comparator, and a negative-$g_{m}$ oscillator to synthesize multiple phases of ninth-harmonic LO signals from a 2.41-GHz reference at the destination and in close proximity to the RF/millimeter-wave front-end mixers with first LO at 21.69 GHz. A digital phase-shift calibration technique is discussed. The reported LO phase-shifting and synthesis scheme is implemented in IBM's 130-nm CMOS technology and consumes a total of 32 mA per LO element from a 1.2-V supply. The injection-locked oscillators have a phase-noise performance of $-$ 107.17 dBc/Hz at 1-MHz offset from 21.51 GHz. The maximum phase-shift error at 21.69 GHz is 9.86$^{circ}$ and 2.1$^{circ}$ before and after calibration, respectively.