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° and 2.1° before and after calibration, respectively.

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IEEE Transactions on Microwave Theory and Techniques
Department of Electronics

Soliman, Y. (Yasser), & Mason, R. (2010). Application of subharmonic injection locking of LC oscillators to LO-based phase-shifting phased-array architectures. In IEEE Transactions on Microwave Theory and Techniques (Vol. 58, pp. 3475–3484). doi:10.1109/TMTT.2010.2081570