A Dual-Injection Technique for mm-Wave Injection-Locked Frequency Multipliers

This article presents a locking-range extension technique for injection-locked frequency multipliers used in millimeter-wave (mm-wave) local oscillator (LO) generation. A conventional parallel injection is combined with class-D tail switching, achieving a significant extension of the locking range. Theoretical insights into the effectiveness of the proposed technique, and comparison with conventional injection techniques, are provided. A 28-nm CMOS frequency tripler prototype achieves 57–74 GHz operation with >300 mV differential zero-peak (diff,0-pk) output swing and 11 mW power consumption, without using tuning elements.