A 28.4-to-39.2 GHz Low-Power Injection-Locked Frequency Quadrupler With Reconfigurable Pre-Filter-Amplifier

In this paper, a 28.4 to 39.2 GHz injection-locked frequency quadrupler (ILFQ) is fabricated in a 65nm CMOS process. A reconfigurable pre-filter-amplifier (RPFA) structure is proposed to pre-process the output current of the harmonic generator. By switching between two modes, the RPFA effectively filters out the undesired harmonics and amplifies the desired 4th harmonic. Therefore, both the harmonic rejection and locking range of the ILFQ are improved. In addition, a load tank based on a three-coil coupled transformer and an impedance-boosting transformer is designed to further extend the locking range, increase the output power, and reduce the DC power consumption. The measured results show that the proposed ILFQ achieves a 31.9% locking range (28.4 GHz to 39.2 GHz). Across the whole locking range, the measured 1st/2nd/3rd harmonic rejection ratio (HRR) is better than 42.4/37.4/15 dBc, respectively. Within the range of 28.4 to 36.2 GHz, >29 dBc 1st/2nd/3rd HRR is achieved. The measured maximum DC power consumption is 13.3 mW.