Design and Analysis of CMOS Subharmonic Injection-Locked Frequency Triplers

K- and V-band CMOS differential subharmonic injection-locked frequency triplers (ILFTs) are proposed, analyzed, and designed. Based on the proposed ILFT structure, models for the injection-locking range and the output phase noise are developed. A K-band ILFT is designed and fabricated using 0.18-m standard CMOS technology. The measured injection-locking range is 1092 MHz with a dc power consumption of 0.45 mW and an input injection power of 4 dBm. The harmonic rejection ratios are 22.65, 30.58, 29.29, 40.35 dBc for the first, second, fourth, and fifth harmonics, respectively. The total injection-locking range of the -band ILFT can achieve 3915 MHz when the varactors are used and the dc power consumption is increased to 2.95 mW. A -band ILFT is also designed and fabricated using 0.13-m standard CMOS technology. The measured injection-locking range is 1422 MHz with 1.86-mW dc power consumption and 6-dBm input injection power. The injection-locking range of the proposed ILFT is similar to the tuning range of a conventional varactor-tuned bulk-CMOS voltage-controlled oscillator (VCO). Moreover, the proposed ILFT has a greater output power and a lower dc power consumption level than a VCO. As a result, it is feasible to use the proposed ILFT in low-power millimeter-wave synthesizers.