A 35.2–51.4GHz Frequency-Tracking Injection-Locked Frequency Tripler Achieving >28.5dBc Harmonic Rejection Ratios, -7.3dBm Output Power, and 4.3dB Output Power Variation

This paper presents a frequency-tracking injection-locked frequency tripler (ILFT) featuring wide locking range (LR), high harmonic rejection ratios (HRRs), high output magnitude, and low output magnitude variations. The proposed ILFT utilizes a single-ended injection combined with an amplitude detection method to enhance frequency tracking bandwidth. A dual-core topology is also implemented to improve even harmonic rejection and to provide differential output signals. Fabricated in a 28-nm CMOS process, the ILFT measures an LR of 37.5% from 35.2 to 51.4GHz while achieving an output power of -7.3dBm with power variation of 4.3dB and HRR₁ and HRR₂ of 45.2–52dBc and 28.5–46.5dBc, respectively. The total power consumption of the dual-core frequency-tracking ILFT is 11.6mW.