A 22.4-to-40.6-GHz Multi-Ratio Injection-Locked Frequency Multiplier with 57.7-dBc Harmonic Rejection

This paper presents a multi-ratio injection-locked frequency multiplier (MR-ILFM) targeting millimeter-wave (mm-wave) multiband 5G communications. With only low-frequency narrow-bandwidth input signals required, difficulties in generating low-phase-noise mm-wave wideband signals can be solved by switching the multiplication ratio of the MR-ILFM for bandwidth extension. Issues on suppressing undesired harmonics in multi-ratio multipliers are considered, and an impulse sensitivity function (ISF) based analysis is adopted to show the superior harmonic rejection properties of injection locking. With the use of injection locking and ILFM cascading, the harmonic rejection reaches to 57.7 dBc. The proposed MR-ILFM has × 5 and ×7 multiplication ratio, and 24 switchable frequency bands for ratio switching. Fabricated in 65 nm CMOS process, the MR-ILFM consumes 10.0-mW power and can operate from 22.4 to 40.6 GHz with 4.3-to-5.8-GHz inputs.