A 28-/39-GHz CMOS LO Generator With Implicit Second and Third Harmonic Extraction Techniques for Multiband 5G mm-Wave Applications

This work presents a low-phase-noise millimeter-wave (mm-wave) local oscillator (LO) generator employing implicit second and third harmonic extraction techniques. The proposed harmonic extraction approach effectively improves phase noise performance in the mm-wave frequency range while maintaining the wide tuning range. Fabricated in a 65-nm CMOS process, the proposed LO generator achieves a wide frequency tuning range from 22 to 29.1 and 33 to 43.6 GHz. It consumes 7.4 and 8.8 mW for the second and third harmonic outputs, respectively. The second harmonic output achieves a phase noise of −131.1 dBc/Hz at a 10-MHz offset from a carrier frequency of 25.1 GHz, corresponding to a peak figure of merit (FoM) of 190.4 dBc/Hz. For the third harmonic output at 33.6 GHz, the phase noise is −128.4 dBc/Hz at a 10-MHz offset, resulting in a peak FoM of 189.5 dBc/Hz.