A 30-GHz class-F23 oscillator in 28nm CMOS using harmonic extraction and achieving 120 kHz 1/f 3 corner

This paper presents a mmW frequency generation stage aimed at minimizing phase noise via waveform shaping and harmonic extraction while suppressing flicker noise upconversion via proper harmonic terminations. A second-harmonic tank resonance is assisted by a proposed embedded decoupling capacitor inside a transformer for shortest and well controlled common-mode current return path. Class-F operation with third-harmonic boosting and extraction techniques allow maintaining high quality factor of a 10 GHz tank at the 30 GHz frequency generation while providing implicit divide-by-3 functionality. The proposed 27.3–31.2 GHz oscillator is implemented in 28-nm CMOS. It achieves phase noise of −106 dBc/Hz at 1-MHz offset and figure-of-merit (FoM) of −184 dB at 27.3GHz. Its flicker phase-noise (1/f 3 ) corner of 120 kHz is an order-of-magnitude better than currently achievable at mmW.