A 12-16.3-GHz 197.7-dBc/Hz-FOMT Harmonic-Shaping VCO Using Enhanced Common-Mode Resonance Expansion Based on a Triple-Tank Coupled Resonator

This paper presents a wideband, low-phase-noise harmonic-shaping voltage-controlled oscillator (VCO) featuring a novel common-mode resonance extension technique. A triple-tank coupled resonator (TTCR) is employed to synthesize a high-order common-mode (CM) resonance. By closely separating the poles of the TTCR, CM impedance fluctuations and deep notches are effectively mitigated across the wide frequency range. This mechanism significantly expands the CM high-impedance bandwidth, thereby eliminating manual tuning to align the second-harmonic resonance. Consequently, the VCO maintains a highly symmetric oscillation waveform and a near-zero DC component of the effective Impulse Sensitivity Function (ISF), which intrinsically suppresses flicker noise up-conversion. Fabricated in a 28-nm CMOS process, the VCO occupies a core area of only 0.056 mm² and covers a tuning range of 12–16.3 GHz (30.4%). It achieves a remarkable 1/f3 phase-noise corner of 130 kHz. The measured phase noise is -113.3 dBc/Hz at 1-MHz offset, resulting in a FoMT of 197.7 dBc/Hz.