An 11GHz 8-core Series Resonance CMOS VCO with Scalable Ring-coupling Scheme Achieving Phase Noise of-136.8dBc/Hz at 1 MHz Offset

This paper proposes X-band multi-path ringcoupling dual-core and hybrid-coupling octa-core series resonance VCOs to achieve ultra-low phase noise. The scalable multi-path ring-cross-coupling scheme is suitable for multi-core intrinsic oscillation, through various ring paths in oscillators with multiple resonance cells. The tuning range and FoM variation of the VCO are further improved. Prototyped in a 65-nm CMOS process, the 8-core 16-coil series resonance VCO achieves - 136.8dBc/H at 1MHz offset frequency and -157.2 dBc/Hz at 10MHz offset from the carrier frequency of 11.02 GHz. To the best knowledge of the authors, this work reports the VCO with the lowest phase noise in CMOS technology in open literature so far.