A 0.065 mm² Inductive Coupling Based Dual Core mm-Wave VCO With 183 dBc/Hz FoMT

This paper presents a novel dual core inductive coupling based area efficient mm-Wave voltage controlled oscillator fabricated in 40 nm CMOS process for K-band applications. New inductive coupling techniques have been implemented for resonant mode switching between two VCO cores, each having an inductive divider based LC tank. Detailed mathematical analysis has been developed on the effect of various higher-order harmonics on waveform symmetry. Simulations are performed to explore the time-variance property of various noise-contributing elements in the VCO. The VCO fabricated in 40 nm CMOS process without an ultra-thick top metal layer occupies a core area of 0.065 mm 2. The proposed layout floorplan reduces the active area requirement of multi-core VCO. The measured frequency tuning range is from 21.6 to 25.5 GHz. The proposed dual core VCO shows measured phase noise of -112 dBc/Hz and -115 dBc/Hz at 3 MHz and 10 MHz offset respectively for a center frequency of 22.5 GHz in 40 nm CMOS process. The VCO achieves a measured FoMT of 183 dBc/Hz at an offset of 3 MHz for a power consumption of 18.4 mA and a tuning range of
$> 16 \%$
demonstrating a practical solution.