Transformer-based varactor-less 96GHz–110GHz VCO and 89GHz–101GHz QVCO in 65nm CMOS

This paper presents a transformer-based magnetic-tuning technique to achieve wide frequency tuning range and low power consumption for W-band oscillators without varactors. Fabricated in a 65-nm CMOS process, a dual-band VCO prototype measures frequency tuning range of 14.3% from 95.7 GHz to 110.5 GHz while consuming 6.2 mW, corresponding to a peak FOMt of −181.7 dBc/Hz at 10-MHz offset. In addition, a dual-band transformer coupling quadrature VCO (TC-QVCO) prototype achieves frequency tuning range of 12.1% from 89.4 GHz to 100.9 GHz while consuming 7.6 mW, corresponding to a peak FOMt of −178.8 dBc/Hz at 10-MHz offset. The measured quadrature phase error is less than 2.6° over the entire frequency range.