A 47.6–71.0-GHz 65-nm CMOS VCO Based on Magnetically Coupled $\pi$ -Type LC Network

A wide tuning range millimeter-wave voltage-controlled oscillator (VCO) based on a magnetically coupled π-type LC network in 65-nm CMOS is proposed. By configuring the switched negative-resistance unit, the VCO can oscillate at the even mode or the odd mode of the magnetically coupled π-type LC network, thus the tuning range is widened without introducing the switch loss into the resonator. The proposed VCO achieves a measured continuous tuning range of 39%, from 47.6 to 71.0 GHz. The measured phase noise for a 47.6-GHz carrier at the even mode and 56.2-GHz carrier at the odd mode are -110.3 and -107.3 dBc/Hz at 10-MHz offset with a corresponding FOMT of -185.5 and -183.9 dBc/Hz, respectively. The measured phase noise in the whole frequency tuning range varies from -101.7 to -113.4 dBc/Hz at 10-MHz offset, while the corresponding figure-of-merit (FOM) and FOMT vary from -167.8 to -179.0 dB and -179.6 to 190.6 dB, respectively. The VCO core consumes 8.9-10.4-mA current from 1.0-V power supply and 320 × 230 μm ² die area.