A Wide Tuning Range Millimeter Wave CMOS LCVCO with Linearized Coarse Tuning Characteristics

A folded feed line structure is proposed to realize a millimeter-wave wide tuning range LC voltage-controlled oscillator (VCO) with linearized coarse tuning characteristics. A 5-bit segmented capacitor C-DAC is implemented with the proposed folded feed line structure on 45nm CMOS SOI technology and verified at 60 GHz. A combination of post layout and electromagnetic (EM) simulation results show that this technique reduces the fixed capacitance of the feed line parasitic by 47% at 60 GHz and improves the quality factor of the C-DAC by 57% compared to the conventional feed line structure. Moreover, the maximum error on the regularity of the coarse tuning C-DAC is reduced by S4% and the VCO tuning range is extended by 21% compared to the conventional structure.