A Multi-band CMOS VCO Based on Triple-coil Inductors

This paper presents a small-area and multiband voltage-controlled oscillator (VCO) using triple-coil inductors which can be used for wideband frequency synthesizer. A wide tuning range generally requires a large chip area. By regulating the coupling coefficient of the triple-coil inductors and parasitic capacitance of cross-couple pair, the triple-mode operation of VCO can be stably implemented. Notably, the triple-coil inductor can be realized within the same area as a single inductor. The VCO exhibits a wide tuning range from 6.6 GHz to 13.1 GHz, and a phase noise lower than -100 dBc/Hz at 1 MHz offset over the entire tuning range.