A Dual-Band CMOS Voltage-Controlled Oscillator Implemented With Dual-Resonance LC Tank

A new fully integrated, dual-band CMOS voltage controlled oscillator (VCO) is presented. The VCO is composed of n-core cross-coupled Colpitts VCOs and was implemented in 0.18 $mu$m CMOS technology with 0.8 V supply voltage. The circuit allows the VCO to operate at two resonant frequencies with a common LC tank. The VCO has two control inputs, one for continuous control of the output frequency and one for band switching. This VCO is configured with 5 GHz and 12 GHz frequency bands with differential outputs. The dual-band VCO operates in 4.78–5.19 GHz and 12.19–12.61 GHz. The phase noises of the VCO operating at 5.11 and 12.2 GHz are ${-}117.16$ dBc/Hz and ${-}112.15$ dBc/Hz at 1 MHz offset, respectively, while the VCO draws 3.2/2.72 mA and 2.56/2.18 mW consumption at low/high frequency band from a 0.8 V supply.