Low Phase-Noise and Strong Start-Up Condition Voltage Controlled Oscillator for K Band Applications

This paper presents a voltage controlled oscillator (VCO) based on a cross-coupled pair and Colpitts structures for K-band applications. By employing cross-coupled pair and Colpitts structures, the dc power consumption and phase noise was reduced. By using inductors between cross-coupled pair and Colpitts structures, the effective transconductance was enhanced and robust the start-up condition. In order to cover a wide frequency tuning range, a capacitor bank was used. The VCO has been designed and simulated in TSMC 0.18 µm CMOS technology. Simulation results showed that the simulated phase noise of center frequency (24.25 GHz), at 1-MHz offset frequency is-120 dBc/Hz and the figure of merit is -195.67 dBc/Hz. The covering frequency range and tuning range of this VCO are 1.4 GHz and 5.7%, respectively. The occupied area of the layout is 335 µ2m and the power consumption of this VCO was 15.92 mW from 1.5 V supply voltage.