7GHz voltage control ring oscillator for UWB applications

This paper presents the design of a low-power 7 GHz two-stage VCO for UWB systems using a 0.13 ¿m CMOS technology with supply voltage of 1.2 V. Fully differential structure is utilized to achieve high substrate noise rejection and a new formula is derived which accurately estimates the VCO output frequency as a function of control voltage. The VCO has very large tuning range (4.22 GHz), covering the output frequency from 3.41 GHz to 7.63 GHz with control voltages of 0.1 V to 1.2 V. The power dissipation is about 7.48 mW and 4.39 mW when VCO operates at the highest and lowest frequency, respectively. The simulation result of phase noise is -84.87 dBc/Hz at 1 MHz frequency offset from the center frequency of 7 GHz.