2009 Volume E92.C Issue 9 Pages 1226-1229
This letter presents a new quadrature voltage-controlled oscillator (QVCO) consisting of two n-core Colpitts voltage-controlled oscillators (VCOs) with a tail inductor. The VCOs are used as a single-ended injected injection-locked frequency divider (ILFD). The output of the tail inductor in one ILFD is injected into the injection node in the other ILFD and vice versa. The proposed QVCO has been implemented in the 0.18μm CMOS technology. At the supply voltage of 1.0V, the power consumption is 1.8mW. The free-running frequency is tunable from 4.68GHz to 5.03GHz as the tuning voltage is varied from 0.0V to 1.8V. The measured phase noise is -113.58dBc/Hz at the 1MHz frequency offset from the oscillation frequency of 5.03GHz and the figure of merit (FOM) of the QVCO is -185.06dBc/Hz.
