Novel design of a CMOS voltage-controlled oscillator with low phase noise and large tuning range

Voltage-controlled oscillator (VCO) with large tuning range and low phase noise is implemented by using 0.18 μ m CMOS process. Active inductor and LC filter at tail currents were used to enlarge the tuning range and to improve phase noise of CMOS VCO. Accumulation varactors are used to widen frequency tuning. The tuning range and phase noise were measured as 29% and -120 dBc/Hz at 1 MHz offset, respectively. In addition, the output frequency is between 2.61 GHz and 3.14 GHz for 1.8 V power supplies.