Low Phase Noise VCO using Novel Harmonic Control Circuit Based on Quad-band Composite Right/Left-handed Transmission Line

In this paper,a novel Voltage-Controlled Oscillator (VCO) using the harmonic control circuit based on the quad-band Composite Right/Left-Handed (CRLH) Transmission Line (TL) is presented to reduce the phase noise without the reduction of the frequency tuning range and miniaturizing the circuit size.The phase noise has been reduced by the quad-band harmonic control circuit which has the short impedance for the second- and third- and fourthand fifth-harmonic components.The CRLH TL with two Left- Handed (LH) (backward) and two Right-Handed (RH) (forward) pass hands are used to design the quad-band harmonic control circuit.The highQ resonator has heen used to reduce the phase noise,but it has the problem of the frequency tuning range reduction.However,the frequency tuning range of the proposed VCO has not reduced because the phase noise has reduced without the high-Q resonator.The miniaturization of the circuit size is achieved by using the quad-band CRLH TL instead of the conventional RH TL.The phase noise of VCO is -124.43～-122.67 dBc/Hz at 100 kHz in the tuning range of 5.729～5.934 GHz.