Low phase noise VCO using output matching network based on novel harmonic control circuit

We have realized the novel VCO using the output matching network based on the proposed harmonic control circuit to reduce the phase noise without the reduction of the frequency tuning range. The proposed harmonic control circuit has the short impedances for the second- and third-harmonics, which has suppressed the phase noise. The frequency tuning range of the proposed VCO has not been reduced because the phase noise has been reduced without the high-Q resonator. The microstrip square open loop multiple split ring resonator has been used with the proposed harmonic control circuit for better phase noise property.