Low Phase Noise VCO using microstrip square open loop split ring resonator

In this paper, a novel VCO using the microstrip square OLSRR is presented to reduce the phase noise. We have recently obtained that the Q value increases by combining the square- shaped SRRs with the microstrip square open loop structure due to higher coupling coefficient value than the other resonator topologies. Compared with the microstrip square open loop resonator, the microstrip square OLSRR has the larger coupling coefficient value, which makes a higher Q value, and has reduced the phase noise of VCO. The proposed VCO has the phase noise of -120 ~ -117.17 dBc/Hz @ 100 kHz in the tuning range, 5.746 ~ 5.892 GHz. The FOM of this VCO is -200.33 dBc/Hz at 5.746 GHz.