Microstrip Square Open-Loop Multiple Split-Ring Resonator for Low-Phase-Noise VCO

In this paper, we present a novel voltage-controlled oscillator (VCO) using the microstrip square open-loop multiple split-ring resonator for reducing the phase noise of VCO. We realize the microstrip square open-loop multiple split-ring resonator by combining the multiple split-ring resonator with the microstrip square open-loop structure. Compared with the conventional microstrip square open-loop resonator, the microstrip square open-loop multiple split-ring resonator has strong coupling between the microstrips of the open-loops with the multiple split-ring resonators, which makes for a high Q value of the resonator. The phase noise and the tuning range of the proposed VCO are -124.5 to -122.0 dBc/Hz at 100 kHz and 5.746 to 5.84 GHz. The figure-of-merit (FOM) of this VCO is -203.96 to -201.6 dBc/Hz at 100 kHz in the same tuning range.