Microstrip Square Open Loop Metamaterial Resonator and Rat Race Coupler for Low Phase Noise Push-Push VCO

Abstract

In this paper, a novel low phase noise voltage-controlled oscillator (VCO) using metamaterial structure and rat race coupler is presented for reducing the phase noise without the reduction of the frequency tuning range. The me- tamaterial structure has been realized by microstrip square open loop double split ring resonator (SRR). The rat race coupler shows slightly higher transmission compared to a Wilkinson combiner and is, therefore, used instead to improve the performances of VCO. By providing these unique modifications, the proposed push-push VCO has a phase noise of —126.30～—124.83 dBc/Hz at 100 kHz in the tuning range of 5.672～5.800 GHz.