Broadband VCO using tunable metamaterial transmission line with varactor-loaded split-ring resonator

Abstract

In this paper, the broadband voltage-controlled oscillator (VCO) using tunable metamaterial transmission line with varactor-loaded split-ring resonator (VLSRR) is presented. It is demonstrated that VLSRR coupled to microstrip line can lead to metamaterial transmission line with tuning capability. The negative effective permeability is provided by the VLSRR in a narrow band above the resonant frequency. The bias of VLSRR is controlled by the varactor diodes. The phase noise of VCO is -108.84 ∼ -106.84 dBc/Hz @ 100 kHz in the tuning range, 5.407 ∼ 5.84 GHz. The figure of merit (FOM) called power-frequency-tuning-normalized (PFTN) is 20.144 dB.