Sensitivity Enhancement of Microwave Split-Ring-Resonator Sensors

Split-ring resonators (SRRs) are structurally studied to optimize the sensitivity of planar microwave sensors in terms of frequency variation sensitivity. An indirect excitation profile integrated with symmetrically orientated split-gap SRRs is developed for sensitivity enhancement. The electromagnetic (EM) fields are manipulated to reinforce each other in favor of a fringing EM fields enhancement in the new SRR sensor (SRRS) topology. The intensified fringing EM fields are expected to further interact with a surrounding medium resulting in sensitivity improvement. Moreover, SRRs are examined with a direct excitation profile to enhance the sensitivity of the sensors. The experimental results confirm sensitivity enhancement by the ratios of 2.04:1 and 1.98:1 for the first and second higher mode resonances, respectively.