Electromagnetic Detection and Identification of Perturbed Wire Resonators

The resonances of metal wire resonators may change due to a localized variation of the surrounding dielectric, coupling to nearby resonators, or the introduction of bends. We used shifts in the resonant frequencies to detect and identify perturbed wire resonators. In this paper, we present measurements, a perturbation model based on a lumped-element circuit, and full-wave simulations of perturbed resonators. Resonances of four resonators with different structures and perturbations were excited with near-field probes, and the variations of normalized resonant frequency with perturbation position were shown to agree with the results obtained from full-wave simulations. The experimental and simulated data match the perturbation theory, which suggests the feasibility of identifying perturbed metal resonators by exciting and detecting their resonances.