Electromagnetic response of the split-ring resonator placed inside a waveguide

The EM response of split ring resonators, conventionally employed to design the left-handed metamaterials, was studied by modeling the behavior of one ring located in a standard waveguide. It was shown that, besides the expected half and full-wavelength resonances, an additional resonance is excited in the SRR at an intermediate frequency due to coupling between the SRR and the waveguide. This resonance supports longitudinal mode in the waveguide and magnetic dipole-type fields near the SRR. While the response of the SRR at the first resonance can be described by negative permeability, the full-wavelength resonance features negative permittivity and the intermediate resonance exhibits more complex behaviors of the constitutive parameters. The properties of this resonance could be used to design novel metamaterials.