Using metamaterial resonators for controlling surface wave modes in an open waveguide

Based on the properties of surface wave modes in dielectric slab waveguides, it is shown that the cutoff frequencies of the surface wave modes can be obtained from the zeroes of the reflection coefficient at wavenumbers close to the light line. Afterwards, a surface wave periodic structure is analyzed by the method of excitation of eigenmodes. By considering the field distribution of the surface wave modes of the open waveguide structure, the unit cells are loaded by appropriate metamaterial resonators. The metamaterial resonators introduce a new surface wave mode propagating at frequencies below their resonant frequency while the eigenmodes of the guided structure are not strongly affected. This method can be employed to obtain an arbitrary frequency band for near-field imaging applications.