Resonant plane wave scattering by a grating of rectangular bars and a metamaterial

Research into the special features of the wave processes in open structures (open waveguides and resonators, diffraction gratings) completed with metamaterials [1, 2] attracts considerable interest and both allows formulation of new physical principles of electromagnetic wave generation, amplification and channeling and promotes adoption of such specific properties of the electromagnetic field in these structures as Doppler shift inversion, changes of Cerenkov radiation direction, etc. [1]. An important stage in these studies is the research into resonant effects arising during the plane monochromatic electromagnetic wave diffraction by single-periodic structures with metamaterials [3]. In this report, resonant phenomena occurring in the H-polarized plane wave scattering by a grating are discussed. The grating is made of rectangular perfectly conducting bars, the slots are filled with a metamaterial, its effective permittivity depending on the excitation wave frequency. In a frequency region where the real part of the effective permittivity of the metamaterial takes on negative values, a denumerable set of frequencies with a finite accumulation point has been found at which the reflection coefficient comes close to a unit. This anomalous reflection is caused by the excitation of specific oscillations localized on the metamaterial-vacuum interface.