Resonant cell with open entrance on the base of dielectric plate on a metal substrate
Possibility of converting the energy of an incident electromagnetic wave to the energy of a surface wave in a dielectric plate on a metal substrate has been confirmed through numerical simulation. To transfer energy between waves of different structures, a diffraction grating placed on the surface of the plate is used. Energy is retained in the plate through the formation of a surface wave resonator by introducing aflush metal walls along the plate’s ends. Thus, the resonant cell with open entrance has been suggested - the energy enters the cell through the whole lit surface of the plate. It is assumed that the dielectric has small losses, and the diffraction grating on its surface consists of the identical bars, which are made of the same dielectric and have small cross section. The resonance in the form of sharp increase of the standing wave amplitude inside the plate, compared to the incident wave amplitude, and correspondingly increase of the incident wave’s energy absorption by the plate takes place at some grating periods. The external manifestation of resonance is a decrease of specular scattering from the plate: the observed decrease of plate’s RCS in the ray reflection direction was from several times to more than three orders of magnitude under different conditions. Stability of numerical solution of the problem of diffraction on the suggested cell follows from the observed smooth variation of the condition number in the vicinity of even the deepest plate’s resonant RCS reduction. Efficiency of surface wave generation by diffraction gratings of different types or by arranging other periodical inhomogeneities on the surface or within the volume of dielectric can be compared according to the depth of resonance.