Calculating Periodic Structures Based on Ideally Conductive Squares

The applicability of the method for solving the problem of diffraction by resistive gratings, based on solving the problem of exciting the Floquet channel by current elements to the calculation of structures with planar ideal gratings, is shown. A quasi-static approximation formula is obtained for the effective dielectric constant of a flat single-layer grating based on perfectly conducting squares. Comparative calculations of the reflection coefficient by diffraction and quasi-static methods for single-layer and two-layer gratings with dielectric layers are carried out.