Spectral method in the problem of wave diffraction by a knife grating

The scattered field is determined for a grating consisting of a number of ideally conducting ribbons parallel to the axis in the case of the incidence of an H-polarized electromagnetic wave. The problem is solved by the spectral method and the inversion of the static part of the operator for diffraction by a ribbon. As an example, a calculation is made of the dispersion dependences of the amplitudes of the fundamental mode and the higher transmitted-field harmonics.