Equivalent boundary conditions for the electromagnetic field on the surface of a periodic grating of resistive strips

The present work is aimed at formulating equivalent boundary conditions for the electromagnetic field on the surface of a periodic grating of resistive strips valid for arbitrary incident fields. It is assumed that the period of the grating is much smaller than the wavelength. We obtain two-sided boundary conditions of impedance type that allow one to replace any flat grating of resistive strips with a plane of discontinuity of the electromagnetic field.