ELECTROMAGNETIC SCATTERING THEORY FOR GRATINGS BASED ON THE WIENER-HOPF-FOCK METHOD

The diffraction problem of a plane electromagnetic wave incident on an ideally conducting grating is solved with the Wiener-Hopf-Fock method. In contrast to the standard Wiener-Hopf method having a single integral equation, the boundary value problem is reduced to a system of integral equations. The short wave asymptotic solution of this system is obtained by means of the saddle point method and expressed in terms of the etalon integral. It contains a resonant denominator which determines the eigenfrequencies of the grating. A precision not below the inclusion of tertiary diffractions is provided by using the saddle point method and the etalon integral for the main contribution of the integrals in the solution. The given method has a clear advantage when the grating consists of a finite number of strips.