SCATTERING FROM METALLIC SURFACES HAVING A FINITE NUMBER OF RECTANGULAR GROOVES

A modal theory is presented for solving the problem of electromagnetic scattering from a surface consisting of a finite number of one-dimensional rectangular grooves in a metallic plane. The incident plane wave can be polarized with either its electric or its magnetic field along the grooves. The formalism is applicable to perfectly conducting materials and to real metals with high (but finite) conductivity. Particular attention is paid to the changes appearing in the scattering pattern when the conductivity of the structure is changed from an infinite value (perfect conductor) to a finite value (highly conducting metal). The excitation of surface waves when the incident wave is p polarized is illustrated in some numerical examples that demonstrate the differences between the spectral amplitudes corresponding to s and p polarizations.