Perfectly conducting gratings: a new approach using infinitely thin strips

A new approach is proposed to resolve the diffraction by a perfectly conducting grating with arbitrary shape and depth illuminated under TE polarization. It approximates the grating by a set of infinitely thin, perfectly conducting strips, parallel to the mean plane of the grating, whose widths follow the groove shape. When the distances of the neighbouring strips are thin enough, the set of strips separated by a dielectric turns out to be equivalent to a bulk metal and produces the same diffracted field. Comparisons are made with previously developed methods and the advantages of the new one are pointed out. (C) 1997 Elsevier Science B.V.