A T-matrix approach for EM scattering by a perfectly conducting periodic surface

The novel use of a Fourier exponential representation of the field induced on a perfectly conducting periodic surface is shown to yield a T-matrix which is numerically stable for deeply corrugated surfaces. Whereas the Rayleigh hypothesis limited the maximum slope of the surface to less than 0.448 in Waterman's original T-matrix scheme [1], our T-matrix is applicable even when the maximum slopes are of the order of 1.5.