ANALYSIS OF ELECTROMAGNETIC SCATTERING BY ARTIFICIALLY SOFT DISCS

An analysis of the electromagnetic behaviour of corrugated artificiall y soft discs, illuminated by a vertical dipole, was carried out by usi ng both numerical and asymptotic methods. The finite-difference time-d omain method was used to find near-field distributions. This allows th e consistency of the artificially soft model to be tested; furthermore , the near-field data are used to find the radiation pattern by using near-to-far-held transformations. The direct scattering in the far zon e was also obtained by using edge integration of incremental diffracti on coefficients; these are derived by applying the localisation proces s of the incremental theory of diffraction to a wedge with perfectly s oft boundary conditions on one face and perfectly electric boundary co nditions on the other. The effect of the corrugations is analysed in t he far-field limit by comparison with a perfectly conducting disc.