MONTE-CARLO SIMULATIONS OF LARGE-SCALE PROBLEMS OF RANDOM ROUGH-SURFACE SCATTERING AND APPLICATIONS TO GRAZING-INCIDENCE WITH THE BMIA CANONICAL GRID METHOD/

Scattering of a TE incident wave from a perfectly conducting one-dimen sional random rough surface is studied with the banded matrix iterativ e approach/canonical grid (BMIA/CAG) method, The BMIA/CAG is an improv ement over the previous BMIA. The key idea of BMIA/CAG is that outside the near-held interaction, the rest of the interactions can be transl ated to a canonical grid by Taylor series expansion, The use of a flat surface as a canonical grid for a rough surface facilitates the use o f the fast Fourier transform for nonnear field interaction, The method can be used for Monte-Carlo simulations of random rough surface probl ems with a large surface length including all the coherent wave intera ctions within the entire surface, We illustrate results up to a surfac e length of 2500 wavelengths with 25 000 surface unknowns. The method is also applied to study scattering from random rough surfaces at near -grazing incidence, The numerical examples illustrate the importance o f using a large surface length for some backscattering problems.