The effect of rounding vertices on the diffraction from polygons and other scatterers

The changes induced in the near- and far-field scattering by rounding the corners of an illuminated obstacle are discussed as a function of the radius of curvature near such corners. Dirichlet, Neumann or impedance boundary conditions are imposed on the surface. An integral equation formulation is employed; it is found that a graded mesh is necessary to obtain accurate results as well as to enable efficient calculation.