On the choice of an auxiliary contour involved in the problem of diffraction by a periodically irregular surface solved with the help of the null-field method.

The 2D problem of diffraction of a plane wave by a periodically irregular perfectly conducting surface is solved with the help of the null-field method. Comparative analysis of the computation accuracy is performed for various techniques of choosing an auxiliary contour on which the null-field condition is imposed. It is shown that the choice of an auxiliary contour based on the analytical deformation of the surface contour is an optimal technique. [ABSTRACT FROM AUTHOR]