Solution of wave diffraction problems by the null-field method

Numerical realization of the null-field method for solving wave diffraction problems is investigated. It is shown that this method provides correct and stable algorithms only when the null-field surface encloses the set of singularities of the analytic continuation of the wave field inside the scatterer. Considering specific examples of diffraction problems, it is demonstrated that the null-field surface is best constructed by analytic deformation of the scatterer’s boundary.