The method of moments in a problem concerned with the diffraction in the case of a planar waveguide with a flange

The diffraction of a TEM wave at the open end of a planar waveguide with a flange is considered, taking into account the mathematical description of the involved field and a system of equations obtained on the basis of the boundary conditions. An exact solution is obtained in the form of an infinite system of linear algebraic equations. The system of equations is transformed on the basis of a partial inversion of the operator. In the solution of the problem, use is made of the method of moments. The numerical results presented show that the use of the reduction method leads to a rapid convergence. The possibilities provided by the described method are analyzed by studying the solution of the diffraction problem in the case of a plane wave incident on a grating of metallic rectangular beams.