Diffraction problem by a system of rectangular slots in a common wall of rectangular waveguides

The diffraction problem by a system of rectangular slots in a common wall of two rectangular waveguides is considered. At first, using the mode-matching technique and the singular integral equations approach the diffraction problem by the gap of two semiinfinite regular rectangular waveguides and two semiinfinite rectangular waveguides with semiinfinite slots in a common wall is solved. Then, the solution of diffraction problem by one cell, containing slots, and by bounded system of cells is obtained using the operator approach.