Rigorous analysis of arbitrarily shaped H- and E-plane discontinuities in rectangular waveguides by a full-wave boundary contour mode-matching method

A rigorous boundary contour mode-matching (BCMM) method is presented for the efficient calculation of the modal scattering matrix of arbitrarily shaped Hand E-plane discontinuities, junctions, and/or obstacles in rectangular waveguides. For the inhomogeneous waveguide region with general contour, the field is expanded in the complete set of cylindrical wave functions. The full-wave expansion allows the immediate rigorous inclusion of cascaded structures such as combined H- and E-plane bends. The efficiency of the method is demonstrated at the rigorous design of useful waveguide components which could not be modeled by mode-matching technique so far: cylindrical post-compensated H-plane T-junction, mitered H-plane and E-plane bends of arbitrary angle, cascaded H-/E-plane bends, circular post-coupled filter, E-plane filter with rounded corners, 180° rat race structure, and side-coupled dual TE₃₁₁/TE₁₁₃-mode filter. The theory is verified by measurements