Analysis of a nonconfocal suspended strip in an elliptical cylindrical waveguide

The separation of variables method along with an addition theorem of Mathieu functions are employed in this paper to analyze the problem of a nonconfocal suspended strip in an elliptical waveguide. An infinite-dimensional determinant is obtained, which represents the characteristic equation of the proposed structure. To obtain the cutoff wavenumbers for both TE and TM cases of such a structure, the infinite determinant is truncated. Convergence when truncating was observed. Numerical results for the special case of a confocal structure is discussed first for comparison with published data. Results of other interesting cases are also presented