The use of higher order parabolic arcs for the computation of cutoff wavenumbers for TM modes in arbitrary shaped waveguides

This paper presents the use of Quartic and Quintic order finite elements for computing cutoff wavenumbers of arbitrary shaped waveguides. These finite elements are used for mapping the boundaries of waveguides with the highest accuracy. In the case of waveguides with curve geometries, the mapping is done by quartic and quintic order parabolic arcs. The domain of a particular waveguide is transformed to a suitable isosceles triangle with the help of these finite elements. The above method is found to be highly computationally efficient as compared to other methods found in literature.