Nodal and edge element analysis of inhomogeneously loaded waveguides

Comparisons of nodal and edge finite element analyses of inhomogeneously loaded waveguides are made. For nodal elements, the vector potential together with a scalar potential description is applied. For edge elements, the field description is used. Both descriptions are free of spurious solutions. The case of the treatment of the propagation constant as an eigenvalue is also discussed. A modified version of the bisection method is used when the matrices of the eigenvalue problem are not positive definite. Examples including waveguides with sharp metal edges are presented to compare the different methods. For problems with sharp edges, the edge element approximation is favorable