Finite element analysis of dispersion in waveguides with sharp metal edges

The dispersion characteristics of arbitrarily-shaped waveguides with sharp metal edges are found by a finite-element method in which the usual polynomials are supplemented by singular trial functions. The method solves for the three components of magnetic field and can thereby avoid spurious modes. Results of the method are provided for shielded microstrip on various substrates and a rectangular waveguide example.<>