Element-free method for the analysis of arbitrarily-shaped hollow conducting waveguides

The element-free method, which originates from computational mechanics and has been applied in electrostatic problems, is modified and extended to the Helmholtz wave equation for the computation of the cut-off wavenumbers of arbitrarily-shaped hollow conducting waveguides. The method is validated by comparison with published results on L-shaped, single-ridged, double-ridged, and rectangular waveguides with rounded corners. It is found that the cut-off wavenumbers can be accurately determined by the element-free method.