Analysis of dielectric-loaded waveguide

The calculation of eigenvalues including propagation constants and cutoff wavelengths of longitudinal section electric and magnetic modes of different orders (LSE_nm and LSM_nm modes) in homogeneous and inhomogeneous lossless dielectric-slab-loaded rectangular waveguides using a modified variation-iteration method is presented. The initial eigenvalues used in the iteration are selected on the basis of a physical consideration. As shown in numerical examples, this method is very efficient for finding all the eigenvalues of LSE_nm and LSM_nm modes by a given free-space propagation constant calculation and a given lower bound of the cutoff wavelength for the cutoff wavelength calculation. In addition, the importance of the adaptive update factor in preventing the possibility of missing existing eigenvalues is also discussed