CORRECTION TO THE ANALYSIS OF DIELECTRIC GUIDES BY TRANSVERSE MAGNETIC-FIELD FINITE-ELEMENT PENALTY-FUNCTION METHOD WITH EXTENSIONS

Recently a method to obtain the propagation constants of lossless diel ectric waveguides using the Helmholtz equation with the finite element method and penalty function method was presented [1], The advantage o f using this approach is that only one final eigenvalue matrix needs t o be solved for only two components of the H-fields, We have determine that the results in [1] were obtained using an eigenvalue solver that did not account for the asymmetry in the final eigenvalue matrix. In this paper, we present the results of the same cases simulated using t he correct eigenvalue solver, and the results obtained are in good agr eement with previously published ones [3] and [4], We also show by sim ulation of appropriate cases, a high penalty factor is correlated to h ighly coupled modes, while weakly coupled modes may be correlated to s mall penalty factors, Finally, we have extended the penalty function m ethod to include the complex case without the use of the perturbation method, The gain results obtained for a channel waveguide are in good agreement with previously published ones [7] and [8].