An improved formulation of an optimizing Rayleigh-Ritz technique for closed dielectric waveguide analysis

It is shown that use of the E_Z/H_Z formulation to describe the modes of the homogeneous rectangular waveguide leads to a relative convergence phenomenon as well as to incorrect loss calculations. The method is reformulated using an E_x/E_y /H_x/H_y description of the homogeneous modes. The formulation is validated for step-index waveguides through nonperturbational calculations of the propagation and attenuation constants of the round step-index dielectric waveguide. Comparison with the direct eigenvalue solution shows excellent agreement for the dominant and three higher-order modes. The formulation is validated for graded-index waveguides through calculation of the dispersion curves for three modes of a Gaussian-Gaussian graded-index channel waveguide. Comparison of the results with those of two other methods shows excellent agreement