Coupling of Modes in Uniform, Composite Waveguides

The principle of coupling of modes is used to compute the phase constant in a uniform waveguide Iilled with two ditferent dielectric materials. The natural modes of two hypothetical waveguides filled with the different dielectrics are computed. The propagation of the combined system is computed by considering the coupling between the two sets of modes. Comparison is made between the approximate theory and an exact theory.