PROPAGATION PROPERTIES OF OVERMODED DIELECTRIC O-WAVEGUIDES——DIELECTRIC WAVEGUIDE THEORY

The normal modes in overmoded dielectric O-waveguides of arbitrary materials are analyzed in detail, particularly the variation of their propagation properties with material parameters, dimensions of the waveguides and frequencies. A simple and exact mode classification is presented. The separate characteristic equation of each type of normal modes is derived without solving directly the complicated characteristic equation.There are three types of normal modes: the surface mode, the interface mode and the leaky mode. Propagation properties of these three types of modes are discussed. The approximate solutions to their characteristic equations are given. The limit results of this paper are consistent with that given in literatures. The analysis shows that the propagation properties of the overmoded dielectric O-waveguides can be controlled by choosing proper materials and waveguide dimensions.