Full-wave and Exact Analysis of Space-Wave in a Two-Layer Cylindrical Dielectric Rod

In this paper, a full-wave and rigorous formulation is presented for the analysis of the space-wave characteristics in a two-layer cylindrical dielectric rod. The closed-form expression of the radiated field for the space-wave due to the ž -directed electric source is derived. Contour-deformation of the Sommerfeld integral along the branch-cut to the steepest-descent path is used to evaluate the contribution of the space-wave. Parametric variation of the space-wave radiation pattern for all design parameters of the cylindrical rod structure are also investigated.