Dispersion of waves guided along a cylindrical substrate-superstrate layered medium

The effects of curvature and of the electrical parameters of thin dielectric layers deposited as superstrates on a perfectly conducting circular cylinder on the modal dispersion of waves guided tangentially along the outer (superstrate) layer of a two-layer geometry are examined. To chart the propagation characteristics of the layer-guided modes relevant to the three-dimensional (dipole-excited) Green´s function for this geometry, it is necessary to solve the radial eigenvalue problem for the complex azimuthal propagation constants ν _p(β), p 1, 2, . . ., which also identify poles of the ν-dependent spectral integrand of the Green´s function. Here, β is the spectral variable along the axial direction, with the Green´s function synthesized as a double spectral integral over ν and β. The pole locations are obtained numerically by solving the dispersion equation using Davidenko´s method, and are parameterized in terms of layer radius, dielectric constant, and thickness. The dispersion relation, and hence the propagation constants, are shown to reduce correctly to the corresponding results for the planar geometry in the limit where the superstrate outer radius approaches infinity