A Complete Uniform Asymptotic Expansion of Dyadic Green’s Function for Dielectric Half-Space Including Plasmonic Media

As usual, the first- or second-order asymptotic expansion (AE) of the Sommerfeld integral (SI) for the dielectric half-space has been formulated and used, which may limit its valid region. Recently, the complete nonuniform and uniform AEs of the dyadic Green’s function (DGF) have been formulated, for the dielectric half-space and the impedance plane, respectively. Thus, by combining these two expansions, a complete uniform AE can be formulated for the dielectric half-space, which can then be slightly modified to include the exact residue contribution. The formulated complete uniform AE is numerically compared with the results of the numerical integration and the conventional first- or second-order uniform expansions for ordinary and plasmonic half-space and various antenna configurations.