Analytical evaluation of Sommerfeld integral tails for layered-media Green´s functions

Green´s functions for layered media find applications in analysis of radar cross sections, radiation problems for array sources embedded within complex materials, prediction of electric fields from lightning, remote sensing, shipborne EMI/EMC issues and other various applications. Central to the predictions, for such applications, is the need for accurate evaluation of the appropriate Green´s functions that contain Sommerfeld integrals. In this paper a method is proposed for direct, real-axis integration of Sommerfeld integrals, obviating the calculation of pole locations and their residue contributions, with the integral tail evaluated analytically in closed form. The computational efficiency of the proposed algorithm is illustrated here with preliminary results by analyzing the G_zx component of the Green´s function for a HED inside a PEC-backed, double-layer dielectric media. Finally, the present method appears to be better amongst other similar approaches because it can better model the inhomogeneity of the constitutive electrical parameters in the vertical direction of the PEC-backed layered structure.