High-Frequency Electromagnetic Field Coupling to a Long, Finite Wire With Vertical Risers Above Ground

The main goal of this paper is the analytic approximation of the singularity expansion method poles of a long finite wire with vertical risers above a perfectly conducting ground. For wavelengths in the same order of magnitude or smaller than the height of the wire above the ground, the classical transmission-line theory is not valid. Therefore, an asymptotic approach is used to approximate the current on the thin wire, which is expressed in terms of current reflection and scattering coefficients. The perturbation theory is used for their analytic calculation. The complex current is analytically approximated and compared to a numerical simulation for illustration purposes. A very good agreement between the analytic approximations and the numerical ones from literature and simulations is observed.