Resistive receiving and scattering antenna

Abstract

This work is a sequel to two earlier papers devoted to detailed theoretical and numerical analyses of the imperfectly conducting cylindrical transmitting antenna [1], [2]. A knowledge of the driving-point impedance of the transmitting antenna, as previously reported, and the short-circuit current, as derived in this paper, completely determine the receiving properties of the resistive antenna. It is assumed that an internal impedance per unit length may be defined for the resistive cylinder. This study was prompted primarily by the desire to determine the current distribution along an ionized column of gases when the dielectric constant and conductivity are known, and also along imperfectly conducting missiles in free flight following burnout. The radar cross section of a gas column is readily obtained from the induced current distribution. Current distributions along several representative resistive cylinders as well as scattering cross sections are computed considering broadside illumination by a plane-wave field. The analysis yields accurate results whenk_{0}a \ll 1, h \gg a, andk_{0} h \leq 5\pi /4. Herek_{0}is the free-space wave number;handaare the antenna half length and radius, respectively.