Exact image method for impedance computation of antennas above the ground
Abstract
A principle of exact image developed for the Sommerfeld problem is applied to the classical impedance problem of antennas above the ground. The effect of the ground is taken into account with an image source located in complex space, leading to a modified Green function for the antenna current integral equation. The image of the antenna can be determined through expressions evaluated for the image current function. The stationary functional for the antenna impedance is extended to take into account the effect of the ground. Impedance expressions for small dipoles and halfwave dipoles are calculated and compared with previous results. Methods for calculating the impedance of wire antennas with finite thickness from that of infinitesimally thin antennas, and to determine ground parameters from horizontal dipole minimum resistance and height measurements are presented.
 Publication:

NASA STI/Recon Technical Report N
 Pub Date:
 1984
 Bibcode:
 1984STIN...8615535L
 Keywords:

 Antenna Radiation Patterns;
 Imaging Techniques;
 Impedance Measurement;
 Sommerfeld Waves;
 Dielectric Properties;
 Field Theory (Physics);
 Green'S Functions;
 Parameter Identification;
 Communications and Radar