Numerical modeling of monopoles on radial-wire ground screens

The monopole antenna on a radial-wire ground screen has been particularly resistant to numerical modeling due to the difficulty of treating the effect of the air-ground interface and the large total electrical length of wire involved. A moment-method code capable of modeling ground screens and other antennas near to or buried in the ground was developed in the code NEC-3 (numerical electromagnetics code-3). A version of NEC-3 known as NEC-GS was then specialized to model vertical monopoles or uniform radial-wire ground screens, taking maximum advantage of the symmetry of the screens and their currents. Some results of this code are presented to compare the performance of ground screens of varying dimensions and configurations, and to determine optimum design parameters.<>