SURFACE FIELDS AND RADIATION PATTERNS OF A VERTICAL ELECTRIC DIPOLE OVER A RADIAL-WIRE GROUND SYSTEM

Abstract

SUMMARY EM propagation over and radiation from radially varying ground systems are numerically modeled using the compensation theorem integral formulation. The source is taken to be a vertical electric dipole (VED) situated either on or above an azimuthally symmetric plane ground system having an assumed surface impedance profile which can vary arbitrarily in the radial direction. Because the formulation is based on the surface impedance concept, it can be applied to a variety of ground system configurations having a radius greater then about one wavelength. Particular attention is given to conventional HF radial-wire systems laid on both well and poorly conducting earth. For simple radial-wire ground systems, the radiation patterns were found to be independent of increasing radial length if the magnitude of the composite surface impedance is within 90percnt of the surface impedance of the underlying ground. It is also found that the radially varying feature tends to suppress high-angle lobes which are ot...