Radiation characteristics of selected long wire antennas as a function of geometry using computer modeling techniques

Abstract

This thesis, sponsored by the Marine Corps Development and Education Command, Quantico, VA, examines the far field patterns of five high frequency long wire antenna configurations through the use of the Numerical Electromagnetics Code (NEC). Lossy ground and the effects of variations made to these structures are considered. The resulting far field patterns are contained in the appendix. The antenna configurations vary in length from l.87 to 17.19 wavelengths and in their height above ground from 0.103 to 0.610 wavelengths. Variations in the antennas end-regions include: the use of a ground rod or radial screen attached to the transmitter, terminating the far end of the antenna, and varying the shape of the transmitter from a small box (radio-sized) to a large (vehicle-sized) configuration. It is concluded that both the antenna height and length determine the far field geometry, and that end-region variations also impact, though to a lesser degree, on the pattern. Tables of comparative results are provided.