Long-wire Antennas

Author: Edmund A. Laport

The simplest high-gain antennas (structurally) are those using electrically long wires in various configurations. The length of the wires may be from one to eight wavelengths or more, and several of these wires may be used, according to the particular performance desired. Long wires may be excited so as to support standing waves or traveling waves. Practical circumstances of construction and feed, however, are of a compromising nature so that a standing-wave system always contains a substantial component of traveling wave, and vice versa.

It is one of the paradoxes of engineering in this field that the simplest antennas are the most difficult to analyze. Long-wire antennas, which permit the simplest structures for a given performance, involve an enormous amount of computation to determine their performance. Furthermore, an accurate analysis is virtually impossible because of the several empirical factors present.

In view of the importance of long-wire-antenna technology and the difficulties of precise analysis, it is necessary to examine in some detail the principles of long-wire systems of both standing-wave and traveling-wave types.