Radiation Properties of Arc Antennas in a Warm Plasma

Abstract

General expressions for the radiation properties of centre-fed standing wave circular arc antennas in a compressible electron plasma are derived in terms of the plasma and antenna parameters. The effects of these parameters on the antenna radiation characteristics are evaluated numerically and shown graphically for quarter-, semi- and three-quarter-circular arc and loop antennas. It is observed that the radiation properties depend ignificantly on the plasma frequency. For a given antenna size and plasma frequency, the power radiated in the electromagnetic mode decreases with increasing antenna curvature, while that radiated in the plasma mode remains almost independent of the antenna's shape. The radiation efficiency of an arc antenna thus decreases with increasing curvature.