Radiation Characteristics of Bent-Wire Antennas

A mathematical model, which predicts the far-field power pattern of a wire antenna bent in one plane, is developed, and the classical approximation of a sinusoidal current distribution along the arc length is employed, neglecting all end and mutual coupling effects. General expressions for the complex Poynting vector, electric- and magnetic-field intensities are also derived in terms of the retarded vector potential. Although the theory for parabolically-bent antennas compares favorably with experiment, it is shown that the agreement is more favorable when the current distribution is computed by the method of moments. In contrast to the figure-eight ¿-plane pattern of the conventional straight dipole, the circularly and parabolically bent antennas operating at the first resonance are shown to have radiation patterns approaching omnidirection as the bending curvature is optimized, thus lending themselves to use as replacements for many common dipole applications for gain standards, field probing, reflector feeds, as well as mobile and broadcast antennas.