Dielectric Omni-Directional Antennas.

A circular symmetrical dielectric antenna structure and feed arrangement provide an omni-directional radiation pattern. The antenna includes a linear dielectric feed section, an integral radiating section having a taper which decreases outwardly, and an excitation means coupling millimeter wave energy to the feed section. The entire structure is circularly symmetrical about a central longitudinal axis. A first embodiment is in the form of a longitudinal dielectric rod having a uniform diameter at the feed end with circular periodically spaced corrugations at the radiating end. A tapered intermediate section has grooves of increasing depth, with the depth being constant at the remainder of the radiating end. A circular waveguide couples energy to a tapered dielectric transition section to provide excitation to the uniform feed end. A second embodiment is in the form of a flat circular disk having tapered radiating ends. A central metal cap limits radiation from the top surface.