Recent annular slot array experiments

The following paper describes a series of annular slot antennas capable of producing omnidirectional beams, linearly and circularly polarized pencil beams, and a search type fan beam. Modifications of certain physical and electrical characteristics of annular slots have made construction simple and eliminated some of the undesirable radiation pattern characteristics of basic annular slots. These antennas may be made lightweight and occupy little volume. Most of the antennas developed are narrow band devices. Feeding methods would have to be altered where band width is imperative. This work was executed at 9000 mc.