Reflector-type periodic broadband antennas

Abstract

Operation of a logarithmically periodic radiating element over a reflecting cavity is described, and the limitations on frequency bandwidth are discussed. Methods of overcoming these limitations are presented.The most promising method involves the use of dielectric materials in the cavity.Data are presented on two operating models: one, designed for minimum size, covering a 3 -to-1 frequency band with a maximum VSWR of 3 to 1, and the other, somewhat larger, covering a 4.5-to-1 band with a peak VSWR of 5 to 1. Both antennas exhibit essentially constant pattem characteristics over these bands.cone feed, the helix, the spiral, ridged waveguide horns, end fire arrays, etc. Figure 1 is a photograph of this antenna, model "A" at left and Model ''El1 at right.