Abstract: A dielectric inset mountable within a conical horn antenna for focusing an impinging electromagnetic wave front as a planar wave front at an attached wave guide. In one construction a homogeneous inset having an ellipsoidal forward surface and conical aft surface is fitted into a double flared conical antenna including a cylindrical, hybrid mode matching section. In various alternative compound constructions, materials of differing dielectric constants and geometrical shapes are arranged to facilitate a size and weight reduction of the inset and focus the incident wave front relative to the wave guide. In other embodiments, still lower density materials, including suspended metallic particulates are used.

Abstract: A small aperture horn antenna comprising an outer conical shell and interiorly of which are formed at least first and second conically flared, dielectric-coated stages of differing flare angles which are coupled to one another via an intermediate cylindrical stage. The dielectric coating is applied to form a uniformly smooth horn interior surface. Mountable to the antenna input aperture are various reflective and homogeneous dielectric refractive focusing lenses and to the output is a low noise waveguide converter. A remotely controlled, axial mount assembly enclosed in a gas-filled, roof mountable radome is also disclosed. Alternatively, the same antenna geometry may be used to transmit a directive electromagnetic wave.