Geodesic cone antenna

The subject of this paper is a novel phased array antenna which is capable of providing 360 degree continuous scanning with low side lobes over a wide band. The antenna consists of a ring of feed elements coupling energy through a coaxial conical waveguide to a circular radiating aperture. Rays from the feed ring are constrained within the conical coaxial waveguide and propagate along geodesic paths in such a way as to be focused in the far field. A paper presenting a preliminary design of a Geodesic Lens Antenna was presented at this symposium in 1981. Since that time, evaluation has shown performance equivalent to a linear aperture illuminated with a Tchebyshev distribution. Progress achieved in computer aided design and analysis allows tailoring a Geodesic Cone Antenna to the specific needs and constraints of given applications. A brief explanation of the function of the Geodesic Cone Waveguide using geometric optics is presented. Design and analysis techniques utilizing geometric optics and modal analysis are described. A half octave demonstration model of a Geodesic cone Antenna has been built and tested and showed good correspondence with predicted performance.