Abstract: A broadband spiral antenna including a tubular member having a planar surface at one end, a planar spiral element supported on the planar surface and radiating outward from a central position on the planar surface to an edge position on the planar surface, and an array of dipole elements supported on and extending around the tubular member and coupled to the planar spiral at the edge position.

Abstract: A coplanar stripline antenna including a layer of dielectric material supporting a lower ground plane of conductive material on one side of the layer of dielectric material, a patch of conductive material on the other side of the layer of dielectric material, and an upper ground plane of conductive material on the other side of the layer of dielectric material and with the upper ground plane substantially surrounding and spaced from the patch of conductive material.Electrical signals are fed to the antenna between the patch of conductive material and the upper ground plane. A number of patches of conductive material may each be surrounded by the upper ground plane to form an antenna array and with the patches interconnected by coplanar stripline fed at a point equidistant from each patch.

Abstract: A circularly polarized, broad-beamed antenna system capable of effectively covering the entire bandwidth of from about 0.5 GHz to about 18 GHz or higher. The system provided comprises a generally conventional planar spiral antenna modified by having the outer ends of its arms terminated by a bifilar helix. The bifilar helix is positioned behind the planar spiral and at 90.degree. to it. By proper coupling of the two antenna portions, it has been found that within the 2 to 18 GHz range, the planar spiral operates as if the helix were not present, while below 2 GHz, the spiral functions as a transmission line feeding the helix and the helix radiates essentially all of the energy from the antenna.The antenna system provided is approximately the same size as conventional 2 to 18 GHz cavity backed spiral antennas and generally satisfies all of the physical constraints and limitations placed upon airborne radar-warning systems.