Patent ID: 7068233
Filing Date: 2006-06-27
Classification: H01Q

Abstract:
1. An integrated dual antenna system having broadband elements and nearly constant group delay that provides complete upper hemispherical coverage, comprising (a) an MLA antenna having both active and RE choke large diameter cylindrical dipole elements and coaxial feed lines each of which is connected to an active cylindrical dipole element, each of said feed lines having line lengths which vary in length plus or minus only the length required to achieve a desired phase variation across the antenna aperture; and (b) an HZA antenna having a broad-band cross-V-dipole, so that together the HZA and MLA antennas provide a large bandwidth with radiation characteristics that are not sensitive as a function of relative element geometries between the HZA and MLA antennas, and wherein said system implemer is a multiplicity of techniques to achieve high D/U ratio, S/N ratio, low sidelob: levels and gain flatness, minimum phase and group delay in its coverage area which has in combination: a) a flat, conductive, counterpoise oriented orthogonal to the vertical axis of the antenna system; b) a shaped concave reflector and associated counterpoise electrically connected to a second conductive counterpoise which electrically and mechanically connects the cross-V-dipole to a beam forming network; c) a vertically oriented, quarter wave, RF choke which suppresses the surface wave traveling along the surface of a microwave absorbing material; d) a precisely shaped piece of RF absorbing material with specific carbon fill factor having a shaped inside surface to control a positive angle radiation pattern and whose shaped outside surface helps control the broadside and negative angle portions of the radiation pattern; e) a highly symmetric cross-V-dipole having RHCP output polarization which produces a symmetry and ellipticity ratio over the service volume; and f) a specifically defined geometry between each mutually interactive element of the HZA antenna.