Trw Limited

Hughes Aircraft Company

Northrop Grumman Systems Corporation

The United States of America As Represented by the Administrator of the

E-systems, Inc.

Te-Kao Wu

Brent T Toland

Charles W Chandler

David L Brundrett

Andrew Lee Roberts

William W Milroy

Chun-Hong Harry Chen

Kenneth C Kelly

Steven Szu-Cherng Kuo

Mark E Bever

Darrell L Helms

George H Simkins

Steven W Drost

John J Macek

Benny Yee

Teh-Kan Tung

George M Haney

Romulo F J Broas

Kenneth A Hummer

Sundeep Puri

Systems are disclosed for providing substantially equal E-plane and H-plane radiation patterns in a high power and dual band coaxial feedhorn antenna for a satellite communication system. One embodiment may include a coaxial feedhorn antenna comprising an outer coaxial horn portion for propagation of first signals and an inner horn portion for propagation of second signals. The coaxial feedhorn antenna may also comprise a conductive choke-ring coupled to the outer conductive wall, the conductive choke-ring being coaxial with the outer coaxial horn portion and the inner horn portion. The conductive choke-ring provides substantially equal E-plane and H-plane radiation patterns of the first signals and substantially reduced back-lobes.

High-power dual-frequency coaxial feedhorn antenna

A high power dual band high gain antenna system is provided. The antenna system employs one or more feedhorn clusters to distribute power associated with the transmission of high power signals. A first feedhorn cluster is associated with a first frequency band and a second feedhorn cluster is associated with a second frequency band that operates in frequencies below the first frequency band. The antenna system includes a sub-reflector and a main reflector with a first focal point of the sub-reflector being substantially aligned with a focal point of the main reflector. The first feedhorn cluster and the second feedhorn cluster are arranged on a surface of the main reflector with radiating aperture phase centers substantially aligned with a second focal point of the sub-reflector.

High power dual band high gain antenna system and method of making the same

A high performance multi-band antenna reflector having low sidelobe and cross polarization levels, and a superior carrier-to-interference ratio has two concentric zones ( in a first embodiment and in a second embodiment). In the first embodiment, the outer concentric zone ( ) is a frequency selective absorber ( ) made of a metallic pattern ( ) dimensioned to reflect signals in one frequency band and absorb signals in a second frequency band. In the second embodiment, the outer concentric zone ( ) is a frequency selective surface ( ) that reflects signals in one frequency band and passes signals in a second frequency bands. Resistance cards ( ) overlay the top and bottom sides of the junction between the frequency selective surface ( ) and a reflective layer ( ) on an inner surface ( ) of the central concentric zone ( ).

High performance multi-band frequency selective reflector with equal beam coverage

An antenna feed in a satellite system that provides substantially equal E-plane and H-plane patterns. The feed includes outer and inner conductive walls that are coaxial, and define an outer waveguide therebetween and an inner waveguide within the inner conductive wall. The feed includes a first cylindrical waveguide section, a tapered waveguide section, and a second cylindrical waveguide section at the aperture of the feed. Downlink signals are in signal communication with the first cylindrical waveguide section so that the downlink signals are launched into the outer waveguide and out of the feed. Uplink signals received by the inner waveguide are directed to suitable uplink reception devices. One or both of the outer or inner conductive walls include an array of radially disposed iris pins at the aperture that interact with the uplink and/or downlink signals to provide beam symmetry or equal E-plane and H-plane patterns.

Dual frequency coaxial feed with suppressed sidelobes and equal beamwidths

Compact frequency selective reflective antenna

An antenna system comprising a feed array, a subreflector and a main reflector which are oriented to define a folded optics antenna geometry. The feed array is comprised of a plurality of separate feeds which are aligned on a predetermined contour. Each feed is coupled to a feed network which acts to combine the illumination beams of a preselected number of feeds to produce a plurality of composite illumination beams. Each composite illumination beam is directed to be incident upon a separate predetermined location on the subreflector which directs the illumination beams towards the main reflector. Each composite illumination beam is reflected by the main reflector in a preselected direction so that each composite illumination beam forms an antenna beam that impinges a predetermined coverage area on the Earth. Each antenna beam defines a separate coverage cell in the coverage area, wherein the position and orientation of the feeds, the subreflector and the main reflector provides adjacent, antenna beams over a full Earth field of view coverage area where each antenna beam is approximately symmetrically shaped.

Compact folded optics antenna system for providing adjacent, high gain antenna beams

Wideband matching surface for dielectric lens and/or radomes and/or absorbers

A phased antenna array ( ) for use on a satellite, that employs a density tapering technique for positioning the antenna elements ( ) in the array ( ) to reduce co-channel interference between adjacent cells. Particularly, the spatial position of the various antenna elements ( ) in the array ( ) are spread out so that the center portion of the array ( ) has the highest density of elements ( ), and the outer portion of the array ( ) has the lowest density of elements ( ). Predetermined schemes are used to set the density of the elements ( ) in the array ( ). By providing fewer antenna elements ( ) at the outer portion of the array ( ), the beam side lobes are reduced.

Density tapered transmit phased array

A multi-layer grid ( ) for an antenna system ( ). The multi-layer grid includes a first panel ( ) and a second panel ( ). Each panel is formed utilizing a pair of outer layers ( ) which are adhered to a dielectric foam ( ). A low loss adhesive layer ( ) enables bonding of dielectric foam ( ) to each of respective outer layers ( ). A spacer ( ) provides a predetermined spacing between first panel ( ) and second panel ( ). A frequency selective surface filter ( ) is disposed on the outer layer ( ) of each panel ( ).

Precision multi-layer grids fabrication technique

A multi-pattern antenna for providing a plurality of antenna patterns at different frequencies or polarizations from a single reflector body eliminates the need for multiple reflector antennas on a single spacecraft. The reflector antenna comprises a reflector body and an illumination source. The illumination source illuminates the reflector with a plurality of RF signals each of a preselected frequency or polarization. The reflector comprises a plurality of zones with each zone reflecting preselected RF signals. A plurality of antenna patterns are generated from the reflected RF signals. Each zone is sized to a preselected shape such that the antenna patterns have a desired shape or beamwidth characteristic.

Multi-pattern antenna having frequency selective or polarization sensitive zones

A frequency selective medium that is adapted to receive an incident electromagnetic radiation at an angle of incidence of about 45.degree. has two arrays of conductive elements on opposite parallel surfaces (20, 22) of a dielectric substrate. In one embodiment, the conductive elements are cross-dipoles (6) each having a horizontal dipole (10) and a vertical dipole (8) of different lengths and widths. In another embodiment, the conductive elements comprise a plurality of conductive gridded rectangular loops (40). The frequency selective medium allows incident waves that are within a passband of transmit frequencies to transmit through the medium, and reflects waves at frequencies within a stopband adjacent the passband. In other embodiments, meanderline polarizers (28) are added to cross-dipole and gridded rectangular loop frequency selective media to circularly or dual-linearly polarize incident linearly polarized waves.

Dual polarization frequency selective medium for diplexing two close

A frequency selective surface filter (20 or 50) particularly useful in connection with a transmit antenna (10) for passing and rejecting signals in multiple frequency bands. According to one embodiment, the frequency selective surface filter (20) has a single conductive screen (24) disposed on a dielectric medium (22). The single-conductive screen (24) includes an array of parallel intersecting lines (26) and (28) providing low frequency filtering. The single-conductive screen (24) also includes an array of double-loop conductive elements each made up of an inner conductive loop (32) and an outer conductive loop (30). According to a second embodiment, the frequency selective surface filter (50) contains two dielectrically separated conductive layers including a first conductive layer (52) having an array of double-slots made up of an inner slot (64) and an outer slot (66). The double-slot configuration further includes a second conductive layer (60) made up of an array of single conductive loops (62).

Frequency selective surface (FSS) filter for an antenna

The problem of reducing the size of a dual offset Cassegrain reflector type microwave antenna without adversely affecting performance while retaining the simplicity of the main reflector's (1) and subreflector's (3) traditional simple surface curvatures is solved by having the paraboloidal shaped main reflector's focal length, fm, and diameter, D, fulfil the criteria that the ratio of fm to D is less than 1.0; and in which the hyperboloidal shaped subreflector (3) is oriented so that its left foci, at which the microwave feed (5) aperture is placed, lies above the main reflector's focal axis. It's subreflector subtends an angular arc about the focal point that is slightly larger than the corresponding arc subtended by the main reflector. The elegance of the compact antenna is demonstrated by improved performance, attaining efficiencies in excess of seventy three percent.

Growing community of inventors

Rancho Palos Verdes, CA, United States of America

Te-Kao Wu