Abstract: A hybrid reflector antenna particularly suited for reflecting a frequency band in a satellite includes a central portion fully reflective to the frequency band. A first annular band is disposed directly adjacent to the central portion. The first annular band is partially reflective to the frequency band. The reflector may include several annular bands having various degrees of reflectivity and thus attenuation. The present invention may be implemented using two such reflectors, one for transmitting and one for receiving in a satellite, for either single or multiple beam applications. This invention offers more compact and lower mass/cost antenna configurations compared to conventional antennas from multiple beam satellite payloads.

Abstract: A hybrid reflector antenna particularly suited for reflecting a frequency band in a satellite includes a central portion fully reflective to the frequency band. A first annular band is disposed directly adjacent to the central portion. The first annular band is partially reflective to the frequency band. The reflector may include several annular bands having various degrees of reflectivity and thus attenuation. The present invention may be implemented using two such reflectors, one for transmitting and one for receiving in a satellite, for either single or multiple beam applications. This invention offers more compact and lower mass/cost antenna configurations compared to conventional antennas from multiple beam satellite payloads.

Abstract: An antenna system and method for generating a desired contiguous spot beam pattern, and a signal is disclosed. The contiguous spot beam generating antenna system comprises a reflector system configured in a side-fed Cassegrain (SFOC) configuration, an array of feed horns comprising at least a subset of feed horns for illuminating the reflector system, and a beamforming network, communicatively coupled to the array of feed horns, for controlling an excitation of the subset of the feed horns in the array of feed horns. The method comprises illuminating a side fed offset Cassegrain reflector system with an RF signal emanating from an array of feed horns, and controlling an excitation of the subset of the feed horns.

Abstract: A method and apparatus for producing contiguous spot beam communications coverage on the Earth's surface are disclosed. The apparatus comprises an antenna system including two wide scan antennas and two narrow scan antennas. The two wide scan antennas are disposed substantially opposite each other, and the two narrow scan antennas are disposed substantially opposite each other and substantially normal to the wide scan antennas. The first wide scan antenna, second wide scan antenna, and first narrow scan antenna produce a first beam pattern on a planetary surface and the first wide scan antenna, second wide scan antenna, and second narrow scan antenna produce a second beam pattern on the planetary surface.

Abstract: An antenna configuration suitable for LEO/MEO satellites includes a plurality of lenses whereby each lens has a plurality of feed horns positioned with respect to the lens. The lens has a first surface and a second surface. The plurality of feed horns is disposed upon a curved surface. Each of the plurality of feed horns generates a beam that has a phase distribution. The phase distributions have a predetermined phase relationship with the first surface and preferably the second surface. This allows the lens to transmit and receive a signal with desired phase distribution across a cross-section of the beam. The beams from the plurality of lenses are inter-leaved on the ground to form a contiguous coverage with multiple overlapping spot-beams.

Abstract: An antenna configuration suitable for LEO/MEO satellites includes a plurality of lenses whereby each lens has a plurality of feed horns positioned with respect to the lens. The lens has a first surface and a second surface. The plurality of feed horns is disposed upon a curved surface. Each of the plurality of feed horns generates a beam that has a phase distribution. The phase distributions have a predetermined phase relationship with the first surface and preferably the second surface. This allows the lens to transmit and receive a signal with desired phase distribution across a cross-section of the beam. The beams from the plurality of lenses are inter-leaved on the ground to form a contiguous coverage with multiple overlapping spot-beams.

Abstract: A unique feed structure for improving the cross-polarization performance of a reflector antenna system is disclosed. According to the present invention, the feed structure is an array including a number of feeds, which are rotated in a predetermined fashion to yield superior cross polarization performance of the antenna system. The array feed in the center of the feed structure is positioned approximately in the focus of the antenna reflector. The array feeds located on the y-axis are slightly rotated in either a clockwise or a counter-clockwise manner. The magnitude of the rotation is proportional to the distance of the feeds from the x-axis along the y-axis. The rotation of the feeds yields significant performance in cross polarization performance, while having little or no co-polarization effect.

Abstract: An improved dual gridded reflector antenna configuration which allows cross-polarization radiation to be scanned in any given direction. The dual-gridded reflector assembly includes a front parabolic reflector illuminated by a first source, and a second parabolic reflector illuminated by a second source. The second reflector is positioned adjacent to and behind the front reflector such that the center points of the reflectors align to define a center axis. Additionally, the first and second sources are positioned at different offsets with respect to the reflectors and have a respective rotated offset angle with respect to the center axis such that the sources define an antenna feed separation. By modifying the offsets and the rotated offset angles, the feed separation can be designed to have an inclination with respect to the north-south or east-west feed separation direction.

Abstract: A reconfigurable multiple beam phased array antenna has radiating elements arranged in a planar array and variable phase shifters. Each one of the phase shifters is connected to a respective one of the radiating elements. The array antenna further includes a beam forming network for forming spot and regional beam signals. The beam forming network forms a regional beam signal from a combination of spot beam signals. The beam forming network has two dimensional stacks of Rotman lenses provided with a first set of ports. Each one of the first set of ports is connected to a respective one of the radiating elements with. The Rotman lenses generate frequency invariant spot beam signals which are communicated between the radiating elements and the Rotman lenses via the first set of ports for transmission and reception of spot beams and regional beams by the radiating elements. The phase shifters are adjusted to steer the spot and regional beams to desired locations.