Abstract: Resonant frequency stability of passbands or stopbands is provided over varying incidence angles and polarizations in a dual band frequency selective surface (FSS) device. The FSS device comprises an array of fractal unit cells. The fractal elements may comprise single fractal, or double fractal, or convoluted, or split ring resonator slot elements printed on a thin dielectric substrate. Each cell includes a first fractal pattern and a second fractal pattern which interact to provide the improved performance. In one form, a two-screen fractal FSS is etched on both sides of a thin dielectric substrate. The top FSS screen's unit cell has one fractal loop patch element, while the bottom FSS screen's unit cell has a higher order iteration of the same fractal. In another form, two fractal screens are incorporated in one dielectric layer positioned between two substrate layers. In yet another form, two fractal loop slot element FSSs are provided.

Abstract: 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.

Abstract: 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.

Abstract: A rectangular-to-circular mode combiner/divider is provided. In one aspect of the invention, a power combiner is provided that comprises a plurality of rectangular waveguide ports arranged in an integral arrangement. Each rectangular waveguide port is operative to operate in a rectangular mode. The power combiner is also includes a circular waveguide port operative to operate in a circular mode, and a transition body that couples the plurality of rectangular waveguide ports to the circular waveguide port. The transition body has an inner transition cavity and an outer body operative to convert radio frequency (RF) signals between the rectangular mode and the circular mode, and provide a combined output signal at the circular waveguide port from RF signals received at the plurality rectangular waveguide ports.

Abstract: 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.

Abstract: 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.

Abstract: A phased array antenna structure capable of operation at millimeter-wave frequencies and having multiple ring slot radiator elements (10). The RF feed structure for each radiator element includes a feed via (28) extending part-way through a multi-layer structure (FIG. 3) on which the radiator elements (10) are formed and a strip line feed probe (30) extending from the via (28) toward the radiator element. A key feature facilitating high-frequency operation is the inclusion of multiple mode suppressors (32) surrounding the via (28) and providing a smooth transition from a coaxial mode of RF transmission to a strip line mode of RF transmission. The feed probe (30) is tailored to provide either a narrow-band or a wideband frequency characteristic.

Abstract: A method for forming patterned metal layers to a higher degree of precision than if chemical etching were used. A thin metal layer carried on a thicker metal carrier layer is patterned by laser ablation. Then the thin metal layer, and with it the carrier layer, is laminated to a dielectric layer. Finally the carrier layer is removed, leaving the patterned thin metal layer bonded to the dielectric layer.

Abstract: A multi-mode, multi-choke feed horn that employs a plurality of chokes designed to excite the proper mode content in a satellite uplink signal or downlink signal over a particular wide bandwidth. In one embodiment, the feed horn includes five chokes, where the choke closest to the feed end of the horn has a depth of about 0.075″.

Abstract: 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 (12, 14 in a first embodiment and 102, 104 in a second embodiment). In the first embodiment, the outer concentric zone (14) is a frequency selective absorber (20) made of a metallic pattern (22) dimensioned to reflect signals in one frequency band and absorb signals in a second frequency band. In the second embodiment, the outer concentric zone (104) is a frequency selective surface (106) that reflects signals in one frequency band and passes signals in a second frequency bands. Resistance cards (122) overlay the top and bottom sides of the junction between the frequency selective surface (106) and a reflective layer (110) on an inner surface (112) of the central concentric zone (102).

Abstract: 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 (12, 14 in a first embodiment and 102, 104 in a second embodiment). In the first embodiment, the outer concentric zone (14) is a frequency selective absorber (20) made of a metallic pattern (22) dimensioned to reflect signals in one frequency band and absorb signals in a second frequency band. In the second embodiment, the outer concentric zone (104) is a frequency selective surface (106) that reflects signals in one frequency band and passes signals in a second frequency bands. Resistance cards (122) overlay the top and bottom sides of the junction between the frequency selective surface (106) and a reflective layer (110) on an inner surface (112) of the central concentric zone (102).

Abstract: 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 (12, 14 in a first embodiment and 102, 104 in a second embodiment). In the first embodiment, the outer concentric zone (14) is a frequency selective absorber (20) made of a metallic pattern (22) dimensioned to reflect signals in one frequency band and absorb signals in a second frequency band. In the second embodiment, the outer concentric zone (104) is a frequency selective surface (106) that reflects signals in one frequency band and passes signals in a second frequency bands. Resistance cards (122) overlay the top and bottom sides of the junction between the frequency selective surface (106) and a reflective layer (110) on an inner surface (112) of the central concentric zone (102).

Abstract: 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.

Abstract: 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 (12, 14 in a first embodiment and 102, 104 in a second embodiment). In the first embodiment, the outer concentric zone (14) is a frequency selective absorber (20) made of a metallic pattern (22) dimensioned to reflect signals in one frequency band and absorb signals in a second frequency band. In the second embodiment, the outer concentric zone (104) is a frequency selective surface (106) that reflects signals in one frequency band and passes signals in a second frequency bands. Resistance cards (122) overlay the top and bottom sides of the junction between the frequency selective surface (106) and a reflective layer (110) on an inner surface (112) of the central concentric zone (102).

Abstract: A multi-pattern reflector antenna for generating first and second antenna patterns from first and second RF signals having first and second frequencies of operation respectively. The antenna includes a reflector having a focal point, first and second subreflectors configured to image the focal point at first and second preselected locations respectively; and, first and second feeds positioned at the first and second preselected locations. The first and second feeds are configured to operate at the first and second frequencies of operation respectively and are operative to generate first and second radiated RF signals from the first and second RF signals respectively. The first and second subreflectors partially overlap each other with the first subreflector configured to be a frequency selective structure which reflects RF signals having the first frequency of operation and passes RF signals having the second frequency of operation.

Abstract: 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.

Abstract: A wideband matching surface (600) for a dielectric lens antenna (100) is formed from a first dielectric layer (602) (e.g., Rexolite™) characterized by a first refractive index and a second dielectric layer (604) characterized by a second refractive index supporting the first dielectric layer (602).

Abstract: 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.

Abstract: A wideband matching surface (600) for a dielectric lens antenna (100) is formed from a first dielectric layer (602) (e.g., Rexolite™) characterized by a first refractive index and a second dielectric layer (604) characterized by a second refractive index supporting the first dielectric layer (602).

Abstract: A phased antenna array (60) for use on a satellite, that employs a density tapering technique for positioning the antenna elements (62) in the array (60) to reduce co-channel interference between adjacent cells. Particularly, the spatial position of the various antenna elements (62) in the array (60) are spread out so that the center portion of the array (60) has the highest density of elements (62), and the outer portion of the array (60) has the lowest density of elements (62). Predetermined schemes are used to set the density of the elements (62) in the array (60). By providing fewer antenna elements (62) at the outer portion of the array (60), the beam side lobes are reduced.