Abstract: A compact multi-band ring-focus antenna system. The antenna system includes a first and a second main reflector 304, 306, each having a shaped surface of revolution about a common boresight axis (322) of the antenna. A first backfire type RF feed system (302, 312) is provided for feeding the first main reflector (304) on a first frequency band. A second RF feed (301) coaxial with the first RF feed (300) is provided for feeding the second main reflector (306) on a second frequency band spectrally offset from the first frequency band. Further a portion of the second RF feed passes through a first sub-reflectors (302) of the backfire feed. The second RF feed is terminated a distance from the first sub-reflector to illuminate a second sub-reflector (303).

Abstract: Antenna system (100) with dynamically adjustable ground plane spacing. The system includes at least one antenna radiating element (106, 108) and a first conductive ground plane (110, 120) spaced from radiating element (106, 108). The first conductive ground plane is comprised of a dielectric structure (104) containing a conductive fluid (120).

Abstract: A multiband phased array antenna includes a substrate, and dipole element arrays extending outwardly from an imaginary center point on the substrate. Each dipole element array includes dipole antenna elements arranged in an end-to-end relation and having a dipole size different than a dipole size of dipole antenna elements of at least one other dipole element array. A ground plane is adjacent the dipole element arrays and has a different spacing therefrom in an outward direction from the imaginary center point. The different spacing between the ground plane and the dipole element arrays increases from the imaginary center point towards an edge of the substrate.

Abstract: A phased array antenna includes a substrate, and an array of dipole antenna elements on the substrate. Each dipole antenna element includes a medial feed portion, and a pair of legs extending outwardly therefrom. Pairs of adjacent legs of adjacent dipole antenna elements include respective spaced apart end portions. The phased array antenna further includes selectable impedance elements and switches. Each switch is for selectively coupling at least one impedance element between a respective pair of adjacent legs of adjacent dipole antenna elements for changing the capacitive coupling therebetween.

Abstract: A phased array antenna includes a substrate having a first surface, and a second surface adjacent thereto and defining an edge therebetween. A plurality of dipole antenna elements are on the first surface, and at least a portion of at least one dipole antenna element is on the second surface. Each dipole antenna element includes a medial feed portion and a pair of legs extending outwardly therefrom. Adjacent legs of adjacent dipole antenna elements on the first and second surfaces include respective spaced apart end portions having predetermined shapes and relative positioning for providing increased capacitive coupling between the adjacent dipole antenna elements.

Abstract: A phased array antenna includes a substrate, and an array of dipole antenna elements on the substrate. Each dipole antenna element comprises a medial feed portion, and a pair of legs extending outwardly therefrom, and adjacent legs of adjacent dipole antenna elements include respective spaced apart end portions. A respective impedance element is electrically connected between the spaced apart end portions of adjacent legs of adjacent dipole antenna elements for providing increased capacitive coupling therebetween.

Abstract: Method and apparatus for feeding a compact main reflector of an RF antenna on a plurality of spectrally offset frequency bands. The method can include the steps of forming a focal ring for a main reflector (304) by positioning an RF source (301) at a first frequency within a first frequency band in the far field relative to a shaped non-linear surface of revolution so that the shaped non-linear surface of revolution forms a subreflector (302). A second focal ring can be formed for the main reflector (304) by positioning a second RF source (300) in the nearfield of the shaped non-linear surface of revolution.

Abstract: Method and apparatus for feeding a compact main reflector of an RF antenna on a plurality of spectrally offset frequency bands. The method can include the steps of forming a focal ring for a main reflector (304) by positioning an RF source (301) at a first frequency within a first frequency band in the far field relative to a shaped non-linear surface of revolution so that the shaped non-linear surface of revolution forms a subreflector (302). A second focal ring can be formed for the main reflector (304) by positioning a second RF source (300) in the nearfield of the shaped non-linear surface of revolution.

Abstract: A phased array antenna (10) includes a current sheet array (20) on a substrate (23), at least one dielectric layer (24) between the current sheet array and a ground plane (30), and at least one conductive plane (25) adjacent to the substrate for providing additional coupling between adjacent dipole antenna elements of the current sheet array.

Abstract: An array of radiating elements including a first set of antenna elements in an array configuration and a second set of antenna elements in an array configuration. The first set of antenna elements is positioned below the second set of antenna elements with the first set acting as an effective ground plane for the second set. The first set of antenna elements are aligned in a first planar grid pattern of spaced rows and columns and the second set of antenna elements are aligned in a second similar grid pattern rotated at a 45 degree angle relative to the first grid pattern. The array can be configured for wideband operation by having the first band of frequencies adjacent to the second band of frequencies. The array can include a dielectric material interposed between the first plurality of antenna elements and the second plurality of antenna elements.

Abstract: A phased array antenna(10) includes a current sheet array (20) on a substrate (23), at least one dielectric layer (24) between the current sheet array and a ground plane (30), and at least one conductive plane (25) adjacent to the substrate for providing additional coupling between adjacent dipole antenna elements of the current sheet array.

Abstract: A dual-polarized, stub-tuned, proximity-fed, stacked patch antenna includes a ground plane layer and a dielectric substrate overlying the ground plane layer. An active patch antenna element is disposed on the dielectric substrate. A parasitic patch antenna element is supported in spaced relation to the active patch antenna element. Dual feed lines are spaced from and field-coupled to the active patch antenna element. Each feed line has a tuning stub for producing a distributed antenna resonance. The dual feed lines are configured to provide dual polarization and minimize coupling between the feed lines. The feed lines are positioned substantially orthogonal to each other to provide orthogonal linear polarizations. Each feed line includes a feed line tip that extends towards the center of the active patch antenna element and spaced from each other to minimize tip-to-tip coupling. Each feed line tip includes a 90 degree bend.

Abstract: A ring focus antenna and method of using same. The ring focus antenna can have a main reflector of revolution shaped as a non-regular paraboloid about a boresight axis of the antenna. A sub-reflector/feed pair is provided comprising a sub-reflector of revolution shaped as a non-regular ellipsoid having a ring-shaped focal point about the boresight axis. A feed element is installed at a feed element location separated spaced from a vertex of the sub-reflector on the boresight axis of the antenna. The main reflector is adapted for operation with multiple sub-reflector/feed pairs having a coupled configuration, and multiple sub-reflector/feed pairs having a decoupled configuration (i.e. classical optical dual reflector system). The main reflector is operable at a plurality of spectrally offset frequency bands. For example, the antenna can be designed for operation over C-band, X-band, Ku-band, and Ka-band.

Abstract: A ring focus antenna and method of using same. The ring focus antenna can have a main reflector of revolution shaped as a non-regular paraboloid about a boresight axis of the antenna. A sub-reflector/feed pair is provided comprising a sub-reflector of revolution shaped as a non-regular ellipsoid having a ring-shaped focal point about the boresight axis. A feed element is installed at a feed element location separated spaced from a vertex of the sub-reflector on the boresight axis of the antenna. The main reflector is adapted for operation with multiple sub-reflector/feed pairs having a coupled configuration, and multiple sub-reflector/feed pairs having a decoupled configuration (i.e. classical optical dual reflector system). The main reflector is operable at a plurality of spectrally offset frequency bands. For example, the antenna can be designed for operation over C-band, X-band, Ku-band, and Ka-band.

Abstract: A dual-polarized, stub-tuned, proximity-fed, stacked patch antenna includes a ground plane layer and a dielectric substrate overlying the ground plane layer. An active patch antenna element is disposed on the dielectric substrate. A parasitic patch antenna element is supported in spaced relation to the active patch antenna element. Dual feed lines are spaced from and field-coupled to the active patch antenna element. Each feed line has a tuning stub for producing a distributed antenna resonance. The dual feed lines are configured to provide dual polarization and minimize coupling between the feed lines. The feed lines are positioned substantially orthogonal to each other to provide orthogonal linear polarizations. Each feed line includes a feed line tip that extends towards the center of the active patch antenna element and spaced from each other to minimize tip-to-tip coupling. Each feed line tip includes a 90 degree bend.

Abstract: An array of radiating elements including a first set of antenna elements in an array configuration and a second set of antenna elements in an array configuration. The first set of antenna elements is positioned below the second set of antenna elements with the first set acting as an effective ground plane for the second set. The first set of antenna elements are aligned in a first planar grid pattern of spaced rows and columns and the second set of antenna elements are aligned in a second similar grid pattern rotated at a 45 degree angle relative to the first grid pattern. The array can be configured for wideband operation by having the first band of frequencies adjacent to the second band of frequencies. The array can include a dielectric material interposed between the first plurality of antenna elements and the second plurality of antenna elements.

Abstract: The invention concerns a method and apparatus for reducing mutual coupling among adjacent planar antenna radiating elements in an array. The elements can be positioned adjacent to one another in a standard geometric array configuration. A circumferential conductive metal line is provided in the plane of each element at an outer perimeter thereof. The conductive metal line is electrically connected to a ground potential. The ground plane potential is preferably provided by a ground plane reflector over which the antenna elements are suspended. The conductive metal line can be connected to the ground plane reflector by one or more ground posts extending between the conductive metal line and the ground plane reflector.

Abstract: The invention concerns a method and apparatus for reducing mutual coupling among adjacent planar antenna radiating elements in an array. The elements can be positioned adjacent to one another in a standard geometric array configuration. A circumferential conductive metal line is provided in the plane of each element at an outer perimeter thereof. The conductive metal line is electrically connected to a ground potential. The ground plane potential is preferably provided by a ground plane reflector over which the antenna elements are suspended. The conductive metal line can be connected to the ground plane reflector by one or more ground posts extending between the conductive metal line and the ground plane reflector.

Abstract: The invention concerns an array of radiating elements. A first plurality of antenna elements in a first plane in an array configuration is configured for operating on a first band of frequencies. A second plurality of planar antenna elements in an array configuration is configured for operating on a second frequency band, the second plurality of antenna elements is also positioned in the first plane. A first effective ground plane is provided for the first plurality of antenna elements and a second effective ground plane is provided for the second plurality of antenna elements. A first spacing between the first plurality of elements and the first effective ground plane is different from a second spacing between the second plurality of elements and the second effective ground plane. According to one embodiment, the second plurality of elements are adjacent to one another in a unitary cluster that is disposed within the first plurality of elements.

Abstract: A spaceborne hybrid antenna reflector for dual frequency band illumination of common spot beam coverage regions contains an interior solid reflector region, that is adjacent at its perimeter to a ring-shaped exterior dichroic reflector region and adjoined by a common backing structure. The solid interior region is reflective to RF energy at each of first and second spaced apart frequency bands, while the exterior dichroic reflector region is reflective at the first frequency band, but non-reflective at the second frequency band. This allows the hybrid reflector to realize the same beamwidth coverage for a transmitter operating at one frequency band and a receiver operating at the other frequency band. The backing support frame at the rear side of the reflector is electrically decoupled from the exterior dichroic ring.