Conical omni-directional coverage multibeam antenna with parasitic elements
First Claim
1. An antenna system comprising:
- a plurality of radiating structures spaced circumferentially around a center point, each radiating structure of said plurality of radiating structures being spaced equidistant from and parallel to a next adjacent radiating structure;
a plurality of passive structures spaced circumferentially around said center point, each passive structure of said plurality of passive structures being spaced equidistant from and parallel to a next adjacent passive structure;
a ground surface circumferentially located around said center point and between said center point and each of said radiating structures, said ground surface also being located between said center point and each of passive structures; and
means for phase shifting a transmission signal from certain activated radiating structures a selected delay amount, the phase shift amount being selected such that the transmission signal wave front leaving said activated radiating structures is in a relatively straight line substantially perpendicular to the direction of travel of said transmission signal, the direction of travel being normal to a point on the ground surface corresponding to one of said activated radiating structures.
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Accused Products
Abstract
An omni directional coverage multibeam antenna relief on a ground surface having simple conical shapes to provide beam steering. One advantage of such a system is that the projected area is always constant and broadside to the intended direction resulting in limited scan loss effects. In the case of a cylinder as the conical shape, z-axis symmetry provides a constant antenna aperture projection in any azimuthal direction. Using this geometry, high level, side lobes are reduced considerably because of the natural aperture tapering from dispersion effects. These side lobes are further reduced by the presence of parasitic elements which also result in the added benefit of an increased front and back ratio. This front to back ratio may be further increased by the use of inverted cosine energization of selected antenna elements. Coverage area and power can be controlled by changing the ground surface angle and by selectively activating different antenna beam positions around the circumference of the ground surface, and by selectively changing the phase relationship between a given set of antenna beams.
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Citations
104 Claims
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1. An antenna system comprising:
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a plurality of radiating structures spaced circumferentially around a center point, each radiating structure of said plurality of radiating structures being spaced equidistant from and parallel to a next adjacent radiating structure; a plurality of passive structures spaced circumferentially around said center point, each passive structure of said plurality of passive structures being spaced equidistant from and parallel to a next adjacent passive structure; a ground surface circumferentially located around said center point and between said center point and each of said radiating structures, said ground surface also being located between said center point and each of passive structures; and means for phase shifting a transmission signal from certain activated radiating structures a selected delay amount, the phase shift amount being selected such that the transmission signal wave front leaving said activated radiating structures is in a relatively straight line substantially perpendicular to the direction of travel of said transmission signal, the direction of travel being normal to a point on the ground surface corresponding to one of said activated radiating structures. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 39, 40)
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30. A selectively directional antenna system comprising:
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a plurality of radiating structures spaced circumferentially around a center point; a plurality of passive structures spaced circumferentially around said center point; and a ground surface circumferentially located around said center point and between said center point and each of said radiating structures, said ground surface also being located between said center point and each of said passive structures, said ground surface circumscribing a volume substantially perpendicular to a surface upon which signals transmitted from a radiating structure are to be received on. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62)
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63. A method of operating an antenna system having a plurality of radiating structures spaced circumferentially around a center point, each radiating structure spaced equidistant from and parallel to a next adjacent radiating structure, said antenna system also having a plurality of parasitic structures spaced circumferentially around the center point, each parasitic structure spaced equidistant from and parallel to a next adjacent parasitic structure, each parasitic structure also spaced equidistant from and parallel to each radiating structure of a pair of said radiating structures, wherein a ground surface is circumferentially located around the center point and between the center point and each of the radiating structures and the ground surface is also located between the center point and each of the parasitic structures, the method comprising the steps of:
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activating ones of said plurality of radiating structures; delaying a transmission signal from certain of the activated radiating structures a selected delay amount; and selecting the delay amount such that the transmission signal wave front leaving the activated radiating structures including energy reflected from ones of said plurality of parasitic structures is in a relatively straight line substantially perpendicular to the direction of desired travel of the transmission signal. - View Dependent Claims (64, 65, 66, 67, 68, 69, 70, 71, 72)
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73. A method of constructing an antenna system comprising the steps of:
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establishing a ground surface circumferentially located around a mast, said ground surface circumscribing a volume substantially perpendicular to a surface upon which signals transmitted from a radiating structure are to be received on; positioning a plurality of antenna structures at spaced intervals circumferentially around the ground surface; and positioning a plurality of parasitic structures at spaced intervals circumferentially around the ground surface. - View Dependent Claims (74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93)
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94. A method of energizing an antenna array to result in a far field radiation pattern having acceptably small side lobes in relation to a main lobe, said antenna array having a plurality of radiating structures spaced circumferentially around a center point, said antenna system also having a plurality of parasitic structures spaced circumferentially around the center point, wherein a ground surface is circumferentially located around the center point and between the center point and each of the radiating structures, and wherein the ground surface is also located between the center point and each of the parasitic structures, the method comprising the steps of:
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selecting ones of said plurality of radiating structures to energize, said selected radiating structures being adjacent radiating structures in said plurality of radiating structures, said selected radiating structures forming a sub-array of antenna elements having at least two outer most radiating structures, wherein said sub-array of antenna elements have associated therewith ones of said plurality of parasitic structures; and energizing said sub-array utilizing a plurality of energy levels, ones of said plurality of energy levels being applied to radiating structures of said sub-array such that a largest energy level is applied to said two outer most radiating structures. - View Dependent Claims (95, 96, 97, 98, 99, 100, 101, 102, 103, 104)
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Specification