Staggered helical array antenna
First Claim
1. An array antenna comprising:
- a mounting base;
a plurality of helical radiators disposed in an array and extending forward of said mounting base, each of said radiators having a feed connection point located at a distance from said mounting base, each of said radiators comprising a radiating element disposed about an axis extending forward of said base, said radiators being arranged in said array with their respective axes spaced apart from each other; and
means connected between said mounting base and individual ones of said radiators for staggering the distances of said feed connection points of said radiators from said mounting base, said staggering reducing mutual coupling among said radiators;
wherein said feed connection points of alternate ones of said radiators in said array are staggered in location relative to said feed connection points of other ones of said radiators in said array; and
the distance of staggering is equal approximately to a spacing between turns of a helix in any one of said radiators.
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Accused Products
Abstract
An antenna composed of an array of helical radiators has, in accordance with a methodology of the invention, a physical structure for reducing mutual coupling between closely spaced radiators so as to permit a reduction in spacing of the radiators. The radiators are mounted upon a mounting base, such as a ground plane element, with the helical radiators extending forward of the mounting base. Distances between the radiators and the mounting base are staggered in an amount approximately equal to one turn of a helix. The stagger distance corresponds approximately to one quarter of a free-space wavelength. The staggering significantly reduces the mutual coupling so as to permit closer spacing of the helical radiators such as, by way of example, in the formation of a feed directing radiant energy to a reflector of the antenna.
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Citations
16 Claims
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1. An array antenna comprising:
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a mounting base; a plurality of helical radiators disposed in an array and extending forward of said mounting base, each of said radiators having a feed connection point located at a distance from said mounting base, each of said radiators comprising a radiating element disposed about an axis extending forward of said base, said radiators being arranged in said array with their respective axes spaced apart from each other; and means connected between said mounting base and individual ones of said radiators for staggering the distances of said feed connection points of said radiators from said mounting base, said staggering reducing mutual coupling among said radiators; wherein said feed connection points of alternate ones of said radiators in said array are staggered in location relative to said feed connection points of other ones of said radiators in said array; and the distance of staggering is equal approximately to a spacing between turns of a helix in any one of said radiators. - View Dependent Claims (2, 3, 4)
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5. An array antenna comprising:
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a mounting base; a plurality of helical radiators disposed in an array and extending forward of said mounting base, each of said radiators having a feed connection point located at a distance from said mounting base, each of said radiators comprising a radiating element disposed about an axis extending forward of said base, said radiators being arranged in said array with their respective axes spaced apart from each other; and means connected between said mounting base and individual ones of said radiators for staggering the distances of said feed connection points of said radiators from said mounting base, said staggering reducing mutual coupling among said radiators; wherein said feed connection points of alternate ones of said radiators in said array are staggered in location relative to said feed connection points of other ones of said radiators in said array; each of said radiators has the same helical pitch; a spacing between turns of helix in any one of said radiators is equal approximately to one-quarter of a free-space wavelength of radiation to be radiated from said antenna; and said distance of staggering is equal approximately to said spacing between turns. - View Dependent Claims (6, 7)
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8. A method of reducing mutual coupling between helical radiators of an array antenna comprising steps of:
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mounting said radiators parallel to each other on a mounting base of said antenna, each of said radiators having a feed connection point located at a distance from said mounting base, each of said radiators comprising a radiating element disposed about an axis extending forward of said base, said mounting including an arranging of said radiators in an array with their respective axes spaced apart from each other; and staggering the distances between said feed connection points and said base to provide for greater and lesser amounts of the distances; wherein said staggering of distances provides a distance of staggering which is equal approximately to a spacing between turns of a helix in any one of said radiators. - View Dependent Claims (9, 10)
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11. A method of reducing mutual coupling between helical radiators of an array antenna comprising steps of:
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mounting said radiators parallel to each other on a mounting base of said antenna, each of said radiators having a feed connection point located at a distance from said mounting base, each of said radiators comprising a radiating element disposed about an axis extending forward of said base, said mounting including an arranging of said radiators in an array with their respective axes spaced apart from each other; and staggering the distances between said feed connection points and said base to provide for greater and lesser amounts of the distances; wherein, in each of said radiators, said feed connection point is located at an end of the radiator facing said mounting base, and said staggering is accomplished by staggering distances between said radiators and said mounting base; and said distances are equal approximately to a spacing between turns of a helix of one of said radiators, and the helices of the respective radiators are equal in length.
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12. A method of reducing mutual coupling between helical radiators of an array antenna comprising steps of:
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mounting said radiators parallel to each other on a mounting base of said antenna, each of said radiators having a feed connection point located at a distance from said mounting base, each of said radiators comprising a radiating element disposed about an axis extending forward of said base, said mounting including an arranging of said radiators in an array with their respective axes spaced apart from each other; and staggering the distances between said feed connection points and said base to provide for greater and lesser amounts of the distances; wherein said distances are equal approximately to a spacing between turns of a helix of one of said radiators.
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13. An array antenna comprising:
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a mounting base; a plurality of radiators having equal periodic slow-wave structures disposed in an array and extending forward of said mounting base for radiating radiation as end-fire radiators, each of said radiators having a feed connection point disposed at a distance from said mounting base, each of said radiators comprising a radiating element disposed about an axis extending forward of said base, said radiators being arranged in said array with their respective axes spaced apart from each other; wherein the distances of said feed connection points of said radiators from said mounting base are staggered, staggering of said distances reducing mutual coupling among said radiators, the distances of a first plurality of said feed connection points from said mounting base being different from the distances of a second plurality of said feed connection points from said mounting base; and the distance of staggering is equal approximately to the periodicity of the slow-wave structure in any one of said radiators.
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14. An array antenna comprising:
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a mounting base; a plurality of radiators having equal periodic slow-wave structures disposed in an array and extending from said mounting base for radiating radiation as end-fire radiators, each of said radiators having a feed connection point spaced from said mounting base, each of said radiators comprising a radiating element disposed about an axis extending forward of said base, said radiators being arranged in said array with their respective axes spaced apart from each other; wherein said feed connection points of individual ones of said radiators in said array differ in spacing from said mounting base; and the difference of spacing is equal approximately to the periodicity of the slow-wave structure in any one of said radiators.
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15. An array antenna comprising:
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a mounting base; a plurality of helical radiators disposed in an array and extending forward of said mounting base, each of said radiators having a feed connection point, each of said radiators comprising a radiating element disposed about an axis extending forward of said base, said radiators being arranged in said array with their respective axes spaced apart from each other; means connected between said mounting base and individual ones of said radiators for staggering distances of said feed connection points of said radiators from said mounting base, said staggering reducing mutual coupling among said radiators; wherein said feed connection points of individual ones of said radiators in said array differ in distance from said mounting base; and the distance of staggering is equal approximately to a spacing between turns of a helix in any one of said radiators.
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16. A method of reducing mutual coupling among radiators in an array of radiators of an antenna, the radiators having equal periodic slow-wave structures;
- the method comprising steps of
mounting said radiators on a base of said antenna with the radiators extending from said base, each of said radiators comprising a radiating element disposed about an axis extending forward of said base, said mounting including an arranging of said radiators in the array with their respective axes spaced apart from each other; providing each of said radiators with a feed connection point spaced from said base; adjusting each of said radiators to stagger spacings between said feed connection points and said base for greater and lesser amounts of the spacings between various ones of said feed connection points and said base; and wherein said staggering of spacings provides a stagger spacing which is equal approximately to the periodicity of the slow-wave structure in any one of said radiators.
- the method comprising steps of
Specification