Multiple ridge antenna
First Claim
1. A variable-polarization microwave antenna for sending and receiving microwaves at frequencies within a predetermined frequency range, the antenna comprising:
- A. first and second generally planar ground-plane conductors spaced apart and extending substantially parallel to each other, said first ground-plane conductor having an aperture therethrough and including first and second pairs of elongated ridges extending into said aperture and oriented perpendicular to each other, the ridges of each pair extending toward each other from opposite sides of said aperture and leaving a gap therebetween;
B. shorting elements extending between said ground-plane conductors and surrounding said aperture to form a cavity defined by said shorting elements and said ground-plane conductors, the distances across said cavity in the directions of said ridges being between one-half and one wavelength at frequencies within the predetermined frequency range;
C. a first feed line including a first elongated feed conductor extending between and generally parallel to said ground-plane conductors and into said cavity substantially in registration with the ridges of said first pair and across the gap therebetween; and
D. a second feed line including a second elongated feed conductor extending between and generally parallel to said ground-plane conductors and into said cavity substantially in registration with the ridges of said second pair and across the gap therebetween, said first and second feed conductors being electrically isolated from each other.
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Accused Products
Abstract
A microwave antenna (10) is excited by two independently driven feed lines (30 and 32) so that the plane of polarization of the resultant microwave radiation depends on the relative amplitudes of the signals on the two feed lines. The feed lines are disposed between two parallel ground planes (12 and 14), in one of which is etched an aperture (18). The periphery of the aperture forms ridges (20, 22, 24, and 26) in registration with the feed lines (30 and 32). Conductive eyelets (27) extend between the ground-plane conductors (12 and 14) to act as shorting elements that surround the aperture to form a cavity defined by the shorting elements and the ground-plane conductors. The resultant antenna, which may, for instance, have a thickness of only one-tenth of a wavelength, achieves a 2:1 VSWR bandwidth on the order of 30%.
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Citations
27 Claims
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1. A variable-polarization microwave antenna for sending and receiving microwaves at frequencies within a predetermined frequency range, the antenna comprising:
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A. first and second generally planar ground-plane conductors spaced apart and extending substantially parallel to each other, said first ground-plane conductor having an aperture therethrough and including first and second pairs of elongated ridges extending into said aperture and oriented perpendicular to each other, the ridges of each pair extending toward each other from opposite sides of said aperture and leaving a gap therebetween; B. shorting elements extending between said ground-plane conductors and surrounding said aperture to form a cavity defined by said shorting elements and said ground-plane conductors, the distances across said cavity in the directions of said ridges being between one-half and one wavelength at frequencies within the predetermined frequency range; C. a first feed line including a first elongated feed conductor extending between and generally parallel to said ground-plane conductors and into said cavity substantially in registration with the ridges of said first pair and across the gap therebetween; and D. a second feed line including a second elongated feed conductor extending between and generally parallel to said ground-plane conductors and into said cavity substantially in registration with the ridges of said second pair and across the gap therebetween, said first and second feed conductors being electrically isolated from each other. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 16, 17)
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12. A microwave antenna for sending and receiving microwaves at frequencies within a predetermined frequency range, the antenna comprising:
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A. first and second generally planar ground-plane conductors spaced apart and extending substantially parallel to each other, said first ground-plane conductor having an aperture therethrough and including a pair of elongated ridges extending into said aperture, each ridge having a round end, said ridges extending toward each other from opposite sides of said aperture and leaving a gap therebetween; B. shorting elements extending between said ground-plane conductors and surrounding said aperture to form a cavity defined by said shorting elements and said ground-plane conductors; and C. a feed line including an elongated feed conductor extending between and generally parallel to said ground-plane conductors and into said cavity substantially in registration with said ridges and across said gap therebetween. - View Dependent Claims (13, 14, 15, 18, 19, 20, 21, 22)
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23. A microwave antenna for sending and receiving microwaves at frequencies within a predetermined frequency range, the antenna comprising:
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A. first and second generally planar ground-plane conductors spaced apart and extending substantially parallel to each other, said first ground-plane conductor having an aperture therethrough and including a pair of elongated ridges extending into said aperture, said ridges extending toward each other from opposite sides of said aperture and leaving a gap therebetween; B. shorting elements extending between said ground-plane conductors and surrounding said aperture to form a cavity defined by said shorting elements and said ground-plane conductors, the distance across said cavity in the direction of said ridges being between one-half and one wavelength at frequencies within the predetermined frequency range; C. a feed line including an elongated feed conductor extending between and generally parallel to said ground-plane conductors and into said cavity substantially in registration with said ridges and across said gap therebetween; and D. shorting elements extending between said ground-plane conductors along the longitudinal edges of said ridges. - View Dependent Claims (24)
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25. An antenna, comprising:
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first and second generally planar ground-plane conductors spaced apart and extending substantially parallel to each other, said first ground-plane conductor having an aperture therethrough and including a pair of elongated ridges extending into said aperture, said ridges extending toward each other from opposite sides of said aperture and leaving a gap therebetween; a feed line extending between and generally parallel to said ground-plane conductors substantially in registration with said ridges and across said gap therebetween; and shorting elements extending between said ground-plane conductors along the longitudinal edges of said ridges.
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26. An antenna, comprising:
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first and second generally planar ground-plane conductors spaced apart and extending substantially parallel to each other, said first ground-plane conductor having an aperture therethrough and including a plurality of pairs of elongated ridges extending into said aperture, the ridges of each pair extending toward each other from opposite sides of said aperture and leaving a gap therebetween; shorting elements extending between said ground-plane conductors and surrounding said aperture to form a cavity defined by said shorting elements and said ground-plane conductors; and a like plurality of feed lines, each feed line including an elongated feed conductor extending between and generally parallel to said ground-plane conductors and into said cavity substantially in registration with the ridges of a pair and across the gap therebetween. - View Dependent Claims (27)
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Specification