Transmission line notch antenna
First Claim
1. An antenna element (30) including:
- a transmission line (36) having;
a conductive layer (60);
a conductive member (58) adjacent said conductive layer; and
dielectric spacing means (62) between said conductive layer and said conductive member, said transmission line further having;
a first transmission line end (34) for connection to RF means;
a second transmission line end (72);
a transmission line connecting portion (42 &
44) extending from said first transmission line end; and
a transmission line notch portion (46) extending from said second transmission line end to said transmission line connecting portion; and
a conductor (50) having;
a first conductor end (78);
a second conductor end (72);
a conductor connecting portion extending from said first conductor end (52 &
54); and
a conductor notch portion (56) extending from said second conductor end to said conductor connecting portion, said transmission line notch portion is shaped in a first curve extending from said second transmission line end and said conductor notch portion is shaped in a second curve that is generally a mirror image of said first curve extending from said second conductor end, an RF energy field is set up across said transmission line notch portion and said conductor notch portion, said conductive member at said second transmission line end being electrically connected to said second conductor end so that said transmission line notch portion of said conductive layer and said conductor notch portion of said conductor form a RF active notch structure (from 72 to
74) for radiating said RF energy field in a direction away from said RF active notch structure and for transitioning the characteristic impedance of said transmission line to that of air.
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Accused Products
Abstract
Non-resonant, end fire antennae that operate over broad frequency bands, can be incorporated into arrays and have low RF cross-sections are constructed from a transmission line, usually a piece of coaxial cable that if it is not self supporting, is mounted on or in a lightweight structural material with an outer end with a sheath or stripline the shape of half of a notch. The other half of the notch is formed from a conductor electrically connected to the center conductor of the coaxial cable. The cable and conductor are variably spaced to transition the characteristic impedance of the cable to that of free space. The conductor and the sheath are terminated either with ground connections or by inductive loads.
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Citations
32 Claims
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1. An antenna element (30) including:
- a transmission line (36) having;
a conductive layer (60); a conductive member (58) adjacent said conductive layer; and dielectric spacing means (62) between said conductive layer and said conductive member, said transmission line further having; a first transmission line end (34) for connection to RF means; a second transmission line end (72); a transmission line connecting portion (42 &
44) extending from said first transmission line end; anda transmission line notch portion (46) extending from said second transmission line end to said transmission line connecting portion; and a conductor (50) having; a first conductor end (78); a second conductor end (72); a conductor connecting portion extending from said first conductor end (52 &
54); anda conductor notch portion (56) extending from said second conductor end to said conductor connecting portion, said transmission line notch portion is shaped in a first curve extending from said second transmission line end and said conductor notch portion is shaped in a second curve that is generally a mirror image of said first curve extending from said second conductor end, an RF energy field is set up across said transmission line notch portion and said conductor notch portion, said conductive member at said second transmission line end being electrically connected to said second conductor end so that said transmission line notch portion of said conductive layer and said conductor notch portion of said conductor form a RF active notch structure (from 72 to
74) for radiating said RF energy field in a direction away from said RF active notch structure and for transitioning the characteristic impedance of said transmission line to that of air. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
- a transmission line (36) having;
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11. An antenna (80) including:
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a first antenna element (82) having; a transmission line having; an conductive layer (108); a conductive member (124) within said conductive layer; and dielectric spacing means (188) between said conductive layer and said conductive member, said transmission line further having; a first transmission line end (92) for connection to RF means; a second transmission line end (128); a transmission line connecting portion extending from said first transmission line end (96); and a transmission line notch portion (108) extending from said second transmission line end to said transmission line connecting portion; and a conductor having; a second conductor end (128); and a conductor notch portion (120) extending from said second conductor end, said transmission line notch portion is shaped in a first curve extending from said second transmission line end and said conductor notch portion is shaped in a second curve that is generally a mirror image of said first curve extending from said second conductor end, an RF energy field is set up across said transmission line notch portion and said conductor notch portion, said conductive member at said second transmission line end being electrically connected to said second conductor end so that said transmission line notch portion of said conductive layer and said conductor notch portion of said conductor form an RF active notch structure for radiating said RF energy field in a direction away from said RF active notch structure and for transitioning the characteristic impedance of said transmission line to that of air; and a second antenna element (82) having; a transmission line having; an conductive layer; a conductive member within said conductive layer; and dielectric spacing means between said conductive layer and said conductive member, said transmission line further having; a first transmission line end for connection to RF means; a second transmission line end; a transmission line connecting portion extending from said first transmission line end; and a transmission line notch portion extending from said second transmission line end to said transmission line connecting portion; and a conductor having; a second conductor end; and a conductor notch portion extending from said second conductor end, said transmission line notch portion is shaped in a first curve extending from said second transmission line end and said conductor notch portion is shaped in a second curve that is generally a mirror image of said first curve extending from said second conductor end, an RF energy field is set up across said transmission line notch portion and said conductor notch portion, said conductive member at said second transmission line end being electrically connected to said second conductor end so that said transmission line notch portion of said conductive layer and said conductor notch portion of said conductor form an RF active notch structure for radiating said RF energy field in a direction away from said RF active notch structure and for transitioning the characteristic impedance of said transmission line to that of air, said first and second antenna elements being positioned generally at right angles to each other with said RF active notch structures adjacent. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. An antenna element (30) including:
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a coaxial cable (36) having; a conductive sheath (60); a center conductor (58); a first cable end (34) for connection to RF means; a second cable end (72); a cable connecting portion (42 &
46) extending from said first cable end; anda cable notch portion (46) extending from said second cable end to said cable connecting portion; and a wire (50) having; a first wire end (78); a second wire end (72); a wire connecting portion (52 &
54) extending from said first wire end; anda wire notch portion (56) extending from said second wire end to said wire connecting portion, said coaxial cable notch portion is shaped in a first curve extending from said second coaxial cable end and said wire notch portion is shaped in a second curve that is generally a mirror image of said first curve extending from said second wire end, an RF energy field is set up across said coaxial cable notch portion and said wire notch portion, said center conductor at said second cable end being electrically connected to said second wire end so that said cable notch portion of said coaxial cable and said wire notch portion of said wire form an RF active notch structure for radiating said RF energy field in a direction away from said RF active notch structure and for transitioning the characteristic impedance of said coaxial cable to that of air. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32)
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Specification