Microstrip antenna employing width discontinuities
First Claim
1. A microstrip antenna, comprising:
- a ground plane;
a dielectric layer having a first surface overlying said ground plane, and a second surface opposing said first surface;
a substantially planar and electrically conductive layer overlying said second surface, said electrically conductive layer including a plurality of substantially co-planar patches of differing widths, each of said plurality of patches being connected via one or more junctions to at least another of said plurality patches;
a first patch among said plurality of patches is disposed between opposing edges of a second patch and a third patch of said plurality of patches, wherein said first patch has a narrower width compared to widths of said second and third patches so that respective junctions formed between the first and second patch, and the first and third patch define discontinuities in width therebetween;
a feed disposed in the first patch and configured to connect to a coaxial cable; and
wherein said respective junctions formed between the first and second patch, and the first and the third patch are symmetrically disposed about the first patch.
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Accused Products
Abstract
An apparatus and method to reduce the size of a microstrip antenna without sacrificing antenna efficiency too much are described. The antenna structure includes discontinuity of strip width in the middle of the antenna patch to reduce the size of the antenna at a given resonant frequency. The antenna structure further includes a plurality of patches of differing widths connected to each other at junctions. The junctions are placed symmetrically to ensure maximum radiation at the boresight and also to further reduce cross-polarization levels. A coaxial feed is connected at a predetermined location near the center of a patch, having a narrower width, in order to match the input impedance of the antenna to the coaxial feed.
127 Citations
30 Claims
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1. A microstrip antenna, comprising:
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a ground plane;
a dielectric layer having a first surface overlying said ground plane, and a second surface opposing said first surface;
a substantially planar and electrically conductive layer overlying said second surface, said electrically conductive layer including a plurality of substantially co-planar patches of differing widths, each of said plurality of patches being connected via one or more junctions to at least another of said plurality patches;
a first patch among said plurality of patches is disposed between opposing edges of a second patch and a third patch of said plurality of patches, wherein said first patch has a narrower width compared to widths of said second and third patches so that respective junctions formed between the first and second patch, and the first and third patch define discontinuities in width therebetween;
a feed disposed in the first patch and configured to connect to a coaxial cable; and
wherein said respective junctions formed between the first and second patch, and the first and the third patch are symmetrically disposed about the first patch. - View Dependent Claims (2, 3, 4, 5, 6, 7, 29, 30)
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8. A microstrip antenna, comprising:
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a ground plane;
a dielectric layer having a first surface overlying said ground plane, and a second surface opposing said first surface;
an electrically conductive layer overlying said second surface, said electrically conductive layer including a plurality of patches of differing widths, each of said plurality of patches being connected via one or more junctions to at least another of said plurality of patches;
a first patch among said plurality of patches is disposed between opposing edges of a second patch and a third patch of said plurality of patches, wherein said first patch has a narrower width compared to widths of said second and third patches so that respective junctions formed between the first and second patch, and the first and third patch define discontinuities in width therebetween;
a feed disposed in the first patch and configured to connect to a coaxial cable; and
wherein said respective junctions formed between the first and second patch, and the third patches each have additional radiating edges .
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9. In an electrically short microstrip antenna having a ground plane, a dielectric layer, a substantially planar and electrically conductive layer overlying a surface of the dielectric layer, a method of reducing size of the microstrip antenna comprising:
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providing a plurality of substantially co-planar patches of differing widths on the conductive layer;
connecting said plurality of patches to adjacent patches at one or more junctions, said connecting step including, disposing a first patch among said plurality of patches between opposing edge of a second patch and a third patch of said plurality of patches, wherein said first patch has a narrower width compared to widths of said second and third patches, so that respective junctions formed between the first and second patch, and the first and third patch define discontinuities in width therebetween; and
symmetrically placing said one or more junctions about said first patch so as to ensure maximum radiation at antenna boresight and to reduce cross-polarization levels. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. In an electrically short microstrip antenna having a ground plane, a dielectric layer, an electrically conductive layer overlying a surface of the dielectric layer, a method of reducing size of the microstrip antenna comprising:
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providing a plurality of patches of differing widths on the conductive layer;
connecting said plurality of patches to adjacent patches at one or more junctions, said connecting step including, disposing a first patch among said plurality of patches between opposing edges of a second patch and a third patch of said plurality of patches, wherein said first patch has a narrower width compared to widths of said second and third patches, so that respective junctions formed between the first and second patch, and the first and third patch define discontinuities in width therebetween;
symmetrically placing said one or more junctions about said first patch so as to ensure maximum radiation at antenna boresight and to reduce cross-polarization levels; and
providing the second and third patches with additional radiating edges.
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18. A microstrip antenna, comprising:
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a ground plane;
a dielectric layer having a first surface overlying said ground plane, and a second surface opposing said first surface;
a plurality of substantially co-planar patches of differing widths disposed on a substantially planar conductive layer on said dielectric layer;
means for connecting said plurality of patches to adjacent patches at one or more junctions, a first patch among said plurality of patches being disposed between opposing edges of a second patch and a third patch, wherein said first patch has a narrower width compared to widths of said second and third patches, respectively;
means for launching radio frequency energy; and
means for ensuring maximum radiation at antenna boresight and suppressing cross-polarization levels.
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19. A microstrip antenna, comprising:
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a plurality of patches of at least two different widths, each patch among said plurality of patches being connected to an adjacent patch at at least two junctions;
a first patch among said plurality of patches disposed between opposing edges of a second patch and a third patch, said first patch having a narrower width than said second and third patches so that respective junctions formed between the first and second patch, and the first and third patch define discontinuities in width therebetween;
a coaxial feed disposed in said first patch to launch radio frequency energy, a feed point in said first patch being provided at a predetermined location so as to match an input impedance of the microstrip antenna to the coaxial feed; and
wherein said respective junctions formed between the first and second patch, and the first and third patch are symmetrically disposed about the first patch. - View Dependent Claims (20, 21)
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22. A method for reducing a size of a microstrip antenna, comprising the steps of:
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disposing a first patch of predetermined width at a first location;
joining said first patch to a second patch at at least two junctions, said second patch having narrower second width than the predetermined width of said first patch;
connecting a third patch to said second patch at at least two junctions, said third patch having a greater width than the narrower second width;
providing a feed in said second patch at a predetermined location so as to match input impedance of the antenna to the feed; and
symmetrically placing said at least two junctions about said second patch so as to ensure maximum radiation at antenna boresight and to suppress cross-polarization levels, wherein said second patch is located between opposing edges of said first and third patches. - View Dependent Claims (23, 24, 25, 26, 27)
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28. The method of 27, wherein said feed is located on said common axis and is not located at the center point of said second patch.
Specification