Multi-band horn antenna using frequency selective surfaces
First Claim
1. A waveguide comprising:
- at least one outer surface defining a waveguide cavity; and
at least one inner surface positioned within said waveguide cavity, wherein said inner surface comprises a frequency selective surface (FSS) having a plurality of frequency selective surface elements coupled to at least one substrate, said substrate defining a first propagation medium such that an RF signal having a first wavelength in said first propagation medium can pass through said frequency selective surface;
wherein said frequency selective surface is coupled to a second propagation medium such that in said second propagation medium said RF signal has a second wavelength which is at least twice as long as a physical distance between centers of adjacent ones of said frequency selective surface elements;
wherein said substrate comprises at least one material selected from the group consisting of a meta-material and a liquid crystal polymer.
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Abstract
A waveguide (100) including at least one outer surface (105, 110, 115, 120) defining a waveguide cavity (140) and at least one inner surface (130, 135) positioned within the waveguide cavity (140). The inner surface (130, 135) includes a frequency selective surface (FSS) having a plurality of FSS elements (145) coupled to at least one substrate. The substrate defines a first propagation medium such that an RF signal having a first wavelength in the first propagation medium can pass through the FSS (130, 135). The FSS (130, 135) is coupled to a second propagation medium such that in the second propagation medium the RF signal has a second wavelength which is at least twice as long as a physical distance between centers of adjacent FSS elements (145). The second wavelength can be different than the first wavelength.
238 Citations
21 Claims
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1. A waveguide comprising:
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at least one outer surface defining a waveguide cavity; and
at least one inner surface positioned within said waveguide cavity, wherein said inner surface comprises a frequency selective surface (FSS) having a plurality of frequency selective surface elements coupled to at least one substrate, said substrate defining a first propagation medium such that an RF signal having a first wavelength in said first propagation medium can pass through said frequency selective surface;
wherein said frequency selective surface is coupled to a second propagation medium such that in said second propagation medium said RF signal has a second wavelength which is at least twice as long as a physical distance between centers of adjacent ones of said frequency selective surface elements;
wherein said substrate comprises at least one material selected from the group consisting of a meta-material and a liquid crystal polymer. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An antenna for microwave radiation comprising:
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a first horn; and
at least a second horn positioned within said first horn, said second horn comprising at least one frequency selective surface having a plurality of frequency selective surface elements coupled to at least one substrate, said substrate defining a first propagation medium such that an RF signal having a first wavelength in said first propagation medium can pass through said frequency selective surface;
wherein said frequency selective surface is coupled to a second propagation medium such that in said second propagation medium said RF signal has a second wavelength which is at least twice as long as a physical distance between centers of adjacent ones of said frequency selective surface elements. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. A waveguide horn antenna comprising,
a tapered hollow metallic conductor; - and
a frequency selective surface comprising a substrate and an array of elements defining at least one wall of said horn, said frequency selective surface positioned for confining and guiding a propagating electromagnetic wave;
said substrate having at least one of a permeability and a permittivity greater than about three. - View Dependent Claims (17)
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18. A method for improving performance in a horn antenna comprising the steps of:
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forming at least one wall of said horn antenna of a frequency selective surface; and
selectively reducing at least one grating lobe of said antenna by increasing at least one of a permittivity and a permeability of a substrate comprising said frequency selective surface to a value greater than three. - View Dependent Claims (19, 20)
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21. A waveguide comprising:
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at least one outer surface defining a waveguide cavity; and
at least one inner surface positioned within said waveguide cavity arranged parallel to said outer surface, said inner surface comprising a frequency selective surface (FSS) having a plurality of frequency selective surface elements coupled to at least one substrate;
wherein an RF signal having a first wavelength passes through said frequency selective surface and is incident on said at least one outer surface, and an RF signal having a second wavelength does not pass through said inner surface, wherein said inner surface defines a wall of a second waveguide structure.
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Specification