Dual band multimode coaxial tracking feed
First Claim
1. An electromagnetic wave interface device comprising:
- a generally cylindrically nested waveguide structure including an inner section of generally longitudinal waveguide extending along an axis from a first end to a distal end thereof, and an outer stepped section of coaxial waveguide surrounding said inner section of generally longitudinal waveguide along said axis, said outer stepped section having an endwall axially displaced from the first end of the inner section of generally longitudinal waveguide toward the distal end thereof, said inner section of generally longitudinal waveguide having axially displaced sidewalls between the endwall of the outer stepped section of coaxial waveguide and the first end of the inner section of generally longitudinal waveguide;
a first electromagnetic wave transducer forming a first port of said inner section of generally longitudinal waveguide to interface therewith first signals having a frequency in a first frequency band;
a second electromagnetic wave transducer forming a second port of said inner section of generally longitudinal waveguide to interface therewith second signals having a frequency in said first frequency band, and mutually isolated from said first signals;
said first and second ports being located at the axially displaced sidewalls of the inner section of generally longitudinal waveguide;
a third electromagnetic wave transducer coupled to a first side portion of said outer stepped section of coaxial waveguide and forming a third port to interface said outer stepped section of coaxial waveguide with third signals having a frequency in a second frequency band spectrally spaced apart from said first frequency band; and
a fourth electromagnetic wave transducer coupled to a second side portion of said outer stepped section of coaxial waveguide, spatially separated from said first side portion thereof and forming a fourth port to interface said outer stepped section of coaxial waveguide with fourth signals having a frequency in said second frequency band, and in a manner that provides mutual isolation between said third and fourth signals.
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Accused Products
Abstract
A dual band multimode coaxial antenna feed has an inner section of longitudinal hollow waveguide having first and second orthogonal mode transducers that interface first and second orthogonally polarized cylindrical waveguide TE11 mode signals lying in a first upper (e.g., Ka) frequency band. An outer coaxial waveguide section has a Potter horn surrounding the inner waveguide section, which terminates at a polyrod. The outer section includes third and fourth orthogonal mode transducers that interface orthogonally polarized coaxial waveguide TE11 mode signals lying in a second lower (e.g., X) frequency band. A tracking port coupled to the outer coaxial waveguide section provides an output representative of the difference pattern of the radiation profile produced by transverse electromagnetic TEM mode signals generated and propagating in the outer coaxial waveguide. A mode suppressor in the outer waveguide section adjacent its two orthogonal mode transducers locally suppresses TEM signals in their vicinity. A broadband compensated polarizer is installed in the inner waveguide section operating in the high band, and a broadband coaxial compensated polarizer is installed in the outer coaxial waveguide section operating in the low band.
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Citations
19 Claims
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1. An electromagnetic wave interface device comprising:
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a generally cylindrically nested waveguide structure including an inner section of generally longitudinal waveguide extending along an axis from a first end to a distal end thereof, and an outer stepped section of coaxial waveguide surrounding said inner section of generally longitudinal waveguide along said axis, said outer stepped section having an endwall axially displaced from the first end of the inner section of generally longitudinal waveguide toward the distal end thereof, said inner section of generally longitudinal waveguide having axially displaced sidewalls between the endwall of the outer stepped section of coaxial waveguide and the first end of the inner section of generally longitudinal waveguide;
a first electromagnetic wave transducer forming a first port of said inner section of generally longitudinal waveguide to interface therewith first signals having a frequency in a first frequency band;
a second electromagnetic wave transducer forming a second port of said inner section of generally longitudinal waveguide to interface therewith second signals having a frequency in said first frequency band, and mutually isolated from said first signals;
said first and second ports being located at the axially displaced sidewalls of the inner section of generally longitudinal waveguide;
a third electromagnetic wave transducer coupled to a first side portion of said outer stepped section of coaxial waveguide and forming a third port to interface said outer stepped section of coaxial waveguide with third signals having a frequency in a second frequency band spectrally spaced apart from said first frequency band; and
a fourth electromagnetic wave transducer coupled to a second side portion of said outer stepped section of coaxial waveguide, spatially separated from said first side portion thereof and forming a fourth port to interface said outer stepped section of coaxial waveguide with fourth signals having a frequency in said second frequency band, and in a manner that provides mutual isolation between said third and fourth signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A dual band multimode coaxial feed structure for a reflector antenna comprising:
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an inner section of generally longitudinal hollow waveguide extending along an axis from a first end to a distal end thereof, and having first and second orthomode electromagnetic wave transducers respectively forming first and second radial ports of said dual band multimode coaxial feed structure to interface therewith first and second (TE11 mode) signals having a frequency in a first frequency band;
an outer stepped section of coaxial waveguide surrounding said inner section of generally longitudinal waveguide along said axis, and having a third radial port that includes a third orthomode transducer to interface third (TE11 mode) signals having a frequency in a second frequency band lower than said first frequency band, and having a fourth radial port that includes a fourth orthomode transducer to interface fourth (TE11 mode) signals having a frequency in said second frequency band, while providing mutual electromagnetic isolation between said third and fourth (TE11 mode) signals, said outer stepped section having an endwall axially displaced from the first end of the inner section of generally longitudinal hollow waveguide toward the distal end thereof; and
a tracking port to provide an output representative of transverse electromagnetic mode (TEM) signals generated and propagating in said outer stepped section of coaxial waveguide;
said inner section of generally longitudinal hollow waveguide having axially displaced sidewalls between the endwall of the outer stepped section of coaxial waveguide and the first end of the inner section of generally longitudinal waveguide, and said first and second ports being located at the axially displaced sidewalls of the inner section of generally longitudinal waveguide. - View Dependent Claims (12, 13, 14, 15, 16)
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17. A method of interfacing electromagnetic energy with an antenna reflector comprising the steps of:
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(a) providing a dual band multimode electromagnetic energy coupling interface that includes an inner section of generally longitudinal hollow waveguide extending along an axis from a first end to a distal end thereof, and having a first port coupled to a first electromagnetic wave transducer to interface first signals having a frequency in a first frequency band, and a second port coupled to a second electromagnetic wave transducer to interface second signals having a frequency in said first frequency band and being orthogonally polarized relative to said first signals, and an outer stepped section of coaxial waveguide surrounding said inner section of generally longitudinal waveguide along said axis to form a coaxial waveguide structure therewith, and having a third port radially coupled to a third electromagnetic wave transducer to interface third signals having a frequency in a second frequency band spectrally spaced apart from said first frequency band, and a fourth port radially coupled to a fourth electromagnetic wave transducer to interface fourth signals having a frequency in said second frequency band and being orthogonally polarized with said third signals, said outer stepped section having an endwall axially displaced from the first end of the inner section of generally longitudinal hollow waveguide toward the distal end thereof, said inner section of generally longitudinal hollow waveguide having axially displaced sidewalls between the endwall of the outer stepped section of coaxial waveguide and the first end of the inner section of generally longitudinal waveguide, and said first and second ports being located at the axially displaced sidewalls of the inner section of generally longitudinal waveguide; and
(b) operating said dual band multimode electromagnetic energy coupling interface to perform at least one of the following actions;
transmitting two orthogonally polarized signals in said first frequency band, receiving two orthogonally polarized signals in said first frequency band, transmitting two orthogonally polarized signals in said second frequency band, and receiving two orthogonally polarized signals in said second frequency band. - View Dependent Claims (18, 19)
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Specification