US3662393A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multimode horn antenna
Assignee: Emerson Electric Co
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Filing: 1970-02-20
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Granted: 1972-05-09
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Expires: 1990-02-20
Abstract
Abstract A conical or pyramidal horn-radiator having small flare angle changes within the horn at cross-section dimensions much larger than the input waveguide, to excite higher order modes which control the E-plane aperture distribution and produce a tapered aperture field in the E-plane. Equal E- and H-plane beamwidths are thereby obtained. The horn has particular use as a feed for a parabolic reflector, such as a Cassegrain antenna. The flare angle changes are used for pattern improvement in a first frequency band, and separate means are provided for pattern improvement in a second band.
Inventors
- 👤 Seymour B Cohn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:03
CPC Classifications
H; H01; H01Q; H01Q13/00; H01Q13/02; H01Q13/025
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
300 words
Means for transmitting or receiving a beam of electromagnetic wave energy comprising: an input transmission line having an output end, said transmission line comprising at least one waveguide proportioned to propagate electromagnetic wave energy in at least a first frequency band in a dominant mode, and a horn of regular cross-section, said horn comprising: a first flared section having a positive flare angle and having an input end and an output end, said input end of said first flared section communicating with said output end of said input transmission line, said output end of said first flared section having a large cross-sectional dimension at least three times the cross-sectional dimension of the output end of the waveguide; an output flared section having a positive flare angle and having an input end and an output end, said output end of said output flared section comprising an aperture opening into free space; and connecting means for connecting said output end of said first flared section with said input end of said output flared section, said connecting means forming a plurality of small angle changes within said horn including at least a first flare angle change with said first flared section and an output flare angle change with said output flared section, said flare angle changes being proportioned to convert a desired portion of electromagnetic wave energy transmitted from said input transmission line through said horn in said first frequency band, from said dominant mode to at least one higher mode, and said sections and said connecting means being proportioned such that in transmitting from said input transmission line through said horn in said first frequency band, said higher mode wave energy produced at said flare angle changes causes the horn to suppress sidelobes and to produce approximately equal E- and Hplane beamwidths.
Claim 2
Dependent Claim
300 words
Means for transmitting or receiving a beam of electromagnetic wave energy comprising: an input transmission line having an output end, said transmission line comprising at least one waveguide proportioned to propagate electromagnetic wave energy in at least a first frequency band in a dominant mode, and a horn of regular cross-section, said horn comprising: a first flared section having a positive flare angle and having an input end and an output end, said input end of said first flared section communicating with said output end of said input transmission line, said output end of said first flared section having a large cross-sectional dimension at least three times the cross-sectional dimension of the output end of the waveguide; an output flared section having a positive flare angle and having an input end and an output end, said output end of said output flared section comprising an aperture opening into free space; and connecting means for connecting said output end of said first flared section with said input end of said output flared section, said connecting means forming a plurality of small angle changes within said horn including at least a first flare angle change with said first flared section and an output flare angle change with said output flared section, said flare angle changes being proportioned to convert a desired portion of electromagnetic wave energy transmitted from said input transmission line through said horn in said first frequency band, from said dominant mode to at least one higher mode, and said sections and said connecting means being proportioned such that in transmitting from said input transmission line through said horn in said first frequency band, said higher mode wave energy produced at said flare angle changes causes the horn to suppress sidelobes and to produce approximately equal E- and Hplane beamwidths.
Claim 3
Dependent Claim
21 words
The means of claim 1 wherein said input transmission line is a waveguide of the same regular cross-section as said horn.
Claim 4
Dependent Claim
24 words
The means of claim 1 wherein said horn is square in cross-section, said dominant mode is TE10, and said one higher mode comprises TE/TM12.
Claim 5
Dependent Claim
113 words
The means of claim 1 wherein said connecting means comprises a second flared section connected to said first flared section and a third section connected to said second flared section, the flare angle of said second flared section being approximately half the sum of the flare angle of said first flared section and the flare angle of the third section, said second flared section being so proportioned that the flare angle change between said second flared section and said third section cancels substantially all of a mode, different from said dominant mode and said one higher mode, produced at the flare angle change between said first flared section and said second flared section.
Claim 6
Dependent Claim
31 words
The means of claim 3 wherein said portion of TE/TM12 mode produced at said flare angle changes yields a ratio of TE/TM12 to TE10 of between about 0.65 and about 0.84.
Claim 7
Dependent Claim
170 words
Means for transmitting and receiving electromagnetic wave energy comprising: a waveguide part of uniform, regular cross-section, said waveguide part being proportioned to support a first mode in a transmit frequency band and in a receive frequency band, and to support a second, higher, mode in one only of said frequency bands, a horn part of the same regular cross-section as said waveguide part connected to said waveguide part, means in said waveguide part for converting a desired portion of said first mode of said one of said frequency bands to said higher mode, said means in said waveguide part having substantially no effect on the other of said frequency bands, and means in said horn part for converting a desired portion of said first mode of the other of said frequency bands to a second, higher, mode, said means in said horn part comprising a plurality of small flare angle changes at large cross-sectional dimensions of said horn part at least three times the cross-sectional dimension of the waveguide part.
Claim 8
Dependent Claim
170 words
Means for transmitting and receiving electromagnetic wave energy comprising: a waveguide part of uniform, regular cross-section, said waveguide part being proportioned to support a first mode in a transmit frequency band and in a receive frequency band, and to support a second, higher, mode in one only of said frequency bands, a horn part of the same regular cross-section as said waveguide part connected to said waveguide part, means in said waveguide part for converting a desired portion of said first mode of said one of said frequency bands to said higher mode, said means in said waveguide part having substantially no effect on the other of said frequency bands, and means in said horn part for converting a desired portion of said first mode of the other of said frequency bands to a second, higher, mode, said means in said horn part comprising a plurality of small flare angle changes at large cross-sectional dimensions of said horn part at least three times the cross-sectional dimension of the waveguide part.
Claim 9
Dependent Claim
210 words
Antenna means for transmitting and receiving electromagnetic wave energy comprising: an input transmission line part having an output end, said transmission line comprising at least one waveguide proportioned to propagate electromagnetic wave energy in a dominant mode in at least a transmit frequency band and in a receive frequency band, and a horn part connected to said waveguide part at one end and having an aperture at its other end, first means in said horn part for converting a desired portion of said first mode of one of said frequency bands to a second, higher, mode, said first means comprising at least one small flare angle change at a large cross-sectional dimension of said horn part at least three times the cross-sectional dimension of the output end of the waveguide, said horn part being proportioned to produce a desired phase relationship between said first and second modes at said aperture, and second means at the output end of the transmission line part for converting a portion of said first mode of the other of said frequency bands to said higher mode, said second means being located at a cross-sectional dimension of said antenna means substantially smaller than said first means and having substantially no effect on said one frequency band.
Claim 10
Dependent Claim
210 words
Antenna means for transmitting and receiving electromagnetic wave energy comprising: an input transmission line part having an output end, said transmission line comprising at least one waveguide proportioned to propagate electromagnetic wave energy in a dominant mode in at least a transmit frequency band and in a receive frequency band, and a horn part connected to said waveguide part at one end and having an aperture at its other end, first means in said horn part for converting a desired portion of said first mode of one of said frequency bands to a second, higher, mode, said first means comprising at least one small flare angle change at a large cross-sectional dimension of said horn part at least three times the cross-sectional dimension of the output end of the waveguide, said horn part being proportioned to produce a desired phase relationship between said first and second modes at said aperture, and second means at the output end of the transmission line part for converting a portion of said first mode of the other of said frequency bands to said higher mode, said second means being located at a cross-sectional dimension of said antenna means substantially smaller than said first means and having substantially no effect on said one frequency band.
Claim 11
Dependent Claim
134 words
Means for transmitting or receiving a beam of electromagnetic wave energy comprising: an input transmission line comprising at least one waveguide proportioned to propagate electromagnetic wave energy in at least a first frequency band in a dominant mode, a horn part connected to said transmission line, said horn part having at least four axial flare sections of different flaring angles, one of said flare sections converting a desired portion of said dominant mode to a higher order mode and comprising a small flare angle change in said horn at a large cross-sectional dimension of said horn part at least three times the cross-sectional dimension of the input waveguide, said horn part being proportioned to produce a desired phase relationship between said dominant mode and said higher order mode induced by said flare angle change.
Claim 12
Dependent Claim
134 words
Means for transmitting or receiving a beam of electromagnetic wave energy comprising: an input transmission line comprising at least one waveguide proportioned to propagate electromagnetic wave energy in at least a first frequency band in a dominant mode, a horn part connected to said transmission line, said horn part having at least four axial flare sections of different flaring angles, one of said flare sections converting a desired portion of said dominant mode to a higher order mode and comprising a small flare angle change in said horn at a large cross-sectional dimension of said horn part at least three times the cross-sectional dimension of the input waveguide, said horn part being proportioned to produce a desired phase relationship between said dominant mode and said higher order mode induced by said flare angle change.
Claim 13
Dependent Claim
52 words
The means of claim 8 wherein said small flare angle change induces said first-mentioned higher order mode and a second higher order mode, and including means, comprising at least a second small flare angle change, proportioned and spaced from said first-mentioned small flare angle change to cancel said second higher order mode.
Claim 14
Dependent Claim
178 words
Means for transmitting or receiving a beam of electromagnetic wave energy comprising: an input transmission line having an output end, said transmission line being proportioned to propagate electromagnetic wave energy in at least a first frequency band in a dominant mode, and a horn of regular cross-section, said horn comprising a first section; a second, flared, section connected to said first section to form a first flare angle change at a first cross-sectional dimension of said horn; and a third section connected to said second section to form a second flare angle change at a second cross-sectional dimension of said horn, the product of said first flare angle change times said first cross-sectional dimension being approximately equal to the product of the second flare angle change times said second cross-sectional dimension, said first flare change inducing a first higher order mode and a second higher order mode in said first frequency band, said second section being so proportioned that said second flare angle change cancels substantially all of the second higher order mode in said first frequency band.
Claim 15
Dependent Claim
178 words
Means for transmitting or receiving a beam of electromagnetic wave energy comprising: an input transmission line having an output end, said transmission line being proportioned to propagate electromagnetic wave energy in at least a first frequency band in a dominant mode, and a horn of regular cross-section, said horn comprising a first section; a second, flared, section connected to said first section to form a first flare angle change at a first cross-sectional dimension of said horn; and a third section connected to said second section to form a second flare angle change at a second cross-sectional dimension of said horn, the product of said first flare angle change times said first cross-sectional dimension being approximately equal to the product of the second flare angle change times said second cross-sectional dimension, said first flare change inducing a first higher order mode and a second higher order mode in said first frequency band, said second section being so proportioned that said second flare angle change cancels substantially all of the second higher order mode in said first frequency band.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-05-09 | 1975-11-08 | 1976-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-09 | 1979-11-08 | 1980-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-09 | 1983-11-08 | 1984-05-09 | $7700.00 | Window Closed / Lapsed |