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US3877031A
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Method and apparatus for suppressing grating lobes in an electronically scanned antenna array
Assignee: United States Department of the Air Force
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Filing: 1973-06-29
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Granted: 1975-04-08
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Expires: 1993-06-29
Abstract
Abstract Grating lobe suppression in an electronically scanned antenna array is realized by adding odd mode power to the fundamental even mode power that normally drives each radiating element of the array. The odd mode power is maintained .+-. 90.degree. out of phase with the even mode power at each radiating element aperture. The ratio of even mode power to odd mode power is varied as a function of main beam displacement from broadside. One class of circuit for automatically accomplishing the required functions utilize waveguide power dividers and phase shifters. An alternative embodiment comprehends the use of passive, reciprocal linear circuitry to perform the power division. In some circuits the phase difference between adjacent radiating elements is used to derive odd and even mode signals.
Inventors
- 👤 Robert J Mailloux
- 👤 Allan C Schell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 19:51
CPC Classifications
H; H01; H01Q; H01Q25/00; H01Q25/04
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
92 words
The method of suppressing grating lobes in an electronically scanned antenna array comprising the steps of dividing the fundamental even mode power for each radiating element of the array into two power sources for each plane of scan converting the power of one power source for each plane of scan to odd mode power, varying the ratio of even mode power to odd mode power as a function of beam position, and maintaining a 90.degree. out of phase relationship between even mode power and odd mode power at each radiating element aperture.
Claim 2
Independent Claim
92 words
The method of suppressing grating lobes in an electronically scanned antenna array comprising the steps of dividing the fundamental even mode power for each radiating element of the array into two power sources for each plane of scan converting the power of one power source for each plane of scan to odd mode power, varying the ratio of even mode power to odd mode power as a function of beam position, and maintaining a 90.degree. out of phase relationship between even mode power and odd mode power at each radiating element aperture.
Claim 3
Dependent Claim
146 words
In an antenna system having an array of radiating elements, circuits for feeding fundamental mode electromagnetic wave power to each radiating element, and means for electronically scanning the main beam radiating from the array of radiating elements, the improvement comprising grating lobe suppression apparatus, said grating lobe suppression apparatus including means for dividing the fundamental mode power feed circuit for each radiating element into two feed channels for each plane of scan, means adapted to feed each radiating element through said feed channels to provide one even mode and one odd mode power source for each plane of scan, means associated with each radiating element for varying the ratio of even mode power to odd mode power as a function of main beam position, and means for providing, at each radiating element aperture, a 90.degree. out of phase relationship between odd mode and even mode power.
Claim 4
Dependent Claim
146 words
In an antenna system having an array of radiating elements, circuits for feeding fundamental mode electromagnetic wave power to each radiating element, and means for electronically scanning the main beam radiating from the array of radiating elements, the improvement comprising grating lobe suppression apparatus, said grating lobe suppression apparatus including means for dividing the fundamental mode power feed circuit for each radiating element into two feed channels for each plane of scan, means adapted to feed each radiating element through said feed channels to provide one even mode and one odd mode power source for each plane of scan, means associated with each radiating element for varying the ratio of even mode power to odd mode power as a function of main beam position, and means for providing, at each radiating element aperture, a 90.degree. out of phase relationship between odd mode and even mode power.
Claim 5
Dependent Claim
43 words
Grating lobe suppression apparatus as defined in claim 2 wherein each said means for varying the ratio of even mode power to odd mode power effects and maintains a null in its associated radiation element radiation pattern at one principal grating lobe position.
Claim 6
Dependent Claim
68 words
Grating lobe suppression apparatus as defined in claim 3 wherein said means for providing 90.degree. out of phase relationship between odd mode and even mode power effects, for each plane of scan, a +90.degree. out of phase relationship when the main beam is scanned to one side of broadside and a -90.degree. out of phase relationship when the main beam is scanned to the opposite side of broadside.
Claim 7
Dependent Claim
34 words
Grating lobe suppression apparatus as defined in claim 4 wherein said array of radiating elements is a rectangular array of rectangular horn antennas and said fundamental mode electromagnetic wave power is LSE.sub.10 mode power.
References Cited (Backward Citations)
US3392395A
Cited
US3423756A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-04-07 | 1978-10-07 | 1979-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-07 | 1982-10-07 | 1983-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-07 | 1986-10-07 | 1987-04-08 | $7700.00 | Window Closed / Lapsed |