US5311202A
Expired / Lapsed
US
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Frequency-selective surface structure having H-shaped slots
Assignee: Airbus Defence and Space GmbH
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Filing: 1992-06-03
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Granted: 1994-05-10
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Expires: 2012-06-03
Abstract
Abstract A frequency-selective surface structure for narrow-band filtering of electromagnetic waves, comprising a fully wave-reflective surface perforated by H-shaped slot elements each consisting of end limiting bars and a connecting bar extending transversely with respect to the limiting bars. The end limiting bars of the individual slot elements each have essentially the same length as the connecting bar and have a bar length of approximately one fourth of the operating wave length.
Inventors
- 👤 Reinhard Popp
- 👤 Lothar Heichele
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 15:05
CPC Classifications
H; H01; H01Q; H01Q15/00; H01Q15/0006; H01Q15/0013; H01Q15/0026
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
85 words
A frequency-selective surface structure for the narrow-band filtering of electromagnetic waves, comprising a fully wave-reflective surface perforated by H-shaped slot elements, each H-shaped slot element being defined by parallel end limiting slots and a connecting slot extending transversely to and connected with the limiting slots, wherein each of the end limit slots of the slot elements has a length substantially equal to a length of the corresponding connecting slot, each said length being approximately one fourth of a wave length of a desired operating frequency.
Claim 2
Dependent Claim
85 words
A frequency-selective surface structure for the narrow-band filtering of electromagnetic waves, comprising a fully wave-reflective surface perforated by H-shaped slot elements, each H-shaped slot element being defined by parallel end limiting slots and a connecting slot extending transversely to and connected with the limiting slots, wherein each of the end limit slots of the slot elements has a length substantially equal to a length of the corresponding connecting slot, each said length being approximately one fourth of a wave length of a desired operating frequency.
Claim 3
Dependent Claim
38 words
A surface structure according to claim 1, wherein said slot elements are arranged in an array of adjacent slot elements, with each such slot element being oriented substantially at a right angle relative to slot elements adjacent thereto.
Claim 4
Dependent Claim
71 words
A surface structure according to claim 2, wherein said frequency selective surface comprises adjacent layers, including two outer cover layers defining said fully wave reflective surface, with each outer cover layer being perforated by said H-shaped slot elements, and an intermediate layer arranged between said outer cover layers, said intermediate layer comprising a low-loss dielectric material and having an electric layer thickness which corresponds to one fourth of said wave length.
Claim 5
Dependent Claim
37 words
A surface structure according to claim 2, wherein the slot elements are separated from each other in said array by a respective center distance of approximately one third of a wave length of a desired operating frequency.
Claim 6
Dependent Claim
31 words
A surface structure according to claim 4, wherein each of the connecting bars has a slot width that is twice as large as a slot width of the corresponding limiting bars.
Claim 7
Dependent Claim
71 words
A surface structure according to claim 5, wherein said frequency selective surface comprises adjacent layers, including two outer cover layers defining said fully wave reflective surface, with each outer cover layer being perforated by said H-shaped slot elements, and an intermediate layer arranged between said outer cover layers, said intermediate layer comprising a low-loss dielectric material and having an electric layer thickness which corresponds to one fourth of said wave length.
Claim 8
Dependent Claim
25 words
A surface structure according to claim 6, wherein the H-shaped slot elements are aligned in registration with one another in the two outer cover layers.
Claim 9
Dependent Claim
71 words
A surface structure according to claim 4, wherein said frequency selective surface comprises adjacent layers, including two outer cover layers defining said fully wave reflective surface, with each outer cover layer being perforated by said H-shaped slot elements, and an intermediate layer arranged between said outer cover layers, said intermediate layer comprising a low-loss dielectric material and having an electric layer thickness which corresponds to one fourth of said wave length.
Claim 10
Dependent Claim
31 words
A surface structure according to claim 2, wherein each of the connecting bars has a slot width that is twice as large as a slot width of the corresponding limiting bars.
Claim 11
Dependent Claim
71 words
A surface structure according to claim 9, wherein said frequency selective surface comprises adjacent layers, including two outer cover layers defining said fully wave reflective surface, with each outer cover layer being perforated by said H-shaped slot elements, and an intermediate layer arranged between said outer cover layers, said intermediate layer comprising a low-loss dielectric material and having an electric layer thickness which corresponds to one fourth of said wave length.
Claim 12
Dependent Claim
31 words
A surface structure according to claim 1, wherein each of the connecting bars has a slot width that is twice as large as a slot width of the corresponding limiting bars.
Claim 13
Dependent Claim
71 words
A surface structure according to claim 11, wherein said frequency selective surface comprises adjacent layers, including two outer cover layers defining said fully wave reflective surface, with each outer cover layer being perforated by said H-shaped slot elements, and an intermediate layer arranged between said outer cover layers, said intermediate layer comprising a low-loss dielectric material and having an electric layer thickness which corresponds to one fourth of said wave length.
Claim 14
Dependent Claim
37 words
A surface structure according to claim 1, wherein the slot elements are separated from each other in said array by a respective center distance of approximately one third of a wave length of a desired operating frequency.
Claim 15
Dependent Claim
31 words
A surface structure according to claim 13, wherein each of the connecting bars has a slot width that is twice as large as a slot width of the corresponding limiting bars.
Claim 16
Dependent Claim
71 words
A surface structure according to claim 14, wherein said frequency selective surface comprises adjacent layers, including two outer cover layers defining said fully wave reflective surface, with each outer cover layer being perforated by said H-shaped slot elements, and an intermediate layer arranged between said outer cover layers, said intermediate layer comprising a low-loss dielectric material and having an electric layer thickness which corresponds to one fourth of said wave length.
Claim 17
Dependent Claim
71 words
A surface structure according to claim 13, wherein said frequency selective surface comprises adjacent layers, including two outer cover layers defining said fully wave reflective surface, with each outer cover layer being perforated by said H-shaped slot elements, and an intermediate layer arranged between said outer cover layers, said intermediate layer comprising a low-loss dielectric material and having an electric layer thickness which corresponds to one fourth of said wave length.
Claim 18
Dependent Claim
71 words
A surface structure according to claim 1, wherein said frequency selective surface comprises adjacent layers, including two outer cover layers defining said fully wave reflective surface, with each outer cover layer being perforated by said H-shaped slot elements, and an intermediate layer arranged between said outer cover layers, said intermediate layer comprising a low-loss dielectric material and having an electric layer thickness which corresponds to one fourth of said wave length.
Claim 19
Dependent Claim
25 words
A surface structure according to claim 17, wherein the H-shaped slot elements are aligned in registration with one another in the two outer cover layers.
Claim 20
Dependent Claim
18 words
A surface structure according to claim 17, wherein said outer cover layers are comprised of a conductive material.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-05-09 | 1997-11-08 | 1998-05-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-05-09 | 2001-11-08 | 2002-05-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-05-09 | 2005-11-08 | 2006-05-10 | $7700.00 | Window Closed / Lapsed |