US3733606A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Camouflaging means for preventing or obstructing detection by radar reconnaissance
Assignee: Barracudaverken AB
•
Filing: 1971-04-06
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Granted: 1973-05-15
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Expires: 1991-04-06
Abstract
Abstract Camouflage means for minimizing detection of objects by radar reconnaissance consisting of a multi-layered material both absorbing and reflecting radar signals and wherein at least one layer is a thin inhomogeneous electrically conductive film having a surface resistivity such as to establish reflection for a portion of the incident radar power. The conductive film may take the form of metallic grid which may be regular or irregular, metal or metallized fibers and fibrils, flakes, or a layer of colloidal, conductive particles.
Inventors
- 👤 S Johansson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:48
CPC Classifications
F; F41; F41H; F41H3/00; F41H3/02; H; H01; H01Q; H01Q17/00; H01Q17/002; Y; Y10; Y10S; Y10S428/00; Y10S428/919; Y10T; Y10T428/00; Y10T428/30; Y10T442/00; Y10T442/10; Y10T442/102; Y10T442/109; Y10T442/126
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
20 words
Camouflage means as defined in claim 1 wherein the surface resistivity of said electrically conductive film is about 220 ohms.
Claim 2
Dependent Claim
20 words
Camouflage means as defined in claim 1 wherein the surface resistivity of said electrically conductive film is about 640 ohms.
Claim 3
Dependent Claim
51 words
Camouflage means as defined in claim 1 wherein said electrically conductive film is an extremely fine metal film exhibiting pores and apertures to render the effect surface resistivity of the layer by one or more orders higher than the surface resistivity of a homogeneous layer of the same material and thickness.
Claim 4
Dependent Claim
30 words
Camouflage means as defined in claim 4 wherein substantially all of said apertures have dimensions which are negligible with respect to one quarter of the wavelength of the radar signals.
Claim 5
Dependent Claim
17 words
Camouflage means as defined in claim 1 wherein said electrically conductive film is a conductive metallic grid.
Claim 6
Dependent Claim
49 words
Camouflage means as defined in claim 6 wherein said conductive metallic grid is irregular such that the meshes forming the apertures therein differ in form and size, the plurality of meshes having dimensions which are not negligible with respect to one quarter of the wavelength of the radar signals.
Claim 7
Dependent Claim
39 words
Camouflage means as defined in claim 6 wherein said conductive metallic grid is substantially regular and the meshes forming the apertures therein have dimensions which are negligible with respect to one quarter of the wavelength of the radar signals.
Claim 8
Dependent Claim
43 words
Camouflage means as defined in claim 1 wherein said electrically conductive film is approximately uniform and is composed of finely distributed conductive particles having the character of discrete colloidal particles which have a relatively low resistivity of the order of that of graphite.
Claim 9
Dependent Claim
47 words
Camouflage means as defined in claim 1 wherein said electrically conductive film comprises short, non-spun, unwoven fibers having a metallic surface and wherein the majority of the fibers has a length which is not negligible with respect to one quarter of the wavelength of the radar signals.
Claim 10
Dependent Claim
24 words
Camouflage means as defined in claim 10 wherein said fibers consist of a metal and have a thickness of approximately less than 15 microns.
Claim 11
Dependent Claim
21 words
Camouflage means as defined in claim 10 wherein said fibers consist of monofilous synthetic fibers covered with an electrically conductive film.
Claim 12
Dependent Claim
63 words
Camouflage means as defined in claim 1 wherein said flexible material is constituted by a flat, substantially two-dimensional flexible sheet having a plurality of cuts therein of such length and distribution over the sheet that when the sheet is subjected to a pull, the extended sheet becomes three-dimensional, the length of each cut exceeding one quarter of the wavelength of the radar signals.
Claim 13
Dependent Claim
75 words
Camouflage means as defined in claim 13 wherein the cuts in said sheet are curved and interlocked with each other such that the ends of the cuts terminate within the fields defined by adjacent substantially oppositely disposed curved cuts such that when the cut out areas extend beyond the plane of the sheet, said areas have their greatest dimension exceeding a half wavelength of the radar signals which have a frequency higher than 2000 MHz.
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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) | 1976-05-14 | 1976-11-13 | 1977-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-14 | 1980-11-13 | 1981-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-14 | 1984-11-13 | 1985-05-15 | $7700.00 | Window Closed / Lapsed |