Patent US3568195A successfully refreshed from Google Patents.
US3568195A
Expired / Lapsed
US
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Electromagnetic wave attenuating device
Assignee: Individual
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Filing: 1959-11-23
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Granted: 1971-03-02
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Expires: 1979-11-23
Abstract
Abstract A radar wave absorber is disclosed which does not require a metal backing layer. The absorber operates according to interference principles, with a portion of the wave reflected from the absorber''s back layer interfering with the wave reflected from the surface layer. The backing material must exhibit a high relative dielectric constant, or a high relative magnetic permeability and dielectric loss tangent, or a high magnetic loss tangent, or a combination of these properties.
Inventors
- 👤 Ludwig Wesch
- 👤 Hans H Meinke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 11:13
CPC Classifications
H; H01; H01Q; H01Q17/00; H01Q17/004
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
77 words
An improved device for attenuating impinging radar waves by interference, consisting of the combination of an outer radar wave attenuating layer means having a surface reflecting one part of the impinging waves and a wave reflecting backing reflecting the other part of the impinging waves, which have penetrated into the layer means, said backing being a nonmetallic sheet having a relative dielectric constant of between 20 and 600, and a relative permeability of between 0.9 and 10.
Claim 2
Dependent Claim
77 words
An improved device for attenuating impinging radar waves by interference, consisting of the combination of an outer radar wave attenuating layer means having a surface reflecting one part of the impinging waves and a wave reflecting backing reflecting the other part of the impinging waves, which have penetrated into the layer means, said backing being a nonmetallic sheet having a relative dielectric constant of between 20 and 600, and a relative permeability of between 0.9 and 10.
Claim 3
Dependent Claim
26 words
The device of claim 1, wherein the relative dielectric constant of the nonmetallic backing is between 100 and 200, and the relative permeability is about 1.
Claim 4
Dependent Claim
27 words
The device of claim 1, wherein the nonmetallic backing consists of a dielectric binder material containing a particulate filler controlling the high frequency constant of the backing.
Claim 5
Dependent Claim
36 words
The device of claim 1, wherein the nonmetallic backing consists of a dielectric base material selected from the group consisting of concrete and cement containing a particulate filler controlling the high frequency constant of the backing.
Claim 6
Dependent Claim
40 words
The device of claim 1, wherein the nonmetallic backing consists of a dielectric base material containing a particulate filler selected from the group consisting of iron, ferrites, magnetites and mixtures thereof, having a grain size of 0.1 to 100 microns.
Claim 7
Dependent Claim
29 words
The device of claim 1, wherein the nonmetallic backing is composed essentially of a synthetic resin containing a particulate filler imparting a high high frequency loss to the backing.
Claim 8
Dependent Claim
13 words
The device of claim 6, wherein said synthetic resin is a synthetic rubber.
Claim 9
Dependent Claim
22 words
The device of claim 7, wherein said synthetic rubber is selected from the group consisting of butyl rubber and a butadiene-base rubber.
Claim 10
Dependent Claim
18 words
The device of claim 6, wherein at least the major portion of the particulate filler consists of graphite.
Claim 11
Dependent Claim
19 words
The device of claim 6, wherein at least the major portion of the particulate filler consists of carbon black.
Claim 12
Dependent Claim
21 words
The device of claim 6, wherein at least the major portion of the particulate filler consists of graphite and carbon black.
Claim 13
Dependent Claim
85 words
An improved device for attenuating impinging radar waves by interference, consisting of the combination of an outer radar wave attenuating layer means having a surface reflecting one part of the impinging waves and a wave reflecting backing reflecting the other part of the impinging waves, which have penetrated into the layer means, saId backing being a sheet composed essentially of polyisobutylene and a particulate filler of graphite and carbon black, the backing sheet having a thickness of the order or magnitude of a few millimeters.
Claim 14
Dependent Claim
85 words
An improved device for attenuating impinging radar waves by interference, consisting of the combination of an outer radar wave attenuating layer means having a surface reflecting one part of the impinging waves and a wave reflecting backing reflecting the other part of the impinging waves, which have penetrated into the layer means, saId backing being a sheet composed essentially of polyisobutylene and a particulate filler of graphite and carbon black, the backing sheet having a thickness of the order or magnitude of a few millimeters.
Claim 15
Dependent Claim
23 words
The device of claim 12, wherein the weight ratio of the polyisobutylene, graphite and carbon black is about 2 : 4 : 4.
Claim 16
Dependent Claim
105 words
An improved device for attenuating impinging radar waves by interference, consisting of the combination of an outer radar wave attenuating layer means having a surface reflecting one part of the impinging waves and a wave reflecting backing reflecting the other part of the impinging waves, which have penetrated into the layer means, said backing being a sheet composed essentially of a synthetic resin containing from about 30 percent to about 80 percent, by weight, of a particulate filler imparting a high high frequency loss to the backing sheet, at least a major portion of said filler consisting of a mixture of graphite and carbon black.
Claim 17
Dependent Claim
105 words
An improved device for attenuating impinging radar waves by interference, consisting of the combination of an outer radar wave attenuating layer means having a surface reflecting one part of the impinging waves and a wave reflecting backing reflecting the other part of the impinging waves, which have penetrated into the layer means, said backing being a sheet composed essentially of a synthetic resin containing from about 30 percent to about 80 percent, by weight, of a particulate filler imparting a high high frequency loss to the backing sheet, at least a major portion of said filler consisting of a mixture of graphite and carbon black.
Claim 18
Dependent Claim
21 words
The device of claim 14, wherein the filler includes a minor portion of at least one permeable high frequency iron powder.
Claim 19
Dependent Claim
69 words
An improved device for attenuating impinging radar waves by interference, consisting of the combination of an outer radar wave attenuating layer means having a surface reflecting one part of the impinging waves and a wave reflecting backing reflecting the other part of the impinging waves, which have penetrated into the layer means, said backing being a sheet composed essentially of a vulcanized butadiene acrylonitrile copolymer, graphite and carbon black.
Claim 20
Dependent Claim
69 words
An improved device for attenuating impinging radar waves by interference, consisting of the combination of an outer radar wave attenuating layer means having a surface reflecting one part of the impinging waves and a wave reflecting backing reflecting the other part of the impinging waves, which have penetrated into the layer means, said backing being a sheet composed essentially of a vulcanized butadiene acrylonitrile copolymer, graphite and carbon black.
Claim 21
Dependent Claim
22 words
The device of claim 16, wherein the butadiene acrylonitrile copolymer, graphite and carbon black are present in about equal proportion, by weight.
Claim 22
Dependent Claim
109 words
An improved device for attenuating impinging radar waves by interference, consisting of the combination of (1) a radar wave attenuating layer means having a surface reflecting one part of the impinging waves, said layer means having a thickness of approximately n lambda /4, wherein n is any odd integer and lambda is the wavelength of the impinging waves measured in the layer means, and (2) a wave reflecting backing reflecting the other part of the impinging waves, which have penetrated into the layer means, said backing being a nonmetallic sheet having a relative dielectric constant of between 20 and 600, and a relative permeability of between 0.9 and 10.
Claim 23
Dependent Claim
109 words
An improved device for attenuating impinging radar waves by interference, consisting of the combination of (1) a radar wave attenuating layer means having a surface reflecting one part of the impinging waves, said layer means having a thickness of approximately n lambda /4, wherein n is any odd integer and lambda is the wavelength of the impinging waves measured in the layer means, and (2) a wave reflecting backing reflecting the other part of the impinging waves, which have penetrated into the layer means, said backing being a nonmetallic sheet having a relative dielectric constant of between 20 and 600, and a relative permeability of between 0.9 and 10.
Claim 24
Dependent Claim
24 words
The device of claim 18, further comprising an outer conductive coating having a resistance of 377 ohms cm. on the wave absorbing layer structure.
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) | 1974-03-01 | 1974-08-31 | 1975-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-01 | 1978-08-31 | 1979-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-01 | 1982-08-31 | 1983-03-02 | $7700.00 | Window Closed / Lapsed |