US3568196A
Expired / Lapsed
US
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Radio frequency absorber
Assignee: Raytheon Co
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Filing: 1969-02-06
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Granted: 1971-03-02
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Expires: 1989-02-06
Abstract
Abstract An absorber for radio frequency energy using incombustible materials to minimize adverse effects from the conversion of such energy to heat, including a fibrous mat of nonabsorbing material in which the absorbing material is distributed in such a manner that discontinuities in the index of refraction, meaning always the electrical index, in the path of the energy to be absorbed are minimized.
Inventors
- 👤 Richard O Bayrd
- 👤 Raymond P Tuinila
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:57
CPC Classifications
H; H01; H01Q; H01Q17/00; H01Q17/002
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
72 words
An absorber for radio frequency energy comprising: a. a base, fabricated from randomly intertwined fibers of an inorganic nonconducting material having an index of refraction approximating the index of reFraction of air to form a sheet of such material; and b. an energy absorbing material disposed in the interstices between such fibers, the density of such energy absorbing material decreasing from a maximum at one surface of the base to zero therewithin.
Claim 2
Dependent Claim
72 words
An absorber for radio frequency energy comprising: a. a base, fabricated from randomly intertwined fibers of an inorganic nonconducting material having an index of refraction approximating the index of reFraction of air to form a sheet of such material; and b. an energy absorbing material disposed in the interstices between such fibers, the density of such energy absorbing material decreasing from a maximum at one surface of the base to zero therewithin.
Claim 3
Dependent Claim
36 words
An absorber as in claim 1, wherein the randomly intertwined fibers of an inorganic nonconducting material are cast fibers of alumina silica to form the sheet in a desired shape and to adjust the density thereof.
Claim 4
Dependent Claim
20 words
An absorber as in claim 2 wherein the energy absorbing material consists of particles of an electrically conductive incombustible material.
Claim 5
Dependent Claim
15 words
An absorber as in claim 2 wherein the energy absorbing material is an incombustible liquid.
Claim 6
Dependent Claim
12 words
An absorber as in claim 4 wherein the incombustible liquid is water.
Claim 7
Independent Claim
110 words
A method of absorbing radio frequency energy comprising the steps of: a. wetting the first surface of a sheet of a fibrous nonconducting material with an incombustible liquid to partially impregnate such sheet, such liquid being convertible into its gaseous phase by radio frequency energy impinging thereon; b. irradiating the liquid, through the second surface of such sheet, with radio frequency energy to be absorbed, thereby to convert a portion of the liquid to its gaseous phase and absorb such radio frequency energy; and c. rewetting the first surface of the sheet with additional liquid to replace the amount thereof converted to its gaseous phase by such radio frequency energy.
Claim 8
Independent Claim
110 words
A method of absorbing radio frequency energy comprising the steps of: a. wetting the first surface of a sheet of a fibrous nonconducting material with an incombustible liquid to partially impregnate such sheet, such liquid being convertible into its gaseous phase by radio frequency energy impinging thereon; b. irradiating the liquid, through the second surface of such sheet, with radio frequency energy to be absorbed, thereby to convert a portion of the liquid to its gaseous phase and absorb such radio frequency energy; and c. rewetting the first surface of the sheet with additional liquid to replace the amount thereof converted to its gaseous phase by such radio frequency energy.
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 |