US4003840A
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Microwave absorber
Assignee: TDK Corp
•
Filing: 1975-05-12
•
Granted: 1977-01-18
•
Expires: 1995-05-12
Abstract
Abstract Microwave absorber comprising a mixture of ferrite powder having particle size of less than 1.65 mm and an organic high molecular weight compound.
Inventors
- 👤 Ken Ishino
- 👤 Takashi Watanabe
- 👤 Yasuo Hashimoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 10:46
CPC Classifications
H; H01; H01Q; H01Q17/00; B; B65; B65D; B65D81/00; B65D81/34; B65D81/3446; H01P; H01P1/00; H01P1/22; H01P1/225; H05; H05B; H05B6/00; H05B6/64; B65D2581/00; B65D2581/34; B65D2581/3437; B65D2581/3439; B65D2581/344; B65D2581/3443; B65D2581/3448; B65D2581/3463; B65D2581/3464; B65D2581/3471; B65D2581/3477; B65D2581/3479; B65D2581/3486; B65D2581/3494
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
226 words
A microwave absorber consisting essentially of a mixture of from 0.2 to 0.9 part by volume of a ferrite powder and from 0.8 to 0.1 part by volume of an organic high molecular compound, said ferrite powder being a powder having a particle size of less than 1.65 mm of a ferrite having the general formula MFe 2 O 4 in which M is selected from the group consisting of manganese, nickel, copper, zinc, magnesium and cobalt and having an initial permeability of more than 300 at 10 kHz, said organic high molecular compound being a thermosetting resin selected from the group consisting of phenol resin, polyester resin, epoxy resin and silicone resin; or a thermoplastic resin selected from the group consisting of polyvinyl chloride, polyethylene and polypropylene; or a natural and synthetic rubber selected from the group consisting of polychloroprene, acrylonitrile-butadiene-styrene and fluorine-contained rubber, said ferrite powder in a certain particle size range being used for absorbing the microwave in a certain frequency range as shown below: ______________________________________
Particle size of ferrite
Frequency of
powder microwave
______________________________________
1.65 mm - 701 μ 500 MHz - 1.5 GHz
701 μ - 351 μ 1.0 GHz - 2.0 GHz
351 μ - 104 μ 1.8 GHz - 3.0 GHz
104 μ - 43 μ 2.5 GHz - 7.5 GHz
<43 μ 6.0 GHz - 12.0 GHz.
______________________________________
Claim 2
Dependent Claim
226 words
A microwave absorber consisting essentially of a mixture of from 0.2 to 0.9 part by volume of a ferrite powder and from 0.8 to 0.1 part by volume of an organic high molecular compound, said ferrite powder being a powder having a particle size of less than 1.65 mm of a ferrite having the general formula MFe 2 O 4 in which M is selected from the group consisting of manganese, nickel, copper, zinc, magnesium and cobalt and having an initial permeability of more than 300 at 10 kHz, said organic high molecular compound being a thermosetting resin selected from the group consisting of phenol resin, polyester resin, epoxy resin and silicone resin; or a thermoplastic resin selected from the group consisting of polyvinyl chloride, polyethylene and polypropylene; or a natural and synthetic rubber selected from the group consisting of polychloroprene, acrylonitrile-butadiene-styrene and fluorine-contained rubber, said ferrite powder in a certain particle size range being used for absorbing the microwave in a certain frequency range as shown below: ______________________________________
Particle size of ferrite
Frequency of
powder microwave
______________________________________
1.65 mm - 701 μ 500 MHz - 1.5 GHz
701 μ - 351 μ 1.0 GHz - 2.0 GHz
351 μ - 104 μ 1.8 GHz - 3.0 GHz
104 μ - 43 μ 2.5 GHz - 7.5 GHz
<43 μ 6.0 GHz - 12.0 GHz.
______________________________________
Claim 3
Dependent Claim
72 words
A microwave absorber according to claim 1 wherein the organic high molecular weight compound is at least one member selected from the group consisting of a thermosetting resin selected from a group consisting of phenol resin, polyester resin, epoxy resin and silicone resin; thermoplastic resin selected from the group consisting of polyvinyl chloride, polyethylene and polypropylene; natural rubber and synthetic rubber selected from the group consisting of polychloroprene, acrylonitrile-butadiene-styrene and fluorine-contained rubber.
Claim 4
Dependent Claim
46 words
A microwave absorber according to claim 1 wherein the ferrite powder and the organic high molecular weight compound are mixed in a ratio as shown below: ______________________________________
Ferrite powder 0.2 - 0.9 part by volume
Organic high weight
0.8 - 0.1 part by volume
compound
______________________________________
Claim 5
Dependent Claim
28 words
A microwave absorber according to claim 1 in which said divalent metal is a member selected from the group consisting of manganese, nickel, copper, zinc, magnesium and cobalt.
Claim 6
Dependent Claim
226 words
A microwave absorber consisting essentially of a mixture of from 0.2 to 0.9 part by volume of a ferrite powder and from 0.8 to 0.1 part by volume of an organic high molecular compound, said ferrite powder being a powder having a particle size of less than 1.65 mm of a ferrite having the general formula MFe 2 O 4 in which M is selected from the group consisting of manganese, nickel, copper, zinc, magnesium and cobalt and having an initial permeability of less than 300 at 10 kHz, said organic high molecular compound being a thermosetting resin selected from the group consisting of phenol resin, polyester resin, epoxy resin and silicone resin; or a thermoplastic resin selected from the group consisting of polyvinyl chloride, polyethylene and polypropylene; or a natural and synthetic rubber selected from the group consisting of polychloroprene, acrylonitrile-butadiene-styrene and fluorine-contained rubber, said ferrite powder in a certain particle size range being used for absorbing the microwave in a certain frequency range as shown below: ______________________________________
Particle size of ferrite
powder Frequency of microwave
______________________________________
1.65 mm - 701 μ 1.0 GHz - 3.0 GHz
701 μ - 351 μ 2.0 GHz - 4.5 GHz
351 μ - 104 μ 4.0 GHz - 6.0 GHz
104 μ - 43 μ 5.0 GHz - 7.5 GHz
<43 μ 6.0 GHz - 12.0 GHz.
______________________________________
Claim 7
Dependent Claim
226 words
A microwave absorber consisting essentially of a mixture of from 0.2 to 0.9 part by volume of a ferrite powder and from 0.8 to 0.1 part by volume of an organic high molecular compound, said ferrite powder being a powder having a particle size of less than 1.65 mm of a ferrite having the general formula MFe 2 O 4 in which M is selected from the group consisting of manganese, nickel, copper, zinc, magnesium and cobalt and having an initial permeability of less than 300 at 10 kHz, said organic high molecular compound being a thermosetting resin selected from the group consisting of phenol resin, polyester resin, epoxy resin and silicone resin; or a thermoplastic resin selected from the group consisting of polyvinyl chloride, polyethylene and polypropylene; or a natural and synthetic rubber selected from the group consisting of polychloroprene, acrylonitrile-butadiene-styrene and fluorine-contained rubber, said ferrite powder in a certain particle size range being used for absorbing the microwave in a certain frequency range as shown below: ______________________________________
Particle size of ferrite
powder Frequency of microwave
______________________________________
1.65 mm - 701 μ 1.0 GHz - 3.0 GHz
701 μ - 351 μ 2.0 GHz - 4.5 GHz
351 μ - 104 μ 4.0 GHz - 6.0 GHz
104 μ - 43 μ 5.0 GHz - 7.5 GHz
<43 μ 6.0 GHz - 12.0 GHz.
______________________________________
Claim 8
Dependent Claim
27 words
A microwave absorber according to claim 5 wherein said divalent metal is a member selected from the group consisting of manganese, nickel, copper, zinc, magnesium and cobalt.
Claim 9
Dependent Claim
72 words
A microwave absorber according to claim 5 wherein the organic high molecular weight compound is at least one member selected from the group consisting of a thermal setting resin selected from the group consisting of phenol resin, polyester resin, epoxy resin and silicone resin; thermoplastic resins selected from the group consisting of polyvinyl chloride, polyethylene and polypropylene; natural and synthetic rubber selected from the group consisting of polychloroprene, acrylonitrile-butadiene-styrene and fluorine-contained rubber.
Claim 10
Dependent Claim
41 words
A microwave absorber according to claim 5 wherein the ferrite powder and the organic high molecular weight compounds are mixed in the following ratio: ______________________________________
ferrite powder 0.2-0.9 parts by volume
organic high molecular
weight compound 0.8-0.1 part by volume.
______________________________________
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) | 1980-01-18 | 1980-07-19 | 1981-01-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-01-18 | 1984-07-19 | 1985-01-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-01-18 | 1988-07-19 | 1989-01-18 | $7700.00 | Window Closed / Lapsed |