JP7339246B2 - 電磁波吸収体 - Google Patents
電磁波吸収体 Download PDFInfo
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- JP7339246B2 JP7339246B2 JP2020523081A JP2020523081A JP7339246B2 JP 7339246 B2 JP7339246 B2 JP 7339246B2 JP 2020523081 A JP2020523081 A JP 2020523081A JP 2020523081 A JP2020523081 A JP 2020523081A JP 7339246 B2 JP7339246 B2 JP 7339246B2
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- electromagnetic wave
- wave absorbing
- wave absorber
- iron oxide
- magnetic iron
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
- H01F1/34—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials non-metallic substances, e.g. ferrites
- H01F1/342—Oxides
- H01F1/344—Ferrites, e.g. having a cubic spinel structure (X2+O)(Y23+O3), e.g. magnetite Fe3O4
- H01F1/348—Hexaferrites with decreased hardness or anisotropy, i.e. with increased permeability in the microwave (GHz) range, e.g. having a hexagonal crystallographic structure
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
- H01F1/10—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials non-metallic substances, e.g. ferrites, e.g. [(Ba,Sr)O(Fe2O3)6] ferrites with hexagonal structure
- H01F1/11—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials non-metallic substances, e.g. ferrites, e.g. [(Ba,Sr)O(Fe2O3)6] ferrites with hexagonal structure in the form of particles
- H01F1/113—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials non-metallic substances, e.g. ferrites, e.g. [(Ba,Sr)O(Fe2O3)6] ferrites with hexagonal structure in the form of particles in a bonding agent
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
- H01F1/34—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials non-metallic substances, e.g. ferrites
- H01F1/36—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials non-metallic substances, e.g. ferrites in the form of particles
- H01F1/37—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials non-metallic substances, e.g. ferrites in the form of particles in a bonding agent
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q17/00—Devices for absorbing waves radiated from an antenna; Combinations of such devices with active antenna elements or systems
- H01Q17/002—Devices for absorbing waves radiated from an antenna; Combinations of such devices with active antenna elements or systems using short elongated elements as dissipative material, e.g. metallic threads or flake-like particles
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K9/00—Screening of apparatus or components against electric or magnetic fields
- H05K9/0073—Shielding materials
- H05K9/0081—Electromagnetic shielding materials, e.g. EMI, RFI shielding
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K9/00—Screening of apparatus or components against electric or magnetic fields
- H05K9/0073—Shielding materials
- H05K9/0081—Electromagnetic shielding materials, e.g. EMI, RFI shielding
- H05K9/0083—Electromagnetic shielding materials, e.g. EMI, RFI shielding comprising electro-conductive non-fibrous particles embedded in an electrically insulating supporting structure, e.g. powder, flakes, whiskers
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Power Engineering (AREA)
- Dispersion Chemistry (AREA)
- Electromagnetism (AREA)
- Physics & Mathematics (AREA)
- Crystallography & Structural Chemistry (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
- Adjustment Of The Magnetic Head Position Track Following On Tapes (AREA)
- Polishing Bodies And Polishing Tools (AREA)
- Compounds Of Iron (AREA)
- Hard Magnetic Materials (AREA)
Description
[電磁波吸収シートの構成]
図1は、本実施形態にかかる電磁波吸収体としての電磁波吸収シートの構成を示す断面図である。
本実施形態にかかる電磁波吸収シートでは、電磁波吸収材料として電磁波吸収層1に含まれる磁性酸化鉄1aとして、微細粒子状(粉体)の六方晶フェライト、または、イプシロン磁性酸化鉄を用いている。
本実施形態にかかる電磁波吸収シートの電磁波吸収層1を構成するゴム製のバインダー1bには、天然ゴム(NR)、イソプレンゴム(IR)、ブタジエンゴム(BR)、ブチルゴム(IIR)、ニトリルゴム(NBR)、エチレン・プロピレンゴム(EPDM)、クロロブレンゴム(CR)、アクリルゴム(ACM)、クロロスルホン化ポリエチレンゴム(CSR)、ウレタンゴム(PUR)、シリコーンゴム(Q)、フッ素ゴム(FKM)、エチレン・酢酸ビニルゴム(EVA)、エピクロルヒドリンゴム(CO)、多硫化ゴム(T)、ウレタンゴム(U)など、各種のゴム材料を利用することができる。
電磁波吸収性材料である磁性酸化鉄をゴム製バインダー内で良好に分散させるために、分散剤を用いることがより好ましい。
ここで、本実施形態にかかる電磁波吸収シートの電磁波吸収層1の作製方法について説明する。
図1に示すように、本実施形態にかかる電磁波吸収シートは、電磁波吸収層1の背面に粘着層2が形成されている。
本実施形態にかかる電磁波吸収シートでは、1GHzにおける複素比誘電率の実部が5.5以下となっている。このようにすることで、電磁波吸収シートの入力インピーダンス値を空気中(真空)のインピーダンス値である377Ωに近づけることができる。このため、空気と電磁波吸収シートとの間のインピーダンス値の差異によって生じる、空気中を伝搬した電磁波が電磁波吸収シートに入射する際の反射を低減することができ、より多くの電磁波が電磁波吸収シート内に入射して電磁波吸収材料である磁性酸化鉄粉によって吸収される。
1a 磁性酸化鉄粉(電磁波吸収材料)
1b バインダー
Claims (7)
- ミリ波帯域以上の周波数で磁気共鳴する磁性酸化鉄と有機材料のバインダーとを含む電磁波吸収層を備えた透過型の電磁波吸収体であって、
1GHzにおける複素比誘電率の実部の値が、前記磁性酸化鉄が含まれていない状態の数値より大きく、かつ、5.43以下であることを特徴とする、電磁波吸収体。 - 1GHzにおける複素比誘電率の実部が4.2以下である、請求項1に記載の電磁波吸収体。
- 前記磁性酸化鉄として、六方晶フェライト、または、イプシロン磁性酸化鉄のいずれかを含む、請求項1または2に記載の電磁波吸収体。
- 前記六方晶フェライトがストロンチウムフェライト、または、バリウムフェライトであり、Feサイトの一部が3価の金属原子で置換されている、請求項3に記載の電磁波吸収体。
- 前記イプシロン磁性酸化鉄のFeサイトの一部が3価の金属原子で置換されている、請求項3に記載の電磁波吸収体。
- 前記バインダーが、熱硬化性ゴム、熱可塑性エラストマー、または、熱可塑性樹脂のいずれかを含む、請求項1~5のいずれかに記載の電磁波吸収体。
- 前記電磁波吸収層がシート状に形成された、請求項1~6のいずれかに記載の電磁波吸収体。
Priority Applications (1)
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JP2023095478A JP2023107871A (ja) | 2018-06-04 | 2023-06-09 | 電磁波吸収体 |
Applications Claiming Priority (3)
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JP2018107184 | 2018-06-04 | ||
JP2018107184 | 2018-06-04 | ||
PCT/JP2019/021837 WO2019235393A1 (ja) | 2018-06-04 | 2019-05-31 | 電磁波吸収体 |
Related Child Applications (1)
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JP2023095478A Division JP2023107871A (ja) | 2018-06-04 | 2023-06-09 | 電磁波吸収体 |
Publications (2)
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JPWO2019235393A1 JPWO2019235393A1 (ja) | 2021-06-24 |
JP7339246B2 true JP7339246B2 (ja) | 2023-09-05 |
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JP2020523081A Active JP7339246B2 (ja) | 2018-06-04 | 2019-05-31 | 電磁波吸収体 |
JP2023095478A Pending JP2023107871A (ja) | 2018-06-04 | 2023-06-09 | 電磁波吸収体 |
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JP2023095478A Pending JP2023107871A (ja) | 2018-06-04 | 2023-06-09 | 電磁波吸収体 |
Country Status (6)
Country | Link |
---|---|
US (1) | US20210225567A1 (ja) |
EP (1) | EP3817533A4 (ja) |
JP (2) | JP7339246B2 (ja) |
CN (1) | CN112237057B (ja) |
TW (1) | TWI783148B (ja) |
WO (1) | WO2019235393A1 (ja) |
Families Citing this family (1)
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JP7111636B2 (ja) * | 2019-02-05 | 2022-08-02 | 国立大学法人 東京大学 | 鉄系酸化物磁性粉およびその製造方法 |
Citations (2)
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WO2018084235A1 (ja) | 2016-11-04 | 2018-05-11 | マクセルホールディングス株式会社 | 電磁波吸収シート |
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-
2019
- 2019-05-21 TW TW108117462A patent/TWI783148B/zh active
- 2019-05-31 US US15/734,714 patent/US20210225567A1/en active Pending
- 2019-05-31 CN CN201980037546.5A patent/CN112237057B/zh active Active
- 2019-05-31 WO PCT/JP2019/021837 patent/WO2019235393A1/ja unknown
- 2019-05-31 EP EP19815938.6A patent/EP3817533A4/en active Pending
- 2019-05-31 JP JP2020523081A patent/JP7339246B2/ja active Active
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2023
- 2023-06-09 JP JP2023095478A patent/JP2023107871A/ja active Pending
Patent Citations (2)
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JP2013213198A (ja) | 2012-03-09 | 2013-10-17 | Nitto Denko Corp | 多孔質樹脂シート及びその製造方法 |
WO2018084235A1 (ja) | 2016-11-04 | 2018-05-11 | マクセルホールディングス株式会社 | 電磁波吸収シート |
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Publication number | Publication date |
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CN112237057A (zh) | 2021-01-15 |
EP3817533A1 (en) | 2021-05-05 |
US20210225567A1 (en) | 2021-07-22 |
JP2023107871A (ja) | 2023-08-03 |
TW202004786A (zh) | 2020-01-16 |
JPWO2019235393A1 (ja) | 2021-06-24 |
CN112237057B (zh) | 2023-09-12 |
EP3817533A4 (en) | 2022-03-23 |
WO2019235393A1 (ja) | 2019-12-12 |
TWI783148B (zh) | 2022-11-11 |
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