Electromagnetic-wave-absorbing sheet
US-11152711-B2 · Oct 19, 2021 · US
Electromagnetic wave absorbing composition and electromagnetic wave absorbing body
US11587705B2 · US · B2
| Field | Value |
|---|---|
| Publication number | US-11587705-B2 |
| Application number | US-201816645547-A |
| Country | US |
| Kind code | B2 |
| Filing date | Sep 12, 2018 |
| Priority date | Sep 29, 2017 |
| Publication date | Feb 21, 2023 |
| Grant date | Feb 21, 2023 |
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- Title
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Abstract
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Provided is an electromagnetic-wave absorber composition and an electromagnetic-wave absorber that can favorably absorb a plurality of electromagnetic waves of different frequencies in a high frequency band in or above the millimeter-wave band. The electromagnetic-wave absorber composition includes a magnetic iron oxide that magnetically resonates at a high frequency in or above the millimeter-wave band and a resin binder. The electromagnetic-wave absorber composition has two or more extrema separated from each other on a differential curve obtained by differentiating a magnetic property hysteresis loop at an applied magnetic field intensity of from 16 kOe to −16 kOe. The electromagnetic-wave absorber includes an electromagnetic-wave absorbing layer formed of the above-described electromagnetic-wave absorber composition.
First claim
Opening claim text (preview).
The invention claimed is: 1. An electromagnetic-wave absorber composition, comprising: a magnetic iron oxide that magnetically resonates at a high frequency in or above a millimeter-wave band; and a resin binder, wherein the magnetic iron oxide comprises two or more magnetic iron oxides with different coercive forces, the two or more magnetic iron oxides with different coercive forces comprise two or more kinds of epsilon iron oxides in which part of Fe sites of the epsilon iron oxide crystal is substituted with a trivalent metal element and that have a difference in an electromagnetic-wave absorption frequency of 5 GHz or more from each other, or comprise one or more kinds of epsilon iron oxides in which part of Fe sites of the epsilon iron oxide crystal is substituted with a trivalent metal element and one or more kinds of strontium ferrites, and the electromagnetic-wave absorber composition has two or more extrema separated from each other on a differential curve obtained by differentiating a magnetic property hysteresis loop at an applied magnetic field intensity of from 16 kOe to −16 kOe. 2. The electromagnetic-wave absorber composition according to claim 1 , wherein a coercive force of the magnetic iron oxide is 1200 Oe or more. 3. The electromagnetic-wave absorber composition according to claim 1 , wherein the magnetic iron oxide comprises at least one of epsilon iron oxide, M-type ferrite, and strontium ferrite. 4. The electromagnetic-wave absorber composition according to claim 1 , wherein the magnetic iron oxide comprises at least two of epsilon iron oxide, M-type ferrite, and strontium ferrite. 5. An electromagnetic-wave absorber comprising an electromagnetic-wave absorbing layer formed of the electromagnetic-wave absorber composition according to claim 1 . 6. The electromagnetic-wave absorber according to claim 5 , further comprising an adhesive layer. 7. The electromagnetic-wave absorber according to claim 5 , wherein the electromagnetic-wave absorbing layer is an electromagnetic-wave absorbing sheet formed in a sheet shape.
Assignees
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Classifications
Ferric oxide [Fe2O3] · CPC title
- H01F1/344Primary
Ferrites, e.g. having a cubic spinel structure (X2+O)(Y23+O3), e.g. magnetite Fe3O4 · CPC title
- H05K9/0083Primary
comprising electro-conductive non-fibrous particles embedded in an electrically insulating supporting structure, e.g. powder, flakes, whiskers (H05K9/0086 takes precedence) · CPC title
non-metallic substances, e.g. ferrites · CPC title
Compounds of iron · CPC title
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Frequently asked questions
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- What does patent US11587705B2 cover?
- Provided is an electromagnetic-wave absorber composition and an electromagnetic-wave absorber that can favorably absorb a plurality of electromagnetic waves of different frequencies in a high frequency band in or above the millimeter-wave band. The electromagnetic-wave absorber composition includes a magnetic iron oxide that magnetically resonates at a high frequency in or above the millimeter-…
- Who is the assignee on this patent?
- Maxell Ltd
- What technology area does this patent fall under?
- Primary CPC classification H01F1/344. Mapped technology areas include Electricity.
- When was this patent published?
- Publication date Tue Feb 21 2023 00:00:00 GMT+0000 (Coordinated Universal Time) (B2). Legal status and post-grant events are not shown on this page.
- What related patents are in patentsdb?
- We list 3 related publications on this page (citations in our corpus or others sharing the same primary CPC).