JPH0527059A - Composite body for radio wave absorption - Google Patents
Composite body for radio wave absorptionInfo
- Publication number
- JPH0527059A JPH0527059A JP3199851A JP19985191A JPH0527059A JP H0527059 A JPH0527059 A JP H0527059A JP 3199851 A JP3199851 A JP 3199851A JP 19985191 A JP19985191 A JP 19985191A JP H0527059 A JPH0527059 A JP H0527059A
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- metal alloy
- magnetic metal
- loss
- wave absorption
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Hard Magnetic Materials (AREA)
- Soft Magnetic Materials (AREA)
- Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
- Details Of Measuring And Other Instruments (AREA)
- Powder Metallurgy (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、磁性合金粉末を用いた
電波吸収用複合体に関し、更に詳しくは、磁性合金粉末
を絶縁体中に一定量、一定方向に配向含有させた複合体
よりなり、使用される周波数域において、磁気損失と誘
電損失とを合せて利用することにより、電波吸収特性を
改良した電波吸収用複合体に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite for absorbing radio waves using a magnetic alloy powder, and more specifically, it comprises a composite in which a magnetic alloy powder is contained in an insulator in a certain amount in a certain direction. The present invention relates to a radio wave absorption composite body having improved radio wave absorption characteristics by utilizing magnetic loss and dielectric loss together in the frequency range used.
【０００２】[0002]
【従来の技術】磁性体を用いた電波吸収材として、フェ
ライト系の磁性材料、例えばNi−Zn系フェライトが実用
化されている。これはNiＯx −ZnＯ1-x −Fe2 Ｏ3 なる
組成をもつスピネル構造の複合酸化物で、タイル状のセ
ラミックス焼結体やその粉末をゴムと混合したものが、
実用或いは提案されている。2. Description of the Related Art Ferrite magnetic materials such as Ni-Zn ferrite have been put to practical use as radio wave absorbers using magnetic materials. This is a composite oxide of spinel structure having a NiO x -ZnO 1-x -Fe 2 O 3 having a composition, a tiled ceramic sintered body and the powder is a mixture with the rubber,
Practical or proposed.
【０００３】然しながら、これらはフェライトの磁気損
失のみを利用するもので、吸収特性も充分なものとは言
えない。それで吸収特性を改良するため、金属反射板を
タイルに裏打ちし、反射波を再吸収したり、吸収体面で
の反射波と金属反射板での反射波との干渉を利用したり
している。However, these utilize only the magnetic loss of ferrite, and the absorption characteristics cannot be said to be sufficient. Therefore, in order to improve the absorption characteristics, the metal reflection plate is lined with tiles to re-absorb the reflected wave, or the interference between the reflected wave on the absorber surface and the reflected wave on the metal reflector is used.
【０００４】一方金属磁性体を電波吸収用材料に用いる
ことは、特性が不十分でこれまで提案されていない。一
般的に使用されている例えばＴＶ周波数域は１００ＭＨ
Z 〜７００ＭＨZ であり、衛星放送は２ＧＨZである
が、このような高い周波数域で金属系磁性体を用いる
と、使用時の透磁率の値が著しく小さな値となり、電波
吸収特性を示さないからである。従って金属系磁性合金
は電波吸収用材料として実用化されていない。このこと
は磁性金属として高透磁率磁性合金を用いても同様であ
る。On the other hand, the use of a metal magnetic material as a radio wave absorbing material has not been proposed so far because of its insufficient characteristics. A commonly used TV frequency range is 100 MHz, for example.
Z ～700MH is Z, although satellite is 2GH Z, when such a high frequency region using a metal magnetic body, the value of permeability in use becomes significantly small value, do not exhibit wave absorption characteristics Because. Therefore, the metallic magnetic alloy has not been put to practical use as a material for absorbing radio waves. This is the same even when a high-permeability magnetic alloy is used as the magnetic metal.
【０００５】[0005]
【発明が解決しようとする課題】本発明は磁気損失並び
に誘電損失を合せもつ磁性金属合金粉末を、絶縁体内に
一定量一定方向に配向配列させることにより、新たにす
ぐれた電波吸収特性を示す電波吸収用複合体を提供する
ことを課題としている。DISCLOSURE OF THE INVENTION According to the present invention, a magnetic metal alloy powder having both magnetic loss and dielectric loss is orientated and arranged in a certain amount in a constant direction in an insulator to provide a radio wave exhibiting a new excellent radio wave absorption characteristic. It is an object to provide a composite for absorption.
【０００６】[0006]
【課題を解決するための手段】本発明は、本出願人の出
願した特願平３−６１００５号の技術を改良発展させた
ものであり、一定の形状、寸法と電気抵抗率を有する磁
性金属合金粉末を、絶縁体例えばゴム、プラスチックな
どの高分子材料中に必要量、一定方向に配向整列させた
複合体として製造される。The present invention is an improvement and development of the technique of Japanese Patent Application No. 3-61005 filed by the present applicant, which is a magnetic metal having a constant shape, size and electric resistivity. The alloy powder is manufactured as a composite in which a required amount of the alloy powder is oriented and aligned in a certain direction in a polymer material such as rubber or plastic.
【０００７】一般に高周波域における物質の磁気損失や
誘電損失は、その物質の基本的特性を表わすものであ
る。前者は、複素透磁率μ* ＝μ′−ｊμ″（又は損失
角tanδ＝μ″／μ′）、後者ついては複素誘電率ε*
＝ε′−ｊε″（又は損失角tan δ＝ε″／ε′）で表
わされる事が知られている。複素透磁率及び複素誘電率
が分かれば、この物質の反射率ｒ（入射電磁波が物質に
垂直入射した場合に物質表面で反射される割合）や表皮
深さｓ（入射電磁波が物質中で１／ｅに減衰するまでの
吸収層の厚み）が求められ、物質の吸収特性を知ること
ができる。Generally, magnetic loss and dielectric loss of a substance in a high frequency range represent basic characteristics of the substance. The former is complex permeability μ * = μ′−jμ ″ (or loss angle tan δ = μ ″ / μ ′), and the latter is complex permittivity ε *.
= Ε′-jε ″ (or loss angle tan δ = ε ″ / ε ′) is known. If the complex magnetic permeability and complex permittivity are known, the reflectance r of this substance (the ratio of the incident electromagnetic wave reflected by the surface of the substance when it is vertically incident on the substance) and the skin depth s (the incident electromagnetic wave in the substance is 1 / The thickness of the absorption layer until it decays to e) is obtained, and the absorption characteristics of the substance can be known.
【０００８】本発明は、高周波域において必要とする複
素透磁率（μ* ＝μ′−ｊμ″）と複素誘電率（ε* ＝
ε′−ｊε″）をえるため種々研究を重ねたもので、一
定の形状、寸法と電気抵抗率を有する高透磁率磁性金属
合金を絶縁体中に混合させ、更にその合金を一定方向に
配合整列させることにより目的を達成可能としている。According to the present invention, the complex magnetic permeability (μ * = μ′−jμ ″) and complex permittivity (ε * =) required in the high frequency range.
In order to obtain ε′-jε ″), various researches have been carried out. A high-permeability magnetic metal alloy having a certain shape, size and electric resistivity is mixed in an insulator, and the alloy is blended in a certain direction. By aligning them, the purpose can be achieved.
【０００９】本発明の制御された磁性金属合金粉末は、
目的とする周波数域で所望の複素透磁率（磁気損失）μ
* を得ると共に、誘電体（絶縁体）中に複合され、導電
性フィラーとしても作用し、この形状、寸法及び電気抵
抗率の制御が、複素誘電率ε* （誘電損失）をも生じさ
せる事により吸収特性を改良するものである。The controlled magnetic metal alloy powder of the present invention comprises:
Desired complex permeability (magnetic loss) μ in the target frequency range
In addition to obtaining * , it also acts as a conductive filler by being compounded in a dielectric (insulator), and controlling its shape, dimensions and electrical resistivity also causes a complex dielectric constant ε * (dielectric loss). Improves the absorption characteristics.
【００１０】電磁波は、電界成分と磁界成分とを合せ持
った波であり、この電界成分と磁界成分との比は、空間
インピーダンスＺ0 として表され、遠方界においては３
７７Ωとなっている。磁気損失は磁界成分に、誘電損失
は電界成分の吸収に寄与する。従って、本発明では磁気
損失と誘電損失とを共に利用する事により、吸収特性を
改良している。An electromagnetic wave is a wave having both an electric field component and a magnetic field component, and the ratio of the electric field component and the magnetic field component is expressed as a spatial impedance Z 0 , which is 3 in the far field.
It is 77Ω. The magnetic loss contributes to the magnetic field component, and the dielectric loss contributes to the absorption of the electric field component. Therefore, in the present invention, the absorption characteristics are improved by utilizing both the magnetic loss and the dielectric loss.
【００１１】また図１から判るように、磁界成分と電界
成分の方向は、進行方向に対してそれぞれ垂直であるた
め、電波吸収複合体内の磁性合金を電磁波の磁界成分と
同じ方向に（図２）整列させる事により、吸収特性を更
に向上させる事ができる。Further, as can be seen from FIG. 1, the directions of the magnetic field component and the electric field component are respectively perpendicular to the traveling direction, so that the magnetic alloy in the electromagnetic wave absorbing complex is oriented in the same direction as the magnetic field component of the electromagnetic wave (see FIG. 2). ) By aligning, the absorption characteristics can be further improved.
【００１２】上記したように、本発明において使用する
軟磁性金属としては、磁気損失や誘電損失が使用される
極めて高い周波数域において望ましい値となるよう、高
電気抵抗率を有し、しかも所望の形状、寸法である磁性
合金を採用する必要がある。更には高透磁率合金の採用
が特性の向上のために望ましい。As described above, the soft magnetic metal used in the present invention has a high electric resistivity so that the magnetic loss and the dielectric loss have desired values in an extremely high frequency range, and further, it is desirable. It is necessary to adopt a magnetic alloy that is shaped and dimensioned. Furthermore, the adoption of a high magnetic permeability alloy is desirable for improving the characteristics.
【００１３】本発明にて使用される磁性金属合金は、具
体的には電気抵抗率ρ≧８０μΩ−cm、好ましくはρ≧
１００μΩ−cmを有する磁性金属合金である。よく知ら
れている高透磁率アモルファス磁性金属合金類、例えば
Fe−Si−Ｂ系、Co−Fe−Si−Ｂ系などの磁性金属合金、
Fe−Al−Si系（センダスト系）等は使用に好ましい磁性
金属合金であり、特にCo−Fe−Si−Ｂ系アモルファス磁
性金属合金は好結果が得られる。磁性金属合金であって
もパーマロイ等は電気抵抗率が低く望ましい結果は得ら
れない。The magnetic metal alloy used in the present invention has a specific electrical resistivity ρ ≧ 80 μΩ-cm, preferably ρ ≧.
It is a magnetic metal alloy having 100 μΩ-cm. Well-known high magnetic permeability amorphous magnetic metal alloys, for example
Magnetic metal alloys such as Fe-Si-B type and Co-Fe-Si-B type,
Fe-Al-Si type (Sendust type) and the like are preferable magnetic metal alloys for use, and particularly Co-Fe-Si-B type amorphous magnetic metal alloys give good results. Even with a magnetic metal alloy, permalloy or the like has a low electric resistivity, and a desired result cannot be obtained.
【００１４】また使用する磁性金属合金の形状、寸法
は、電波吸収材の磁気損失（複素透磁率）や誘電損失
（複素誘電率）特性に重要な影響を及ぼし、球状、塊状
のものを用いても好ましい結果は得られず、針状、繊維
状或いはフレーク状等のアスペクト比の大きい形状のも
のの使用が好ましい結果を与える。従って本発明におい
ては、高透磁率磁性金属合金粉末のアスペクト比５０以
上のものを使用する。アスペクト比があまり大きくなる
と、絶縁体中に高透磁率磁性金属合金粉末を所望量複合
化する場合、隣接粉末との接触を生じ、個々の粉末間の
絶縁を保つことが難しくなり、電波吸収性が阻害される
可能性がある。このような場合には個々の粉末を予め絶
縁体でコーティングしておくことが効果的である。The shape and dimensions of the magnetic metal alloy used have an important effect on the magnetic loss (complex permeability) and dielectric loss (complex permittivity) characteristics of the electromagnetic wave absorber, and spherical or lumpy ones are used. However, favorable results are not obtained, and the use of needles, fibers or flakes having a large aspect ratio gives favorable results. Therefore, in the present invention, a high magnetic permeability magnetic metal alloy powder having an aspect ratio of 50 or more is used. If the aspect ratio becomes too large, when compounding a desired amount of high-permeability magnetic metal alloy powder in the insulator, contact with adjacent powder will occur, making it difficult to maintain insulation between individual powders, resulting in electromagnetic wave absorption. May be hindered. In such a case, it is effective to coat each powder with an insulator in advance.
【００１５】又使用する磁性金属合金粉末の形状と共に
寸法も重要な因子となる。本願発明においては上述形状
体の最小軸寸法を１〜１００μｍにとる。より好ましい
寸法は１０〜５０μｍである。この値が１μｍ以下では
粉末の透磁率が低下し、１００μｍ以上では透磁率の周
波数特性が劣化し、何れも吸収特性を阻害し、好ましい
結果がえられない。In addition to the shape of the magnetic metal alloy powder used, the size is also an important factor. In the present invention, the minimum axial dimension of the above-mentioned shaped body is set to 1 to 100 μm. A more preferable size is 10 to 50 μm. When this value is 1 μm or less, the magnetic permeability of the powder is lowered, and when it is 100 μm or more, the frequency characteristic of the magnetic permeability is deteriorated, and any of them impairs the absorption characteristics, and a desirable result cannot be obtained.
【００１６】誘電損失については前述したように絶縁体
中に混合する磁性体其のものを導電性フィラーとして併
用するもので、其の形状、寸法や電気抵抗率は直接、誘
電損失（複素誘電率）に大きな影響を与える。球状、塊
状に比べアスペクト比の大きい粒体は望ましい誘電損失
が得られたが前者は望ましい結果がえられなかった。電
気抵抗率が低い場合も誘電損失に好ましい結果を与えな
かった。Regarding the dielectric loss, as described above, the magnetic substance mixed in the insulator is also used as the conductive filler, and its shape, size and electric resistivity are directly related to the dielectric loss (complex permittivity). ) Has a great effect on. The particles having a larger aspect ratio than the spherical and lump-like ones gave the desired dielectric loss, but the former did not give the desired result. Even when the electrical resistivity was low, it did not give a favorable result to the dielectric loss.
【００１７】絶縁体中に混合する磁性金属合金粉末の割
合については容積比率で５％以上７０％以下を採用す
る。５％以下では望ましい吸収特性が得られず、７０％
以上になると複合体を経済的に製造する等が困難になる
からである。The volume ratio of the magnetic metal alloy powder mixed in the insulator is 5% or more and 70% or less. If it is less than 5%, the desired absorption characteristics cannot be obtained and 70%
This is because it becomes difficult to economically produce the composite or the like.
【００１８】磁性金属合金は、特開昭５８−６９０７号
公報に開示されるキャビテーション法、即ち熔融金属に
対して濡れ性の小さな表面層を有し、高速で回転してい
るロール表面に熔融金属を供給し、この熔融金属を微細
な熔融金属滴に分断した後、引続いてこの熔融金属滴を
高速で回転する金属回転体に衝突させて急速凝固させる
キャビテーション法にて製作するのが望ましい。特に最
短軸の小さな磁性合金を製造するためには、金属回転体
の回転数を大きくする事により実現できる。またエッチ
ング等化学的方法により、磁性合金の最短軸を小さくす
る事も可能である。The magnetic metal alloy has a cavitation method disclosed in JP-A-58-6907, that is, it has a surface layer having a small wettability with respect to the molten metal, and the molten metal is formed on the surface of a roll rotating at high speed. It is desirable to manufacture by a cavitation method in which the molten metal is divided into fine molten metal droplets, and then the molten metal droplets are subsequently collided with a metal rotating body rotating at a high speed to rapidly solidify. In particular, in order to manufacture a magnetic alloy having a shortest axis, it can be realized by increasing the rotation speed of the metal rotating body. It is also possible to reduce the shortest axis of the magnetic alloy by a chemical method such as etching.
【００１９】[0019]
【実施例１】[Example 1]
【表１】 [Table 1]
【００２０】表１中の各成分の定義は下記の通りであ
る。
Ａ：アモルファス磁性合金 Co−Fe4.5 −Si15−Ｂ12（原子％）
Ｂ：パーマロイ合金 Fe−７５Ni（重量％）
表皮深さｓは電磁波強度が１／ｅに減衰する厚み
ρは電気抵抗率
反射率ｒは入射電磁波が垂直入射した場合物質表面で反
射される割合
反射率ｒ及び表皮深さｓは２００ＭＨZ での値である。The definition of each component in Table 1 is as follows. A: amorphous magnetic alloy Co-Fe 4.5 -Si 15 -B 12 ( atomic%) B: permalloy Fe-75Ni (wt%) Electrical resistivity thickness ρ skin depth s is the intensity of electromagnetic waves is attenuated to 1 / e reflectivity r is the ratio reflectance r and the skin depth s which is reflected by the case material surface where the incident electromagnetic wave is incident perpendicularly is a value of at 200MH Z.
【００２１】No. １，２及び３はvol ％が１０％、No.
４，５及び６は１５％である。磁性金属合金粉末をNo.
１及び４のように、磁界成分と同じ方向に電波吸収複合
体内に配向させた場合（図２）反射率が小さく、表皮深
さが小さくなる。また抵抗率の小さい材料Ｂを使用する
と反射率、表皮深さ共に大となり好ましくない。Nos. 1, 2 and 3 have a vol% of 10% and No.
4, 5 and 6 are 15%. Magnetic metal alloy powder No.
As shown in Nos. 1 and 4, when it is oriented in the electromagnetic wave absorbing complex in the same direction as the magnetic field component (FIG. 2), the reflectance is small and the skin depth is small. Further, when the material B having a low resistivity is used, both the reflectance and the skin depth become large, which is not preferable.
【００２２】[0022]
【実施例２】Example 2
【表２】 [Table 2]
【００２３】Ａは、アモルファス磁性合金 Co−Fe
4.5 −Si15−Ｂ12（原子％）を示すμ′，μ″，ε′，
ε″，ｒ及びｓは表１と同様である。A is an amorphous magnetic alloy Co-Fe.
4.5 −Si 15 −B 12 (atomic%) μ ′, μ ″, ε ′,
ε ″, r and s are the same as in Table 1.
【００２４】表２に実施例１のNo４及び６の各周波数に
おける反射率ｒ及び表皮深さｓを示したが、アモルファ
ス磁性合金を磁界成分と同じ方向に配向混合させると、
ランダム方向に混合させた場合に比し電波吸収効果がす
ぐれることを示した。Table 2 shows the reflectance r and the skin depth s at each frequency of Nos. 4 and 6 of Example 1. When the amorphous magnetic alloy is oriented and mixed in the same direction as the magnetic field component,
It was shown that the electromagnetic wave absorption effect is better than that in the case of mixing in random directions.
【００２５】[0025]
【発明の効果】本発明による電波吸収用複合体は、使用
する磁性金属合金粉末の形状、寸法および導電体との複
合比を選択し、その磁性金属合金粉末を絶縁体中に一定
の方向に配向整列させてなり、磁気損失並びに導電損失
を併用することにより従来にない効果を示す電波吸収用
複合体である。In the composite for absorbing radio waves according to the present invention, the shape, size and composite ratio of the magnetic metal alloy powder to be used with the conductor are selected, and the magnetic metal alloy powder is made to flow in the insulator in a fixed direction. It is an electromagnetic wave absorbing composite that is oriented and aligned and exhibits an effect that has never been obtained by using magnetic loss and conductive loss together.
【図１】電波の伝る方向と電界Ｅ及び磁界Ｈとの関係を
示す図である。FIG. 1 is a diagram showing a relationship between a propagation direction of a radio wave and an electric field E and a magnetic field H.
【図２】磁界成分と同じ方向（平行）に電波吸収複合体
内の磁性金属合金粉末を配向させた場合を示す図であ
る。FIG. 2 is a diagram showing a case where a magnetic metal alloy powder in a radio wave absorption complex is oriented in the same direction (parallel) as a magnetic field component.
【図３】磁界成分に垂直方向に電波吸収複合体内の磁性
金属合金粉末を配合させた場合を示す図である。FIG. 3 is a view showing a case where a magnetic metal alloy powder in a radio wave absorption complex is mixed in a direction perpendicular to a magnetic field component.
Ｅ 電界 Ｈ 磁界 １ 電波吸収複合体 ２ 磁性金属合金粉末 E electric field H magnetic field 1 Radio wave absorption complex 2 Magnetic metal alloy powder
───────────────────────────────────────────────────── フロントページの続き (72)発明者 林 利勝 埼玉県熊谷市熊谷810番地 株式会社リケ ン熊谷事業所内 (72)発明者 鈴木 賢造 埼玉県熊谷市熊谷810番地 株式会社リケ ン熊谷事業所内 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Toshikatsu Hayashi 810 Kumagaya, Kumagaya, Saitama Rike Co., Ltd. Kumagaya Works (72) Inventor Kenzo Suzuki 810 Kumagaya, Kumagaya, Saitama Rike Co., Ltd. Kumagaya Works
Claims (3)
に配向していることを特徴とする電波吸収用複合体。1. A radio wave absorption composite body in which magnetic metal alloy powder is oriented in a certain direction in an insulator.
−cm以上、アスペクト比５０以上、最短軸寸法が１〜１
００μｍである請求項１の電波吸収用複合体。2. The magnetic metal alloy powder has an electrical resistivity of 80 μΩ.
-Cm or more, aspect ratio 50 or more, minimum axis dimension is 1 to 1
The composite for electromagnetic wave absorption according to claim 1, which has a thickness of 00 μm.
である請求項１又は２の電波吸収用複合体。3. The volume ratio of the magnetic metal alloy powder is 5 to 70%.
The radio wave absorption composite body according to claim 1 or 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3199851A JPH0527059A (en) | 1991-07-16 | 1991-07-16 | Composite body for radio wave absorption |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3199851A JPH0527059A (en) | 1991-07-16 | 1991-07-16 | Composite body for radio wave absorption |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0527059A true JPH0527059A (en) | 1993-02-05 |
Family
ID=16414712
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3199851A Pending JPH0527059A (en) | 1991-07-16 | 1991-07-16 | Composite body for radio wave absorption |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0527059A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07212079A (en) * | 1994-01-20 | 1995-08-11 | Tokin Corp | Electromagnetic wave interference suppressor |
| JP2002280208A (en) * | 2001-03-22 | 2002-09-27 | Mitsubishi Cable Ind Ltd | Wave absorber |
| JP2002299648A (en) * | 2001-03-30 | 2002-10-11 | Hitachi Ltd | Optical transmitting/receiving module |
| JP2019110166A (en) * | 2017-12-15 | 2019-07-04 | 株式会社トーキン | Noise suppression sheet |
-
1991
- 1991-07-16 JP JP3199851A patent/JPH0527059A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07212079A (en) * | 1994-01-20 | 1995-08-11 | Tokin Corp | Electromagnetic wave interference suppressor |
| JP2002280208A (en) * | 2001-03-22 | 2002-09-27 | Mitsubishi Cable Ind Ltd | Wave absorber |
| JP2002299648A (en) * | 2001-03-30 | 2002-10-11 | Hitachi Ltd | Optical transmitting/receiving module |
| JP2019110166A (en) * | 2017-12-15 | 2019-07-04 | 株式会社トーキン | Noise suppression sheet |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Wei et al. | Techniques to enhance magnetic permeability in microwave absorbing materials | |
| Idris et al. | Recent developments of smart electromagnetic absorbers based polymer-composites at gigahertz frequencies | |
| JP5175884B2 (en) | Nanoparticle composite material, antenna device using the same, and electromagnetic wave absorber | |
| Hekmatara et al. | Synthesis and microwave absorption characterization of SiO 2 coated Fe 3 O 4–MWCNT composites | |
| Hossain et al. | Synthesis, structural investigation, dielectric and magnetic properties of Zn 2+-doped cobalt ferrite by the sol–gel technique | |
| CN108865062B (en) | Electromagnetic wave absorbent and preparation method thereof | |
| Lou et al. | Ba 1− x La x Fe 12 O 19 (x= 0.0, 0.2, 0.4, 0.6) hollow microspheres: material parameters, magnetic and microwave absorbing properties | |
| Zhu et al. | Electromagnetic interference shielding polymer composites with magnetic and conductive FeCo/reduced graphene oxide 3D networks | |
| Li et al. | Magnetic and electromagnetic properties of composites of iron oxide and Co–B alloy prepared by chemical reduction | |
| JPH0527059A (en) | Composite body for radio wave absorption | |
| Rosdi et al. | Synthesis and characterization of Mg–Ti substituted barium hexaferrite (BaMg 0.6 Ti 0.6 Fe 10.8 O 19) derived from millscale waste for microwave application | |
| JP4017032B2 (en) | Magnetic film and method for forming the same | |
| Idris et al. | Electromagnetic wave reduction of multiwalled carbon nanotubes (MWCNT) mixed nanometer CoFe2O4 at higher frequency range | |
| JPS6312198A (en) | Electric wave absorbing electromagnetic shielding member | |
| Shafiee et al. | Effect of microstructural evolution from nano to micron grain size regime towards structural, magnetic, electrical and microwave properties of gadolinium iron garnet (Gd 3 Fe 5 O 12) | |
| JPH0527060A (en) | Composite member for radio wave absorption | |
| ŞAHIN et al. | Characterization, production and microwave absorbing properties of polyaniline-NiFe2O4: Tb composites | |
| JP2000068117A (en) | Electromagnetic wave absorbent and its manufacture | |
| JP2007088121A (en) | Composite magnetic film and its manufacturing method | |
| JPH04213803A (en) | Radio wave absorbing material | |
| Balla et al. | Co-Ni-Zn ferrites fabricated by spark plasma sintering | |
| TW495772B (en) | Soft magnetic alloy powder for electromagnetic wave absorbing sheet, electromagnetic wave absorbing sheet, and method for manufacturing them | |
| JPH05335776A (en) | Dielectric compound material | |
| Park et al. | Preparation and characteristics of a magnetic–dielectric (Fe3O4/BaTiO3) composite by ferrite plating with ultrasound irradiation | |
| EP4293690A1 (en) | Magnetic composite |