JP2000138492A - Electromagnetic wave absorber - Google Patents
Electromagnetic wave absorberInfo
- Publication number
- JP2000138492A JP2000138492A JP10312480A JP31248098A JP2000138492A JP 2000138492 A JP2000138492 A JP 2000138492A JP 10312480 A JP10312480 A JP 10312480A JP 31248098 A JP31248098 A JP 31248098A JP 2000138492 A JP2000138492 A JP 2000138492A
- Authority
- JP
- Japan
- Prior art keywords
- electromagnetic wave
- soft magnetic
- powder
- grain size
- wave absorber
- 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.)
- Withdrawn
Links
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、電磁波とくに数Ｇ
Ｈｚオーダーの高い周波数領域の電磁波の遮蔽および吸
収のために使用する、電磁波吸収体の改良に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic wave,
The present invention relates to an improvement in an electromagnetic wave absorber used for shielding and absorbing electromagnetic waves in a high frequency range on the order of Hz.
【０００２】[0002]
【従来の技術】各種の電子機器に関して、外部への電磁
波の放出を防ぎ、また外部からの電磁波を吸収し、相互
の干渉を防止するため、種々の電磁波吸収材料が開発さ
れている。 それらの多くは、パーマロイ、センダス
ト、Ｆｅ−Ｃｒ−Ａｌ合金などの軟磁性金属の粉末を、
ゴムまたは合成樹脂のマトリクス中に分散させ、適宜の
形状に成形してなるものである。 形状は、使用に便利
なシートの形をとることが多い。2. Description of the Related Art With respect to various electronic devices, various electromagnetic wave absorbing materials have been developed in order to prevent emission of electromagnetic waves to the outside, absorb electromagnetic waves from the outside, and prevent mutual interference. Many of them use soft magnetic metal powders such as permalloy, sendust, and Fe-Cr-Al alloys.
It is formed by dispersing in a rubber or synthetic resin matrix and molding into an appropriate shape. The shape often takes the form of a sheet that is convenient to use.
【０００３】電磁波を吸収する能力は、通常、ネットワ
ークアナライザーを使用した試験により測定される、リ
ターンロス（単位ｄＢ）の値で評価される。 リターン
ロスを大きくするためには、原理的にいって、電磁波の
経路における軟磁性金属の存在量を大きくすることが必
要である。[0003] The ability to absorb electromagnetic waves is usually evaluated by the value of return loss (unit: dB) measured by a test using a network analyzer. In order to increase the return loss, it is necessary in principle to increase the abundance of the soft magnetic metal in the path of the electromagnetic wave.
【０００４】一方、リターンロスのピーク、すなわちそ
の電磁波吸収体がもっともよくその吸収能を発揮する周
波数領域は、使用した軟磁性金属の種類、粉末の形状、
マトリクスへの充填量など、多く因子によって決定され
る。 シート状の電磁波吸収体において、大きなリター
ンロスを得ようとすると、必然的にシートを厚くせざる
を得ないが、許容できるシート厚には、それぞれの電子
機器によって実用上の制限がある。 制限内であって
も、シート厚を厚くすると、リターンロスのピークが低
周波数側にシフトしてしまうという問題がある。 これ
は、より高い周波数領域を利用しようという動向からみ
て好ましくない。On the other hand, the peak of the return loss, that is, the frequency region in which the electromagnetic wave absorber exhibits the best absorption ability, depends on the type of soft magnetic metal used, the shape of the powder,
It is determined by many factors, such as the amount of matrix filling. In order to obtain a large return loss in the sheet-like electromagnetic wave absorber, the sheet is inevitably thickened. However, the allowable sheet thickness has practical limitations depending on each electronic device. Even within the limit, when the sheet thickness is increased, there is a problem that the peak of the return loss shifts to the lower frequency side. This is undesirable in view of the trend to use higher frequency regions.
【０００５】[0005]
【発明が解決しようとする課題】本発明の目的は、同じ
厚さで従来品より高い電磁波吸収能を発揮し、従って実
用上一般に許容できる厚さで十分な電磁波吸収能を有す
る電磁波吸収体であって、しかも厚さの増大がリターン
ロスのピークをシフトさせることのないものを提供する
ことにある。SUMMARY OF THE INVENTION An object of the present invention is to provide an electromagnetic wave absorber which exhibits a higher electromagnetic wave absorbing power than conventional products at the same thickness, and which has a sufficient electromagnetic wave absorbing power at a thickness which is generally acceptable in practical use. An object of the present invention is to provide a semiconductor device in which the increase in thickness does not shift the peak of return loss.
【０００６】[0006]
【課題を解決するための手段】本発明の電磁波吸収体
は、軟磁性金属の粒径４ミクロン以下の微粉末を、ゴム
または合成樹脂のマトリクス中に分散させてなる。The electromagnetic wave absorber according to the present invention is obtained by dispersing a fine powder of a soft magnetic metal having a particle size of 4 μm or less in a rubber or synthetic resin matrix.
【０００７】[0007]
【発明の実施の形態】軟磁性金属の微粉末としては、Ｆ
ｅ，Ｎｉ，Ｃｏ，Ｆｅ−Ｃｒ−Ａｌ，Ｆｅ−Ｓｉ−Ｃ
ｒ，Ｆｅ−Ｓｉ−Ａｌまたはパーマロイの微粉末が好適
である。 ４ミクロン以下の微粉末は、金属化合物たと
えばカルボニル鉄の還元分解によれば、容易に入手する
ことができる。 カルボニル鉄から得た鉄の粉末は、球
状をしていてマトリクス材料との混合が容易である。
微細な粉末の取得は、気流による分級により実施でき
る。 粒径の測定は、レーザー光により、容易に行なえ
る。BEST MODE FOR CARRYING OUT THE INVENTION As a soft magnetic metal fine powder, F
e, Ni, Co, Fe-Cr-Al, Fe-Si-C
Fine powder of r, Fe-Si-Al or permalloy is preferred. Fine powders of 4 microns or less can be easily obtained by reductive decomposition of metal compounds such as carbonyl iron. Iron powder obtained from carbonyl iron is spherical and can be easily mixed with the matrix material.
Acquisition of fine powder can be performed by classification using an airflow. The measurement of the particle size can be easily performed by a laser beam.
【０００８】マトリクス材料としては、任意のゴムまた
は合成樹脂が使用できるが、出願人が提案してきた電磁
波吸収体の多くに使用されている、塩素化ポリエチレン
ゴムが最適である。Although any rubber or synthetic resin can be used as the matrix material, chlorinated polyethylene rubber, which is used in many of the electromagnetic wave absorbers proposed by the applicant, is most suitable.
【０００９】電磁波吸収体の開発の過程で発明者らが知
ったところによれば、軟磁性体粉末をマトリクス中に分
散させたタイプの電磁波吸収体においては、粉末の粒径
が小さくなると、誘電率ε'、ε''、および透磁率μ'、
μ''のうち、ε'およびε''は若干減少し、μ'および
μ''はやや大きくなる。 これらの作用が影響し合っ
て、リターンロスのピークの位置は変わらないが、値が大きく
なる、つまり減衰量が大きくなるわけである。According to what the inventors have learned during the development of the electromagnetic wave absorber, in the electromagnetic wave absorber of the type in which the soft magnetic material powder is dispersed in the matrix, when the particle size of the powder becomes small, the dielectric material becomes insulative. Ε ′, ε ″, and permeability μ ′,
Of μ ″, ε ′ and ε ″ slightly decrease, and μ ′ and μ ″ slightly increase. These effects affect each other, and the position of the peak of the return loss does not change, but the value increases, that is, the attenuation increases.
【００１０】[0010]
【参考例】軟磁性金属の粉末として、Ｆｅ−Ｃｒ−Ａｌ
合金の平均粒度１８ミクロンの粉末を使用し、塩素化ポ
リエチレンゴムと、容量比にして５５：４５の割合で配
合して混練し、押出しおよびカレンダリングにより、厚
さ０．５ミリおよび１．０ミリのシートを製造した。
これらのシートの電磁波吸収能を０．１〜１０ＧＨｚの
周波数領域において測定し、図１に示すリターンロスの
周波数特性曲線を得た。 図１から、シートの厚さの増
大に伴ってリターンロスが増加するが、一方でそのピー
クが低周波側に移動している（４〜５ＭＨｚから２ＭＨ
ｚへ）ことがわかる。[Reference Example] Fe-Cr-Al as soft magnetic metal powder
A powder having an average particle size of 18 microns was mixed with chlorinated polyethylene rubber at a volume ratio of 55:45, kneaded, extruded and calendered to a thickness of 0.5 mm and 1.0 mm. Millimeter sheets were produced.
The electromagnetic wave absorbing capacity of these sheets was measured in a frequency range of 0.1 to 10 GHz, and a frequency characteristic curve of return loss shown in FIG. 1 was obtained. From FIG. 1, the return loss increases as the thickness of the sheet increases, while its peak moves to the low frequency side (from 4 to 5 MHz to 2 MHz).
z).
【００１１】[0011]
【実施例１および比較例】下記２種類の軟磁性金属か
ら、粒径の異なる粉末各３種類を用意した： 軟磁性金属 平均粒径 （ミクロン） カルボニル鉄 Ｄ50 ９．７ ３．４*1 １．６*2 Ｆｅ−Ｃｒ−Ａｌ Ｄ50 ２２．１ １４．０ ７．６ ＊１および＊２が本発明の実施例で、残りは比較例。Example 1 and Comparative Example Three kinds of powders having different particle sizes were prepared from the following two types of soft magnetic metals: soft magnetic metal Average particle size (micron) carbonyl iron D 50 9.7 3.4 * 1 1.6 * example of 2 Fe-Cr-Al D 50 22.1 14.0 7.6 * 1 and * 2 is the invention, with the remainder Comparative example.
【００１２】これらの粉末と塩素化ポリエチレンとを、
容量比で５５：４５の割合で配合し、参考例と同様に混
練および押出しを行なって、いずれも厚さ１．０ミリの
電磁波吸収シートを製造した。These powders and chlorinated polyethylene are
They were blended at a volume ratio of 55:45 and kneaded and extruded in the same manner as in the Reference Example to produce an electromagnetic wave absorbing sheet having a thickness of 1.0 mm in each case.
【００１３】それらのシートについて、ε'、μ'および
μ''を、周波数５ＧＨｚおよび８ＧＨｚにおいて測定
し、図２、図３および図４に示すグラフを得た。 これ
らのグラフから、前述のように、粒径が小さくなると
ε'が小さくなり、μ'およびμ''は大きくなることが分
かる。 とくに、μ'は粒径４ミクロン以下で急激に増
大しており、これがε'の減少との相互作用で、リター
ンロスのピークが低周波側にシフトすることを抑制して
いるものと解される。 本発明で平均粒径４ミクロン以
下の微細粉末を使用するのは、この事実と、図５および
図６にみるように、微細な粉末ほど電磁波吸収能が高い
吸収体を与えるという事実に基づいている。For these sheets, ε ′, μ ′ and μ ″ were measured at frequencies of 5 GHz and 8 GHz, and the graphs shown in FIGS. 2, 3 and 4 were obtained. From these graphs, it can be seen that, as described above, the smaller the particle size, the smaller ε ′ and the larger μ ′ and μ ″. In particular, it is understood that μ ′ increases rapidly when the particle diameter is 4 μm or less, and this is an interaction with the decrease in ε ′, which suppresses the shift of the return loss peak to the lower frequency side. You. The use of fine powder having an average particle size of 4 microns or less in the present invention is based on this fact and the fact that, as shown in FIGS. 5 and 6, a finer powder gives an absorber having higher electromagnetic wave absorbing ability. I have.
【００１４】カルボニル鉄の粉末を使用した３種の電磁
波吸収シートについて、リターンロスの周波数特性を測
定した結果は、図５に示すとおりである。 このグラフ
は、同じシート厚さで、その中に分散させた軟磁性金属
の粉末の粒径を小さくすれば、リターンロスが大きくな
る、つまり電磁波吸収能が高まるということを示してい
る。FIG. 5 shows the results of measuring the return loss frequency characteristics of three types of electromagnetic wave absorbing sheets using carbonyl iron powder. This graph shows that if the particle size of the soft magnetic metal powder dispersed in the same sheet thickness is reduced, the return loss increases, that is, the electromagnetic wave absorbing ability increases.
【００１５】[0015]
【実施例２】実施例１で使用した２種類のカルボニル鉄
の粉末を、同じ塩素化ポリエチレンに、容量比にして４
０：６０の割合で配合した。 この配合物を加工して、
やはり厚さ１．０ミリの電磁波に示す。 このデータ
は、同じ分散量であっても、より微細な粉末（平均粒径
３．４ミクロンに対し１．６ミクロン）の方が、より高
い電磁波吸収能を発揮することを明らかに示している。Example 2 The two kinds of carbonyl iron powders used in Example 1 were mixed with the same chlorinated polyethylene in a volume ratio of 4%.
It was blended at a ratio of 0:60. Processing this compound,
This is also shown for an electromagnetic wave having a thickness of 1.0 mm. This data clearly shows that, at the same dispersion, a finer powder (1.6 micron versus 3.4 micron average particle size) exhibits higher electromagnetic wave absorption. .
【００１６】[0016]
【図１】 従来の電磁波吸収シートにおいて、シートの
厚さを増すと、吸収できる電磁波の周波数のピークが低
周波側へシフトする様子を示す、リターンロスの周波数
依存曲線。FIG. 1 is a frequency diagram of a return loss frequency curve showing that a peak of a frequency of an electromagnetic wave that can be absorbed shifts to a lower frequency side when the thickness of the sheet is increased in a conventional electromagnetic wave absorbing sheet.
【図２】 本発明の実施例および比較例のデータであっ
て、試作した電磁波吸収シートのε'と軟磁性金属の粒
径との関係を示すグラフ。FIG. 2 is a graph showing data of Examples and Comparative Examples of the present invention, showing a relationship between ε ′ of a prototype electromagnetic wave absorbing sheet and a particle size of a soft magnetic metal.
【図３】 本発明の実施例および比較例のデータであっ
て、試作した電磁波吸収シートのμ'と軟磁性金属の粒
径との関係を示すグラフ。FIG. 3 is a graph showing data of examples and comparative examples of the present invention, showing a relationship between μ ′ of a prototype electromagnetic wave absorbing sheet and a particle size of a soft magnetic metal.
【図４】 本発明の実施例および比較例のデータであっ
て、試作した電磁波吸収シートのμ''と軟磁性金属の粒
径との関係を示すグラフ。FIG. 4 is a graph showing data of Examples and Comparative Examples of the present invention, showing a relationship between μ ″ of a prototype electromagnetic wave absorbing sheet and a particle size of a soft magnetic metal.
【図５】 本発明の実施例１のデータであって、試作し
た電磁波吸収シートのリターンロスと周波数との関係を
示すグラフ。FIG. 5 is a graph showing data of Example 1 of the present invention, showing a relationship between return loss and frequency of a prototype electromagnetic wave absorbing sheet.
【図６】 本発明の実施例２のデータであって、試作し
た電磁波吸収シートのリターンロスと周波数との関係を
示すグラフ。FIG. 6 is a graph showing data of Example 2 of the present invention, showing a relationship between return loss and frequency of a prototype electromagnetic wave absorbing sheet.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 筒井 和久 愛知県東海市加木屋町南鹿持18番地 Ｆターム(参考） 5E040 AA11 AA14 AA19 BB06 CA13 5E041 AA04 AA07 AA11 AA14 AA17 AA19 BB04 CA06 5E321 BB32 BB44 BB53 GG05 GG07 GG11 5J020 BD02 EA02 EA10 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kazuhisa Tsutsui 18-term, F-term (reference) 5E040 AA11 AA14 AA19 BB06 CA13 5E041 AA04 AA07 AA11 AA14 AA17 AA19 BB04 CA06 5E321 BB53 BB53 GG53 GG11 5J020 BD02 EA02 EA10
Claims (5)
粉末を、ゴムまたは合成樹脂のマトリクス中に分散させ
てなる電磁波吸収体。1. An electromagnetic wave absorber comprising fine powder of a soft magnetic metal having a particle size of 4 μm or less dispersed in a rubber or synthetic resin matrix.
ｉ，Ｃｏ，Ｆｅ−Ｃｒ−Ａｌ，Ｆｅ−Ｓｉ−Ｃｒ，Ｆｅ
−Ｓｉ−Ａｌまたはパーマロイの微粉末を使用した請求
項１の電磁波吸収体。2. A fine powder of a soft magnetic metal comprising Fe, N
i, Co, Fe-Cr-Al, Fe-Si-Cr, Fe
The electromagnetic wave absorber according to claim 1, wherein fine powder of -Si-Al or permalloy is used.
ル鉄の分解により得た球状の鉄粉を使用した請求項２の
請求項１の電磁波吸収体3. The electromagnetic wave absorber according to claim 1, wherein a spherical iron powder obtained by decomposing carbonyl iron is used as the soft magnetic metal fine powder.
チレンゴムを使用した請求項１の電磁波吸収体。4. The electromagnetic wave absorber according to claim 1, wherein a chlorinated polyethylene rubber is used as a matrix material.
１の電磁波吸収体。5. The electromagnetic wave absorber according to claim 1, wherein the electromagnetic wave absorber is formed into a sheet.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10312480A JP2000138492A (en) | 1998-11-02 | 1998-11-02 | Electromagnetic wave absorber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10312480A JP2000138492A (en) | 1998-11-02 | 1998-11-02 | Electromagnetic wave absorber |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2000138492A true JP2000138492A (en) | 2000-05-16 |
Family
ID=18029727
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10312480A Withdrawn JP2000138492A (en) | 1998-11-02 | 1998-11-02 | Electromagnetic wave absorber |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2000138492A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20030013831A (en) * | 2001-08-09 | 2003-02-15 | 주식회사 두람하이테크 | Metal compound resin composition and a sheet for intercepting electromagnetic waves and a method for fabricating the same |
| KR20030023899A (en) * | 2001-09-14 | 2003-03-26 | 김성수 | Thin microwave absorbers used in frequency range of mobile telecommunication |
| JP2009059726A (en) * | 2007-08-29 | 2009-03-19 | Tdk Corp | Radio wave absorber |
| KR101420368B1 (en) * | 2012-04-24 | 2014-07-16 | 두성산업 주식회사 | Conductive contactor for absorbing electromagnetic waves for surface mounting technology |
| CN112533466A (en) * | 2020-12-02 | 2021-03-19 | 中国人民解放***箭军工程大学 | MOFs derived porous carbon coated sheet carbonyl iron composite wave-absorbing material and preparation method thereof |
| CN112689452A (en) * | 2020-12-02 | 2021-04-20 | 中国人民解放***箭军工程大学 | Co/C/carbonyl iron fiber composite wave-absorbing material derived from metal organic framework and preparation method thereof |
| JP7005132B2 (en) | 2016-09-29 | 2022-02-04 | 大同特殊鋼株式会社 | Electromagnetic wave absorption sheet |
-
1998
- 1998-11-02 JP JP10312480A patent/JP2000138492A/en not_active Withdrawn
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20030013831A (en) * | 2001-08-09 | 2003-02-15 | 주식회사 두람하이테크 | Metal compound resin composition and a sheet for intercepting electromagnetic waves and a method for fabricating the same |
| KR20030023899A (en) * | 2001-09-14 | 2003-03-26 | 김성수 | Thin microwave absorbers used in frequency range of mobile telecommunication |
| JP2009059726A (en) * | 2007-08-29 | 2009-03-19 | Tdk Corp | Radio wave absorber |
| KR101420368B1 (en) * | 2012-04-24 | 2014-07-16 | 두성산업 주식회사 | Conductive contactor for absorbing electromagnetic waves for surface mounting technology |
| JP7005132B2 (en) | 2016-09-29 | 2022-02-04 | 大同特殊鋼株式会社 | Electromagnetic wave absorption sheet |
| CN112533466A (en) * | 2020-12-02 | 2021-03-19 | 中国人民解放***箭军工程大学 | MOFs derived porous carbon coated sheet carbonyl iron composite wave-absorbing material and preparation method thereof |
| CN112689452A (en) * | 2020-12-02 | 2021-04-20 | 中国人民解放***箭军工程大学 | Co/C/carbonyl iron fiber composite wave-absorbing material derived from metal organic framework and preparation method thereof |
| CN112689452B (en) * | 2020-12-02 | 2022-07-22 | 中国人民解放***箭军工程大学 | Co/C/carbonyl iron fiber composite wave-absorbing material derived from metal organic framework and preparation method thereof |
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