JPH05335775A - Lamination type electric wave absorber - Google Patents
Lamination type electric wave absorberInfo
- Publication number
- JPH05335775A JPH05335775A JP4137190A JP13719092A JPH05335775A JP H05335775 A JPH05335775 A JP H05335775A JP 4137190 A JP4137190 A JP 4137190A JP 13719092 A JP13719092 A JP 13719092A JP H05335775 A JPH05335775 A JP H05335775A
- Authority
- JP
- Japan
- Prior art keywords
- wave absorber
- electric wave
- magnetic
- electromagnetic wave
- lamination type
- 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.)
- Granted
Links
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は、電波暗室等に使用さ
れる電波吸収体に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic wave absorber used in an anechoic chamber or the like.
【０００２】[0002]
【従来の技術】ＩＣ回路から放射される電波のレベル計
測やＩＣ回路の妨害電波のレベル計測などのためには雑
音電波のない屋外試験場が必要となるが、雑音電波のな
い屋外試験場は得難く、また在ったにしても多くは辺鄙
で不便な場所に在る。2. Description of the Related Art An outdoor test site without noise radio waves is necessary for measuring the level of radio waves emitted from an IC circuit or the level of interfering radio waves of an IC circuit, but it is difficult to obtain an outdoor test site without noise radio waves. However, many are in remote and inconvenient places even if they were there.
【０００３】そこで、雑音電波のない屋外試験場の代わ
りに電波暗室が利用されるようになった。電波暗室は屋
外試験場と等価な環境であることが必要であり、従って
外部からの電波を遮蔽すると共に、電波暗室内で発生し
た電波が電波暗室内の壁で反射されないことが必要とな
る。このため、電波暗室を構成する壁の材料としては良
好な電波吸収体であることが要求される。Therefore, an anechoic chamber has come to be used instead of an outdoor test site where there is no noise radio wave. The anechoic chamber needs to be in an environment equivalent to an outdoor test site, and therefore it is necessary to shield radio waves from the outside and prevent the radio waves generated in the anechoic chamber from being reflected by the wall in the anechoic chamber. Therefore, a good electromagnetic wave absorber is required as the material of the wall forming the anechoic chamber.
【０００４】従来、電波吸収体としては、フェライト焼
結体単体では広帯域周波数に亘って電波吸収特性を得る
のが難しいことから、フェライト焼結体と誘電体とを積
層することにより、電波暗室に必要な反射損失、すなわ
ち５０ＭＨｚ〜８００ＭＨｚで２０ｄＢ以上の反射損失
を得ている。この反射損失は、換言すれば電波吸収体に
おける電波の減衰量である。Conventionally, as a radio wave absorber, it is difficult to obtain a radio wave absorption characteristic over a wide frequency band with a ferrite sintered body alone. Therefore, by stacking a ferrite sintered body and a dielectric material, a radio wave anechoic chamber is provided. The required reflection loss, that is, a reflection loss of 20 dB or more at 50 MHz to 800 MHz is obtained. This reflection loss is, in other words, the amount of attenuation of radio waves in the radio wave absorber.
【０００５】従来の電波吸収体の減衰特性の一例を図３
に示す。これは、特開平２−３５７９７号公報に記載さ
れたもので、電波吸収体としてはフェライトとコンクリ
ートとを積層したものを使用しており、図３に示す特性
はフェライトの厚みが６ｍｍ、コンクリートの厚みが２
０ｍｍの場合であり、縦軸は減衰量をデシベル（ｄＢ）
で示し、横軸は周波数をメガヘルツ（ＭＨｚ）で示す。
図３から分かるように、この電波吸収体における減衰量
は５０ＭＨｚ〜８００ＭＨｚで２０ｄＢ以上である。An example of attenuation characteristics of a conventional electromagnetic wave absorber is shown in FIG.
Shown in. This is described in Japanese Patent Application Laid-Open No. 2-35797, and as the electromagnetic wave absorber, a laminate of ferrite and concrete is used. The characteristics shown in FIG. 3 are as follows: Thickness is 2
It is the case of 0 mm, and the vertical axis shows the attenuation amount in decibel (dB).
And the horizontal axis represents frequency in megahertz (MHz).
As can be seen from FIG. 3, the attenuation amount in this radio wave absorber is 20 dB or more at 50 MHz to 800 MHz.
【０００６】図４は従来の電波吸収体の減衰特性の他の
例を示すグラフである。これは、特開平１−１３８７９
９号公報に記載されたもので、電波吸収体としてはニッ
ケル亜鉛系フェライト（ソフトフェライト）とバリウム
系フェライト（永久磁石）とを積層したものを使用して
おり、図４に示す特性はソフトフェライトの厚みが４ｍ
ｍ、永久磁石の厚みが２ｍｍの場合である。FIG. 4 is a graph showing another example of the attenuation characteristic of the conventional radio wave absorber. This is disclosed in JP-A-1-13879.
The electromagnetic wave absorber used is a laminate of nickel-zinc ferrite (soft ferrite) and barium ferrite (permanent magnet), and the characteristics shown in FIG. 4 are soft ferrites. Is 4m thick
m, and the thickness of the permanent magnet is 2 mm.
【０００７】この電波吸収体の厚みは６ｍｍであり、十
分に薄いが、図４から分かるように減衰量は１５０ＭＨ
ｚ〜４６０ＭＨｚで２０ｄＢ以上であり、このような減
衰特性では電波暗室には使用できない。The thickness of this electromagnetic wave absorber is 6 mm, which is sufficiently thin, but the attenuation is 150 MH as can be seen from FIG.
It is 20 dB or more at z to 460 MHz, and cannot be used in an anechoic chamber with such attenuation characteristics.
【０００８】また、実開昭６０−４８２９４号公報に複
数の誘電体から成る電波吸収体が示されているが、複数
の誘電体を用いて低周波から電波吸収特性の優れた電波
吸収体を作ろうとする場合、波長の約４分の１の厚さ、
たとえば６０ＭＨｚであれば約１．２５ｍの厚さが必要
であり、電波暗室には厚過ぎて容積上の効率が悪く、ま
た運搬性、施工性も悪い。[0008] Further, Japanese Utility Model Laid-Open No. 60-48294 discloses a radio wave absorber composed of a plurality of dielectrics. A radio wave absorber excellent in radio wave absorption characteristics from low frequencies is obtained by using a plurality of dielectrics. If you try to make it, the thickness is about 1/4 wavelength,
For example, 60 MHz requires a thickness of about 1.25 m, which is too thick for an anechoic chamber, resulting in poor volumetric efficiency and poor transportability and workability.
【０００９】[0009]
【発明が解決しようとする課題】上述した従来の電波吸
収体の中では、特開平２−３５７９７号公報記載の積層
型電波吸収体が最も優れているが、電波吸収体の厚みが
金属板を除いて２６ｍｍであり、依然として厚く、その
厚さと重みのため、運搬性、施工性において難点があ
り、より薄い積層型電波吸収体の出現が要請されてい
た。Among the above-mentioned conventional electromagnetic wave absorbers, the laminated electromagnetic wave absorber described in Japanese Patent Laid-Open No. 2-35797 is the most excellent, but the electromagnetic wave absorber has a thickness of a metal plate. The thickness is 26 mm except for it, and it is still thick. Due to its thickness and weight, there are problems in transportability and workability, and the emergence of a thinner laminated wave absorber has been demanded.
【００１０】この発明は、上記事情を考慮してなされた
ものであり、その目的とするところは、減衰特性の優れ
た薄い積層型電波吸収体を提供することにある。The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a thin laminated electromagnetic wave absorber having excellent attenuation characteristics.
【００１１】[0011]
【課題を解決するための手段】上記課題を解決するた
め、この発明は、ゴムまたは樹脂に磁性体粉を混入させ
た磁性複合体とフェライト焼結体とを積層するようにし
た。In order to solve the above-mentioned problems, according to the present invention, a magnetic composite obtained by mixing magnetic powder in rubber or resin and a ferrite sintered body are laminated.
【００１２】[0012]
【作用】この発明による積層型電波吸収体は、ゴムまた
は樹脂に磁性体粉を混入させた磁性複合体とフェライト
焼結体とを積層したことにより、磁性複合体の誘電率と
透磁率とで大きな減衰量を広帯域周波数に亘って得るこ
とができ、電波吸収体をより薄いものとすることができ
る。In the laminated type electromagnetic wave absorber according to the present invention, the dielectric constant and the magnetic permeability of the magnetic composite are obtained by laminating the magnetic composite in which magnetic powder is mixed in rubber or resin and the ferrite sintered body. A large amount of attenuation can be obtained over a wide band frequency, and the radio wave absorber can be made thinner.
【００１３】[0013]
【実施例】以下、この発明による積層型電波吸収体の一
実施例について図面を用いて説明する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the laminated wave absorber according to the present invention will be described below with reference to the drawings.
【００１４】図１は、この発明の一実施例を示す断面図
である。同図に示す積層型電波吸収体は、金属板１、磁
性複合材料から成る磁性複合体の層（以下、「磁性複合
体層」という）２およびニッケル亜鉛系フェライト焼結
体の層（以下、「フェライト層」という）３から成る。FIG. 1 is a sectional view showing an embodiment of the present invention. The laminated type electromagnetic wave absorber shown in FIG. 1 includes a metal plate 1, a magnetic composite layer (hereinafter, referred to as “magnetic composite layer”) 2 made of a magnetic composite material, and a nickel-zinc ferrite sintered body layer (hereinafter, referred to as “magnetic composite layer”). (Referred to as "ferrite layer") 3.
【００１５】磁性複合体層２は、例えばゴムにカーボニ
ル鉄粉を８０〜９０重量％混入させたものであり、５〜
２０の比誘電率と１０〜２０の比透磁率とを持ち、磁性
体の性質のみならず誘電体の性質も有する。この両者の
性質を兼ね備えたことにより、磁性複合体層２は大きな
電波減衰量を有する。The magnetic composite layer 2 is made of, for example, rubber mixed with 80 to 90% by weight of carbonyl iron powder.
It has a relative permittivity of 20 and a relative magnetic permeability of 10 to 20, and has not only the properties of a magnetic substance but also the properties of a dielectric substance. By having both of these properties, the magnetic composite layer 2 has a large amount of radio wave attenuation.
【００１６】図１において、磁性複合体層２の厚みは３
ｍｍ、フェライト層３の厚みは５．５ｍｍであり、層２
と層３との合計厚みは８．５ｍｍである。これは、前述
の特開平２−３５７９７号公報記載の積層型電波吸収体
の厚み２６ｍｍよりも遥かに薄く、運搬性、施工性等に
おいて優れている。なお、金属板１の厚みは従来と同程
度でよく、１〜２ｍｍあれば十分である。In FIG. 1, the thickness of the magnetic composite layer 2 is 3
mm, the thickness of the ferrite layer 3 is 5.5 mm, and the layer 2
And layer 3 has a total thickness of 8.5 mm. This is much thinner than the thickness 26 mm of the laminated type electromagnetic wave absorber described in JP-A-2-35797, and is excellent in transportability and workability. The thickness of the metal plate 1 may be the same as that of the conventional one, and 1-2 mm is sufficient.
【００１７】図２は、図１の積層型電波吸収体の減衰特
性を示すグラフであり、縦軸は減衰量をデシベル（ｄ
Ｂ）で示し、横軸は周波数をメガヘルツ（ＭＨｚ）で示
す。図２から分かるように、この実施例に係る電波吸収
体の減衰量は５０ＭＨｚ〜８５０ＭＨｚに亘って２０ｄ
Ｂ以上であり、特開平２−３５７９７号公報記載の積層
型電波吸収体よりも優れた広帯域性を有する。FIG. 2 is a graph showing the attenuation characteristic of the laminated electromagnetic wave absorber of FIG. 1, in which the vertical axis represents the attenuation amount in decibels (d).
B), and the horizontal axis represents frequency in megahertz (MHz). As can be seen from FIG. 2, the attenuation amount of the radio wave absorber according to this example is 20 d over 50 MHz to 850 MHz.
It is B or more and has a wider band property than the laminated type electromagnetic wave absorber described in JP-A-2-35797.
【００１８】なお、上記実施例では、ゴムにカーボニル
鉄粉を混入した場合を示したが、これに限らず、ゴムに
フェライト粉を混入させても、またゴムに磁性体粉およ
び誘電体粉を混入させてもよく、さらに、ゴムでなく樹
脂に各材料を混入させるようにしてもよく、上記実施例
と同様の効果を奏する。In the above embodiment, the case where carbonyl iron powder is mixed in the rubber is shown, but the present invention is not limited to this, and the ferrite powder may be mixed in the rubber, or the magnetic powder and the dielectric powder may be mixed in the rubber. The materials may be mixed, and further, each material may be mixed in the resin instead of the rubber, and the same effect as that of the above-described embodiment is obtained.
【００１９】[0019]
【発明の効果】以上説明したように、この発明によれ
ば、磁性複合体により従来よりも大きな減衰特性を得る
ことができるので、電波の減衰特性を広帯域に維持しな
がら、積層型電波吸収体の厚みを従来よりも遥かに薄い
ものとすることができ、運搬性、加工性に優れた電波吸
収体を得ることができる。As described above, according to the present invention, since the magnetic composite can obtain a larger attenuation characteristic than the conventional one, the laminated type electromagnetic wave absorber can be maintained while maintaining the electromagnetic wave attenuation characteristic in a wide band. The thickness of the electromagnetic wave absorber can be made far thinner than the conventional one, and a radio wave absorber excellent in transportability and workability can be obtained.
【図１】この発明による積層型電波吸収体の一実施例を
示す断面図である。FIG. 1 is a sectional view showing an embodiment of a laminated type electromagnetic wave absorber according to the present invention.
【図２】（ａ），（ｂ）は、図１の積層型電波吸収体の
減衰特性を、磁性複合体層の厚さが異なる比較例の減衰
特性とともに示すグラフである。2 (a) and 2 (b) are graphs showing the attenuation characteristics of the laminated type electromagnetic wave absorber of FIG. 1 together with the attenuation characteristics of a comparative example in which the thickness of the magnetic composite layer is different.
【図３】従来の積層型電波吸収体の一例の減衰特性を示
すグラフである。FIG. 3 is a graph showing an attenuation characteristic of an example of a conventional laminated type electromagnetic wave absorber.
【図４】従来の積層型電波吸収体の他の例の減衰特性を
示すグラフである。FIG. 4 is a graph showing attenuation characteristics of another example of the conventional laminated type electromagnetic wave absorber.
１ 金属板 ２ 磁性複合体層 ３ フェライト層 1 metal plate 2 magnetic composite layer 3 ferrite layer
Claims (2)
磁性複合体とフェライト焼結体とを積層したことを特徴
とする積層型電波吸収体。1. A laminate type electromagnetic wave absorber, comprising a magnetic composite material obtained by mixing magnetic powder in rubber or resin, and a ferrite sintered body.
て、 磁性複合体はゴムにカーボニル鉄粉を８０〜９０重量％
混入させたものであることを特徴とする積層型電波吸収
体。2. The laminated type electromagnetic wave absorber according to claim 1, wherein the magnetic composite has 80 to 90% by weight of carbonyl iron powder in rubber.
A laminated type electromagnetic wave absorber characterized by being mixed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4137190A JP2663409B2 (en) | 1992-05-28 | 1992-05-28 | Laminated wave absorber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4137190A JP2663409B2 (en) | 1992-05-28 | 1992-05-28 | Laminated wave absorber |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05335775A true JPH05335775A (en) | 1993-12-17 |
| JP2663409B2 JP2663409B2 (en) | 1997-10-15 |
Family
ID=15192907
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4137190A Expired - Fee Related JP2663409B2 (en) | 1992-05-28 | 1992-05-28 | Laminated wave absorber |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2663409B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007129526A1 (en) * | 2006-05-08 | 2007-11-15 | Ibiden Co., Ltd. | Inductor and electric power source using same |
| JP2009255368A (en) * | 2008-04-16 | 2009-11-05 | Panasonic Corp | Composite magnetic material and radio communication apparatus equipped with it |
| JP2013209874A (en) * | 2012-02-28 | 2013-10-10 | Nichirei Magnet Kk | Magnetic layer of building member |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS555720A (en) * | 1978-06-28 | 1980-01-16 | Mitsubishi Gas Chem Co Inc | Storing method for vegetable and fruit |
| JPS556320A (en) * | 1978-06-27 | 1980-01-17 | Ritsuo Hasumi | Spectral module |
| JPS5931714A (en) * | 1982-06-25 | 1984-02-20 | ナシヨナル・スタ−チ・アンド・ケミカル・コ−ポレイシヨン | Contraceptive composition |
| JPS60146398U (en) * | 1984-03-07 | 1985-09-28 | ティーディーケイ株式会社 | shield case |
| JPS6197998A (en) * | 1984-10-19 | 1986-05-16 | ティーディーケイ株式会社 | Electromagnetic shield material |
| JPS6289747A (en) * | 1985-06-15 | 1987-04-24 | Tdk Corp | Electrical radiation absorbing material |
| JPS6341758U (en) * | 1986-09-04 | 1988-03-18 | ||
| JPH0295293U (en) * | 1989-01-18 | 1990-07-30 |
-
1992
- 1992-05-28 JP JP4137190A patent/JP2663409B2/en not_active Expired - Fee Related
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS556320A (en) * | 1978-06-27 | 1980-01-17 | Ritsuo Hasumi | Spectral module |
| JPS555720A (en) * | 1978-06-28 | 1980-01-16 | Mitsubishi Gas Chem Co Inc | Storing method for vegetable and fruit |
| JPS5931714A (en) * | 1982-06-25 | 1984-02-20 | ナシヨナル・スタ−チ・アンド・ケミカル・コ−ポレイシヨン | Contraceptive composition |
| JPS60146398U (en) * | 1984-03-07 | 1985-09-28 | ティーディーケイ株式会社 | shield case |
| JPS6197998A (en) * | 1984-10-19 | 1986-05-16 | ティーディーケイ株式会社 | Electromagnetic shield material |
| JPS6289747A (en) * | 1985-06-15 | 1987-04-24 | Tdk Corp | Electrical radiation absorbing material |
| JPS6341758U (en) * | 1986-09-04 | 1988-03-18 | ||
| JPH0295293U (en) * | 1989-01-18 | 1990-07-30 |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007129526A1 (en) * | 2006-05-08 | 2007-11-15 | Ibiden Co., Ltd. | Inductor and electric power source using same |
| JPWO2007129526A1 (en) * | 2006-05-08 | 2009-09-17 | イビデン株式会社 | Inductor and power supply circuit using the same |
| KR100973447B1 (en) * | 2006-05-08 | 2010-08-02 | 이비덴 가부시키가이샤 | Inductor and electric power source using same |
| US7812702B2 (en) | 2006-05-08 | 2010-10-12 | Ibiden Co., Ltd. | Inductor and electric power supply using it |
| US7843302B2 (en) | 2006-05-08 | 2010-11-30 | Ibiden Co., Ltd. | Inductor and electric power supply using it |
| US7855626B2 (en) | 2006-05-08 | 2010-12-21 | Ibiden Co., Ltd. | Inductor and electric power supply using it |
| US7868728B2 (en) | 2006-05-08 | 2011-01-11 | Ibiden Co., Ltd. | Inductor and electric power supply using it |
| US8207811B2 (en) | 2006-05-08 | 2012-06-26 | Ibiden Co., Ltd. | Inductor and electric power supply using it |
| JP2009255368A (en) * | 2008-04-16 | 2009-11-05 | Panasonic Corp | Composite magnetic material and radio communication apparatus equipped with it |
| JP2013209874A (en) * | 2012-02-28 | 2013-10-10 | Nichirei Magnet Kk | Magnetic layer of building member |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2663409B2 (en) | 1997-10-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |