JPH0992996A - Wave absorber - Google Patents
Wave absorberInfo
- Publication number
- JPH0992996A JPH0992996A JP7246089A JP24608995A JPH0992996A JP H0992996 A JPH0992996 A JP H0992996A JP 7246089 A JP7246089 A JP 7246089A JP 24608995 A JP24608995 A JP 24608995A JP H0992996 A JPH0992996 A JP H0992996A
- Authority
- JP
- Japan
- Prior art keywords
- wave absorber
- dielectric
- radio wave
- phenol resin
- phenolic resin
- 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- Withdrawn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
Landscapes
- Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、例えば、高層ビ
ル、橋梁、高速道路の高架等の建造物の表面における電
波の反射を防止するために、建造物等に取り付ける電波
吸収体に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio wave absorber attached to a building or the like in order to prevent the reflection of radio waves on the surface of the building such as a high-rise building, a bridge, or an elevated highway.
【0002】[0002]
【従来の技術】従来、樹脂中にフェライト粉末やカーボ
ン粉末等を分散させた誘電体の片側に金属薄板を貼着し
てなる電波吸収体が知られているが、誘電体の厚みを実
用的な厚さにした場合、吸収可能な電波の周波数帯域が
数GHzとなり、テレビのゴースト等の防止に有効な1
00〜900MHz程度の周波数の電波を吸収すること
が困難であった。そのため、薄い厚さで100〜900
MHz程度の周波数の電波を吸収することが可能な電波
吸収体が求められている。また、上記の樹脂は一般に可
燃性であるため、建造物等に取り付ける用途の電波吸収
体としては準不燃化することも求められている。2. Description of the Related Art Heretofore, a radio wave absorber has been known in which a thin metal plate is attached to one side of a dielectric material in which ferrite powder, carbon powder, etc. are dispersed in a resin. If the thickness is thick, the frequency band of radio waves that can be absorbed becomes several GHz, which is effective in preventing ghosts on TV.
It has been difficult to absorb radio waves with a frequency of about 00 to 900 MHz. Therefore, a thin thickness of 100-900
There is a demand for a radio wave absorber capable of absorbing a radio wave having a frequency of about MHz. In addition, since the above resins are generally flammable, it is also required to make them semi-inflammable as a radio wave absorber for use in a building or the like.
【0003】一方、テレビ電波等の比較的低い周波数帯
域の電波の吸収材としてはフェライト焼結体が使用され
る場合がある。この場合、厚さも10mm程度で電波の
吸収性能も優れているが、金属の焼結体であるため非常
に重いという欠点があり、その改善が求められている。On the other hand, a ferrite sintered body may be used as an absorber of radio waves in a relatively low frequency band such as television radio waves. In this case, the thickness is about 10 mm and the radio wave absorption performance is excellent, but there is a drawback that it is very heavy because it is a sintered body of metal, and its improvement is required.
【0004】[0004]
【発明が解決しようとする課題】本発明は上記のような
事情に鑑みてなされたものであって、その目的とすると
ころは、薄い厚さで、100〜900MHz程度の周波
数の電波を吸収することが可能な、軽量でかつ準不燃性
の電波吸収体を提供することである。SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and its object is to absorb a radio wave having a thin thickness and a frequency of about 100 to 900 MHz. It is possible to provide a lightweight, quasi-incombustible radio wave absorber that can be manufactured.
【0005】[0005]
【課題を解決するための手段】請求項1に係る発明の電
波吸収体は、フェノール樹脂発泡体中に炭素繊維が分散
されている誘電体と該誘電体の一方の面に貼着される導
電体とからなることを特徴とする。According to a first aspect of the present invention, there is provided a radio wave absorber of a dielectric material in which carbon fibers are dispersed in a phenol resin foam, and a conductive material attached to one surface of the dielectric material. It is characterized by consisting of a body.
【0006】請求項2に係る発明の電波吸収体は、請求
項1記載の電波吸収体において、誘電体中の炭素繊維の
含有率が0.5〜10重量%であることを特徴とする。A radio wave absorber according to a second aspect of the present invention is the radio wave absorber according to the first aspect, characterized in that the content of carbon fiber in the dielectric is 0.5 to 10% by weight.
【0007】請求項3に係る発明の電波吸収体は、請求
項1又は請求項2記載の電波吸収体において、導電体が
金属板であることを特徴とする。A radio wave absorber according to a third aspect of the present invention is the radio wave absorber according to the first or second aspect, wherein the conductor is a metal plate.
【0008】[0008]
【発明の実施の形態】以下、本発明の実施の形態を説明
する。Embodiments of the present invention will be described below.
【0009】図1は本発明の電波吸収体の構成を示す概
略図であり、図1に示すように、本発明の電波吸収体
は、フェノール樹脂発泡体1中に炭素繊維2が分散され
ている誘電体3と該誘電体3の一方の面に貼着される導
電体4とからなっている。このフェノール樹脂発泡体1
はレゾール型フェノール樹脂やノボラック型フェノール
樹脂等のフェノール樹脂に、n−ヘキサン、塩化メチレ
ン、トリクロロメタン、ジニトロペンタメチレンテトラ
ミン等の発泡剤、無機酸、芳香族スルフォン酸、ヘキサ
メチレンテトラミン等の硬化剤を配合したものを、加熱
して発泡硬化させることにより製造することができる。
なお、フェノール樹脂に発泡剤、硬化剤等を配合したも
のはフェノール樹脂発泡材として市販されているので、
この市販のフェノール樹脂発泡材を使用してもよい。FIG. 1 is a schematic view showing the structure of the radio wave absorber of the present invention. As shown in FIG. 1, the radio wave absorber of the present invention has a carbon fiber 2 dispersed in a phenol resin foam 1. It is composed of a dielectric 3 and a conductor 4 attached to one surface of the dielectric 3. This phenol resin foam 1
Is a phenol resin such as a resole type phenol resin or a novolac type phenol resin, a foaming agent such as n-hexane, methylene chloride, trichloromethane or dinitropentamethylenetetramine, a curing agent such as an inorganic acid, an aromatic sulfonic acid or hexamethylenetetramine. It can be manufactured by heating and foaming and curing a mixture of
In addition, since a mixture of a phenol resin with a foaming agent and a curing agent is commercially available as a phenol resin foam material,
This commercially available phenol resin foam material may be used.
【0010】フェノール樹脂は準不燃性であるため、フ
ェノール樹脂発泡体よりなる本発明の電波吸収体は準不
燃材として外壁材としても使用可能である。そしてフェ
ノール樹脂はその誘電率が4〜6と樹脂の中では大きい
ため、電波吸収の効果が高いので、本発明の電波吸収体
は薄型化が図りやすい。さらにフェノール樹脂発泡体の
比重は小さいので本発明の電波吸収体は軽量化が図りや
すい。Since the phenol resin is quasi-incombustible, the radio wave absorber of the present invention made of a phenol resin foam can be used as a quasi-incombustible material as an outer wall material. Since the phenolic resin has a large dielectric constant of 4 to 6 among the resins, it has a high effect of absorbing radio waves, so that the radio wave absorber of the present invention can be easily thinned. Further, since the specific gravity of the phenol resin foam is small, the radio wave absorber of the present invention can be easily reduced in weight.
【0011】本発明の電波吸収体で使用する炭素繊維
は、特に限定するものではないが、直径1〜50μm、
長さ0.1〜2mmのものが望ましい。なぜならば、ア
スペクト比が小さすぎると誘電体の誘電率が大きくなら
ず、電波吸収体の薄型化が図り難くなり、また、繊維が
長くなりすぎるとフェノール樹脂発泡体中への分散が困
難となるからである。そして、電波吸収体を構成する誘
電体中の炭素繊維の含有率については、特に限定するも
のではないが、0.5〜10重量%であることが望まし
い。なぜならば、0.5重量%未満であると誘電体の誘
電率が大きくならず、電波吸収体の薄型化が図り難くな
り、また、10重量%を越えると導電性となるために電
波が反射される場合があり、電波吸収体としての機能が
低下する恐れがあるからである。The carbon fiber used in the radio wave absorber of the present invention is not particularly limited, but has a diameter of 1 to 50 μm,
A length of 0.1 to 2 mm is desirable. This is because if the aspect ratio is too small, the dielectric constant of the dielectric does not increase, making it difficult to reduce the thickness of the electromagnetic wave absorber, and if the fiber becomes too long, it becomes difficult to disperse it in the phenol resin foam. Because. The content of carbon fibers in the dielectric material of the radio wave absorber is not particularly limited, but is preferably 0.5 to 10% by weight. This is because if it is less than 0.5% by weight, the dielectric constant of the dielectric does not increase, making it difficult to reduce the thickness of the radio wave absorber, and if it exceeds 10% by weight, it becomes conductive and radio waves are reflected. In some cases, the function as a radio wave absorber may be deteriorated.
【0012】本発明における誘電体の一方の面に貼着さ
れる導電体については、導電性を有し電波を反射するも
のであればよく、例えば銅板や鉄板等の各種金属板が使
用でき、また、貼着方法についても特に限定はなく、接
着剤等を用いて貼着すればよい。The conductor attached to one surface of the dielectric in the present invention may be any one having conductivity and reflecting radio waves, and various metal plates such as copper plate and iron plate can be used, There is no particular limitation on the sticking method, and the sticking may be performed using an adhesive or the like.
【0013】[0013]
【実施例】以下、本発明を実施例及び比較例に基づいて
説明する。The present invention will be described below based on examples and comparative examples.
【0014】(実施例1)フェノール樹脂発泡材(東洋
ゴム工業社製、品番A−491)と直径13μm、長さ
0.7mmの炭素繊維とを、フェノール樹脂発泡材と炭
素繊維の合計量に対する炭素繊維の含有割合が3重量%
となるように、配合、混合した後、加熱してフリーフォ
ームで発泡させた。得られた炭素繊維を含有するフェノ
ール樹脂発泡体を厚さ4cmの板状の誘電体とし、次い
で、この誘電体の一方の面に厚さが0.2mmの銅板を
接着剤を用いて貼り合わせて電波吸収体を作製した。得
られた電波吸収体の反射係数の測定結果を図2に示す。(Example 1) Phenolic resin foam material (manufactured by Toyo Tire & Rubber Co., Ltd., product number A-491) and carbon fiber having a diameter of 13 μm and a length of 0.7 mm were added to the total amount of the phenol resin foam material and the carbon fiber. Carbon fiber content is 3% by weight
The mixture was mixed and mixed so as to be The obtained phenol resin foam containing carbon fiber was used as a plate-shaped dielectric having a thickness of 4 cm, and then a copper plate having a thickness of 0.2 mm was attached to one surface of this dielectric using an adhesive. To produce a radio wave absorber. The measurement result of the reflection coefficient of the obtained electromagnetic wave absorber is shown in FIG.
【0015】(実施例2)フェノール樹脂発泡材(東洋
ゴム工業社製、品番A−491)と直径13μm、長さ
0.7mmの炭素繊維とを、フェノール樹脂発泡材と炭
素繊維の合計量に対する炭素繊維の含有割合が3重量%
となるように、配合、混合した後、加熱してフリーフォ
ームで発泡させた。得られた炭素繊維を含有するフェノ
ール樹脂発泡体を厚さ2cmの板状の誘電体とし、次い
で、この誘電体の一方の面に厚さが0.2mmの銅板を
接着剤を用いて貼り合わせて電波吸収体を作製した。得
られた電波吸収体の反射係数の測定結果を図3に示す。(Example 2) Phenolic resin foam material (manufactured by Toyo Tire & Rubber Co., Ltd., product number A-491) and carbon fiber having a diameter of 13 μm and a length of 0.7 mm were used with respect to the total amount of the phenol resin foam material and the carbon fiber. Carbon fiber content is 3% by weight
The mixture was mixed and mixed so as to be The obtained phenol resin foam containing carbon fiber was used as a plate-shaped dielectric having a thickness of 2 cm, and then a copper plate having a thickness of 0.2 mm was attached to one surface of this dielectric using an adhesive. To produce a radio wave absorber. The measurement result of the reflection coefficient of the obtained electromagnetic wave absorber is shown in FIG.
【0016】(比較例)フェノール樹脂発泡材(東洋ゴ
ム工業社製、品番A−491)と炭素粉末とを、フェノ
ール樹脂発泡材と炭素粉末の合計量に対する炭素粉末の
含有割合が3重量%となるように、配合、混合した後、
加熱してフリーフォームで発泡させた。得られた炭素粉
末を含有するフェノール樹脂発泡体を厚さ6cmの板状
の誘電体とし、次いで、この誘電体の一方の面に厚さが
0.2mmの銅板を接着剤を用いて貼り合わせて電波吸
収体を作製した。得られた電波吸収体の反射係数の測定
結果を図4に示す。(Comparative Example) Phenolic resin foam material (manufactured by Toyo Tire & Rubber Co., Ltd., product number A-491) and carbon powder were used, and the carbon powder content was 3% by weight based on the total amount of the phenol resin foam material and carbon powder. So that after mixing and mixing,
It was heated and foamed in free foam. The obtained phenol resin foam containing carbon powder is used as a plate-shaped dielectric having a thickness of 6 cm, and then a copper plate having a thickness of 0.2 mm is attached to one surface of the dielectric with an adhesive. To produce a radio wave absorber. The measurement result of the reflection coefficient of the obtained electromagnetic wave absorber is shown in FIG.
【0017】図2〜図4の結果から明らかなように、炭
素繊維を含有するフェノール樹脂発泡体を誘電体とした
実施例1及び実施例2は、炭素粉末を含有するフェノー
ル樹脂発泡体を誘電体とした比較例に比べ、誘電体の厚
さが薄くて、100〜900MHz程度の周波数の電波
を吸収することが可能な電波吸収体となっている。As is clear from the results of FIGS. 2 to 4, in Examples 1 and 2 in which the phenol resin foam containing carbon fibers was used as the dielectric, the phenol resin foam containing carbon powder was used as the dielectric. The thickness of the dielectric is smaller than that of the comparative example, which is a body, and it is a radio wave absorber capable of absorbing radio waves having a frequency of about 100 to 900 MHz.
【0018】[0018]
【発明の効果】請求項1〜請求項3に係る発明の電波吸
収体は、フェノール樹脂発泡体中に炭素繊維が分散され
ている誘電体と該誘電体の一方の面に貼着される導電体
とからなっているので、薄い厚さで、100〜900M
Hz程度の周波数の電波を吸収することが可能であり、
さらに軽量でかつ準不燃性であるという好適な性能を備
える電波吸収体である。The radio wave absorber of the invention according to claims 1 to 3 is a dielectric material in which carbon fibers are dispersed in a phenol resin foam, and a conductive material attached to one surface of the dielectric material. As it consists of a body, it has a thin thickness of 100-900M.
It is possible to absorb radio waves with a frequency of about Hz,
Further, it is a radio wave absorber having suitable performances that are lighter weight and quasi-incombustible.
【図1】本発明の電波吸収体の構成を示す概略断面図で
ある。FIG. 1 is a schematic cross-sectional view showing a configuration of a radio wave absorber of the present invention.
【図2】実施例1で得られた電波吸収体の反射係数の測
定結果示すグラフである。FIG. 2 is a graph showing the measurement results of the reflection coefficient of the radio wave absorber obtained in Example 1.
【図3】実施例2で得られた電波吸収体の反射係数の測
定結果示すグラフである。FIG. 3 is a graph showing the measurement results of the reflection coefficient of the radio wave absorber obtained in Example 2.
【図4】比較例で得られた電波吸収体の反射係数の測定
結果示すグラフである。FIG. 4 is a graph showing a measurement result of a reflection coefficient of a radio wave absorber obtained in a comparative example.
1 フェノール樹脂発泡体 2 炭素繊維 3 誘電体 4 導電体 1 Phenolic resin foam 2 Carbon fiber 3 Dielectric 4 Conductor
Claims (3)
散されている誘電体と該誘電体の一方の面に貼着される
導電体とからなることを特徴とする電波吸収体。1. A radio wave absorber comprising a dielectric material in which carbon fibers are dispersed in a phenol resin foam and a conductor attached to one surface of the dielectric material.
5〜10重量%であることを特徴とする請求項1記載の
電波吸収体。2. The content of carbon fiber in the dielectric is 0.
The radio wave absorber according to claim 1, which is 5 to 10% by weight.
する請求項1又は請求項2記載の電波吸収体。3. The radio wave absorber according to claim 1, wherein the conductor is a metal plate.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP7246089A JPH0992996A (en) | 1995-09-25 | 1995-09-25 | Wave absorber |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP7246089A JPH0992996A (en) | 1995-09-25 | 1995-09-25 | Wave absorber |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH0992996A true JPH0992996A (en) | 1997-04-04 |
Family
ID=17143333
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP7246089A Withdrawn JPH0992996A (en) | 1995-09-25 | 1995-09-25 | Wave absorber |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0992996A (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1999005752A2 (en) * | 1997-07-23 | 1999-02-04 | Cuming Microwave Corporation | Radar absorber and method of manufacture |
JP2000299588A (en) * | 1999-04-15 | 2000-10-24 | Takenaka Komuten Co Ltd | Electromagnetic wave shielding panel |
EP1930364A1 (en) * | 2006-12-04 | 2008-06-11 | Université Catholique de Louvain | Polymer composite material structures comprising carbon based conductive loads |
WO2008068042A3 (en) * | 2006-12-04 | 2008-08-07 | Univ Catholique Louvain | Polymer composite material structures comprising carbon based conductive loads |
EP1876018A4 (en) * | 2005-04-12 | 2010-06-16 | Ubiquitous Environment Company | All-weather radio wave reflector/absorber and its assembling structure |
-
1995
- 1995-09-25 JP JP7246089A patent/JPH0992996A/en not_active Withdrawn
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1999005752A2 (en) * | 1997-07-23 | 1999-02-04 | Cuming Microwave Corporation | Radar absorber and method of manufacture |
WO1999005752A3 (en) * | 1997-07-23 | 1999-06-17 | Cuming Microwave Corp | Radar absorber and method of manufacture |
US6043769A (en) * | 1997-07-23 | 2000-03-28 | Cuming Microware Corporation | Radar absorber and method of manufacture |
JP2000299588A (en) * | 1999-04-15 | 2000-10-24 | Takenaka Komuten Co Ltd | Electromagnetic wave shielding panel |
EP1876018A4 (en) * | 2005-04-12 | 2010-06-16 | Ubiquitous Environment Company | All-weather radio wave reflector/absorber and its assembling structure |
EP1930364A1 (en) * | 2006-12-04 | 2008-06-11 | Université Catholique de Louvain | Polymer composite material structures comprising carbon based conductive loads |
WO2008068042A3 (en) * | 2006-12-04 | 2008-08-07 | Univ Catholique Louvain | Polymer composite material structures comprising carbon based conductive loads |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
A300 | Withdrawal of application because of no request for examination |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 20021203 |