JPH07193388A - Micro wave and millimeter wave absorber - Google Patents
Micro wave and millimeter wave absorberInfo
- Publication number
- JPH07193388A JPH07193388A JP34728293A JP34728293A JPH07193388A JP H07193388 A JPH07193388 A JP H07193388A JP 34728293 A JP34728293 A JP 34728293A JP 34728293 A JP34728293 A JP 34728293A JP H07193388 A JPH07193388 A JP H07193388A
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- unit
- absorber
- electromagnetic wave
- radio wave
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は電波吸収体、特に電波暗
室用電波吸収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 radio wave absorber, and more particularly to a radio wave absorber for an anechoic chamber.
【０００２】[0002]
【従来の技術】電子機器の評価や各種アンテナの評価等
に電波暗室が利用されているが、電波暗室用の電波吸収
体としては、対応周波数の広帯域性および高い電波吸収
性能を図るため、一般に、外形がくさび形状のもの、も
しくは四角錐形状のものが広く用いられている。2. Description of the Related Art An anechoic chamber is used for evaluation of electronic devices and various antennas. However, as an electromagnetic wave absorber for an anechoic chamber, it is generally used in order to achieve a wide band of corresponding frequencies and high electromagnetic wave absorption performance. Widely used are wedge-shaped ones or quadrangular pyramid-shaped ones.
【０００３】これらの電波暗室および、電波吸収体は電
波が一般に使用されているＳＨＦ帯以下の周波数帯域で
主に使用されている。These anechoic chambers and wave absorbers are mainly used in the frequency band below the SHF band where radio waves are generally used.
【０００４】[0004]
【発明が解決しようとする課題】ところで近年レーダや
通信機材等の使用周波数がＥＨＦ帯に移行しつつあり、
それに伴い電波吸収体も従来から使用されているＳＨＦ
帯以下の周波数領域に加えて、ＥＨＦ帯においても高い
電波吸収性能が要求されだしている。By the way, in recent years, the frequencies used in radar and communication equipment are shifting to the EHF band.
Along with that, SHF, which has been used for radio wave absorbers
In addition to the frequency range below the band, high electromagnetic wave absorption performance is also required in the EHF band.
【０００５】一方、現状の電波吸収体は一般にＳＨＦ帯
以下の周波数を対象として、いかに低周波数から電波吸
収体の長さを短くして高性能化するかに設計の主眼がお
かれており、ＥＨＦ帯以上の高周波数での吸収性能まで
含めた広帯域な設計は行われていない。そのため、現状
のＳＨＦ帯以下で用いられている電波吸収体をそのまま
用いた場合、ＥＨＦ帯では吸収性能の低下が見られ、Ｓ
ＨＦ帯で約５０ｄＢの電波吸収特性を持つ電波吸収体が
ＥＨＦ帯では２６〜４３ｄＢ程度に電波吸収特性が低下
していることが報告されている。（信学論(B-II ),J72-
B-II,9, pp.494-498および信学論(B-II ),J73-B-II,2,p
p.124-126 ）一方、ＥＨＦ帯用に設計された電波吸収体
はＥＨＦ帯においては良好な吸収特性を示すが、このよ
うな電波吸収体はＳＨＦ帯以下の帯域では高性能な電波
吸収特性を有しておらず、周波数３ＧＨｚで１０から２
０ｄＢ程度の電波吸収特性となっている。On the other hand, current radio wave absorbers are generally designed for frequencies below the SHF band, and how to shorten the length of the radio wave absorber from the low frequency to improve the performance, Broadband design including absorption performance at high frequencies above the EHF band has not been performed. Therefore, when the electromagnetic wave absorber used in the current SHF band or lower is used as it is, the absorption performance is deteriorated in the EHF band.
It has been reported that a radio wave absorber having a radio wave absorption characteristic of about 50 dB in the HF band has a radio wave absorption characteristic reduced to about 26 to 43 dB in the EHF band. (Physics (B-II), J72-
B-II, 9, pp.494-498 and Theological Theory (B-II), J73-B-II, 2, p
p.124-126) On the other hand, electromagnetic wave absorbers designed for the EHF band show good absorption characteristics in the EHF band, but such electromagnetic wave absorbers have high performance in the SHF band and below. 10 to 2 at a frequency of 3 GHz
The electromagnetic wave absorption characteristic is about 0 dB.
【０００６】本発明は、ＳＨＦ帯からＥＨＦ帯に至り広
帯域な周波数範囲で高い電波吸収特性を有する電波吸収
体を提供することを目的とする。An object of the present invention is to provide a radio wave absorber having high radio wave absorption characteristics in a wide frequency range from the SHF band to the EHF band.
【０００７】[0007]
【課題を解決するための手段】上記の目的を達成するた
め、本発明の電波吸収体は、錐状部を有する単位吸収体
の集合体で構成され、周波数３ＧＨｚでの複素比誘電率In order to achieve the above object, the radio wave absorber of the present invention comprises an aggregate of unit absorbers having a conical portion, and has a complex relative dielectric constant at a frequency of 3 GHz.
【０００８】[0008]
【数３】 [Equation 3]
【０００９】の絶対値の大きさMagnitude of absolute value of
【００１０】[0010]
【数４】 [Equation 4]
【００１１】が２以上、９以下で誘電正接ｔａｎδ（＝
ε"r/ ε'r）が０．６以上の誘電損失材料で構成され、
前記単位吸収体の全長（Ｈ）が１５０ｍｍ以上であり、
錐状部の長さ（Ｌ）が１００ｍｍ以上であり、錐状部の
長さ（Ｌ）は、単位吸収体の底部の一単位の長さ（Ｗ）
の３倍以上であって、前記一単位の長さ（Ｗ）が１００
ｍｍ以下である。Is 2 or more and 9 or less, the dielectric loss tangent tan δ (=
ε "r / ε 'r) is composed of 0.6 or more dielectric loss material,
The total length (H) of the unit absorber is 150 mm or more,
The length (L) of the conical portion is 100 mm or more, and the length (L) of the conical portion is one unit length (W) of the bottom of the unit absorbent body.
3 times or more, and the length (W) of the one unit is 100
mm or less.
【００１２】また本発明における電波吸収体の基材は、
発泡ポリエチレン、発泡ポリウレタン、発泡ポリスチレ
ン等の有機樹脂の発泡材料等を使用するが、耐久性及び
加工性等の面から発泡ポリエチレンを基材として用いる
のが好ましい。The base material of the radio wave absorber according to the present invention is
An organic resin foam material such as expanded polyethylene, expanded polyurethane, expanded polystyrene or the like is used, but it is preferable to use expanded polyethylene as a base material in terms of durability and processability.
【００１３】[0013]
【作用】対象とする電磁波の下限周波数の波長λに対
し、電波のエネルギーを充分に減衰させるため電波吸収
体の長さを１．５λ以上、および電波の導入部分である
くさび形状もしくは、角錐形状、円錐形状の長さをλ以
上とすることにより入力インピーダンスの変化が滑らか
となり、効率的に電波を吸収し、低周波数領域にて吸収
性能を確保することができる。[Function] For the wavelength λ of the lower limit frequency of the target electromagnetic wave, the length of the electromagnetic wave absorber is 1.5λ or more in order to sufficiently attenuate the energy of the electromagnetic wave, and the wedge shape or the pyramid shape where the electromagnetic wave is introduced. By setting the length of the conical shape to be λ or more, the change of the input impedance becomes smooth, the radio waves are efficiently absorbed, and the absorption performance can be secured in the low frequency region.
【００１４】すなわち、対象とする電磁波の下限周波数
をＳＨＦ帯の下限周波数である３ＧＨｚとした場合、波
長は１００ｍｍなので電波吸収体の長さを１５０ｍｍ以
上、くさび形状もしくは、角錐形状、円錐形状の長さを
１００ｍｍ以上とすることによりＳＨＦ帯の下限周波数
にて高い吸収性能を得ることができる。また、周波数３
ＧＨｚでの複素比誘電率の大きさが２未満、且つ誘電正
接が０．６以下の吸収材料で電波吸収体を構成した場
合、十分な電波の減衰が得られないので、周波数３ＧＨ
ｚでの複素比誘電率の大きさが２以上、誘電正接が０．
６以上の吸収材料で電波吸収体を構成することにより良
好な電波吸収特性を得ることができる。That is, when the lower limit frequency of the target electromagnetic wave is 3 GHz, which is the lower limit frequency of the SHF band, the wavelength is 100 mm, so the length of the electromagnetic wave absorber is 150 mm or more, and the length of the wedge shape, the pyramid shape, or the conical shape. By setting the thickness to 100 mm or more, high absorption performance can be obtained at the lower limit frequency of the SHF band. Also, frequency 3
When the radio wave absorber is made of an absorbing material having a complex relative permittivity at GHz of less than 2 and a dielectric loss tangent of 0.6 or less, sufficient radio wave attenuation cannot be obtained.
The magnitude of complex relative permittivity at z is 2 or more, and the dielectric loss tangent is 0.
By constructing a radio wave absorber with six or more absorbing materials, good radio wave absorption characteristics can be obtained.
【００１５】一方、電波の周波数が高くなるに従い、波
長が短くなるため電波の直進性が高まり、くさび形状部
分もしくは、角錐、円錐形状部分間の隙間に電波が直接
入射するが、くさび形状もしくは、角錐形状、円錐形状
の長さとくさび形状もしくは、角錐形状、円錐形状の一
単位の巾の比を３以上とすることによりくさび形状部分
内、角錐形状部分内、円錐形状部分内での電波の多重反
射が増加して電波が効率よく減衰するため高周波数領域
においても良好な電波吸収特性を得ることができる。た
だし、波長に対しくさび形状、角錐形状、円錐形状部分
間の隙間が大きくなりすぎると電波が容易に隙間に入射
し、散乱波が増大するため隙間の巾は１００ｍｍ以下に
することが望ましい。また、周波数３ＧＨｚでの複素比
誘電率の大きさが９以下の吸収材料で電波吸収体を構成
することにより電波吸収体表面での電波の反射を抑え、
電波吸収体表面での電波の反射の増大による電波吸収特
性の低下を防ぐことができる。その結果、広帯域な周波
数範囲で良好な電波吸収特性を得ることができる。On the other hand, as the frequency of the radio wave becomes higher, the wavelength becomes shorter, so that the straightness of the radio wave is improved and the radio wave is directly incident on the wedge-shaped portion or the gap between the pyramid and the cone-shaped portion. By setting the ratio of the length of the pyramid shape, the cone shape to the wedge shape, or the width of one unit of the pyramid shape and the cone shape to 3 or more, the radio waves are multiplexed in the wedge shape portion, the pyramid shape portion, and the cone shape portion. Since reflection increases and radio waves are efficiently attenuated, good radio wave absorption characteristics can be obtained even in a high frequency region. However, if the gap between the wedge-shaped, pyramidal-shaped, and conical-shaped portions becomes too large with respect to the wavelength, radio waves easily enter the gap and scattered waves increase, so the width of the gap is preferably 100 mm or less. Further, by suppressing the reflection of radio waves on the surface of the radio wave absorber by configuring the radio wave absorber with an absorbing material having a complex relative permittivity of 9 or less at a frequency of 3 GHz,
It is possible to prevent the deterioration of the radio wave absorption characteristics due to the increase of the reflection of radio waves on the surface of the radio wave absorber. As a result, good radio wave absorption characteristics can be obtained in a wide frequency range.
【００１６】さらに波長が短くなることにより、波長に
対するくさび形状、角錐形状、円錐形状部分の先端部の
面積の割合が増し、先端部からの電波の反射が吸収特性
の低下をもたらす、そこでくさび形状、角錐形状、円錐
形状部分の先端部の面積を底部の面積の１００分の１以
下に抑えることにより良好な吸収特性を得ることができ
る。As the wavelength is further shortened, the ratio of the area of the tip of the wedge shape, the pyramid shape, or the conical shape to the wavelength is increased, and the reflection of the radio wave from the tip causes the deterioration of the absorption characteristic. Good absorption characteristics can be obtained by suppressing the area of the tip of the pyramid-shaped or conical-shaped portion to 1/100 or less of the area of the bottom.
【００１７】[0017]
【実施例】本発明では、電波暗室の壁、天井、又は床を
錐状又はくさび状の誘電体材質から成る単位吸収体の集
合体で覆う。DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, the wall, ceiling, or floor of an anechoic chamber is covered with an aggregate of unit absorbers made of a cone-shaped or wedge-shaped dielectric material.
【００１８】単位吸収体は台部Ｄと錐状部Ｅを有し、そ
の構造例を図１０に示す。（ａ）は角錐形状で、台部の
一辺の長さはＷ、電波吸収体の全長がＨ、錐状部の長さ
がＬである。（ｂ）はくさび形状で、台部は長辺の長さ
がＬＷ、短辺の長さがＷの直方体、全長Ｈ、錐状部の長
さがＬである。（ｃ）は円錐状で、台部は直径Ｗの円
柱、全長Ｈ、錐状部の長さがＬである。ここで、単位吸
収体の底部の一単位の長さ（Ｗ）として、角錐及びくさ
びの場合は台部Ｄの辺のうち短い方の辺の長さ、円錐の
場合は台部Ｄの直径を取る。The unit absorber has a pedestal portion D and a conical portion E, and its structural example is shown in FIG. (A) is a pyramid shape, the length of one side of the base is W, the total length of the radio wave absorber is H, and the length of the pyramidal part is L. (B) has a wedge shape, and the base has a rectangular parallelepiped having a long side length of LW, a short side length of W, a total length H, and a conical portion length L. (C) has a conical shape, and the base has a cylinder with a diameter W, the total length H, and the length of the conical portion L. Here, as one unit length (W) of the bottom of the unit absorber, the length of the shorter one of the sides of the base D in the case of a pyramid and a wedge, and the diameter of the base D in the case of a cone. take.
【００１９】錐状体の先端は理論的にはとがっているこ
とが好ましいが、実際にはある面積を持つ。本発明では
図１０（ｄ）に示すように、単位吸収体の底部の面積Ｓ
0 と先端の面積Ｓ1 の比Ｓ0 ／Ｓ1 により先端部の構造
を規定する。Although it is theoretically preferable that the tip of the pyramid is sharp, it actually has a certain area. In the present invention, as shown in FIG. 10D, the area S of the bottom of the unit absorber is
The 0 and tip ratio S 0 / S 1 of the area S 1 of defining the structure of the tip.
【００２０】本発明で用いる単位吸収体は、誘電体で、
周波数３ＧＨｚでの複素比誘電率の絶対値は２以上で９
以下であり、複素比誘電率の虚部の実部に対する比であ
る誘電正接ｔａｎδの値は０．６以上である。The unit absorber used in the present invention is a dielectric,
The absolute value of complex relative permittivity at a frequency of 3 GHz is 2 or more and 9
The value of the dielectric loss tangent tan δ, which is the ratio of the complex relative permittivity to the real part of the imaginary part, is 0.6 or more.
【００２１】図１１は、３ＧＨｚで測定した複素比誘電
率の絶対値（横軸）と反射減衰量（縦軸）の関係を示
し、上記絶対値がほぼ２以上の時、反射減衰量が３０ｄ
Ｂ以上となることがわかる。なお図１１でｔａｎδ＝
０．６である。FIG. 11 shows the relationship between the absolute value (horizontal axis) of the complex relative permittivity measured at 3 GHz and the return loss (vertical axis). When the absolute value is approximately 2 or more, the return loss is 30 d.
It turns out that it becomes B or more. In FIG. 11, tan δ =
It is 0.6.
【００２２】複素比誘電率の絶対値の上限値は単位吸収
体の製造条件で規定される。吸収体は例えば発泡ポリエ
チレン等の有機樹脂を用い、例えばカーボンを混合して
誘電率を調節する。カーボンの混合率を上げて誘電率を
大きくすると成形が困難になるので、実用的には９以下
で使用する。The upper limit of the absolute value of the complex relative dielectric constant is specified by the manufacturing conditions of the unit absorber. An organic resin such as expanded polyethylene is used as the absorber, and carbon is mixed to adjust the dielectric constant. If the mixing ratio of carbon is increased to increase the dielectric constant, molding becomes difficult. Therefore, practically, use 9 or less.
【００２３】図１２は誘電正接ｔａｎδと反射減衰量の
測定結果を示し、ｔａｎδの値がほぼ０．６以上のと
き、反射減衰量が３０ｄＢ以上になることがわかる。FIG. 12 shows the measurement results of the dielectric loss tangent tan δ and the return loss, and it can be seen that the return loss becomes 30 dB or more when the value of tan δ is about 0.6 or more.
【００２４】次に、単位吸収体の寸法の関係について述
べる。Next, the dimensional relationship of the unit absorber will be described.
【００２５】（実施例１）周波数３ＧＨｚでの複素比誘
電率(Example 1) Complex relative permittivity at a frequency of 3 GHz
【００２６】[0026]
【数５】 [Equation 5]
【００２７】が[0027]
【００２８】[0028]
【数６】 [Equation 6]
【００２９】の電波吸収材料を用い、電波吸収体の長さ
１５０ｍｍ、四角錐形状部分の長さ１００ｍｍ、四角錐
の一単位の幅３０ｍｍで電波吸収体を製作し、周波数２
〜１０ＧＨｚで電波吸収特性を測定した。電波吸収特性
測定結果を図１に示す。３ＧＨｚでの電波吸収特性が４
０ｄＢ以上であり良好な吸収特性を得ている。Using the electromagnetic wave absorbing material (1), an electromagnetic wave absorber having a length of 150 mm, a quadrangular pyramid-shaped portion having a length of 100 mm, and a quadrangular pyramid having a width of 30 mm is manufactured.
The electromagnetic wave absorption characteristics were measured at 10 GHz. The measurement result of the radio wave absorption characteristics is shown in FIG. The electromagnetic wave absorption characteristic at 3 GHz is 4
It is 0 dB or more, and good absorption characteristics are obtained.
【００３０】（実施例２）周波数３ＧＨｚでの複素比誘
電率(Example 2) Complex relative permittivity at a frequency of 3 GHz
【００３１】[0031]
【数７】 [Equation 7]
【００３２】が[0032]
【００３３】[0033]
【数８】 [Equation 8]
【００３４】の電波吸収材料を用い、電波吸収体の長さ
１５０ｍｍ、四角錐形状部分の長さ１００ｍｍ、四角錐
の一単位の幅３０ｍｍ、５０ｍｍ、１００ｍｍで電波吸
収体を製作し、周波数１００ＧＨｚで電波吸収特性を測
定した。四角錐の一単位の幅と電波吸収特性の関係を図
２に示す。四角錐の一単位の幅と四角錐の長さの比が３
以上となっている四角錐の幅３０ｍｍのときにおいて電
波吸収特性が５０ｄＢ以上となっており、良好な吸収特
性を示している。Using the electromagnetic wave absorbing material (1), an electromagnetic wave absorber having a length of 150 mm, a quadrangular pyramid shaped portion of 100 mm, and a unit width of quadrangular pyramid of 30 mm, 50 mm, and 100 mm is manufactured, and the frequency is 100 GHz. Radio wave absorption characteristics were measured. FIG. 2 shows the relationship between the width of one unit of the quadrangular pyramid and the electromagnetic wave absorption characteristics. The ratio of the width of one unit of the pyramid to the length of the pyramid is 3
When the width of the quadrangular pyramid is 30 mm as described above, the radio wave absorption characteristic is 50 dB or more, which shows a good absorption characteristic.
【００３５】（実施例３）周波数３ＧＨｚでの複素比誘
電率(Example 3) Complex relative permittivity at a frequency of 3 GHz
【００３６】[0036]
【数９】 [Equation 9]
【００３７】が[0037]
【００３８】[0038]
【数１０】 [Equation 10]
【００３９】の電波吸収材料を用い、電波吸収体の長さ
１５０ｍｍ、くさび形状部分の長さ１００ｍｍ、くさび
の一単位の幅３０ｍｍ、５０ｍｍ、１００ｍｍで電波吸
収体を製作し、周波数１００ＧＨｚで電波吸収特性を測
定した。くさびの一単位の幅と電波吸収特性の関係を図
３に示す。くさびの一単位の幅とくさびの長さの比が３
以上となっているくさびの幅３０ｍｍのときにおいて電
波吸収特性が５０ｄＢ以上となっており、良好な吸収特
性を示している。Using the electromagnetic wave absorbing material (1), an electromagnetic wave absorber having a length of 150 mm, a wedge-shaped portion of 100 mm, a wedge unit width of 30 mm, 50 mm, and 100 mm is manufactured, and the electromagnetic wave is absorbed at a frequency of 100 GHz. The properties were measured. The relationship between the width of one unit of the wedge and the electromagnetic wave absorption characteristics is shown in FIG. The ratio of the width of one unit of wedge to the length of wedge is 3
When the width of the wedge is 30 mm as described above, the radio wave absorption characteristic is 50 dB or more, which shows a good absorption characteristic.
【００４０】（実施例４）周波数３ＧＨｚでの複素比誘
電率(Example 4) Complex relative permittivity at a frequency of 3 GHz
【００４１】[0041]
【数１１】 [Equation 11]
【００４２】がIs
【００４３】[0043]
【数１２】 [Equation 12]
【００４４】の電波吸収材料を用い、電波吸収体の長さ
５００ｍｍ、四角錐形状部分の長さ４５０ｍｍ、四角錐
の一単位の幅１００ｍｍ、１５０ｍｍ、２００ｍｍ、３
００ｍｍで電波吸収体を製作し、周波数１００ＧＨｚで
電波吸収特性を測定した。四角錐の一単位の幅と電波吸
収特性の関係を図４に示す。四角錐の一単位の幅が１０
０ｍｍのときにおいて電波吸収特性が５０ｄＢ以上とな
っており、良好な吸収特性を示している。Using the radio wave absorbing material of, the length of the radio wave absorber is 500 mm, the length of the quadrangular pyramid portion is 450 mm, the width of one unit of the quadrangular pyramid is 100 mm, 150 mm, 200 mm, 3
A radio wave absorber was manufactured with a length of 00 mm, and the radio wave absorption characteristics were measured at a frequency of 100 GHz. FIG. 4 shows the relationship between the width of one unit of the quadrangular pyramid and the electromagnetic wave absorption characteristics. The width of one unit of square pyramid is 10
When it is 0 mm, the electromagnetic wave absorption characteristic is 50 dB or more, indicating a good absorption characteristic.
【００４５】（実施例５）周波数３ＧＨｚでの複素比誘
電率(Embodiment 5) Complex relative permittivity at a frequency of 3 GHz
【００４６】[0046]
【数１３】 [Equation 13]
【００４７】がIs
【００４８】[0048]
【数１４】 [Equation 14]
【００４９】の電波吸収材料を用い、電波吸収体の長さ
３００ｍｍ、四角錐形状部分の長さ２５０ｍｍ、四角錐
の底部の一単位の幅１００ｍｍ、四角錐の先端部の一単
位の幅１ｍｍ、５ｍｍ、１０ｍｍ、２０ｍｍで電波吸収
体を製作し、周波数１００ＧＨｚで電波吸収特性を測定
した。四角錐の先端部と底部の面積比と電波吸収特性の
関係を図９に示す。四角錐の先端部と底部の面積比が
０．０１のときにおいて電波吸収特性が５０ｄＢ以上と
なっており、良好な吸収特性を示している。Using the electromagnetic wave absorbing material of, the length of the electromagnetic wave absorber is 300 mm, the length of the quadrangular pyramid is 250 mm, the width of one unit of the bottom of the quadrangular pyramid is 100 mm, and the width of one unit of the tip of the quadrangular pyramid is 1 mm, Radio wave absorbers were manufactured with 5 mm, 10 mm, and 20 mm, and the radio wave absorption characteristics were measured at a frequency of 100 GHz. FIG. 9 shows the relationship between the area ratio between the tip and the bottom of the quadrangular pyramid and the electromagnetic wave absorption characteristics. When the area ratio of the tip part to the bottom part of the quadrangular pyramid is 0.01, the radio wave absorption characteristic is 50 dB or more, which shows a good absorption characteristic.
【００５０】（比較例１）周波数３ＧＨｚでの複素比誘
電率(Comparative Example 1) Complex relative permittivity at a frequency of 3 GHz
【００５１】[0051]
【数１５】 [Equation 15]
【００５２】がIs
【００５３】[0053]
【数１６】 [Equation 16]
【００５４】の電波吸収材料を用い、電波吸収体の長さ
１００ｍｍ、四角錐形状部分の長さ１００ｍｍ、四角錐
の一単位の幅３０ｍｍで電波吸収体を製作し、周波数２
〜１０ＧＨｚで電波吸収特性を測定した。電波吸収特性
測定結果を図５に示す。３ＧＨｚでの電波吸収特性が１
０ｄＢ程度であり、実施例１と比較して電波吸収特性が
大きく低下している。Using the electromagnetic wave absorbing material of, the electromagnetic wave absorber having a length of 100 mm, a quadrangular pyramid shaped portion of 100 mm in length, and a width of 30 mm of one unit of the quadrangular pyramid is manufactured, and a frequency of 2
The electromagnetic wave absorption characteristics were measured at 10 GHz. The measurement result of the radio wave absorption characteristics is shown in FIG. Electromagnetic wave absorption characteristic at 3 GHz is 1
It is about 0 dB, and the radio wave absorption characteristics are greatly reduced as compared with the first embodiment.
【００５５】（比較例２）周波数３ＧＨｚでの複素比誘
電率(Comparative Example 2) Complex relative permittivity at a frequency of 3 GHz
【００５６】[0056]
【数１７】 [Equation 17]
【００５７】がIs
【００５８】[0058]
【数１８】 [Equation 18]
【００５９】の電波吸収材料を用い、電波吸収体の長さ
１５０ｍｍ、四角錐形状部分の長さ５０ｍｍ、四角錐の
一単位の幅３０ｍｍで電波吸収体を製作し、周波数２〜
１０ＧＨｚで電波吸収特性を測定した。電波吸収特性測
定結果を図６に示す。３ＧＨｚでの電波吸収特性が３０
ｄＢ程度であり、実施例１と比較して電波吸収特性が低
下している。Using the electromagnetic wave absorbing material of, the electromagnetic wave absorber is manufactured with a length of the electromagnetic wave absorber of 150 mm, a length of the quadrangular pyramid portion of 50 mm, and a width of 30 mm of one unit of the quadrangular pyramid.
The electromagnetic wave absorption characteristics were measured at 10 GHz. The measurement result of the radio wave absorption characteristics is shown in FIG. The electromagnetic wave absorption characteristic at 3 GHz is 30
It is about dB, and the radio wave absorption characteristic is lower than that of the first embodiment.
【００６０】（比較例３）周波数３ＧＨｚでの複素比誘
電率(Comparative Example 3) Complex relative permittivity at a frequency of 3 GHz
【００６１】[0061]
【数１９】 [Formula 19]
【００６２】がIs
【００６３】[0063]
【数２０】 [Equation 20]
【００６４】の電波吸収材料を用い、電波吸収体の長さ
１５０ｍｍ、四角錐形状部分の長さ１００ｍｍ、四角錐
の一単位の幅３０ｍｍで電波吸収体を製作し、周波数２
〜１０ＧＨｚで電波吸収特性を測定した。電波吸収特性
測定結果を図７に示す。３ＧＨｚでの電波吸収特性が２
０ｄＢ程度であり、実施例１と比較して電波吸収特性が
低下している。Using the electromagnetic wave absorbing material (1), an electromagnetic wave absorber having a length of 150 mm, a quadrangular pyramid-shaped portion having a length of 100 mm, and a quadrangular pyramid having a width of 30 mm was manufactured.
The electromagnetic wave absorption characteristics were measured at 10 GHz. The measurement result of the radio wave absorption characteristics is shown in FIG. The electromagnetic wave absorption characteristic at 3 GHz is 2
It is about 0 dB, and the electromagnetic wave absorption characteristic is lower than that of the first embodiment.
【００６５】（比較例４）周波数３ＧＨｚでの複素比誘
電率(Comparative Example 4) Complex relative permittivity at a frequency of 3 GHz
【００６６】[0066]
【数２１】 [Equation 21]
【００６７】がIs
【００６８】[0068]
【数２２】 [Equation 22]
【００６９】の電波吸収材料を用い、電波吸収体の長さ
１５０ｍｍ、四角錐形状部分の長さ１００ｍｍ、四角錐
の一単位の幅３０ｍｍ、５０ｍｍ、１００ｍｍで電波吸
収体を製作し、周波数１００ＧＨｚで電波吸収特性を測
定した。四角錐の一単位の幅と電波吸収特性の関係を図
８に示す。四角錐の一単位の幅と四角錐の長さの比が３
以上となっている四角錐の幅３０ｍｍのときにおいて電
波吸収特性が５０ｄＢ以下となっており、実施例２と比
較して電波吸収特性が低下している。Using the electromagnetic wave absorbing material of, the electromagnetic wave absorber was manufactured with a length of the electromagnetic wave absorber of 150 mm, a length of the quadrangular pyramid portion of 100 mm, and a width of one unit of the quadrangular pyramid of 30 mm, 50 mm, and 100 mm, and a frequency of 100 GHz. Radio wave absorption characteristics were measured. FIG. 8 shows the relationship between the width of one unit of the quadrangular pyramid and the radio wave absorption characteristics. The ratio of the width of one unit of the pyramid to the length of the pyramid is 3
When the width of the quadrangular pyramid is 30 mm, the radio wave absorption characteristic is 50 dB or less, which is lower than that of the second embodiment.
【００７０】[0070]
【発明の効果】以上のように本発明の電波吸収体はＳＨ
Ｆ帯からＥＨＦ帯に渡り良好な電波吸収特性が得られる
ため、本発明の電波吸収体を電波暗室に用いることによ
り、１つの電波暗室でＳＨＦ帯からＥＨＦ帯の対応が可
能となる。As described above, the electromagnetic wave absorber of the present invention is SH
Since a good electromagnetic wave absorption characteristic can be obtained from the F band to the EHF band, by using the electromagnetic wave absorber of the present invention in the anechoic chamber, it is possible to cope with the SHF band to the EHF band in one anechoic chamber.
【図１】本発明の実施例１の２〜１０ＧＨｚでの電波吸
収特性を示す図である。FIG. 1 is a diagram showing a radio wave absorption characteristic at 2 to 10 GHz according to a first embodiment of the present invention.
【図２】本発明の実施例２の１００ＧＨｚでの電波吸収
特性を示す図である。FIG. 2 is a diagram showing a radio wave absorption characteristic at 100 GHz according to a second embodiment of the present invention.
【図３】本発明の実施例３の１００ＧＨｚでの電波吸収
特性を示す図である。FIG. 3 is a diagram showing a radio wave absorption characteristic at 100 GHz according to a third embodiment of the present invention.
【図４】本発明の実施例４の１００ＧＨｚでの電波吸収
特性を示す図である。FIG. 4 is a diagram showing a radio wave absorption characteristic at 100 GHz according to a fourth embodiment of the present invention.
【図５】本発明の比較例１の２〜１０ＧＨｚでの電波吸
収特性を示す図である。FIG. 5 is a diagram showing radio wave absorption characteristics at 2 to 10 GHz of Comparative Example 1 of the present invention.
【図６】本発明の比較例２の２〜１０ＧＨｚでの電波吸
収特性を示す図である。FIG. 6 is a diagram showing radio wave absorption characteristics at 2 to 10 GHz of Comparative Example 2 of the present invention.
【図７】本発明の比較例３の２〜１０ＧＨｚでの電波吸
収特性を示す図である。FIG. 7 is a diagram showing radio wave absorption characteristics at 2 to 10 GHz of Comparative Example 3 of the present invention.
【図８】本発明の比較例４の１００ＧＨｚでの電波吸収
特性を示す図である。FIG. 8 is a diagram showing radio wave absorption characteristics at 100 GHz of Comparative Example 4 of the present invention.
【図９】本発明の実施例５の１００ＧＨｚでの電波吸収
特性を示す図である。FIG. 9 is a diagram showing a radio wave absorption characteristic at 100 GHz according to a fifth embodiment of the present invention.
【図１０】単位吸収体の構造例を示す。FIG. 10 shows a structural example of a unit absorber.
【図１１】複素比誘電率の絶対値と反射減衰量の関係を
示す。FIG. 11 shows the relationship between the absolute value of the complex relative permittivity and the return loss.
【図１２】誘電正接と反射減衰量の関係を示す。FIG. 12 shows the relationship between dielectric loss tangent and return loss.
Ｄ 台部 Ｅ 錐部 D stand E cone
Claims (2)
構成され、周波数３ＧＨｚでの複素比誘電率 【数１】 の絶対値の大きさ 【数２】 が２以上、９以下で誘電正接ｔａｎδ（＝ε"r/ ε'r）
が０．６以上の誘電損失材料で構成され、 前記単位吸収体の全長（Ｈ）が１５０ｍｍ以上であり、
錐状部の長さ（Ｌ）が１００ｍｍ以上であり、錐状部の
長さ（Ｌ）は、単位吸収体の底部の一単位の長さ（Ｗ）
の３倍以上であって、前記一単位の長さ（Ｗ）が１００
ｍｍ以下であることを特徴とする電波吸収体。1. A complex relative dielectric constant at a frequency of 3 GHz, which is composed of an aggregate of unit absorbers having a conical portion. The magnitude of the absolute value of But 2 or more, 9 or less with a dielectric loss tangent tanδ (= ε "r / ε 'r)
Is made of a dielectric loss material of 0.6 or more, and the total length (H) of the unit absorber is 150 mm or more,
The length (L) of the conical portion is 100 mm or more, and the length (L) of the conical portion is one unit length (W) of the bottom of the unit absorbent body.
3 times or more, and the length (W) of the one unit is 100
A radio wave absorber characterized by being less than or equal to mm.
び円錐形状から選択されるひとつであり、その先端部の
面積がくさび形状、角錐形状、または円錐形状の底面部
の面積に対し１００分の１以下であることを特徴とする
請求項１に記載の電波吸収体。2. The pyramidal portion is one selected from a wedge shape, a pyramid shape, and a conical shape, and an area of a tip portion thereof is 100 with respect to an area of a wedge shape, a pyramid shape, or a conical bottom surface portion. The electromagnetic wave absorber according to claim 1, wherein the electromagnetic wave absorber is one-third or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP34728293A JPH07193388A (en) | 1993-12-27 | 1993-12-27 | Micro wave and millimeter wave absorber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP34728293A JPH07193388A (en) | 1993-12-27 | 1993-12-27 | Micro wave and millimeter wave absorber |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07193388A true JPH07193388A (en) | 1995-07-28 |
Family
ID=18389162
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP34728293A Pending JPH07193388A (en) | 1993-12-27 | 1993-12-27 | Micro wave and millimeter wave absorber |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07193388A (en) |
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| JP2009177105A (en) * | 2008-01-25 | 2009-08-06 | Matsuoka Roofing Inc | Electromagnetic wave absorber |
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| US7471233B2 (en) | 2004-05-31 | 2008-12-30 | Tdk Corporation | Electromagnetic wave absorber |
| US7688246B2 (en) | 2005-05-10 | 2010-03-30 | Fuji Xerox Co., Ltd. | Radio wave absorber, electromagnetic field measurement system and radiated immunity system |
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| JP4602429B2 (en) * | 2008-01-25 | 2010-12-22 | 松岡瓦産業株式会社 | Radio wave absorber |
| US9276326B2 (en) | 2012-07-10 | 2016-03-01 | Kabushiki Kaisha Riken | Electromagnetic wave absorber |
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| US20140132439A1 (en) * | 2012-07-10 | 2014-05-15 | Kabushiki Kaisha Riken | Electromagnetic wave absorber |
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