JP2827286B2 - Anechoic chamber - Google Patents
Anechoic chamberInfo
- Publication number
- JP2827286B2 JP2827286B2 JP1158433A JP15843389A JP2827286B2 JP 2827286 B2 JP2827286 B2 JP 2827286B2 JP 1158433 A JP1158433 A JP 1158433A JP 15843389 A JP15843389 A JP 15843389A JP 2827286 B2 JP2827286 B2 JP 2827286B2
- Authority
- JP
- Japan
- Prior art keywords
- anechoic chamber
- parallel
- tiles
- tile
- ferrite
- 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.)
- Expired - Lifetime
Links
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- Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は電波暗室に関し、特に10m法以上の試験が可
能な大型構造に適した電波暗室に関する。Description: TECHNICAL FIELD The present invention relates to an anechoic chamber, and more particularly to an anechoic chamber suitable for a large structure capable of performing a test of 10 m or more.
（従来の技術） 電子機器の放射雑音を正確に測定するために電波暗室
内の試験場が実用化されている。従来は3m法の試験を実
施する施設が主流であったが測定精度向上、機器の大型
化などに伴い10m法の試験場も設置されるようになって
きた。このような大型電波暗室では室内空間が常に試験
周波数の波長以上であるため、全壁面からの反射波が伝
搬性能に影響する。従って、小型電波暗室に比較して反
射による伝搬異常が発生しやすい。(Prior Art) A test place in an anechoic chamber has been put to practical use in order to accurately measure radiation noise of electronic equipment. Conventionally, facilities that carry out tests using the 3m method were the mainstream, but with the improvement of measurement accuracy and the increase in size of equipment, test facilities for the 10m method have come to be set up. In such a large anechoic chamber, since the indoor space is always equal to or greater than the wavelength of the test frequency, reflected waves from all wall surfaces affect the propagation performance. Therefore, propagation abnormality due to reflection is more likely to occur than in a small anechoic chamber.
放射雑音評価用試験場の適合性は理論サイト・アッテ
ネーションからの偏差で判定され、許容偏差値は30MHz
〜1GHzの範囲で理論値±4dB以内である。このような電
波暗室に使用する電波吸収体は全周波数範囲で一定値以
上の電波吸収量を示せばよい。電波吸収性能は入射角に
も依存するので一意的に決定することは出来ないが、30
MHzにおいて15dB以上の反射減衰量は必要である。放射
雑音評価用電波暗室に使用している複合型電波吸収体
（フェライトタイルと導電性発泡スチロールの組み合わ
せ）は周波数分担型の動作機構であるから、現状の性能
では低周波側の吸収を分担するフェライトを改善しなけ
ればならない。The suitability of the test site for radiation noise evaluation is determined by the deviation from the theoretical site attenuation, and the allowable deviation is 30 MHz.
The theoretical value is within ± 4 dB within the range of ~ 1 GHz. The radio wave absorber used in such an anechoic chamber only needs to exhibit a radio wave absorption of a certain value or more in the entire frequency range. Since the radio wave absorption performance also depends on the angle of incidence, it cannot be determined uniquely, but 30
A return loss of 15 dB or more at MHz is required. The composite electromagnetic wave absorber (combination of ferrite tile and conductive styrofoam) used in the anechoic chamber for radiated noise evaluation is a frequency-sharing type operating mechanism. Must be improved.
フェライトの吸収性能を改善するには、初透磁率の高
い材質を開発すると共にタイルとして施工した時に初透
磁率を維持できる手段を講ずる必要がある。In order to improve the absorption performance of ferrite, it is necessary to develop a material having a high initial permeability and take measures to maintain the initial permeability when the tile is constructed.
第２図はフェライトの透磁率μと周波数ｆの関係を示
し、透磁率μの実数部はおおむねある周波数まで一定
で、それ以上の周波数ではしだいに低下し、又虚数部は
図示のごとき山形特性を示し、実数部と虚数部が周波数
ｆに対し共に低下傾向を示す図のＡ又はＢの周波数帯で
優れた電波吸収特性が得られる。そして、透磁率（実数
部）の小さなフェライトは図のＡで示す高い周波数帯で
優れた電波吸収特性を示し、透磁率（実数部）の大きな
フェライトは図のＢで示すごどく低い周波数帯で優れた
電波吸収特性を示す。FIG. 2 shows the relationship between the magnetic permeability μ of the ferrite and the frequency f. The real part of the magnetic permeability μ is generally constant up to a certain frequency, gradually decreases at frequencies higher than that, and the imaginary part is the peak-shaped characteristic as shown. , And excellent radio wave absorption characteristics can be obtained in the frequency band A or B in which both the real part and the imaginary part tend to decrease with respect to the frequency f. A ferrite having a small magnetic permeability (real part) exhibits excellent electromagnetic wave absorption characteristics in a high frequency band shown by A in the figure, and a ferrite having a large magnetic permeability (real part) has a very low frequency band shown in B in the figure. Shows excellent radio wave absorption characteristics.
従って、低周波数帯での吸収特性を改善するには、透
磁率の大きなフェライトを用いる必要があるこどがわか
る。Therefore, it is understood that it is necessary to use ferrite having a large magnetic permeability in order to improve the absorption characteristics in a low frequency band.
しかしながら、フェライトは、所定の大きさのタイル
状に整形されたものを貼り合せて用いるので、貼り合せ
る際に隣のタイルとの間に隙間があると、隙間のため
に、実効的な透磁率は大きく低下してしまう。従釆の電
波吸収体ではタイルを焼結後加工せずに貼り付けている
が、この工法ではタイル間の接触面積が少なく不安定な
ためフェライト面の磁気抵抗が増加して低周波側の吸収
性能を損ねる。タイル間の接触を改善する方法として大
きさの揃った正（長）方形に機械加工する方法がある
が、この方法では加工に多大の時間がかかり、品質管理
が困難である。特にタイルの４辺を全て機械加工して完
全な方形にして、隣接タイルとの隙間をなくすことは非
常に困難である。However, since ferrite is used by bonding tiles shaped into tiles of a predetermined size, if there is a gap between adjacent tiles at the time of bonding, effective magnetic permeability due to the gap Is greatly reduced. In the conventional radio wave absorber, the tile is pasted without processing after sintering, but in this method, the contact area between tiles is small and unstable, so the magnetic resistance of the ferrite surface increases and the absorption on the low frequency side Impairs performance. As a method of improving the contact between the tiles, there is a method of machining into a regular (long) square having a uniform size. However, this method requires a great deal of time for processing, and quality control is difficult. In particular, it is very difficult to machine all four sides of a tile to a perfect square to eliminate gaps between adjacent tiles.
（発明が解決しようとする課題） 本発明は簡単な機械加工によるフェライトを用いて、
フェライト素材が本来もつ高い透磁率を減殺せずに低周
波数帯での吸収特性の優れた電波暗室を提供することを
目的とする。(Problems to be solved by the invention) The present invention uses ferrite by simple machining,
It is an object of the present invention to provide an anechoic chamber having excellent absorption characteristics in a low frequency band without reducing a high magnetic permeability inherent in a ferrite material.
（課題を解決するための手段） 本発明の特徴は、天井面及び壁面にフェライトを含む
タイルを貼り合せた電波暗室において、各タイルは１組
の対向する平行辺のみが精密に且つ平行に機械加工さ
れ、該辺が隣接タイルの精密に且つ平行に機械加工され
た辺と結合することにより、該辺と直交する方向（Ｎ）
に高い透磁率をもつごどく磁気的に連続して貼り合さ
れ、天井面のタイルは、部屋の長手軸に平行な方向が前
記方向（Ｎ）と一致するごとく貼り合され、 壁面のタ
イルは、水平面と平行な方向が前記方向（Ｎ）と一致す
るごとく貼り合される電波暗室にある。(Means for Solving the Problems) A feature of the present invention is that, in an anechoic chamber in which tiles containing ferrite are stuck on a ceiling surface and a wall surface, each tile has a machine in which only one set of opposed parallel sides is precisely and parallel. Direction (N) orthogonal to the side that has been machined and that side is joined to the precisely and parallel machined side of the adjacent tile
The tiles on the ceiling surface are laminated so that the direction parallel to the longitudinal axis of the room coincides with the direction (N), and the tiles on the wall surface are , In a anechoic chamber that is bonded so that the direction parallel to the horizontal plane coincides with the direction (N).
（作用） タイルが１組の対向平行辺のみが機械加工されて、機
械加工された辺が隣接タイルの当該辺と結合するよう
に、次々と貼り合される。従って、タイルの当該辺の間
の隙間はほとんどなく、該辺と直交する方向には、タイ
ルは磁気的に連続で大きな透磁率をもつ。(Operation) Only one set of opposing parallel sides of the tile is machined, and the tiles are bonded one after another such that the machined side is connected to the side of the adjacent tile. Therefore, there is almost no gap between the sides of the tile, and in the direction orthogonal to the side, the tile is magnetically continuous and has high magnetic permeability.
そして、電波暗室の天井及び壁面は、特定のひとつの
方向にのみ高い透磁率をもてば高い吸収特性が得られる
ので、該方向をタイルが高い透磁率をもつ方向と一致さ
せる。The ceiling and wall surfaces of the anechoic chamber have high magnetic permeability only in one specific direction, so that high absorption characteristics can be obtained. Therefore, the direction is made to coincide with the direction in which the tile has high magnetic permeability.
以上の構成により、タイルの全辺を機械加工しなくて
も、実効的に高い透磁率をもつタイルにより低周波吸収
特性の優れた電波暗室が得られる。According to the above configuration, an anechoic chamber excellent in low-frequency absorption characteristics can be obtained by a tile having an effective high magnetic permeability without machining all sides of the tile.
（実施例） 放射雑音評価用電波暗室にダイポール・アンテナを置
いて壁面からの反射と測定誤差の関係を検討してみる
と、偏波面により寄与が異なることが判かる。この関係
を偏波面に応じて定性的に示すと、 水平偏波：天井＞前後の壁＞側壁 垂直偏波：側壁≒前後の壁＞天井 以上のようになり、水平偏波では天井、垂直偏波では周
囲の壁面の吸収性能が測定精度に影響する。特定の偏波
に対する吸収性能を改善するために本発明では、磁束が
通過する方向の透磁率（磁気抵抗）を改善する。電波暗
室用のタイルにこの方法を当てはめ、向かい合う２辺を
平行に機械加工して磁気抵抗を低減することにより性能
維持を図る。(Example) When a dipole antenna is placed in an anechoic chamber for radiation noise evaluation and the relationship between the reflection from the wall surface and the measurement error is examined, it can be seen that the contribution differs depending on the polarization plane. This relationship is qualitatively expressed according to the plane of polarization. Horizontal polarization: ceiling> front and rear walls> side walls Vertical polarization: side wall ≒ front and rear walls> ceiling The horizontal polarization: ceiling and vertical polarization For waves, the absorption performance of the surrounding wall affects the measurement accuracy. In the present invention, the magnetic permeability (magnetic resistance) in the direction in which the magnetic flux passes is improved in order to improve the absorption performance for a specific polarization. This method is applied to tiles for anechoic chambers, and two opposing sides are machined in parallel to reduce magnetic resistance to maintain performance.
第１図は本発明による電波暗室10を示し、暗室の長手
方向Ｎに沿って供試体（又は送信アンテナ）と受信アン
テナが配置されるものとする。フェライトの透磁率は、
水平偏波の場合には天井面12のフェライトのＮ方向の透
磁率が高いこどが好ましく、又垂直偏波の場合には壁面
14,16（及び対向壁面）の水平面と平行な方向の透磁率
が高いことが好ましい。電波暗室は水平偏波及び垂直偏
波の両方に優れた特性をもつ必要があるので、天井及び
４面の壁面のタイルは全てＮ方向及び水平面と平行な方
向の透磁率が大きくなるように貼ればよい。FIG. 1 shows an anechoic chamber 10 according to the present invention, in which a specimen (or a transmitting antenna) and a receiving antenna are arranged along a longitudinal direction N of the anechoic chamber. The permeability of ferrite is
In the case of horizontal polarization, it is preferable that the ferrite of the ceiling surface 12 has a high magnetic permeability in the N direction.
It is preferable that the magnetic permeability in the direction parallel to the horizontal plane of the 14, 16 (and the opposed wall surfaces) is high. Since the anechoic chamber must have excellent characteristics for both horizontal and vertical polarization, all the tiles on the ceiling and the four wall surfaces are pasted so that the magnetic permeability in the N direction and the direction parallel to the horizontal plane is large. I just need.
フェライトタイルは２組の平行辺を有する方形で、そ
れらのうちの１組の平行辺20a,20bのみを精密に平行に
機械加工する。他の１組の平行辺は機械加工をしなくて
もよい。The ferrite tile is a square with two sets of parallel sides, of which only one set of parallel sides 20a, 20b is machined precisely parallel. The other set of parallel sides may not be machined.
フェライトは、機械加工をした精密平行辺が相互に隣
接するごとく、天井及び各壁面に貼り合せる。従って、
Ｎ方向（又は水平面と平行な方向）には実質的に隙間な
くフェライトが貼られ、Ｎ方向に大きな透磁率が得られ
る。Ｎ方向と直交するＭ方向ではフェライトタイルの間
にわずかな隙間があり（図では隙間が拡大されてい
る）、Ｍ方向の透磁率は小さいが、電波暗室の吸収特性
には影響はない。The ferrite is bonded to the ceiling and each wall, as if the machined precision parallel sides were adjacent to each other. Therefore,
Ferrite is adhered in the N direction (or a direction parallel to the horizontal plane) with substantially no gap, and a large magnetic permeability is obtained in the N direction. In the M direction perpendicular to the N direction, there is a slight gap between the ferrite tiles (the gap is enlarged in the figure), and although the magnetic permeability in the M direction is small, it does not affect the absorption characteristics of the anechoic chamber.
（発明の効果） 以上のごとく、一方の平行辺のみを機械加工した簡単
なフェライトタイルを用いて低周波帯での水平偏波及び
垂直偏波の吸収特性の優れた電波暗室を得るこどがで
き、従って、10m法以上の大型の電波暗室に適用して有
用である。なお方形以外の形のタイル（例えば六角形）
でも、１組の対向平行辺のみを機械加工することにより
本発明を適用することができる。(Effects of the Invention) As described above, it is possible to obtain an anechoic chamber excellent in horizontal and vertical polarization absorption characteristics in a low frequency band using a simple ferrite tile in which only one parallel side is machined. Yes, it is useful when applied to large anechoic chambers of 10m or more. Note that tiles other than square (for example, hexagonal)
However, the present invention can be applied by machining only one set of opposing parallel sides.
第１図は本発明による電波暗室の構成例、 第２図はフェライトの透磁率と周波数の関係を示す図で
ある。 10:電波暗室,12:天井,14,16:壁。FIG. 1 is a diagram showing a configuration example of an anechoic chamber according to the present invention, and FIG. 2 is a diagram showing the relationship between the magnetic permeability and frequency of ferrite. 10: Anechoic chamber, 12: Ceiling, 14, 16: Wall.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 市原 謙一 東京都中央区日本橋１丁目13番１号 テ ィーディーケイ株式会社内 (56)参考文献 実開 昭53−149506（ＪＰ，Ｕ) 実公 昭61−33678（ＪＰ，Ｙ２) (58)調査した分野(Int.Cl.6，ＤＢ名) H05K 9/00────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kenichi Ichihara 1-1-13 Nihonbashi, Chuo-ku, Tokyo Inside TDK Corporation (56) References Real Opening Sho 53-149506 (JP, U) Shoichi Sho 61 −33678 (JP, Y2) (58) Fields investigated (Int. Cl. 6 , DB name) H05K 9/00
Claims (1)
を貼り合せた電波暗室において、 各タイルは１組の対向する平行辺のみが精密に且つ平行
に機械加工され、該辺が隣接タイルの精密に且つ平行に
機械加工された辺と結合することにより、該辺と直交す
る方向（Ｎ）に高い透磁率をもつごとく磁気的に連続し
て貼り合され、 天井面のタイルは、部屋の長手軸に平行な方向が前記方
向（Ｎ）と一致するごとく貼り合され、 壁面のタイルは、水平面と平行な方向が前記方向（Ｎ）
と一致するごとく貼り合されることを特徴とする電波暗
室。In an anechoic chamber in which tiles containing ferrite are stuck to a ceiling surface and a wall surface, each tile is machined precisely and parallel to only one set of opposing parallel sides, and the sides are precision machined to adjacent tiles. And in parallel with the machined side, it is magnetically continuously bonded so as to have a high magnetic permeability in the direction (N) perpendicular to the side, and the tile on the ceiling surface is formed in the longitudinal direction of the room. The tiles on the wall surface are bonded so that the direction parallel to the axis coincides with the direction (N), and the direction parallel to the horizontal plane is the direction (N).
An anechoic chamber characterized by being bonded as if it matches.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1158433A JP2827286B2 (en) | 1989-06-22 | 1989-06-22 | Anechoic chamber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1158433A JP2827286B2 (en) | 1989-06-22 | 1989-06-22 | Anechoic chamber |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0324792A JPH0324792A (en) | 1991-02-01 |
| JP2827286B2 true JP2827286B2 (en) | 1998-11-25 |
Family
ID=15671657
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1158433A Expired - Lifetime JP2827286B2 (en) | 1989-06-22 | 1989-06-22 | Anechoic chamber |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2827286B2 (en) |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5552717Y2 (en) * | 1977-04-28 | 1980-12-06 | ||
| JPS6133678U (en) * | 1984-07-31 | 1986-02-28 | 吉誠 田窪 | Hopper structure in rotary plastic pellet sorter |
-
1989
- 1989-06-22 JP JP1158433A patent/JP2827286B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0324792A (en) | 1991-02-01 |
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