JPH07120983B2 - Anechoic chamber - Google Patents
Anechoic chamberInfo
- Publication number
- JPH07120983B2 JPH07120983B2 JP62110842A JP11084287A JPH07120983B2 JP H07120983 B2 JPH07120983 B2 JP H07120983B2 JP 62110842 A JP62110842 A JP 62110842A JP 11084287 A JP11084287 A JP 11084287A JP H07120983 B2 JPH07120983 B2 JP H07120983B2
- Authority
- JP
- Japan
- Prior art keywords
- anechoic chamber
- antenna
- shows
- length
- respect
- 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 - Fee Related
Links
- 239000006096 absorbing agent Substances 0.000 claims description 12
- 230000005540 biological transmission Effects 0.000 claims description 3
- 230000002093 peripheral effect Effects 0.000 claims 1
- 238000005192 partition Methods 0.000 description 8
- 230000005684 electric field Effects 0.000 description 7
- 238000005259 measurement Methods 0.000 description 6
- 239000004020 conductor Substances 0.000 description 4
- 230000035945 sensitivity Effects 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229920006328 Styrofoam Polymers 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 238000000638 solvent extraction Methods 0.000 description 1
- 239000008261 styrofoam Substances 0.000 description 1
Landscapes
- Monitoring And Testing Of Transmission In General (AREA)
- 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、特に広い周波数帯域にわたっ
て屋外と同等の電波吸収特性を与える電波暗室に関す
る。TECHNICAL FIELD The present invention relates to an anechoic chamber, and more particularly to an anechoic chamber that provides an electromagnetic wave absorption characteristic equivalent to that of outdoors over a wide frequency band.
（従来の技術） 電波暗室は各種電波機器の特性試験を屋内で行なう目的
で広く用いられており、閉じた部屋の内面に電波吸収体
をもうけた構造を有する。(Prior Art) An anechoic chamber is widely used for the purpose of performing characteristic tests of various radio equipment indoors, and has a structure in which an electromagnetic wave absorber is provided on the inner surface of a closed room.
電波暗室自身の電波吸収特性の試験は例えば次のように
行なわれる。The test of the electromagnetic wave absorption characteristics of the anechoic chamber itself is performed as follows, for example.
電波暗室内の所定の場所に広帯域の送信アンテナ（例え
ばバイコニカルアンテナ）と受信アンテナを所定の間隔
で配置し、受信アンテナに接続される受信機は受信感度
の最大値をとるように設定する。送信周波数を掃引した
ときの受信感度を各周波数について測定し、該受信感度
が屋外での測定値に対して、一定の範囲（例えば±4d
B）にあれば合格とする。測定はアンテナの偏波面や高
さを変えて数回行なわれ、全ての測定値が一定の範囲に
あるときに、当該電波暗室は合格となる。A wideband transmission antenna (for example, a biconical antenna) and a reception antenna are arranged at a predetermined location in a radio wave anechoic chamber at predetermined intervals, and a receiver connected to the reception antenna is set to have a maximum reception sensitivity. The reception sensitivity when the transmission frequency is swept is measured for each frequency, and the reception sensitivity is within a certain range (for example, ± 4d
If B), pass. The measurement is performed several times by changing the plane of polarization and height of the antenna, and the anechoic chamber passes when all the measured values are within a certain range.
（発明が解決しようとする問題点） 第２図は従来の電波暗室の測定結果の例を示し、横軸は
周波数、縦軸は減衰量（１目盛10dB）を示す。図の基準
曲線A0は屋外での試験結果を示す（アンテナ自身が周波
数特性をもつ為フラットにはならない）。曲線A1とA2は
A0に対する±4dBの曲線である。曲線a,b,c,dは測定結果
で各々送信アンテナをターンテーブルの回転により50cm
づつ前後左右に受信アンテナに対して移動させたときの
特性を示す。図から明らかなように、約60MHz付近のＰ
の部分で曲線（ａ）が基準範囲を越えており、従ってこ
の電波暗室は不合格である。(Problems to be Solved by the Invention) FIG. 2 shows an example of measurement results of a conventional anechoic chamber, in which the horizontal axis represents frequency and the vertical axis represents attenuation (1 scale 10 dB). The reference curve A 0 in the figure shows the test results outdoors (the antenna itself does not become flat because it has frequency characteristics). Curves A 1 and A 2
It is a curve of ± 4 dB with respect to A 0 . Curves a, b, c, and d are the measurement results.
The characteristics are shown when the antenna is moved forward, backward, leftward, and rightward with respect to the receiving antenna. As is clear from the figure, P around 60MHz
The curve (a) exceeds the reference range in the area of, and therefore this anechoic chamber is rejected.
従来は、不合格の場合は電波吸収体を部分的に追加する
などして特性を基準範囲内におさめる手法が用いられて
いたが、作業工数が大きいうえに必ずしも所望の結果が
得られるとは限らなかった。Conventionally, in the case of failure, a method of keeping the characteristics within the reference range by partially adding a radio wave absorber has been used, but it is not always possible to obtain the desired result in addition to the large number of work steps. Not limited.
本発明は上記問題点を解決し、常に許容範囲内の特性を
示す電波暗室を提供することを目的とする。It is an object of the present invention to solve the above problems and provide an anechoic chamber that always exhibits a characteristic within an allowable range.
（問題点を解決するための手段） 上記目的を達成するための本発明の特徴は、少なくとも
壁面と天井面に電波吸収体をもうけた閉じた形状の電波
暗室において、該電波暗室内にもうけられる送信源と受
信源を結ぶ直線から電波暗室の電磁気的壁面までの伝播
長が前記直線に関し少なく共一部が非対称である電波暗
室にある。(Means for Solving the Problems) The feature of the present invention for achieving the above object is to provide an anechoic chamber having a closed shape in which at least a wall surface and a ceiling surface are provided with an electromagnetic wave absorber, and the anechoic chamber is provided therein. In the anechoic chamber where the propagation length from the straight line connecting the transmitting source and the receiving source to the electromagnetic wall of the anechoic chamber is small with respect to the straight line and a part of the propagation length is asymmetric.
（発明の構成と作用） 電波暗室の特性改善の資料として、本発明者は電波暗室
内の電界分布を詳細に調査した。結果の一部を第３図に
示す。ここで上段は本発明の測定結果であり、比較の為
に下段に従来の電波暗室の特性を示す。(Structure and Action of the Invention) As a material for improving the characteristics of the anechoic chamber, the present inventor investigated the electric field distribution in the anechoic chamber in detail. Some of the results are shown in FIG. Here, the upper part shows the measurement results of the present invention, and the lower part shows the characteristics of the conventional anechoic chamber for comparison.
第３図は長さ10.5m,幅7.5mの電波暗室の図示の位置にタ
ーンテーブルを置き、その上の床からの高さ0.1mの点
で、ターンテーブルの中心から50cmだけ受信アンテナ側
に送信アンテナTxを置き、送信アンテタから3m離れた点
で床から1mの高さに受信アンテナRxを置いたときの電界
分布を示したものである。第３図（イ）は電波暗室がTx
とRxアンテナを結ぶ線に対して対称なときの電界分布
で、（ロ）は図示されたような非対称性が与えられた場
合の電界分布である。なお両アンテナTxとRxは部屋の中
心線上に置き、測定周波数は62.5MHzである。図の曲線
は等電界線で2dB間隔で図示してある。なお、図のＡの
部分は部屋の内面全体にはられた電波吸収体を示し、図
のＢの部分は非対称とするために部分的にはられた電波
吸収体を示す。Figure 3 shows a turntable placed at the position shown in the anechoic chamber with a length of 10.5m and a width of 7.5m, and at a height of 0.1m above the floor, 50cm from the center of the turntable to the receiving antenna side. The figure shows the electric field distribution when the transmitting antenna T x is placed and the receiving antenna R x is placed at a height of 1 m from the floor at a point 3 m away from the transmitting antheta. In Fig. 3 (a), the anechoic chamber is T x
Is the electric field distribution when it is symmetric with respect to the line connecting the R x antenna, and (b) is the electric field distribution when the asymmetry shown in the figure is given. Note the antennas T x and R x is placed on the center line of the room, the measurement frequency is 62.5 MHz. The curves in the figure are shown with isoelectric lines at 2 dB intervals. The portion A in the figure shows the electromagnetic wave absorber that is placed on the entire inner surface of the room, and the portion B in the figure shows the electromagnetic wave absorber that is partially placed in order to make it asymmetric.
第３図から明らかなように、電界強度はアンテナTxとRx
の中心を結ぶ線に対して対称であることが推測される。
このことから、電波が壁面で反射し、室内に定在波が存
在することが推測される。従って、本発明では、暗室内
の対称な定在波を解消するために、暗室の寸法を非対称
として中心線の左右で共振周波数を変ることにより定在
波の発生を抑制する。As apparent from FIG. 3, the field strength antenna T x and R x
It is presumed that it is symmetric with respect to the line connecting the centers of.
From this, it can be inferred that the radio wave is reflected by the wall surface and a standing wave exists in the room. Therefore, in the present invention, in order to eliminate the symmetrical standing wave in the dark room, the size of the dark room is made asymmetric and the resonance frequency is changed on the left and right of the center line to suppress the occurrence of the standing wave.
第１図は本発明による電波暗室10の構造例を示し、12は
実質的に導電性を有する外壁、14は暗室内の一部を仕切
る為の導体による仕切壁、16は壁の内面にもうけられる
電波吸収体、Txは送信アンテナ、Rxは受信アンテナであ
る。アンテナTxとRxの中心を結ぶ線が、図示のごとく、
部屋の中心線にほぼ一致するごとくアンテナが配置され
る。仕切壁14と外壁12の間の間隔は約45cmである。な
お、暗室の床面は導体とし、天井の内面には電波吸収体
がもうけられるものとする。FIG. 1 shows an example of the structure of an anechoic chamber 10 according to the present invention. 12 is an outer wall having substantially conductivity, 14 is a partition wall made of a conductor for partitioning a part of the dark room, and 16 is an inner surface of the wall. wave absorber that is, T x is the transmitting antenna, R x is the receive antenna. The line connecting the centers of the antennas T x and R x is
The antennas are arranged so that they almost coincide with the center line of the room. The distance between the partition wall 14 and the outer wall 12 is about 45 cm. In addition, the floor of the dark room shall be a conductor, and the electromagnetic wave absorber shall be provided on the inner surface of the ceiling.
図示の構造で、仕切壁14の存在により、アンテナは対称
な部屋の中心に置かれるにもかかわらず、アンテナを結
ぶ中心線と電磁気的壁面（ほぼ電波吸収体16の表面）と
の間の伝播長は前記中心線に対し非対称となる。従って
定在波の対称性はくずれる。In the structure shown in the figure, due to the presence of the partition wall 14, although the antenna is placed in the center of a symmetrical room, the propagation between the center line connecting the antennas and the electromagnetic wall surface (approximately the surface of the electromagnetic wave absorber 16). The length is asymmetric with respect to the center line. Therefore, the symmetry of the standing wave is broken.
第４図は電波吸収体の16の構造例で、発泡スチロールの
ビーズ上にカーボンを塗布し、特性インピーダンスが10
0Ω/cm〜500Ω/cmで、くさび形状の部材16aがフェライ
トタイル16bの上にもうけられる。フェライトタイル16b
の裏には導体16cがもうけられるが、この導体は部屋の
外壁又は仕切壁により提供される。Fig. 4 shows 16 structural examples of electromagnetic wave absorbers, in which carbon is coated on Styrofoam beads and the characteristic impedance is 10
A wedge-shaped member 16a is placed on the ferrite tile 16b at 0 Ω / cm to 500 Ω / cm. Ferrite tile 16b
A conductor 16c is provided on the back side of the room, and this conductor is provided by the outer wall or partition wall of the room.
第５図は本発明による電波暗室の特性を示し、測定条件
は第２図の場合と同じである。図示のごとく、曲線ａ〜
ｄの全てが許容範囲であるA1とA2の間に入っている。FIG. 5 shows the characteristics of the anechoic chamber according to the present invention, and the measurement conditions are the same as in the case of FIG. As shown in the figure, the curves a to
All of d fall within the acceptable range of A 1 and A 2 .
第３図と第５図を対比してみると、第３図の受信アンテ
ナRxの付近での電界は、従来の技術（下段）では−16dB
であるのに対し、本発明（上段）では−14dBとなってい
る。従って、第２図の60dB付近で規格外となったＰの部
分は第５図では改善されて規格内となる。Comparing FIG. 3 and FIG. 5, the electric field in the vicinity of the receiving antenna R x in FIG. 3 is −16 dB in the conventional technique (lower stage).
On the other hand, in the present invention (upper row), it is −14 dB. Therefore, the portion of P which is out of the standard in the vicinity of 60 dB in FIG. 2 is improved in FIG.
仕切壁14は必ずしも部屋の半周にわたってもうける必要
はなく、壁面の周囲の長さの10％〜80％にわたってもう
ければ十分である。又、許容範囲が±4dBである場合に
は、仕切壁は側壁面全体にもうける必要はなく、床面か
ら天井面までの長さの1/20〜1/4にわたってもうければ
十分である。The partition wall 14 does not necessarily have to be provided over a half circumference of the room, but it is sufficient if it is provided over 10% to 80% of the perimeter of the wall surface. Also, when the allowable range is ± 4 dB, it is not necessary to provide the partition wall on the entire side wall surface, and it is sufficient if the partition wall covers 1/20 to 1/4 of the length from the floor surface to the ceiling surface.
（発明の効果） 以上のごとく、本発明よると、簡単な構造で、屋外と同
等の特性の電波暗室を提供することができる。(Effects of the Invention) As described above, according to the present invention, it is possible to provide an anechoic chamber having a simple structure and the same characteristics as outdoors.
第１図は本発明による電波暗室の構造例、第２図は従来
の電波暗室の特性例、第３図は従来の電波暗室の電界分
布と非対称性を与えた場合の電界分布の比較を示す図、
第４図は電波吸収体の構造例、第５図は本発明による電
波暗室の特性例である。 10;電波暗室、12;外壁、 14;仕切壁、16;電波吸収体、 Tx;送信アンテナ、Rx;受信アンテナ。FIG. 1 shows a structural example of an anechoic chamber according to the present invention, FIG. 2 shows a characteristic example of a conventional anechoic chamber, and FIG. 3 shows a comparison of the electric field distribution of the conventional anechoic chamber and the electric field distribution when asymmetry is applied. Figure,
FIG. 4 shows an example of the structure of the electromagnetic wave absorber, and FIG. 5 shows an example of characteristics of the anechoic chamber according to the present invention. 10: anechoic chamber, 12: outer wall, 14: partition wall, 16: electromagnetic wave absorber, T x ; transmitting antenna, R x ; receiving antenna.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 渡辺 隆志 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 (72)発明者 勝俣 正史 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 特開 昭57−97700（ＪＰ，Ａ) ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Watanabe 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDC Corporation (72) Masafumi Katsumata 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDC Incorporated (56) References JP-A-57-97700 (JP, A)
Claims (3)
うけた閉じた形状の電波暗室において、 該電波暗室内にもうけられる送信源と受信源を結ぶ直線
から電波暗室の電磁気的壁面までの伝播長が前記直線に
関し少なく共一部が非対称であることを特徴とする電波
暗室。1. In a closed anechoic chamber having an electromagnetic wave absorber on at least a wall surface and a ceiling surface, propagation from a straight line connecting a transmission source and a reception source provided in the anechoic chamber to an electromagnetic wall surface of the anechoic chamber. An anechoic chamber characterized in that the length is small with respect to the straight line and a part thereof is asymmetric.
20〜1/4の範囲で前記直線に関し非対称であることを特
徴とする特許請求の範囲第１項記載の電波暗室。2. The propagation length is 1 / of the length from the floor surface to the ceiling
The anechoic chamber according to claim 1, wherein the anechoic chamber is asymmetric with respect to the straight line in the range of 20 to 1/4.
％の範囲で前記直線に関し非対称であることを特徴とす
る特許請求の範囲第１項記載の電波暗室。3. The propagation length is 10% to 80% of the peripheral length of the wall surface.
The anechoic chamber according to claim 1, wherein the anechoic chamber is asymmetric with respect to the straight line in the range of%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62110842A JPH07120983B2 (en) | 1987-05-08 | 1987-05-08 | Anechoic chamber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62110842A JPH07120983B2 (en) | 1987-05-08 | 1987-05-08 | Anechoic chamber |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63276932A JPS63276932A (en) | 1988-11-15 |
| JPH07120983B2 true JPH07120983B2 (en) | 1995-12-20 |
Family
ID=14546045
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62110842A Expired - Fee Related JPH07120983B2 (en) | 1987-05-08 | 1987-05-08 | Anechoic chamber |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07120983B2 (en) |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5797700A (en) * | 1980-12-11 | 1982-06-17 | Emaason Ando Kamingu Japan Kk | Radio wave no echo chamber |
-
1987
- 1987-05-08 JP JP62110842A patent/JPH07120983B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63276932A (en) | 1988-11-15 |
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|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |