JPH04122392U - anechoic chamber - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an anechoic chamber with low construction cost and easy handling. [Structure] A base 6 containing a lifting/swivel pulley and an electric motor of the antenna lifting device is placed in the ceiling of the anechoic chamber 1.
An FRP pole 7 is suspended from the base through an opening in a shield material on the ceiling. The bottom end of the pole is off the floor. An antenna unit 9 is provided on the pole so that it can be raised and lowered. [Effect] Even if there are parts of the base that tend to reflect radio waves, there is no need to dig a pit in the ground plane, and the floor can be made flat, reducing construction costs. Since there are fewer moving objects, the efficiency of converting a complete anechoic chamber that can be used commonly for EMI measurement is improved. Since there are fewer things occupying the floor, people can move safely and objects can be easily moved.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

The present invention relates to a radio anechoic chamber, and in particular, to an antenna lifting/lowering rotation device placed in a radio anechoic chamber. Regarding the installation structure.

0002

[Conventional technology]

In the anechoic chamber used for interference measurement tests of electronic devices, the floor structure of the shielded chamber is There is a known structure in which a ground plane is used and a radio wave absorber is installed on the wall other than the floor. It is. Such an anechoic chamber has almost the same radio wave propagation characteristics as an open site. It is called an EMI measurement anechoic chamber. For this purpose, we evaluate the characteristics of the antenna. In such cases, install radio wave absorbers on the entire wall surface including the floor of the shield room to create a free space. A so-called completely anechoic chamber is used, which has radio wave propagation characteristics that are almost the same.

0003 In EMI measurements, the equipment under test and the antenna are placed on the ground plane in a dark room at a predetermined distance ( 3m or 10m), and the height of the antenna is continuously set from 1m to 4m. Change to Then, a composite wave of the direct interference wave and the reflected wave from the ground plane. is received by the antenna, stop moving the antenna at the position where the noise level is maximum, After that, rotate the turntable on which the equipment under test is placed, and Stop the turntable in the opposite direction and measure the noise level in the required frequency band. On this occasion , there are two types of antennas: horizontal and vertical (horizontal/vertical polarization). Take data.

0004 By the way, when measuring EMI, you need to use a base and an FRP pole placed on the base. An antenna lifting/lowering rotating device (hereinafter simply referred to as the device) is used, It is fixed to an antenna unit installed on a pole that can be raised and lowered. The antenna unit , a drive section consisting of an electric motor and drive pulley installed on the base moves the belt through the belt. It is lifted and lowered. The drive unit also rotates the antenna via a belt. The device weighs The weight is about 50 kg, and casters are sometimes attached to the base to make it mobile.

[0005] In the EMI measurement anechoic chamber, there is a lot of reflection of radio waves from the drive unit installed on the base of the device. or if you want to avoid the existence of the base itself, dig into the floor of the shield room. Make a depression (for example, 1.2m square and about 0.5m deep) surrounded by shielding material. A floor structure in which the base is housed in a recess, with only the equipment pole protruding from the ground plane. is used.

[0006] In the case of a completely anechoic chamber used for EMI measurement, the floor of the shielded room must be The wedge-shaped foam radio wave absorber installed in It is exposed as a ground plane. Then, each time the floor conversion work is performed, the equipment is Carrying in and out. In addition, we have installed a completely anechoic chamber with a tile-shaped ferrite absorber installed on the floor of the shield room. , when converting to EMI measurement, and when converting to the original darkroom, place it on the floor. Move devices placed on the floor, such as devices (bases covered with radio wave absorbers), one by one. Laying or removing a ground plane member (metal plate) on top of the ferrite absorber are doing.

[0007]

[Problem that the idea aims to solve]

As mentioned above, in an anechoic chamber where the antenna lifting/lowering device is placed on the floor, When creating a recess for storing the base, do not dig into the ground or raise the foundation sufficiently high. This poses a problem in that construction costs are high. On the other hand, EMI In the shared anechoic chamber, the base is several times the cross-sectional area of the pole (approximately 1 meter square). This poses the problem of getting in the way when people move around the room, and it is difficult to access the equipment in and out of the darkroom. There is a problem in that it is difficult to handle because it has to be moved often in a dark room. In addition, when performing maintenance inspections, operators must enter a dark room or pick out equipment. There is a need for The purpose of this invention is to provide an anechoic chamber that is inexpensive to construct and easy to handle. It is in.

[0008]

[Means to solve the problem]

In the present invention, an antenna lifting/lowering/swivel device is installed on the ceiling of the anechoic chamber. in the shield room Install the base of the antenna lifting/lowering swivel device under the ceiling and pass it through the opening in the ceiling shielding material. An FRP pole placed on a base is hung down. Also, keep the bottom end of the pole off the floor. I'll keep it.

[0009]

[Effect]

In this invention, the base of the antenna lifting/lowering rotation device is placed in the ceiling of the shield room. Since the module is suspended from the base into the shield chamber, various types of problems in the anechoic chamber can be You can work efficiently.

0010

【Example】

The present invention will be explained below with reference to examples. Referring to Figure 1, the illustrated anechoic chamber has five sides other than the floor of shield room 1 (in the figure, the floor EMI meter with wedge-shaped radio wave absorbers 2 installed on both vertical walls and three sides of the ceiling (shown) It is an electromagnetic wave anechoic chamber. The floor of shield room 1 is a ground plane, and the test machine is placed on the floor. A turntable 3 on which a container 4 is placed and rotates is arranged. to turntable 3 has a built-in drive mechanism. at a predetermined distance (3m or 10m) from the location of turntable 3. A square hole-shaped opening is formed in the corresponding ceiling through the ceiling surface and the radio wave absorber 2. A small shield room 5 is provided in the ceiling around the opening.

[0011] The antenna lifting/lowering turning device is equipped with a base 6, and the base 6 is located inside the small shield room 5. It is fixed to the top surface (ceiling surface). A pole 7 extending downward is erected on the base 6. A drive unit 8 consisting of a drive pulley, an electric motor, etc. is arranged on the base 6. . Pole 7 is a rectangular cylinder made of FRP, extends vertically through the opening, and serves as a shield. It has reached room 1. The dimensions of the opening are, for example, about 100 mm x 100 mm, Normally, there is little risk that the shield between shield room 1 and small shield room 5 will be a problem. do not have. The small shield chamber 5 has a slit (for example, for belt insertion, wiring insertion, etc.). It is necessary to ensure shielding at the opening for pole 7 for reasons such as In the case where the pole 7 is ), install a shield material in the shape of a rectangular tray with a slit for belt insertion on the inner bottom. do it. In addition, a slit for belt insertion is provided on the ceiling of shield room 1, and pole 7 may be directly fixed to the ceiling of the shield room 1.

0012 The length of the pole 7 is such that the antenna unit 9 fitted on the pole 7 is In the range of 1m to 4m from the floor of the The dimensions are set so that it can be raised and lowered. Antenna 10 attached to antenna unit 9 is swiveled by a drive and adjusted to receive horizontally or vertically polarized waves. It will be done.

[0013] As mentioned above, the antenna lift/swivel device is placed above the ground plane. This allows people to come and go more freely within the anechoic chamber than before, and the equipment under test 4 cannot be brought in and out. It's easy. An anechoic chamber, whether built indoors or outdoors, has a ceiling that absorbs radio waves. In order to install Body 2, the ceiling is made sturdy and a work space is secured in the ceiling. Therefore, maintenance and inspection of the drive unit 8 in the small shield chamber 5 can be easily carried out.

[0014] FIG. 2 shows another embodiment of a completely anechoic chamber that can be used for EMI measurement. Referring to FIG. 2, when used as a completely anechoic chamber, the radio wave absorber 2A on the floor is placed on the floor. When used for EMI measurement, it has a radio wave absorber of 2A. Move the radio wave absorber 2B, which is placed separately on the rail, to an empty place and absorb the radio waves. The floor of the shield room 1 where the housing 2B was located is exposed and used as a ground plane. in the attic corresponding to a predetermined location on the exposed floor (i.e. ground plane). As in the case of Fig. 1, a small shield chamber 5 is provided, a base 6 is fixed, and a pole 7 is placed on the ceiling. through the opening and lower it vertically. The lower end surface of pole 7 is in contact with the upper end of radio wave absorber 2B. No, it is the required height. The difference from the antenna lifting/lowering turning device in Figure 1 is that the drive unit 8 on the floor outside the shield room 1, and a bell from the slit in the side wall of the small shield room 5. 11 and extended it to the drive section 8. The maintenance and inspection of the drive unit 8 is extremely thorough. It can be done easily.

[0015] Here, to explain another example of the structure of the floor of the shield room, as shown in Figure 1. In the anechoic chamber, the floor of the anechoic chamber has the configuration shown in FIG. 3, for example. Figure 3 Referring to Fig. 3, a fully anechoic chamber with a shared type that does not move the radio wave absorber on the floor is shown. The floor structure has been converted to EMI measurement. All over the floor of shield room 1 A tile-shaped ferrite absorber 12 is installed. It is removable on top of the absorber 12. The ground plane material 13 is spread all over. In the case of Figure 3, the ground plane material Reference numeral 13 denotes a connecting member 1 such as conductive rubber that fits between the metal plate 14 and the stepped portion on the bottom periphery of the metal plate 14. Consists of 5. Therefore, the ground plane material 13 is connected to the antenna lifting/lowering turning device. Since it can be laid on the floor or peeled off from the floor, conversion work can be carried out efficiently. Ru. Note that a metal film is attached as the ground plane material 13, and it cannot be spread over the entire floor. A resin film that can be used may also be used.

[0016]

[Effect of the idea]

As explained above, in the present invention, an antenna lifting/lowering turning device is provided on the ceiling. Therefore, there is no need to create a recess in the floor for storing the base, and construction costs can be reduced. Furthermore, since there are fewer things occupying the floor, it is easier for people to come and go and to move things around. Ma In addition, in the case of a completely anechoic chamber that can be shared for EMI measurement, the efficiency of conversion work will be improved. In addition, maintenance and inspection of the drive unit of the antenna lifting/lowering device can be carried out outside the dark room. This has the effect of making it possible to use the darkroom more efficiently.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing a main part of an embodiment of an anechoic chamber according to the present invention.

FIG. 2 is a longitudinal sectional view showing another embodiment of the anechoic chamber according to the present invention.

FIG. 3 is an enlarged sectional view of a main part showing another example of the floor structure in the anechoic chamber shown in FIG. 1;

[Explanation of symbols]

1 Shield room 2, 2A, 2B Radio wave absorber 3 Turntable 4 Test equipment 5 Small shield room 6 Base 7 Paul 8 Drive section 9 Antenna unit 10 Antenna 11 Belt 12 Ferrite absorber 13 Ground plane material 14 Metal plate 15 Connecting material

──────────────────────────────────────────────── ─── Continuation of front page (72) Creator Teiichi Miura 398 Shimoguchi, Takatsu-ku, Kawasaki City, Kanagawa Prefecture Tokin Shikisha (72) Creator Yoshiro Sato 398 Shimoguchi, Takatsu-ku, Kawasaki City, Kanagawa Prefecture Tokin Shikisha

Claims (3)

[Scope of utility model registration request] Claim 1: having a shield chamber, a base disposed in the ceiling of the shield chamber, one end of which is fixed to the base,
A vertically rotating antenna comprising: a pole that hangs down within the shield chamber and has the other end located at a predetermined height from the floor of the shield chamber; and an antenna unit that is attached to the pole so as to be movable up and down and rotatably attached. An anechoic chamber characterized by being equipped with a device. 2. The anechoic chamber according to claim 1, wherein the antenna lifting/lowering/rotating device is provided with a driving section for lifting/lowering and rotating the antenna unit, and the driving section is attached to the base. An anechoic chamber characterized by: 3. The anechoic chamber according to claim 1, wherein the antenna lifting/lowering/rotating device is provided with a driving section for lifting/lowering and rotating the antenna unit, and the driving section is disposed outside the shield room. An anechoic chamber characterized by