JP2554394Y2 - Anechoic chamber - Google Patents

Description

[Detailed description of the invention]

[0001]

The present invention relates to an anechoic chamber.
The present invention relates to an installation structure of an antenna elevating and turning device arranged in an anechoic chamber.

[0002]

2. Description of the Related Art It is known that an anechoic chamber used for an interference wave measurement test of electronic equipment has a structure in which a floor structure of a shielded room is a ground plane and a radio wave absorber is installed on a wall surface other than the floor. Such an anechoic chamber has almost the same radio wave propagation characteristics as an open site, and is called an EMI measurement anechoic chamber. On the other hand, when evaluating the characteristics of the antenna, a so-called perfect anechoic chamber is used in which a radio wave absorber is installed on the entire wall surface including the floor of the shielded room and has radio wave propagation characteristics almost equivalent to those in free space. .

In the EMI measurement, a test device and an antenna are placed on a ground plane in a dark room at a predetermined distance (3 m or 10 m).
And continuously change the height of the antenna from 1 m to 4 m. Then, the antenna receives the combined wave of the direct wave of the interference wave and the reflected wave from the ground plane, stops the movement of the antenna at the position where the noise level is maximized, and then moves the turntable on which the EUT is mounted. Rotate, stop the turntable in the direction that maximizes the noise level, and measure the noise level in the required frequency band. At this time, the antenna takes two types of data when the antenna is horizontal and when the antenna is vertical (horizontal and vertical polarization).

By the way, when performing EMI measurement, a base and
An antenna elevating and rotating device (hereinafter simply referred to as an apparatus) composed of an FRP pole standing on a base is used, and the antenna is fixed to a vertically movable antenna unit provided on the pole. The antenna unit is moved up and down via a belt by a driving unit including a motor and a driving pulley installed on a base. The drive unit also turns the antenna via the belt. The device weighs about 50 kg, and may be a movable type by attaching a caster to a base.

In the EMI measurement anechoic chamber, when there is a large amount of radio wave reflection from the drive unit installed on the base of the apparatus, or when it is desired to avoid the presence of the base itself, the floor of the shield room is dug down and surrounded by a shield material. Dent (for example, 1.2m square,
(A depth of about 0.5 m), the base is housed in a recess, and a floor structure is used in which only the poles of the device project from the ground plane.

In the case of a complete anechoic chamber shared with EMI measurement, E
When performing the MI measurement, the radio wave absorber of the wedge-shaped foam material installed on the floor of the shield room is moved inside the room to expose a part of the floor of the shield room as a ground plane. And
Each time the floor is converted, the equipment is loaded and unloaded. When converting a complete anechoic chamber with a tile-type ferrite absorber on the floor of a shielded room for EMI measurement and converting to the original anechoic chamber, a device placed on the floor (base installed with a radio wave absorber) Devices that are placed on the floor, such as
The ground plane member (metal plate) is spread or removed on the ferrite absorber by moving sequentially.

[0007]

As described above, in the anechoic chamber where the antenna elevating and lowering device is arranged on the floor, if the floor is provided with a recess for accommodating the base, the ground may be dug down,
Because the foundation must be sufficiently high, there is a problem that construction costs are high. On the other hand, in an anechoic chamber shared by EMI, the base is several times the cross-sectional area of the pole (1
(about m square), there is a problem that a person gets in the way when going in and out of the room, and there is a problem that there are many occasions such as moving into and out of the dark room such as entering and exiting the device, and handling is troublesome. . Further, when performing maintenance and inspection, it is necessary for an operator to enter a dark room or to select a device. SUMMARY OF THE INVENTION An object of the present invention is to provide an anechoic chamber with low construction cost and easy handling.

[0008]

According to the present invention, the antenna elevating and turning device is installed on the ceiling of the anechoic chamber. The base of the antenna elevating and turning device is installed behind the ceiling of the shield room, and the FRP pole erected on the base is hung down through the opening of the shield material on the ceiling. In addition, keep the lower end of the pole away from the floor.

[0009]

[Function] In the present invention, the base of the antenna elevating and rotating device is arranged behind the ceiling of the shielded room, and the pole is suspended from the base into the shielded room, so that various operations in the anechoic chamber can be efficiently performed. Can be.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments. Referring to FIG. 1, the illustrated anechoic chamber is an EMI in which a wedge-shaped radio wave absorber 2 is installed on five surfaces of the shield room 1 other than the floor (in the figure, both vertical walls and three ceilings are shown). It is a measurement anechoic chamber. The floor of the shield room 1 is a ground plane, on which a turntable 3 on which a test device 4 is mounted and which rotates is arranged. The turntable 3 has a built-in drive. A rectangular opening is formed in the ceiling corresponding to a position separated by a predetermined distance (3 m or 10 m) from the arrangement position of the turntable 3, penetrating the ceiling surface and the radio wave absorber 2. A small shield room 5 is provided behind the ceiling.

The antenna elevating and lowering device includes a base 6, which is fixed to the inner upper surface (ceiling surface) of the small shield room 5. A pole 7 extending downward is erected on the base 6, and a drive unit 8 including a drive pulley, an electric motor, and the like is arranged on the base 6. The pole 7 is a rectangular tube made of FRP, extends vertically through the opening, and reaches the inside of the shield chamber 1. The size of the opening is, for example, 100 mm
It is about × 100 mm, and there is almost no fear that the shield between the shield room 1 and the small shield room 5 becomes a problem.
If it is necessary to ensure the shield at the opening for the pole 7 because the small shield chamber 5 has slits (for example, for belt insertion or wiring insertion),
A shield member having a rectangular tray-like shape and a belt insertion slit formed on the inner bottom may be provided inside the pole 7 corresponding to the opening (that is, at a position corresponding to the opening). Also,
A belt insertion slit may be provided on the ceiling of the shield room 1 to fix the pole 7 directly to the ceiling of the shield room 1.

The length of the pole 7 is such that the antenna unit 9 fitted to the pole 7 is 1 m to 4 m from the floor of the shield room 1.
Is set to a size that can be moved up and down by the driving unit 8 via the belt inside the pole 7. The antenna 10 attached to the antenna unit 9 is turned by the driving unit and adjusted so as to receive a horizontally polarized wave or a vertically polarized wave.

As described above, the antenna elevating and turning device includes
Since it is not placed on the ground plane, a person can freely move in and out of the anechoic chamber as compared with the related art, and the test equipment 4 can be easily carried in and out. Anechoic chambers can be used indoors,
Even if it is outdoors, since the ceiling is made sturdy and the work space is secured behind the ceiling to install the radio wave absorber 2 on the ceiling, maintenance and inspection of the drive unit 8 in the small shield room 5 can be easily performed. .

FIG. 2 shows another embodiment of a complete anechoic chamber that can be used for EMI measurement. Referring to FIG. 2, when used as a complete anechoic chamber, a radio wave absorber 2A on the floor
Is placed on the floor. When used for EMI measurement, the radio wave absorber 2A is lifted, and the radio wave absorber 2B placed on another rail is moved to a vacant place, and the floor of the shield room 1 where the radio wave absorber 2B was located is located. Is exposed to form a ground plane. As in the case of FIG. 1, a small shielded room 5 is provided in the back of the ceiling corresponding to a predetermined position of the exposed floor (that is, the ground plane) to fix the base 6, and the pole 7 is passed through the opening of the ceiling. And lower it vertically. The lower end surface of the pole 7 has a required height that does not contact the upper end of the radio wave absorber 2B. The difference from the antenna elevating and slewing device of FIG.
The driving unit 8 is installed on the floor outside the shielded room 1, and the belt 11 is pulled out from the slit in the side wall of the small shielded room 5 and extended to the driving unit 8. Maintenance and inspection of the drive unit 8 can be extremely easily performed.

Here, another example of the floor structure of the shielded room will be described. In the anechoic chamber shown in FIG.
The floor of the anechoic chamber has, for example, the configuration shown in FIG.
Referring to FIG. 3, FIG. 3 shows a floor structure of a common type complete anechoic chamber in which the radio wave absorber on the floor is not moved, and is in a state converted for EMI measurement. A tile-shaped ferrite absorber 12 is provided on the entire floor of the shield room 1. A removable ground plane material 13 is spread over the absorber 12. In the case of FIG. 3, the ground plane material 13 is
It is made of a metal plate 14 and a connecting member 15 such as conductive rubber that fits into a step on the peripheral edge of the bottom surface. Therefore, since the ground plane material 13 can be laid on the floor or peeled off from the floor regardless of the antenna elevating / lowering device, the conversion work can be executed efficiently. As the ground plane material 13, a resin film to which a metal film is attached and which can be laid on the entire floor may be used.

[0016]

As described above, according to the present invention, since the antenna elevating and lowering device is provided on the ceiling, there is no need to provide a recess for accommodating the base on the floor, and the construction cost can be reduced. Furthermore, since there are few things occupying the floor, it is easy for people to come and go and to move things. Further, in the case of a complete anechoic chamber that can be used for EMI measurement, the efficiency of conversion work is improved.
In addition, the maintenance and inspection of the drive unit of the antenna
Since it can be performed outside the dark room, there is an effect that the dark room can be used efficiently.

[Brief description of the drawings]

FIG. 1 is a longitudinal 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.

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

[Explanation of symbols]

 Reference Signs List 1 shield room 2, 2A, 2B radio wave absorber 3 turntable 4 EUT 5 small shield room 6 base 7 pole 8 drive unit 9 antenna unit 10 antenna 11 belt 12 ferrite absorber 13 ground plane material 14 metal plate 15 connection Lumber

Continuing on the front page (72) Inventor Teiichi Miura 398 Komokuchi, Takatsu-ku, Kawasaki-shi, Kanagawa Prefecture Tokin Co., Ltd. Kaihei 3-124,099 (JP, A) Real opening, Sho 55-146595 (JP, U)

Claims (3)

(57) [Scope of request for utility model registration] 1. A base having a shield room, the base being disposed behind a ceiling of the shield room, and one end fixed to the base,
An antenna elevating and lowering swivel having a pole suspended in the shield chamber and having the other end positioned at a predetermined height from the floor of the shield chamber, and an antenna unit rotatably mounted on the pole and rotatably mounted on the pole An anechoic chamber characterized by having a device. 2. The anechoic chamber according to claim 1, wherein the antenna elevating and lowering device is provided with a driving unit for raising and lowering and rotating the antenna unit, and the driving unit is attached to the base. Anechoic chamber characterized by being used. 3. The anechoic chamber according to claim 1, wherein the antenna elevating and lowering device is provided with a driving unit for raising and lowering and rotating the antenna unit, and the driving unit is disposed outside the shield chamber. Anechoic chamber characterized by being