JPH10246744A - Structure of radio wave anechoic chamber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently effect installation and withdrawing works of heavy goods by a method wherein a fright lifter is provided above a quiet zone and a heavy to-be-measured object is lifted. SOLUTION: In a radio anechoic chamber 1, a ceiling face, a wall face and a floor face are enclosed with a radio wave shield material 2, and also a radio wave absorber 3 is a provided. A freight lifter 6 is installed on a ceiling at a center part of a quiet zone 5 on a reception side. Above the quiet zone 5 is place where influences of scattered waves and reflected waves are least, and changes of radio wave dark room characteristics can be minimized in accordance with installation of the freight lifter 6. The freight filter 6 is generally a winch, and an operator makes remote control. A write is wound on the winch and a leading end of the wire has a hook made of a metal. The fright is pulled by this hook. Installation and withdrawal of heavy goods can be carried out shortly. When measuring in the radio anechoic chamber 1, the hook is sound to an upmost height of the ceiling so that influences are not exerted on the measurement.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an anechoic chamber used for measuring and evaluating antenna radiation directivity characteristics and electromagnetic environment compatibility.

[0002]

2. Description of the Related Art In an anechoic chamber, the influence of reflected waves generally decreases as the distance from a wall surface increases. A range in which the level of unnecessary waves such as scattered waves and reflected waves is equal to or less than a predetermined value (for example, -50 dB) is called a quiet zone. Usually, a measurement object, a test device, and the like are arranged in a quiet zone to perform measurement and evaluation. The quiet zone is often located between the floor and the ceiling, and in the example of the ceiling height of 5 meters, is at a height of 2 to 3 meters from the floor surface. Therefore, an object to be measured and a test device are placed in a quiet zone at a predetermined height (for example, 2 to 3 meters) from the floor using a table. A table on which an antenna or a transmitting device serving as a radio wave emission source is mounted is referred to as a transmitting table, and a table on which a measurement object or the like is mounted is referred to as a receiving table.

[0003] In some cases, a heavy measurement object, a test device, or the like is placed on a receiving stand to perform measurement and evaluation. For example, the measurement of the reception sensitivity of a pager (wireless call receiver) is performed by attaching a pager to be measured to a salty body that functions as a pseudo human body. The salty body is made of an acrylic resin cylindrical case having a diameter of 300 millimeters and a height of 1700 millimeters, in which physiological saline is put. Approximately 120 liters of physiological saline is contained in the salty body,
Salty bodies weigh more than 120 kilograms.
In order to perform reception sensitivity measurement, the salty body needs to be placed on the receiver.

Conventionally, a salty body containing physiological saline has been lifted by a large number of persons and placed on a receiving table. When the number of people is small, after the salty body is installed on the receiving stand with the interior empty, for example, a saline solution placed in a plastic tank of about 20 liters is carried, and the saline solution is injected into the salty body with a pump. The work was repeated several times.

[0005]

As described above, when a heavy object is placed on a measuring table such as a receiving table, the conventional anechoic chamber does not consider the anechoic chamber itself. Preparatory work and removal work require a lot of manpower, which takes time. The time required for a series of measurements and evaluations, including preparation and withdrawal work, becomes longer, and the efficiency of measurement and evaluation work decreases. Therefore, the anechoic chamber, which is a relatively special and expensive test facility, cannot be effectively operated.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to provide an anechoic chamber in which a heavy object can be installed in a quiet zone without requiring human labor and time.

[0007]

In order to solve the above-mentioned problems, an anechoic chamber according to the present invention is provided with a cargo elevating device above a quiet zone. Since a heavy measurement object or the like can be moved up and down by the cargo elevating device, the installation and withdrawal work of the heavy object can be performed efficiently.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic view showing the structure of an anechoic chamber according to the present invention. FIG. 1 shows an example in which a cargo lifting device is installed on the ceiling at the center of the quiet zone on the receiving side.

The anechoic chamber 1 is constructed by surrounding a ceiling surface, a wall surface and a floor surface with a radio wave shielding material 2 and providing a radio wave absorber 3 on the ceiling surface and the wall surface. The anechoic chamber 1 has a structure in which a radio wave absorber 3 is also laid on the floor surface so that there is no reflection from the pseudo ground. Reference numeral 4 denotes a transmitting-side quiet zone, and reference numeral 5 denotes a receiving-side quiet zone.

A cargo lifting device 6 is installed on the ceiling at the center of the quiet zone 5 on the receiving side. The cargo elevating device 6 is a very common winch that can be remotely operated by an operator. The winch used here has a wire wound around it, and the tip of the wire has a metal hook. Cargo can be towed by this hook. Further, when the measurement is performed in the anechoic chamber 1, the hook is wound up to the top of the ceiling so as not to affect the measurement.

[0011] Immediately above the quiet zone is a place where the influence of scattered waves and reflected waves is minimal. Therefore, by installing the freight lifting device 6 directly above the quiet zone, it is possible to minimize the change in the anechoic chamber characteristics of the anechoic chamber 1 caused by installing the freight lifting device 6.

The transmitting table 7 and the receiving table 8 are each movable. The transmitting table 7 and the receiving table 8 have stairs. The height of the transmitting table 7 and the receiving table 8 is about 3 meters. The upper part of the receiver 7 and the transmitter 8 is 1
It is a square with sides of about 1.2 meters. Radio wave absorbers are attached to the side surfaces of the receiving table 7 and the transmitting table 8.

FIG. 2 is an explanatory view showing a work procedure for placing a heavy object to be measured on the receiving table using the cargo lifting device.
FIG. 2 shows an example in which a salty body is placed as a heavy measurement object. First, as shown in FIG. 2A, the position of the receiving stand 8 is set to a position B which is displaced from the position of the quiet zone on the receiving side to such an extent that it can be lifted and lowered.
The point A just below the cargo lifting device 6 corresponds to the center of the quiet zone on the receiving side.

Next, as shown in FIG. 2 (b), the salty body is moved to the point A, and the operator lowers the wire 6W of the cargo lifting device 6 by remote control or the like. Furthermore, the wire 9W attached to the salty body 9 is hung on the metal hook 6F attached to the tip of the wire 6W.

Next, as shown in FIG. 2 (c), the salty body 9 is pulled up by the cargo elevating device 6 until the receiving stand 8 can return to the point A. Thereafter, the receiving stand 8 is returned to the point A.

Finally, as shown in FIG. 2D, the salty body 9 is lowered on the receiving stand 8. Salty body 9
The wire 9W attached to the hook 6 of the cargo lifting device 6
After removing from F, the wire 6W of the cargo lifting device 6 is wound up.

As described above, the salty body 9 can be easily installed in the quiet zone 5 above the receiving stand 8. By performing the series of operations described above in reverse order, the salty body 9 can be easily lowered from the receiving stand 8.

Although FIG. 2 shows an example in which the salty body 9 is installed, a heavy measuring device such as an antenna positioner can be installed on the receiving stand 8 in a similar manner.

The cargo lifting device 6 may be provided above the transmitting side quiet zone 4. Further, the cargo lifting / lowering device 6 may be provided above the transmitting side quiet zone 4 and above the receiving side quiet zone 5 respectively.

[0020]

As described above, the anechoic chamber according to the present invention is provided with a cargo lifting device above the quiet zone, so that a heavy measurement object or the like can be installed in the quiet zone without requiring much labor and time. be able to. Since a heavy object can be installed and withdrawn in a short time, measurement and evaluation can be performed efficiently, and more measurement and evaluation can be performed within a limited time. Since the cargo elevating device is installed above the quiet zone, changes in the anechoic chamber characteristics due to the installation of the cargo elevating device can be minimized.

[Brief description of the drawings]

FIG. 1 is a schematic view showing the structure of an anechoic chamber according to the present invention.

FIG. 2 is an explanatory diagram showing an operation procedure for placing a heavy measurement object on a receiving table using the cargo lifting device.

[Explanation of symbols]

 1 Anechoic Chamber 4,5 Quiet Zone 6 Cargo Lift 7 Transmitter 8 Receiver

Claims (1)

[Claims] 1. A structure of an anechoic chamber, wherein a cargo lifting device is installed above a quiet zone in the anechoic chamber.