JP2968186B2 - Radio wave absorption wall - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio wave absorbing wall, and more particularly, to a radio wave absorbing wall effective for a countermeasure against a radio wave reflection failure of a television.

[0002]

2. Description of the Related Art Approximately twenty years have passed since the reflection of television radio waves by buildings became a social problem. At present, there are two methods of countermeasures against a TV radio wave reflection obstruction caused by a building wall: (1) a radio wave absorbing wall using a ferrite radio wave absorbing material, and (2) a building shape method using irregular reflection of a radio wave on the wall surface.

(1) The radio wave absorption wall is shown in FIGS.
As shown in FIG. 1, a ferrite tile (radio wave absorber) 22 is inserted between a precast concrete curtain wall 21 and a surface finishing material 24 thereof. Radio waves transmitted through the surface finishing material 24 are absorbed by the ferrite tile 22 and do not generate reflected waves. 23 in the figure is a reinforcing bar (radio wave reflector)
And 25 is a window glass.

[0004] The ferrite radio wave absorbing wall has a remarkable effect of prevention, but is very expensive, and cannot be used entirely in a rapidly increasing high-rise building.

[0005] Next, regarding the irregular reflection type wall of (2), when a radio wave is incident on a flat precast concrete curtain wall, a strong reflected wave in the form of a beam is generated as if the light is reflected by a mirror, and a reflection failure occurs. I do. However, as shown in FIG. 13, the wall surface is a curved surface 26 on the order of several meters,
As shown in FIG. 14, when a large number of ribs 27 each having a length of about 1 m are provided, a reflected wave in the form of a beam is not generated, and no reflection failure occurs.

[0006] The diffuse reflection type wall has a design limitation and cannot be applied to all buildings.

[0007] It has been known that television wave reflection interference on a building surface having many glass windows is small. This is because radio waves pass through the window glass and enter the room, and are irregularly reflected by fixtures such as desks in the room, so that reflected waves having the same phase are not generated.

In recent years, reinforced concrete curtain walls have been used for wall surfaces of buildings such as high-rise buildings,
Synthetic fiber reinforced concrete (FRC) curtain walls have been used.

Radio waves have electric and magnetic components, and propagate at the speed of light in vacuum and air. And for radio waves,
All materials act as conductors, dielectrics, magnetics, or composites of them, and their radio wave states are determined. here,
The conductor is metal, carbon, etc., the dielectric is concrete, air, glass, etc., and the magnetic substance is ferrite, etc.

Considering the reflection of television waves on the building wall, in the case of a reinforced concrete curtain wall, as shown in FIG. 15, television waves are reflected slightly on the surface, and the rest is covered with concrete 21 having a small dielectric constant.
Passes through the wire without much attenuation and reaches the reinforcing bar net 23. The reinforcing bar 23 is regarded as a conductor network having a mesh of several tens of mm, and has a wavelength of 1 mm.
TV waves of about 3 m cannot pass through, and are reflected almost completely here. The reflected wave passes through the concrete at the cover and goes out.

In the case of an FRC curtain wall, FIG.
As shown in (1), the radio wave is slightly reflected on the front surface of the FRC1, and the rest is not greatly attenuated and reaches the boundary surface on the back surface. The combination of the reflected waves at the two boundary surfaces becomes a reflected wave as a wall surface. The amount of this reflection depends on the dielectric constant of the material and the wall thickness.

The present applicant has filed a Japanese Patent Application No. Hei 6-310325.
In the issue, it can be provided relatively inexpensively,
We propose a radio wave transmission wall that can be implemented without any restrictions on design and is effective against TV radio wave reflection obstacles.

According to the proposal, a curtain wall used for the wall surface of a building is a synthetic fiber reinforced concrete (FRC) curtain wall, and a ferrite tile is provided at a portion facing a beam of a steel frame of the building. Alternatively, carbon fiber reinforced concrete (CFRC) is provided.

[0014]

Although the above proposal is effective, ferrite tiles have problems such as heavy weight, poor workability, lack of design freedom, and high cost. is there.

An object of the present invention is to provide an inexpensive radio wave absorbing wall which is lightweight, has good workability, and has a high degree of design freedom.

[0016]

[Knowledge] As a result of various studies, the inventor of the present invention has shown that, as shown in FIG. It has been found that placing a 377 ohm square resistive film R at a position results in a radio wave absorbing wall.

Λ / 4 of the distance between the reflector M and the resistive film R
Need not be completely λ / 4, but may be an approximate value. Also, the resistance 377 ohm square of the resistance film R does not need to be completely 377 ohm square. Further, the reflector M does not need to have an infinite plane area.

The distance L, the resistance value of the resistance film R, and the width of the reflection plate M have a mutual relationship, and the optimum value is obtained by experiments and the like. Further, the reflection plate M and the resistive film R
When a dielectric (for example, vinylon fiber reinforced concrete “VFRC”) is inserted between the two, the radio wave wavelength between them is reduced to 1 / (εr) ^1/2 (εr: dielectric constant of the dielectric), resulting in A radio wave absorbing wall having a small wall thickness can be obtained. The present invention has been made based on the above findings.

[0019]

According to the present invention, there is provided a curtain wall for use on a building wall, the curtain wall being a radio wave transmitting synthetic fiber reinforced concrete (FR).
C) A curtain wall is provided with a resistive film near a surface facing a reflector such as a beam of a steel frame of a building.

According to the present invention, there is provided a curtain wall used for a building wall, wherein the curtain wall is a radio wave transmitting type synthetic fiber reinforced concrete curtain wall, and the surface of the radio wave transmitting type synthetic fiber reinforced concrete is a surface. A reflector is provided on the back surface of the curtain wall, and a resistive film is provided at a quarter wavelength position in front of the reflector between the radio wave transmitting type synthetic fiber reinforced concrete and the surface finish. Have been.

Further, according to the present invention, the resistive film is characterized by being selected from a planar resistive film, a belt-like resistive film, a perforated resistive film, or a resistive network.

According to the invention, the reflector is a metal net or a carbon fiber net.

The term "near the surface" is preferably such that the distance from the beam or the reflector of the skeleton of the building is approximately ４ of the radio wave wavelength in consideration of the wavelength shortening effect of the curtain wall itself. .

Further, it is preferable that the resistance value of the resistance film is approximately 377 ohm square.

[0025]

In the radio wave absorbing wall configured as described above, as is known from the knowledge, the reflected wave from the beam or the like of the skeleton steel frame or the reflector is suitably absorbed by the resistive film.

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 2, the curtain wall denoted by reference numeral 1 is a radio wave transmitting synthetic fiber reinforced concrete (FR).
C) Vinylon fiber reinforced concrete (VFRC)
The surface 2 is covered with a surface finishing material 3 and reinforced with ribs 4 and 4 to form a window 5 at the center in the example shown. The resistive film 6 is provided between the concrete 2 facing the beam 10 of the steel frame of the curtain wall 1 and the fan coil duct 11 and the surface finishing material 3. Thus, the radio wave absorbing portion A and the radio wave transmitting portion B are defined in the curtain wall 1 by the presence or absence of the resistive film 6. Then, as shown in FIG. 3, the distance between the resistive film 6, the beam 10, and the fan coil duct 11 is L1 and L2. Here, since the target television wave is 90 MHz for one channel to 220 MHz for 12 channels, λ / 4 is about 83 to 34 cm.

Here, in the curtain wall 1 in the case where the fan coil duct 11 is used as a reflector, the thickness D of the curtain wall 1 shown in FIG. 3 is about 70 mm and the dielectric constant εr is 4 to 5. Therefore, considering the wavelength shortening effect of the curtain wall 1, the distances L1 and L2 between the resistive film 6 and the beams 10, the fan coil ducts 11 and the like are 83 to 34 cm of the above-described size. Effective radio wave absorption wall is obtained.

FIG. 4 shows a second embodiment of the present invention. This curtain wall 1A is an example in which a belt-shaped resistance film 6A is used as a resistance film, and the other parts are configured in the same manner as in FIG. In this embodiment, the same operation and effect as in FIG. 2 can be obtained, and the workability can be improved. The longitudinal direction of the resistive film 6A is aligned with the direction of the electric field of the television wave. That is, since the normal television wave is a horizontally polarized wave, the longitudinal direction of the resistive film 6A is horizontal.

FIG. 5 shows a third embodiment of the present invention. This curtain wall 1B is an example in which a perforated resistance film 6B is used as a resistance film and the other parts are configured in the same manner as in FIG. In this embodiment, the same operation and effects as those of FIG.
Thereby, the concrete 2 and the finishing material 3 are joined, and the adhesive strength can be improved.

FIG. 6 shows a fourth embodiment of the present invention. This curtain wall 1C uses a resistance network 6C as a resistance film.
The other is an example configured similarly to FIG. In this embodiment, the same operation and effect as in FIG. 2 can be obtained, and the workability can be improved. The mesh of the resistance network 6C is considerably smaller than the radio wave wavelength.

FIG. 7 shows a fifth embodiment of the present invention. In this curtain wall 1D, the surface of a vinylon fiber reinforced concrete (VFRC) 2 which is a radio wave transmission type synthetic fiber reinforced concrete (FRC) is a surface finishing material 3. It is covered and has a window 5 in the center. On the back surface of the curtain wall 1D, for example, a metal net 7 as a reflector is provided, and between the concrete 2 and the finishing material 3, a planar resistance film 6 is provided. This embodiment is used for a portion of the steel frame shown in FIG. 2 where the beam 10 and the fan coil duct 11 are not provided, and an effective radio wave absorbing wall as shown in the findings can be obtained. Note that a carbon fiber net can be used instead of the metal net 7.

FIG. 8 shows a sixth embodiment of the present invention. This curtain wall 1E uses a strip-shaped resistive film 6A, and the other parts are shown in FIG.
This is an example configured in the same manner as described above. This embodiment has substantially the same operation and effect as the second embodiment.

FIG. 9 shows a seventh embodiment of the present invention. This curtain wall 1F is an example in which a perforated resistance film 6B is used as a resistance film, and the other parts are configured in the same manner as in FIG. This embodiment has substantially the same operation and effect as the third embodiment.

FIG. 10 shows an eighth embodiment of the present invention. This curtain wall 1G is an example in which a resistive network 6C is used as a resistive film and the other parts are configured in the same manner as in FIG. This embodiment has substantially the same operation and effect as the fourth embodiment.

[0036]

Since the present invention is configured as described above, it has the following effects. (1) The reflected wave is absorbed by the resistive film, which is effective in preventing the reflection of television radio waves. (2) Since ferrite tiles are not used, weight reduction,
The workability can be improved, the design can be freely designed, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a side view illustrating the principle of the present invention.

FIG. 2 is a perspective view showing a first embodiment of the present invention.

FIG. 3 is a side sectional view illustrating an effect.

FIG. 4 is a perspective view illustrating a second embodiment of the present invention.

FIG. 5 is a perspective view illustrating a third embodiment of the present invention.

FIG. 6 is a perspective view illustrating a fourth embodiment of the present invention.

FIG. 7 is a perspective view illustrating a fifth embodiment of the present invention.

FIG. 8 is a perspective view illustrating a sixth embodiment of the present invention.

FIG. 9 is a perspective view illustrating a seventh embodiment of the present invention.

FIG. 10 is a perspective view illustrating an eighth embodiment of the present invention.

FIG. 11 is a perspective view showing a radio wave absorbing wall using a ferrite tile.

FIG. 12 is a detailed side sectional view of FIG. 11;

FIG. 13 is a side sectional view showing an example of a diffuse reflection type wall.

FIG. 14 is a side sectional view showing another example of the irregular reflection type wall.

FIG. 15 is an explanatory view showing a reflection state of radio waves on a reinforced concrete curtain wall.

FIG. 16 is an explanatory view showing reflection and transmission of radio waves in a synthetic fiber reinforced concrete curtain wall.

[Explanation of symbols]

 A: Radio wave absorbing portion B: Radio wave transmitting portion M: Metal plate R: Resistive film 1, 1A-1G: Curtain wall 2: Vinylon fiber reinforced concrete 3: Surface finish Material 4 Rib 5 Window 6 Planar resistance film 6A Band resistance film 6B Perforated resistance film 6C Resistance network 6b Hole 7 Metal Net 10 ・ ・ ・ Beam 11 ・ ・ ・ Fan coil duct 21 ・ ・ ・ Precast concrete curtain wall 22 ・ ・ ・ Ferrite tile 23 ・ ・ ・ Reinforcing bar 24 ・ ・ ・ Surface finishing material 25 ・ ・ ・ Window glass 26 ・ ・ ・ Curved surface 27 ・ ・ ・ Rib

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroaki Nakagawa 2-9-1-1, Tobita-Shi, Chofu-shi, Tokyo Kashima Construction Co., Ltd. (72) Inventor Shigeyuki Akihama 1-2-1, Moto-Akasaka, Minato-ku, Tokyo No. 7 Inside Kashima Construction Co., Ltd. (72) Inventor Yo Yo Ohya 1-9-11 Nihonbashi Horidomecho, Chuo-ku, Tokyo Inside Kureha Chemical Industry Co., Ltd. (56) References JP-A-1-223243 (JP, A) JP-A-4-163998 (JP, A) JP-A-58-210696 (JP, A) JP-A-3-32499 (JP, U) JP-A-3-48298 (JP, U) (58) Fields surveyed ( Int.Cl. ⁶ , DB name) E04B 2/88-2/96 E04B 1/92 E04C 2/52

Claims (4)

(57) [Claims] 1. A curtain wall used for a building wall, wherein the curtain wall is a radio wave transmitting type synthetic fiber reinforced concrete curtain wall, and a resistive film is provided near a surface of a steel frame of a building facing a reflector such as a beam. A radio wave absorption wall, characterized by having a wall. 2. A curtain wall used for a building wall, wherein the curtain wall is a radio wave transmitting type synthetic fiber reinforced concrete curtain wall, and a surface of the radio wave transmitting type synthetic fiber reinforced concrete is covered with a surface finishing material. A reflector is provided on the back surface of the curtain wall, and a resistive film is provided at a quarter wavelength position in front of the reflector between the radio wave transmitting type synthetic fiber reinforced concrete and the surface finishing material. Characteristic radio wave absorption wall. 3. The resistive film includes a planar resistive film, a belt-like resistive film,
3. The radio wave absorption wall according to claim 1, wherein the wall is selected from a perforated resistance film or a resistance net. 4. The radio wave absorbing wall according to claim 2, wherein the reflector is a metal net or a carbon fiber net.