JP2983908B2 - Thin radio wave absorbing 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 used for an outer wall of a building as a countermeasure for preventing a radio wave reflection obstruction of a building such as a television ghost obstacle, and more particularly, to reducing the thickness thereof.
The present invention relates to a thin electromagnetic wave absorbing wall with reduced weight.

[0002]

2. Description of the Related Art The basic structure of this kind of radio wave absorbing wall using a ferrite plate (ferrite tile) is disclosed in Japanese Patent Publication No. 55-4 / 1979.
No. 9798, in which a plurality of ferrite plates are continuously coupled in the direction of the magnetic field of the arriving radio wave, and provided with a gap (at intervals) in the direction of the electric field. It has a structure in which the back surface is lined with a metal plate or metal mesh serving as a radio wave reflector.

[0003] In the case of a radio wave absorbing wall having the above structure, a surface finishing material such as an exterior tile is attached to the surface of the ferrite plate using a gap in the direction of an electric field as a practical measure to prevent the ferrite plate from falling. , Concrete is cast on the back side of them with the reflection muscle (reflection mesh),
A precast curtain wall structure in which concrete is filled between the ferrite plates and the back surface of the ferrite plates is used.

FIG. 10 shows a conventional concrete-integrated radio wave absorbing wall having a structure in which a ferrite tile 1 is fixed with an exterior tile with special feet (porcelain tile or the like) 2 as a measure for preventing the ferrite tile 1 from falling. In this case, a ferrite tile 1 is arranged in front of a reinforcing bar 3 forming a metal reflection mesh (radio wave reflector) so as to be continuous in the magnetic field direction of incoming radio waves and discontinuous in the direction of an electric field, and to provide an exterior tile 2 with a special foot. Ferrite tile 1
And a concrete 4 is placed on the rear side of the front wall of the precast curtain wall structure of the ferrite and the concrete to form a radio wave absorbing wall. The radio wave absorbing wall shown in FIG. 10 is now widely used as a measure against television ghost on the outer wall of a building.

[0005] Such a radio wave absorbing wall using a ferrite tile has excellent radio wave absorbing properties and has problems in weight and cost. However, at present, there is no substitute for a radio wave reflection preventing wall material of a building.

[0006] On the other hand, high-rise buildings are required to reduce the weight of their constituent members. Recently, low-cost materials, especially lightweight and excellent in earthquake resistance, have been required for building materials of high-rise buildings. . In order to solve the problem of such building materials, new building materials such as fiber reinforced concrete mixed with carbon fiber and the like have been studied and some of them have been put into practical use.

[0007] Such a technical trend is naturally required for a radio wave absorbing wall, and a light and thin electromagnetic wave absorbing wall is being developed. A typical example thereof is an integrated radio wave absorbing wall structure with carbon fiber reinforced concrete shown in FIG. 11 (Japanese Utility Model Publication No. 6-48951).

The carbon fiber reinforced concrete integrated radio wave absorbing wall shown in FIG. 11 has a ferrite tile 1 disposed so as to be continuous in the direction of a magnetic field and discontinuous in the direction of an electric field. A plastic fiber reinforced concrete (reinforced concrete in which non-conductive fibers are mixed into concrete; hereinafter, referred to as VFRC) 6 is cast in the gap between the ferrite tiles 1 and between the ferrite tiles 1. A metal reflection mesh 7 is arranged behind the ferrite tile 1 and carbon fiber reinforced concrete (reinforced concrete in which carbon fiber is mixed into concrete; hereinafter referred to as CFRC)
8). In addition, a shear connector (in this case, a stainless steel metal rod or the like) 9 for securing the bonding strength between the VFRC 6 and the CFRC 8 is integrated with the metal reflection bar 7, thereby reinforcing the combination of the VFRC 6 and the CFRC 8. doing. Where VFR
The reason why the combined structure of C6 and CFRC8 is
If FRC is used, the electric wave absorption characteristics are significantly deteriorated due to the electrically large effective permittivity of CFRC. To avoid this, conductive material is provided on the front side, which is the radio wave arrival side, and in the gap between the ferrite tiles 1. VFRC reinforced concrete with non-conductive plastic fiber is provided.

In the actual manufacture of the radio wave absorbing wall shown in FIGS. 10 and 11, in order to keep the ferrite tile 1 continuous in the direction of the magnetic field, a glass fiber reinforced plastic (hereinafter referred to as FRP) as shown in FIG. Conventionally, a ferrite pressing plate 10 made of a concrete molded plate or the like is fixed to the back surface of the ferrite tile 1 with an adhesive or the like (Japanese Patent Application Laid-Open No. 64-10849). However, the ferrite holding plate 10 is a simple long plate.

[0010]

As mentioned above, the requirements for building materials for high-rise buildings are recently low-cost materials that are particularly lightweight and have excellent seismic resistance. Although a lightweight and thin structure is required in accordance with the technological trend, the conventional concrete-integrated structural idea shown in FIGS. Has not been obtained yet.

[0011] In the present invention, it is difficult to reduce the weight and thickness of the electromagnetic wave absorbing material, ferrite as a radio wave absorber. Reduce the amount of concrete that is
The idea is to change the idea of the curtain wall structure to solve the problem. Therefore, (1) Instead of casting concrete behind and behind the ferrite plate (ferrite tile), which is a radio wave absorbing material, replace it with a structure that can be fixed with concrete with a reinforcing rib structure that also serves as reinforcement of the concrete itself. Is it not possible to obtain (2) Simultaneously with a ferrite plate that requires only the minimum amount of concrete required for concrete reinforcement? (3) To make concrete reinforcement as thin and efficient as possible We examined whether a lattice-like rib structure generally used for reinforcement could not be used, or (4) finally, a structure that could use conventional fiber-reinforced concrete to secure the strength of the concrete itself.

The present invention realizes a structure taking the above points into consideration, thereby reducing the weight and weight of the radio wave absorbing wall.
It is an object of the present invention to provide a thin radio wave absorbing wall which can be suitably used as an outer wall material such as a wall surface, a column, a beam, etc. of a high-rise building by solving a reduction in thickness.

Other objects and novel features of the present invention will be clarified in embodiments described later.

[0014]

In order to achieve the above object, a thin radio wave absorbing wall according to the present invention comprises a thin ferrite unit having a ferrite tile fixed to a ferrite pressing plate in the direction of an electric field by continuously connecting the ferrite tile to a ferrite pressing plate in the direction of an electric field. Having a structure arranged at intervals, the ferrite holding plate is made of insulating lightweight foam, and the ferrite holding plate is provided with grooves along the direction of the electric field for arranging the reinforcing ribs in the direction of the magnetic field. It is characterized by being formed repeatedly.

Further, in the thin radio wave absorbing wall, a fiber reinforced concrete as a reinforcing rib material may be provided between the ferrite units and in the concave groove so as to be fixedly integrated.

Further, the ferrite holding plate may have a hollow portion, and a lightweight member having a specific gravity of 1.0 or less may be inserted into the hollow portion.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the thin radio wave absorbing wall according to the present invention will be described below with reference to the drawings.

A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional plan view of a thin radio wave absorbing wall constituting a straight radio wave absorbing wall with an exterior tile,
FIG. 2 is a side view of the same, and FIG. 3 is a rear view of the thin radio wave absorbing wall from which the reflection plate is omitted. It has a structure arranged at intervals in the direction. Reference numeral 30 denotes an exterior tile with a shear connector which is placed on the front side of the ferrite tile 1 in the direction of arrival of radio waves, 40 denotes a fiber-reinforced concrete that has been poured (poured or sprayed) between the ferrite units 20, and 50 denotes a fiber-reinforced concrete It is a metal reflector such as stainless steel fixed to the back side of concrete.

First, the structure of the ferrite holding plate 15 which is the most characteristic in this embodiment will be described.
In this embodiment, in order to solve the above-mentioned problem of the radio wave absorbing wall, the idea is changed, and instead of the ferrite holding plate 10 made of a simple long plate such as FRP or concrete molding plate as shown in FIG. 4, a long block-shaped ferrite holding plate 15 made of an insulating lightweight foamed organic material, preferably a closed cell structure such as styrene foam, or an insulating lightweight foamed inorganic material such as a fiber-mixed foamed lightweight concrete. And the ferrite holding plate 1
In FIG. 5, concave grooves 16 along the electric field direction of the incoming radio wave for arranging the reinforcing rib material are repeatedly formed at intervals in the magnetic field direction.

As shown in FIG. 5, the ferrite unit 2
0 denotes a ferrite holding plate 15 having a concave groove 16 shown in FIG.
The ferrite tiles 1 are continuously joined together and fixed by an adhesive or the like. The longitudinal direction of the ferrite pressing plate 15 where the ferrite tiles 1 are continuous is the magnetic field direction of the arriving radio wave. Here, both sides of the ferrite tile 1 are tapered so that the front side, which is the direction in which radio waves arrive, is slightly narrower than the back side. On the other hand, the ferrite holding plate 15
Are tapered on both sides so that the width of the back surface is slightly smaller than the front surface of the ferrite tile 1 mounting surface, and the concave grooves 16 are arranged at equal intervals on the back surface side.

The ferrite units 20 of FIG. 5 are arranged with a gap in the direction of the electric field designed in advance as shown in FIG. At this time, it is desirable that the concave grooves 16 on the back surface of each ferrite unit 20 be aligned substantially parallel to the electric field direction.

In the case of forming a plain radio wave absorbing wall with an exterior tile, an exterior tile 30 with a shear connector is placed on the front side of the ferrite unit 20 as shown by phantom lines in FIGS. A fiber reinforced concrete 40 mixed with a non-conductive reinforcing fiber such as glass fiber is poured (poured or sprayed) between the ferrite units 20, and the ferrite unit 20, the exterior tile 30 with the shear connector and the fiber reinforced concrete 40 are formed. And a metal reflector 5 such as stainless steel as a radio wave reflector behind the fiber reinforced concrete 40.
0 was provided and integrated with an adhesive. As a result, a thin radio wave absorbing wall having a precast concrete structure is obtained. At this time, as can be seen from FIG. 3, the fiber reinforced concretes 40 provided in the gaps between the adjacent ferrite units 20 serve as the reinforcing ribs along the magnetic field direction, and the fiber reinforced concretes respectively entered into the concave grooves 16 on the back surface of the ferrite unit 20. Since the concrete 40 serves as reinforcing ribs along the direction of the electric field, the fiber reinforced concrete 40
Constitute a grid-like reinforcing rib, and have sufficient strength as a structural material with a minimum amount of concrete.

The shear connector 31 integrated with the exterior tile 30 is buried in the cast fiber-reinforced concrete 40, so that the fixing strength of the exterior tile 30 to the fiber-reinforced concrete 40 is sufficiently ensured. .
In addition, a joint material (a caulking material or the like) 32 is provided in a gap between the adjacent exterior tiles 30 for waterproofing.

In this embodiment, the thickness of the ferrite tile 1 is 8 mm, the width A in the electric field direction is 100 mm,
The gap B between the adjacent ferrite tiles 1 was 70 mm, and the porosity of the ferrite was set to about 40%. Further, the thickness of the ferrite pressing plate 15 is 40 mm, the groove width C of the concave groove 16 is set to be approximately the same as or slightly larger than the gap B, and the distance D between the adjacent concave grooves 16 in the magnetic field direction is equal to the gap B. It is desirable to set it to the same level or more. Here, the groove width C of the concave groove 16 was 70 mm, the interval D was 100 mm, and the depth was 30 mm. The thickness of the exterior tile 30 was 12 mm.

According to the first embodiment, the following effects can be obtained.

(1) The ferrite tile 1 is fixed to the ferrite pressing plate 15 made of an insulating lightweight foam so as to be continuous in the magnetic field direction of the arriving radio wave to form a ferrite unit 20.
The ferrite units 20 are arranged at intervals in the direction of the electric field, and the fiber reinforced concrete 40 is provided in the gap between the adjacent ferrite units 20 and in the groove 16 formed along the direction of the electric field on the back of the ferrite holding plate 15. Thus, the reinforcing ribs in the form of a lattice as shown in FIG. 3 can be constituted by the fiber reinforced concrete 40, and sufficient strength can be secured as a structural material with a minimum amount of concrete.

(2) Since the ferrite holding plate 15 is an insulating lightweight foam and the fiber reinforced concrete 40 is not driven behind the ferrite unit 20 except in the concave groove 16 of the ferrite unit 20, a required amount of driving is required. This is the minimum, and it is possible to reduce the weight and the thickness.

(3) The ferrite tile 1 is tapered on both sides so that the front side, which is the direction of arrival of radio waves, is slightly narrower than the back side, and the ferrite pressing plate 15 is smaller than the front side where the ferrite tile 1 is mounted. Both sides are tapered so that the width of the back surface is slightly narrowed. Therefore, when the lattice-shaped reinforcing ribs are formed by the fiber-reinforced concrete 40, the lattice-shaped fiber-reinforced concrete 40 does not fall back and forth. It will be securely held.
Therefore, a problem such as dropping of the ferrite tile 1 does not occur.

(4) As described above, since the reinforcing ribs in the form of a lattice can be made of the fiber reinforced concrete 40, no reinforcing steel bars or the like are required, and in this respect, the weight can be reduced and the structure can be simplified. .

(5) Since it can be configured to be lightweight and thin, it can be easily used not only as a wall surface of a high-rise building but also as an outer wall material such as a pillar or a beam for preventing radio wave reflection.

FIG. 7 shows a structure of a thin radio wave absorbing wall suitable for using CFRC according to a second embodiment of the present invention. In this case, the structure and arrangement of the ferrite unit 20 are the same as those of the first embodiment, but the use of the exterior tiles 35 with feet in the center of the back surface is used.
The difference is that the FRC 45 is cast in the gap in the electric field direction of the ferrite unit 20 and in the concave groove formed in the ferrite holding plate 15. Since the foot 36 at the center of the rear surface of the exterior tile 35 with feet enters the gap in the direction of the electric field between the adjacent ferrite tiles 1, the dielectric constant of the gap in the direction of the electric field can be controlled. The effective permittivity can be suppressed to a sufficiently low value by reducing the amount of the high permittivity CFRC entering the gap in the direction. Note that members that are the same as or correspond to those in the first embodiment are given the same reference numerals, and descriptions thereof are omitted.

According to the second embodiment, there is an advantage that the ferrite unit 20, the armored tile 35 and the CFRC 45 can be fixedly integrated by driving a CFRC having excellent strength as a structural material. . Other functions and effects are the same as those of the first embodiment.

FIG. 8 shows a third embodiment of the present invention, which shows a structure of a thin radio wave absorbing wall having reinforcing bars such as a reinforcing bar and a stainless steel bar. In this case, the ferrite unit 20
Although the structure and arrangement of are the same as in the first embodiment,
If reinforcing bars 43 are arranged in a grid along the grooves 16 of each ferrite unit 20 and along the gap in the electric field direction of the ferrite units 20, a fiber-reinforced concrete 40 (or CFRC 45) is cast. Good. The same or corresponding parts as in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

According to the third embodiment, the reinforcing bars 4
3 to increase the strength and to provide reinforcement 4
In 3, the radio wave reflector positioned behind the ferrite tile for operating as a ferrite radio wave absorber can also be used.

FIG. 9 shows a modification of the ferrite holding plate usable in the first, second and third embodiments. In this case, the ferrite pressing plate 15A made of an insulating lightweight foamed inorganic material such as a fiber-mixed foamed lightweight concrete has a cavity 17 opened on the front surface where the ferrite tile is mounted, formed in a portion where the groove 16 is not located. An insulative lightweight organic foam material 18 having a closed cell structure such as styrene foam having a specific gravity of 1.0 or less is provided.

According to the structure shown in FIG. 9, the ferrite pressing plate 15 is used to form a relatively lightweight foamed lightweight concrete or the like.
Even when used as A, there is an advantage that the weight can be further reduced.

Instead of inserting the lightweight insulating organic material 18 into the cavity 17 shown in FIG. 9, a hollow bag made of a resin or the like in which air is sealed may be inserted. Furthermore, when the ferrite tile can be bonded to the ferrite holding plate 15A so that the concrete does not enter the cavity 17, nothing is put in the cavity 17, and the concrete is put in the cavity 17 with air left. It can also be cast.

In each of the embodiments, the exterior tile is used. However, the use of the exterior tile is not an essential condition, and can be omitted, and can be replaced with another exterior material.

Although the embodiments of the present invention have been described above, it is obvious to those skilled in the art that the present invention is not limited to the embodiments and various modifications and changes can be made within the scope of the claims. There will be.

[0040]

As described above, according to the present invention,
Taking advantage of the original features of fiber-reinforced concrete with a new idea, a thin, lightweight concrete-integrated radio wave absorbing wall can be realized. In addition, sufficient strength can be ensured even without reinforcement as a structural material, and it can be easily used not only as a wall surface of a building but also as an outer wall material such as a pillar or a beam to prevent radio wave reflection, which is a great measure against TV ghosts in buildings. The effect is expected.

[Brief description of the drawings]

FIG. 1 is a plan sectional view showing a first embodiment of a thin radio wave absorbing wall according to the present invention.

FIG. 2 is a side sectional view of the same.

FIG. 3 is a rear view showing a state in which the metal reflector is omitted.

FIG. 4 is a perspective view showing a ferrite holding plate used in the first embodiment.

FIG. 5 is a perspective view showing a ferrite unit in which a ferrite tile is fixed to a ferrite holding plate in a magnetic field direction in the first embodiment.

FIG. 6 is a perspective view showing an arrangement of a plurality of ferrite units according to the first embodiment.

FIG. 7 is a plan sectional view showing a second embodiment of the present invention.

FIG. 8 is a perspective view showing an arrangement of a plurality of ferrite units and reinforcing bars according to a third embodiment of the present invention.

FIG. 9 is a perspective view showing a modified example of a ferrite pressing plate usable in the first to third embodiments.

FIG. 10 is a perspective view showing a conventional example of a radio wave absorbing wall having a structure to be fixed with an exterior tile with special feet.

FIG. 11 shows the VFRC on the front side of the ferrite plate and C on the back side.
It is a plane sectional view showing the conventional example of the electric wave absorption wall which has the metal reflective streak used as FRC.

FIG. 12 is a perspective view showing a structure in which a ferrite tile is fixed by a conventional ferrite pressing plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ferrite tile 2,30,35 Exterior tile 3 Reinforcing bar 4 Concrete 6 VFRC 7 Metal reflective bar 8,45 CFRC 10,15,15A Ferrite pressing plate 16 Depression groove 17 Cavity 18 Insulating lightweight organic foam material 20 Ferrite unit 31 Shear connector 32 Joint material 40 Fiber reinforced concrete 43 Reinforcing bar 50 Metal reflector

Continuation of the front page (56) References JP-A-52-122449 (JP, A) JP-A-55-52300 (JP, A) JP-A-60-94799 (JP, A) JP-A-1-274500 (JP) JP-A-2-202099 (JP, A) JP-A-6-61681 (JP, A) JP-A-8-37393 (JP, A) JP-A-64-10849 (JP, A) 3-48298 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) H05K 9/00

Claims (3)

(57) [Claims] 1. A thin radio wave absorbing wall in which ferrite units in which a ferrite tile is fixed to a ferrite pressing plate so as to be continuous in a magnetic field direction of an incoming radio wave are arranged at intervals in an electric field direction. A thin radio wave absorbing wall comprising a lightweight foam, wherein concave grooves along a direction of an electric field for arranging reinforcing ribs are repeatedly formed on said ferrite pressing plate at intervals in a direction of a magnetic field. 2. The thin electromagnetic wave absorbing wall according to claim 1, wherein fiber-reinforced concrete as a reinforcing rib material is provided between the ferrite units and in the concave groove and fixedly integrated. 3. The thin electromagnetic wave absorbing wall according to claim 1, wherein the ferrite pressing plate has a hollow portion, and a lightweight member having a specific gravity of 1.0 or less is inserted into the hollow portion.