JPH0837393A - Radio wave absorbing wall for building material - Google Patents

Abstract

PURPOSE:To make the band of the frequency characteristic of the reflection loss of a structure body of concrete, mortar, etc., wider and, at the same time, to constitute the structure body in a simple easily manufacturable structure so as to reduce the manufacturing cost of the structure body by suppressing the influence of the dielectric characteristic of the structure body on ferrite plates to a low level. CONSTITUTION:In the hollow sections 31 of a concrete panel 30 constituted in an insulating hollow structure body having the hollow sections 31 which are continuously formed in the direction of the magnetic field of arriving radio waves, ferrite plates 1 are continuously arranged in the direction of the magnetic field so that an air layer 35 can be formed behind the plates 1 when viewed from the arriving direction of the radio waves and a metallic mesh 38 is provided as a radio wave reflecting body behind the concrete panel 30.

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 for building materials used as a wall surface of a building as a measure for preventing radio wave reflection from the building such as prevention of television ghost.

[0002]

2. Description of the Related Art Conventionally, as a basic structure of a radio wave absorbing wall for building materials for preventing TV ghosts, there is a drainage type radio wave absorbing wall which combines magnetic characteristics of ferrite and radio wave characteristics. Such a drainboard type electromagnetic wave absorption wall is shown in FIG. 10 and FIG.
As in No. 1, the ferrite plates 1 are bonded so as to be continuous in the magnetic field direction of the radio wave and discontinuous in the electric field direction, and are attached to the metal plate 2 serving as the radio wave reflector with an adhesive. The structure of the electromagnetic wave absorption wall (first conventional example) and FIGS.
As described above, the ferrite plates 1 are continuously coupled in the magnetic field direction of the radio wave and discontinuous in the electric field direction, and the ferrite plate 1 is fixed to the metal plate 2 serving as a radio wave reflector by the pressing plate 3 and the bolts 4. A radio wave absorbing wall having a structure (second conventional example) is known.

The structure of these conventional electromagnetic wave absorbing walls is disclosed in Japanese Patent Publication No. 55-49798.
It is characterized in that a plurality of ferrite plates are continuously coupled in the magnetic field direction and are arranged with a gap (spaced) in the electric field direction.

In the case of the electromagnetic wave absorption wall having the above structure, practically, as a measure for preventing the ferrite plate from falling, a surface finishing material such as an exterior tile is attached to the surface of the ferrite plate by utilizing the gap in the electric field direction. A structure of a precast concrete wall in which concrete is cast on the back side of the ferrite plate 1 is used. 14 and 15 show the exterior tile 2 with special feet as a measure for preventing the ferrite plate 1 from falling.
1 shows a conventional three-layer concrete integrated type electromagnetic wave absorption wall (third conventional example) having a structure for fixing with 1. In this case, the ferrite plate 1 is arranged on the front surface of the reinforcing bar 20 forming the metal reflection mesh (radio wave reflector) so as to be continuous in the magnetic field direction and discontinuous in the electric field direction, and the exterior tile with special feet (porcelain tile etc.) By covering 21 on the front surface of the ferrite plate 1 and placing concrete 22 on the back surface side, a radio wave absorbing wall of the precast concrete plate is constructed.

By the way, the outer wall of a building or the like is generally made of concrete and an exterior material.
When the structure shown in FIG. 5 is adopted, the characteristics as a radio wave absorber are greatly affected by the dielectric constant and thickness of the concrete on the back side of the ferrite plate 1 and the exterior material on the front side of the ferrite plate 1. In addition, there are trade-offs between durability and strength as a building material, and the characteristics and thickness of the ferrite plate are selected within strict design constraints.

First, referring to FIG. 16, in the basic configuration of the ferrite electromagnetic wave absorber, that is, in the structure in which the back surface of the ferrite plate 1 is lined with the metal plate (reflector) 2, the electromagnetic wave absorption characteristics with respect to the thickness t1 of the ferrite plate. An example is shown. The frequency of the radio wave used at this time is 100 MHz. FIG.
It can be seen from Fig. 6 that the thickness t1 of the ferrite plate 1 is about 7 mm and the return loss is 30 dB or more.

Next, using a ferrite plate 1 having a thickness of 7 mm,
When the back surface of the ferrite plate 1 is lined with a metal plate 2 and the front surface of the ferrite plate 1 is loaded (added) with a mortar 6 having a dielectric constant of about 5 to form a radio wave absorber, the thickness of the mortar 6 The change in the characteristics of the electromagnetic wave absorber with respect to t2 is shown by the solid line (a) in FIG. In the case of no mortar 6 (t2 = 0 mm), a radio wave absorption characteristic of 30 dB or more is shown, but it can be seen that as the thickness t2 of the mortar 6 is increased, it is significantly deteriorated.

The dotted line (b) in FIG. 17 shows the electromagnetic wave absorption characteristics of the electromagnetic wave absorber when a similar mortar 6 is inserted between the ferrite plate 1 and the metal plate 2 behind it. Significant deterioration of characteristics is recognized more than when the mortar 6 is provided on the front surface of the ferrite plate 1 shown by the solid line (a) (especially in the region where the thickness t2 is 15 mm or more).

In the case of the conventional three-layer concrete integral type electromagnetic wave absorption wall shown in FIGS. 14 and 15, the radio wave depends on the dielectric constant and thickness of the concrete on the back side of the ferrite plate and the exterior material on the front side of the ferrite plate. As a result of the large influence of the characteristics of the absorber, the frequency characteristics of return loss are shown in Fig. 1.
The curve (b) of Fig. 8 shows a radio wave absorption characteristic of about 20 dB in a narrow frequency band near 100 MHz, but it is found that it is significantly deteriorated in other frequency bands (the frequency characteristic of return loss is Shows narrow band characteristics.).

[0010]

The problem of the electromagnetic wave absorbing wall for building materials is how to simplify the structure to reduce the manufacturing cost and to secure the necessary and sufficient electromagnetic wave absorbing characteristics.

(1) Although not particularly mentioned in the description of the conventional three-layer concrete integrated type electromagnetic wave absorbing wall of FIGS. 14 and 15, the manufacturing process of such a building material electromagnetic wave absorbing wall is the same as that of the conventional concrete panel manufacturing. Separately from the process, it is necessary to continuously arrange a plurality of ferrite plates in the magnetic field direction of the incoming radio wave, and this array does not move during concrete pouring, and each ferrite plate must be in close contact. Desired. As a countermeasure against this, for example, JP-A-64
As shown in No. 10849, fixing work such as pressure bonding of ferrite plates is actually required.

(2) As shown in (a) and (b) of FIG. 17 described above, this type of electromagnetic wave absorbing wall is not deteriorated by the dielectric characteristics of the exterior material or the like attached to the front surface of the ferrite plate, rather than being deteriorated by the ferrite. The deterioration of the dielectric properties due to the concrete placed on the back of the plate is large. How to reduce the influence of this dielectric property, and how to reduce the apparent effective permittivity when the thickness is required are required. Therefore, it is possible to actually thin the concrete on the back side of the ferrite plate. However, the concrete provided on the back side of the ferrite plate is usually used as an outer wall material from the viewpoint of durability and strength.
It is difficult to reduce the thickness because a thickness close to mm is required. At present, this characteristic deterioration is dealt with by controlling the magnetic characteristics of the ferrite plate (such as slit insertion) and controlling the thickness of the ferrite plate. However, there is a trade-off between durability and strength as a building material, and it is necessary to select suitable magnetic characteristics, thickness, etc. of the ferrite plate within the severe design constraints.
As shown by the curve (b) in (1), the frequency characteristic of the return loss becomes a narrow band characteristic, and it is difficult to secure a sufficient return loss over a wide frequency range.

In view of the above points, the present invention suppresses the influence of the dielectric characteristics of the structure such as concrete or mortar on the ferrite plate to a small extent to widen the frequency band of the return loss and has a simple structure. An object of the present invention is to provide an electromagnetic wave absorbing wall for building materials, which is easy to manufacture and can reduce the cost.

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

[0015]

In order to achieve the above object, a building material radio wave absorption wall of the present invention has an insulating hollow structure having a hollow portion continuous in the magnetic field direction of an incoming radio wave, The ferrite plate is arranged continuously in the magnetic field direction so that an air layer exists behind the ferrite plate when viewed from the direction of arrival of radio waves, and the radio wave reflector is arranged behind the insulating hollow structure.

In the construction of the radio wave absorbing wall for building materials described above, a convex portion for regulating the position of the ferrite plate may be provided in the hollow portion.

Further, the insulating hollow structure may be a hollow extrusion molded product in which a plurality of hollow portions continuous in the magnetic field direction of the incoming radio wave are provided at intervals in the electric field direction of the incoming radio wave.

Further, the air layer may have a thickness dimension larger than that of the ferrite plate.

[0019]

In the electromagnetic wave absorbing wall for building materials according to the present invention, the insulating hollow structure (a material that functions as a dielectric against incoming radio waves and does not reflect radio waves) is located behind the ferrite plate when viewed from the radio wave incoming direction. The ferrite plate is arranged continuously in the direction of the magnetic field so that there is an air layer, and the structure with a large dielectric constant such as concrete or mortar does not come into direct contact with most of the back surface of the ferrite plate, and the air layer is Will intervene. As a result, since the air layer and the rear part of the insulating hollow structure are formed between the back surface of the ferrite plate and the radio wave reflector, the effective permittivity behind the ferrite plate is lowered and the ferrite plate The deterioration of the electromagnetic wave absorption characteristics can be suppressed to a small level, and the electromagnetic wave absorption characteristics can be improved compared to the conventional structure in which almost the entire surface of the ferrite plate is surrounded by concrete, mortar, etc. The degree of freedom in selecting the thickness is increased, and the band of the electromagnetic wave absorption characteristics can be widened.

Further, when the ferrite plate is arranged, the hollow portion which is continuous in the magnetic field direction can be used as an alignment guide for the ferrite plate, and the ferrite plate can be prevented from falling. At the time of
Since there is no work to fix the ferrite plates so that they do not move, the manufacturing process can be simplified, the manufacturing becomes easy, and the cost can be reduced.

Further, in the conventional structure in which concrete is cast around the ferrite plate and surrounds the ferrite plate, there is a risk that the magnetic characteristics will be deteriorated due to a force being applied to the ferrite plate due to the contraction rate when hardening the concrete. However, since the ferrite plate is arranged in the hollow portion of the insulating hollow structure, there is no fear of deterioration of magnetic characteristics.

Further, when the hollow portion is provided with a convex portion for regulating the position of the ferrite plate, the convex portion can surely align and hold the ferrite plate in a continuous state in the magnetic field direction of the incoming radio wave. Prevents the plate from falling.

In the case where the insulating hollow structure is constituted by a hollow extruded product having a plurality of hollow portions continuous in the magnetic field direction of the incoming radio wave at intervals in the electric field direction of the incoming radio wave, the insulating hollow structure is Can be easily manufactured at low cost by the hollow extrusion molding method.

Further, when the air layer has a thickness larger than the thickness of the ferrite plate, the effective dielectric constant can be sufficiently lowered, and the return loss of radio waves and the return loss are increased. It is possible to further widen the band of the frequency characteristic of the quantity.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the electromagnetic wave absorbing wall for building material 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 plan sectional view of the first embodiment, and shows a state in which a radio wave absorbing wall for building materials is attached to a structural body. Also, FIG.
Is a perspective view showing the back side of the electromagnetic wave absorbing wall for building materials, FIG. 3 is a side cross-section, and FIG. 4 is a perspective view showing a hollow extruded concrete panel as an insulating hollow structure used in the first embodiment. FIG. 5 is a partially enlarged view of FIG. 1 (or a cement panel).

In these figures, a hollow extruded concrete panel (or cement panel) 30 penetrates in the magnetic field direction of the incoming radio wave (direction perpendicular to the plane of FIG. 1) in order to fit and hold the ferrite plate 1. Hollow part 31 that continues)
Are provided at intervals in the electric field direction of the incoming radio wave, and a hollow extrusion molded product (width about 600 mm, length several m, with a fitting recess 32 on one side and a fitting protrusion 33 on the other side) is formed. The total thickness is 60 mm). The ferrite plate 1 used here has, for example, a width of 50 to 60 mm and a length of 10
It has a ferrite tile shape such as a rectangle with a thickness of 0 mm and a thickness of 7 to 10 mm.

The hollow portion 31 has a lateral width slightly larger than the lateral width of the ferrite plate 1 so that the ferrite plate 1 can be fitted and held, and a convex portion 34 for restricting the position of the ferrite plate 1 is provided. It is provided so as to project to the middle portion of both inner side surfaces. The hollow portion 31 is divided into a front space portion and a rear space portion when viewed from the direction of arrival of the radio wave by the paired convex portions 34, and the ferrite plate 1 can be held in the front space portion as shown in FIG. As shown in FIG. 5, the space between the front inner surface 31a of the hollow portion 31 and the front surface 34a of the convex portion 34 is formed to be slightly larger than the thickness of the ferrite plate 1. Further, between the front surface 34a of the convex portion 34 and the rear inner surface 31b of the hollow portion 31, there is an air layer 35 in which air is present in the space even after the ferrite plate 1 is arranged, and the thickness of the air layer 35 is It is sufficiently larger than the thickness of the ferrite plate 1 and larger than the thickness of concrete on the panel back side.

Then, an adhesive 37 is applied between the hollow portion 31 and the front surface and both side surfaces of the ferrite plate 1 to form each hollow portion 3
The ferrite plate 1 is fitted in the front space of 1 without gap in the magnetic field direction of the incoming radio wave, and the end faces of the ferrite plate 1 are brought into close contact with each other and continuously connected and held in the magnetic field direction. At this time, the upper and lower openings of the hollow portion 31 are fixed so that the end surface of the ferrite plate 1 and the opening surface of the hollow portion 31 are flush with each other.

The arrangement interval of the incoming radio waves in the hollow portion 31 in the electric field direction is set to an interval at which sufficient radio wave absorption characteristics are obtained when the ferrite plate 1 is arranged.

The hollow extruded concrete panel 3
In order to attach 0 to a structural frame 39 such as a steel frame of a building, the hollow extruded concrete panel 30 is penetrated from the back surface into the hollow part 31 at the opening end of the hollow part 31 located on both sides of the hollow extruded concrete panel 30. A through hole 36 is provided.

Then, a metal mesh 38 as a radio wave reflector is arranged on the back surface of the hollow extruded concrete panel 30 to which the ferrite plate 1 is fixed, and a structural frame 39 such as a steel frame for construction is located behind it. The hollow extruded concrete panel 30 is attached and fixed to the structural body 39. The metal mesh 38 is, for example, fixed in advance to the structural skeleton 39, and the bolt 41 is inserted into the connecting fitting 40 locked to the structural skeleton 39 and the through hole 36 of the hollow extruded concrete panel 30, and the bolt 41 is a nut. Four
The hollow extruded concrete panel 30 is attached to the structural body 39 by screwing 2 and tightening.

The hollow extruded concrete panel 3
A plurality of 0s are connected in the left-right direction or the up-down direction according to the desired size of the electromagnetic wave absorption wall, and are held by the structural body 39 to which the metal mesh 38 is fixed. The hollow extruded concrete panels 30 are connected in the left-right direction by fitting and fixing the fitting recesses 32 and the fitting projections 33 on the side faces of the adjacent hollow extruded concrete panels 30, as shown in FIG. Further, in the vertical connection, the end faces of the ferrite plate 1 facing the opening surface of the hollow portion 31 of the hollow extruded concrete panel 30 facing each other are brought into close contact with each other, and the ferrite plate 1 is connected seamlessly in the magnetic field direction of the incoming radio wave. It is desirable to let

When the side wall of the building is actually constructed of a radio wave absorbing wall for building materials, the lower end of the hollow portion 31 of the hollow extruded concrete panel 30 at the lowermost end is used to ensure the fixation of the ferrite plate 1. It is advisable to fill it up with concrete, etc. (to prevent the ferrite plate from sliding down) and close it.

Here, the electromagnetic wave absorption characteristics (frequency characteristics of return loss) of the building electromagnetic wave absorption wall of the first embodiment obtained by the above configuration are shown in the curve (a) of FIG. 10mm thickness, 14mm concrete thickness on the front side of the ferrite plate, 20mm air layer thickness, 14mm concrete thickness behind). Compared with the curve (b) of FIG. 18, which is the radio wave absorption characteristic of the conventional representative three-layer structure radio wave absorption wall shown in FIGS. 14 and 15 described above, the radio wave absorption of the first embodiment according to the present invention is performed. It can be seen that the wall is excellent in both the amount of radio wave absorption and the frequency characteristic.

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

(1) Hollow extrusion molded concrete panel 3
Since the ferrite plate 1 is continuous in the magnetic field direction of the incoming radio wave in the hollow portion 31 of 0, and the air layer 35 is located behind when seen from the incoming direction of the radio wave, the permittivity of concrete or the like is large. Suppress the effect, ferrite plate 1
The effective permittivity between the metal mesh 38 and the metal mesh 38 serving as a radio wave reflector can be lowered to suppress deterioration of the radio wave absorption characteristics of the ferrite plate to a small level, and the radio wave absorption characteristics can be broadened. Therefore, compared with the conventional structure in which the periphery of the ferrite plate is surrounded by concrete or mortar, the electromagnetic wave absorption characteristics are significantly improved, and VHF, UH
An electromagnetic wave absorbing wall for building materials for ghost interference prevention, which exhibits excellent electromagnetic wave absorption characteristics over 100 MHz to 500 MHz where F so-called ghost interference is likely to occur, is obtained.

The dimension of the air layer 35 in the thickness direction is set to be sufficiently larger than the thickness of the ferrite plate 1 and sufficiently larger than the wall thickness of the hollow extruded concrete panel 30 on the rear side. The effect of suppressing the influence of concrete or the like having a large dielectric constant on the plate 1 and the effect of lowering the effective dielectric constant between the ferrite plate 1 and the metal mesh 38 can be sufficiently fulfilled, and the effect of improving the electromagnetic wave absorption characteristics is remarkable. can do.

(2) The hollow extrusion molded concrete panel 30 having a plurality of hollow portions 31 can be easily manufactured at low cost by the hollow extrusion molding method. This hollow extruded concrete panel 30 has a hollow portion 31 in which the ferrite plate 1 is arranged.
Since it has a hollow structure and has sufficient strength, it is not necessary to place concrete for fixing the ferrite plate 1. Using such an inexpensive concrete panel, the hollow portion 31 is provided with an alignment guide for the ferrite plate 1 and the ferrite plate 1.
By using it as a fall prevention device, the ferrite plate alignment step can be omitted, and the steps can be shortened and the cost can be reduced.

(3) In the conventional structure in which concrete is cast around the ferrite plate 1 and surrounds the ferrite plate, magnetic force may be deteriorated due to a force being applied to the ferrite plate due to the shrinkage ratio when hardening the concrete. However, in this embodiment, since the ferrite plate 1 is fitted and fixed in the hollow portion 31 of the hollow extruded concrete panel 30 after molding and hardening, there is no fear of deterioration of magnetic characteristics.

(4) Since the hollow portion 31 is provided with the pair of convex portions 34 for regulating the ferrite plate position, the ferrite plate 1 has the front surface 34a of the convex portion 34 and the front inner surface 31a of the hollow portion 31 as shown in FIG. It is possible to position it in the front space of the hollow portion 31 by fitting it between the two, and to easily and reliably align and hold the ferrite plate 1 in a continuous state in the magnetic field direction of the incoming radio wave. Therefore, when placing concrete with the conventional structure, it is not necessary to fix the ferrite plates 1 so as not to move, and the manufacturing process can be simplified and the manufacturing becomes easy. Therefore, combined with the effect of the above item (2), a significant cost reduction can be achieved.

The adhesive 37 used in the first embodiment is used.
Is a ferrite plate 1 hollow extrusion molded concrete panel 3
It suffices if it can be temporarily fixed in the hollow portion 31 of 0, and once the building material electromagnetic wave absorption wall is assembled as the side wall of the building, the ferrite 1 is held in a state in which the position is regulated by the pair of convex portions 34. It is only necessary to securely prevent the ferrite plate 1 from falling.

6 and 7 show a second embodiment of the present invention. In this case, even if the step difference between the hollow portion 31 of the hollow extruded concrete panel 30 and the ferrite plate 1 fixed to the inside is slightly large, the ferrite plate 1 is aligned without any rattling in the magnetic field direction of the incoming radio wave. It is possible. That is, a pair of fixing members 50 are used for fitting and fixing the ferrite plate 1 in the hollow portion 31. The fixing member 50 is formed by molding an insulating inorganic material (organic material can be used, but inorganic material is preferable when fire resistance is taken into consideration) so that the plane cross section is substantially L-shaped. In this case, the ferrite plate 1 is disposed in the front space defined by the pair of convex portions 34 of the hollow portion 31, and the front inner surface 31a of the hollow portion 31 and the front surface 34a of the convex portion 34 are arranged as shown in FIG.
The ferrite plate 1 is fitted between and, and a pair of fixing members 50 are inserted so as to fill the gap between the ferrite plate 1 and the hollow portion 31. That is, the ferrite plate 1
The ferrite plate 1 is fitted and fixed in the hollow portion 31 of
The fixing members 50 are respectively interposed between the corners on the front surface side of the hollow portion 31 and the corners on the front surface side of the hollow portion 31, and the adhesive 37 is provided in the gap where the hollow portion 31 and the front surface of the ferrite plate 1 face each other.

According to the second embodiment, even when the width of the hollow portion 31 of the hollow extruded concrete panel 30 is set to be slightly larger than the width of the ferrite plate 1,
There is an advantage that the ferrite plates 1 can be aligned without rattling and can be applied even when the dimensional accuracy of the hollow extruded concrete panel 30 is low.

The rest of the configuration, operation and effect are the same as those of the first embodiment described above, and the same or corresponding members are designated by the same reference numerals and their description is omitted.

FIG. 8 shows a third embodiment of the present invention. In this case, the hollow extruded concrete panel 30A as an insulating hollow structure is provided with a plurality of hollow portions 31A having a substantially rectangular cross section so as to penetrate in the magnetic field direction of the incoming radio wave at intervals in the electric field direction of the incoming radio wave. There is. Then, the ferrite plate 1 is fixed to the hollow portion 31A by applying an adhesive agent 37 between the hollow portion 31A and the front surface and both side surfaces of the ferrite plate 1,
This is performed by attaching the ferrite plate 1 to the front surface side of the hollow portion 31A.

In the case of the third embodiment, the shape of the hollow portion 31A of the hollow extruded concrete panel 30A is simple, the hollow extruded concrete panel can be easily manufactured, and in some cases, the commercially available hollow extruded concrete is used. There is an advantage that the panel can be used as it is.

The rest of the configuration, operation and effects are the same as those of the first embodiment described above, and the same or corresponding members are designated by the same reference numerals and their description is omitted.

In the third embodiment, instead of applying the adhesive 37, an inorganic adhesive such as mortar is applied to the ferrite plate 1 in a state in which the ferrite plates 1 in the hollow portion 31A are horizontally arranged during manufacturing. It is also possible to fix the ferrite plates 1 by pouring them into the hollow portion so as to be slightly higher than the thickness.

FIG. 9 shows a fourth embodiment of the present invention. In this case, in order to fix the ferrite plate 1 to the hollow portion 31A having a substantially rectangular cross section of the hollow extruded concrete panel 30A similar to that of the third embodiment, a pair of square bar-shaped pad members 51 are used.
Is used. The patch 51 is made of the same material as the hollow extruded concrete panel 30A or another insulating material. In this case, ferrite plate 1
When fixing to the hollow portion 31A, the backing material 51 is interposed between the rear surface of both ends of the ferrite plate 1 and the rear surface of the hollow portion 31A so that the ferrite plate 1 abuts on the front surface side of the hollow portion 31A. It is regulated and fixed. That is, the adhesive 37 is applied between the ferrite plate 1 and the pad material 51 and the hollow portion 31A, respectively.
The ferrite plate 1 and the pad material 51 are adhered and fixed to the inner surface.

Also in the case of the fourth embodiment, the shape of the hollow portion 31A of the hollow extrusion molded concrete panel 30A is simple and the hollow extrusion molded concrete panel is easy to manufacture. There is an advantage that the concrete panel can be used as it is. Moreover, by using the square bar-shaped pad material 51, it is easy to secure the fixing strength of the ferrite plate 1.

The rest of the configuration, operation and effects are the same as in the first embodiment described above, and the same or corresponding members are assigned the same reference numerals and their explanations are omitted.

Although the hollow extruded concrete panels 30 and 30A are not provided with an exterior material on the front surface in each of the above-described embodiments, the hollow extruded concrete panels 30 and 30A are provided on the front surface with a paint or resin as an exterior material. A coating / spraying material such as mortar may be added.

In each embodiment, the metal mesh 38 is used as the radio wave reflector placed behind the hollow extruded concrete panels 30 and 30A, but a metal sheet is attached to the back surface of the hollow extruded concrete panels 30 and 30A. Alternatively, a configuration in which a conductive paint is applied may be used.

In each embodiment, the metal mesh 38, which is a radio wave reflector, is fixed to the structural body 39 in advance,
When the hollow extruded concrete panels 30 and 30A are fixed to the structural body 39, the hollow extruded concrete panels 30 and 30A are located on the back side of the hollow extruded concrete panels 30 and 30A. Before being cured, a metal mesh 39 is provided on the back surface of the hollow extruded concrete panel 30, 30A.
You may press and integrate.

Further, in each of the embodiments, a hollow extruded concrete panel (cement panel) is exemplified as the insulating hollow structure, but it has strength as a building material and functions as a dielectric for incoming radio waves. Any material that does not reflect radio waves may be used, and a ceramic structure obtained by firing a ceramic material after hollow extrusion molding may be used.

Although the embodiment of the present invention has been described above, it is obvious to those skilled in the art that the present invention is not limited to this and various modifications and changes can be made within the scope of the claims. Let's do it.

[0058]

As described above, according to the radio wave absorbing wall for building materials of the present invention, the ferrite is such that there is an air layer behind the ferrite plate in the hollow part of the insulating hollow structure as seen from the radio wave arrival direction. Since the plates are arranged continuously in the magnetic field direction, the effective permittivity behind the ferrite plate is reduced, deterioration of the electromagnetic wave absorption characteristics of the ferrite plate can be suppressed to a small level, and the electromagnetic wave absorption characteristics can be improved. It is possible to widen the band of the radio wave absorption characteristics.

Further, when the ferrite plate is arranged, the hollow portion continuous in the magnetic field direction can be used as an alignment guide for the ferrite plate, and the ferrite plate can be prevented from falling, which simplifies the manufacturing process. It is possible,
Manufacturing becomes easy.

Further, since the ferrite plate is arranged in the hollow portion of the insulating hollow structure, there is no fear that the magnetic properties will be deteriorated due to stress applied to the ferrite plate.

Therefore, it is possible to obtain the electromagnetic wave absorbing wall for building material which has sufficient strength as a wall material for building material, realizes a necessary and sufficient wide band electromagnetic wave absorbing property, and is easy to manufacture and inexpensive and suitable for the countermeasure against ghost interference.

[Brief description of drawings]

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

FIG. 2 is a perspective view showing a back side of a radio wave absorbing wall for building materials used in the first embodiment.

FIG. 3 is a side sectional view showing a first embodiment.

FIG. 4 is a perspective view showing a hollow extrusion-molded concrete panel used in the first embodiment.

FIG. 5 is a partially enlarged plan sectional view showing the first embodiment.

FIG. 6 is a plan sectional view showing a second embodiment of the present invention.

FIG. 7 is an enlarged plan sectional view of the same portion.

FIG. 8 is a partially enlarged plan sectional view showing a third embodiment of the present invention.

FIG. 9 is a partially enlarged plan sectional view showing a fourth embodiment of the present invention.

FIG. 10 is a plan view showing a first conventional example of a radio wave absorption wall in which a ferrite plate is arranged which is continuous in the magnetic field direction and discontinuous in the electric field direction.

FIG. 11 is a front view of the same.

FIG. 12 is a plan view showing a second conventional example of a radio wave absorption wall in which a ferrite plate is arranged which is continuous in the magnetic field direction and discontinuous in the electric field direction.

FIG. 13 is a front view of the same.

FIG. 14 is a perspective view showing a third conventional example of a radio wave absorption wall having a structure of fixing with an exterior tile with special feet.

FIG. 15 is a plan sectional view of the same.

FIG. 16 is a graph showing radio wave absorption characteristics in the basic configuration of the radio wave absorption wall.

FIG. 17 is a graph showing radio wave absorption characteristics when mortar is loaded on the basic structure of the radio wave absorption wall.

FIG. 18 is a graph showing radio wave absorption characteristics of the first embodiment of the present invention and the third conventional example.

[Explanation of symbols]

 1 Ferrite Plate 2 Metal Plate 30, 30A Hollow Extrusion Molded Concrete Panel 31, 31A Hollow Part 32 Fitting Concave Part 33 Fitting Convex Part 34 Convex Part 35 Air Layer 36 Through Hole 37 Adhesive 38 Metal Mesh 39 Structural Body 40 Connecting Metal Fitting 50 Fixing member 51 Pad material

Claims (4)

[Claims] 1. The ferrite plate in the magnetic field direction such that an air layer is present behind the ferrite plate when viewed from the radio wave arrival direction in the hollow part of the insulating hollow structure having a hollow part continuous in the magnetic field direction of the incoming radio wave. A radio wave absorbing wall for building material, characterized in that the radio wave reflecting body is placed behind the insulating hollow structure. 2. The electromagnetic wave absorbing wall for building materials according to claim 1, wherein a convex portion that regulates the position of the ferrite plate is provided in the hollow portion. 3. The insulative hollow structure is a hollow extrusion molded product in which a plurality of hollow portions continuous in the magnetic field direction of the incoming radio wave are provided at intervals in the electric field direction of the incoming radio wave.
Alternatively, the electromagnetic wave absorbing wall for building material according to 2. 4. The radio wave absorbing wall for building material according to claim 1, wherein the air layer has a thickness larger than a thickness of the ferrite plate.