JP2791937B2 - Radio wave absorption wall for building materials - 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 for a building material used for a wall surface of a building as a measure for preventing reflection of a radio wave by a building such as a television ghost prevention.

[0002]

2. Description of the Related Art Hitherto, as a basic structure of a radio wave absorbing wall for building materials for preventing television ghost, there is a snowboard type radio wave absorbing wall which combines the magnetic properties of ferrite and the properties of radio waves. As such a saw-shaped radio wave absorbing wall, as shown in FIGS. 8 and 9 , the ferrite plate 1 is coupled so as to be continuous in the direction of the magnetic field of the radio wave and is arranged to be discontinuous in the direction of the electric field. A radio wave absorbing wall (first conventional example) having a structure in which the ferrite plate 1 is continuously bonded in the direction of a radio wave magnetic field as shown in FIGS. There is known a radio wave absorbing wall (second conventional example) having a structure in which a ferrite plate 1 is fixed to a metal plate 2 serving as a radio wave reflector with a pressing plate 3 and bolts 4 in a discontinuous arrangement in a direction.

[0003] The structure of these conventional radio wave absorption 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 direction of the magnetic field, and are arranged with a gap (at intervals) in the direction of the electric field.

In the case of the radio wave absorbing wall having the above-described structure, a surface finishing material such as an exterior tile is attached to the surface of the ferrite plate by using a gap in the direction of the electric field as a practical measure to prevent the ferrite plate from falling. A precast concrete wall structure in which concrete is cast on the back side of the ferrite plate 1 is used. FIGS. 12 and 13 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 radio wave absorbing wall (third conventional example) having a structure fixed at 1. In this case, the ferrite plate 1 is arranged in front of the reinforcing bar 20 forming a metal reflection mesh (radio wave reflector) so as to be continuous in the direction of the magnetic field and discontinuous in the direction of the electric field. 21 is placed on the front surface of the ferrite plate 1 and concrete 22 is cast on the back side to constitute a radio wave absorption wall of a precast concrete plate.

[0005] The outer wall of a building or the like is generally made of concrete and an exterior material .
In the case of the structure shown in FIG. 3 , 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 greatly affect the characteristics as a radio wave absorber. In addition, there is a trade-off between durability and strength as a building material, and the characteristics, thickness, and the like of the ferrite plate are selected under strict design restrictions.

First, in FIG. 14 , the basic structure of the ferrite radio wave absorber, that is, the radio wave absorption characteristics with respect to the thickness t1 of the ferrite plate in the structure in which the back surface of the ferrite plate 1 is lined with the metal plate (reflector) 2 An example is shown below. The frequency of the radio wave used at this time is 100 MHz. FIG.
4 shows that the ferrite plate 1 has excellent characteristics with a return loss of 30 dB or more when the thickness t1 of the ferrite plate 1 is about 7 mm.

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

The dotted line (b) in FIG. 15 shows the radio wave absorption characteristics of the radio wave absorber when the same mortar 6 is inserted between the ferrite plate 1 and the metal plate 2 behind. Compared to the case where the mortar 6 is provided on the front surface of the ferrite plate 1 shown by the solid line (a), the characteristic deterioration is remarkably recognized (especially in a region where the thickness t2 is 15 mm or more).

In the case of the conventional three-layer concrete integrated radio wave absorbing wall shown in FIGS. 12 and 13 , the radio wave is determined by 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, the frequency characteristics of the return loss are shown in FIG.
As shown in the curve (b) of FIG. 6 , the radio wave absorption characteristic of about 20 dB is shown in a narrow frequency band around 100 MHz, but it can be seen that it is significantly deteriorated in other frequency bands (the frequency characteristic of the return loss is It shows a narrow band characteristic.).

[0010]

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

(1) Although not particularly described in the description of the conventional three-layer concrete integrated radio wave absorbing wall in FIGS . 12 and 13 , the manufacturing process of such a building material radio wave absorbing wall is as follows.
Apart from the conventional concrete panel manufacturing process, it is necessary to arrange a plurality of ferrite plates continuously in the magnetic field direction of the arriving radio wave. Is required. As a countermeasure against this, for example,
As shown in JP-A-4-10849, a fixing operation such as pressure bonding between ferrite plates is actually required.

(2) FIGS. 15A and 15B described above .
As shown in (1), this type of radio wave absorption wall is more greatly deteriorated by the dielectric characteristics of the concrete disposed on the rear surface of the ferrite plate than by the dielectric characteristics of an exterior material attached to the front surface of the ferrite plate. It is required to reduce the influence of the dielectric properties, and to reduce the apparent effective permittivity if the thickness is required. Therefore, it is conceivable to actually reduce the thickness of 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 in view 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 controlled by controlling the magnetic properties 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 the magnetic properties and thickness of the ferrite plate must be selected under strict design constraints .
As shown in the curve (b) of FIG. 6 , the frequency characteristic of the return loss is a narrow band characteristic, and it is difficult to dislike to secure a sufficient return loss over a wide frequency range.

In view of the above, the present invention suppresses the influence of the dielectric characteristics of a structure such as concrete or mortar on a ferrite plate to reduce the frequency characteristics of the return loss and achieve a wide band. It is an object of the present invention to provide a radio wave absorbing wall for building materials which is easy to manufacture and can reduce costs.

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 radio wave absorbing wall for a building material according to the present invention has a hollow portion continuous in the magnetic field direction of an incoming radio wave with an interval in the electric field direction of the incoming radio wave.
In each hollow part of the multiple insulating hollow structures , ferrite
Providing a convex part that regulates the position of the board
Partitioning into a front space portion and a rear space portion as viewed from the
The ferrite plate as seen from DOA said by continuously to the magnetic field direction as the air layer is present behind the ferrite plate
The radio wave reflector is arranged to fit in the front space portion and to be located behind the insulating hollow structure.

[0016]

[0017]

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

[0019]

In the radio wave absorbing wall for building materials of the present invention, the hollow portion of the insulating hollow structure (material that functions as a dielectric against incoming radio waves and does not reflect radio waves) is located behind the ferrite plate as viewed from the radio wave arrival direction. The ferrite plate is arranged continuously in the direction of the magnetic field so that there is an air layer in the surface of the ferrite plate, and a structure with a large dielectric constant, such as concrete or mortar, does not directly contact most of the back of the ferrite plate. It will intervene. As a result, the gap between the rear surface of the ferrite plate and the radio wave reflector is formed by the air layer and the rear part of the insulating hollow structure, so that the effective dielectric constant behind the ferrite plate decreases, Deterioration of the radio wave absorption characteristics can be suppressed to a small extent, and the radio wave absorption characteristics can be improved compared to a structure in which almost the entire surface of the conventional ferrite plate is surrounded by concrete, mortar, etc., and at the same time, the characteristics and the thickness of the ferrite plate The degree of freedom in selecting the thickness is increased, and the radio wave absorption characteristics can be broadened.

Further, when the ferrite plate is provided, a 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 dropping. At the time
There is no work of fixing the ferrite plates so as not to move, so that 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, magnetic properties may be degraded due to, for example, a force applied to the ferrite plate due to the shrinkage ratio at the time of concrete hardening. However, since the ferrite plate is disposed in the hollow portion of the insulating hollow structure, there is no fear of deterioration in magnetic characteristics.

In the case where the hollow portion is provided with a convex portion for regulating the position of the ferrite plate, the convex portion can reliably align and hold the ferrite plate in a continuous state in the magnetic field direction of the arriving radio wave. The effect of preventing the plate from falling is also ensured.

Further, when the insulating hollow structure is constituted by a hollow extruded product in which a plurality of hollow portions continuous in the magnetic field direction of the arriving radio wave are provided at intervals in the electric field direction of the arriving radio wave, Can be easily manufactured at low cost by a hollow extrusion molding method.

When the air layer has a thickness greater than the thickness of the ferrite plate, the effective dielectric constant can be sufficiently reduced, and the return loss of radio waves increases and the return loss increases. The amount of frequency characteristics can be further broadened.

[0025]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an embodiment of a radio wave absorbing wall for building materials according to the present invention.

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, showing a state in which a radio wave absorbing wall for building material is attached to a structural body. FIG.
3 is a perspective view showing the back side of the radio wave absorbing wall for building materials, FIG. 3 is a side sectional view, 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.

In these figures, a hollow extruded concrete panel (or cement panel) 30 penetrates in the magnetic field direction of incoming radio waves (direction perpendicular to the plane of FIG. 1) in order to fit and hold the ferrite plate 1. Continuous) hollow part 31
Are provided at intervals in the direction of the electric field of the arriving radio wave, and a hollow extruded product having a fitting concave portion 32 on one side and a fitting convex portion 33 on the other side (width of about 600 mm, length of several meters, 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 mm.
It is a ferrite tile shape such as a rectangle having a thickness of 0 mm and a thickness of 7 to 10 mm.

The hollow portion 31 has a width slightly larger than the width of the ferrite plate 1 so that the ferrite plate 1 can be fitted and held therein. It protrudes and is provided in the middle part of both inner side surfaces. The hollow portion 31 is partitioned into a front space portion and a rear space portion as viewed from the radio wave arrival direction by the pair of convex portions 34, and the ferrite plate 1 can be held in the front space portion as shown in FIGS. As shown in FIG. 5, the gap 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 remains in the space even after the ferrite plate 1 is provided, and the thickness of the air layer 35 is The thickness is sufficiently larger than the thickness of the ferrite plate 1 and larger than the thickness of the concrete on the back side of the panel.

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

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

The hollow extruded concrete panel 3
0 is attached to the structural frame 39 such as a steel frame of the building, and the hollow extruded concrete panel 30 is positioned near the open end of the hollow panel 31 on both sides thereof. A through hole 36 is provided.

A metal mesh 38 as a radio wave reflector is disposed on the back 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 a building is positioned behind the metal mesh 38. The hollow extruded concrete panel 30 is attached to the structural frame 39 and fixed. The metal mesh 38 is fixed to, for example, a structural frame 39 in advance, and a bolt 41 is inserted into the through hole 36 of the connection fitting 40 and the hollow extruded concrete panel 30 locked by the structural frame 39, and a nut is inserted into the bolt 41. 4
The hollow extruded concrete panel 30 is attached to the structural frame 39 by screwing and tightening 2.

The hollow extruded concrete panel 3
Numerals 0 are connected to each other in the left-right direction or the up-down direction according to the desired size of the radio wave absorption wall, and are held by the structural frame 39 to which the metal mesh 38 is fixed. As shown in FIG. 1, the connection between the hollow extruded concrete panels 30 in the left-right direction is such that the fitting concave portions 32 and the fitting convex portions 33 on the side surfaces of the adjacent hollow extruded concrete panels 30 are fitted and fixed. In the vertical connection, the end faces of the ferrite plate 1 facing the opening of the hollow portion 31 of the facing hollow extruded concrete panel 30 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 make it.

When the side wall of the building is actually formed of a radio wave absorbing wall for building material, the lower end of the hollow portion 31 of the hollow extruded concrete panel 30 at the lowermost end is used to secure the ferrite plate 1 securely. It is advisable to fill with concrete or the like (so that the ferrite plate does not slip down).

Here, the radio wave absorption characteristic (frequency characteristic of return loss) of the radio wave absorption wall for building material of the first embodiment obtained by the above configuration is shown in a curve (a) of FIG. (Thickness 10 mm, concrete thickness 14 mm in front of ferrite plate, air layer thickness 20 mm, concrete thickness behind 14 mm). Compared with the curve (b) in FIG. 18 which is the radio wave absorption characteristic of the conventional typical three-layer 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. It can be seen that the wall has excellent characteristics both in radio wave absorption and frequency characteristics.

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

(1) Hollow extruded concrete panel 3
0, the ferrite plate 1 is arranged so as to be continuous in the magnetic field direction of the arriving radio wave and the air layer 35 is located behind the radio wave arrival direction. Suppress the influence, ferrite plate 1
By lowering the effective dielectric constant between the antenna and the metal mesh 38 serving as a radio wave reflector, the deterioration of the radio wave absorption characteristics of the ferrite plate can be suppressed to a small extent, and the band of the radio wave absorption characteristics can be widened. Therefore, compared with the conventional structure in which the ferrite plate is surrounded by concrete, mortar, or the like, the radio wave absorption characteristics are greatly improved, and the VHF, UH
A radio wave absorption wall for building materials for ghost damage countermeasures exhibiting excellent radio wave absorption characteristics in the range of 100 MHz to 500 MHz where a so-called ghost problem in the F low channel is likely to occur is obtained.

The thickness 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 rear wall thickness of the hollow extruded concrete panel 30 so that the The effect of suppressing the effect 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 achieved. can do.

(2) The hollow extruded concrete panel 30 having the 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.
And has sufficient strength, so that it is not necessary to separately cast concrete for fixing the ferrite plate 1. Using such an inexpensive concrete panel, the hollow part 31 is aligned with the alignment guide of the ferrite plate 1 and the ferrite plate 1.
By using it as a fall prevention, the ferrite plate alignment process can be omitted, and the process 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 properties may be degraded due to, for example, a force being applied to the ferrite plate due to the shrinkage ratio during hardening of 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 the molding and hardening, there is no fear of deterioration in magnetic characteristics.

(4) Since the hollow portion 31 is provided with a pair of convex portions 34 for regulating the position of the ferrite plate, the ferrite plate 1 has the front surface 34a of the convex portion 34 and the inner surface 31a on the front side of the hollow portion 31 as shown in FIG. Can be positioned in the space on the front side of the hollow portion 31, and the ferrite plate 1 can be easily and reliably aligned and maintained in a state where the ferrite plate 1 is continuous in the magnetic field direction of the arriving radio wave. Therefore, at the time of concrete placing, which has been performed with the conventional structure, there is no need to perform an operation of fixing the ferrite plates 1 so as not to move, so that the manufacturing process can be simplified and the manufacturing is facilitated. Therefore, significant cost reduction can be achieved in combination with the effect of the above item (2).

The adhesive 37 used in the first embodiment was used.
Is a hollow extruded concrete panel 3
The ferrite 1 is held in a state where the position is regulated by the pair of convex portions 34 once the radio wave absorbing wall for building material is assembled as a side wall of the building. It is sufficient that the prevention of the fall of the ferrite plate 1 is surely performed.

FIGS. 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 molded concrete panel 30 and the ferrite plate 1 fixed inside the hollow portion 31 is slightly large, the ferrite plate 1 is continuously aligned in the magnetic field direction of the incoming radio wave without rattling. It has a possible configuration. That is, a pair of fixing members 50 are used for fitting and fixing the ferrite plate 1 to the hollow portion 31. The fixing member 50 is formed by molding an insulating inorganic material (an organic material can be used, but an inorganic material is preferable in consideration of fire resistance) so that the cross section becomes substantially L-shaped. In this case, the ferrite plate 1 is disposed in a front space defined by a 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 as shown in FIG.
And a pair of fixing members 50 are inserted so as to fill a gap between the ferrite plate 1 and the hollow portion 31. That is, the ferrite plate 1
Of the ferrite plate 1
The fixing member 50 is interposed between the front side corner of the hollow portion 31 and the front side corner of the hollow portion 31, and an adhesive 37 is provided in a gap between the hollow portion 31 and the front surface of the ferrite plate 1.

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

The rest of the configuration and the operation and effect are the same as those of the first embodiment, and the same or corresponding members are denoted by the same reference characters and description thereof will be omitted.

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

In each of the above-described embodiments, the hollow extruded concrete panel 30 is not provided with an exterior material. However, as the exterior material, paint, resin, mortar, or the like is provided on the front surface of the hollow extruded concrete panel 30 . Painting·
A spraying material may be added.

[0054] Although a metal mesh 38 as a radio wave reflector arranged behind the hollow extruded concrete panels 30 in each of the embodiments, or paste a metal sheet on the back of the hollow extruded concrete panels 30, conductive A configuration in which a paint is applied may be used.

In each embodiment, a metal mesh 38 as a radio wave reflector is fixed to a structural body 39 in advance.
Was when fixing the hollow extruded concrete panels 30 to the structural skeleton 39 configured to position the back of the hollow extruded concrete panels 30, before the concrete during extrusion of the hollow extruded concrete panels 30 is cured, the The metal mesh 39 may be pressed against the back surface of the hollow extruded concrete panel 30 to be integrated.

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

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. Would.

[0058]

As described above, according to the radio wave absorbing wall for a building material of the present invention, the ferrite is disposed in the hollow portion of the insulating hollow structure so that the air layer exists behind the ferrite plate as viewed from the radio wave arrival direction. Because the plates are arranged continuously in the direction of the magnetic field, the effective dielectric constant behind the ferrite plate is reduced, the deterioration of the radio wave absorption characteristics of the ferrite plate can be suppressed to a small extent, and the radio wave absorption characteristics can be improved. Broadband of the radio wave absorption characteristics can be achieved.

When a ferrite plate is provided, a hollow portion continuous in the direction of a magnetic field is formed at intervals in the direction of the electric field of an incoming radio wave.
Number of protrusions to regulate the position of the ferrite plate in each hollow part
The front space part is provided by looking at each hollow part from the direction of radio wave arrival.
And a rear space, and a ferrite plate in the front space.
It is only necessary to fit and arrange, so that the front space portion of each hollow portion can be used as an alignment guide for the ferrite plate, and also the fall of the ferrite plate can be prevented, thereby simplifying the manufacturing process. It is easy to manufacture.

Further, since the ferrite plate is arranged in the hollow portion of the insulating hollow structure, there is no possibility that the magnetic properties are degraded due to stress applied to the ferrite plate.

Accordingly, a radio wave absorbing wall for a building material which has sufficient strength as a wall material for a building material, realizes a necessary and sufficient broadband radio wave absorbing characteristic, and is suitable for countermeasures against ghost failures which is easy to manufacture and inexpensive is obtained.

[Brief description of the drawings]

FIG. 1 is a plan sectional view showing a first embodiment of a radio wave absorbing wall for building materials 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 the first embodiment.

FIG. 4 is a perspective view showing a hollow extruded 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 a partially enlarged plan sectional view of the same.

FIG. 8 is a plan view showing a first conventional example of a radio wave absorption wall in which a ferrite plate is arranged so as to be continuous in a magnetic field direction and discontinuous in an electric field direction.

FIG. 9 is a front view of the same.

FIG. 10 is a plan view showing a second conventional example of a radio wave absorbing wall in which a ferrite plate is arranged so as to be continuous in a magnetic field direction and discontinuous in an electric field direction.

FIG. 11 is a front view of the same.

FIG. 12 is a perspective view showing a third conventional example of a radio wave absorbing wall having a structure to be fixed with an exterior tile with special feet.

FIG. 13 is a plan sectional view of the same.

FIG. 14 is a graph showing a radio wave absorption characteristic in a basic configuration of a radio wave absorption wall.

FIG. 15 is a graph showing radio wave absorption characteristics when mortar is loaded on the basic configuration of the radio wave absorption wall.

FIG. 16 is a graph showing radio wave absorption characteristics of the first embodiment of the present invention and a third conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ferrite plate 2 Metal plate 30 Hollow extruded concrete panel 31 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 Connection metal fitting 50 Fixing member

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-241199 (JP, A) Japanese Utility Model Showa 55-25375 (JP, U) Japanese Utility Model Utility Model Showa 55-40574 (JP, U) (58) Field (Int.Cl. ⁶ , DB name) H05K 9/00

Claims (2)

(57) [Claims] The method according to claim 1 hollow portion continuous in the direction of the magnetic field of the incoming radio wave
Regulate the position of the ferrite plate in each hollow part of the insulating hollow structure provided at intervals in the direction of the electric field of the incoming radio wave
Protrusions are provided, and each hollow part is viewed from the direction of arrival of radio waves.
Part was divided into a rear-side space and a fitting arrangement <br/> in the front space by continuously to the magnetic field direction as there is an air layer behind the ferrite plate the ferrite plate as viewed from the DOA A radio wave absorbing wall for a building material, wherein a radio wave reflector is disposed behind the insulating hollow structure. 2. The radio wave absorbing wall according to claim 1 , wherein the air layer has a thickness greater than a thickness of the ferrite plate.