JP2000240189A - Radio wave absorbing precast concrete plate and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lightweight radio wave absorbing PC plate which can be inexpensively manufactured as an external facing material of a building and is capable of preventing radio wave interference due to reflection at a building by efficiently absorbing electromagnetic waves such as television radio waves and to provide its manufacturing method. SOLUTION: This radio wave absorbing PC plate 1 is constituted of a crosspiece-type radio wave absorbing body 2 and a base concrete 3 to hold a crosspiece-type radio wave absorbing body unit 20 formed of a mortar layer 5 of the same width with the crosspiece-type radio wave absorbing body 2 provided on the front surface of the crosspiece-type radio wave absorbing body 2 and fixing anchors 6 planted in the mortar layer 5 to pass through between crosspiece-type ferrite magnetic bodies 11 and a radio wave reflecting plate 12 as an integrated crosspiece-type radio wave absorbing body so as to absorb electromagnetic waves efficiently to prevent radio wave interference due to reflection at a building. In its manufacture, the previously manufactured crosspiece-type radio wave absorbing body unit 20 is arranged opposite to a radio wave reflecting plate and set in a mold with the mortar layer 5 on the lower side, and base concrete is placed in the mold.

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 precast concrete plate which uses a cross-shaped ferrite magnetic material to prevent reflection interference of television radio waves and the like, and a method of manufacturing the same.

[0002]

2. Description of the Related Art When a situation is established in which a building blocks an electromagnetic wave flying around the building, the electromagnetic wave reflects on the building and generates secondary noise around the building, thereby causing a new electromagnetic wave disturbance. . At present, television waves exist as electromagnetic waves constantly flying around buildings, and V
The frequency used for both HF and UHF television waves is 90-7
A wide frequency band of 70 MHz is formed. And
When a high-rise building is constructed, the television wave reflected from the building has its influence over a long distance, and has caused radio interference such as ghosts in a wide area.

For this reason, with respect to the reflection obstruction and the obstruction obstruction of the television wave, countermeasures against the trouble of the television wave have been studied in high-rise buildings. Among the obstacles of television radio waves, various kinds of measures have conventionally been taken for reflection obstacles because the affected area is far and wide. As a measure to absorb radio waves without reflecting them, considering the industrialization of construction, precast concrete (hereinafter referred to as “P
C) (abbreviated as "C") on the outer wall surface of the building to provide the building with electromagnetic wave absorbing performance.

As shown in FIG. 8A, for example, a conventional radio wave absorbing PC board 30 has tiles 32 arranged on a bottom surface 31a of a mold frame 31, and a ferrite plate 33
Is directly set, the reinforcing steel bars 34 are arranged in a lattice shape in a plan view, and then concrete 35 is poured into the formwork 31 to manufacture. At this time, a ridge 32 for securely attaching the tile 32 to the concrete 35 is provided on the back surface of the tile 32.
a and 32a. In a similar manner, FIG.
As shown in (b), the anchor 3 is attached to the back of the tile 32 '.
6 may be provided.

As another method, as shown in FIG.
After arranging the flat tiles 37 on the bottom surface 31a of the mold frame 31, a mortar 38 is cast on the upper surface thereof,
After the ferrite plate 33 and the fixed anchor 39 are partially buried and set on the upper surface of 8, the reinforcing bars 34 and the concrete 35 are sometimes placed. In any of the above examples, the ferrite magnetic material is arranged corresponding to the back surface of the tile, and the protrusions and anchors for adhering and fixing to the concrete are arranged on both sides of the ferrite. For this reason, the ferrite disposed on the front surface of the reflective reinforcing bar has to be attached leaving a gap that cannot be set continuously and cannot be reduced.

[0006]

For this reason, in addition to the narrow frequency band of the electromagnetic wave absorbed by the ferrite tile itself, because of the absorption efficiency of the reflected electromagnetic wave generated from the above-described structure, the ferrite tile is not suitable for VHF. For UHF and UHF, different sizes and arrangements have to be prepared and corresponded. As a result, in order to absorb electromagnetic waves over a wide frequency band in response to VHF and UHF of television radio waves, the weight of the radio wave absorption PC board and the complexity of selection have become problems. Then, VHF of the television wave,
A single radio wave absorption PC that can support all UHF frequency bands
A plate is desired, and furthermore, not only for specific electromagnetic waves such as horizontally polarized television waves, but also for all electromagnetic waves irrespective of horizontal and vertical through artificial satellites Improvements are expected.

[0007] The above-described conventional method of manufacturing a radio wave absorbing PC board has the following problems. That is, FIG.
In the method using the tile 32 shown in FIG.
Since the ridge 32a must be formed on the back surface of 2,
The production cost of the tile 32 increases, and this is
There is a problem that the cost of the C plate is increased. FIG.
In the method using the tile 32 'shown in FIG. 3B, the anchor 36 is provided on the back surface of the tile 32'. However, in order to fix the anchor 36 to the tile 32 ', processing such as making a hole in the back surface is necessary. Therefore, also in this case, the manufacturing cost is high. Moreover, when the tiles 32 'are thin, it is difficult to fix the anchor 36.

Further, in the method shown in FIG. 9, since the flat tiles 37 are used, the above problem can be avoided. However, since the mortar 38 and the concrete 35 are double-layered, it takes much time and effort. There is a problem that the property becomes worse. In addition, the electromagnetic wave absorption performance of the ferrite plate 3
Since it is affected by the water content of the mortar 38 present on the front surface of the mortar 3, it takes time and effort to dry the mortar 38, which also lowers the productivity.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problem awareness, and by arranging a ferrite plate as a radio wave absorbing PC plate integrally and continuously, electromagnetic waves such as television radio waves can be obtained. The present invention provides a radio wave absorbing PC board which can be efficiently manufactured to prevent radio interference caused by reflection of a building, and can be manufactured as a lightweight and inexpensive exterior material for a building, and a method of manufacturing the same.

[0010]

The radio wave absorbing PC board according to the first aspect of the present invention is implanted in a cross-shaped radio wave absorber, a mortar layer of the same width provided on the front surface of the cross-shaped radio wave absorber, and a mortar layer. A beam-shaped radio wave absorber unit consisting of a fixed anchor penetrating between the beam-shaped ferrite magnetic material of the beam-shaped radio wave absorber and the radio wave reflector, and a plurality of beam-shaped radio wave absorber units are held as an integrated beam-shaped radio wave absorber. It is composed of base concrete and efficiently absorbs electromagnetic waves to prevent radio interference due to building reflections.

A radio wave absorbing PC board according to the invention of claim 2 is
2. The radio wave absorbing PC board according to claim 1, wherein the cross-shaped electromagnetic wave absorber is formed by arranging a cross-shaped ferrite magnetic body on a radio-wave reflecting plate having a predetermined width, and the length of the cross-shaped ferrite magnetic body is measured by a radio wave. The height, thickness, and spacing of the ferrite magnetic body are specified in relation to the wavelength of radio waves, the angle of incidence, and the mortar layer on the front of the ferrite magnetic body. In addition to the above-mentioned functions, it is possible to efficiently absorb broadband electromagnetic waves to prevent radio interference caused by the reflection of a building, and to manufacture a lightweight and inexpensive device.

According to a third aspect of the present invention, there is provided a radio wave absorbing PC board.
The radio wave absorbing PC board according to claim 1 or 2, wherein the cross-shaped ferrite magnetic material is arranged in parallel on the radio wave reflecting plate, and the function is further improved by coping with electromagnetic waves in a predetermined direction. ing.

According to a fourth aspect of the present invention, there is provided a radio wave absorbing PC board.
3. The radio wave absorbing PC board according to claim 1, wherein the cross-shaped ferrite magnetic material is arranged in a grid on the radio wave reflecting plate, and the above function is improved by coping with electromagnetic waves in all directions. ing.

According to a fifth aspect of the present invention, there is provided a radio wave absorbing PC board.
The radio wave absorbing PC board according to any one of claims 1 to 4, wherein the radio wave reflecting plate of the wave-shaped radio wave absorber unit faces the radio wave reflecting plate of an adjacent wave-shaped radio wave absorber unit, and the end of the radio wave reflecting plate. The spacing between the bar-shaped ferrite magnetic bodies arranged in the section is the same as the spacing between the bar-shaped ferrite magnetic bodies in the bar-shaped radio wave absorber unit, and a plurality of bar-shaped radio wave absorber units are integrated into a It functions effectively as an absorber.

According to a sixth aspect of the present invention, there is provided a method of manufacturing a radio wave absorbing PC board according to any one of the first to fifth aspects.
A method of manufacturing a C-plate, comprising: a cross-shaped radio wave absorber; a mortar layer having the same width provided on a front surface of the cross-shaped radio wave absorber; A beam-shaped radio wave absorber unit consisting of a fixed anchor penetrating through the radio wave reflector and a beam-shaped radio wave absorber is prepared in advance, and the mortar layer is set downward so that the radio wave reflectors of the beam-shaped radio wave absorber face each other. After setting the absorber unit in the formwork, the fixed anchor is tightened to the concrete rebar, and then base concrete is poured into the formwork,
It secures radio wave absorption performance and quality and improves productivity.

According to a seventh aspect of the present invention, there is provided a cross-shaped radio wave absorber unit for use in the method of manufacturing a radio wave absorbing PC board according to the sixth aspect. A mortar layer of the same width provided on the front of the type electromagnetic wave absorber and a fixed anchor that is implanted in the mortar layer and between the bar-shaped ferrite magnetic bodies of the beam-shaped electromagnetic wave absorber and penetrates the radio wave reflector. Productivity is improved by the stability of absorption performance and the simplicity of handling.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION A radio wave absorbing PC board according to the present invention
Basically, a cross-shaped radio wave absorber, a mortar layer of the same width provided in front of the cross-shaped radio wave absorber, and penetrated between the cross-shaped ferrite magnetic material of the cross-shaped radio wave absorber and the radio wave reflector. It consists of a cross-shaped radio wave absorber unit consisting of fixed anchors and a foundation concrete that holds a plurality of cross-shaped radio wave absorber units as an integrated cross-shaped radio wave absorber. Radio interference due to reflection is prevented. Hereinafter, the radio wave absorbing PC according to the present invention
An embodiment of a plate will be described with reference to the drawings.

FIG. 1 is a perspective view of a radio wave absorbing PC board according to the present invention. The radio wave absorption PC board 1 integrally includes a cross-shaped radio wave absorber 2 and a plurality of cross-shaped radio wave absorber units 20 including a mortar layer 5 having the same width and a fixed anchor 6 provided on the front surface of the cross-shaped radio wave absorber 2. It is composed of a base concrete 3 held as a cross-shaped radio wave absorber and a radio wave absorption PC
The mortar layer 5, which forms the surface of the board 1, is embedded in the base concrete 3 except for the front surface 4. The cross-shaped electromagnetic wave absorber 2 and the mortar layer 5 are joined to each other on the surface side of the cross-shaped ferrite magnetic body, and are fixed by an elastic adhesive (not shown) or the like. Furthermore, the fixed anchor 6 is implanted in the crosspiece type radio wave absorber unit 20. One end of the fixed anchor 6 is implanted in the mortar layer 5, penetrates between the bar-shaped ferrite magnetic material and the radio wave reflector, and the other end is embedded in the base concrete 3. Numeral 20 is firmly connected to the base concrete 3,
The C plate has a sufficient strength. The mortar layer 5
It is also possible to attach a tile, a stone, or the like to the front surface 4 or apply a spraying material to the front surface 4 so as to form a surface finishing material of the radio wave absorbing PC board 1.

FIG. 2 is a perspective view of a cross-shaped radio wave absorber unit constituting the radio wave absorbing PC board according to the present invention.
FIG. 4 is an elevational sectional view of a cross-shaped radio wave absorber unit. As shown in FIG. 2 and FIG. 3, the cross-shaped radio wave absorber unit 20
A mortar layer 5 forming the surface of the radio wave absorbing PC board, and a band-shaped radio wave absorber 2 extending in one direction by joining a ferrite surface of a cross-shaped ferrite magnetic material to the mortar layer 5 are arranged at predetermined intervals. The front surface 4 of the mortar layer 5 forms the surface of the radio wave absorbing PC board 1.

The mortar layer 5 is formed to have the same width and a predetermined thickness as the cross-shaped radio wave absorber 2, and reinforcing bars 7 are embedded on both sides thereof so that the mortar layer does not warp in the longitudinal direction. It is suppressed as follows. In the mortar layer 5, a fixed anchor 6 is implanted so as to penetrate a radio wave reflecting plate 12 of a cross-shaped electromagnetic wave absorber 2 to be described later and pass between the cross-shaped ferrite magnetic bodies 11 arranged therein. The mortar layer 5 is made of, for example, fiber reinforced mortar, glass fiber mortar, vinylon fiber mortar, aramid fiber mortar, or the like, and functions as a reinforcing material for the cross-shaped electromagnetic wave absorber unit 20 that is long in one direction. .

The cross-shaped electromagnetic wave absorber 2 and the mortar layer 5 are joined to each other on the surface side of the cross-shaped ferrite magnetic material.
It is fixed by an elastic adhesive (not shown) or the like. The mortar layer 5 maintains the performance of the cross-shaped electromagnetic wave absorber 2 by reducing the water content by sufficient drying to make the electromagnetic characteristics as close to air as possible.

The fixed anchors 6 are arranged at predetermined intervals on both sides of the cross-shaped radio wave absorber unit 20 along the longitudinal direction. As shown in FIG. 3, each fixed anchor 6 in the present embodiment adopts a key-like shape with its tip bent outside the cross-shaped radio wave absorber unit 20. The fixed anchor 6 is used for tightening the reinforcing bars of the base concrete 3 with a wire or the like when the cross-shaped radio wave absorber units 20 are arranged in parallel and integrated by the base concrete 3, and at the same time, the fixed anchor 6 is connected to the base concrete 3. Power is increasing. Therefore, the tip shape of the fixed anchor 6 is
Various forms can be adopted as long as the above objects can be achieved. Further, when the fixing anchor 6 is required to function as a reinforcing material for the beam-shaped radio wave absorber unit 20 which is long in one direction, a plurality of joints are provided along the longitudinal direction of the beam-shaped radio wave absorber unit 20 although not shown. It is also possible to cope by joining the muscles to the fixed anchor and integrating them.

FIG. 4 shows an embodiment of the fixed anchor. The fixed anchor 8 shown in FIG. 4 (a) has a mortar layer 5 embedded with a fixing fitting 8-1 having a female screw formed therein. -2 is screwed. FIG. 4 (b)
The fixed anchor 9 shown in FIG. 1 has an enlarged portion 9-1 protruding from the tip portion embedded in the mortar layer 5 to enhance the adhesive force. The fixed anchor 10 shown in FIG. 4C has a plate 14 attached to a tip portion embedded in the mortar layer 5 with a nut 15.
The plate 14 expands its surface area to enhance adhesion to the mortar layer. In each of the above embodiments, the adhesive force between the fixed anchor and the mortar layer 5 is enhanced, but the tip of the fixed anchor buried in the base concrete 3 is also shown in FIG.
By adopting a shape similar to that shown in (b) or FIG. 4 (c), it is possible to enhance the bonding force between the crosspiece-shaped radio wave absorber unit 20 and the foundation concrete 3.

FIGS. 5A and 5B are a partial elevational view and a partial view for explaining the function of the radio wave absorbing PC board according to the present invention. As described above, the cross-shaped radio wave absorber unit 20 constituting the radio wave absorption PC board 1
It is composed of a mortar layer 5 forming the surface of the C-plate, a strip-shaped radio wave absorber 2 extending in one direction, and a fixed anchor 6.

As shown in the figure, the cross-shaped radio wave absorber 2 is configured by joining a rectangular parallelepiped cross-shaped ferrite magnetic body 11 on a radio-wave reflecting plate 12 which is a conductive metal body. The mortar layer 5 is formed to have the same width as the cross-shaped radio wave absorber 2, and the surface of the cross-shaped ferrite magnetic body 11 opposite to the cross-shaped radio wave absorber 2 and the radio wave reflection plate 12 is bonded with elasticity. By being fixed to each other using a material or the like, they are integrally connected.

In order to maintain the space between the bar-shaped ferrite magnetic bodies 11, the gap filling material 13
1 between them. In the present embodiment, joints made of commercially available polystyrene or foam are employed. However, as described later, it is desirable that the gap between the cross-shaped ferrite magnetic bodies be in a gap state. It is appropriate that the material has low water content and electromagnetic characteristics close to that of air. Therefore, when the cross-shaped ferrite magnetic body 11 can employ a fixing means that can withstand the strength without providing the gap filler 13, it is characteristically advantageous not to provide the gap filler 13. Therefore, it is desirable to omit the gap filler 13 to form an air layer.

The cross-shaped ferrite magnetic bodies 11 are ferrite magnetic bodies having a thickness t, a height h, and a length L, and are arranged in parallel at intervals s so that the longitudinal directions are the same. In order to absorb radio waves, the direction of the electric field of the incident radio waves is arranged so as to be orthogonal to the longitudinal direction of the bar-shaped ferrite magnetic body 11, and the magnetic field direction of the radio waves coincides with the longitudinal direction of the bar-shaped ferrite magnetic body. Should be arranged as follows. Therefore, in the case shown in the figure, it corresponds to the horizontal polarization of the TV radio wave.
This can be dealt with by arranging intersecting cross-shaped ferrite magnetic bodies in a grid pattern.

The above structure of the cross-shaped radio wave absorber 2 is based on a broadband ferrite radio wave absorber (see JP-A-4-42999).
Similarly to the above, a radio wave is converted into a TM wave and absorbed without being absorbed as it is as a TEM wave. When the above configuration is used as a transmission line model and the input impedance and the characteristic impedance of the transmission line are converted into an equivalent circuit, When a desired relationship is established between the input impedance of the ferrite magnetic material, the wavelength λ of the operating frequency of the operating radio wave, and the characteristic impedance, a state of zero reflection exists.

The input impedance of the bar-shaped ferrite magnetic body 11 is determined by the material such as the magnetic permeability and the dielectric constant of the bar-shaped ferrite magnetic body, the shape regulated by the thickness t, the height h, and the length L, and the spacing s. By adjusting the input impedance of the cross-shaped ferrite magnetic material, the state of zero reflection can be set. The interrelationship between the thickness t, height h, and length L of the cross-shaped ferrite magnetic material and the gap s to be arranged is selected as follows.

Considering the state of the operating radio wave, since the bar-shaped ferrite magnetic material has a magnetic field focusing action, if the bar-shaped ferrite magnetic material is continuous in the direction of the magnetic field component of the operating radio wave, the direction of the electric field is increased. Since the gap is hardly a problem, it is based on a thickness t that does not deteriorate the magnetic field absorption characteristics.

The height h is the thickness t of the crosspiece ferrite magnetic material.
It has been found that, when the gap and the gap s are kept constant, the characteristics in the high frequency range can be improved at the boundary of a predetermined value at the expense of the characteristics in the low frequency range. Therefore, in consideration of this characteristic, adjustment is made in accordance with the target frequency range within the range of the crosspiece-shaped ferrite magnetic body length L specifying the rectangular parallelepiped. Since it has been found that the gap s has an optimum value of t / s, it is effective to adjust the gap s within the range of the wavelength λ of the incident radio wave which affects the gap. That is, the shape and the arrangement of the cross-shaped ferrite magnetic body 11 are defined as L ≧ h ≧
By configuring the relationship of t and λ ≧ s ≧ t, it is possible to adjust so as to absorb radio waves incident in a wide frequency band and attenuate reflected radio waves to a predetermined level or less.

In the case of television waves, the frequency band is 90 to 770 MHz when covering the entire range of VHF and UHF. Therefore, it is necessary to absorb frequencies in these bands so as not to reflect them. According to an experiment, when the attenuation rate due to the absorption of the television wave is set to 15 to 25 dB, the width t of the ferrite magnetic material is 5 to 2 mm, and the height h is 16 to 22 m.
When the distance is set in the range of s = 15 to 40 mm while being adjusted to m, it is possible to deal with the light without substantially reflecting the light. However, the shape and arrangement interval of the cross-shaped ferrite magnetic material are determined in relation to the frequency of the radio wave, the incident angle, and the electromagnetic characteristics of the nearby structural materials, and the structural viewpoint and design It is necessary to appropriately select from the above viewpoints.

The cross-shaped radio wave absorber unit 2 and the mortar layer 5 of the present invention constitute the cross-shaped radio wave absorber unit 20 with the same width. The integration of the radio wave absorption function is attempted between the two. For this reason, in the present embodiment, the width between the end portions of the radio wave reflection plate 12 is set such that the width of the cross-shaped ferrite magnetic body 11 is
Is added to the value arranged in the above by (s−t) / 2 from the outside of the bar-shaped ferrite magnetic body 11 located at both ends. Since the width of the radio wave reflection plate 12 and the width of the mortar layer 5 are the same, when the cross-shaped radio wave absorber units 20 are adjacent to each other, the radio wave reflection plates 12
Are opposed to each other in a contact state, and the space between the bar-shaped ferrite magnetic bodies 11 located at both ends is ensured in the same manner as the other space S. Accordingly, the radio wave absorbing PC according to the present invention
Even when a plurality of cross-shaped radio wave absorber units are juxtaposed, the plate exhibits integrated performance in terms of the radio wave absorption function.

Further, this matching relationship is determined by the radio wave reflecting plate 12.
This can also be achieved by disposing the cross-shaped ferrite magnetic body 11 in a state of being shifted to one end of the radio wave reflection plate 12 with respect to the above. That is, the cross-shaped ferrite magnetic body 11 is arranged so as to coincide with one end of the radio wave reflection plate 12, and the other end of the radio wave reflection plate 12 is (st−st) from the outside of the cross-shaped ferrite magnetic body 11 located at the end. This is because the space between the bar-shaped ferrite magnetic bodies 11 located at both ends can be similarly secured by arranging them in the extended state.

As described above, the radio wave absorbing PC according to the present invention
The plate is pierced between the cross-shaped ferrite magnetic body of the cross-shaped radio wave absorber, the mortar layer having the same width provided on the front surface of the cross-shaped radio wave absorber and the mortar layer, and penetrates the radio wave reflecting plate. Since it is composed of a cross-shaped radio wave absorber unit consisting of fixed anchors and base concrete that holds a plurality of cross-shaped radio wave absorber units as an integrated cross-shaped radio wave absorber, horizontal polarization and vertical In addition to absorbing and attenuating polarized electromagnetic waves over a wide band, the use of ferrite magnetic materials and reflective rebar is reduced, manufacturing costs are improved, and at the same time, the overall weight is reduced to make handling easier and easier. Solving the problem.

Next, a method of manufacturing a radio wave absorbing PC board according to the present invention will be described. The method for manufacturing a radio wave absorbing PC board according to the present invention includes a cross-shaped radio wave absorber 2, a mortar layer 5 having the same width provided on the front surface of the cross-shaped radio wave absorber, and a cross-shaped A beam-shaped radio wave absorber unit 20 composed of a fixed anchor penetrating between the ferrite magnetic bodies 11 and the radio wave reflection plate 12 is manufactured in advance, and the mortar is set so that the radio wave reflection plates 12 of the beam-shaped radio wave absorber 2 face each other. With the layer 5 on the lower side, the cross-shaped radio wave absorber unit is
6, the fixed anchor 6 is tightened to the concrete reinforcing bar, and then the base concrete 3 is set in the formwork.
To ensure radio wave absorption performance and quality and improve productivity. Hereinafter, an embodiment of a method of manufacturing a radio wave absorbing PC board according to the present invention will be described with reference to the drawings.

The method of manufacturing a radio wave absorbing PC board according to the present invention is similar to the cross-shaped radio wave absorber unit 2 described with reference to FIGS.
0 is manufactured in advance for a predetermined number of sheets. Prefabricated beam-type radio wave absorber unit 20
Since the mortar layer 5 forming the surface of the radio wave absorbing PC board has the same width as the cross-shaped radio wave absorber 2 and is integrated with the fixed anchor 6, the mortar layer 5 has a special shape. There is no need to perform special processing, and the plate can be simply formed into a flat plate, so that the manufacturing cost can be reduced.

Further, by manufacturing the beam-type electromagnetic wave absorber unit 20 in advance, it is possible to surely dry the mortar layer 5 which is in a water-containing state at the time of manufacture from the side of the reflector of the beam-type electromagnetic wave absorber 2. Therefore, it is possible to improve and stabilize the radio wave absorption performance.

Further, the cross-shaped radio wave absorber unit 20
Since the mortar layer 5 is formed from fiber reinforced mortar, glass fiber mortar, vinylon fiber mortar, aramid fiber mortar, etc., and reinforcing steel bars 7 are embedded on both sides thereof,
In combination with the integrated structure with the cross-shaped radio wave absorber 2, the strength of the cross-shaped radio wave absorber unit 20 which is long in one direction can be ensured, and the cross-shaped radio wave absorber unit 2 can be dried.
It is ensured that zero warpage is prevented.

6 and 7 show the steps of manufacturing the radio wave absorbing PC board according to the present invention. The manufacture of the radio wave absorbing PC board according to the present invention includes the steps of:
The process is started by setting 0,... On the bottom surface 16a of the formwork 16, which is assembled into a predetermined size as shown in FIG. Each beam type radio wave absorber unit 20
The front surface 4 of the mortar layer 5 forming the surface of the radio wave absorbing PC plate faces downward, and the adjacent radio wave reflecting plates 12 face each other and come into contact with each other. It is arranged at a predetermined gap and set so as to function as an integral cross-shaped radio wave absorber. In addition, a joint material 17 such as a sponge is arranged between the beam-shaped radio wave absorber units 20 adjacent to each other so as to form a necessary joint without damaging the radio wave absorption performance.

Then, as shown in FIG. 7, after the setting of the beam-shaped radio wave absorber unit 20 is completed, a desired reinforcing reinforcing bar 18 is arranged at a predetermined position above it. Thereafter, the form 16
Concrete 19 is poured into the inside to a predetermined level. Then, after the concrete 19 hardens and develops a predetermined strength, the concrete 19 is removed from the mold 16 and the joint material 17 is removed. By this, the surface is formed by the front surfaces 4, 4,... Of the mortar layer, and each cross-shaped radio wave absorber unit is formed as one radio wave absorbing PC board 1 by concrete 19.
The radio wave absorbing PC board 1 in which the cross-shaped radio wave absorbers 2, 2,...
The concrete 19 includes ordinary concrete,
Various materials such as lightweight concrete and fiber reinforced concrete can be used.

As described above, the radio wave absorbing PC according to the present invention
The method of manufacturing the plate is based on the use of the beam-shaped radio wave absorber unit 20 having the surface in front of the mortar layer, as compared with the conventional case where tiles or the like are directly set as panel materials in a formwork as in the related art. In addition, the labor for setting tiles and the like can be greatly reduced, and the productivity can be improved.

Further, unlike the conventional method, the mortar and the concrete are not driven twice, and only the concrete 19 is poured into the formwork 16 once. Can be achieved.

The radio wave absorption P described in the above embodiment
In the method of manufacturing the C plate, the configuration of the front surface 4 of the mortar layer and the shape of the reinforcing bar 6 forming the surface of the radio wave absorbing PC plate is not limited at all. It is also possible to attach a plurality of rows of cross-shaped radio wave absorbers to the cross-shaped radio wave absorber unit 20.

As described above, the present invention has been described in detail based on the embodiments. However, the present invention is not limited to the above embodiments, and various modifications may be made without departing from the spirit of the present invention. Of course, it is possible.

[0046]

The radio wave absorption P according to the first aspect of the present invention.
The C-plate is embedded in the mortar layer and the mortar layer of the same width provided on the front surface of the cross-shaped radio wave absorber, the cross-shaped radio wave absorber, and penetrates between the cross-shaped ferrite magnetic material of the cross-shaped radio wave absorber and the radio wave reflector. The electromagnetic wave absorber unit consists of a fixed anchor that is made up of fixed anchors, and the base concrete that holds multiple beam-shaped electromagnetic wave absorber units as an integrated wave-shaped electromagnetic wave absorber, absorbing and attenuating electromagnetic waves over a wide band. At the same time, the manufacturing cost is improved, and at the same time, the overall weight is reduced, thereby facilitating the handling and preventing the radio interference caused by the reflection of the building.

The radio wave absorbing PC according to the second aspect of the present invention.
The plate is the radio wave absorbing PC board according to claim 1, wherein the cross-shaped radio wave absorber is formed by arranging a cross-shaped ferrite magnetic body on a radio wave reflecting plate having a predetermined width, and a length of the cross-shaped ferrite magnetic body. The direction is arranged almost parallel to the direction of the magnetic field of the radio wave, and the height, thickness and spacing of the cross-shaped ferrite magnetic material are determined in relation to the wavelength of the radio wave, the incident angle and the mortar layer on the front of the ferrite magnetic material. Since it is characterized by being set to a predetermined value, in addition to the above effects, it efficiently absorbs broadband electromagnetic waves and prevents radio interference due to building reflection,
It has the effect of being lightweight and inexpensive to manufacture.

The radio wave absorbing PC according to the third aspect of the present invention.
The plate is characterized in that, in the radio wave absorbing PC plate according to claim 1 or 2, the cross-shaped ferrite magnetic material is arranged in parallel on the radio wave reflecting plate, so that the above effect can be obtained by coping with electromagnetic waves in a predetermined direction. The effect of further improving is exhibited.

The radio wave absorbing PC board according to the fourth aspect of the present invention
The radio wave absorbing PC board according to claim 1 or 2, wherein the cross-shaped ferrite magnetic material is arranged in a grid on the radio wave reflecting plate, so that the above effect can be further improved by coping with electromagnetic waves in all directions. It has the effect of improving.

The radio wave absorbing PC according to the fifth aspect of the present invention.
The plate is a radio wave absorbing PC according to any one of claims 1 to 4.
In the board, the radio wave reflection plate of the cross-shaped radio wave absorber unit,
The gap between the bar-shaped ferrite magnetic bodies arranged at the end of the radio wave reflector is set to the distance between the bar-shaped ferrite magnetic bodies in the bar-shaped radio wave absorber unit. Since the interval is the same, in addition to the above-described effects, an effect of effectively functioning a plurality of cross-shaped radio wave absorber units as an integrated cross-shaped radio wave absorber is exhibited. .

A radio wave absorbing PC according to the invention of claim 6
The method for producing a plate is a method for producing a radio wave absorbing PC board according to any one of claims 1 to 5, wherein
A mortar layer of the same width provided on the front surface of the ridge-shaped electromagnetic wave absorber and a fixed-wave anchor composed of fixed anchors that are implanted in the mortar layer between the ferrite magnetic material of the ridge-shaped electromagnetic wave absorber and penetrate the radio wave reflector. The unit is manufactured in advance and the mortar layer is set down so that the radio wave absorber unit is set in the mold so that the radio wave reflectors of the radio wave absorber face each other. Since the base concrete is fastened to the rebar and the base concrete is poured into the formwork after that, the effect of securing radio wave absorption performance and quality and improving productivity is exhibited.

According to a seventh aspect of the present invention, there is provided a cross-shaped radio wave absorber unit for use in the method of manufacturing a radio wave absorbing PC board according to the sixth aspect, wherein the cross-shaped radio wave absorber is provided. And a fixed mortar layer provided on the front surface of the cross-shaped radio wave absorber and fixed anchors that are implanted in the mortar layer and between the cross-shaped ferrite magnetic bodies of the cross-shaped radio wave absorber and penetrate the radio wave reflector. Therefore, the stability of radio wave absorption performance and the simplicity of handling are effective in improving productivity.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a radio wave absorbing PC board according to the present invention.

FIG. 2 is a perspective view showing a cross-shaped radio wave absorber unit constituting the radio wave absorbing PC board;

FIG. 3 is an elevational sectional view of a cross-shaped radio wave absorber unit constituting the radio wave absorbing PC board;

FIG. 4 is a view showing an embodiment of a fixed anchor implanted in the crosspiece electromagnetic wave absorber unit.

FIG. 5 is a partial elevation view and an arrow view illustrating the function of the radio wave absorbing PC board according to the present invention.

FIG. 6 is a sectional elevational view showing a state in which a cross-shaped radio wave absorber unit is arranged in a mold in a method of manufacturing a radio wave absorbing PC board according to the present invention.

FIG. 7 is a sectional elevational view showing a state where concrete is poured into a formwork in the method of manufacturing a radio wave absorbing PC board according to the present invention.

FIG. 8 is an elevational sectional view showing a conventional method of manufacturing a radio wave absorbing PC board.

FIG. 9 is an elevational sectional view showing another example of a conventional method of manufacturing a radio wave absorbing PC board.

[Explanation of symbols]

1 radio wave absorption PC board, 2 cross type radio wave absorber unit,
3 foundation concrete, 4 front of mortar layer, 5
Mortar layer, 6 fixed anchors, 7 reinforcing bars,
8, 9, 10 Fixed anchor, 11 Cross-shaped ferrite magnetic material, 12 Radio wave reflector, 13 Void filler, 14
Plate, 15 nut, 16 formwork, 16a
Bottom, 17 joints, 18 reinforced steel, 19 concrete, 20 beam-type radio wave absorber unit, 30 radio wave absorption PC board, 31 formwork, 31a formwork bottom,
32, 37 tiles, 33 ferrite plate, 34
Reflective steel, 35 concrete, 36 anchor,
38 mortar, 39 fixed anchor,

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tadahiko Suzuki 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Construction Co., Ltd. (72) Inventor Masatake Kumo 1-2-3 Shibaura, Minato-ku, Tokyo Shimizu Construction Co., Ltd. (72) Inventor Koji Nagata 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Corporation (72) Inventor Shigeo Numata 1-2-3 Shibaura, Minato-ku, Tokyo Shimizu Corporation (72) Inventor Toshihiro Yamane 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Corporation (72) Inventor Yutaka Kimura 2-3-1-3 Kiba, Koto-ku, Tokyo Inside SPC Precon Co., Ltd.

Claims (7)

[Claims] 1. A cross-shaped radio wave absorber, a mortar layer of the same width provided on the front surface of the cross-shaped radio wave absorber, and a radio wave reflection between a cross-shaped ferrite magnetic material of the cross-shaped radio wave absorber and implanted in the mortar layer. A radio-wave absorbing precast concrete plate comprising a cross-shaped radio wave absorber unit comprising a fixed anchor penetrating the plate and a base concrete holding a plurality of cross-shaped radio wave absorber units as an integrated cross-shaped radio wave absorber. 2. A cross-shaped electromagnetic wave absorber, wherein a cross-shaped ferrite magnetic body is disposed on a radio-wave reflector having a predetermined width, and a length direction of the cross-shaped ferrite magnetic body is substantially parallel to a magnetic field direction of the radio wave. The height, thickness and spacing of the cross-shaped ferrite magnetic material are set to predetermined values in relation to the wavelength of the radio wave, the incident angle, the mortar layer on the front surface of the ferrite magnetic material, and the like. The radio wave absorbing precast concrete plate according to claim 1, wherein: 3. The radio wave absorbing precast concrete plate according to claim 1, wherein the bar-shaped ferrite magnetic material is arranged in parallel on the radio wave reflecting plate. 4. The crosspiece-shaped ferrite magnetic material is arranged in a grid on a radio wave reflection plate.
The radio wave absorbing precast concrete plate described in 1. 5. A beam-shaped ferrite magnetic material disposed at an end of a radio wave reflecting plate of an adjacent wave-shaped radio wave absorber unit such that the radio wave reflecting plate of the wave-shaped radio wave absorbing unit faces the radio wave reflecting plate of an adjacent wave-shaped radio wave absorbing unit. The radio wave absorbing precast concrete plate according to any one of claims 1 to 4, wherein an interval between the precast concrete plates is equal to an interval between the cross-shaped ferrite magnetic bodies in the cross-shaped electromagnetic wave absorber unit. 6. A cross-shaped radio wave absorber, a mortar layer of the same width provided on the front surface of the cross-shaped radio wave absorber, and a radio wave reflection between the cross-shaped ferrite magnetic material implanted in the mortar layer and the cross-shaped radio wave absorber. A beam-type radio wave absorber unit composed of fixed anchors penetrating the plate is manufactured in advance, and the beam-type radio wave absorber unit is placed with the mortar layer down so that the radio wave reflectors of the beam type radio wave absorber face each other. The radio-wave absorbing precast according to any one of claims 1 to 5, wherein the fixed anchor is fastened to the concrete reinforcing bar after setting in the formwork, and then base concrete is poured into the formwork. Manufacturing method of concrete board. 7. A cross-shaped radio wave absorber, a mortar layer of the same width provided on the front surface of the cross-shaped radio wave absorber, and a radio wave reflection between the cross-shaped ferrite magnetic material of the cross-shaped radio wave absorber implanted in the mortar layer. The crosspiece-type radio wave absorber unit used in the method for producing a radio wave absorbing precast concrete plate according to claim 6, comprising a fixed anchor penetrating the plate.