JPH05267880A - Radio wave absorption wall - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a radio wave absorption wall that effectively absorbs broadband radio waves and has good durability. [Structure] A concrete wall member 1 such as concrete or mortar is provided, and a plurality of conductor wires 2 or 2, 3 are provided at predetermined positions in the concrete wall member 1 in parallel with the outer surface of the concrete wall member 1. To be embedded at approximately equal intervals. [Effect] Due to the action of the conductor wires 2 or 2 and 3, it is possible to effectively absorb broadband radio waves, and it is not necessary to attach a radio wave absorption plate or the like to the outer wall of a building or the like. When this is carried out, the strength is further strengthened by the action of the conductor wires 2 or 2, and since no plate-like member (for absorbing radio waves) as in the conventional example is used, cracking or shaving The occurrence of accidents can be greatly reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic wave absorbing wall, and more particularly to an electromagnetic wave absorbing wall made of concrete or mortar.

[0002]

2. Description of the Related Art A radio disturbance caused by a high-rise building is displayed on a receiver of a viewer in a so-called ghost form in the case of television radio waves. For this ghost obstacle, generally, an electromagnetic wave absorbing wall is set on the wall surface of a building, for example. As a conventionally known concrete electromagnetic wave absorbing wall, for example, Japanese Patent Publication No.
There are Japanese Patent Publication No. 5-49797 and Japanese Patent Publication No. 55-6320.

Among these, in Japanese Patent Publication No. 55-49797, a plurality of electromagnetic wave absorbing plate elements are arranged between a wide surface of a concrete wall having a metal mesh reinforcing member and the mesh reinforcing member. What is made is disclosed. Further, Japanese Patent Publication No. 55-6320 discloses a structure in which a magnetic material plate is embedded in a building material such as concrete in which magnetic material particles are mixed. All of these have been used as a broadband electromagnetic wave absorption wall in a relatively large amount compared with conventional ones.

[0004]

However, these Japanese Patent Publication No. 55-49797 and Japanese Patent Publication No. 55-6.
In all of those disclosed in Japanese Patent Publication No. 320, since the electromagnetic wave absorber element (magnetic material plate) formed mainly of the ferrite plate is used, the concrete wall itself becomes heavy, and the embedded portion of the ferrite plate is also used. There was a problem that it was easy to separate and break at the boundary. Further, since the ferrite plate is relatively expensive and the work of embedding it in concrete or the like is troublesome, there has been a problem that the cost is greatly increased as a whole.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is to improve the disadvantages of the conventional example, and in particular, to effectively absorb various incoming radio waves having different frequencies and to provide a wide-band radio wave absorbing wall having good durability. To provide.

[0006]

In the present invention, a concrete wall member such as concrete or mortar is provided,
A configuration is adopted in which a plurality of conductor wires are embedded in the concrete wall member at predetermined positions on the same surface at equal intervals. This aims to achieve the above-mentioned object.

[0007]

First, radio waves entering the concrete wall member from the atmosphere are partially reflected by the wall surface and partially attenuated and transmitted to the concrete wall member. Among these, the radio wave transmitted inside the concrete wall member is the surface where the conductor wires are arranged in the electric field direction Ε of the incident radio wave,
Again, a part is reflected in the direction of the front surface of the concrete wall member, but in this case, reflection with large frequency selectivity and small frequency selectivity in the high frequency region occurs, and the reflected wave is reflected to the front surface. Come on. Here, for a radio wave that is transmitted to the inside, reflected on the back surface thereof, and then incident again on the array surface of the conductor lines, the transmission to the front surface side is small in the low frequency region and conversely is large in the high frequency region. It will have frequency dependence.

As described above, by arranging the conductor wires in the concrete wall member, by utilizing the frequency dependence of the magnitude of the reflection or the transmission in the multi-stage reflection or transmission described above, Broadening of the electromagnetic wave absorption band is achieved. As described above, in the present invention, since the plurality of conductor wires are embedded in the concrete wall member itself at substantially equal intervals, setting of a new radio wave absorption wall becomes unnecessary, and a ferrite plate or the like is unnecessary. Since the structure is not buried, accidents such as peeling of the wall part will be eliminated.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 and 2, reference numeral 1 denotes a concrete wall member made of concrete or mortar. This concrete wall member 1
It is formed with a certain thickness and is designed to be used for the walls of buildings and other structures. In the concrete wall member 1, a plurality of conductor lines 2, 2, ... Are equidistantly d on the same surface of a predetermined depth from the surface of the concrete wall member 1 facing the radio wave incident direction. _It is buried in ₁ .

The conductor wire 2 is made of a metal conductor wire in this embodiment, but may be a conductive material such as carbon fiber as long as it is electrically conductive. The buried position of the plurality of conductor lines 2 is based on the wavelength λ of the radio wave having a frequency that easily causes radio interference in the incoming radio waves.
The depth is set to about "λ / 4" to "3λ / 8" (where λ indicates the wavelength of the radio wave propagating in the propagation medium, that is, the concrete wall member). Further, the facility direction of the conductor wire 2 is set to be substantially parallel to the electric field direction Ε of the incoming radio wave.

In a region where the frequency of the incoming radio wave W is low, the concrete wall member 1 is made thin by mixing the concrete wall member 1 with an electromagnetic wave absorbing substance such as carbon particles. be able to. In addition,
In the figure, H indicates the direction of the magnetic field component of the incoming radio wave.

Here, the plurality of conductor lines 2 arranged in the electric field direction Ε reflect incident radio waves. In this case, the magnitude of the reflected radio wave is determined by the distance d ₁ between the arranged conductor lines 2.
Depends on A part of the radio wave incident on the surface on which the conductor wires 2 are arranged is reflected, and another part of the radio wave further penetrates into the concrete wall member 1, and the back surface of the concrete wall member 1 again. Is reflected by.

On the other hand, when the ratio "d ₁ / λ" between the distance d ₁ between the conductor wires 2 and the wavelength λ is small, the reflected radio wave is large, and when "d ₁ / λ" is large, The reflected radio waves are small.
Therefore, the reflection from the surface on which the conductor lines 2 are arranged is large in the low frequency region and small in the high frequency region. Further, the magnitude of transmission when transmitting through the surface on which the conductor lines 2 are arranged is small in the low frequency region and large in the high frequency region.

In the present invention, the frequency dependence of the magnitude of reflection or transmission of the array of conductor lines 2 is utilized, and the operation will be described more specifically. First, a radio wave that has entered the concrete wall member 1 from the atmosphere is partially reflected by the wall surface and partially attenuated and transmitted to the concrete wall member 1. Of these, concrete wall material 1
The electric wave transmitted through the inside of the
On the surface on which the conductor wires 2 are arranged, a part is reflected again toward the front surface of the concrete wall member 1, but in this case, the frequency selection is large in the low frequency region and small in the high frequency region. Reflective waves are reflected on the front surface.

Here, with respect to the radio wave that has been transmitted to the inside, reflected on the back surface thereof, and then incident again on the array surface of the conductor lines 2,
The transmission on the front side becomes small in the low frequency region, and conversely has a large frequency dependence in the high frequency region.

As described above, by arranging the conductor wires 2 in the concrete wall member 1, the frequency dependence of the magnitude of the reflection or the transmission in the multi-step reflection or transmission described above is utilized. As a result, a wide band of the electromagnetic wave absorption band is achieved.

As described above, in this embodiment, since the plurality of conductor wires 2 are embedded in the concrete wall member 1 itself at substantially equal intervals, a radio wave is newly added to the outer surface of the wall member as in the conventional case. Since it is not necessary to provide a wall for absorption, and the structure of burying a ferrite plate or the like is not adopted, accidents such as separation of the wall portion can be significantly reduced.

Further, this embodiment has the following advantages. That is, the construction is almost the same as the conventional method, and the buried metal wire is expected to have the function of reinforcing the strength of the wall, which is beneficial to the improvement of safety. Since no special electromagnetic wave absorbing element is required, stable operation can be ensured for a long period of time. It is economical because a broadband electromagnetic wave absorption wall can be obtained without using a ferrite plate. The reflection of broadband radio waves can be prevented without changing the surface shape of the concrete wall constituting the building wall surface. Since it can be easily combined with the conventional broadband electromagnetic wave absorption wall construction method, it is possible to economically realize a high-performance electromagnetic wave absorption wall.

Next, experimental results (operating frequency 8 to 12 [GHz]) of the embodiment shown in FIG. 1 will be described with reference to FIGS. 3 to 5. First, FIG. 3 shows a test piece embodying FIG. FIG. 4 shows a conventional example used for comparison. Of these, the one shown in FIG. 3 is a concrete wall member 1.
The thickness is 16.4 mm. As the conductor wire 2, a stainless wire having a diameter of 0.3 [mm] was used. The conductor wire 2 is embedded under the condition that the conductor wire 2 has a depth of 2.2 [mm] from the surface on the arrival side of radio waves, and the distance d ₁ between the wires is set to 4.6 [mm]. Further, as shown in FIG. 4, a concrete wall member having a thickness of 16.4 [mm] and having a backing member 10 made of a conductor on its back surface is used.

FIG. 5 shows the frequencies of incident radio waves in the range of 8-12 [G
[Hz]] is shown. This Figure 5
In, the curve A shows the measured value when the conductor wire 2 of FIG. 3 is embedded (this embodiment). Curve B shows the measured value when the conductor wire 2 of FIG. 4 is not buried (conventional example). From this, it was confirmed that in the present example, the radio waves were absorbed over a relatively wide range with respect to radio waves of 9 GHz or higher.

Next, another embodiment will be sequentially described with reference to FIGS. First, in the embodiment shown in FIG. 6, as the plurality of conductor wires shown in FIG.
It has a feature in that every other one is buried. Other configurations are the same as those of the embodiment shown in FIG. 1 described above. By doing so, there is an advantage that the incoming radio wave can be effectively absorbed as in the case of FIG. 1, and further, the thick conductor wire 3 relatively effectively exhibits the radio wave absorbing effect for the low frequency incoming radio wave. There is an advantage of doing.

The embodiment shown in FIG. 7 is characterized in that a plurality of conductor wires 2 shown in FIG. 1 are also embedded in a position close to the back surface side of the concrete wall member 1 to form a two-step arrangement. ing. Other configurations are the same as those of the embodiment shown in FIG. 1 described above. This has the advantage that incoming radio waves can be effectively absorbed under the same conditions on both sides.

In the embodiment shown in FIG. 8, a plurality of conductor wires shown in FIG. 1 are buried also in a position close to the back surface side of the concrete wall member 1, and a plurality of conductor wires 2, 3 having different thicknesses are provided. 2
The feature is that the concrete wall member 1 is formed in a stepwise arrangement and the thickness of the concrete wall member 1 is slightly increased. Further, the conductor wire 3 having the larger diameter has its buried position set relatively deep, and the line interval is set larger than that of the other conductor wires 2. This has the advantage that the incoming radio waves can be effectively absorbed on both sides, as in the case of FIG. 7.

In the embodiment shown in FIG. 9, the embedding intervals of a plurality of conductor lines are set to be the same as in the case shown in FIG. 7, and the diameters of adjacent conductor lines are set to be different every other. It has a feature in the point. The other structure is the same as that of the embodiment shown in FIG. By doing so, in addition to the case of FIG. 7, it is possible to effectively absorb the incoming radio waves on the both sides under the same condition, and to more effectively exhibit the radio wave absorbing effect on the incoming radio waves of a low frequency on both sides. There is an advantage that.

The embodiment shown in FIG. 10 is characterized in that the back side of the embodiment of FIG. 1 is lined with a backing member 10 such as a metal plate. Regarding this backing member 10,
In addition to the metal plate, a metal mesh having a dense mesh may be used. Further, the embodiment shown in FIG. 11 is characterized in that the conductor wires 3 having a large diameter are arranged more densely than the conductor wires 2 having a small diameter in the embodiment shown in FIG. Other configurations are the same as those of the embodiment of FIG. 1 described above in any of FIGS. Even in this case, it is possible to obtain a wide-band electromagnetic wave absorbing wall as in the case of each of the above-described embodiments.

Further, in each of the above-mentioned embodiments shown in FIGS. 6 to 11, when a radio wave absorbing substance such as carbon particles is mixed in the concrete wall member 1, the incoming radio wave is received as in the case of FIG. 1 described above. It is possible to more effectively absorb radio waves in the low frequency region of W, and the thickness of the concrete wall member 1 can be set thin when the same radio wave absorption effect is obtained. There is.

In the embodiment shown in FIG. 12, a concrete wall member 1 such as concrete or mortar is provided, and at a predetermined position in the concrete wall member 1, a plurality of parallel wall members are provided in parallel with the outer surface of the concrete wall member 1. It is characterized in that the conductor wires 2 are buried at substantially equal intervals to form a wall constituent member 1A, and the wall constituent member 1A is buried in an exterior member 20 such as concrete or mortar. In the concrete wall member 1 and the exterior member 20, a radio wave absorbing material such as carbon particles is mixed. Further, in this case, one or both of the concrete wall member 1 and the exterior member 20 in which carbon particles are not mixed may be used. As for the exterior member 20, one in which carbon particles are not mixed may be used. As the wall component member 1A embedded in the exterior member 20, a concrete wall member 1 of the same size may be used in a laminated form. Further, regarding the conductor wire 2, the above-described FIG. 6 to FIG. 9 and FIG.
It may be arranged as follows.

Further, regarding the embodiment shown in FIG. 12, in an actual construction site, etc., it can be used as it is as a constituent member of the outer wall, and positioning and the like can be performed quickly and accurately. It is possible to arbitrarily select and use the wall component member 1A incorporating the conductor wires 2 (or the conductor wires 2 and 3) having a pitch that matches the construction site and the like.
There is an advantage that the workability can be improved.

Further, as the conductor lines 2 and 3 used in the embodiments of the above-mentioned respective drawings, the case where the conductor lines 2 and 3 are both linear or linear is illustrated, but the present invention is not necessarily limited to this. For example, some or all of the plurality of conductor lines 2 and 3 are loop-shaped (see FIG. 13,
(See FIG. 14).
Further, each of the conductor lines 2 and 3 may be provided with unevenness (see FIGS. 15 and 16) along the longitudinal direction thereof. Regarding the lengths of the conductor lines 2 and 3, long conductors may be used as a whole or short conductor conductors may be arranged discontinuously on the same line.

The direction in which the conductor lines 2 and 3 are buried differs depending on the type of radio wave, but if they are horizontally polarized, they are arranged horizontally with respect to the ground, and if they are vertically polarized, they are arranged vertically with respect to the ground. Is being used by Also, the conductor wires 2, 3
With respect to the above, the arrangement is performed as disclosed in each of the above-described embodiments, and the above-mentioned conductor lines are connected to each other at the upper and lower end portions of the concrete wall member 1 or any one end portion thereof with the same conductor wire. You may connect. This has the advantage that incoming radio waves can be absorbed more effectively. Regarding the conductor lines 2 and 3, as a modification,
It is also possible to embed a previously assembled cloth in a cross shape. Further, the material of the conductor wire used in the present invention is not limited to those shown in the examples, for example, as long as it is stable and does not cause corrosion or the like against concrete or mortar, The material is not particularly limited.

[0031]

As described above, according to the present invention, by the action of the conductor wire in the concrete wall member, it is possible to effectively absorb the broadband radio wave, and the building wall member itself has the radio wave absorbing function. By using this, there is no need to attach a radio wave absorption plate etc. to the outer wall of a building etc., and if this is done for conventional reinforced concrete, the strength is further strengthened by the action of the conductor wire, and Since no plate-shaped member (for electromagnetic wave absorption) like the conventional example is used, it is possible to greatly reduce the occurrence of cracks, abrasion accidents, etc. Further, it is possible to provide an unprecedented excellent electromagnetic wave absorption wall capable of exhibiting a wide band electromagnetic wave absorption function for various incoming radio waves having different frequencies.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line BB of FIG.

FIG. 3 is a cross-sectional view showing the experimental test piece of FIG.

4 is a cross-sectional view showing a conventional example for comparison with the experimental test piece of FIG.

5 is a diagram showing measured data for FIGS. 3-4. FIG.

6 to 12 are cross-sectional views showing other embodiments.

13 to 16 are cross-sectional views showing other examples of conductor lines.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Concrete wall member 1A Wall constituent member 2,3 Metal wire rod as conductor wire 10 Backing member 20 Exterior member

Claims (15)

[Claims] 1. A concrete wall member, such as concrete or mortar, is provided, and a plurality of conductor wires are embedded in the concrete wall member at predetermined positions in parallel with the outer surface of the concrete wall member at substantially equal intervals. Electromagnetic wave absorption wall characterized by having done. 2. A concrete wall member such as concrete or mortar is provided, and a plurality of conductor wires are embedded in the concrete wall member at predetermined positions in parallel with the outer surface of the concrete wall member at substantially equal intervals. Then, a wall constituent member is formed, and the wall constituent member is embedded in an exterior member such as concrete or mortar. 3. The radio wave absorbing wall according to claim 2, wherein a radio wave absorbing substance such as carbon particles is mixed in the exterior member. 4. The electromagnetic wave absorbing wall according to claim 1, wherein the concrete wall member is mixed with an electromagnetic wave absorbing substance such as carbon particles. 5. The buried position of the conductor wire is set to a depth corresponding to about a quarter wavelength from the surface on the radio wave arrival side. The radio wave absorption wall described. 6. The buried position of the conductor wire is set to a depth corresponding to about ¼ wavelength to ⅜ wavelength from the surface on the radio wave arrival side. The electromagnetic wave absorbing wall according to item 1, 2, 3, 4 or 5. 7. The plurality of conductor lines are embedded in two layers at a predetermined interval.
The electromagnetic wave absorbing wall according to 2, 3, 4, 5 or 6. 8. The diameter of the conductor wire of one layer and the diameter of the conductor wire of the other layer of the plurality of conductor wires embedded in the two layers are set to be the same size. The radio wave absorption wall according to claim 7, characterized in that. 9. The diameter of the conductor wire of one layer among the plurality of conductor wires embedded in the two layers is set to be larger than the diameter of the conductor wire of the other layer. The electromagnetic wave absorbing wall according to claim 7. 10. The embedded conductors are arranged such that the diameters of the plurality of conductor wires are different from the diameters of other conductor wires adjacent to each other. 6, 7, 8
Alternatively, the radio wave absorption wall described in 9. 11. The plurality of conductor lines are formed in a concavo-convex shape along the longitudinal direction thereof, and are used. , 7,
The radio wave absorption wall according to 8, 9, or 10. 12. A conductor wire formed in a coil shape along a longitudinal direction of the plurality of conductor wires is used. , 7,
The electromagnetic wave absorbing wall according to 8, 9, or 10. 13. The plurality of conductor wires are partially or wholly connected to each other at an end of the concrete wall member. ，
The electromagnetic wave absorption wall according to 6, 7, 8, 9, 10, 11 or 12. 14. The method according to claim 1, wherein the plurality of conductor wires are formed of a metal member.
3,4,5,6,7,8,9,10,11,12 or 1
The electromagnetic wave absorption wall described in 3. 15. The conductor wires of claim 1, wherein the conductor wires are made of a conductive material such as carbon fiber. , 1
The electromagnetic wave absorption wall according to 0, 11, 12, 13 or 14.