JP3712256B2 - Radio wave absorption panel - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a radio wave absorption panel, and more particularly, to a radio wave absorption panel that is attached to an outer wall surface of a building or the like that causes a reflection failure of a TV radio wave and absorbs radio waves and that has a tiled appearance.
[0002]
[Prior art]
Television obstacles due to high-rise buildings are classified into “building shadow obstacles” that occur when radio waves are blocked by buildings, and “television ghost obstacles” that occur due to reflected radio waves from the walls of buildings.
For the building shadow failure, measures are taken by CATV and the like because the range is relatively small. However, in the case of a skyscraper, a TV ghost failure due to reflected radio waves occurs not only over a very wide area, but also a complex combined reflection failure due to a forest of high-rise buildings is expected. For this reason, it is necessary to take anti-reflection measures for the building itself, which is the source, and the method of constructing the wall surface with a radio wave absorber is the most effective.
In VHF / UHF, which is a television frequency band, ferrite is listed as an excellent radio wave absorber having thin and wide band characteristics.
By the way, in terms of the radio wave absorbing function, the radio wave absorbing wall body has a restriction that the radio wave absorbing material (tile) must be continuously coupled at least in the direction of the magnetic field of the radio wave. Therefore, there is a contradictory constraint such as a gap in the joint part inevitably (excluding a sleep joint).
For this reason, conventionally, a precast panel wave absorber for countermeasures against TV radio wave interference that suppresses reflection of TV radio waves in buildings such as buildings has a ceramic tile (decorative tile) attached to the exterior material and has radio wave absorption performance on the back side. A so-called built-in ferrite plate + porcelain tile finish type radio wave absorber in which ferrite plates are continuously arranged in the direction of the magnetic field / electric field of radio waves has been proposed.
Further, the ferrite plate (tile) has an excellent radio wave absorption performance with a return loss of 15 dB or more in a wide band covering the VHF band (90 to 222 MHz) and the UHF band (470 to 770 MHz).
However, in the wave absorber of the precast panel in which this ferrite plate (tile) is placed inside, the porcelain tile placed on the outer surface and the intermediate concrete or mortar are obstructions, and the wave absorbing performance of the ferrite tile is descend. In particular, the absorption bandwidth is narrowed.
For this reason, a precast panel radio wave absorber for TV radio wave interference countermeasures corresponding to each VHF band or UHF band has been proposed.
[0003]
In addition, when using ferrite tiles that have radio wave absorption performance for the exterior, if there is a gap between the ferrite tiles arranged in the direction of the magnetic field of the radio waves due to mortar joints, etc., and the ferrite tiles become discontinuous, the radio wave absorption performance of the VHF band Has been reported to decrease significantly.
[0004]
[Problems to be solved by the invention]
In the electromagnetic wave absorber of the above ferrite plate built-in + porcelain tile finish type, as described above, the porcelain tile located on the surface of the ferrite plate and the mortar to which it is attached become an obstacle, and the electromagnetic wave absorption efficiency of the ferrite plate is extremely high. Although it is reduced, in order to ensure the radio wave absorption efficiency, it can be dealt with to some extent by increasing the thickness of the ferrite plate, but there are problems such as the wall thickness and the weight becoming vast. Even if the thickness of the ferrite plate is increased, there is a problem that the center frequency to be absorbed is shifted from the target.
In addition, when using a ferrite plate directly for the exterior, there is currently no method other than applying the conventional tiling method as it is, and as a result, the ferrite plate has a gap in the magnetic field direction of the radio wave at the joint as described above. Absorption performance decreases. In order to maintain radio wave absorption performance, it is conceivable to arrange ferrite plates continuously. However, in that case, a joint having a gap in the direction of the magnetic field of the radio wave cannot be formed, and there are problems such as restrictions on the design. There is.
Furthermore, in recent years, terrestrial digital broadcasting using the UHF band is planned, and it is expected that both radio waves in the VHF band and the UHF band will arrive from the same direction for a certain period.
Conventionally, it has only been necessary to consider measures against TV radio wave interference in the VHF band. However, in the future, a precast panel radio wave absorber that absorbs radio waves over a wide band in the VHF band and the UHF band will be required.
[0005]
The present invention has been made in view of this point, and an object of the present invention is to use a radio wave absorber for an exterior of a building in the same manner as a normal exterior tile, and to provide a design function as an exterior tile and radio wave absorption. An object of the present invention is to provide a light-weight and thin wave-absorbing panel for forming a building wall having a function of absorbing radio waves by a material.
Another object of the present invention is to provide a radio wave absorption panel that can effectively exhibit the performance of absorbing the radio waves of both the VHF band and UHF band inherently possessed by the ferrite tile.
[0006]
[Means for Solving the Problems]
The technical means taken by the present invention in order to achieve the above object is a radio wave absorption panel attached to a radio wave incident surface of a building, and a tile formed of a radio wave absorber is provided outside the panel in the direction of the magnetic field of the radio wave. And an auxiliary plate made of a radio wave absorber that establishes continuity in the magnetic field direction of the radio wave on the back side of the tile, and is arranged behind the tile. A reflector is arranged, and the tile, the auxiliary plate, and the radio wave reflector are filled with a binder to be integrated.
The auxiliary plate that establishes continuity of the magnetic field direction of the radio wave in the tile is a strip-like plate that is continuous in the magnetic field direction of the radio wave, and is disposed along the magnetic field direction of the radio wave on the back side of the tile arranged in a discontinuous state. Examples include a form or a small piece form, which is arranged for each horizontal joint portion of the tile.
The joints referred to in the present invention include not only joints that form gaps between tiles, but also sleep joints that have almost no gaps.
In addition, the auxiliary plate made of the electromagnetic wave absorber in the panel is secured to the continuity of the magnetic field direction of the auxiliary plate of each panel arranged along the magnetic field direction when the panel is attached to the wall surface of the building. The joint is configured as follows. As the structure of the joint that ensures the continuity, for example, one end of the auxiliary plate protrudes from the joint (male side), the other end is submerged from the joint (female side), and the auxiliary plate is joined by joining the panels. Make contact with each other so that they are continuous.
However, if the width of the panel in the magnetic field direction is longer than the wavelength of the television frequency band, there is no need to dare to ensure the continuity of the auxiliary plate in the magnetic field direction. An auxiliary plate may be embedded in the panel.
[0007]
The auxiliary plate has a thickness of 20% or more of the thickness of the radio wave absorber (tile), the width in the electric field direction is 15% or more of the width in the electric field direction of the tile and less than the width in the electric field direction of the tile, Further, the interval between the auxiliary plates in the direction of the electric field is 85% or less with respect to the width of the tile in the direction of the electric field.
The auxiliary plate may be any material as long as it has a capability of absorbing radio waves, and of course, a ferrite plate made of the same material as the radio wave absorber of the exterior material is suitable. The auxiliary plate is arranged in contact with the back surface of the tile.
Furthermore, a ferrite material is suitable as the radio wave absorber forming the tile, and a ferrite tile with glaze is effective. It is assumed that the ferrite tile with glaze is subjected to glaze having a small linear expansion coefficient in the range of 0.1 to 30% compared to the linear expansion coefficient of the ferrite sintered body. Preferably, it shall be small in the range of 10 to 20%. When the linear expansion coefficient of the glaze is larger than the ferrite sintered body, penetration (fine cracks) occurs in the glaze after firing.
Also, if the linear expansion coefficient of the glaze is 30% or more smaller than the linear expansion coefficient of the ferrite sintered body, the difference from the linear expansion coefficient of the ferrite sintered body becomes too large. Causes warping and cracking of the substrate.
The radio wave reflector may be any material that can reflect radio waves, and a round bar-shaped reinforcing bar is generally used. The radio wave reflector also acts as a reinforcing bar for the panel itself, and may be a square bar, a strip or the like.
The panel is filled with a binder between the tile, the auxiliary plate, and the radio wave reflector, the auxiliary plate and the radio wave reflector are embedded in the panel, and the tile is exposed to the outer surface of the panel. It is integrally formed.
Moreover, concrete or mortar can generally be used as a binding material for integrating the tile, auxiliary plate, and radio wave reflector.
[0008]
According to the above means, the auxiliary plate made of a radio wave absorber that establishes continuity in the magnetic field direction of the radio wave is placed in contact with the back surface of the tile formed of the radio wave absorber of the exterior material, and thereby the mortar joint of the tile The electromagnetic field direction discontinuity becomes a continuous state via the auxiliary plate, and can constitute a radio wave absorption panel having both a design function in which joints appear and a radio wave absorption function. And the fall of the electromagnetic wave absorption performance in the VHF band of an electromagnetic wave absorber (tile) can be prevented. In addition, the arrangement interval of the electromagnetic wave absorber (ferrite tile) in the electric field direction is generally about 33% apart from the width of the electric field direction of the ferrite tile when the thickness of the electromagnetic wave absorber (ferrite tile) is constant. Has also been reported to have no effect on radio wave absorption performance.
Furthermore, the auxiliary plate placed in contact with the back surface of the tile can satisfy the required performance of radio wave absorption even if the width is 15% or more of the tile width and the thickness is at least 20% of the tile thickness. did it.
Moreover, the glaze applied to the surface of the ferrite tile is made small in the range of 0.1 to 30% of the linear expansion coefficient of the ferrite sintered body, thereby completing the ferrite tile with glaze firmly attached to the glaze. Thus, a radio wave absorbing tile having a rich design can be obtained.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.
1 and 2 show a part of a radio wave absorption panel A according to the present invention, in which 1 is a ferrite tile with glaze disposed on the radio wave incident surface (outer surface) of the radio wave absorption panel A, 2 Is an auxiliary plate made of a radio wave absorber disposed in contact with the back surface of the ferrite tile with glaze 1 along the direction of the magnetic field of radio waves, 3 is a radio wave reflector disposed behind the auxiliary plate 2, Concrete is used as a binding material that integrates the ferrite tile 1 with glaze, the auxiliary plate 2, and the radio wave reflector 3 to form the base of the panel A.
The periphery of the ferrite tile 1 with glaze is surrounded by a joint material 4 ′, and the magnetic field direction and electric field direction of the radio wave are formed in a discontinuous state.
[0010]
The ferrite tile 1 with glaze is obtained by forming a surface layer 1 ′ made of glaze or frit on the surface of a rectangular (vertical: 45 mm, horizontal: 95 mm) tile made of ferrite plate (see FIG. 2). .
As the surface layer 1 ′, for example, a layer that erases the color (black) of the ferrite plate is applied to the surface of the ferrite plate, and then fired, and further, a glaze is further applied to the surface of the ferrite plate. It is possible to produce an exterior tile made of ferrite with the surface color, that is, a ferrite tile with glaze.
The glaze applied to the ferrite sintered body is a glaze having a small linear expansion coefficient in the range of 0.1 to 30% compared to the linear expansion coefficient of the ferrite sintered body. Preferably, it shall be small in the range of 10 to 20%. When the linear expansion coefficient of the glaze is larger than the ferrite sintered body, penetration occurs in the fired glaze. Further, if the linear expansion coefficient of the glaze is 30% or more smaller than the linear expansion coefficient of the ferrite sintered body, the difference from the linear expansion coefficient of the ferrite sintered body becomes too large. Warpage and ground cracking occur.
[0011]
Hereinafter, the manufacturing method of the glaze-attached ferrite tile will be briefly described.
(1) Apply [first glazing and sinter] to the surface of the tile made of sintered ferrite plate. A glaze containing alumina, zirconia, tin oxide (thing to make white) and other pigments (thing which gives an arbitrary color) is applied, and firing is performed at a temperature lower than the sintering temperature of the ferrite plate. (In this state, the side surface is not glossy: matte surface) And this layer needs about 200 μm.
(2) Next, apply [second glazing and smoldering]. On the molding layer, a glaze for giving a further gloss is applied, and then it is sintered and sintered (the temperature here is also sintered at a temperature lower than the ferrite sintering temperature), thereby giving a ferrite having an arbitrary color with a gloss. An exterior tile made of a plate (ferrite tile with glaze) can be produced. The gloss level (mud level) on the exterior tile surface can be arbitrarily adjusted by the amount of gloss glaze applied.
[0012]
And the dovetail groove | channel 5 of the predetermined depth is formed in the transversal length full length on both sides of the back surface of the said ferrite tile 1 with a glaze, and the back surface of the ferrite tile 1 with a glaze is comprised by the dovetail shape by it. In other words, the dovetail grooves 5 are provided on both sides of the contact surface of the auxiliary plate 2 made of the above-described radio wave absorber. Thereby, while increasing the adhesive strength of the concrete of the ferrite tile 1 with a glaze and the binder 4, the weight of the ferrite tile 1 can be reduced. In addition, the back surface of the ferrite tile 1 with glaze is not limited to the illustrated dovetail shape, but may be a flat surface, but it is effective to have an uneven surface in consideration of adhesion to the base concrete. .
[0013]
The auxiliary plate 2 placed in contact with the back surface of the glaze-attached ferrite tile 1 is formed by forming a ferrite plate of a radio wave absorber in a narrow band like the above-described ferrite tile 1 with glaze, and the magnetic field direction is a joint 4 ′. It arrange | positions in the continuous state in the magnetic field direction of an electromagnetic wave along the back surface of the ferrite tile 1 with a glaze arrange | positioned in a discontinuous state.
By this auxiliary plate 2, the glaze-equipped ferrite tiles 1 whose magnetic field directions are discontinuous are held in a continuous state.
Moreover, the structure which contacts and arranges this auxiliary | assistant board 2 on the back surface of the ferrite tile 1 with a glaze is fixed with an adhesive agent.
[0014]
The dimension of the auxiliary plate 2 is to make the discontinuity in the magnetic field direction of the radio wave of the glaze-attached ferrite tile as described above so that the required radio wave absorption performance is satisfied. The width L in the direction is 15% or more of the width L ′ in the electric field direction of the ferrite tile 1 with glaze and less than the width L ′ in the electric field direction of the tile 1, and the thickness T of the auxiliary plate 2 is at least the thickness of the ferrite tile 1 with glaze 20% or more of the length T ′.
In addition, the auxiliary plate 2 made of the electromagnetic wave absorbing material in the panel A, when the panel A is attached to the wall surface of the building, the auxiliary plate 2 of each panel A arranged along the magnetic field direction The joints are configured to ensure continuity. As a configuration of the joint for ensuring the continuity, for example, one end of the auxiliary plate arranged in the magnetic field direction protrudes from the edge of the panel by a predetermined length (male side), and the other end extends from the edge of the panel. A fitting hole having a depth into which the protruding auxiliary plate is inserted is provided (female side), and the auxiliary plates come into contact with each other by joining the panels so that continuity is established.
[0015]
Next, the method for forming the above-described radio wave absorption panel A will be briefly described with reference to FIG. 3. The glaze-attached ferrite tile 1 is opposed to the bottom surface of the panel-forming frame 6 with the surface layer 1 'facing the bottom surface. Thus, gaps (joints) are arranged in a discontinuous state in the magnetic field direction and electric field direction of the radio wave, and the auxiliary plate 2 is placed in contact along the magnetic field direction of the radio wave on the back surface of the glazed ferrite tile 1. When the auxiliary plate 2 is placed in contact with the back surface of the glazed ferrite tile 1, it is bonded and fixed with an adhesive so that it does not move when the concrete 4 is poured into the frame 6. In addition, when fixing with an adhesive, the ferrite tile 1 with glaze and the auxiliary plate 2 are strictly speaking not in a contact arrangement, but within the range where the decrease in radio wave absorption efficiency falls within the usable range, It is good also as a non-contact arrangement via.
Further, a radio wave reflector 3 is disposed on the auxiliary plate 2, and then a concrete of the binder 4 serving as a base of the panel A is poured, and after curing, it is demolded to obtain a radio wave absorbing panel A. Before placing the concrete of the binding material 4, first, mortar is placed, and the gap between the glazed ferrite tiles 1 is filled to form a joint 4 ′. Concrete is cast to form panel A.
[0016]
4 and 5 show another example of establishing the continuity of the glaze-attached ferrite tile 1 in which the magnetic field direction is discontinuously arranged at the horizontal joint 4′a, and the auxiliary plate 2 ′ has at least the horizontal joint 4 ′. The auxiliary plate 2 'is formed in the shape of a small piece wider than the width of a, and the auxiliary plate 2' is bridged on the back side of the glaze-attached ferrite tile 1 in which the magnetic field direction is discontinuously arranged across the horizontal joint 4'a. To do. Thereby, the ferrite tiles with glaze 1 arranged in a discontinuous state at the horizontal joint 4′a are connected to each other by the small auxiliary plate 2 ′, and the continuity of the magnetic field direction is established.
[0017]
By sticking the radio wave absorption panel A configured as described above to the wall surface of the building, the TV radio wave absorption wall surface can be constructed with the same mortar joint pattern and color tone as the porcelain tile. In addition, it is possible to make use of the radio wave absorption performance over a wide band inherent in the ferrite tile.
FIG. 6 is a diagram showing the radio wave absorption characteristics of the radio wave absorption panel A shown in FIGS. 1 and 2, and the discontinuity rate in the magnetic field direction of the glaze-attached ferrite tile 1 is 10 times the vertical width of the glaze-use ferrite tile. %, On the back side of the ferrite tile, (1) no auxiliary plate, (2) with auxiliary plate (width L in the electric field direction: 12.3%), (3) with auxiliary plate (width L in the electric field direction: 31) 4%) and {circle around (4)} with auxiliary plates (width L in the electric field direction: 49.6%).
As is clear from the figure, (1) shows a return loss of 15 dB or more in a part (about 700 Mhz or more) of the UHF band (470 to 770 MHz), but the radio wave absorption performance is inferior in a low frequency region below that. Yes. In addition, (2) is a part of the low frequency region of the VHF band (90 to 222 MHz), which is less than the return loss of 15 dB. However, in the higher frequency region, the return loss is 15 dB or more, and excellent radio wave absorption performance is obtained. . In (3), excellent radio wave absorption performance with a return loss of 15 dB or more is obtained in both the VHF band and the UHF band. {Circle around (4)} exhibits excellent radio wave absorption performance with a return loss of 15 dB or more in the VHF band. However, in the high frequency region of the UHF band, the return loss is less than 15 dB, and the radio wave absorption performance decreases.
That is, when the width of the auxiliary plate in the electric field direction is widened, excellent radio wave absorption performance is exhibited in the low frequency region of the VHF band, but radio wave absorption performance is degraded in the high frequency region of the UHF band. Conversely, if the width is narrowed, excellent radio wave absorption performance is exhibited in the UHF band, but radio wave absorption performance is degraded in the low frequency region of the VHF band.
Therefore, to obtain excellent radio wave absorption performance in the VHF band and UHF band, set the width as shown in (3). To increase the radio wave absorption performance in the VHF band, set the width wide, and in the UHF band In order to improve the radio wave absorption performance, set the width according to the purpose, such as setting the width narrower.
[0018]
FIG. 7 shows the radio wave absorption characteristics when the discontinuity rate in the magnetic field direction of the ferrite tile with glaze is changed. (1) Magnetic field direction discontinuity width: 0% (continuous), (2) Magnetic field direction discontinuity width: 4%, {circle around (3)} magnetic field direction discontinuity width: 8%, {circle around (4)} magnetic field direction discontinuity width: 10%.
As can be seen from the figure, when the magnetic field spacing between the glazed ferrite tiles is 0% discontinuous (continuous), an excellent radio wave with a return loss of 15 dB or more in a wide range of VHF band and UHF band. Whereas the absorption performance is obtained, when the magnetic field direction is discontinuous, an excellent radio wave absorption performance of 15 dB or more in the UHF band is obtained, but in the VHF band, the radio wave absorption is less than 15 dB and the radio wave absorption. It turns out that performance falls.
That is, even if the magnetic field direction is discontinuous at the joint, the radio wave absorption effect is exhibited at the frequency in the UHF band, but the radio wave absorption effect is not exhibited in the VHF band. However, the installation of the auxiliary plate described above can improve the radio wave absorption performance in the VHF band.
[0019]
【The invention's effect】
According to the radio wave absorption panel of the present invention, the discontinuous state of the tile in the magnetic field direction of the radio wave generated by the formation of the joint pattern is eliminated by the auxiliary plate formed of the radio wave absorber. Because the state is secured, it has the same mortar joint pattern and color appearance as a commonly used porcelain tile, but it exhibits radio wave absorption performance over a wide band covering the VHF band and UHF band inherent to radio wave absorbers. It is possible to provide a radio wave absorbing panel capable of
In addition, since the auxiliary plate is disposed in contact with the back surface of the tile according to the configuration described in claim 4, the electromagnetic wave joining panel can be reliably secured and the radio wave absorbing panel that reliably exhibits the required radio wave absorbing performance is configured. be able to.
In addition, by adjusting the width of the auxiliary plate according to the configuration described in claim 5, it is possible to configure a radio wave absorption panel that can satisfy the required performance for VHF band, UHF band, and both bands. it can.
Further, since the radio wave absorber is made of ferrite according to the configuration described in claim 6, it is possible to provide a radio wave absorption panel that stably exhibits excellent radio wave absorption performance.
Furthermore, the arrangement according to claim 7, glazed with ferrite tiles glaze arrived firmly is formed, exterior stable wave absorbing panel can be obtained.
[Brief description of the drawings]
FIG. 1 is a front view showing a part of a radio wave absorption panel according to the present invention.
FIG. 2 is an enlarged cross-sectional view taken along line (2)-(2) in FIG.
FIG. 3 is an exploded perspective view showing panel molding.
FIG. 4 is a front view showing another example of auxiliary plate attachment.
5 is an enlarged cross-sectional view taken along line (5)-(5) in FIG.
FIG. 6 is a radio wave absorption characteristic diagram of the radio wave absorption panel according to the present invention.
FIG. 7 is a radio wave absorption characteristic diagram of the magnetic field direction discontinuity rate of the ferrite tile with glaze.
[Explanation of symbols]
A ... Panel for absorbing radio waves 1 ... Tile (ferrite tile with glaze)
2, 2 '... auxiliary plate 3 ... reflex bar 4 ... binding material (concrete) 4' ... joint L ... electric field direction width of auxiliary plate T ... auxiliary plate thickness L '... magnetic field direction of tile (ferrite tile with glaze) Width T '... Thickness of the tile (ferrite tile with glaze)

Claims (7)

  A radio wave absorption panel attached to a radio wave incident surface, wherein tiles formed of a radio wave absorber are arranged outside the panel at intervals in a discontinuous state in a magnetic field direction and an electric field direction of the radio wave, An auxiliary plate made of a radio wave absorber that establishes continuity in the magnetic field direction of radio waves is arranged on the back surface, and a radio wave reflector is arranged behind it, and is coupled between the tile, the auxiliary plate, and the radio wave reflector. An electromagnetic wave absorption panel characterized by being integrated by filling materials.   2. The radio wave absorption panel according to claim 1, wherein the auxiliary plate for establishing continuity in the magnetic field direction of the radio wave in the tile is a belt-like plate continuous in the magnetic field direction of the radio wave.   2. The radio wave absorption panel according to claim 1, wherein the auxiliary plate that establishes continuity in the magnetic field direction of the radio wave in the tile is a small piece, and is arranged for each horizontal joint portion of the tile.   The radio wave absorption panel according to any one of claims 1 to 3, wherein the auxiliary plate is disposed in contact with the back surface of the tile.   The auxiliary plate has a thickness of 20% or more of the thickness of the tile, and the electric field direction width is 15% or more of the tile electric field direction width and less than the tile electric field direction width. The radio wave absorption panel according to any one of claims 1 to 4.   The radio wave absorption panel according to claim 1, wherein the radio wave absorber is ferrite.   The tile is characterized in that the surface of the ferrite sintered body is coated with a glaze having a small linear expansion coefficient in the range of 0.1 to 30% compared to the linear expansion coefficient of the ferrite sintered body. The radio wave absorption panel according to any one of claims 1 to 6.

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