JPH10117087A - Structure for reducing reflection interference of building - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the effect of a radio-wave absorbing wall by preventing the reflection of radio waves by providing the absorbing wall, having magnetic radio wave absorbing members on the external surface of a building and positioning a radio-wave reflecting structure which is exposed on the external surface of the building on the rear side of the front faces of the absorbing members in the arriving direction of the ration waves. SOLUTION: At the time of constructing a radio-wave absorbing wall 40, exterior materials 43, such as exterior tiles, etc., are put on the front faces of ferrite tiles 41 which are used as magnetic radio wave absorbing members, so as to prevent the falling down of the tiles 41 and the tiles 41 and 43 are united in one body by placing concrete 45 on the rear-surface side of the tiles 41. A window frame is constituted of an aluminum sash 50. Since the horizontal section 50A of the sash 50 which is parallel to the electric field direction of arriving radio-waves works as a radio wave reflecting body, the sash 50 is fitted to the structure of a tall building, so that the horizontal section 50A can be positioned more or less on the rear side of the rear surfaces ferrite tiles 41 which are used as the magnetic radio wave absorbing members of the wall 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a building in which a radio wave absorbing wall having a magnetic wave absorbing member such as a ferrite tile is provided on an outer wall surface in order to prevent radio wave reflection obstruction such as television ghost obstruction of the building. In order to solve the problem of radio wave reflection obstruction of a building by preventing the radio wave reflection by devising the mounting structure of the radio wave reflecting structure exposed on the outer wall surface which cannot be handled by the radio wave absorbing wall, further enhancing the effect of the radio wave absorbing wall The present invention relates to a structure for reducing a reflex obstruction of a building which aims at the above.

[0002]

2. Description of the Related Art Conventionally, a radio wave absorbing wall as shown in FIG. The radio wave absorbing wall shown in FIG. 7 is provided with a special legged exterior tile (porcelain tile, etc.) 3 which also serves as a magnetic wave absorbing member to prevent the ferrite tile (ferrite plate) 1 from dropping, and covers the front of the ferrite tile 1. A reinforcing rod 4 forming a metal reflection mesh (radio wave reflector) is arranged behind the tile 1 and concrete 5 is cast on the back side of the ferrite tile 1 to constitute a precast curtain wall structure radio wave absorbing wall. .

The radio wave absorbing wall shown in FIG. 7 is currently widely used as a countermeasure for TV ghost on the outer wall of a building.
It has been clarified that the use of this radio wave absorbing wall can significantly reduce radio wave reflection disturbance.

However, an actual building has, for example, a metal sash of a window frame, a gondola rail, and the like irrespective of the operation requirements as a radio wave absorbing wall. The effect of preventing the reflection of radio waves varies greatly depending on the type. The reason is that there is no effective anti-reflection method for radio wave reflecting structures exposed on the outer wall of the building such as window frames. Therefore, at present, even if a radio wave absorption wall having excellent radio wave absorption characteristics is used, the radio wave reflection of a building cannot be solved by itself. For this reason, the reflection of radio wave reflecting objects caused by the structure of the building that cannot be handled by the radio wave absorbing wall is approved, and the obstacles caused by this are taken separately from CATV and other measures other than the measures to prevent radio wave reflection obstacles on the building side. I have. Depending on the structure of a radio wave reflecting object such as a window frame of a building, the effect of adopting a radio wave absorbing wall may not be expected.

[0005]

When a conductive structure such as a window frame of a building is arranged in parallel with an electric field of an incoming radio wave, it functions as a kind of antenna and functions as a large radio wave reflector. 8 and FIG. 9 and FIG. 10 which are enlarged views of the circle P in FIG. 8 show two rectangular radio wave absorbing panels 10A and 10B (4000 mm long and 3 mm wide, respectively) as radio wave absorbing walls.
150 mm) and the two radio wave absorbing panels 10
A gap of 100 mm is provided between A and 10B, and a single (independent) radio wave absorbing panel 10A and 10B is provided in this gap.
This shows a structure in which a rail-shaped metal reflector (which can be considered as simulating a horizontal portion of a window frame) 11 is attached in parallel to the direction of the electric field of an incoming radio wave. However, in FIGS. 9 and 10, 1 is a ferrite tile, 3 is an exterior tile as an exterior material covering the front surface of the ferrite tile, 4 is a reinforcing bar forming a metal reflection mesh (radio wave reflector), and 5 is concrete.

FIG. 11 shows the radio wave absorption characteristics (curve A) of the two radio wave absorbing panels 10A and 10B themselves having a gap of 100 mm, and a rail-shaped metal reflector in the gap of 100 mm as shown in FIGS. Radio wave absorption characteristics (curve B) when 11 is arranged are shown as frequency characteristics of return loss. By installing a rail-shaped metal reflector in the joint gap of two radio wave absorption panels that have excellent radio wave absorption characteristics of about 20 dB at 100 MHz, the characteristics deteriorate to about 15 dB, as if radio wave absorption The panel itself is the same as a panel having a characteristic of about 15 dB.

Therefore, in the case of measures against reflection of radio waves from general structures, measures against reflectors parallel to the direction of the electric field of incoming radio waves, such as metal rods and metal rails, are considered to be the most important. On the other hand, a method of covering with a radio wave absorber or replacing with a non-conductive material other than metal, for example, a reinforced plastic containing glass fiber or the like is used.

However, due to the structure and purpose of use of window frames and the like of buildings, it is not possible to take measures such as covering these structures with radio wave absorbers, and new materials that can be replaced with non-conductive materials. Is not found at present. Therefore, countermeasures against radio wave reflecting structures existing on the outer wall of a building where it is impossible to take countermeasures with window frames or other radio wave absorbers have become a major issue, and this solution is the main subject of the present invention. It is.

In view of the above, the present invention devises a mounting structure of a radio wave reflecting structure exposed on the outer wall of a building which cannot be handled by a radio wave absorbing wall, thereby preventing radio wave reflection caused by the radio wave reflecting structure. It is another object of the present invention to provide a structure for reducing a reflection obstruction of a building in which the effect of a radio wave absorbing wall is further enhanced to solve the problem of a radio wave reflection obstruction of the building.

[0010] Other objects and novel features of the present invention will be clarified in embodiments described later.

[0011]

In order to achieve the above object, a structure for reducing reflection obstruction of a building according to the present invention comprises a radio wave absorbing wall having a magnetic wave absorbing member and an outer wall which serves as a radio wave arrival surface of the building. And a radio wave reflecting structure exposed on the outer wall surface is disposed at a position rearward of the front surface of the magnetic radio wave absorbing member when viewed from a radio wave arrival direction.

In the structure for reducing reflection obstruction of a building according to the present invention, the radio wave absorbing wall is provided on one side of a portion of the radio wave reflecting structure parallel to an electric field direction of an incoming radio wave, and the other side is provided on the other side. It may be configured to be a radio wave transmitting surface.

As shown in FIG. 12 and FIG. 13, a ferrite electromagnetic wave absorber, which is a magnetic electromagnetic wave absorber using a ferrite tile as a magnetic electromagnetic wave absorbing member, transmits a magnetic wave to the back of the ferrite tile 1. The basic structure is a structure backed by a metal plate 2 serving as a reflector. The ferrite tiles 1 are arranged continuously in the magnetic field direction of the arriving radio wave, but the radio wave absorption characteristics are sufficiently maintained even if a gap is provided in the electric field direction. Has been clarified both theoretically and experimentally (Transactions of the Institute of Electronics and Communication Engineers, '79 / 8 VOL. J61-B No. 8, or JP-B-55-49798). The reason for this is that, generally speaking, if the gap is sufficiently small compared to the wavelength, the gap can be regarded as one surface in terms of radio waves.

Therefore, if there is a reflector having the same potential on the back surface of the ferrite, which is the design condition of the ferrite radio wave absorber, the operation as the radio wave absorber can be expected even if some gap is provided between the ferrites. In particular, in ferrite radio wave absorbers, ferrite as a magnetic radio wave absorbing member has a radio wave focusing effect, and even if there is a relatively large gap in the direction of the electric field, radio waves are focused on the ferrite part and the radio wave absorption characteristics are degraded. There is no. On the other hand, it is desired that the direction of the magnetic field be as continuous as possible. The reason is that the presence of the air gap in the direction of the magnetic field increases the magnetic resistance, and the generation of the demagnetizing field significantly deteriorates the magnetic characteristics. In this case, as a matter of course, it is required that the reflector on the back side of the ferrite necessary to constitute the ferrite electromagnetic wave absorber be continuous.

Focusing on the characteristics of ferrite which is such a magnetic wave absorbing member, if the ferrite wave absorber constituting the wave absorbing wall can sufficiently exhibit the characteristics, as a basic design condition of the ferrite wave absorber. Other than the configured reflector, a radio wave reflecting structure that exists independently of the radio wave absorbing wall but is sufficiently small as compared with the radio wave absorbing wall, for example, such as the metal window frame 11 in FIG. The idea is that even a radio wave reflecting structure that is located at the end of the radio wave absorption wall 10 and has one side that is open to radio waves (the glass surface 12 that is a radio wave transmitting surface) can be hidden in radio waves. , Examined the possibility.

As shown in FIG. 5, an exterior tile (granite) 23 having a thickness of 14 mm is disposed in front of a ferrite tile 21 having a thickness of 7.3 mm, and a concrete having a thickness of 12 mm is provided behind the ferrite tile 21. 25, and a radio wave reflecting plate (metal plate) 24 is arranged on the back surface thereof.
A prototype of a radio wave absorbing panel 20 having a practical structure of 900 mm in length and 900 mm in length is formed, and a gap 26 having a width of 20 mm is formed in the center of the radio wave absorbing panel 20 in a direction parallel to the electric field direction of the arriving radio wave. The metal plate is placed on the same plane as the front of the exterior tile (granite) 23 of the radio wave absorbing panel (position a), on the same plane as the front of the ferrite tile 21 (position b), and on the same plane as the back of the ferrite tile 21 (position c). ), And finally on the same plane as the radio wave reflecting surface of the radio wave reflecting plate 24 (position d),
The electromagnetic wave absorption characteristics when the panel was mounted at different positions in the thickness direction of the panel were measured. FIG. 6 shows the measurement results.

In the frequency characteristic of the return loss shown in FIG.
When a metal plate is mounted on the same surface as the front surface of the exterior tile 23 at the position a, this has the greatest effect on the radio wave absorption characteristics, and the apparent amount of radio wave absorption of the radio wave absorption panel is compared to the best value due to the influence of the reflection of the metal plate. As a result, the power deteriorates by about 10 dB. Similarly, the ferrite tile 21 which is the magnetic wave absorbing member at the position b
When a metal plate is mounted on the same surface as the front surface, the characteristics are not deteriorated as much as the position a, but it is still about 5 d compared to the best value.
It was confirmed that about B deteriorated. On the other hand, when metal plates are mounted at positions c and d on the same plane as the back surface of the ferrite tile 21 which is a magnetic wave absorbing member or on the same plane as the radio wave reflecting surface of the radio wave reflecting plate 24, the center frequency is slightly shifted. However, the radio wave absorption characteristic is 35dB as originally designed.
It was confirmed that the composition exhibited excellent characteristics. It should be noted that such a shift in the center frequency is within a range that can be sufficiently controlled by controlling the thickness of the ferrite tile according to the design principle of the ferrite electromagnetic wave absorber.

As a result, the radio wave focusing effect of ferrite as a magnetic wave absorbing member is such that even if a radio wave reflecting structure is present in a gap parallel to the direction of the electric field, the position is located behind the front surface of the ferrite, preferably the ferrite. If it is located on the same plane as the back of the building or behind it, it is well recognized. By using this effect, the electromagnetic wave absorption of the window frame etc., which has been a major obstacle to measures against radio wave reflection of buildings in the past. The structure that cannot be processed by the body etc. was concealed by radio waves, and the possibility of suppressing the reflection of radio waves from this structure was clarified.

[0019]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an embodiment of a structure for reducing a reflection obstruction of a building according to the present invention.

FIG. 1 shows an embodiment of a structure for reducing a reflection obstruction of a building according to the present invention, and FIG. 2 shows an example of a high-rise building to which the present invention is applied.

A high-rise building 30 as shown in FIG.
1 are arranged continuously in parallel with the direction of the electric field of the arriving radio wave and have a large area. Therefore, the aluminum sash constituting the window frame also extends in the direction of the electric field, and the radio wave absorbing wall 40 is attached to the outer wall surface other than the window 31. However, a window frame arrangement as shown in FIG. 1 is used for a building whose effect cannot be expected so much due to past experience. That is, in FIG. 1, the radio wave absorbing wall 40 includes an exterior material 43 such as an exterior tile that also serves to prevent a ferrite tile (ferrite plate) 41 as a magnetic electromagnetic wave absorbing member from falling.
Is placed on the front surface of the ferrite tile 41, a reinforcing bar 44 serving as a metal reflection mesh (radio wave reflector) is arranged behind the ferrite tile 41, and concrete 45 is cast on the back side of the ferrite tile 41 to integrate them. A window frame having a window glass 51 to be a radio wave transmitting surface is an aluminum sash 5
0. The aluminum sash horizontal portion 50A parallel to the electric field direction of the arriving radio wave of the aluminum sash 50 functions as a radio wave reflector, but at least this aluminum sash horizontal portion 50A is used as a ferrite tile 41 as a magnetic radio wave absorbing member of the radio wave absorbing wall 40. The radio wave absorbing wall 40 is attached to the structural body of the high-rise building so as to be located slightly behind the back.

As a result, the problem of radio wave reflection of the window frame is solved, the inherent characteristics of the radio wave absorbing wall are exhibited, and the reflection obstacle of the building can be solved.

In this case, the structure in which the window frame is mounted on the radio wave absorbing wall is in a state where the aluminum sash horizontal portions 50A of the window frame are mounted on the upper and lower ends of the radio wave absorbing wall 40.
The evaluation of the radio wave absorption characteristics was performed using the time domain method in such a state. The result is compared with the case without the aluminum sash, and is shown in the graph of the frequency characteristic of the return loss in FIG. Curve C in FIG. 3 shows the case with the window frame according to the embodiment of the present invention, and curve D shows the case without the window frame. However, the vertical dimension of the radio wave absorbing wall 40 is 4000 mm,
The horizontal dimension was 3200 mm, and the vertical width of the aluminum sash horizontal portion 50A was 100 mm.

From FIG. 3, it can be seen that according to the embodiment of the present invention, the return loss almost equal to that without the window frame is obtained.

Although the aluminum sash 50 has not only a horizontal portion but also a vertical portion, the TV broadcast radio wave is a horizontally polarized wave, and the vertical portion of the aluminum sash 50 is perpendicular to the electric field. Therefore, the function as a radio wave reflector is small, and no special consideration is required.

In the above-described embodiment, the aluminum sash horizontal portion 50A serving as a radio wave reflecting structure for incoming radio waves is positioned slightly behind the back surface of the ferrite tile 41 as the magnetic radio wave absorbing member of the radio wave absorbing wall 40. However, from the description of FIG. 5 described above, it is possible to prevent the deterioration of the characteristics of the radio wave absorbing wall to some extent if the radio wave reflecting structure is disposed at a position behind the front surface of the magnetic radio wave absorbing member when viewed from the radio wave arrival direction. it is obvious.

Although the embodiments of the present invention have been described above, it is obvious to those skilled in the art that the present invention is not limited to the embodiments and various modifications and changes can be made within the scope of the claims. There will be.

[0028]

As described above, according to the structure for reducing the reflection obstruction of a building according to the present invention, since there are many window frames or a gondola rail or the like, the structure of the building that could not be sufficiently solved by the radio wave absorbing wall alone is not sufficient. I think that it will be a great way to contribute to the design of high-rise buildings in the future, opening a new way for measures against radio wave reflection.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an embodiment of a structure for reducing reflection obstruction of a building according to the present invention.

FIG. 2 shows a high-rise building 1 to which the embodiment of the present invention is applied.
It is a front view showing an example.

FIG. 3 is a graph showing a frequency characteristic of a return loss evaluated by comparing the effect of reducing reflection impairment according to the embodiment of the present invention with a case without a window frame.

FIG. 4 is a front view showing an example of a window frame structure of a continuous window in a building having a radio wave absorbing wall on an outer wall surface.

FIG. 5 is a structural diagram for examining the influence on the reflection characteristics due to the arrangement of a metal plate arranged in a gap parallel to the electric field direction of the arriving radio wave of the radio wave absorption panel.

6 is a graph showing frequency characteristics of return loss corresponding to a metal plate arrangement in which the position is changed in the thickness direction of the radio wave absorption panel of FIG. 5;

FIG. 7 is a perspective view showing a conventional example of a radio wave absorbing wall having a structure to be fixed with an exterior tile with special feet.

FIG. 8 is a front view showing a structure in which a metal reflector independent of the radio wave absorbing panel is arranged between the radio wave absorbing panels.

9 is an enlarged front view showing a circle P in FIG. 8 in an enlarged manner.

FIG. 10 is an enlarged side sectional view of the same.

FIG. 11 is a graph showing a frequency characteristic of return loss comparing a structure in which a metal reflector independent of the radio wave absorbing panel is arranged between the radio wave absorbing panels as shown in FIGS. 8 to 10 and a case where there is no metal reflector; is there.

FIG. 12 is a front view showing a conventional example which is a basic example of a radio wave absorbing wall in which ferrites are arranged continuously in a magnetic field direction and discontinuous in an electric field direction.

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

[Explanation of symbols]

 1,21,41 Ferrite tile 2 Metal plate 3,23 Exterior tile 4,44 Reinforcement 5,25,45 Concrete 10A, 10B, 20 Radio wave absorption panel 11 Rail-shaped metal reflector 24 Radio wave reflector 30 High-rise building 31 Window 40 Electric wave absorption wall 43 Exterior material 50 Aluminum sash 50A Aluminum sash horizontal part

Claims (2)

[Claims] 1. A radio wave absorbing wall having a magnetic wave absorbing member is provided on an outer wall surface serving as a radio wave arrival surface of a building, and a radio wave reflecting structure exposed on the outer wall surface is located at a position higher than the front surface of the magnetic wave absorbing member. A structure for reducing reflection obstruction of a building, wherein the structure is disposed at a rear position as viewed from a radio wave arrival direction. 2. The radio wave reflecting structure according to claim 1, wherein the radio wave absorbing wall is provided on one side of a portion of the radio wave reflecting structure parallel to an electric field direction of an incoming radio wave, and the other side is a radio wave transmitting surface. A structure to reduce the reflection obstacles in buildings.