Structure and radio wave suppression method using the same

Abstract

To provide a structure that can easily adjust interference and a radio wave suppression method using the same. [Solution] One embodiment of the structure is a radio wave shielding layer that is arranged to cover the perimeter of a radio station and shields radio waves radiated from the radio station, and comprises a radio wave shielding layer having at least one opening.

Description

Technical Field

[0001] The present disclosure relates to a structure and a radio wave suppression method using the same.

Background Art

[0002] Local 5G is a technology for companies and local governments other than telecommunications carriers to build a dedicated high-speed wireless communication network within a specific area or facility. Different from the public 5G network constructed by conventional telecommunications carriers, the local 5G network is used only in limited locations such as specific factories, warehouses, event venues, and public facilities. Since it is a network used in a limited area, it is expected that in local 5G, devices such as dedicated IoT devices, sensors, and robots can be used in a high-speed and stable communication environment.

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] With the spread of local 5G, when a large number of wireless stations exist in the same area, it is assumed that the wireless stations will interfere with each other. When radio wave leakage occurs to adjacent other people's land, the communication quality on one's own land and other people's land deteriorates. In order to suppress such interference and radio wave leakage, interference adjustment is required so that there is no influence of interference among operators. Usually, for interference adjustment, methods such as adjusting the position, direction, and output of antennas are used. On the other hand, in these methods for interference adjustment, there is a risk that the operation will become complicated when local 5G spreads, such as an increase in the adjustment work by operators.

[0005] This disclosure provides a structure that can easily perform interference adjustment and a radio wave suppression method using the same. [Means for solving the problem]

[0006] One embodiment of the structure is a radio wave shielding layer that is arranged to surround a radio station and shields radio waves radiated from the radio station, and comprises a radio wave shielding layer having at least one opening. [Effects of the Invention]

[0007] This disclosure provides a structure that can easily perform interference adjustment and a radio wave suppression method using the same. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 shows an example of a wireless communication system according to an embodiment. [Figure 2] Figure 2 shows the configuration of an example structure. [Figure 3] Figure 3 is a schematic cross-sectional view of an example of a radio wave absorbing sheet. [Figure 4] Figure 4 shows the structure configuration of an example of modified example 1. [Figure 5] Figure 5 shows the structure configuration of an example of modified example 2. [Figure 6] Figure 6 shows the structure of a structure provided with multiple cylindrical openings in modified example 2. [Figure 7] Figure 7 shows the structure configuration of an example of modified example 3. [Figure 8] Figure 8 shows the structure configuration of an example of modified example 4. [Figure 9] Figure 9 shows the structure configuration of an example of modified example 5. [Figure 10A] Figure 10A is a front view of the blind mechanism in the open state, as a modified example 6. [Figure 10B] Figure 10B is a perspective view of the blind mechanism in the open state, as a modified example 6. [Figure 10C] Figure 10C is a front view of the blind mechanism in the closed state, as modified example 6. [Figure 10D] Figure 10D is a perspective view of the blind mechanism in the closed state, as modification 6. [Figure 11] Figure 11 shows the configuration of a sliding door mechanism as a modified example 6. [Figure 12] Figure 12 shows the structure of the modified example 7. [Figure 13A] Figure 13A shows the structure configuration of the first example of Modification 8. [Figure 13B] Figure 13B shows the structure configuration of the second example of Modification 8. [Figure 14A] Figure 14A shows the structure configuration of the first example of Modification 9. [Figure 14B] Figure 14B shows the structure configuration of the second example of Modification 9. [Modes for carrying out the invention]

[0009] Embodiments will be described below with reference to the drawings. However, the present invention is not limited by these embodiments. In the drawings, identical parts are denoted by the same reference numeral. When there are multiple components having the same or similar function, different subscripts may be used for the same reference numeral. Furthermore, if it is not necessary to distinguish between these multiple components, the subscript may be omitted. The positions, sizes, shapes, and ranges of the components shown in the drawings may not represent their actual positions, sizes, shapes, and ranges in order to facilitate understanding of the invention. Therefore, this disclosure is not necessarily limited to the positions, sizes, shapes, and ranges disclosed in the drawings.

[0010] FIG. 1 is a diagram showing an example of a wireless communication system according to an embodiment. In FIG. 1, two wireless communication systems 100a and 100b are shown. The wireless communication systems 100a and 100b are systems compliant with, for example, 5G standards. Here, in one example, the wireless communication system 100a is a wireless communication system constructed on its own land, and the wireless communication system 100b is a wireless communication system constructed on another's land.

[0011] The wireless communication systems 100a and 100b each include a radio station 1. The radio station 1 is connected to a communication network (not shown). The radio station 1 wirelessly communicates with a terminal device 200 that may be present within a coverage area 300. The terminal device 200 is a terminal device having a wireless communication function such as a personal computer or a smartphone. The radio station 1 is installed, for example, outdoors in a form supported by a pillar 12. In addition to the coverage area 300, an adjustment target area 400 is set for the radio station 1. The adjustment target area 400 is an area where there is a possibility of interference with other wireless communication systems. Usually, the adjustment target area 400 is wider than the coverage area 300.

[0012] Here, in the example of FIG. 1, the coverage areas 300 and the adjustment target areas 400 of the wireless communication system 100a and the wireless communication system 100b overlap. Therefore, the wireless communication system 100a and the wireless communication system 100b may interfere with each other.

[0013] In the embodiment, a structure for shielding radio waves is installed for the radio station 1 of the wireless communication system 100a on its own land, and by suppressing the radiation of radio waves in an unwanted direction from the radio station 1, interference with the wireless communication system on another's land is suppressed.

[0014] FIG. 2 is a diagram showing the configuration of an example structure. As shown in FIG. 2, the structure 2 is configured as, for example, a box-shaped structure made of six plate-like panels. The radio station 1 is housed inside the structure 2. The material of the plate-like panel can be any material such as synthetic resin like plastic, gypsum board, metal such as steel and aluminum, or wood, etc.

[0015] A radio wave absorbing sheet is attached to the surface of a plate-shaped panel that constitutes the inner wall surface of structure 2. Figure 3 is a schematic cross-sectional view showing the configuration of an example of a radio wave absorbing sheet. The radio wave absorbing sheet 3 has, for example, a metal plate layer 32 and a radio wave absorber layer 31 attached to the metal plate layer 32. The radio wave absorbing sheet 3 can function as an example of a radio wave shielding layer that shields radio waves radiated to the outside of structure 2.

[0016] The radio wave absorbing layer 31 is a layer composed of a radio wave absorbing material that has the property of absorbing radio waves. The type of radio wave absorbing material is not particularly limited. Radio wave absorbing materials are generally broadly classified into three types: resistive absorbing materials, dielectric absorbing materials, and magnetic absorbing materials. Resistive absorbing materials include conductors such as carbon resistors, resistance wires, and resistive coatings with deposited metal oxides. When radio waves are irradiated onto a resistive absorbing material, a high-frequency current flows through the conductor of the resistive absorbing material. Joule heat is generated when a high-frequency current flows through the conductor. In this way, in a resistive absorbing material, the electromagnetic energy from radio waves is converted into thermal energy and consumed. Dielectric absorbing materials include dielectrics such as carbon rubber and carbon-containing foam, and attenuate radio waves through dielectric loss. Magnetic absorbing materials include magnetic materials such as ferrite sintered bodies and rubber ferrite, and attenuate radio waves through magnetic loss. The radio wave absorbing layer 31 may be composed of one layer of radio wave absorbing material, or it may be composed of two or more layers of radio wave absorbing material.

[0017] Here, it is preferable that the radio wave absorbing layer 31 has a reflection attenuation of 10 dB or more for both the field polarization perpendicular to the incident plane (TE wave) and the magnetic field polarization perpendicular to the incident plane (TM wave) of incident radio waves in the desired frequency band, within the range of incident angle from 0 degrees to 80 degrees.

[0018] Furthermore, a functional layer may be laminated on the surface of the radio wave absorber layer 31. The functional layer is a layer that adds at least one of the following properties: degradation prevention, design, protection / scratch resistance, waterproofing, gas / water vapor barrier properties, flame retardancy, non-combustibility, self-extinguishing properties, weather resistance, antifouling, antibacterial / antiviral properties, chemical resistance, deodorizing properties, adhesiveness / bonding properties, etc. Multiple functions may be added by laminating multiple functional layers. Instead of laminating a functional layer on the radio wave absorber layer 31, the functional layer may be added to the radio wave absorber layer 31, or a material that gives functionality to the radio wave absorber may be mixed in. Alternatively, the radio wave absorber layer 31 may be coated or otherwise processed using a material with functionality. Depending on the purpose of use, the functional layer may be formed on the entire surface of the radio wave absorber layer 31, or it may be formed on only a part of any of the layers.

[0019] The metal plate layer 32 is a layer of metal material for reinforcing the radio wave absorber layer 31. The radio wave shielding sheet 3 is attached to the plate-shaped panel structure 2 by means of adhesive or other methods, thereby attaching the metal plate layer 32 to the inner wall surface of the plate-shaped panel structure 2.

[0020] Here, instead of the radio wave absorbing sheet 3, the radio wave absorbing layer 31 may be made into a flexible sheet or film, and only this radio wave absorbing layer 31 may be attached to the inner wall surface of the structure 2. Such a sheet or film-like radio wave absorbing layer 31 is lightweight and easy to process and install.

[0021] Alternatively, instead of the radio wave absorbing layer 31, a paint with radio wave absorbing properties may be applied to the inner wall surface of the structure 2. Furthermore, the plate-shaped panels of the structure 2 may be formed from a radio wave absorbing material.

[0022] Now, let's return to the explanation of Figure 2. An opening 22 is provided on the side of structure 2 in the desired direction from which radio waves from radio station 1 are to be emitted. It is desirable that the opening 22 be located at a height opposite the front of the antenna cover (hereinafter referred to as the radome) of radio station 1, which is the radio wave emitting part of radio station 1, that is, the surface from which the radio waves of the main lobe are emitted. The shape of the opening 22 may be any shape, such as a polygon, circle, or ellipse. However, it is preferable that the area of ​​the opening 22 is greater than or equal to the area of ​​the front of the radome of radio station 1.

[0023] The opening 22 can be formed by removing the plate-shaped panel in the portion corresponding to the opening 22, as shown in Figure 2. Alternatively, if the plate-shaped panel is made of a material with low radio wave absorption performance, the opening 22 can also be formed by not attaching the radio wave absorbing sheet 3 to the portion corresponding to the opening 22.

[0024] In the structure 2 shown in Figure 2, radio waves emitted from the radome of the radio station 1 in directions other than the desired direction are absorbed by the radio wave absorbing sheet 3 attached to the plate-shaped panel of the structure 2, and radio waves emitted from the radome of the radio station 1 in the desired direction are emitted to the outside of the structure 2 through the opening 22. In this way, by suppressing the emission of radio waves from the radio station 1 in undesirable directions, interference with wireless communication systems on other people's land can be suppressed. Thus, in this embodiment, interference adjustment can be performed very simply.

[0025] Although not shown in Figure 2, structure 2 may have an opening for mounting a device that acquires GPS signals for radio station 1 to establish synchronization with other radio stations. This opening for mounting the device may be formed, for example, in the ceiling portion of structure 2.

[0026] Furthermore, Figure 2 shows that structure 2 is constructed by forming a box shape from six plate-like panels. However, if, for example, radio station 1 is used outdoors, it is generally considered that there are no radio wave interference problems with the ground. In such cases, structure 2 may be constructed from five plate-like panels, excluding the bottom surface.

[0027] (Variation 1) The following describes modifications of the embodiment. Figure 2 shows one opening 22. In contrast, as shown in Figure 4, the structure 2 may have two or more openings 22, each formed on a different surface of the structure 2.

[0028] Because there are two or more openings 22, the direction of radio waves radiated outside the structure 2 can be changed simply by changing the orientation of the radome to the position of another opening 22. Therefore, it is possible to adjust the coverage area and received power to suit the surrounding environment, and it is expected that more flexible interference adjustment will be possible.

[0029] (Modification 2) In this embodiment, an example is shown in which the opening 22 is directly formed on the surface of the structure 2. In contrast, the opening may be a cylindrical opening 23 that protrudes toward the direction of radio wave radiation, as shown in Figure 5. The opening 23 has an open end. The shape of the opening 23 may be a rectangular prism, a cylinder, a truncated pyramid, or a truncated cone. Furthermore, a radio wave absorbing sheet 3 may be attached to the inner wall surface of the opening 23.

[0030] The opening 23 can be formed by attaching a further cylindrical opening to the opening 22 in Figure 2. Alternatively, the opening 23 may be molded integrally with the plate-like panel.

[0031] By creating a cylindrical opening 23, the structure 2 can emit radio waves with higher directivity. In this way, the emission of radio waves from the radio station 1 in undesirable directions is suppressed, thereby reducing interference with wireless communication systems on other people's land.

[0032] Here, as shown in Figure 6, the structure 2 may have two or more openings 23 formed on different surfaces of the structure 2. By providing two or more openings 23, it is possible to adjust the coverage area and received power to suit the surrounding environment, similar to Modification 1, and it is expected that more flexible interference adjustment will be possible.

[0033] (Variation 3) In the embodiments and modifications described above, structure 2 is shown as a structure that houses the radio station 1 together with the support column 12. Here, structure 2 can be miniaturized by positioning it closer to the radio station 1 than shown in Figure 2. Alternatively, structure 2 may be a structure that covers only the radome 11 of the radio station 1, as shown in Figure 7. A structure like that in Figure 7 allows for further miniaturization of structure 2.

[0034] (Modification 4) In the embodiments and modifications described above, structure 2 is shown as a structure that houses the radio station 1. In contrast, structure 2 may be a radio wave absorber 21 that is attached, for example, to the surface of the radome 11 of the radio station 1, as shown in Figure 8. The radio wave absorber 21 may have the same configuration as the radio wave absorbing sheet 3 shown in Figure 3, or it may be a structure consisting only of a flexible sheet-like or film-like radio wave absorber layer 31, or a paint with radio wave absorbing properties may be applied to the surface of the radome 11. With a structure like that shown in Figure 8, further miniaturization of structure 2 can be achieved.

[0035] (Variation 5) In the example shown in Figure 2, the structure 2 is a rectangular box shape. In contrast, as shown in Figure 9, the structure 2 may have an inclination of angle θ at the top of the surface where the opening 22 is provided when viewed in cross-section. By having an inclination of angle θ at the top of the opening 22, diffraction of radio waves at the top can be suppressed. As a result, the structure 2 can be configured not to cover the entire perimeter of the radome 11 of the radio station 1. Therefore, the amount of plate-like panels required to form the structure 2 is reduced, and the structure 2 can be installed easily.

[0036] Here, the angle θ is preferably between 45° and 90° in order to more effectively suppress the diffraction of radio waves in the upper part of the device. By adjusting the angle θ according to the surrounding environment, it is possible to adjust the coverage area and received power according to the surrounding environment, and it is expected that more flexible interference adjustment will be possible.

[0037] (Experimental variation 6) In the embodiments and modifications described above, the opening 22 or opening 23 is always open, and its opening ratio is constant. In contrast, an adjustment mechanism may be provided for adjusting the opening ratio of the opening 22 or opening 23.

[0038] Figures 10A-10D illustrate a blind mechanism as a first example of an adjustment mechanism for adjusting the opening ratio of opening 22 or opening 23. Here, Figure 10A is a front view of the blind mechanism 24 in the open state. Figure 10B is a perspective view of the blind mechanism in the open state. Figure 10C is a front view of the blind mechanism 24 in the closed state. Figure 10D is a perspective view of the blind mechanism 24 in the closed state. The blind mechanism 24 is provided on the front of opening 22 or opening 23.

[0039] The blind mechanism 24 is composed of numerous feather-shaped slats formed by the radio wave absorber 21. By changing the angle of the slats, the aperture ratio of the opening 22 or opening 23 changes. By changing the aperture ratio of the opening 22 or opening 23, the direction and intensity of radio waves radiated to the outside of the structure 2 also change. By changing the aperture ratio of the opening 22 or opening 23 with the blind mechanism 24, it is possible to adjust the coverage area and received power to suit the surrounding environment, and it is expected that more flexible interference adjustment will be possible.

[0040] Figure 11 shows the configuration of a sliding door mechanism as a second example of an adjustment mechanism for adjusting the opening ratio of opening 22 or opening 23. In Figure 11, the opening is shown as opening 23, but it goes without saying that the opening may also be opening 22.

[0041] The sliding door mechanism 25 is composed of, for example, two plate-like members and is movable in two directions: one in a direction that opens the opening 23 and another in a direction that shields the opening 23. The spacing between the slits formed by the two plate-like members changes the aperture ratio of the opening 23. As the aperture ratio of the opening 22 or the opening 23 changes, the direction and intensity of the radio waves radiated to the outside of the structure 2 also change. By changing the aperture ratio of the opening 23 with the sliding door mechanism 25, it is possible to adjust the coverage area and received power to suit the surrounding environment, and it is expected that more flexible interference adjustment will be possible.

[0042] In the modified example, a blind mechanism 24 and a sliding door mechanism 25 are provided as examples. However, the adjustment mechanism for adjusting the opening ratio of the opening 22 or opening 23 is not limited to the blind mechanism 24 and the sliding door mechanism 25. For example, the mechanism for adjusting the opening ratio of the opening 22 or opening 23 may be a movable louver mechanism or the like.

[0043] (Example 7) Instead of providing an adjustment mechanism to adjust the aperture ratio of aperture 22 or aperture 23, a transparent metasurface 26 may be provided in aperture 22, as shown in Figure 12. A metasurface is a type of artificial medium (metamaterial) that achieves arbitrary dielectric constant and permeability by periodically arranging structures smaller than the wavelength, and is an artificial surface composed of structures arranged periodically in two dimensions. By electrically controlling the directivity and absorption rate of radio waves in the metasurface 26, the direction and intensity of radio waves radiated from aperture 22 to the outside of structure 2 can be changed. In this way, by providing a transparent metasurface 26 in aperture 22, it is possible to adjust the coverage area and received power to suit the surrounding environment, and it is expected that more flexible interference adjustment will be performed. Here, although the aperture is shown as aperture 22 in Figure 12, it goes without saying that the aperture may also be aperture 23.

[0044] (Variation 8) The end of the opening 22 may have a structure that is folded back and inclined toward the radio station 1 when viewed in cross-section, as shown in Figure 13A. Having a folded structure in the opening 22 can suppress the diffraction of radio waves at the end of the opening 22.

[0045] Furthermore, the folded structure may not be a planar folded structure as shown in Figure 13A, but a curved folded structure as shown in Figure 13B. By using a curved folded structure, the diffraction of radio waves can be suppressed more effectively.

[0046] Here, in Figures 13A and 13B, the opening is shown as opening 22, but it goes without saying that the opening could also be opening 23.

[0047] (Extreme variation 9) In the embodiments and modifications described above, the structure 2 is shown as being configured to surround the radio station 1. Depending on the required degree of interference adjustment, the structure 2 does not have to be configured to surround the radio station 1. Figures 14A and 14B are top views showing the relationship between the structure 2 and the radio station 1. In other words, if strict interference adjustment is not required, the structure 2 may be a structure consisting of three plate-like panels that shield the three sides other than the desired direction, as shown in Figure 14A. Alternatively, the structure 2 may be a structure consisting of two plate-like panels arranged diagonally that shield the three sides other than the desired direction, as shown in Figure 14B. In the case of the structure 2 as shown in Figures 14A and 14B, the desired direction is open, so the opening 22 or opening 23 is unnecessary.

[0048] (Other variations) The present invention is not limited to the embodiments described above, and can be modified in various ways during implementation without departing from its essence. Furthermore, each embodiment may be combined as appropriate, and in that case, the combined effects can be obtained. Moreover, the above embodiments include various inventions, and various inventions can be extracted by selecting combinations from the multiple constituent elements disclosed. For example, if the problem can be solved and effects obtained even if some constituent elements are deleted from all the constituent elements shown in the embodiment, then the configuration with these deleted constituent elements can be extracted as an invention. [Explanation of symbols]

[0049] 1 Radio station, 2 Structure, 3 Radio wave absorbing sheet, 11 Radome, 12 Support column, 21 Radio wave absorber, 22 Opening, 23 Opening, 24 Blind mechanism, 25 Sliding door mechanism, 26 Metasurface, 31 Radio wave absorber layer, 32 Metal plate layer, 100a, 100b Wireless communication system, 200 Terminal equipment, 300 Coverage area, 400 Area to be adjusted.

Claims

1. A structure comprising a radio wave shielding layer arranged to surround a radio station and shielding radio waves radiated from the radio station, the radio wave shielding layer having at least one opening.

2. The opening is formed at a height opposite to the radome of the radio station. The structure according to claim 1.

3. A radio wave absorbing sheet is attached to the side of the radio wave shielding layer facing the radio station. The structure according to claim 1.

4. Multiple openings are provided. The structure according to claim 1.

5. The upper part of the radio wave shielding layer, in which the opening is provided, is inclined toward the side of the radio station. The structure according to claim 1.

6. The aforementioned opening is a cylindrical opening that protrudes in the direction of radiation of the radio waves. The structure according to claim 1.

7. The radio wave shielding layer is formed to accommodate the radome of the radio station. The structure according to claim 1.

8. The aforementioned radio wave shielding layer is formed to be in close contact with the radome of the radio station. The structure according to claim 1.

9. The structure according to claim 1, further comprising an adjustment mechanism provided in the opening for adjusting the opening ratio of the opening.

10. The structure according to claim 1, further comprising a metasurface provided in the opening, which changes the directivity and absorption rate of the radio waves radiated from the opening.

11. The end of the opening has a folded structure that is inclined toward the radio station. The structure according to claim 1.

12. The radio wave shielding layer further has openings formed therein for mounting a device for the radio station to acquire GPS signals. The structure according to claim 1.

13. At least a radio wave shielding layer is placed around the radio station to block radio waves radiated from the radio station in undesirable directions. Radio wave suppression method.

14. The aforementioned radio wave shielding layer is arranged to cover the perimeter of the radio station and shields radio waves radiated from the radio station, and is provided with at least one opening. The radio wave suppression method according to claim 13.

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