Wireless transmission system

Abstract

The present application relates to a wireless transmission system that improves wave propagation of mobile communication within a production facility such as a factory, a factory equipment, or the like. The wireless transmission system is provided with: a base station that transmits and receives a wave of a desired frequency band selected from a frequency band of 1 GHz to 170 GHz; and an electromagnetic wave reflection device that is disposed along at least a part of a production line on which a production machine that transmits and receives the wave is disposed, and has a reflection surface that reflects the wave.

Description

Technical Field

[0001] This invention relates to wireless transmission systems. Background Technology

[0002] The Industrial Internet of Things (IIoT), which automates manufacturing processes and introduces advanced production and process management, as well as preventative maintenance, to the manufacturing site, is developing. In the IIoT, "smart factories" connect devices, machines, and management systems within the factory to the cloud and edge AI (Artificial Intelligence), thereby improving manufacturing efficiency. There is anticipation of introducing high-speed, high-capacity, low-latency mobile communication technologies like 5G, capable of simultaneous multi-connection, into the communication networks of the IIoT that handle massive amounts of data. In addition to the inherent mobility and flexibility of mobile communication technologies, the low latency of 5G is also suitable for the IIoT.

[0003] A joint structure for a light-transmitting electromagnetic wave shielding panel used in buildings such as smart buildings has been proposed (for example, see Patent Document 1).

[0004] Patent Document 1: Japanese Patent No. 4892207

[0005] The communication environment within production facilities such as factories and factory equipment differs from that of public mobile communications. Within production facilities, various mechanical structures and objects obstruct the propagation of communication waves, making it difficult to achieve high communication quality. Summary of the Invention

[0006] The purpose of this invention is to provide a technology for improving the propagation of radio waves in mobile communications within production facilities.

[0007] In one embodiment of this disclosure, the wireless transmission system comprises:

[0008] A base station transmits and receives radio waves in a desired frequency band selected from the 1GHz to 170GHz frequency band; and

[0009] An electromagnetic wave reflecting device is disposed along at least a portion of a production line equipped with production machines that transmit and receive the aforementioned electromagnetic waves, and has a reflecting surface that reflects the aforementioned electromagnetic waves.

[0010] The electromagnetic wave reflection device with the above structure improves the propagation of electromagnetic waves for mobile communication in production facilities such as factories and factory equipment. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of a production line within a factory that can utilize the present disclosure.

[0012] Figure 2 This is a plan view of a wireless transmission system using an electromagnetic wave reflection device according to the implementation method.

[0013] Figure 3A It is a diagram illustrating reflection at the same angle of incidence as the angle of incidence.

[0014] Figure 3B It is a diagram illustrating reflection at a reflection angle different from the angle of incidence.

[0015] Figure 3C It is a diagram illustrating diffusion in multiple directions.

[0016] Figure 4 This is a diagram illustrating the basic concept of an electromagnetic wave reflecting device according to an implementation method.

[0017] Figure 5A This is a diagram showing a modified example of an electromagnetic wave reflecting device.

[0018] Figure 5B This is a diagram showing a modified example of an electromagnetic wave reflecting device.

[0019] Figure 5C This is a diagram showing a modified example of an electromagnetic wave reflecting device.

[0020] Figure 5D This is a diagram showing a modified example of an electromagnetic wave reflecting device.

[0021] Figure 6A This is an example of the composition of a reflective surface.

[0022] Figure 6B This is another example of a reflective surface.

[0023] Figure 6C This is another example of a reflective surface.

[0024] Figure 6D This is another example of a reflective surface.

[0025] Figure 7 This diagram shows an example of connecting an electromagnetic wave reflecting device.

[0026] Figure 8 This is a schematic diagram of the connection part of the support body.

[0027] Figure 9A This is a diagram illustrating an example of edge treatment for a panel.

[0028] Figure 9B This is another example of how the edges of a panel are handled.

[0029] Figure 10A This is a diagram showing an example of the structure of a connecting part.

[0030] Figure 10B This is a diagram showing another example of the configuration of the connecting part.

[0031] Figure 10C This is a diagram showing another example of the configuration of the connecting part.

[0032] Figure 10D This is a diagram showing another example of the configuration of the connecting part.

[0033] Figure 10E This is a diagram showing another example of the configuration of the connecting part.

[0034] Figure 10F This is a diagram representing a typical connection structure as a reference example.

[0035] Figure 11A This is a diagram illustrating the connections between multiple panels.

[0036] Figure 11B This is a diagram showing the state of the electromagnetic wave reflecting device before it was connected.

[0037] Figure 11C This is a diagram showing the state of the connected electromagnetic wave reflecting device.

[0038] Figure 12 This is a diagram illustrating an enhanced example of a connected electromagnetic wave reflection device.

[0039] Figure 13 This is a diagram illustrating an example of a fixed mechanism.

[0040] Figure 14 This is a diagram illustrating the dimensions of the meta-reflector.

[0041] Figure 15 It is a diagram that studies the area size corresponding to the frequency of action and the positional relationship between sending and receiving.

[0042] Figure 16A It is a diagram illustrating the configuration relationships of a wireless transmission system.

[0043] Figure 16B It is a diagram illustrating the configuration relationships of a wireless transmission system.

[0044] Figure 17A This is a graph representing the baseline robustness of reflection mode 1.

[0045] Figure 17B This is a graph representing the baseline robustness of reflection mode 2.

[0046] Figure 18 This is a diagram illustrating the quantitative method for benchmark robustness.

[0047] Figure 19A This is a diagram showing the phase transition changes in reflection mode 1.

[0048] Figure 19B This is a diagram showing the phase transition changes in reflection mode 2. Detailed Implementation

[0049] <Overall picture of the system>

[0050] Figure 1 This is a schematic diagram of a production line within a factory that can utilize the present disclosure. A production line is a ribbon-like production site that configures equipment, machines, etc., used for assembly and production into a series of processes. In the Industrial Internet of Things (IIoT), by connecting industrial devices, machines, management systems, etc., used in the production line to the network, production efficiency is improved and on-site safety is ensured.

[0051] Base stations BS1 and BS2 are configured to connect the machines on the production line to the network. Machines M1 and M2 used in the production line each have wireless communication units WT1 and WT2, respectively, which communicate with at least one of the base stations BS1 and BS2 and are connected to the network.

[0052] To enable wireless connectivity between machines on the production line and the network, base stations BS1 and BS2 (hereinafter, appropriately referred to collectively as "BS") provide a horizontally elongated rectangular service area. In the technical specification (TS22.104) of 3GPP (3rd Generation Partnership Project), a standardization body for mobile communications, a service area with an aspect ratio of 3 to 5 is specified as a system requirement. For example, the area size for a use case referred to as "Motion Control" is specified as 50m × 10m × 10m in length × width × height.

[0053] To cover the production line within the service area provided by base stations BS1 and BS2, and to enable network connectivity for machines M1 and M2 within the production line, base stations BS1 and BS2 are positioned at the ends of the production line along its length, which is effective in terms of coverage. To improve communication quality and coverage, base stations BS1 and BS2 can also coordinate and cooperate. Details of the configuration relationship between base stations BS and the production line will be described later.

[0054] Figure 2This is a plan view of a wireless transmission system 1 using the electromagnetic wave reflecting device 10 of the embodiment. The wireless transmission system 1 includes: a production line 3, equipped with production machines capable of receiving and transmitting electromagnetic waves; a base station BS for wireless communication with the machines on the production line 3; and an electromagnetic wave reflecting device 10 disposed along the production line 3. The electromagnetic wave reflecting device 10 has a reflecting surface 105 for reflecting electromagnetic waves. The surface of the production line is designated as the XY plane, and the vertical direction perpendicular to the XY plane is designated as the Z direction.

[0055] The machines within production line 3 include all production-related machinery such as sensors, actuators, and other micro-devices, assembly units, manufacturing equipment, and management systems. The machines used in production line 3 are not limited to fixed devices or machinery; they can also be machines that move freely within production line 3.

[0056] Base station BS and machines M1 and M2 with wireless communication capabilities (see reference) Figure 1 For example, transmitting and receiving radio waves in a specific frequency band within the range of 1GHz to 170GHz. Production lines and surrounding structures (such as pipes and tubes) are mostly made of metal, thus reflecting and blocking radio waves. Furthermore, high-frequency radio waves, such as those in the millimeter wave band, have strong straight-line propagation properties and less diffraction, making them difficult to reach. For machines located in the central part of production line 3, reflections from surrounding machines and processed metal products become obstacles, resulting in a deteriorated communication environment.

[0057] If multiple base stations (BSs) are configured along the length of the production line 3, communication quality can be maintained, but this hinders the efficient use of workspace and increases equipment costs. In the wireless transmission system 1, an electromagnetic wave reflecting device 10 is configured along the length of the production line 3, and base stations (BSs) are configured at the ends of the production line 3. The electromagnetic wave reflecting device 10 reduces the number of base stations (BSs) installed in the production facility, improving the wireless communication environment between the base stations (BSs) and the machines within the production line 3.

[0058] The electromagnetic wave reflecting device 10 may also be arranged approximately parallel to the long axis of the production line 3, relative to at least a portion of the production line 3. "Approximately parallel" means that the electromagnetic wave reflecting device 10 does not need to be arranged strictly parallel to the long axis of the production line 3. Within the range for effective transmission and reception of radio waves between the base station BS and the machines in the production line 3, the electromagnetic wave reflecting device 10 may also be slightly tilted relative to the long axis of the production line 3.

[0059] The electromagnetic wave reflecting device 10 reflects electromagnetic waves in the 1GHz to 170GHz frequency band via a reflecting surface 105. The reflecting surface 105 is formed by at least one of a standard reflector 101 providing normal reflection with an incident angle equal to the reflection angle, and a metasurface 102, an artificial surface having reflection characteristics that control the incident electromagnetic waves. A "metasurface" refers to a type of "metasurface" of an artificial surface that controls the transmission or reflection characteristics of the incident electromagnetic waves. In the metasurface, multiple scatterers sufficiently small compared to the wavelength are arranged, and by controlling the reflection phase distribution and amplitude distribution, electromagnetic waves are reflected in a predetermined direction other than the direction of normal reflection. Through the metasurface 102, in addition to reflection in directions other than normal reflection, diffusion with a predetermined angular distribution and wavefront formation can also be achieved.

[0060] Figures 3A-3C This indicates the mode of reflection at the reflecting surface 105 of the electromagnetic wave reflecting device 10. Figure 3A In the process, electromagnetic waves incident on standard reflector 101 are reflected at a reflection angle θref that is the same as the incident angle θin.

[0061] exist Figure 3B In this process, electromagnetic waves incident on the metareflector 102a are reflected at a reflection angle θref that is different from the incident angle θin. The absolute value of the difference between the reflection angle θref based on the metareflector 102a and the reflection angle based on normal reflection can also be called the anomalous angle θabn. As described above, by placing a metal patch or the like, which is sufficiently small in size than the wavelength used, on the surface of the metareflector 102a, surface impedance is formed, thereby controlling the reflection phase distribution and reflecting the incident electromagnetic waves in the desired direction. Details will be described later, but in the case of using the electromagnetic wave reflection device 10 on a vertically elongated production line 3, such as... Figure 3B As shown, it is preferable to guide the electromagnetic wave to the wireless communication unit WT of the machine in the production line 3 with a reflection angle θref smaller than the incident angle θin of the electromagnetic wave incident from the base station BS.

[0062] Electromagnetic waves reflected by metareflectors may not be plane waves with a single reflection angle. This can be achieved by studying the surface impedance formed on the surface of metareflector 102b, such as... Figure 3C As shown, the incident electromagnetic wave propagates in multiple directions with multiple different reflection angles θref. As a realization Figure 3CMethods of reflection include, for example, the method described in "ARBITRARY BEAM CONTROL USING LOSSLESS METASURFACES ENABLED BYORTHOGONALLY POLARIZED CUSTOM SURFACE WAVES" on page 97 of the journal *PHYSICAL REVIEW* (B issue). The intensity of the diffused electromagnetic wave can be uniform or it can have a prescribed intensity distribution according to the direction of reflection.

[0063] Multiple electromagnetic wave reflectors 10 can also be configured along the production line 3. As long as the communication quality between the base station BS and the machines within the production line 3 can be maintained, the electromagnetic wave reflectors can also be used as safety barriers.

[0064] Before explaining the optimal configuration of the base station BS relative to the production line 3, the following details the structure of the electromagnetic wave reflecting device 10.

[0065] <Structure of Electromagnetic Wave Reflection Device>

[0066] Figure 4 This diagram illustrates the basic concept of the electromagnetic wave reflecting device 10 according to the embodiment. The electromagnetic wave reflecting device 10 is vertically disposed on the XY plane where a production line is installed. The height direction of the electromagnetic wave reflecting device 10 is the Z direction. The electromagnetic wave reflecting device 10 includes: a panel 13 having a reflective surface 105 for reflecting electromagnetic waves in a desired frequency band selected from 1 GHz to 170 GHz; and a support body 11 supporting the panel 13.

[0067] The reflective surface 105 of panel 13 reflects electromagnetic waves in a desired direction. The reflective surface 105 is formed by at least one of a standard reflector 101 that performs normal reflection and a meta-reflector 102 that is an artificial surface with reflection characteristics that control the incident electromagnetic waves. The standard reflector 101 may also include a reflective surface formed of inorganic conductive material or conductive polymer material.

[0068] The meta-reflector 102 is not limited in material, surface shape, or manufacturing method, as long as it can reflect the incident electromagnetic wave in a desired direction or diffuse it at a desired angle. Typically, a meta-surface is obtained by forming a metal patch with a sufficiently small wavelength on the surface of a conductor such as a metal through a dielectric layer. The meta-reflector 102 is positioned at any location on the reflecting surface 105 to match the design of the electromagnetic wave reflection direction.

[0069] The dimensions of panel 13 can be appropriately designed according to the environment in which it is used. As an example, panel 13 may have a width of 0.5m to 3.0m, a height of 1.0m to 2.5m, and a thickness of 3.0mm to 9.0mm. Considering ease of transport, installation, and assembly within the factory, the dimensions of panel 13 may also be approximately 1.4m × 1.8m × 5.0mm. A portion of panel 13 may also be transparent to visible light.

[0070] Panel 13 is supported by support body 11, allowing electromagnetic wave reflecting device 10 to stand independently. The mechanical structure of support body 11 can be arbitrary as long as it allows panel 13 to stand stably relative to the mounting surface (e.g., the XY plane). As described later, multiple electromagnetic wave reflecting devices 10 can also be connected and used. The overall height of electromagnetic wave reflecting device 10, including panel 13 and support body 11, is, for example, 1.5m to 2.5m, but it can also be set to a height of about 2.0m above the mounting surface.

[0071] In addition to the mechanical design for independently erecting the panel 13, the support 11 also has an electrical connection portion 15 that makes the potential surface of the reflection generated on the reflective surface 105 of the panel 13 continuous. When multiple electromagnetic wave reflecting devices 10 are connected and used, if the current flowing between the panels 13 of adjacent electromagnetic wave reflecting devices 10 (referred to as the reflected current) is blocked by the incident electromagnetic waves, the energy of the reflected electromagnetic waves is attenuated, and in addition, they radiate in unnecessary directions, resulting in a deterioration in communication quality.

[0072] In two adjacent panels, to ensure the continuity of the reflected current, it is preferable that the reference potential for reflection is transmitted at high frequency from one panel to the other through the support 11, and the reference potential is shared at high frequency between the two adjacent panels. The continuity of the reflected current is preferably as uniform as possible in the connection area of ​​the support 11. The structure of the reference potential for reflection generated on the reflective surface of the panel by the support can also be called the structure of the "reference" reference potential.

[0073] In order to enable one panel to transmit a reference potential and the other panel to share the reference potential via the electrical connection portion 15 of the support 11, it is preferable to study the edge treatment of the panel 13 and the suppression of its influence on reflection characteristics. The "edge" of the panel 13 refers to the end that connects two opposing main surfaces. The specific structure of the electrical connection portion is described in [reference needed]. Figures 7 to 9B To be described later.

[0074] Figures 5A to 5D This illustrates a variation of the electromagnetic wave reflecting device 10. Figure 5AIn the electromagnetic wave reflecting device 10A, the meta-reflector 102 is movably disposed. For a structure that allows the position of the meta-reflector 102 on the reflecting surface 105 to be variable, any structure can be adopted as long as interference between the meta-reflector 102 and the reflecting surface 105 can be suppressed. As an example, the rod 16 holding the meta-reflector 102 can be slidably mounted in the horizontal direction of the panel 13, and the position of the meta-reflector 102 on the rod 16 can be maintained so that it can move in the vertical direction.

[0075] The rod 16 can be made of a non-metallic material with a low dielectric constant that does not impede the reflective characteristics of the standard reflector 101 or the meta-reflector 102. The rod 16 can also be designed to have zero or minimal optical and mechanical interference at the panel interface. The meta-reflector 102 can move to an optimal position on the panel 13 based on the environment of the site where the electromagnetic wave reflecting device 10 is located, its positional relationship with the base station BS, etc. Figure 4 Similarly, the support body 11 has an electrical connection portion 15 inside.

[0076] Figure 5B This refers to the electromagnetic wave reflecting device 10B. In the electromagnetic wave reflecting device 10B, as a reinforcement to improve the rigidity of the panel 13, an inclined column 19 may be provided on the side of the panel 13 opposite to the reflecting surface 105. The inclined column 19 may, for example, be installed between the support body 11 that holds both ends of the panel 13.

[0077] exist Figure 5C In the electromagnetic wave reflecting device 10C, reinforcing beams 21a and 21b are provided above and below the panel 13. The reinforcing beams 21a and 21b can be inserted between the support bodies 11 on both sides of the supporting panel 13.

[0078] exist Figure 5D In the electromagnetic wave reflecting device 10D, inclined columns 19 are provided between the reinforcing beams 21a or 21b and the support body 11. These reinforcing mechanisms suppress the vibration modes of the panel 13, stabilize electromagnetic wave reflection relative to the vibration of the factory floor, and enable the lightweighting of large-area panels. Figures 5B to 5D In the support body 11, an electrical connection portion 15 for referencing the reflected reference potential is provided inside, which is consistent with... Figure 4 same.

[0079] Figures 5A to 5D The variations can be combined with each other. For example, when using Figure 5A In the case of panel 13 with the same structure, the meta-reflector 102 can be movably held on the side of the reflective surface 105, and the inclined column 19 can be placed on the side opposite to the reflective surface 105.

[0080] <Structure of the Reflecting Surface>

[0081] Figures 6A to 6D This illustrates an example of the configuration of the reflective surface 105. The reflective surface 105 can have any structure, as long as it reflects electromagnetic waves in the range of 1 GHz to 170 GHz. As an example, the reflective surface 105 can be formed from a mesh conductor, a conductive film, a combination of transparent resin and a conductive film, etc., that reflects electromagnetic waves in any frequency band selected from the range of 1 GHz to 170 GHz.

[0082] By designing the reflector 105 to reflect radio waves in the desired frequency band from 1GHz to 170GHz, it can cover the 1.5GHz and 2.5GHz bands, which are the main frequency bands used in current mobile communications in Japan. In next-generation 5G communication networks, the 4.5GHz and 28GHz bands are expected. Overseas, the 2.5GHz, 3.5GHz, 4.5GHz, 24-28GHz, and 39GHz bands are expected to be used as 5G frequency bands. It can also handle the upper limit of the millimeter-wave band, 52.6GHz, which is the standard frequency for 5G.

[0083] On the other hand, frequencies exceeding 170 GHz are unlikely to be practically utilized for smart factory applications at this stage. In the future, in the case of realizing indoor terahertz frequency band mobile communication, photonic crystal technology and other methods can be applied to extend the reflection band of reflector 105 to the terahertz band.

[0084] exist Figure 6A In this design, panel 13A has a reflective surface 105 of conductor 131. Conductor 131 may not be a uniform conductive film, as long as it can reflect at least 30% of electromagnetic waves in the 1GHz to 170GHz frequency range. For example, it may be a mesh, a grid, or an arrangement of holes, formed to reflect electromagnetic waves in the aforementioned frequency band. The repeating interval forming the aforementioned density may be a uniform period or non-uniform. This period or average period is preferably 1 / 5 or less of the wavelength of the aforementioned frequency, more preferably 1 / 10 or less.

[0085] Metal mesh fences commonly used in factories or warehouses typically have opening diameters of 3.2cm, 4cm, and 5cm, allowing most electromagnetic waves in the 1GHz to 170GHz range to pass through. Even in the vicinity of 1GHz to several GHz, where electromagnetic waves are slightly reflected by the metal mesh fence, it can be considered that the transmission component dominates in the frequency bands above these ranges, making it impossible to obtain stable reflections that would improve the communication environment.

[0086] exist Figure 6BIn this design, panel 13B is a standard reflector, having a stacked structure of conductor 131 and dielectric 132 that is transparent relative to the operating frequency. Either surface of conductor 131 becomes a reflecting surface 105. When an electromagnetic wave is incident from one side of conductor 131, the interface between conductor 131 and air becomes the reflecting surface 105. When an electromagnetic wave is incident from one side of dielectric 132, the interface between conductor 131 and dielectric 132 becomes the reflecting surface 105.

[0087] The dielectric 132 that holds the conductor 131 or covers the surface of the conductor 131 preferably has rigidity capable of withstanding vibration, meeting the safety requirements of ISO 014120 (International Organization for Standardization). Since it is used in a factory, it is preferable that it can withstand impact and provide protection even if a component or part of the manufacturing machine collides with it, and more preferably that it is transparent in the visible light region. As an example, optical plastics, reinforced plastics, reinforced glass, etc., with strength exceeding the specified value are used. As optical plastics, polycarbonate (PC), polymethyl methacrylate (PMMA), polystyrene (PS), etc., can be used.

[0088] exist Figure 6C In the middle, panel 13C has a conductor 131 sandwiched between dielectrics 132 and 133. Depending on the incident direction of the electromagnetic wave, the interface with either dielectric becomes a reflecting surface 105. The required rigidity of dielectrics 132 and 133 is... Figure 6B The structures are the same.

[0089] exist Figure 6D In the middle, panel 13D can also be used. Figure 6B A portion of the laminate has a metareflector 102. The laminate of conductor 131 and dielectric 132 can be used as a standard reflector 101. The metareflector 102 can also be fixed to the surface of the dielectric 132 of the standard reflector 101 by bonding or the like. The region of the three-layer structure of conductor 131, dielectric 132, and metareflector 102 can become an asymmetric reflection region AS forming a metasurface. The region of the two-layer structure of conductor 131 and dielectric 132 without the metareflector 102 becomes a symmetric reflection region SY capable of providing normal reflection.

[0090] exist Figure 6D In the example, metareflector 102, such as Figure 4 As shown, it is integrally assembled with the standard reflector 101 onto the panel 13D, but it can also be used detachably from the standard reflector 101. As a detachable structure, such as... Figure 5AAs shown, a metamorphic reflector 102 with a variable position can also be used. By selecting the position of the metamorphic reflector 102 on the panel 13 according to the site environment, the position of the asymmetric reflection area can be adjusted.

[0091] <Connection Structure of Support Body>

[0092] like Figure 7 As shown, multiple electromagnetic wave reflecting devices 10 can also be connected using the support body 11 and disposed on surface P. For example, when electromagnetic wave reflecting devices 10-1 and 10-2 are connected, panels 13-1 and 13-2 are connected at the electrical connection portion 15 of the support body 11 in a manner where the reflected potential surfaces are continuous. As described above, the support body 11 has the mechanical strength to connect the panels 13 and the electrical connection performance to ensure the continuity of the reflected reference potential between the panels 13. Hereinafter, an example of the configuration of the electrical connection portion 15 is shown.

[0093] Figure 8 An electromagnetic wave reflecting device 10 is placed on surface P (refer to...). Figure 7 The horizontal cross-sectional view at the time shows an example of the electrical connection portion 15 of the support body 11. The connection portion 15 is designed to transmit the reference potential of the reflection of one panel to an adjacent panel, so that the reference potential of the reflection phenomenon is shared between adjacent panels 13.

[0094] The support 11 has a frame 111 and an electrical connection portion 15 disposed on the frame 111 and sharing a reflective potential surface between the panels 13. The connection portion 15 can be of any structure as long as it can stably transmit or share the reflected reference potential between adjacent panels 13-1 and 13-2 (hereinafter, suitably collectively referred to as "panels 13"). The frame 111 can be of any structure as long as it has the strength to stably maintain the electrical connection portion 15. Figure 8 In the structure, the frame 111 can also be formed of an electrically insulating material.

[0095] exist Figure 8In this example, the connecting portion 15 includes: conductive edge sleeves 17-1 and 17-2 (hereinafter, appropriately collectively referred to as "edge sleeve 17") that hold the edges of panel 13, and a bridge electrode 112 that electrically connects edge sleeve 17 to an adjacent panel. Bridge electrode 112 is an example of a conductive bridge spanning the potential surfaces of panels 13-1 and 13-2. Edge sleeves 17-1 holding the edges of panel 13-1 and 17-2 are electrically connected via bridge electrode 112. Bridge electrode 112 contacts the surfaces of edge sleeves 17-1 and 17-2, ensuring a reliable electrical connection. If a reflected current is generated in panel 13-1, the reflected current flows from edge sleeve 17-1 through bridge electrode 112 to edge sleeve 17-2, and then into conductor 131 of panel 13-1. The reflected current flows in a short current path, reducing current creep and resulting in good reflection performance.

[0096] Here, the reflected current is determined using general-purpose three-dimensional electromagnetic field simulation software. A plane wave is incident on the model including the connecting part 15. The reflection characteristics are analyzed, the scattering cross-section is examined, and the current path is determined based on the current distribution across the cross-section, thereby establishing a suitable range. Methods for three-dimensional electromagnetic field simulation include, for example, the FDTD method, the finite element method, and the moment method. The current path relative to the straight-line distance between the panels is 50 times or less, preferably 10 times or less, more preferably 5 times or less, and even more preferably 2 times or less.

[0097] Furthermore, the conductive material portion of the connecting portion 15, i.e., the corner of the bridge electrode 112 or the metal layer 121 in the modified example described below, is chamfered to stabilize the scattering at the edge of the conductor, which is therefore preferable. The radius of curvature R at the chamfered portion is at least R = 1 mm or more, preferably 2 mm or more, more preferably 4 mm or more, and even more preferably 8 mm or more.

[0098] The frame 111 is configured to ensure the strength of the support 11. Since the frame 111 is formed of an insulating elastomer, resin, or the like, no shunting of reflected current occurs, which is therefore preferable. Furthermore, the above-mentioned preferred options are also applicable to the variations described below.

[0099] Figure 9A and Figure 9B This shows an example of edge processing for panel 13. Figure 9A In the middle, panel 13 has a conductor 131 sandwiched between dielectrics 132 and 133 as a reflective surface 105. Edge sheath 17, as an example, can be a conductive track with an open square or U-shaped cross-section, having a set of outer surfaces 171 and a bottom surface 172 connecting the outer surfaces 171. A conductive adhesive material 18, such as silver paste, can also be pre-coated onto the inner surface of edge sheath 17.

[0100] Conductor 131 can be folded back at the edge of panel 13 and led out to the surface of at least one dielectric. When the edge of panel 13 is inserted into edge sleeve 17, the folded portion 131a of conductor 131 contacts the inner wall surface of edge sleeve 17. By leading conductor 131 out to the surface of panel 13 at the folded portion 131a, the contact area between conductor 131 and edge sleeve 17 is increased, and the electrical connection is stable.

[0101] like Figure 9B As shown, the thickness of dielectrics 132 and 133 can also be reduced along the edge of panel 13 to form a cut 134. Alternatively, a structure can be adopted where the thinned edge region due to the cut 134 fits into the edge sheath 17. In this structure, the outer surface 171 of the edge sheath is aligned with the surface of panel 13, facilitating operation of panel 13.

[0102] Figures 10A to 10E This shows a modified example of the connecting portion 15 of the support body 11. Figure 10A In this design, the support body 11A has a frame 111A made of carbon-containing material instead of an insulating frame 111. An electrical connection portion 15A is formed by the frame 111A and edge sheaths 17-1 and 17-2. CFRP (Carbon Fiber Reinforced Plastics) can be used as the carbon-containing material. By combining carbon fiber and resin, high strength can be achieved by integrally molding the carbon fiber (as a conductor) and the resin (as an insulator) using a continuous drawing molding manufacturing method.

[0103] The CFRP of the edge sheaths 17-1 and 17-2 itself serves as the electrical connection 15A. This allows for an electrical connection between the edge sheaths 17-1 and 17-2 without the use of the bridge electrode 112. From a reflective point of view, carbon fiber exhibits superior reflective properties compared to metal blocks, and the frame 111A itself also possesses excellent reflective characteristics.

[0104] To achieve both reflectivity and strength, the carbon fiber content of CFRP is preferably 50% or more, 60% or more, 70% or more, 80% or more, or 90% or more. On the other hand, the resin content of CFRP is preferably 50% or less, 40% or less, 30% or less, 20% or less, or 10% or less.

[0105] exist Figure 10BIn this structure, the support 11B has a frame 111B formed by stacking a metal layer 121 and a resin layer 122. The metal layer 121 connects the panels 13-1 and 13-2 in the form of covering edge sleeves 17-1 and 17-2. The metal layer 121 in contact with the edge sleeves 17-1 and 17-2 forms an electrical connection portion 15B. The resin layer 122 reinforces the connection between the panels based on the metal layer 121 from the outside. In this structure, current creep is minimal. The combined structure of the metal layer 121 and the resin layer 122 makes the design and manufacturing of the frame 111B easy. When viewed from the stacking direction, the strength of the frame 111B is also ensured by sandwiching the metal layer 121 with the resin layer 122.

[0106] Figure 10C Will Figure 8 The edge-treated panels 13 are connected to each other. The surface of the panel 13 is aligned with the outer wall of the edge sleeve 17, so the panel 13 can be inserted into the frame 111C with the edge sleeve 17 pre-embedded in the edge of the panel 13. The frame 111C is formed, for example, of insulating plastic. In the electrical connection 15C, reflected current flows from the edge sleeve 17 through the bridge electrode 112C into the conductor 131 of the adjacent panel in a short current path. The bridge electrode 112C can also be formed with a wide amplitude so as to contact the entire surface of the outer surfaces of the edge sleeves 17-1 and 17-2. When electromagnetic waves are reflected at the panel 13-1, as shown by the white arrow, high-frequency current flows through at least a portion of the bridge electrode 112C into the conductor 131 of the panel 13-2, thus minimizing current creep.

[0107] Figure 10D This section illustrates an example of the configuration of the connecting portion 15D of the support body 11D. The connecting portion 15D has a bridge electrode 114 that electrically connects the edge sleeves 17-1 and 17-2. The bridge electrode 114 electrically connects the bottom surfaces 172 of the edge sleeves 17-1 and 17-2 to each other. Figure 10D The structure is advantageous in that it allows for the shortest path flow from conductor 131-1 to edge sheath 17-1, bridge electrode 114, edge sheath 17-2, and conductor 131-2 at high frequencies. Figure 10D In the example, bridge electrode 114 connects a portion of the bottom surface 172 of edge sleeves 17-1 and 17-2, but the thickness of bridge electrode 114 can also be increased to connect the entire bottom surface 172 of edge sleeves 17-1 and 17-2. By making bridge electrode 114 thicker, the electrical connection and physical connection are more stable. By surrounding bridge electrode 114 with an insulating frame 111D, the mechanical strength of electrical connection portion 15D and the reliability of electrical connection are ensured.

[0108] Figure 10EThis illustrates an example of a composite frame 111E using metal and resin. It includes a metal connector 141 and a resin reinforcement 142 covering the connector. The connector 141 is easily manufactured using methods such as extrusion molding, ensuring electrical connection, and the connector itself also possesses a certain degree of strength. By covering the connector with the resin reinforcement 142, the strength of the connector as a support member is ensured by both the connector 141 and the resin reinforcement 142. This reduces the thickness of the connector 141, suppressing the generation of residual inductance due to current detours. Furthermore, rounding the ends prevents diffraction at the corners.

[0109] Figure 10F The example shown is a conventional frame 1100 formed by extrusion molding of aluminum. In the frame 1100, which has a complex cross-sectional shape, current flows in various directions, generating residual inductance and stray capacitance due to complex current routing paths. Since this response varies complexly with incident electromagnetic waves, it adversely affects the reference or transmission of the reference potential. From these perspectives, the connection 15 of the support 11 preferably uses... Figure 8 and Figures 10A to 10E The structure shown.

[0110] <Panel Links>

[0111] Figure 11A This diagram illustrates the connection between electromagnetic wave reflecting devices 10-1 and 10-2. Edge sleeves 17-1 are provided on both sides of the edge of panel 13-1. Edge sleeves 17-2 are provided on both sides of the edge of panel 13-2. Panels 13-1 and 13-2, with edge sleeves 17-1 and 17-2 pre-embedded, are connected by support body 11.

[0112] The support 11 may also include a frame 111 with an electrical connection portion 15 and a guide beam 118 for receiving the frame 111. For example... Figure 11A As in the example configuration, the frame 111 and the guide beam 118 can be formed separately or integrally. When the frame 111 receives the panels 13-1 and 13-2 from both sides, the bridge electrode 112 of the connecting portion 15 makes contact with both the outer surface of the edge sheath 17-1 of panel 13-1 and the outer surface of the edge sheath 17-1 of panel 13-2. Thus, an electrical connection is established between the reflecting surface 105-1 of electromagnetic wave reflecting device 10-1 and the reflecting surface 105-2 of electromagnetic wave reflecting device 10-2.

[0113] By embedding the frame 111 connecting panel 13-1 and panel 13-2 into the guide beam 118, the frame 111 and the guide beam 118 become a single unit, forming the support 11.

[0114] Figure 11BThis indicates the state of the electromagnetic wave reflecting device 10 before connection. In each of the electromagnetic wave reflecting devices 10-1 to 10-3, a frame 111 with an electrical connection part 15 is pre-installed on one side edge of the panel 13, and a guide beam 118 is installed on the other side edge. The reflecting surface 105 of the electromagnetic wave reflecting devices 10-1 to 10-3 can be... Figures 6A to 6D Any of the structures in it.

[0115] The frame 111 is configured to be embedded in a guide beam 118 that is disposed in other electromagnetic wave reflecting devices 10. The guide beam 118 is configured to receive the frame 111 disposed in other electromagnetic wave reflecting devices 10. For example, the guide beam 118 of electromagnetic wave reflecting device 10-1 receives the frame 111 of electromagnetic wave reflecting device 10-2. The guide beam 118 of electromagnetic wave reflecting device 10-2 receives the frame 111 of electromagnetic wave reflecting device 10-3. By combining the standard-sized electromagnetic wave reflecting devices 10 into a single unit, the length of the production line can be accommodated. Assembly can be performed on-site within the factory. The individual electromagnetic wave reflecting devices 10-1 to 10-3 have simple structures and are easy to transport.

[0116] Figure 11C This indicates the state of the connected electromagnetic wave reflecting device 10. The frame 111 and the guide beam 118 are integrated to form the support body 11. Multiple electromagnetic wave reflecting devices 10-1, 10-2, and 10-3 can also be connected through the support body 11 to form an electromagnetic wave reflecting fence 100. The electrical connection portion 15 of the frame 111 suppresses the discontinuity of the reflected current at the connection portion between the panels 13.

[0117] By pre-setting a base 119 on at least one of the guide beam 118 and the frame 111, the electromagnetic wave reflecting devices 10-1 to 10-3, which are connected, are independently erected on the mounting surface via the base 119 of the support body 11. Alternatively, the cover 29 can be placed over the edge of the panel 13 of the electromagnetic wave reflecting device 10-3 located at the far end, protecting the edge sheath 17 and the guide beam 118.

[0118] Figure 12 and Figure 13 This refers to a mechanism for strengthening the connection when multiple electromagnetic wave reflecting devices 10-1 and 10-2 are connected. Figure 12 (A) is the front view of the electromagnetic wave reflecting fence 100. Figure 12 (B) is a side view showing the state before the reinforcing mechanism 125 is tightened. Figure 12 (C) is a side view showing the state after the reinforcing mechanism 125 is tightened. Figure 13 This is a component example of strengthening agency 125. Figure 13(A) indicates the guide groove 129 formed by the mounting surface 127a of the cover 127 used in the reinforcing mechanism 125 and mounted on the panel 13. Figure 13 (B) indicates Figure 13 The state of section A and section B of (A).

[0119] To improve connection strength and electrical connectivity, appropriate methods can be used without degrading reflective properties. Figure 12 and Figure 13 The reinforcing mechanism 125 is shown. A hole 126 is formed in the panel 13, through which a pin 128 passes, and a cover 127 is mounted on the side of the panel 13 opposite to the reflective surface. By moving the pin 128 along the guide groove 129 formed in the mounting surface 127a of the cover 127, the panel 13 can be pressed against the support body 11 from both sides. By tightening the reinforcing mechanism 125, the position of the hole 126 formed in the panel 13 moves slightly toward the support body 11. Utilizing the elasticity of the panel 13, the edge of the panel 13 connects to the support body 11 at the connection portion 15 (see reference 126). Figure 13 The connection becomes reliable.

[0120] The mechanism for strengthening the connection of multiple electromagnetic wave reflecting devices 10 is not limited to Figure 12 , Figure 13 The example shown can also utilize appropriate zipper mechanisms, ratchet mechanisms, etc., within the range that does not impede the reflection characteristics of electromagnetic waves. The design of the edge sheath 17 and the connecting portion 15 can also be appropriately adjusted by assuming such a crimping process.

[0121] <Applications to Production Lines>

[0122] Figure 14 This is a diagram illustrating the dimensions of the metareflector 102. The transmitter is designated "Tx", and the receiver is designated "Rx". The transmitter Tx is, for example, a base station BS. The receiver Rx is, for example, a machine within a production line 3. The distance from the transmitter Tx to the surface 102S of the metareflector 102 is designated d1, and the distance from the surface 102S of the metareflector 102 to the receiver Rx is designated d2.

[0123] Assuming use in a production line, the total distance D between d1 and d2 is taken as an example as 40m (D = d1 + d2 = 40m). The standard length of the production line is 80m. Assuming that base stations (BS) are configured at both ends of the production line along its length, and that the two base stations provide a standard rectangular service area, denoted as D = 40m.

[0124] The radius R of the first Fresnel band when the radio wave emitted from the transmitter Tx and reflected by the meta-reflector 102 arrives at the receiver Rx in phase is defined by mathematical formula (1).

[0125] [Mathematical Expression 1]

[0126]

[0127] Here, λ is the wavelength used.

[0128] Figure 15 This represents a specific example of the radius R of the first Fresnel band derived from mathematical formula (1). At an operating frequency of 28 GHz, with d1 = 30 m and d2 = 10 m, the radius R of the first Fresnel band is 0.283 m. At the same frequency, with d1 = 35 m and d2 = 5 m, the radius R is 0.216 m.

[0129] At an operating frequency of 3.8 GHz, with d1 = 30 m and d2 = 10 m, the radius R of the first Fresnel band is 0.770 m. At the same frequency, with d1 = 35 m and d2 = 5 m, the radius R is 0.588 m.

[0130] For machine M configured on a production line, it is preferable to receive the reflected wave from electromagnetic wave reflector 10 in phase with the direct wave from base station BS, thereby improving reception strength. When applying electromagnetic wave reflector 10 using metareflector 102 to a production line, considering the first Fresnel band capable of in-phase reception, in the 28GHz band, as a minimum size for metareflector 102, the length of one side is preferably at least 0.5m. In the 3.8GHz band, as a minimum size for metareflector 102, the length of one side is preferably approximately 1m. Figures 5B to 5D As shown, when a panel 13 uses multiple meta-reflectors 102, the size of each meta-reflector 102 is preferably to at least cover the first Fresnel zone.

[0131] Since the radius R of the first Fresnel zone does not depend on the relationship between the incident angle and the reflection angle, the same calculation also applies to the standard reflector 101. In order to ensure that the radio waves incident on the standard reflector 101 are guided in phase to the receiver Rx through normal reflection, the size of the standard reflector 101 is preferably 50 cm or more on one side.

[0132] When the meta-reflector 102 is used in a production line covered by a service area with a large aspect ratio, the oblique incidence of either the incident angle or the reflection angle becomes deeper. The following examines the configuration relationship between the production line 3, the base station BS, and the electromagnetic wave reflecting device 10.

[0133] <Configuration Relationships of Wireless Transmission Systems>

[0134] Reference Figure 16A , Figure 16B , Figure 17A , Figure 17BThe configuration relationships of wireless transmission system 1 are explained below. (Refer to...) Figure 1 and Figure 2 As described, the wireless transmission system 1 includes: a base station BS for transmitting and receiving radio waves in the frequency band of 1 GHz to 170 GHz; a production line 3 equipped with production machines for transmitting and receiving the aforementioned radio waves; and an electromagnetic wave reflecting device 10 disposed along at least a portion of the production line. The electromagnetic wave reflecting device 10 has a reflecting surface 105 for reflecting radio waves in the aforementioned frequency band.

[0135] As detailed below, the base station BS is preferably located on one side of the production line 3 closer to the horizontal extension line L of the reflector surface 105. For example, the base station BS can be configured at both ends along the length of the production line 3. The production machines within the production line 3 can communicate with the base station BS directly or via the electromagnetic wave reflecting device 10 in the aforementioned frequency band.

[0136] Figure 16A This indicates mode 1 of reflection in the wireless transmission system 1. In mode 1, as shown by the solid arrow, the base station BS and the production line 3 are configured in the following positional relationship: radio waves emitted from the base station BS are incident at a deep angle relative to the perpendicular of the reflecting surface 105 of the electromagnetic wave reflecting device 10, and reflected at a shallow angle. That is, in mode 1, radio waves are incident at an angle of 45 degrees or more, and reflected at a reflection angle smaller than that of normal reflection.

[0137] To ensure that radio waves from the base station BS are incident on the reflecting surface 105 at a deep angle, it is preferable that the base station BS is located on the side of the production line 3 closer to the extension line L of the electromagnetic wave reflecting device 10, and at the end of the production line 3 along its length. By causing the radio waves to be incident on the reflecting surface 105 at a deep angle, radio waves can be transmitted to or near the center of the production line 3.

[0138] Figure 16B Mode 2 represents the reflection. In Mode 2, the base station BS and the production line 3 are configured in the following positional relationship: radio waves emitted from the base station BS are incident at a shallow angle relative to the perpendicular of the reflecting surface 105, and are reflected at an angle deeper than the angle of incidence. That is, in Mode 2, radio waves are incident at an angle of incidence less than 45 degrees, and are reflected in a manner where the reflection angle is larger than the normal reflection angle.

[0139] In Mode 2, the base station BS is located on one side of the production line 3 closer to the horizontal extension line L of the reflective surface 105 of the electromagnetic wave reflector 10, but closer to the center of the production line 3 than the end in the longitudinal direction. As explained below, in Mode 2, the effect on the deviation of the oblique incidence angle becomes greater.

[0140] Figure 17A Indicates the baseline robustness of mode 1. Figure 17B This indicates the baseline robustness of Mode 2. Baseline robustness refers to the stability of the reflection angle when the incident angle changes by 1 degree. High baseline robustness occurs when the change in the reflection angle is small relative to a 1-degree change in the incident angle.

[0141] exist Figure 17A In Mode 1, the anomalous angle θabn is changed to seven different values: 20°, 25°, 30°, 35°, 40°, 45°, and 50°. The variation of the reflection angle relative to the incident angle is estimated. The variations of the reflection angle under the seven anomalous angles θabn are roughly the same and overlap, thus appearing as a thick line in the graph.

[0142] For reference Figure 3B As explained, the anomalous angle θabn is the difference between the reflection angle of normal reflection and the reflection angle of asymmetric reflection in asymmetric reflection where the radio wave is reflected at a different angle than the angle of incidence. Changing the anomalous angle θabn to 20°–50° is equivalent to controlling the reflection direction of the asymmetric reflection within a 30-degree angular range.

[0143] Within the range of incident angles of 50° to 75° (deep incident angles), the variation of the reflection angle relative to a 1-degree change in the incident angle is less than 1 degree and remains approximately constant regardless of the incident angle. This indicates that at deeper incident angles, the controllability of reflection in asymmetric reflection is higher. It can be easily inferred that this represents a smaller variation in the reflection angle. Figure 17A The trend is maintained even when the angle of incidence exceeds 75° and reaches around 90°.

[0144] exist Figure 17B In Mode 2, the anomaly angle θabn is changed to seven values: 20°, 25°, 30°, 35°, 40°, 45°, and 50°. The variation of the reflection angle relative to the incident angle is estimated. Within the range of incident angles from 15° to 40° (shallow reflection), the variation of the reflection angle relative to the incident angle by 1 degree varies with the incident angle, and the deviation increases with the anomaly angle θabn.

[0145] When the anomalous angle θabn is small, i.e., the difference between the reflection angle and the normal reflection angle is small, the change in the reflection angle is less dependent on the incident angle. However, if the anomalous angle θabn is increased, i.e., the change in the reflection direction based on the metareflector 102 is increased, the change in the reflection angle relative to the incident angle of 1 degree becomes very large, and the amount of change in the reflection angle also varies significantly with the incident angle. Within a shallow range of incident angles of 15° to 40°, the controllability of reflection in asymmetric reflection is poor.

[0146] according to Figure 17A and Figure 17BWhen configuring a base station (BS) on production line 3, from the viewpoint of suppressing variations in the reflection angle that depend on the angle of incidence, it is preferable to configure the base station BS at a position where the angle of incidence toward the reflecting surface 105 of the electromagnetic wave reflecting device 10 is 50° or higher. Therefore, with Figure 16B Compared to the configuration shown, Figure 16A The configuration relationship is better.

[0147] Figure 18 This is a diagram illustrating the quantitative method for benchmark robustness. Figure 17A and Figure 17B The baseline robustness is estimated in the following order. Taking a certain incident angle θi and reflection angle θr as input, the phase jump Φ(x) is obtained using the function f of the phase jump distribution. Here, x is the position in the x-direction on the reflecting surface. The phase jump refers to the amount of phase applied to the reflected wave in order to make the reflected wave reflect at the desired angle. The phase jump distribution dΦ / dx is expressed as: sinθr-sinθi=(λ / 2π)(dΦ / dx). Here, λ is the wavelength used. If the surface impedance ZS and wave impedance η described in the non-patent literature, namely “PERFECT CONTROL OF REFLECTION AND REFRACTION USING SPATIALLY DISPERSIVE METASURFACES” published by VSAsadchy et al. in B issue of PHYSICAL REVIEW, are used, the function f for obtaining the phase jump distribution Φ(x) is expressed by mathematical formula 2.

[0148] [Mathematical Expression 2]

[0149]

[0150] arg() is a function representing the deflection angle on a complex number. The surface impedance Zs(x) is represented by mathematical formula 3.

[0151] [Mathematical Expression 3]

[0152]

[0153] Next, the incident angle is changed by 1 degree. The changed incident angle and reflection angle are used as inputs to calculate the phase jump Φ'(x) according to the phase jump distribution function f.

[0154] Find the reflection angle whose minimum value is Φ'(x)-Φ(x), and consider it as the variation of the reflection angle relative to the incident angle. Figure 17A and Figure 17B It is a graph plotted by treating the change in the calculated reflection angle as a function of the incident angle.

[0155] Figure 19A This represents the phase transition change in Mode 1. The horizontal axis represents position (m), and the vertical axis represents phase (degrees). Figure 19A In the Deep-in Shallow-out method, the reflection angle θr is fixed at 30 degrees, while the incident angle θi is varied to 68.5°, 70°, and 71.5°. At deep-angle incidence, even with changes in the incident angle within a 3° range, the distribution of the phase jump remains largely unchanged.

[0156] Figure 19B This represents the phase transition change in Mode 2. The horizontal axis represents position (m), and the vertical axis represents phase (degrees). Figure 19B In a shallow-in, deep-out incident projection, the reflection angle θr is fixed at 60 degrees, while the incident angle θi is varied to 18.5°, 20°, and 21.5°. In shallow-angle incident projections, if... Figure 19A Similarly, if the incident angle is changed within a range of 3°, the distribution of the phase jump will be significantly shifted due to the incident angle.

[0157] from Figure 19A and Figure 19B It can be seen that, in order to make the phase jump distribution of the electromagnetic wave incident on the electromagnetic wave reflecting device 10 uniform, Figure 16A configuration ratio Figure 16B More preferably. In Figure 16B In the configuration, the base station BS is positioned at the location where radio waves from the base station BS are incident on the reflecting surface 105 of the electromagnetic wave reflecting device 10 at an incident angle of more than 50 degrees.

[0158] The present invention has been described above based on specific configuration examples, but various modifications and substitutions can be made without departing from the scope of the invention. The meta-reflector 102 can adopt any structure as long as the reflection characteristics such as the reflection phase can be controlled, as long as a periodic structure with frequency selectivity or wavelength selectivity is appropriately designed.

[0159] Electromagnetic wave reflecting device 10 can, as Figure 16A As shown, it can be arranged on one side along the long side of production line 3, or as follows: Figure 2 As shown, the electromagnetic wave reflecting devices 10 are arranged on both sides of the production line 3. When the production line 3 is bent into an L-shape, the electromagnetic wave reflecting devices 10 can be installed in each area forming a rectangular region, or they can be installed on any main production line. In either case, the base station BS is positioned where the electromagnetic wave is incident on the reflecting surface 105 of the electromagnetic wave reflecting device 10 at a deep angle of incidence.

[0160] The machines within production line 3 do not necessarily need to receive only reflected waves from electromagnetic wave reflecting device 10; they can also directly receive radio waves emitted from base station BS. In this case, reception diversity can also be achieved through in-phase reception. When base stations BS are configured on both sides of the length of production line 3, coordinated base stations can also be used.

[0161] Each electromagnetic wave reflecting device 10 can also be like Figure 11A As shown, the panel 13 is transported with a frame 111 mounted on one opposite edge and a guide beam 118 mounted on the other. In this case, on-site assembly is simplified by eliminating the need for component installation. Alternatively, the panel 13 can be transported with only the frame 111 mounted, and assembly can be performed on-site using the guide beam 118. Furthermore, as... Figure 5A As shown, the positioning of the metasurface on the panel 13 can also be performed at the installation site of the electromagnetic wave reflecting device 10.

[0162] The electromagnetic wave reflection device and wireless transmission system implemented in this way contribute to the realization of smart factories.

[0163] This application claims priority to Japanese Patent Application No. 2020-064578, filed on March 31, 2020, including the entire contents of that patent application.

[0164] Explanation of reference numerals in the attached figures

[0165] 1…Wireless transmission system; 3…Production line; 10, 10A~10E, 10-1, 10-2…Electromagnetic wave reflection device; 11…Support body; 13, 13-1, 13-2…Panel; 15, 15A~15E…Connecting part; 16…Rod; 17, 17-1, 17-2…Edge sheath; 19…Inclined column; 100…Electromagnetic wave reflection fence; 101…Standard reflector; 102…Meta-reflector; 105…Reflective surface; 111, 111A~111E…Frame; 112, 112A, 114…Bridge electrode; 118…Guide beam; 125…Reinforcing mechanism; 131…Conductor; 132, 133…Dielectric; BS, BS1, BS2…Base station; WT, WT1, WT2…Wireless communication unit; SY…Symmetrical reflection area; AS…Asymmetric reflection area.

Claims

1. A radio transmission system, wherein, Possessing: a base station that transmits and receives an electric wave of a desired frequency band selected from a frequency band of 1 GHz to 170 GHz; and an electromagnetic wave reflection device that is disposed along at least a portion of a production line in which a production machine that transmits and receives the electric wave is disposed, and has a reflection surface that reflects the electric wave, a plurality of the electromagnetic wave reflection devices are mechanically and electrically connected, the electromagnetic wave reflection device has: a panel that has a reflection surface that reflects the electric wave; and a support body that supports the panel.

2. The wireless transmission system according to claim 1, wherein the base station is located on a side of the production line further from an extension of the reflection surface.

3. The wireless transmission system according to claim 1 or 2, wherein the electromagnetic wave reflection device is disposed on both sides of the production line along the at least a portion of the production line.

4. The wireless transmission system according to claim 1 or 2, wherein the base station includes a first base station and a second base station disposed at both ends in a length direction of the production line, the production machine is capable of communicating with at least one of the first base station and the second base station in the frequency band.

5. The wireless transmission system according to claim 1 or 2, wherein the reflection surface has a symmetrical reflection region that reflects the electric wave at a reflection angle identical to an incident angle of the electric wave, and an asymmetrical reflection region that reflects the electric wave at a reflection angle different from the incident angle.

6. The wireless transmission system according to claim 5, wherein the incident angle of the electric wave transmitted by the base station that is incident on the asymmetrical reflection region is 50° or more.

7. The wireless transmission system according to claim 5, wherein an area of the asymmetrical reflection region covers at least a first Fresnel zone determined by a frequency of the electric wave.

8. The wireless transmission system according to claim 1, wherein the base station is disposed at a position at which an incident angle of the electric wave transmitted by the base station that is incident on the reflection surface is 50° or more.

9. The wireless transmission system according to claim 1 or 2, wherein the reflection surface has an aperture arrangement formed so as to reflect the electric wave of the frequency band, and an average period of the aperture arrangement formed so as to have a density is 1 / 5 or less of a free space wavelength of the frequency band.

10. The wireless transmission system according to claim 9, wherein the aperture arrangement includes a mesh and a lattice.

11. The wireless transmission system according to claim 1 or 2, wherein the support body has an electrical connection portion that makes a potential surface of reflection generated at the reflection surface of the panel of the plurality of electromagnetic wave reflection devices continuous.

Images