Electromagnetic wave reflecting device, electromagnetic wave reflecting fence, and method for assembling an electromagnetic wave reflecting device

Abstract

To improve radio propagation of mobile communications within production facilities such as a factory and a plant.SOLUTION: An electromagnetic wave reflector comprises a panel that has a reflecting surface for reflecting a desired band of electric waves, selected from among frequency bands of 1-170GHz, and a substrate for supporting the panel. The substrate has a connection part that is electrically connected to the reflecting surface. The connection part transfers a reference potential of a reflection phenomenon on the reflecting surface.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an electromagnetic wave reflecting device, an electromagnetic wave reflecting fence, and a method for assembling an electromagnetic wave reflecting device. [Background technology]

[0002] The Industrial IoT (Internet of Things) is advancing, automating manufacturing processes and introducing advanced production and process management and predictive maintenance to manufacturing sites. Within the Industrial IoT, "smart factories" connect in-factory devices, equipment, and management systems to the cloud and edge AI (Artificial Intelligence) to streamline manufacturing processes. It is expected that mobile communication technologies such as 5G, which offer high speed, large capacity, low latency, and multiple simultaneous connections, will be introduced into the communication networks of the Industrial IoT, which handles large volumes of data. In addition to the mobility and flexibility inherent to mobile communication technologies, the low latency characteristics of 5G are said to be ideal for the Industrial IoT.

[0003] A joining structure for light-transmitting electromagnetic wave shielding plates used in structures such as intelligent buildings has been proposed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4892207 Summary of the Invention [Problem to be solved by the invention]

[0005] The communication environment in production facilities such as factories and plants is different from the public mobile communication environment. In production facilities, there are various machines and structures that obstruct the propagation of communication radio waves, making it difficult to achieve high communication quality.

[0006] The present invention aims to provide a technique for improving radio wave propagation for mobile communications within a production facility. [Means for solving the problem]

[0007] In one aspect of the present disclosure, an electromagnetic wave reflecting device includes: A panel having a reflective surface that reflects radio waves in a desired band selected from a frequency band of 1 GHz to 170 GHz; A support for supporting the panel; Equipped with The support has a connection portion electrically connected to the reflecting surface, and the connection portion transmits a reference potential for the reflection phenomenon occurring at the first reflecting surface. Effect of the Invention

[0008] The electromagnetic wave reflecting device having the above configuration improves radio wave propagation for mobile communications within production facilities such as factories and plants. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a process line in a factory to which the present disclosure can be applied. [Diagram 2] 1 is a schematic plan view of a wireless transmission system using an electromagnetic wave reflecting device according to an embodiment. [Figure 3A] FIG. 2 is a diagram illustrating reflection at a reflection angle that is the same as the incident angle. [Figure 3B] 1A and 1B are diagrams illustrating reflection at a reflection angle different from the incident angle. [Figure 3C] FIG. 1 is a diagram illustrating diffusion in multiple directions. [Figure 4] 1A and 1B are diagrams illustrating a basic concept of an electromagnetic wave reflecting device according to an embodiment. [Figure 5A] 13A and 13B are diagrams illustrating modified examples of an electromagnetic wave reflecting device. [Figure 5B] 13A and 13B are diagrams illustrating modified examples of an electromagnetic wave reflecting device. [Figure 5C] 13A and 13B are diagrams illustrating modified examples of an electromagnetic wave reflecting device. [Figure 5D]13A and 13B are diagrams illustrating modified examples of an electromagnetic wave reflecting device. [Figure 6A] 1 is a diagram showing an example of a configuration of a reflecting surface. [Figure 6B] 13 is another example of the configuration of the reflecting surface. [Figure 6C] 13 is yet another example of the configuration of the reflecting surface. [Figure 6D] 13 is yet another example of the configuration of the reflecting surface. [Figure 7] FIG. 13 is a diagram showing an example in which an electromagnetic wave reflecting device is connected. [Figure 8] FIG. 4 is a schematic diagram of a connection portion of a support. [Figure 9A] FIG. 11 is a diagram showing an example of edge processing of a panel. [Figure 9B] FIG. 13 is a diagram showing another example of edge processing of a panel. [Figure 10A] FIG. 4 is a diagram illustrating a configuration example of a connection unit. [Figure 10B] 13A and 13B are diagrams illustrating another configuration example of the connection portion. [Figure 10C] 13A and 13B are diagrams illustrating another configuration example of the connection portion. [Figure 10D] 13A and 13B are diagrams illustrating another configuration example of the connection portion. [Figure 10E] 13A and 13B are diagrams illustrating another configuration example of the connection portion. [Figure 10F] 13A and 13B are diagrams illustrating another configuration example of the connection portion. [Figure 10G] 13A and 13B are diagrams illustrating another configuration example of the connection portion. [Figure 10H] FIG. 1 is a diagram showing a general connection configuration as a reference example. [Figure 11A] FIG. 13 is a diagram illustrating the connection of multiple panels. [Figure 11B] FIG. 2 is a diagram showing the state of the electromagnetic wave reflecting device before connection. [Figure 11C] 13 is a diagram showing the state of the electromagnetic wave reflecting device after connection. FIG. [Figure 12] 11A and 11B are diagrams illustrating examples of reinforcement of connected electromagnetic wave reflecting devices. [Figure 13] FIG. 13 is a diagram illustrating an example of a fixing mechanism. [Figure 14] FIG. 1 is a schematic diagram of a model for evaluating the appropriate size of the frame and bridge electrodes. [Figure 15] FIG. 13 is a diagram showing the relationship between the width and thickness of a frame and the reflection characteristics when the incident angle is 0°. [Figure 16] FIG. 11 is a diagram showing the relationship between the width and thickness of a frame and the reflection characteristics when the incident angle is 45°. [Figure 17] 11 is a diagram showing the relationship between the width, thickness, and material of the bridge electrode and the reflection characteristics when the incident angle is 0°. FIG. [Figure 18] 11 is a diagram showing the relationship between the width, thickness, and material of the bridge electrode and the reflection characteristics when the incident angle is 45°. FIG. [Figure 19] FIG. 13 is a diagram illustrating a method for evaluating reflection characteristics. [Figure 20A] FIG. 2 is a diagram for explaining an analysis space of reflection characteristics. [Figure 20B] FIG. 2 is a diagram for explaining an analysis space of reflection characteristics. [Figure 21] FIG. 2 is a diagram of a simulation model used in the examples and comparative examples. [Figure 22] FIG. 11 is a diagram of a simulation model of the third embodiment. [Diagram 23] FIG. 13 is a diagram of a simulation model of Example 4. [Figure 24] FIG. 1 is a diagram of a simulation model of Reference Example 1. [Diagram 25] FIG. 11 is a diagram of a simulation model of Reference Example 2. [Figure 26] FIG. 13 is a diagram showing reflection characteristics according to whether or not the panels are connected to each other. [Figure 27] 11A to 11C are diagrams showing an example of a method for assembling a bridge electrode and a frame. [Figure 28] FIG. 4 is a diagram illustrating the size of a meta-reflector. [Figure 29] FIG. 13 is a diagram for considering zone sizes according to the operating frequency and the positional relationship between transmission and reception. [Figure 30A] FIG. 2 is a diagram illustrating the layout relationship of a wireless transmission system. [Figure 30B] FIG. 2 is a diagram illustrating the layout relationship of a wireless transmission system. [Figure 31A]FIG. 1 shows the criteria robustness of the reflection pattern 1. [Figure 31B] FIG. 13 is a diagram showing the criteria robustness of the reflection pattern 2. [Diagram 32] FIG. 13 is a diagram illustrating a method for quantifying criterion robustness. [Figure 33A] FIG. 13 is a diagram showing changes in phase jump of reflection pattern 1. [Figure 33B] FIG. 13 is a diagram showing changes in phase jump of reflection pattern 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] <Overall system image> Fig. 1 is a schematic diagram of a process line in a factory to which the present disclosure can be applied. The process line is a belt-shaped production site where equipment for assembly and production is arranged in a series of steps. In the industrial IoT, industrial devices, equipment, management systems, etc. used in the process line are connected to a network to improve production efficiency and ensure safety on site.

[0011] Base stations BS1 and BS2 are provided to connect devices in the process line to the network. Devices M1 and M2 used in the process line have wireless communication units WT1 and WT2, respectively, and communicate with at least one of the base stations BS1 and BS2 to be connected to the network.

[0012] To realize wireless connection between the process line equipment and the network, base stations BS1 and BS2 (hereinafter collectively referred to as "BS") provide a rectangular service area that is long in the horizontal direction. In the technical specification (TS22.104) of 3GPP (3rd Generation Partnership Project), a standardization organization for mobile communications, a service area with an aspect ratio of 3 to 5 times the rectangular area in the horizontal plane is specified as a system requirement. For example, the area size of a use case called "Motion Control" is specified as 50m x 10m x 10m in length x width x height.

[0013] In order to cover the process line with the service area provided by the base stations BS1 and BS2 and realize the network connection of the devices M1 and M2 existing in the process line, it is effective in terms of coverage to arrange the base stations BS1 and BS2 at the ends of the longitudinal direction of the process line. In order to improve the communication quality and coverage, the base stations BS1 and BS2 may cooperate and cooperate with each other. The detailed arrangement relationship of the base stations BS with respect to the process line will be described later.

[0014] 2 is a schematic plan view of a wireless transmission system 1 using an electromagnetic wave reflecting device 10 according to an embodiment. The wireless transmission system 1 includes a process line 3 on which production equipment capable of transmitting and receiving radio waves is arranged, a base station BS that performs wireless communication with the equipment on the process line 3, and an electromagnetic wave reflecting device 10 arranged along the process line 3. The electromagnetic wave reflecting device 10 has a reflecting surface 105 that reflects radio waves. The surface on which the process line is arranged is defined as an XY plane, and the height direction perpendicular to the XY plane is defined as a Z direction.

[0015] The equipment in the process line 3 includes all equipment related to production, such as microdevices such as sensors and actuators, assembly equipment, manufacturing machines, management systems, etc. The equipment used in the process line 3 is not limited to fixed devices or machines, and may be equipment that moves freely within the process line 3.

[0016] The base station BS and devices M1, M2 with wireless communication capabilities (see FIG. 1) transmit and receive radio waves in a specific frequency band, for example, in the range of 1 GHz to 170 GHz. The components of the process line and surrounding structures (e.g., ducts, pipes, etc.) are often made of metal, which reflects and blocks the radio waves. In addition, high-frequency radio waves such as those in the millimeter wave band tend to travel in a straight line and are less diffracted, making it difficult for the radio waves to reach the device. For devices located in the center of the process line 3, reflections from surrounding devices and metal products being processed can become an obstacle, deteriorating the communication environment.

[0017] Placing multiple base stations BS along the longitudinal direction of the process line 3 maintains communication quality, but this hinders efficient use of the work space and increases equipment costs. In the wireless transmission system 1, electromagnetic wave reflecting devices 10 are placed along the longitudinal direction of the process line 3, and base stations BS are placed at the longitudinal ends of the process line 3. The electromagnetic wave reflecting devices 10 reduce the number of base stations BS installed in the production facility and improve the wireless communication environment between the base stations BS and the equipment in the process line 3.

[0018] The electromagnetic wave reflecting device 10 may be installed approximately parallel to the long axis of the process line 3 with respect to at least a portion of the process line 3. "Almost parallel" means that the electromagnetic wave reflecting device 10 does not have to be arranged strictly parallel to the long axis of the process line 3. The electromagnetic wave reflecting device 10 may be slightly inclined with respect to the long axis of the process line 3 within a range where efficient transmission and reception of radio waves between the base station BS and the equipment in the process line 3 is performed.

[0019] The reflecting surface 105 of the electromagnetic wave reflecting device 10 reflects radio waves in the band of 1 GHz to 170 GHz. The reflecting surface 105 is formed of at least one of a normal reflector 101 that provides regular reflection with an equal angle of incidence and reflection, and a metareflector 102 having an artificial surface that controls the reflection characteristics of the incident electromagnetic wave. The "metareflector" is a type of "metasurface" that means an artificial surface that controls the transmission characteristics and reflection characteristics of the incident electromagnetic wave. The metareflector reflects radio waves in a predetermined direction other than the direction of regular reflection by arranging a large number of scatterers that are sufficiently small compared to the wavelength and controlling the reflection phase distribution and amplitude distribution. The metareflector 102 may realize not only reflection in a direction other than regular reflection, but also diffusion with a predetermined angle distribution and formation of a wavefront.

[0020] 3A to 3C show the manner of reflection at the reflecting surface 105 of the electromagnetic wave reflecting device 10. In Fig. 3A, the electromagnetic wave incident on the normal reflector 101 is reflected at a reflection angle θref that is the same as the incident angle θin.

[0021] In FIG. 3B, the electromagnetic wave incident on the metareflector 102a is reflected at a reflection angle θref different from the incident angle θin. The absolute value of the difference between the reflection angle θref by the metareflector 102 and the reflection angle by regular reflection may be called the abnormal angle θabn. As described above, a metal patch or the like sufficiently smaller than the wavelength used is arranged on the surface of the metareflector 102a to form a surface impedance, thereby controlling the reflection phase distribution and reflecting the incident electromagnetic wave in a desired direction. Although details will be described later, when the electromagnetic wave reflecting device 10 is used in the vertically long process line 3, it is desirable to guide the electromagnetic wave to the wireless communication unit WT of the equipment in the process line 3 at a reflection angle θref smaller than the incident angle θin of the electromagnetic wave incident from the base station BS, as shown in FIG. 3B.

[0022] The electromagnetic wave reflected by the meta-reflector does not have to be a plane wave with a single reflection angle. By devising the surface impedance formed on the surface of the meta-reflector 102b, the incident electromagnetic wave is diffused in multiple directions at multiple different reflection angles θref, as shown in FIG. 3C. As a method for realizing the reflection in FIG. 3C, for example, there is a method described in PHYSICAL REVIEW B 97, "ARBITRARY BEAM CONTROL USING LOSSLESS METASURFACES ENABLED BY ORTHOGONALLY POLARIZED CUSTOM SURFACE WAVES". The intensity of the diffused electromagnetic wave may be uniform, or may have a predetermined intensity distribution depending on the reflection direction.

[0023] A plurality of electromagnetic wave reflecting devices 10 may be arranged along the process line 3. As long as the communication quality between the base station BS and the equipment in the process line 3 is maintained, the electromagnetic wave reflecting devices may be used as a safety guard fence. Before describing the optimal arrangement of the base station BS relative to the process line 3, the configuration of the electromagnetic wave reflecting device 10 will be described in detail below.

[0024] <Configuration of the electromagnetic wave reflection device> 4 is a diagram illustrating the basic concept of an electromagnetic wave reflecting device 10 according to an embodiment. The electromagnetic wave reflecting device 10 is arranged upright on an XY plane on which a process line is provided. The height direction of the electromagnetic wave reflecting device 10 corresponds to the Z direction. The electromagnetic wave reflecting device 10 includes a panel 13 having a reflecting surface 105 that reflects radio waves in a desired band selected from a frequency band of 1 GHz to 170 GHz, and a support 11 that supports the panel 13.

[0025] The reflecting surface 105 of the panel 13 reflects electromagnetic waves in a desired direction. The reflecting surface 105 is formed of at least one of a normal reflector 101 that reflects electromagnetic waves in a regular manner and a meta-reflector 102 that has an artificial surface that controls the reflection characteristics of the incident electromagnetic waves. The normal reflector 101 may include a reflecting surface formed of an inorganic conductive material or a conductive polymer material.

[0026] The material, surface shape, and manufacturing method of the metareflector 102 are not important as long as it can reflect the incident electromagnetic wave in a desired direction or diffuse it with a desired angular distribution. In general, a metasurface is obtained by forming a metal patch that is sufficiently smaller than the wavelength to be used on the surface of a conductor such as a metal, with a dielectric layer interposed between them. The metareflector 102 is placed at any position on the reflecting surface 105 according to the design of the reflection direction of the electromagnetic wave.

[0027] The size of the panel 13 may be appropriately designed depending on the environment in which it is used. As an example, the width of the panel 13 is 0.5 m to 3.0 m, the height is 1.0 m to 2.5 m, and the thickness is 3.0 mm to 9.0 mm. Considering the ease of transportation to a factory and the ease of installation and assembly, the size of the panel 13 may be approximately 1.4 m × 1.8 m × 5.0 mm. A part of the panel 13 may be transparent to visible light.

[0028] The panel 13 is supported by the support 11 so that the electromagnetic wave reflecting device 10 can stand independently. The mechanical structure of the support 11 may be any structure as long as it can stably stand the panel 13 on the installation surface (for example, the XY plane). As described later, a plurality of electromagnetic wave reflecting devices 10 may be connected for use. The overall height of the electromagnetic wave reflecting device 10 including the panel 13 and the support 11 is, for example, 1.5 m to 2.5 m, and may be set to a height of about 2.0 m from the installation surface.

[0029] The support 11 has a mechanical design for allowing the panels 13 to stand independently, as well as electrical connections 15 for continuing the potential surface of the reflection occurring at the reflecting surface 105 of the panel 13. When multiple electromagnetic wave reflecting devices 10 are connected for use, if the current flowing due to the incident electromagnetic wave (called the reflected current) is blocked between the panels 13 of the adjacent electromagnetic wave reflecting devices 10, the energy of the reflected electromagnetic wave is attenuated and is radiated in unnecessary directions, deteriorating the communication quality.

[0030] To ensure the continuity of the reflected current between two adjacent panels, it is desirable that the reference potential for the reflection is transmitted from one panel to the other panel at high frequency by the support 11, and that the reference potential is shared at high frequency between the two adjacent panels. It is desirable that the continuity of the reflected current is as uniform as possible in the connection region of the support 11. A configuration in which the support transmits the reference potential for the reflection generated on the reflective surface of the panel may be called a configuration that "references" the reference potential.

[0031] In order to enable the electrical connection 15 of the support 11 to transmit a reference potential in one panel and to share the reference potential in the other panel, it is desirable to devise measures such as processing the edge of the panel 13 and suppressing the influence on the reflection characteristics. The "edge" of the panel 13 means the end portion connecting two opposing main surfaces. The specific configuration of the electrical connection will be described later with reference to Figs. 7 to 9D.

[0032] 5A to 5DE show modified examples of the electromagnetic wave reflecting device 10. The installation surface of the electromagnetic wave reflecting device 10 is defined as a surface P. In the electromagnetic wave reflecting device 10A of FIG. 5A, the meta-reflector 102 is provided movably. The configuration for making the position of the meta-reflector 102 on the reflecting surface 105 variable may be any configuration as long as interference between the meta-reflector 102 and the reflecting surface 105 is suppressed. As one example, a rod 16 for holding the meta-reflector 102 may be attached to the panel 13 so as to be slidable in the horizontal direction, and the position of the meta-reflector 102 may be held on the rod 16 so as to be vertically movable.

[0033] The rod 16 may be made of a non-metallic material with a low dielectric constant that does not interfere with the reflection characteristics of the normal reflector 101 or the meta-reflector 102. The rod 16 may be designed to eliminate or minimize optical and mechanical interference at the panel interface. The meta-reflector 102 can be moved to an optimal position on the panel 13 depending on the environment of the site where the electromagnetic wave reflecting device 10 is installed, the positional relationship with the base station BS, and the like. The support 11 has an electrical connection part 15 inside, as in FIG. 4.

[0034] 5B shows an electromagnetic wave reflecting device 10B. In the electromagnetic wave reflecting device 10B, a brace 19 may be provided on the surface of the panel 13 opposite the reflecting surface 105 as a reinforcement for increasing the rigidity of the panel 13 of the electromagnetic wave reflecting device 10B. The brace 19 may be stretched between the supports 11 that hold both ends of the panel 13, for example.

[0035] 5C, reinforcing beams 21a and 21b are provided above and below the panel 13. The reinforcing beams 21a and 21b can be inserted between the supports 11 that support both sides of the panel 13.

[0036] In the electromagnetic wave reflecting device 10D of Fig. 5D, a brace 19 is provided between the reinforcing beam 21a or 21b and the support 11. These reinforcing mechanisms suppress the vibration mode of the panel 13, stabilize the electromagnetic wave reflection against vibrations on the factory floor, and realize a lightweight large-area panel. In Figs. 5B to 5D, an electrical connection 15 that references the reference potential of the reflection is provided inside the support 11, as in Fig. 4.

[0037] 5A to 5D may be combined with one another. For example, when using the panel 13 of the configuration of FIG. 5A, the meta-reflector 102 may be movably supported on the reflecting surface 105 side, and a brace 19 may be provided on the surface opposite the reflecting surface 105.

[0038] <Reflective surface configuration> 6A to 6D show examples of the configuration of the reflecting surface 105. The reflecting surface 105 may have any configuration as long as it is a surface that reflects electromagnetic waves of 1 GHz to 170 GHz. As an example, the reflecting surface 105 may be formed of a mesh conductor, a conductive film, a combination of a transparent resin and a conductive film, or the like that reflects electromagnetic waves of any frequency band selected from the range of 1 GHz to 170 GHz.

[0039] By designing the reflecting surface 105 to be capable of reflecting radio waves in a desired frequency band from 1 GHz to 170 GHz, it is possible to cover the 1.5 GHz band, 2.5 GHz band, etc., which are the main frequency bands currently used in mobile communications in Japan. The 4.5 GHz band, 28 GHz band, etc. are planned for the next-generation 5G communication network. In other countries, the 2.5 GHz band, 3.5 GHz band, 4.5 GHz band, 24-28 GHz band, 39 GHz band, etc. are planned as 5G frequency bands. It is also compatible with 52.6 GHz, which is the upper limit of the millimeter wave frequency band of the 5G standard.

[0040] On the other hand, at the present stage, it is unlikely that frequencies above 170 GHz will be used practically for smart factory applications. In the future, if indoor mobile communications in the terahertz band become a reality, the reflection band of the reflecting surface 105 may be extended to the terahertz band by applying photonic crystal technology, for example.

[0041] In FIG. 6A, panel 13A has reflecting surface 105 of conductor 131. Conductor 131 does not have to be a homogeneous conductor film as long as it can reflect 30% or more of radio waves in the range of 1 GHz to 170 GHz. For example, it may be a mesh, a lattice, or a hole arrangement formed with a density that reflects electromagnetic waves in the above frequency band. The repeat pitch that forms the density may be a uniform cycle or may be non-uniform. This cycle or the average cycle is preferably 1 / 5 or less of the wavelength of the above frequency, and more preferably 1 / 10 or less.

[0042] The opening diameters of wire mesh fences generally used in factories and warehouses are 3.2 cm, 4 cm, 5 cm, etc., and most electromagnetic waves between 1 GHz and 170 GHz are transmitted through the fence. Although electromagnetic waves may be slightly reflected by a wire mesh fence in the vicinity of 1 GHz to several GHz, it can be considered that the transmitted components are dominant in frequency bands above that, and stable reflection that leads to an improvement in the communication environment cannot be obtained.

[0043] 6B, panel 13B is a normal reflector, and has a laminated structure of conductor 131 and dielectric 132 that is transparent to the operating frequency. One of the surfaces of conductor 131 becomes reflecting surface 105. When electromagnetic waves are incident from the conductor 131 side, the interface between conductor 131 and air becomes reflecting surface 105. When electromagnetic waves are incident from the dielectric 132 side, the interface between conductor 131 and dielectric 132 becomes reflecting surface 105.

[0044] It is desirable that the dielectric 132 that holds the conductor 131 or covers the surface of the conductor 131 has a rigidity that can withstand vibration and satisfies the safety requirements of ISO014120 of the International Organization for Standardization (ISO). Since it is used in a factory, it is desirable that it can withstand and protect against impacts caused by collisions with parts or parts of manufacturing equipment, and further that it is transparent in the visible light range. As an example, optical plastics, reinforced plastics, reinforced glass, etc. that have a certain level of strength or more are used. As optical plastics, polycarbonate (PC), polymethyl methacrylate (PMMA), polystyrene (PS), etc. may be used.

[0045] In Fig. 6C, panel 13C has conductor 131 sandwiched between dielectric 132 and dielectric 133. Depending on the incident direction of the electromagnetic wave, the interface with either of the dielectrics becomes reflecting surface 105. The rigidity required for dielectrics 132 and 133 is similar to that of the configuration in Fig. 6B.

[0046] In Fig. 6D, the panel 13D may have a meta-reflector 102 in a part of the laminate of Fig. 6B. A laminate of a conductor 131 and a dielectric 132 may be used as a normal reflector 101. The meta-reflector 102 may be fixed to the surface of the dielectric 132 of the normal reflector 101 by bonding or the like. A region of the three-layer structure of the conductor 131, the dielectric 132, and the meta-reflector 102 may be an asymmetric reflection region AS forming a metasurface. A region of the two-layer structure of the conductor 131 and the dielectric 132 without the meta-reflector 102 may be a symmetric reflection region SY providing regular reflection.

[0047] In the example of Fig. 6D, the meta-reflector 102 is incorporated into the panel 13D integrally with the normal reflector 101 as in Fig. 4, but it may be used so as to be separable from the normal reflector 101. As a separable configuration, a position-variable meta-reflector 102 may be used as in Fig. 5A. The position of the asymmetric reflection area can be adjusted by selecting the position of the meta-reflector 102 on the panel 13 according to the on-site environment.

[0048] <Support body connection structure> As shown in Fig. 7, a plurality of electromagnetic wave reflecting devices 10 may be connected by supports 11 and arranged on a plane P. For example, when connecting electromagnetic wave reflecting devices 10-1 and 10-2, panels 13-1 and 13-2 are connected by electrical connection portion 15 of support 11 so that the reflection potential surface is continuous. As described above, support 11 has the mechanical strength to connect panels 13 and the electrical connection performance to make the reference potential of reflection continuous between panels 13. An example of the configuration of electrical connection portion 15 is shown below.

[0049] 8 shows an example of the electrical connection portion 15 of the support 11 in a horizontal cross-sectional view when the electromagnetic wave reflecting device 10 is standing on the plane P (see FIG. 7). The connection portion 15 is designed to be capable of transmitting 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.

[0050] The support 11 has a frame 111 and an electrical connection portion 15 provided on the frame 111 to make the reflection potential surface between the panels 13 common. The connection portion 15 may have any configuration as long as it can stably transmit or share the reflection reference potential between adjacent panels 13-1 and 13-2 (hereinafter collectively referred to as "panels 13" as appropriate). The frame 111 may have any configuration as long as it has the strength to stably hold the electrical connection portion 15. In the configuration of FIG. 8, the frame 111 may be formed of an electrically insulating material.

[0051] In the example of FIG. 8, the connection portion 15 includes conductive edge jackets 17-1 and 17-2 (hereinafter collectively referred to as "edge jackets 17") that hold the edges of the panel 13, and a bridge electrode 112 that electrically connects the edge jacket 17 to the adjacent panel. The bridge electrode 112 is an example of a conductive bridge that bridges the potential surfaces of the panels 13-1 and 13-2. The edge jacket 17-1 that holds the edge of the panel 13-1 and the edge jacket 17-1 that holds the edge of the panel 13-2 are electrically connected by the bridge electrode 112. The bridge electrode 112 is in surface contact with the edge jackets 17-1 and 17-2 to ensure electrical connection. When a reflected current occurs in the panel 13-1, the reflected current flows from the edge jacket 17-1 through the bridge electrode 112 to the edge jacket 17-2 and then flows into the conductor 131 of the panel 13-1. The reflected current flows through a short current path, there is little current leakage, and the reflection performance is good.

[0052] The width WFRM of frame 111 is preferably 150 mm or less, and more preferably 20 mm or more and 60 mm or less, from the viewpoint of connecting the panels while maintaining a common potential surface for reflection at and between panels 13. From the same viewpoint, the thickness of frame 111 is preferably 15 mm or less, more preferably 10 mm or less, and more preferably in the range of 2 mm or more and 7.5 mm or less.

[0053] The width WBRG of the bridge electrode 112 as a conductive bridge is preferably 100 mm or less, and more preferably 10 mm or more and 50 mm or less, from the viewpoint of making the reflection potential surface between the panels 13 common with as small a size as possible. From the same viewpoint, the thickness of the bridge electrode 112 is preferably 20 mm or less, more preferably 10 mm or less, and even more preferably 1 mm or more and 5 mm or less. The basis for the width and thickness of the frame 111 and the bridge electrode 112 will be described later with reference to Fig. 14 onwards.

[0054] Appropriate sizes of the frame 111 and the bridge electrode 112 can be determined by general-purpose three-dimensional electromagnetic field simulation software, as described later with reference to Fig. 19. As a solution method for the three-dimensional electromagnetic field simulation, for example, the FDTD method, the finite element method, the moment method, etc. can be used.

[0055] In addition, the corners of the conductive material portion of the connection portion 15, i.e., the bridge electrode 112 and the metal layer 121 described in the modified example below, may be chamfered with a predetermined curvature R to stabilize scattering at the edge of the conductor. The curvature radius R of the chamfered portion is at least R=1 mm or more, preferably 2 mm or more, more preferably 4 mm or more, and further preferably 8 mm or more. This will also be described later.

[0056] Frame 111 is provided to ensure the strength of support 11, and is preferably made of an insulating elastic body, resin, or the like, which prevents shunting of reflected current. The above-mentioned preferable ranges can also be applied to the modified examples described below.

[0057] 9A and 9B show examples of edge treatment of panel 13. In FIG. 9A, panel 13 has conductor 131 sandwiched between dielectric 132 and dielectric 133 as reflective surface 105. Edge jacket 17 may be, for example, a conductive rail having an open square or U-shaped cross-sectional shape, and may have a pair of outer surfaces 171 and a bottom surface 172 connecting outer surfaces 171. A conductive adhesive 18 such as silver paste may be applied to the inner surface of edge jacket 17 in advance.

[0058] The conductor 131 may be folded back at an edge of the panel 13 and drawn out to the surface of at least one of the dielectric layers. When the edge of the panel 13 is inserted into the edge jacket 17, the folded back portion 131a of the conductor 131 comes into surface contact with the inner wall of the edge jacket 17. By drawing the conductor 131 to the surface of the panel 13 at the folded back portion 131a, the contact area between the conductor 131 and the edge jacket 17 increases, and the electrical connection becomes stable.

[0059] 9B, along the edges of panel 13, dielectrics 132 and 133 may be reduced in thickness to form notches 134. The thinned edge regions formed by cutouts 134 may be configured to mate with edge jacket 17. In this configuration, outer surface 171 of edge jacket aligns with the surface of panel 13, making panel 13 easier to handle.

[0060] 10A to 10G show modified examples of the connection portion 15 of the support 11. In FIG. 10A, the support 11A has a frame 111A made of a carbon-containing material instead of the insulating frame 111. The frame 111A and the edge jackets 17-1 and 17-2 form the electrical connection portion 15A. As the carbon-containing material, CFRP (Carbon Fiber Reinforced Plastics) can be used. By combining carbon fiber and resin, the carbon fiber, which is a conductor, and the resin, which is an insulator, can be integrally molded by a manufacturing method such as continuous pultrusion molding, thereby achieving high strength.

[0061] The CFRP itself that holds the edge jackets 17-1 and 17-2 serves as the electrical connection portion 15A. The edge jackets 17-1 and 17-2 can be electrically connected to each other without using the bridge electrode 112. In terms of reflection, carbon fiber has better reflection performance than metal bulk, and the reflection characteristics of the frame 111A itself are also excellent. In order to achieve both reflection performance and strength, the carbon fiber content of the CFRP is preferably 50% or more, 60% or more, 70% or more, 80%, or 90% or more. On the other hand, the resin content of the CFRP is preferably 50% or less, 40% or less, 30% or less, 20% or less, or 10% or less.

[0062] In FIG. 10B, the support 11B has a frame 111B that is a laminate of a metal layer 121 and a resin layer 122. The metal layer 121 connects the panels 13-1 and 13-2 in a manner that covers the edge jackets 17-1 and 17-2. The metal layer 121 that contacts the edge jackets 17-1 and 17-2 becomes the electrical connection portion 15B. The resin layer 122 reinforces the connection between the panels by the metal layer 121 from the outside. An adhesive may be used for the reinforcement (i.e., the resin layer 122). The adhesive may be an acrylic adhesive or an epoxy adhesive. This configuration reduces the leakage of current. The combination of the metal layer 121 and the resin layer 122 makes it easy to design and process the frame 111B. When viewed in the lamination direction, the strength of the frame 111B is also ensured by sandwiching the metal layer 121 between the resin layers 122.

[0063] FIG. 10C shows a connection between panels 13 having the edge treatment of FIG. 8B. The surface of the panel 13 and the outer wall of the edge jacket 17 are aligned, so the edge jacket 17 is fitted to the edge of the panel 13 beforehand, and the panel 13 is inserted into the frame 111C. The frame 111C is made of, for example, insulating plastic. In the electrical connection portion 15C, the reflected current flows from the edge jacket 17 through the bridge electrode 112C to the conductor 131 of the adjacent panel via a short current path. The bridge electrode 112C may be formed to be wide so as to be in surface contact with the entire outer surfaces of the edge jackets 17-1 and 17-2. When the electromagnetic wave is reflected by the panel 13-1, as shown by the white arrow, the high-frequency current flows through at least a part of the bridge electrode 112C to the conductor 131 of the panel 13-2, so that there is little current leakage.

[0064] Fig. 10D shows a configuration example of a connection portion 15D of the support 11D. The connection portion 15D has a bridge electrode 114 that electrically connects the edge jackets 17-1 and 17-2. The bridge electrode 114 electrically connects the bottom surfaces 172 of the edge jackets 17-1 and 17-2 to each other. The configuration of Fig. 10D is advantageous in that high frequency waves flow from the conductor 131-1 to the edge jacket 17-1, the bridge electrode 114, the edge jacket 17-2, and the conductor 131-2 via the shortest path.

[0065] 10D, the bridge electrode 114 connects a part of the bottom surface 172 of the edge jackets 17-1 and 17-2, but the thickness of the bridge electrode 114 may be increased to connect the entire surface of the bottom surface 172 of the edge jackets 17-1 and 17-2. By making the bridge electrode 114 thicker, the electrical and physical connection becomes more stable. By surrounding the bridge electrode 114 with an insulating frame 111D, the mechanical strength of the electrical connection portion 15D and the reliability of the electrical connection are ensured.

[0066] FIG. 10E shows a configuration example of a connection part 15E of the support 11E. The connection part 15E has an H-shaped horizontal cross section in which a pair of opposing bridge electrodes 112a and 112b are connected by a bridge electrode 114. The bridge electrode 114 ensures an electrical connection over the entire bottom surface 172 of the edge jackets 17-1 and 17-2, and both the stability of the electrical connection and the mechanical strength are obtained. The bridge electrode 114 and the bridge electrodes 112a and 112b may be integrally formed. The frame 111E covering the connection part 15E may be formed of an insulating material such as a resin, or may be formed of CFRP. A curing adhesive may be used as the resin.

[0067] FIG. 10F shows an example of using a composite frame 111F of metal and resin. The frame 111F has a metal connector 141 and a resin reinforcement part 142 that covers the connector. The connector 141 is easily manufactured by extrusion molding, etc., and while ensuring electrical connection, the connector itself has a certain degree of strength. By covering the periphery with the resin reinforcement part 142, both the connector 141 and the resin reinforcement part 142 ensure their strength as support materials. The resin reinforcement part 142 may be an adhesive. The adhesive may be an acrylic adhesive or an epoxy adhesive. This reduces the thickness of the connector 141 and suppresses the generation of residual inductance due to current bypass. Furthermore, by rounding the ends, diffraction at the corners is prevented.

[0068] FIG. 10G shows a configuration example of the connection part 15G of the support 11G. The connection part 15G has a bridge electrode 173 having an H-shaped horizontal cross section, similar to FIG. 10E. In FIG. 10G, the panels 13-1 and 13-2 are fitted into the bridge electrode 173 without using an edge jacket, and the conductor 131 with the end folded back is directly electrically connected to the bridge electrode 173. The frame 111G covers the outer surface 173a of the bridge electrode 173. In FIG. 10G, the width WBRG of the bridge electrode is set shorter than the width of the frame 111G, and a configuration is adopted in which the panels 13-1 and 13-2 can be easily fitted into each other, but this is not limited to this example, and the widths of the frame 111G and the bridge electrode 173 may be the same. In the connection configurations of FIG. 8 and FIG. 10A to FIG. 10G, the surface of the bridge electrode may be coated with an insulating coating.

[0069] FIG. 10H shows, as a reference example, a structure using an existing frame 1100 formed by extrusion molding of aluminum. In the frame 1100 having a complex cross-sectional shape, current flows in various directions, and residual inductance and stray capacitance occur due to the complex current detouring paths. The response changes in a complex manner due to the incident electromagnetic wave, which adversely affects the reference or transmission of the reference potential. From these points of view, it is desirable to adopt the configurations shown in FIG. 8 and FIGS. 10A to 10G as the connection part 15 of the support 11.

[0070] <Panel connection> 11A is a diagram for explaining the connection between electromagnetic wave reflecting devices 10-1 and 10-2. An edge jacket 17-1 is provided on both edges of panel 13-1. An edge jacket 17-2 is provided on both edges of panel 13-2. Panels 13-1 and 13-2, to which edge jackets 17-1 and 17-2 have already been fitted, are connected by support 11.

[0071] The support 11 may have a frame 111 having an electrical connection portion 15 and a guide beam 118 that receives the frame 111. As in the configuration example of FIG. 11A, the frame 111 and the guide beam 118 may be formed as separate bodies, or may be integrally formed. When the frame 111 receives the panel 13-1 and the panel 13-2 from both sides, the bridge electrode 112 of the connection portion 15 comes into surface contact with both the outer surface of the edge jacket 17-1 of the panel 13-1 and the outer surface of the edge jacket 17-1 of the panel 13-2. This establishes an electrical connection between the reflecting surface 105-1 of the electromagnetic wave reflecting device 10-1 and the reflecting surface 105-2 of the electromagnetic wave reflecting device 10-2.

[0072] By fitting the frame 111 connecting the panel 13-1 and the panel 13-2 into the guide beam 118, the frame 111 and the guide beam 118 are integrated to form the support body 11.

[0073] Fig. 11B shows the state of the electromagnetic wave reflecting device 10 before being connected. In each of the electromagnetic wave reflecting devices 10-1 to 10-3, a frame 111 having an electrical connection portion 15 is attached in advance to one side edge of the panel 13, and a guide beam 118 is attached to the other side edge. The reflecting surface 105 of the electromagnetic wave reflecting devices 10-1 to 10-3 may have any of the configurations shown in Figs. 6A to 6D.

[0074] The frame 111 is formed so as to be able to be fitted into the guide beam 118 provided on another electromagnetic wave reflecting device 10. The guide beam 118 is formed so as to be able to receive the frame 111 provided on another electromagnetic wave reflecting device 10. For example, the guide beam 118 of the electromagnetic wave reflecting device 10-1 receives the frame 111 of the electromagnetic wave reflecting device 10-2. The guide beam 118 of the electromagnetic wave reflecting device 10-2 receives the frame 111 of the electromagnetic wave reflecting device 10-3. By combining and integrating electromagnetic wave reflecting devices 10 of a standard size, it is possible to correspond to the length of the process line. The assembly work can be performed on-site in the factory. Each of the electromagnetic wave reflecting devices 10-1 to 10-3 has a simple configuration and is easy to transport.

[0075] 11C shows the state of the electromagnetic wave reflecting device 10 after connection. The frame 111 and the guide beam 118 are integrated to form the support 11. A plurality of electromagnetic wave reflecting devices 10-1, 10-2, and 10-3 may be connected by the support 11 to form the electromagnetic wave reflecting fence 100. The electrical connection portion 15 of the frame 111 suppresses discontinuity of the reflected current at the connection portion between the panels 13.

[0076] By providing a base 119 in advance on at least one of the guide beam 118 and the frame 111, the connected electromagnetic wave reflecting devices 10-1 to 10-3 stand independently on the installation surface by the base 119 of the support body 11. A cover 29 may be placed on the edge of the panel 13 of the electromagnetic wave reflecting device 10-3 located at the very end to protect the edge jacket 17 and the guide beam 118.

[0077] Fig. 12 and Fig. 13 show a mechanism for reinforcing the connection when connecting a plurality of electromagnetic wave reflecting devices 10-1, 10-2. Fig. 12(A) is a front view of the electromagnetic wave reflecting fence 100, Fig. 12(B) is a side view showing the state before tightening of the reinforcement mechanism 125, and Fig. 12(C) is a side view showing the state after tightening of the reinforcement mechanism 125. Fig. 13 shows one configuration example of the reinforcement mechanism 125. Fig. 13 shows a front view of a guide groove 129 formed in a mounting surface 127a of a cover 127 used in the reinforcement mechanism 125 to be attached to the panel 13, and cross sections A and B.

[0078] In order to improve the connection strength and the electrical connection, a reinforcing mechanism 125 shown in Figs. 12 and 13 may be used as appropriate without deteriorating the reflection characteristics. A hole 126 is formed in the panel 13, a pin 128 is passed through the hole, and a cover 127 is attached to the surface of the panel 13 opposite to the reflection surface. By moving the pin 128 along a guide groove 129 formed in the mounting surface 127a of the cover 127 (transition from cross section A to cross section B), the panel 13 can be pressed against the support 11 from both sides. The position of the hole 126 formed in the panel 13 is slightly shifted toward the support 11 by tightening the reinforcing mechanism 125. The elastic force of the panel 13 ensures a connection between the edge of the panel 13 and the connection portion 15 (see Fig. 17) of the support 11.

[0079] The mechanism for strengthening the connection of the plurality of electromagnetic wave reflecting devices 10 is not limited to the examples shown in Fig. 12 and Fig. 13, and an appropriate fastener mechanism, ratchet, etc. may be used as long as it does not impair the reflection characteristics of the electromagnetic waves. The design of the edge jacket 17 and the connection portion 15 may be appropriately adjusted in consideration of such a pressure welding process.

[0080] <Evaluation of the support> The size and characteristics of the support 11 are evaluated below. Fig. 14 is a schematic diagram of a model for evaluating appropriate sizes of the frame 111 and bridge electrode 112. In this model, the preferable ranges of the width WFRM and thickness TFRM of the frame and the width WBRG and thickness TBRG of the bridge electrode are evaluated based on the reflection characteristics when a connection portion 15 that electrically connects two panels 13 is provided.

[0081] Figure 15 shows the relationship between the frame width and thickness and the reflection characteristics when the electromagnetic wave incidence angle is 0°. The reflection characteristics are shown as the peak ratio on the vertical axis. The peak ratio is expressed as the ratio of the peak intensity of the scattering cross section when electrical connections 15 are provided to the peak intensity of the scattering cross section of a single panel without electrical connections 15. An incidence angle of 0° corresponds to perpendicular incidence to the connections 15.

[0082] As shown in FIG. 19, the ability to reflect incident electromagnetic waves is evaluated by the radar cross section (RCS), i.e., the scattering cross section. The unit of RCS is square meter (sm). By connecting two panels with an electrical connection 15, the main peak intensity of the RCS is reduced compared to that of a single panel. The smaller the degree of reduction, i.e., the higher the ratio of the main peak intensity of the RCS when the connection 15 is provided to the main peak intensity of the RCS when the connection 15 is not provided, the better the reflection characteristics are.

[0083] In the evaluation, general-purpose three-dimensional electromagnetic field simulation software is used to reflect a 3.8 GHz plane wave and analyze the scattering cross section.

[0084] In FIG. 15(A), the frame thickness TFRM is fixed at 1 mm, and the width WFRM is changed in the range of 0 to 150 mm, while calculating the peak ratio of the scattering cross section. In FIG. 15(B), the frame width WFRM is fixed at 50 mm, and the thickness TFRM is changed in the range of 0 to 15 mm, while calculating the peak intensity ratio of the scattering cross section (hereinafter simply referred to as "peak ratio"). A peak ratio of 1.0 is the reflection characteristic of a single panel without electrical connection 15. For reference, the peak ratio when an aluminum frame with a thickness of 10 mm and a width of 50 mm is used is shown by a dashed line.

[0085] 15A, when the width WFRM of the frame 111 is 150 mm or less, the peak ratio is 0.85 or more, and when it is 60 mm or less, the peak ratio is 0.9 or more. From this, the width WFRM of the frame 111 is preferably 150 mm, and more preferably 20 mm or more and 60 mm or less.

[0086] 15B, when the thickness TFRM of the frame 111 is 15 mm or less, the peak ratio is higher than that of an aluminum frame. When the thickness is 10 mm or less, the peak ratio is 0.9 or more, and when the thickness is 7.5 mm, the peak ratio is maximum. Therefore, the thickness TFRM of the frame 111 is preferably 15 mm or less, more preferably 10 mm or less, and even more preferably 2 mm or more and 7.5 mm or less.

[0087] Figure 16 shows the relationship between the frame width and thickness and the reflection characteristics when the electromagnetic wave incidence angle is 45°. The simulation conditions are the same as those in Figure 15, except for the incidence angle. For reference, the peak ratio when an aluminum frame with a thickness of 10 mm and a width of 50 mm is used is shown by the dashed line.

[0088] At an incidence angle of 45°, as shown in Fig. 16A, when the width of frame 111 is 150 mm or less, the peak ratio is 0.85 or more, and when the width is 100 mm or less, the peak ratio is 0.9 or more. Combined with the result of Fig. 15A, the width WFRM of frame 111 is preferably 150 mm, and more preferably 20 mm or more and 60 mm or less.

[0089] In Fig. 16B, when the thickness of the frame 111 is 12 mm or less, the peak ratio is higher than that of an aluminum frame. When the thickness is 10 mm or less, the peak ratio is 0.9 or more, and when the thickness is 7.5 mm, the peak ratio is maximum. Combined with the results in Fig. 15B, the thickness TFRM of the frame 111 is preferably 12 mm or less, more preferably 10 mm or less, and even more preferably 2 mm or more and 7.5 mm or less.

[0090] FIG. 17 is a diagram showing the relationship between the width, thickness, and material of the bridge electrode and the reflection characteristics when the incident angle is 0°, and FIG. 18 is a diagram showing the relationship between the width, thickness, and material of the bridge electrode and the reflection characteristics when the incident angle is 45°. In FIG. 17(A), the peak ratio of the scattering cross section is calculated while changing the width WFRM of the bridge electrode in the range of 10 to 100 mm. In FIG. 17(B), the peak ratio of the scattering cross section is calculated while changing the thickness TFRM of the frame in the range of 1 to 50 mm. In FIG. 17(C), the peak ratio of the scattering cross section is calculated while changing the material of the bridge electrode to aluminum (Al), copper (Cu), and SUS. In FIG. 18(A) to (C), the peak ratio is calculated under the same conditions as FIG. 17, except that the incident angle is changed to 45°.

[0091] 17 and 18, the width WBRG of the bridge electrode 112 is preferably 100 mm or less, and more preferably 50 mm or less. The thickness of the bridge electrode is preferably 20 mm or less, more preferably 10 mm or less, and even more preferably 1 mm or more and 5 mm or less. As long as the material of the bridge electrode is a conductor such as Al, Cu, or SUS, differences in material do not have much effect on the reflection characteristics.

[0092] In Figures 17(B) and 18(B), the peak ratio is particularly high when the bridge electrode thickness is 40 mm. This is thought to be because the wavelength of an electromagnetic wave with a frequency of 3.8 GHz is 78.9 mm, and the thickness of the bridge electrode corresponds to half the wavelength, so the reflected waves reinforce each other (resonance phenomenon), increasing the scattering cross-section.

[0093] 20A and 20B are diagrams for explaining the analysis space of the reflection characteristics of Examples 1 to 8 and Reference Examples 1 to 4 described below. In FIG. 20A and FIG. 20B, the thickness direction of the panel is the x direction, the width direction is the y direction, and the height direction is the z direction, and the analysis space is expressed as (size in the x direction)×(size in the y direction)×(size in the z direction). The size of the analysis space when the frequency is 2 to 15 GHz is 150 mm×500 mm×500 mm. The size of the analysis space when the frequency is 28 GHz is 100 mm×200 mm×200 mm. The analysis space is made smaller at high frequencies because the wavelength becomes shorter. As shown in FIG. 20B, the boundary condition is designed to arrange electromagnetic wave absorbers around the analysis space.

[0094] Fig. 21 is a diagram of a simulation model used in the examples and reference examples. The panel 13 has a structure in which a conductor 131 is sandwiched between two dielectrics 132 and 133 and bonded together. The dielectrics 132 and 133 are made of glass or polycarbonate with a thickness of 2 mm. The conductor 131 is made of SUS with a thickness of 1 mm. The total thickness of the panel 13 is 5 mm. A gap of 10 mm is provided between the two panels 13. The structure and arrangement of the panel 13 are common to Examples 1 to 8 and Reference Examples 1 to 4. EXAMPLES

[0095] In the configuration of Figure 21, an aluminum plate with a thickness of 1 mm and a width of 50 mm is used as the bridge electrode (indicated as "BRG" in the figure) of the connection part 15. An FRP frame with a thickness of 5 mm and a width of 50 mm is provided on the outside of the aluminum plate. The radius of curvature R of the corners of the frame is 2 mm. The frequency of the incident electromagnetic wave is 3.8 GHz. An analysis space of 150 mm x 500 mm x 500 mm is set. The incident angle is changed from 0° to 60° in 10° increments, and the intensity ratio of the main peak of the scattering cross section is calculated. The calculation results are shown in Table 1.

[0096] [Table 1] EXAMPLES

[0097] In the configuration of Figure 21, an aluminum plate with a thickness of 1 mm and a width of 50 mm is used as the bridge electrode BRG of the connection part 15. An FRP frame with a thickness of 7.5 mm and a width of 50 mm is provided on the outside of the aluminum plate. The radius of curvature R of the corners of the frame is 2 mm. The frequency of the incident electromagnetic wave is 3.8 GHz. The incident angle is changed from 0° to 60° in 10° increments, and the intensity ratio of the main peak of the scattering cross section is calculated. The calculation results are shown in Table 2.

[0098] [Table 2] EXAMPLES

[0099] FIG. 22 is a simulation model of Example 3. In Example 3, the panels are connected with CFRP that functions as a bridge electrode and a frame. The horizontal cross section of the CFRP is H-shaped, and the gap G between the two panels is filled with CFRP. The thickness of the CFRP panel on the main surface is 2 mm, the width is 50 mm, and the radius of curvature R of the corner is 1 mm. The frequency of the incident electromagnetic wave is 3.8 GHz. The incident angle is changed from 0° to 60° in 10° increments to calculate the intensity ratio of the main peak of the scattering cross section. The calculation results are shown in Table 3.

[0100] [Table 3] EXAMPLES

[0101] FIG. 23 is a simulation model of Example 4. In Example 4, the panels 13 are connected with a two-layer structure of CFRP and FRP. The inner layer 161 in contact with the panel 13 is formed of CFRP, and the outer layer 162 is formed of FRP. The inner layer 161 functions as a bridge electrode and a part of the frame. The inner layer 161 made of CFRP has a thickness of 1 mm and a width of 50 mm on the main surface of the panel 13, and the corners are not chamfered. The FRP of the outer layer 162 has a thickness of 1 mm, and the corners are chamfered with a curvature radius R of 1 mm. The frequency of the incident electromagnetic wave is 3.8 GHz. The incident angle is changed from 0° to 60° in 10° increments, and the intensity ratio of the main peak of the scattering cross section is calculated. The calculation results are shown in Table 4.

[0102] [Table 4] EXAMPLES

[0103] In Example 5, in the model of the configuration of Figure 21, an aluminum plate with a thickness of 1 mm and a width of 50 mm is used as a bridge electrode, and a polycarbonate frame with a thickness of 7.5 mm and a width of 50 mm is placed on the outside. The frequency of the incident electromagnetic wave is 3.8 GHz. The incident angle is changed from 0° to 60° in 10° increments, and the intensity ratio of the main peak of the scattering cross section is calculated. The calculation results are shown in Table 5.

[0104] [Table 5] EXAMPLES

[0105] In Example 6, in the model of the configuration of Figure 21, an aluminum plate with a thickness of 1 mm and a width of 50 mm is used as a bridge electrode, and a polymethyl methacrylate frame with a thickness of 7.5 mm and a width of 50 mm is placed on the outside. The frequency of the incident electromagnetic wave is 3.8 GHz. The incident angle is changed from 0° to 60° in 10° increments, and the intensity ratio of the main peak of the scattering cross section is calculated. The calculation results are shown in Table 5.

[0106] [Table 6] EXAMPLES

[0107] In Example 7, in the model of the configuration of Figure 21, an aluminum plate with a thickness of 1 mm and a width of 50 mm is used as the bridge electrode, and a polystyrene frame with a thickness of 7.5 mm and a width of 50 mm is placed on the outside. The frequency of the incident electromagnetic wave is 3.8 GHz. The incident angle is changed from 0° to 60° in 10° increments, and the intensity ratio of the main peak of the scattering cross section is calculated. The calculation results are shown in Table 7.

[0108] [Table 7]

[0109] <Reference example 1> FIG. 24 shows a simulation model of Reference Example 1. In Reference Example 1, the panels are connected with an aluminum frame. The thickness T of the aluminum frame is 10 mm, and the width W is 50 mm. The frequency of the incident electromagnetic wave is 3.8 GHz. The incident angle is changed from 0° to 60° in 10° increments, and the intensity ratio of the main peak of the scattering cross section is calculated. The calculation results are shown in Table 8.

[0110] [Table 8]

[0111] <Reference example 2> FIG. 25 shows a simulation model of Reference Example 2. In Reference Example 2, the panels are connected with a shaped aluminum frame. The aluminum frame has a thickness T of 20 mm and a width W of 50 mm, and a notch is provided in the thickness direction. The frequency of the incident electromagnetic wave is 3.8 GHz. The incident angle is changed from 0° to 60° in 10° increments to calculate the intensity ratio of the main peak of the scattering cross section. The calculation results are shown in Table 9.

[0112] [Table 9] EXAMPLES

[0113] In Example 8, the configuration for connecting the panels is the same as in Example 1, and the frequency of the incident electromagnetic wave is 28 GHz. By setting the frequency of the electromagnetic wave to 28 GHz, the size of the analysis space is set to 100 mm x 200 mm x 200 mm. An aluminum plate with a thickness of 1 mm and a width of 50 mm is used as a bridge electrode, and an FRP frame with a thickness of 5 mm and a width of 50 mm is placed on the outside of the aluminum plate. The radius of curvature R of the corner of the frame is 2 mm. The incident angle of the 28 GHz electromagnetic wave is changed from 0° to 60° in 10° increments, and the intensity ratio of the main peak of the scattering cross section is calculated. The calculation results are shown in Table 10.

[0114] [Table 10]

[0115] <Reference example 3> In Reference Example 3, in the configuration of Figure 24, the thickness T of the aluminum frame is 8.5 mm, the width is 50 mm, and the frequency of the incident electromagnetic wave is 28 GHz. The incident angle is changed from 0° to 60° in 10° increments to calculate the intensity ratio of the main peak of the scattering cross section. The calculation results are shown in Table 11.

[0116] [Table 11]

[0117] <Reference example 4> In Reference Example 4, an aluminum frame having the configuration shown in FIG. 25 is used, and the frequency of the incident electromagnetic wave is set to 28 GHz. The incident angle is changed from 0° to 60° in increments of 10°, and the intensity ratio of the main peak of the scattering cross section is calculated. The calculation results are shown in Table 12.

[0118] [Table 12]

[0119] <Reference example 5> In Reference Example 5, two panels are arranged in the same YZ plane (see FIG. 20A) with a gap of 10 mm between them, without a frame that physically supports the panels or an electrical connection (or bridge electrode). The frequency of the incident electromagnetic wave is set to 3.8 GHz, and the size of the analysis space is set to 150 mm x 500 mm x 500 mm. The incidence angle is changed from 0° to 60° in 10° increments to calculate the intensity ratio of the main peak of the scattering cross section. The calculation results are shown in Table 13.

[0120] [Table 13]

[0121] <Reference example 6> In Reference Example 6, the panels are arranged in the same YZ plane (see FIG. 20A) with a gap of 50 mm in width between them, without a frame that physically supports the panels or an electrical connection (or bridge electrode). The frequency of the incident electromagnetic wave is set to 3.8 GHz, and the incidence angle is changed from 0° to 60° in 10° increments to calculate the intensity ratio of the main peak of the scattering cross section. The calculation results are shown in Table 14.

[0122] [Table 14]

[0123] FIG. 26 is a diagram showing reflection characteristics according to the presence or absence of connection between panels. The width of the gap between two panels arranged on the same plane is changed to 0 mm, 10 mm, 30 mm, 50 mm, 70 mm, and 90 mm. A gap width of 0 mm corresponds to arranging the panels without a gap, or using a single huge panel. A gap width of 10 mm corresponds to Reference Example 5, and a gap width of 50 mm corresponds to Reference Example 6. Example 1 is a configuration in which two panels are connected by a bridge electrode and FRP is used for the frame. Reference Example 1 is a configuration in which an aluminum frame is used.

[0124] From the results of FIG. 26, when the incident angle is in the range of 0° or more and 50° or less, if the gap between the panels is 10 mm or more, the reflection characteristics are inferior to the configuration of Example 1. On the other hand, from the viewpoint of strength, it is difficult to arrange the panels without gaps without a connecting structure. When the panels are made to stand on their own in a process line or the like and installed without gaps, only the bottom ends of the panels support the panels. The reflectance changes not only in terms of the ability to stand on their own and strength, but also depending on the deflection of the panel 13 and the inclination relative to other panel surfaces. It is difficult to manufacture and transport a single huge panel.

[0125] By using the connection structure of the embodiment, that is, the support 11 having the electrical connection portion 15, deterioration of the reflection characteristics can be suppressed and a plurality of panels can be arranged in a self-supporting manner.

[0126] Fig. 27 shows an example of a method for assembling the bridge electrode and the frame. The bridge electrode and the frame can be assembled by methods such as insert molding, full adhesion, partial adhesion, screw fastening, etc. to form a support. The frame 111 and the bridge electrode 112 can be integrally formed by insert molding. Since it is only necessary to make the reflective potential surface continuous between adjacent panels 13, the bridge electrode 112 may be provided on at least one of the two opposing inner walls of the frame 111, which has an H-shaped horizontal cross section.

[0127] The bridge electrode may be entirely bonded to the frame. When using a bridge electrode 173 having an H-shaped horizontal cross section as shown in FIG. 10G, adhesive 174 may be applied to the entire outer surface 173a (see FIG. 10G) of the bridge electrode 173, and the bridge electrode 173 may be bonded to the first portion 111a and the second portion 111b of the frame 111. When the bridge electrode 112 is disposed only on one inner wall of the frame, the bridge electrode 112 may be bonded with adhesive 174 between the first portion 111c of the frame having a T-shaped horizontal cross section and the second portion 111b of the frame having an I-shaped horizontal cross section.

[0128] The bridge electrode may be partially bonded to the frame. When a bridge electrode 173 having an H-shaped horizontal cross section is used, a plurality of through holes 175 may be provided along the height direction of the bridge electrode 173, and the through holes 175 may be filled with adhesive 174 to partially bond the bridge electrode 173 to the first portion 111a and the second portion 111b of the frame 111.

[0129] The first part 111a and the second part 111b of the frame may be screwed together with conductive screws 138. The screws 138 hold the panel between the first part 111a and the second part 111b of the frame, and also make the reflective potential surface between adjacent panels continuous through the screws 138. In this case, it is desirable to irradiate the electromagnetic wave onto the surface without the screws.

[0130] Either method can be used to manufacture a support 11 having electrical connection parts 15 (see FIGS. 10A to 10G).

[0131] <Application to process lines> FIG. 28 is a diagram explaining the size of the meta-reflector 102. The transmitter is designated as "Tx" and the receiver is designated as "Rx." The transmitter Tx is, for example, a base station BS. The receiver Rx is, for example, a device in the process line 3. The distance from the transmitter Ts to the surface 102S of the meta-reflector 102 is designated as d1, and the distance from the surface 102S of the meta-reflector 102 to the receiver Rx is designated as d2.

[0132] Assuming use in a process line, the total distance D of d1 and d2 is, for example, 40 m (D = d1 + d2 = 40 m). The standard length of a process line is 80 m. Assuming that base stations BS are placed at both ends of the process line in the longitudinal direction and that the two base stations BS provide a standard rectangular service area, D = 40 m.

[0133] The radius R of the first Fresnel zone when the radio waves emitted from the transmitter Tx and reflected by the meta-reflector 102 reach the receiver Rx in phase is defined by the formula (1).

[0134]

number

[0135] Figure 29 shows a specific example of the radius R of the first Fresnel zone derived from equation (1). When the operating frequency is 28 GHz, d1 is 30 m, and d2 is 10 m, the radius R of the first Fresnel zone is 0.283 m. When d1 is 35 m and d2 is 5 m at the same frequency, the radius R is 0.216 m.

[0136] When the operating frequency is 3.8 GHz, d1 is 30 m, and d2 is 10 m, the radius R of the first Fresnel zone is 0.770 m. When d1 is 35 m and d2 is 5 m at the same frequency, the radius R is 0.588.

[0137] It is desirable for the device M arranged in the process line to be able to receive the reflected wave from the electromagnetic wave reflecting device 10 in phase with the direct wave from the base station BS to improve the reception strength. When the electromagnetic wave reflecting device 10 using the meta-reflector 102 is applied to the process line, in consideration of the first Fresnel zone where in-phase reception is possible, it is desirable for the minimum size of one meta-reflector 102 to be at least 0.5 m on one side in the 28 GHz band. In the 3.8 GHz band, it is desirable for the minimum size of one meta-reflector 102 to be about 1 m on one side. As shown in Figs. 5B to 5D, even when multiple meta-reflectors 102 are used on one panel 13, it is desirable for the size of each meta-reflector 102 to cover at least the first Fresnel zone.

[0138] Since the radius R of the first Fresnel zone does not depend on the relationship between the angle of incidence and the angle of reflection, a similar calculation can be applied to the normal reflector 101. In order to guide the radio waves incident on the normal reflector 101 to the receiver Rx by regular reflection while maintaining the same phase, it is desirable for the size of the normal reflector 101 to have one side of 50 cm or more.

[0139] When the metareflector 102 is used in a process line covered by a service area with a large aspect ratio, the oblique incidence of either the incident angle or the reflection angle becomes deep. The layout relationship between the process line 3, the base station BS, and the electromagnetic wave reflecting device 10 will be considered below.

[0140] <Layout of wireless transmission systems> The layout relationship of the wireless transmission system 1 will be described with reference to Figures 30A, 30B, 31A, and 31B. As described with reference to Figures 1 and 2, the wireless transmission system 1 includes a base station BS that transmits and receives radio waves in the 1 GHz to 170 GHz band, a process line 3 in which production equipment that transmits and receives the radio waves is disposed, and an electromagnetic wave reflecting device 10 that is disposed along at least a portion of the process line. The electromagnetic wave reflecting device 10 has a reflecting surface 105 that reflects radio waves in the above band.

[0141] As described in detail below, it is desirable to position the base station BS on the process line 3 side of an extension line L horizontal to the reflecting surface 105. For example, the base station BS may be disposed at both ends in the longitudinal direction of the process line 3. The production equipment in the process line 3 can communicate with the base station BS directly or via the electromagnetic wave reflecting device 10 in the above-mentioned band.

[0142] 30A shows reflection pattern 1 in the wireless transmission system 1. In pattern 1, as shown by the solid arrow, the base station BS and the process line 3 are arranged in a positional relationship in which the radio wave radiated from the base station BS is incident at a deep angle with respect to the perpendicular to the reflecting surface 105 of the electromagnetic wave reflecting device 10 and is reflected at a shallow angle. That is, in pattern 1, the radio wave is incident at an incident angle of 45 degrees or more and is reflected so that the reflection angle is smaller than the reflection angle in regular reflection.

[0143] To make the radio waves from the base station BS incident on the reflecting surface 105 at a deep angle, the base station BS is preferably located closer to the process line 3 than the extension line L of the electromagnetic wave reflecting device 10 and at an end in the longitudinal direction of the process line 3. By making the radio waves incident on the reflecting surface 105 at a deep angle, the radio waves can be sent to the center of the process line 3 or its vicinity.

[0144] 30B shows reflection pattern 2. In pattern 2, the base station BS and the process line 3 are disposed in a positional relationship in which the radio waves emitted from the base station BS are incident at a shallow angle with respect to the perpendicular line of the reflecting surface 105, and are reflected at an angle deeper than the incident angle. That is, in pattern 2, the radio waves are incident at an incident angle of 45 degrees or less, and are reflected so that the reflection angle is larger than the reflection angle in regular reflection.

[0145] In the case of pattern 2, the base station BS is located on the process line 3 side of the extension line L horizontal to the reflecting surface 105 of the electromagnetic wave reflecting device 10, but is located closer to the center than to the end in the longitudinal direction of the process line 3. As will be described below, in the case of pattern 2, the effect of the variation in the oblique incidence angle becomes large.

[0146] Fig. 31A shows the reference robustness of Pattern 1, and Fig. 31B shows the reference robustness of Pattern 2. The reference robustness refers to the stability of the reflection angle when the incidence angle is changed by 1 degree. When the change in the reflection angle is small for a change in the incidence angle of 1 degree, the reference robustness is high.

[0147] 31A, the abnormal angle θabn is changed to seven different angles, 20°, 25°, 30°, 35°, 40°, 45°, and 50°, in pattern 1, and the variation in the reflection angle relative to the change in the incident angle is estimated. The variation in the reflection angle at the seven abnormal angles θabn is almost the same and overlaps with each other, so it is shown as a single thick line in the figure.

[0148] As described with reference to Fig. 3B, the abnormal angle θabn is the difference between the reflection angle due to regular reflection and the reflection angle due to asymmetric reflection in which a radio wave is reflected at a reflection angle different from the angle of incidence. Changing the abnormal angle θabn from 20° to 50° corresponds to controlling the reflection direction of the asymmetric reflection over an angle range of 30 degrees.

[0149] When the angle of incidence is in the range of 50° to 75° (deep incidence), the change in the angle of reflection for a change in the angle of incidence of 1° is small, less than 1°, and is almost constant regardless of the angle of incidence. It can be seen that when the angle of incidence is deep, the controllability of reflection in asymmetric reflection is high. It can be easily assumed that the tendency in FIG. 17A, which shows that the change in the angle of reflection is small, is maintained even when the angle of incidence exceeds 75° and approaches 90°.

[0150] 31B, the abnormal angle θabn is changed to seven different angles, 20°, 25°, 30°, 35°, 40°, 45°, and 50°, to estimate the variation in the reflection angle relative to the incident angle in pattern 2. In the incident angle range of 15° to 40° (shallow reflection), the variation in the reflection angle relative to a 1-degree change in the incident angle varies depending on the incident angle and varies greatly depending on the abnormal angle θabn.

[0151] When the abnormal angle θabn is small, that is, when the difference from the reflection angle of regular reflection is small, the incidence angle dependence of the variation in the reflection angle is small. When the abnormal angle θabn is large, that is, when the change in the reflection direction by the metareflector 102 is large, the variation in the reflection angle per 1 degree of the incidence angle becomes very large, and the amount of variation in the reflection angle also differs greatly depending on the incidence angle. When the incidence angle is in the shallow range of 15° to 40°, the controllability of the reflection in asymmetric reflection is not good.

[0152] 31A and 31B, when arranging the base station BS in the process line 3, it is preferable to arrange the base station BS at a position where the angle of incidence on the reflecting surface 105 of the electromagnetic wave reflecting device 10 is 50° or more, from the viewpoint of suppressing the fluctuation of the reflection angle depending on the angle of incidence. Therefore, the arrangement shown in Fig. 30A is more preferable than the arrangement shown in Fig. 30B.

[0153] FIG. 32 is a diagram for explaining a method for quantifying the criterion robustness. The criterion robustness in FIG. 31A and FIG. 31B is estimated by the following procedure. A certain angle of incidence θi and angle of reflection θr are input, and a phase jump Φ(x) is calculated using a 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 added to the reflected wave in order to reflect the reflected wave at a desired angle. The phase jump distribution dΦ / dx is expressed as follows: sinθr-sinθi=(λ / 2π)(dΦ / dx) Here, λ is the wavelength used. Using the surface impedance ZS and wave impedance η described in the non-patent document, PHYSICAL REVIEW B 94.075142 (2016), VS Asadchy, et al., "PERFECT CONTROL OF REFLECTION AND REFRACTION USING SPATIALLY DISPERSIVE METASURFACES," the function f for calculating the phase jump distribution Φ(x) is given by

[0154]

number

[0155]

number

[0156] Next, the incident angle is changed by 1 degree, and the incident angle and reflection angle 'after the change are input to calculate the phase jump Φ'(x) from the phase jump distribution function f.

[0157] The reflection angle' at which Φ'(x)-Φ(x) is minimum is found, and this is regarded as the variation of the reflection angle with respect to the incident angle. Figures 31A and 31B show plots of the variation of the reflection angle found as a function of the incident angle.

[0158] Figure 33A shows the change in phase jump for pattern 1. The horizontal axis is position (m) and the vertical axis is phase (degrees). In the Deep-in Shallow-out case in Figure 33A, the reflection angle θr is fixed at 30 degrees, and the incidence angle θi is varied to 68.5°, 70°, and 71.5°. At deep angles of incidence, the distribution of phase jumps does not change significantly even if the incidence angle is changed within a range of 3°.

[0159] Figure 33B shows the change in phase jump for pattern 2. The horizontal axis is position (m) and the vertical axis is phase (degrees). In the shallow-in deep-out of Figure 33B, the reflection angle θr is fixed at 60 degrees, and the incidence angle θi is varied between 18.5°, 20°, and 21.5°. In the case of shallow incidence, when the incidence angle is changed in a range of 3° as in Figure 33A, the distribution of phase jumps shifts significantly depending on the incidence angle.

[0160] 33A and 33B also show that the arrangement in Fig. 30A is more preferable than Fig. 30B in terms of making uniform the phase jump of the radio waves incident on the electromagnetic wave reflecting device 10. In the arrangement in Fig. 30B, the base station BS is placed at a position where the 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 50 degrees or more.

[0161] Although the present invention has been described above based on specific configuration examples, various modifications and substitutions are possible without departing from the scope of the invention. The meta-reflector 102 may adopt any configuration as long as it can control reflection characteristics such as the reflection phase, and a periodic structure having frequency selectivity or wavelength selectivity may be appropriately designed. In some or all of the above configuration examples, the surface of the bridge electrode may be insulated coated.

[0162] The electromagnetic wave reflecting device 10 may be disposed on one side along the long side of the process line 3 as in Fig. 30A, or may be disposed on both sides of the process line 3 as in Fig. 2. If the process line 3 is curved like an L-shape, the electromagnetic wave reflecting device 10 may be installed in each area forming a rectangular area, or the electromagnetic wave reflecting device 10 may be installed on any of the main lines. In either case, the base station BS is disposed at a position where radio waves are incident on the reflecting surface 105 of the electromagnetic wave reflecting device 10 at a deep incident angle.

[0163] The devices in the process line 3 do not necessarily need to receive only the reflected waves from the electromagnetic wave reflecting device 10, but may directly receive the radio waves emitted from the base station BS. In this case, receive diversity may be achieved by in-phase reception. When base stations BS are arranged on both sides of the process line 3 in the longitudinal direction, a cooperative base station may be used.

[0164] Each electromagnetic wave reflecting device 10 may be transported with the frame 111 attached to one of the opposing edges of the panel 13 and the guide beam 118 attached to the other, as shown in Fig. 11A. In this case, the work of attaching parts on site is omitted, and assembly is facilitated. Alternatively, the panel 13 may be transported with only the frame 111 attached, and assembled on site using the guide beam 118. Also, as shown in Fig. 5A, the positioning of the metasurface on the panel 13 may be performed at the installation site of the electromagnetic wave reflecting device 10.

[0165] The electromagnetic wave reflecting device and wireless transmission system of the embodiment contribute to the realization of smart factories.

[0166] This application claims priority based on Japanese Patent Application No. 2020-064577, filed on March 31, 2020, and Japanese Patent Application No. 2020-173308, filed on October 14, 2020, and includes the entire contents of these patent applications. [Explanation of symbols]

[0167] 1. Radio Transmission System 3. Process Line 10, 10A~10G, 10-1, 10-2 Electromagnetic wave reflector 11 Support Panels 13, 13-1, and 13-2 15,15A~15E Connection 16 Rod 17, 17-1, 17-2 Edge Jacket 19 Bracing 100 Electromagnetic Wave Reflecting Fence 101 Normal reflector 102 Metal Reflector 105 Reflective surface 111, 111A~111G Frame 112, 112A, 112a, 112b, 114, 173 Bridge electrodes 118 Guide Beam 125 Reinforcement mechanism 131 Conductor 132, 133 Dielectrics BS, BS1, BS2 base station WT, WT1, WT2 Wireless communication section SY Symmetrical reflection area AS Asymmetric reflection area

Claims

1. A plurality of panels each having a reflective surface that reflects radio waves in a desired band selected from a frequency band of 1 GHz to 170 GHz; A support that connects and supports the plurality of panels; Equipped with The support is A frame that connects and supports the plurality of panels; a connection portion provided on the frame and electrically connecting the reflective surfaces of the plurality of panels; having The connection portion is a conductive edge jacket that grips the edges of each of the adjacent panels; a conductive bridge electrically connecting the conductive edge jackets gripping the edges of each of the adjacent panels; having The width of the conductive bridge is 100 mm or less. Electromagnetic wave reflector.

2. A plurality of panels each having a reflective surface that reflects radio waves in a desired band selected from a frequency band of 1 GHz to 170 GHz; A support that connects and supports the plurality of panels; Equipped with The support is A frame that connects and supports the plurality of panels; a connection portion provided on the frame and electrically connecting the reflective surfaces of the plurality of panels; having The connection portion is a conductive edge jacket for gripping the edges of each of the adjacent panels; the frame is made of a conductor and electrically connects the conductive edge jackets that grip the edges of each of the adjacent panels; The width of the frame is 150 mm or less. Electromagnetic wave reflector.

3. 3. The electromagnetic wave reflecting device according to claim 1, wherein the connecting portion has a conductive material portion that electrically connects the reflecting surfaces of the plurality of panels.

4. the reflective surface of the panel is a surface of a conductor; The electromagnetic wave reflecting device according to claim 1 , wherein the connection portion electrically connects the conductors of the plurality of panels.

5. 5. The electromagnetic wave reflection device according to claim 1, wherein the reflection surface has a symmetric reflection area that reflects an incident radio wave at a reflection angle that is the same as the incident angle, and an asymmetric reflection area that reflects an incident radio wave at a reflection angle different from the incident angle.

6. The asymmetric reflection region includes a diffusion region that reflects the incident radio wave with a predetermined angular distribution.

6. The electromagnetic wave reflecting device according to claim 5.

7. 7. The electromagnetic wave reflecting device according to claim 5, wherein the area of ​​the asymmetric reflecting region covers at least a first Fresnel zone determined by the frequency of the radio wave.

8. 8. The electromagnetic wave reflecting device according to claim 5, wherein the asymmetric reflecting area is attached to a moving member that is movable on the surface of the panel.

9. The electromagnetic wave reflection device according to any one of claims 1 to 8, wherein the reflection surface has a mesh, lattice, or hole array formed at a density that reflects radio waves in the band, and the average period of the mesh, lattice, or hole array formed at the density is 1 / 5 or less of the free space wavelength of the band.

10. At least a portion of the panel is transparent to visible light; The electromagnetic wave reflecting device according to any one of claims 1 to 9.

11. The support has a base that allows the panel to stand upright on an installation surface. The electromagnetic wave reflecting device according to any one of claims 1 to 10.

12. An electromagnetic wave reflecting fence comprising a plurality of electromagnetic wave reflecting devices according to any one of claims 1 to 11 connected by the support body.

13. 13. The electromagnetic wave reflecting fence according to claim 12, further comprising a reinforcing mechanism for reinforcing electrical connection by said connecting portions between adjacent said electromagnetic wave reflecting devices.

14. a first panel having a first reflective surface that reflects radio waves in a desired band selected from a frequency band of 1 GHz to 170 GHz, and a second panel having a second reflective surface that reflects radio waves in the desired band, said first panel being mechanically connected by a support; an electrical connection portion provided on the support electrically connects the first reflecting surface and the second reflecting surface; The electrical connection portion is a conductive edge jacket gripping an edge of each of the first panel and the second panel; a conductive bridge electrically connecting the conductive edge jackets that grip the edges of the first and second panels; having The width of the conductive bridge is 100 mm or less. A method for assembling an electromagnetic wave reflecting device.

15. a first panel having a first reflective surface that reflects radio waves in a desired band selected from a frequency band of 1 GHz to 170 GHz, and a second panel having a second reflective surface that reflects radio waves in the desired band, said first panel being mechanically connected by a support; an electrical connection portion provided on the support electrically connects the first reflecting surface and the second reflecting surface; The support body has a frame that connects and supports the first panel and the second panel, The electrical connection portion is a conductive edge jacket that grips an edge of each of the first panel and the second panel; the frame is made of a conductor and electrically connects the conductive edge jackets that grip the edges of the first panel and the second panel; The width of the frame is 150 mm or less. A method for assembling an electromagnetic wave reflecting device.

16. At least one of the first panel and the second panel has a metasurface with controlled reflection characteristics on the first reflecting surface or the second reflecting surface, positioning the metasurface on a panel at the installation site of the electromagnetic wave reflecting device; A method for assembling the electromagnetic wave reflecting device according to claim 14 or 15.

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