Communication system and installation method for radio wave control plate

Abstract

A communication system comprising a first radio wave control plate and a second radio wave control plate, wherein the first radio wave control plate deflects or reflects radio waves transmitted from a transmission device in the direction of the second radio wave control plate, and the second radio wave control plate deflects or reflects the radio waves emitted from the first radio wave control plate in the direction of a reception device or the direction of a third radio wave control plate.

Description

Communication system and radio wave control board installation method

[0001] The present disclosure relates to a communication system and a method for installing a radio wave control panel.

[0002] There are known techniques for controlling electromagnetic waves without using a dielectric lens. For example, Patent Document 1 describes a technique for refracting radio waves by changing the parameters of each element in a structure in which resonator elements are arranged.

[0003] JP 2015-231182 A

[0004] The communication system of the present disclosure includes a first radio wave control plate and a second radio wave control plate, wherein the first radio wave control plate refracts or reflects radio waves transmitted from a transmitting device toward the second radio wave control plate, and the second radio wave control plate refracts or reflects radio waves emitted from the first radio wave control plate toward a receiving device or a third radio wave control plate.

[0005] The method for installing a radio wave control plate disclosed herein includes a step of installing a first radio wave control plate at a first installation position so that radio waves transmitted by a transmitting device are refracted or reflected in the direction of a second radio wave control plate, and a step of installing the second radio wave control plate at a second installation position so that radio waves emitted from the first radio wave control plate are refracted or reflected in the direction of a receiving device or a third radio wave control plate.

[0006] FIG. 1 is a diagram for explaining an overview of a radio wave control plate. FIG. 2 is a diagram for explaining the transmission direction of radio waves through a radio wave control plate. FIG. 3 is a diagram for explaining a communication system according to a comparative example. FIG. 4 is a diagram for explaining a configuration example of a communication system according to a first example of the first embodiment. FIG. 5 is a diagram for explaining a configuration example of a communication system according to a second example of the first embodiment. FIG. 6 is a diagram for explaining a configuration example of a communication system according to a third example of the first embodiment. FIG. 7 is a diagram for explaining a method for setting the size of a radio wave control plate according to a second embodiment. FIG. 8 is a diagram showing the relationship between the size of the radio wave control plate and the received power of the radio wave control plate according to the second embodiment. FIG. 9 is a diagram for explaining the effective range of the refraction angle of a radio wave control band according to a third embodiment. FIG. 10 is a diagram for explaining the beam pattern of a radio wave control plate according to the third embodiment.

[0007] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to this embodiment, and in the following embodiments, the same components are designated by the same reference numerals, and redundant explanations will be omitted.

[0008] In the following description, an XYZ Cartesian coordinate system is set, and the positional relationship of each part will be described with reference to this XYZ Cartesian coordinate system. The direction parallel to the X axis in a horizontal plane is defined as the X-axis direction, the direction parallel to the Y axis in the horizontal plane perpendicular to the X axis is defined as the Y-axis direction, and the direction parallel to the Z axis perpendicular to the horizontal plane is defined as the Z-axis direction. Furthermore, the plane including the X axis and Y axis will be referred to as the XY plane as appropriate, the plane including the X axis and Z axis will be referred to as the XZ plane as appropriate, and the plane including the Y axis and Z axis will be referred to as the YZ plane as appropriate. The XY plane is parallel to the horizontal plane. The XY plane, XZ plane, and YZ plane are perpendicular to each other.

[0009] [Outline] (Radio wave control board) An outline of the radio wave control board will be described with reference to Fig. 1. Fig. 1 is a diagram for explaining the outline of the radio wave control board.

[0010] The radio wave control board 1 is a plate-like member configured to be able to reflect or refract radio waves transmitted from a base station. For example, when receiving radio waves transmitted from a base station, the radio wave control board 1 is configured to reflect or refract the radio waves at a predetermined angle. The radio wave control board 1 can be configured, for example, from a metamaterial that changes the phase of the incident wave.

[0011] 1, radio wave control board 1 may include, for example, substrate 2 and unit structures 10a, 10b, 10c, and 10d. When there is no need to distinguish between unit structures 10a to 10d, they will be collectively referred to as unit structures 10.

[0012] The unit structures 10a, 10b, 10c, and 10d may be formed on a substrate 2. The substrate 2 may be, for example, a dielectric substrate made of a dielectric material. The substrate 2 may have, for example, but is not limited to, a rectangular shape. The unit structures 10a, 10b, 10c, and 10d may be arranged two-dimensionally.

[0013] In the radio wave control board 1, a plurality of unit structures 10a are arranged along the X-axis direction on one tier. A plurality of unit structures 10b are arranged along the X-axis direction on the tier above the tier on which unit structures 10a are arranged. A plurality of unit structures 10c are arranged along the X-axis direction on the tier above the tier on which unit structures 10b are arranged. A plurality of unit structures 10d are arranged along the X-axis direction on the tier above the tier on which unit structures 10c are installed. In the example shown in FIG. 1 , unit structures 10a, unit structures 10b, unit structures 10c, and unit structures 10d are arranged periodically along the Y-axis direction.

[0014] Unit structure 10a, unit structure 10b, unit structure 10c, and unit structure 10d are all different in size. In the example shown in Fig. 1, unit structure 10a is the largest, followed by unit structure 10b, unit structure 10c, and unit structure 10d in order of size. That is, radio wave control board 1 has a structure in which a plurality of unit structures 10 of different sizes are periodically arranged.

[0015] The unit structures 10a to 10d may each have a different amount of phase change in the received radio waves. That is, the unit structures 10a to 10d are periodically arranged so as to have a gradient in the amount of phase change. The unit structures 10a to 10d each have a rectangular shape, but are not limited to this. By changing the size and shape of the unit structures 10a to 10d, the frequency band and amount of phase change of the radio waves to be reflected or refracted can be adjusted.

[0016] FIG. 2 is a diagram illustrating the refraction direction of radio waves of a radio wave control board. Radio wave control board 1 shown in FIG. 2 is a refraction-type radio wave control board that refracts received radio waves at a predetermined angle and emits them. For example, when radio wave control board 1 receives radio waves 31 transmitted from transmitting device 20, it emits refracted waves 32 that have been refracted in a predetermined direction. Range R indicates the range over which radio waves can be refracted by radio wave control board 1. Radio wave control board 1 cannot refract radio waves 31 by more than 90° relative to the direction of travel. Transmitting device 20 is, for example, a base station, but is not limited to this.

[0017] FIG. 3 is a diagram illustrating a communication system according to a comparative example. The communication system 1000a includes a radio wave control board 1, a transmitting device 20, and a receiving device 21. The receiving device 21 may be, but is not limited to, a relay device that relays radio waves or a terminal device such as a smartphone used by a user. Obstacles 41 and 42 are located around the transmitting device 20 and the receiving device 21, blocking the radio waves 31 transmitted by the transmitting device 20. Therefore, line of sight between the transmitting device 20 and the receiving device 21 is not ensured, making it difficult for the transmitting device 20 and the receiving device 21 to communicate directly. In such an environment, if an attempt is made to communicate between the transmitting device 20 and the receiving device 21 using the radio wave control board 1, the receiving device 21 may be unable to receive the refracted wave 32 resulting from the radio wave 31 refracted by the radio wave control board 1 because it is located near the obstacle 42. Therefore, in the first embodiment, a communication system is configured that allows appropriate communication between the transmitting device 20 and the receiving device 21 even in an environment where radio wave visibility is not ensured between the transmitting device 20 and the receiving device 21.

[0018] [First embodiment] (Communication system) (First example) A communication system according to a first example of the first embodiment will be described with reference to Fig. 4. Fig. 4 is a diagram showing an example of the configuration of a communication system according to the first example of the first embodiment.

[0019] As shown in Fig. 4, the communication system 1000 includes a first radio wave control board 1-1, a second radio wave control board 1-2, a transmitting device 20, and a receiving device 21. Obstacles 43 and 44 that block radio waves are located around the transmitting device 20 and the receiving device 21. In the example shown in Fig. 4, the receiving device 21 is located between the obstacles 43 and 44. Therefore, line of sight of radio waves is not ensured between the transmitting device 20 and the receiving device 21.

[0020] The first radio wave control board 1-1 is placed at a first installation position where it can receive radio waves 31 transmitted by the transmitting device 20. The first radio wave control board 1-1 is a refractive radio wave control board that refracts the received radio waves at a predetermined angle and then emits the refracted waves 32. The first radio wave control board 1-1 refracts the radio waves 31 at a predetermined angle and emits the refracted waves 32.

[0021] The second radio wave control board 1-2 is disposed at a second installation position where it can receive the refracted wave 32 emitted by the first radio wave control board 1-1. The second radio wave control board 1-2 is a refractive radio wave control board that refracts the received radio wave at a predetermined angle and emits the refracted wave 33. The second radio wave control board 1-2 refracts the refracted wave 32 in the direction of the receiving device 21 and emits the refracted wave 33.

[0022] The receiving device 21 receives the refracted wave 33 emitted by the second radio wave control board 1-2. That is, the transmitting device 20 and the receiving device 21 can communicate via the first radio wave control board 1-1 and the second radio wave control board 1-2. The first radio wave control board 1-1 and the second radio wave control board 1-2 bend the radio waves 31 transmitted by the transmitting device 20 by 90 degrees relative to the direction of travel of the radio waves 31, thereby ensuring line of sight of the radio waves between the transmitting device 20 and the receiving device 21. This allows the transmitting device 20 and the receiving device 21 to communicate appropriately.

[0023] In addition, in the example shown in Figure 4, by controlling the refraction angle of the refracted wave 32 of the second radio wave control plate 1-2, it is also possible to bend the radio wave 31 transmitted by the transmitting device 20 by more than 90 degrees relative to the direction of travel of the radio wave 31.

[0024] (Second Example) A communication system according to a second example of the first embodiment will be described with reference to Fig. 5. Fig. 5 is a diagram showing an example of the configuration of a communication system according to the second example of the first embodiment.

[0025] As shown in Fig. 5, communication system 1000A includes first radio wave control board 1-1, second radio wave control board 1-2, transmitting device 20, and receiving device 21. Obstacles 45 and 46 that block radio waves are located around transmitting device 20 and receiving device 21. In the example shown in Fig. 5, receiving device 21 is located behind obstacles 45 and 46 as seen from transmitting device 20. Therefore, line of sight of radio waves is not ensured between transmitting device 20 and receiving device 21.

[0026] 5, the first radio wave control board 1-1 is also placed at a first installation position where it can receive radio waves 31 transmitted by the transmitting device 20. The first radio wave control board 1-1 refracts the radio waves 31 at a predetermined angle and emits a refracted wave 32. The second radio wave control board 1-2 is placed at a second installation position where it can receive the refracted wave 32 emitted by the first radio wave control board 1-1. The first radio wave control board 1-1 refracts the refracted wave 32 in the direction of the receiving device 21 and emits a refracted wave 33. The receiving device 21 receives the refracted wave 33 emitted by the second radio wave control board 1-2.

[0027] 5, by adjusting the installation positions and refraction angles of the first radio wave control board 1-1 and the second radio wave control board 1-2, it is possible to ensure line of sight of radio waves between the transmitting device 20 and the receiving device 21. This allows the transmitting device 20 and the receiving device 21 to communicate appropriately.

[0028] (Third Example) A communication system according to a third example of the first embodiment will be described with reference to Fig. 6. Fig. 6 is a diagram showing an example of the configuration of a communication system according to the third example of the first embodiment.

[0029] As shown in Fig. 6, the communication system 1000B includes a first radio wave control board 1-1, a second radio wave control board 1-2, a transmitting device 20, and a receiving device 21. Obstacles 47 and 48 that block radio waves are located around the transmitting device 20 and the receiving device 21. In the example shown in Fig. 6, the receiving device 21 is located in a location surrounded by the obstacles 47 and 48. Therefore, line of sight of radio waves is not ensured between the transmitting device 20 and the receiving device 21.

[0030] 6, the first radio wave control board 1-1 is also placed at a first installation position where it can receive radio waves 31 transmitted by the transmitting device 20. The first radio wave control board 1-1 refracts the radio waves 31 at a predetermined angle and emits refracted waves 32.

[0031] Second radio wave control board 1-2 is disposed at a second installation position where it can receive refracted wave 32 emitted by first radio wave control board 1-1. In FIG. 6, second radio wave control board 1-2 is a reflective radio wave control board that reflects the received radio wave at a predetermined angle and emits the reflected wave 34. In other words, communication system 1000B includes a refracted radio wave control board and a reflective radio wave control board. Second radio wave control board 1-2 reflects refracted wave 32 in the direction of receiving device 21 and emits reflected wave 34.

[0032] The receiving device 21 receives the reflected wave 34 emitted by the second radio wave control board 1-2. That is, the transmitting device 20 and the receiving device 21 can communicate via the first radio wave control board 1-1 and the second radio wave control board 1-2. The first radio wave control board 1-1 and the second radio wave control board 1-2 refract and reflect the radio waves 31 transmitted by the transmitting device 20, thereby ensuring line of sight of the radio waves between the transmitting device 20 and the receiving device 21. This allows the transmitting device 20 and the receiving device 21 to communicate appropriately.

[0033] (Phase Distribution of Radio Wave Control Plate) The phase distribution of the radio wave control plate 1 according to the first embodiment will be described. As shown in FIG. 1, the radio wave control plate 1 includes a plurality of unit structures 10. The phase distribution of the radio wave control plate 1 provides a phase difference between adjacent unit structures 10 so as to change the direction of propagation of radio waves. If the phase difference between adjacent unit structures is ΔΦ, the angle of reflection or refraction when the angle of incidence is 0° (when radio waves are incident from the front of the radio wave control plate 1) is θ, the distance between adjacent unit structures 10 is d, and the wave number is k, then ΔΦ is preferably set to satisfy the following formula (1):

[0034]

[0035] The condition of equation (1) indicates the condition under which radio waves incident on radio wave control board 1 as plane waves reinforce each other at infinity after reflection or refraction. The condition for the phase distribution of radio wave control board 1 is not limited to the condition shown in equation (1). For example, in the example shown in FIG. 4 , the phase distribution of first radio wave control board 1-1 may be set so that refracted wave 32 emitted by first radio wave control board 1-1 converges at the position of second radio wave control board 1-2. The phase distribution of second radio wave control board 1-2 may also be set so that refracted wave 33 emitted by second radio wave control board 1-2 converges at the position of receiving device 21. Radio wave control board 1 may also have a phase distribution that does not have a convergence point, but rather widens the beam width of the incident plane wave after reflection or refraction.

[0036] Furthermore, in the first embodiment, two radio wave control plates 1 are used to ensure line-of-sight between the transmitting device 20 and the receiving device 21, but the present disclosure is not limited to this. In the present disclosure, three or more radio wave control plates 1 may be used to ensure line-of-sight between the transmitting device 20 and the receiving device 21. In the present disclosure, using three or more radio wave control plates 1 allows the radio waves transmitted by the transmitting device 20 to bend in various directions, thereby more appropriately ensuring line-of-sight between the transmitting device 20 and the receiving device 21 regardless of the relative positions of the transmitting device 20 and the receiving device 21. Here, it is preferable that the radio wave control plate 1 be capable of reflecting or refracting both horizontally polarized waves and vertically polarized waves (hereinafter also referred to as dual polarizations). This is because, when the transmitting device 20 transmits dual-polarized radio waves, a radio wave control plate capable of reflecting or refracting both polarized waves delivers more power to the receiving device 21 than a radio wave control plate capable of reflecting or refracting only one of horizontally polarized waves and vertically polarized waves. The same applies to the following embodiments.

[0037] [Second Embodiment] A second embodiment will be described. For example, when two radio wave control plates 1 are used to bend radio waves transmitted by transmitting device 20, receiving device 21 may not be able to receive effective power unless the size of radio wave control plate 1 (e.g., the length of one side) is appropriate for the distance between the two radio wave control plates 1. Therefore, in the second embodiment, the size of the radio wave control plate is appropriately configured.

[0038] (Size of radio wave control plate) The size of the radio wave control plate according to the second embodiment will be described with reference to Fig. 7. Fig. 7 is a diagram for explaining a method for setting the size of the radio wave control plate according to the second embodiment.

[0039] In the second embodiment, the size of the radio wave control plate 1 is set based on the Fresnel zone. Specifically, the size of the radio wave control plate 1 is set to be equal to or smaller than the first Fresnel radius.

[0040] In the example shown in FIG. 7 , center point C indicates the center point of radio wave control board 1. Transmission point T indicates the transmission point of radio waves. Reception point R indicates the reception point of the outgoing waves emitted from radio wave control board 1. Reception point R' indicates a virtual reception point. In the example shown in FIG. 7 , the straight-line distance between center point C and reception point R is the same as the straight-line distance between center point C and reception point R'. When considering the path from transmission point T through radio wave control board 1 to reception point R, radio wave control board 1 is installed in an area where radio waves reinforce each other. This enables the second embodiment to obtain higher received power. In this embodiment, the area where radio waves reinforce each other is called an odd-order Fresnel zone, and the area where radio waves destructively reinforce each other is called an even-order Fresnel zone.

[0041] As shown in Figure 7, consider the situation where radio waves from a transmitting point T pass through the radio wave control board 1 and reach a receiving point R. Let d be the linear distance between the transmitting point T and the center point C. ＴＭ The linear distance between the receiving point R and the center point C is d ＭＲ Let λ be the wavelength of the radio wave transmitted from transmitting point T. Consider a plane P that is perpendicular to the line connecting transmitting point T and receiving point R', passing through center point C. Now, consider a circle on plane P that is centered at center point C and has a radius r1 defined by the following equation (2).

[0042]

[0043] The circle of radius r1 defined by equation (2) is called the first Fresnel zone 50. Radius r1 is called the first Fresnel radius. In the example shown in FIG. 7 , the first Fresnel zone 50, the second Fresnel zone 52, the third Fresnel zone 54, and the fourth Fresnel zone 56 are shown. The first Fresnel zone 50 and the third Fresnel zone 54 are odd-order Fresnel zones. The second Fresnel zone 52 and the fourth Fresnel zone 56 are even-order Fresnel zones. In the second embodiment, the size of the radio wave control plate 1 is preferably equal to or greater than the first Fresnel radius.

[0044] 8 is a diagram showing the relationship between the size of the radio wave control board and the received power of the radio wave control board according to the second embodiment. Waveform 101 shown in FIG. 8 represents the result of calculating the received power of radio wave control board 1 having a side length of X [m] that satisfies formula (1) by changing X. The calculation conditions are a radio wave frequency of 28 [GHz (gigahertz)], an antenna gain at receiving point R (receiving device) of 0 [dBi (decibels)], and ＴＭ = 50 [m], d ＭＲ = 5 [m]. Under these conditions, the first Fresnel radius is calculated to be 0.22 [m] using equation (2). In FIG. 8, line 102 represents the first Fresnel radius. Line 103 represents the received power received at a linear distance of 55 [m] from transmission point T to reception point R' passing through center point C of radio wave control board 1. As shown by lines 102 and 103, the received power of radio wave control board 1 is equal to the received power received at a linear distance of 55 [m] from transmission point T to reception point R' passing through center point C of radio wave control board 1 when the size of radio wave control board 1 is the first Fresnel radius. In other words, it is preferable that the size of radio wave control board 1 be equal to or greater than the first Fresnel radius.

[0045] In the example shown in Figure 4, when viewed from the first radio wave control board 1-1, the transmitter 20 corresponds to the transmission point T, and the second radio wave control board 1-2 corresponds to the reception point R'. When viewed from the second radio wave control board 1-2, the first radio wave control board 1-1 corresponds to the transmission point T, and the receiver 21 corresponds to the reception point R'. Let L1 be the size of the first radio wave control board 1-1, L2 be the size of the second radio wave control board 1-2, and d be the distance between the transmitter 20 and the first radio wave control board 1-1. Ｔ１, the distance between the first radio wave control plate 1-1 and the second radio wave control plate 1-2 is d １２ , the distance between the second radio wave control board 1-2 and the receiving device 21 is d ２Ｒ In this case, it is preferable that the size L1 of first radio wave control board 1-1 and the size L2 of second radio wave control board 1-2 satisfy the relationships of the following formulas (3) and (4). Note that when first radio wave control board 1-1 and second radio wave control board 1-2 are rectangular, size L1 and size L2 are the shorter sides of first radio wave control board 1-1 and second radio wave control board 1-2, respectively.

[0046]

[0047]

[0048] By making the first radio wave control board 1-1 and the second radio wave control board 1-2 satisfy equations (3) and (4), respectively, the second radio wave control board 1-2 can receive effective power from the first radio wave control board 1-1, and the receiving device 21 can receive effective power from the second radio wave control board 1-2.

[0049] Third Embodiment A third embodiment will be described. Even if radio wave control plate 1 has an appropriate size, it may not be able to deliver effective power to receiving device 21 unless it has an appropriate refraction angle or reflection angle.

[0050] (Effective Range of Refraction Angle) The effective range of the refraction angle of the radio wave control plate according to the third embodiment will be described with reference to Fig. 9. Fig. 9 is a diagram for explaining the effective range of the refraction angle of the radio wave control band according to the third embodiment.

[0051] As shown in FIG. 9, the first radio wave control board 1-1 is disposed opposite the transmitting device 20. In this case, the vector pointing from the first radio wave control board 1-1 toward the center of the first radio wave control board 1-1 is defined as vector a. Vector a indicates the direction of travel of the radio waves transmitted by the transmitting device 20 to the first radio wave control board 1-1. The first radio wave control board 1-1 refracts the radio waves from the transmitting device 20, refracting them in the θ1 direction and emitting them toward the center of the second radio wave control board 1-2. The vector pointing from the center of the first radio wave control board 1-1 toward the center of the second radio wave control board 1-2 is defined as vector b. In this case, the relationship of equation (5) holds.

[0052]

[0053] Here, in reality, radio waves that have passed through radio wave control plate 1 have a certain beam pattern. FIG. 10 is a diagram for explaining the beam pattern of the radio wave control plate according to the third embodiment. In FIG. 10, the horizontal axis represents angle [deg (degrees)] and the vertical axis represents received power [dB (decibels)]. Beam pattern 110 shows the beam pattern of radio waves that have passed through radio wave control plate 1. In the example shown in FIG. 10, the angular range in which the power received in the θ direction is reduced by 3 [dB] is defined as the beam half-value angle φ. If θ deviates from equation (5) within ±φ, effective power within "maximum received power - 3 [dB]" can be obtained.

[0054] In the example shown in Figure 4, let vector a be the vector pointing from transmitting device 20 to the center of gravity of first radio wave control board 1-1. Let vector b be the vector pointing from the center of first radio wave control board 1-1 to the center of second radio wave control board 1-2. Let vector c be the vector pointing from the center of second radio wave control board 1-2 toward receiving device 21. Let φ1 be the beam half-maximum angle of refracted wave 32. Let φ2 be the beam half-maximum angle of refracted wave 33. If the refraction angle or reflection angle of first radio wave control board 1-1 is θ1, first radio wave control board 1-1 is configured to satisfy the following equation (6). If the refraction angle or reflection angle of second radio wave control board 1-2 is θ2, second radio wave control board 1-2 is configured to satisfy the following equation (7).

[0055]

[0056]

[0057] In the third embodiment, the first radio wave control board 1-1 and the second radio wave control board 1-2 are configured to satisfy equations (6) and (7), respectively, thereby enabling the receiving device 21 to properly receive effective power.

[0058] (Effect) Communication system 1000 according to the first aspect of the present disclosure includes first radio wave control board 1-1 and second radio wave control board 1-2, and first radio wave control board 1-1 refracts or reflects radio waves transmitted from transmitting device 20 in the direction of second radio wave control board 1-2, and second radio wave control board 1-2 refracts or reflects radio waves emitted from first radio wave control board 1-1 in the direction of receiving device 21 or in the direction of a third radio wave control board. As a result, the present disclosure can ensure line of sight of radio waves between transmitting device 20 and receiving device 21 by using multiple radio wave control boards.

[0059] A communication system 1000 according to a second aspect of the present disclosure is communication system 1000 according to the first aspect, in which first radio wave control board 1-1 and second radio wave control board 1-2 are capable of refracting or reflecting horizontally polarized waves and vertically polarized waves. As a result, in the present disclosure, first radio wave control board 1-1 and second radio wave control board 1-2 can appropriately refract or reflect radio waves, thereby appropriately ensuring line of sight of radio waves between transmitting device 20 and receiving device 21.

[0060] Communication system 1000 according to a third aspect of the present disclosure is communication system 1000 according to the first or second aspect, in which first radio wave control board 1-1 and second radio wave control board 1-2 include a plurality of unit structures 10 arranged two-dimensionally, and phase difference ΔΦ between adjacent unit structures 10 satisfies the following formula (1), where θ is the reflection angle or refraction angle when the angle of incidence of radio waves on first radio wave control board 1-1 and second radio wave control board 1-2 is 0°, d is the distance between adjacent unit structures, and k is the wave number of radio waves transmitted from transmitter 20. As a result, in the present disclosure, first radio wave control board 1-1 and second radio wave control board 1-2 can appropriately refract or reflect radio waves, and therefore line of sight of radio waves between transmitter 20 and receiver 21 can be appropriately ensured.

[0061]

[0062] A communication system 1000 according to a fourth aspect of the present disclosure is communication system 1000 according to the first or second aspect, in which the phase distribution of first radio wave control board 1-1 is set so that reflected or refracted radio waves are focused at the position of second radio wave control board 1-2. As a result, in the present disclosure, first radio wave control board 1-1 can appropriately refract or reflect radio waves, thereby appropriately ensuring line of sight of radio waves between transmitting device 20 and receiving device 21.

[0063] A communication system 1000 according to a fifth aspect of the present disclosure is the communication system 1000 according to any one of the first to fourth aspects, wherein the length L1 of the short side of the first radio wave control board 1-1 is set to λ where λ is the wavelength of the radio wave transmitted from the transmitting device 20 and d is the distance between the transmitting device 20 and the first radio wave control board 1-1. Ｔ１ , the distance between the first radio wave control plate 1-1 and the second radio wave control plate 1-2 is d １２ Then, the following formula (3) is satisfied, and the length L2 of the short side of second radio wave control board 1-2 is set to d ２Ｒ Then, the following formula (4) is satisfied. As a result, the present disclosure can appropriately set the sizes of first radio wave control board 1-1 and second radio wave control board 1-2 to deliver effective power to receiving device 21, thereby appropriately ensuring line-of-sight of radio waves between transmitting device 20 and receiving device 21.

[0064]

[0065]

[0066] A communication system 1000 according to a sixth aspect of the present disclosure is a communication system 1000 according to any one of the first to fifth aspects, wherein the refraction angle or reflection angle θ1 of first radio wave control board 1-1 satisfies the following equation (6) when the vector from transmitting device 20 toward the center of first radio wave control board 1-1 is vector a, the vector from the center of first radio wave control board 1-1 toward the center of second radio wave control board 1-2 is vector b, and the beam half-value angle of the radio waves emitted from first radio wave control board 1-1 is φ1, and the refraction angle or reflection angle θ2 of second radio wave control board 1-2 satisfies the following equation (7) when the vector from the center of second radio wave control board 1-2 toward receiving device 21 is vector c and the beam half-value angle of the radio waves emitted from second radio wave control board 1-2 is φ2. As a result, the present disclosure can appropriately set the refraction angle or reflection angle of the first radio wave control board 1-1 and the second radio wave control board 1-2 to deliver effective power to the receiving device 21, thereby appropriately ensuring line of sight of radio waves between the transmitting device 20 and the receiving device 21.

[0067]

[0068]

[0069] A communication system 1000 according to a seventh aspect of the present disclosure is the communication system 1000 according to any one of the first to sixth aspects, and uses a first radio wave control board 1-1 and a second radio wave control board 1-2 to bend radio waves transmitted by the transmitting device 20 by 90 degrees or more relative to the direction in which the radio waves were transmitted by the transmitting device 20. This allows the present disclosure to appropriately ensure line of sight of radio waves between the transmitting device 20 and the receiving device 21.

[0070] A communication system 1000 according to an eighth aspect of the present disclosure is the communication system 1000 according to any of the first to seventh aspects, and in an environment where line of sight of radio waves between the transmitting device 20 and the receiving device 21 is not ensured, the radio waves transmitted by the transmitting device 20 are refracted or reflected using the first radio wave control board 1-1 and the second radio wave control board 1-2 to ensure line of sight of radio waves between the transmitting device 20 and the receiving device 21. In this way, the present disclosure can appropriately ensure line of sight of radio waves between the transmitting device 20 and the receiving device 21 in an environment where line of sight of radio waves between the transmitting device 20 and the receiving device 21 is not ensured.

[0071] A method for installing a radio wave control board according to a ninth aspect of the present disclosure includes the steps of installing first radio wave control board 1-1 at a first installation position so as to refract or reflect radio waves transmitted from transmitting device 20 in the direction of second radio wave control board 1-2, and installing second radio wave control board 1-2 at a second installation position so as to refract or reflect radio waves emitted from first radio wave control board 1-1 in the direction of receiving device 21 or in the direction of a third radio wave control board. Thus, the present disclosure can ensure line-of-sight of radio waves between transmitting device 20 and receiving device 21 by installing multiple radio wave control boards 1 between transmitting device 20 and receiving device 21.

[0072] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the contents of these embodiments. Furthermore, the above-described components include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the above-described components can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the spirit of the above-described embodiments.

[0073] 1 Radio wave control plate 1-1 First radio wave control plate 1-2 Second radio wave control plate 10 Unit structure 20 Transmitting device 21 Receiving device 31 Radio wave 32, 33 Refracted wave 34 Reflected wave 41, 42, 43, 44, 45, 46, 47, 48 Obstacle 50 First Fresnel zone 52 Second Fresnel zone 54 Third Fresnel zone 56 Fourth Fresnel zone

Claims

1. A communication system comprising a first radio wave control plate and a second radio wave control plate, wherein the first radio wave control plate refracts or reflects radio waves transmitted from a transmitting device in the direction of the second radio wave control plate, and the second radio wave control plate refracts or reflects radio waves emitted from the first radio wave control plate in the direction of a receiving device or in the direction of a third radio wave control plate.

2. The communication system according to claim 1, wherein the first radio wave control plate and the second radio wave control plate are capable of refracting or reflecting horizontally polarized waves and vertically polarized waves.

3. The communication system described in claim 1 or 2, wherein the first radio wave control board and the second radio wave control board include a plurality of unit structures arranged two-dimensionally, and the phase difference ΔΦ between adjacent unit structures satisfies the following formula (1), where θ is the reflection angle or refraction angle when the angle of incidence of the radio waves on the first radio wave control board and the second radio wave control board is 0°, d is the distance between adjacent unit structures, and k is the wave number of the radio waves transmitted from the transmitting device.

4. A communication system as described in claim 1 or 2, wherein the phase distribution of the first radio wave control plate is set so that the reflected or refracted radio waves are focused at the position of the second radio wave control plate.

5. The length L1 of the short side of the first radio wave control plate is defined as λ, the wavelength of the radio wave transmitted from the transmitting device, and d, the distance between the transmitting device and the first radio wave control plate. Ｔ１ , the distance between the first radio wave control plate and the second radio wave control plate is d １２ Then, the following formula (3) is satisfied, and the length L2 of the short side of the second radio wave control plate is set to a value that is smaller than the distance between the second radio wave control plate and the receiving device by d ２Ｒ The communication system according to claim 1 or 2, wherein the following formula (4) is satisfied:

6. The communication system described in claim 1 or 2, wherein the refraction angle or reflection angle θ1 of the first radio wave control board satisfies the following formula (6) when the vector from the transmitting device toward the center of the first radio wave control board is vector a, the vector from the center of the first radio wave control board toward the center of the second radio wave control board is vector b, and the beam half-value angle of the radio wave emitted from the first radio wave control board is vector φ1, and the refraction angle or reflection angle θ2 of the second radio wave control board satisfies the following formula (7) when the vector from the center of the second radio wave control board toward the receiving device is vector c, and the beam half-value angle of the radio wave emitted from the second radio wave control board is φ2.

7. A communication system as described in claim 1 or 2, wherein the first radio wave control plate and the second radio wave control plate are used to bend the radio waves transmitted by the transmitting device by 90 degrees or more relative to the direction in which the transmitting device transmitted the radio waves.

8. A communication system as described in claim 1 or 2, in an environment where line of sight of the radio waves between the transmitting device and the receiving device is not ensured, the radio waves transmitted by the transmitting device are refracted or reflected using the first radio wave control plate and the second radio wave control plate, thereby ensuring line of sight of the radio waves between the transmitting device and the receiving device.

9. A method for installing a radio wave control plate, comprising: a step of installing a first radio wave control plate at a first installation position so as to refract or reflect radio waves transmitted from a transmitting device in the direction of a second radio wave control plate; and a step of installing the second radio wave control plate at a second installation position so as to refract or reflect radio waves emitted from the first radio wave control plate in the direction of a receiving device or in the direction of a third radio wave control plate.

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