Communication system, radio wave refraction plate, and method for calculating placement position of radio wave refraction plate

Abstract

This communication system comprises: a base station that is configured to transmit and receive radio waves; a terminal that is configured to transmit and receive the radio waves to and from the base station; and a plurality of radio wave refraction plates that are placed on the same plane between the base station and the terminal and that are configured to refract and emit the radio waves toward the terminal as refracted radio waves when the radio waves transmitted from the base station go through the refraction plates.

Description

Communication system, radio wave refraction plate, and method for calculating the installation position of the radio wave refraction plate

[0001] The present disclosure relates to a communication system, a radio wave refraction plate, and a method for calculating the installation position of the radio wave refraction plate.

[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 base station configured to transmit and receive radio waves, a terminal configured to transmit and receive the radio waves between the base station, and a plurality of radio wave refraction plates installed on the same plane between the base station and the terminal, configured to refract the radio waves transmitted from the base station toward the terminal when the radio waves pass through and emit the refracted radio waves.

[0005] The radio wave refraction plates of the present disclosure are installed in multiple locations on the same plane between a base station configured to transmit and receive radio waves and a terminal configured to transmit and receive the radio waves between the base station, and are configured to refract the radio waves transmitted from the base station toward the terminal when the radio waves pass through the terminal and emit them as refracted radio waves.

[0006] The method for calculating the installation positions of radio wave refraction plates of the present disclosure includes the steps of: calculating a geometric center of the central points of multiple installed radio wave refraction plates; setting a plane that passes through the geometric center and is perpendicular to a line connecting a transmitting point that transmits radio waves to the multiple radio wave refraction plates and a receiving point that receives the radio waves refracted by the radio wave refraction plates; projecting the multiple radio wave refraction plates onto the plane; and calculating installation positions of the multiple radio wave refraction plates so that the area of ​​the multiple radio wave refraction plates included in odd-order Fresnel zones on the plane is larger than the area of ​​the multiple radio wave refraction plates included in even-order Fresnel zones.

[0007] FIG. 1 is a diagram illustrating an example of the configuration of a communication system according to an embodiment. FIG. 2 is a diagram schematically illustrating an example of a radio wave refraction plate. FIG. 3 is a diagram illustrating a method for receiving radio waves according to a comparative example of this embodiment. FIG. 4 is a diagram illustrating a method for receiving radio waves according to a comparative example of this embodiment. FIG. 5 is a diagram illustrating a method for receiving radio waves according to this embodiment. FIG. 6 is a diagram illustrating a method for receiving radio waves according to this embodiment. FIG. 7 is a diagram illustrating a method for installing a radio wave refraction plate according to this embodiment. FIG. 8 is a diagram illustrating a Fresnel zone according to this embodiment. FIG. 9 is a flowchart showing the flow of a process for calculating the installation position of a radio wave refraction plate according to this embodiment. FIG. 10 is a diagram illustrating the angular dependency of received power according to a comparative example. FIG. 11 is a diagram illustrating the angular dependency of received power according to this embodiment. FIG. 12 is a diagram illustrating the transmission characteristics of radio wave refraction plates installed adjacent to each other according to this embodiment. FIG. 13 is a diagram illustrating the transmission characteristics of radio wave refraction plates installed adjacent to each other according to this embodiment.

[0008] 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.

[0009] 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. 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. 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.

[0010] [Embodiment] An example of the configuration of a communication system according to an embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing an example of the configuration of a communication system according to an embodiment.

[0011] 1, the communication system 1 includes a base station 10, a terminal 12, and a plurality of radio wave refraction plates 14. The communication system 1 may be, for example, a communication system compatible with millimeter wave communication capable of performing large-capacity data communication at high speed, such as a fifth-generation mobile communication system (hereinafter also referred to as "5G") or a sixth-generation mobile communication system (hereinafter also referred to as "6G").

[0012] The base station 10 is a wireless communication device configured to transmit and receive radio waves to and from various external devices. The base station 10 is configured to perform wireless communication with the terminal 12, for example, by transmitting and receiving radio waves compatible with 5G or 6G between the terminal 12 and the base station 10. In this embodiment, the base station 10 is configured to perform wireless communication with the terminal 12 via a plurality of radio wave refraction plates 14 installed on the same plane.

[0013] The terminal 12 is a wireless communication device configured to transmit and receive radio waves to and from various external devices. The terminal 12 is configured to perform wireless communication with the base station 10, for example, by transmitting and receiving radio waves compatible with 5G or 6G between the base station 10 and the terminal 12. In this embodiment, the terminal 12 is configured to perform wireless communication with the base station 10 via a plurality of radio wave refraction plates 14 installed on the same plane. An example of the terminal 12 is a smartphone used by a user, but the present disclosure is not limited thereto. The terminal 12 may also be, for example, a relay device that relays communication between the base station 10 and the smartphone used by the user.

[0014] The radio wave refraction plate 14 is a plate-shaped member configured to allow radio waves transmitted by the base station 10 to pass through. The radio wave refraction plate 14 is configured, for example, to receive radio waves transmitted by the base station 10, refract the radio waves at a predetermined angle, and emit them as refracted radio waves. Specifically, the radio wave refraction plate 14 is configured, when it receives radio waves transmitted by the base station 10, to refract the radio waves in the direction of the terminal 12, and emit them toward the terminal 12. The radio wave refraction plate 14 can be configured, for example, from a metamaterial that changes the phase of incident light.

[0015] Fig. 2 is a diagram schematically illustrating an example of the radio wave refraction plate 14. As shown in Fig. 2, the radio wave refraction plate 14 may include, for example, a substrate 20, an element 22, an element 24, an element 26, and an element 28.

[0016] The elements 22, 24, 26, and 28 may be formed on a substrate 20. The substrate 20 may have, for example, a rectangular shape, but is not limited to this. The elements 22, 24, 26, and 28 may be two-dimensionally arranged on the substrate 20. Specifically, in FIG. 2 , a plurality of elements 22 may be arranged in a row on the bottom level of the substrate 20. A plurality of elements 24 may be arranged in a row on the level above the level on which the elements 22 are arranged on the substrate 20. A plurality of elements 26 may be arranged in a row on the level above the level on which the elements 24 are arranged on the substrate 20. A plurality of elements 28 may be arranged in a row on the level above the level on which the elements 26 are arranged on the substrate 20. In other words, the radio wave refraction plate 14 may have a structure in which a plurality of elements of different sizes are periodically arranged. The elements 22 to 28 may each vary in the frequency band and the amount of phase change of the radio waves they change. Although elements 22 to 28 each have a rectangular shape, the shape is not limited to this. By changing the size and shape of elements 22, 24, 26, and 28, the frequency band and the amount of phase change of the radio waves to be refracted can be adjusted.

[0017] As shown in FIG. 1 , in this embodiment, the communication system 1 includes a plurality of radio wave refraction plates 14. The plurality of radio wave refraction plates 14 may be installed within the same plane 16. In the example shown in FIG. 1 , four radio wave refraction plates 14 are installed on the plane 16, but this is merely an example and does not limit the present disclosure. The plane 16 may be space or the surface of a transparent structure such as window glass. The plurality of radio wave refraction plates 14 refract radio waves W1 transmitted from the base station 10 and output the refracted radio waves W2 to the terminal 12.

[0018] [Comparative Example] Before describing the embodiment, a radio wave receiving method according to a comparative example of the present embodiment will be described. Figures 3 and 4 are diagrams for explaining a radio wave receiving method according to a comparative example of the present embodiment. The comparative example shows a method in which radio waves from a base station 10 are reflected and received by a terminal 12.

[0019] In the example shown in FIG. 3, two radio wave reflectors, radio wave reflector 30-1 and radio wave reflector 30-2, are shown. Radio wave reflector 30-1 and radio wave reflector 30-2 are configured to reflect radio waves W1 transmitted from base station 10 at a predetermined angle as reflected radio waves W3. In FIG. 3, the arrows attached to radio waves W1 and reflected radio waves W3 indicate the directions of travel of radio waves W1 and reflected radio waves W3, respectively. Radio wave reflector 30-1 and radio wave reflector 30-2 are installed at an interval along the Z-axis direction at origin O so that the phases of the reflected radio waves W3 reflected from each other are reinforced. In the example shown in FIG. 3, for example, at a position on straight line 41 in the ZX plane, the reflected radio waves W3 reflected by radio wave reflector 30-1 and the reflected radio waves W3 reflected by radio wave reflector 30-2 are in phase. That is, the received power of the radio wave W3 reflected by the radio wave reflector 30-1 and the received power of the radio wave W3 reflected by the radio wave reflector 30-2 are reinforced at a position on the straight line 41 in the ZX plane.

[0020] FIG. 4 shows an example in which, assuming that the wavelength of radio wave W1 is λ, the radio wave reflector 30-2 is shifted by λ / 4 from the origin O toward the positive side of the X-axis. For example, when λ is 28 GHz (gigahertz), λ / 4 is 2.7 mm (millimeters). In this case, as shown in FIG. 4, at a position on a straight line 41 in the ZX plane, the reflected radio wave W3 reflected by the radio wave reflector 30-1 and the reflected radio wave W3 reflected by the radio wave reflector 30-2 are out of phase. That is, at a position on the straight line 41 in the ZX plane, the reflected radio wave W3 reflected by the radio wave reflector 30-1 and the reflected radio wave W3 reflected by the radio wave reflector 30-2 weaken each other in received power. As such, even if the area of ​​the reflectors is increased using multiple radio wave reflectors, the reflected radio waves do not necessarily strengthen each other, and there are cases in which the received power is not improved.

[0021] Next, a radio wave receiving method according to this embodiment will be described. Figures 5 and 6 are diagrams for explaining the radio wave receiving method according to this embodiment.

[0022] The example shown in FIG. 5 shows two reflectors: a radio wave refraction plate 14-1 and a radio wave refraction plate 14-2. The radio wave refraction plate 14-1 and the radio wave refraction plate 14-2 are configured to reflect the radio wave W1 transmitted from the base station 10 as a refracted radio wave W2 at a predetermined angle θ. In FIG. 5, the arrows attached to the radio wave W1 and the refracted radio wave W2 indicate the traveling directions of the radio wave W1 and the refracted radio wave W2, respectively. The radio wave refraction plate 14-1 and the radio wave refraction plate 14-2 are installed at the origin O along the Z-axis direction, spaced apart, so as to reinforce the phases of the refracted radio waves W2 refracted by each other. In the example shown in FIG. 5, for example, at a position on a straight line 42 in the ZX plane, the refracted radio wave W2 refracted by the radio wave refraction plate 14-1 and the refracted radio wave W2 refracted by the radio wave refraction plate 14-2 are in phase. That is, the received power of the refracted radio wave W2 refracted by the radio wave refraction plate 14-1 and the received power of the refracted radio wave W2 refracted by the radio wave refraction plate 14-2 are reinforced at a position on the straight line 32 in the ZX plane.

[0023] 6 shows an example in which the radio wave refraction plate 14-2 is shifted by λ / 4 from the origin O in the positive direction of the X-axis, where λ is the wavelength of the radio wave W1. In this embodiment, as shown in FIG. 6, even if the radio wave refraction plate 14-2 is shifted in the positive direction of the X-axis, the path length remains almost unchanged. Therefore, in this embodiment, even if the radio wave refraction plate 14-2 is shifted in the positive direction of the X-axis, the refracted radio wave W2 refracted by the radio wave refraction plate 14-1 and the refracted radio wave W2 refracted by the radio wave refraction plate 14-2 are in phase at a position on the straight line 32 in the ZX plane. In other words, in this embodiment, the received power is not weakened, and the received power can be improved by increasing the area of ​​the reflectors using multiple radio wave reflectors.

[0024] In this embodiment, when the distance between the radio wave refraction plate 14-1 and the radio wave refraction plate 14-2 is s and the refraction angle of the refracted radio wave W2 is θ, it is preferable that the deviation in the thickness direction (X-axis direction in FIG. 6) between the radio wave refraction plate 14-1 and the radio wave refraction plate 14-2 is s / tan θ or less. By making the deviation in the thickness direction (X-axis direction in FIG. 5) between the radio wave refraction plate 14-1 and the radio wave refraction plate 14-2 s / tan θ or less, the received power can be improved.

[0025] [Method of Installing the Radio Wave Refraction Plate] Next, a method of installing the radio wave refraction plate according to this embodiment will be described. Fig. 7 is a diagram for explaining the method of installing the radio wave refraction plate according to this embodiment.

[0026] In this embodiment, when considering the path of radio waves from a transmission point T through points on the radio wave refraction plate 14 to a reception point R, the radio wave refraction plate 14 is installed so that the area installed in the region where the radio waves constructively interact is larger than the area installed in the region where the radio waves destructively interact. This makes it possible to obtain higher received power in this embodiment. In this embodiment, the region where the radio waves constructively interact is called an odd-order Fresnel zone, and the region where the radio waves destructively interact is called an even-order Fresnel zone.

[0027] (Fresnel Zone) The definition of the Fresnel zone according to this embodiment will be explained. As shown in Fig. 7, consider a situation in which radio waves from a transmission point T pass through a plurality of radio wave refraction plates 14 and reach a reception point R. The transmission point T indicates the position of the antenna of the base station 10, and the reception point R indicates the position of the antenna of the terminal 12. In Fig. 7, the geometric center (center of gravity) of the central points of the plurality of radio wave refraction plates 14 is defined as the geometric center C. The linear distance between the transmission point T and the geometric center C is defined as d １ The distance between the receiving point R and the geometric center C is d ２ Consider a plane P that passes through the geometric center C and is perpendicular to a line TR that connects the transmitting point T and the receiving point R. Now, consider a circle on the plane P that has the geometric center C as its center and whose radius is defined by the following equation (1).

[0028]

[0029] In equation (1), n ​​is a natural number, and λ is the wavelength of the radio wave.

[0030] 8 is a diagram for explaining the Fresnel zone according to this embodiment. In this embodiment, in formula (1), the radius R ｎ－１ From radius R ｎ The annular portion in the range of is defined as the n-th Fresnel zone. In the example shown in Fig. 8, a first Fresnel zone 50, a second Fresnel zone 52, a third Fresnel zone 54, and a fourth Fresnel zone 56 are shown.

[0031] A method for calculating the installation position of the radio wave refraction plate according to this embodiment will be described with reference to Fig. 8 and Fig. 9. Fig. 9 is a flowchart showing the flow of processing for calculating the installation position of the radio wave refraction plate according to this embodiment.

[0032] The process shown in FIG. 9 is executed by, for example, an information processing device such as a personal computer (not shown).

[0033] The information processing device calculates the geometric center C of the central points of the installed radio wave refraction plates 14 (step S10), and then proceeds to step S12.

[0034] The information processing device sets a plane P that passes through the geometric center C and is perpendicular to the line TR that connects the transmission point T and the reception point R (step S12), and then proceeds to step S14.

[0035] The information processing device projects the plurality of radio wave refraction plates 14 onto the plane P (step S14), and then proceeds to step S16.

[0036] The information processing device calculates the installation positions of the multiple radio wave refraction plates 14 (step S16). Specifically, the information processing device calculates the installation positions of the multiple radio wave refraction plates 14 so that the area of ​​the radio wave refraction plates 14 included in the odd-order Fresnel zones is larger than the area of ​​the radio wave refraction plates 14 included in the even-order Fresnel zones. More specifically, in the example shown in Figure 7, the information processing device calculates the installation positions of the multiple radio wave refraction plates 14 so that the area of ​​the radio wave refraction plates 14 included in the first Fresnel zone 50 and the third Fresnel zone 54 is larger than the area of ​​the radio wave refraction plates 14 included in the second Fresnel zone 52 and the fourth Fresnel zone 56. Then, the process proceeds to step S18.

[0037] The information processing device outputs installation position information regarding the installation positions of the plurality of radio wave refraction plates 14 (step S18), which allows the user to adjust the installation positions of the plurality of radio wave refraction plates 14 based on the installation position information.

[0038] (Distance Setting Method) Next, a method for setting the distance between the terminal 12 according to this embodiment and the plurality of radio wave refraction plates 14 will be described.

[0039] In the vicinity area where the distance from the radio wave refraction plate 14 is sufficiently shorter than the long side of the radio wave refraction plate 14, the beam width of the refracted radio wave from the radio wave refraction plate 14 is wide and the power is dispersed, making it difficult to obtain high reception power. The linear distance between the geometric center C of the centers of the multiple radio wave refraction plates 14 and the reception point R is defined as d ２ , the sum of the maximum dimensions (for example, diagonals) of the installed radio wave refraction plates 14 is L ｓｕｍ Then, d ２ It is preferable that the following formula (2) is satisfied.

[0040]

[0041] straight line distance d ２ When equation (2) is satisfied, the beam width of the refracted radio wave becomes narrower, and higher received power can be obtained compared to the case where only one radio wave refraction plate 14 is installed.

[0042] (Angle Dependence of Received Power) The angle dependence of received power will be described with reference to Fig. 10 and Fig. 11. Fig. 10 is a diagram for explaining the angle dependence of received power according to a comparative example. Fig. 11 is a diagram for explaining the angle dependence of received power according to the embodiment.

[0043] FIG. 10 shows the angular dependence of the received power when the above formula (2) is not satisfied. Specifically, FIG. 10 shows the angular dependence of the received power when the above formula (2) is not satisfied. ２ is 0.75m, L ｓｕｍ 1 shows the angular dependency of the received power when λ is 0.6 m and λ is 28 GHz.

[0044] Fig. 10 shows waveforms 101 and 102. In Fig. 10, the horizontal axis represents the refraction angle [deg (degrees)] and the vertical axis represents the gain [dB]. Waveform 101 shows the angular dependency of the received power when one radio wave refraction plate 14 is installed. Waveform 102 shows the angular dependency of the received power when two radio wave refraction plates 14 are installed. As shown by waveforms 101 and 102, the power distribution of the refracted radio waves becomes wider by installing two radio wave refraction plates 14.

[0045] FIG. 11 shows the angular dependence of the received power when the above formula (2) is satisfied. Specifically, FIG. ２ is 5.0 m, L ｓｕｍ 1 shows the angular dependency of the received power when λ is 0.6 m and λ is 28 GHz.

[0046] Fig. 11 shows waveforms 103 and 104. In Fig. 11, the horizontal axis represents the refraction angle [deg] and the vertical axis represents the gain [dB]. Waveform 103 shows the angular dependency of the received power when one radio wave refraction plate 14 is installed. Waveform 104 shows the angular dependency of the received power when two radio wave refraction plates 14 are installed. As shown by waveforms 103 and 104, installing two radio wave refraction plates 14 improves the gain of the received power and narrows the power distribution.

[0047] That is, as shown in FIGS. 10 and 11, d ２ When the condition of equation (2) above is satisfied, higher reception power can be obtained by installing a plurality of radio wave refraction plates 14.

[0048] (Relative Relationship) Next, a preferred installation method for installing a plurality of radio wave refraction plates 14 adjacent to another radio wave refraction plate 14 will be described.

[0049] 12 and 13 are diagrams for explaining the transmission characteristics of adjacently installed radio wave refraction plates according to the embodiment.

[0050] 12, the radio wave refraction plate 14-1 and the radio wave refraction plate 14-2 are installed adjacent to each other so that the area included in the odd-order Fresnel zone is larger than the area included in the even-order Fresnel zone. The radio wave refraction plate 14-1 and the radio wave refraction plate 14-2 may be installed in the same odd-order Fresnel zone or in different odd-order Fresnel zones.

[0051] The radio wave refraction plate 14-1 includes an element 22A, an element 24A, an element 26A, etc. The radio wave refraction plate 14-2 includes an element 22B, an element 24B, etc. In the example shown in Fig. 12, the elements 22A, 24A, 26A, etc., and the elements 22B, 24B, etc. are installed adjacent to each other.

[0052] In the graph of Figure 12, the horizontal axis indicates the installation position of the radio wave refraction plate 14, and the vertical axis indicates the amount of phase change [degrees]. Point P1 indicates the installation position and amount of phase change of element 22A. Point P2 indicates the installation position and amount of phase change of element 24A. Point P3 indicates the installation position and amount of phase change of element 26A. Point P4 indicates the installation position and amount of phase change of element 22B. Point P5 indicates the installation position and amount of phase change of element 24B.

[0053] 12, in this embodiment, the radio wave refraction plate 14-1 and the radio wave refraction plate 14-2 are installed so that points P1 to P5 are on a straight line 61. This allows the radio wave refraction plate 14-1 and the radio wave refraction plate 14-2 to increase the received power of refracted radio waves, thereby further improving the characteristics.

[0054] 13, the radio wave refraction plate 14-1 is installed so that the area included in the odd-order Fresnel zone is larger than the area included in the even-order Fresnel zone. The radio wave refraction plate 14-3 is installed so that the area included in the even-order Fresnel zone is larger than the area included in the odd-order Fresnel zone. The radio wave refraction plate 14-1 and the radio wave refraction plate 14-3 are installed adjacent to each other.

[0055] In the graph of Figure 13, the horizontal axis indicates the installation position of the radio wave refraction plate 14, and the vertical axis indicates the amount of phase change [degrees]. Point P1 indicates the installation position and amount of phase change of element 22A. Point P2 indicates the installation position and amount of phase change of element 24A. Point P3 indicates the installation position and amount of phase change of element 26A. Point P11 indicates the installation position and amount of phase change of element 22C. Point P12 indicates the installation position and amount of phase change of element 24C.

[0056] 13, in this embodiment, the radio wave refraction plate 14-1 is installed so that points P1 to P3 are on a straight line 61, and the radio wave refraction plate 14-3 is installed so that points P11 and P12 are off the straight line 61. In other words, a radio wave refraction plate whose area included in the even-order Fresnel zone is larger than the area included in the odd-order Fresnel zone is installed so as to be off the straight line 61.

[0057] 13, the radio wave refraction plate 14-3 is installed so that points P11 and P12 are on a straight line 62. In other words, the radio wave refraction plate 14-3 is installed so that the amount of phase change is deviated from that of the radio wave refraction plate 14-1. Since the even-order Fresnel zone is an area where radio waves weaken each other, by installing the radio wave refraction plate 14-3 so that it is off the straight line 61, it is possible to increase the received power of the refracted radio waves and further improve the characteristics.

[0058] The arrow between the straight lines 61 and 62 indicates the difference in the amount of phase change between the straight lines 61 and 62. The characteristics can be further improved by setting the difference in the amount of phase change between the straight lines 61 and 62 to, for example, 180°. Note that the difference in the amount of phase change between the straight lines 61 and 62 is not limited to 180°.

[0059] 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.

[0060] REFERENCE SIGNS LIST 1 communication system 10 base station 12 terminal 14 radio wave refraction plate 16 plane 20 substrate 22, 24, 26, 28 elements 30-1, 30-2 radio wave reflection plate 50 first Fresnel zone 52 second Fresnel zone 54 third Fresnel zone 56 fourth Fresnel zone

Claims

1. A base station configured to transmit and receive radio waves; a terminal configured to transmit and receive the radio waves between the base station and the terminal; a radio wave refraction plate that is installed on the same plane between the base station and the terminal, and that is configured to refract the radio wave transmitted from the base station toward the terminal when the radio wave passes through the radio wave refraction plate, and to emit the refracted radio wave; 23. A communication system comprising:

2. Each of the plurality of radio wave refraction plates is installed in an area defined on an installation plane that passes through the geometric centers of the plurality of radio wave refraction plates and is perpendicular to a line connecting the antenna of the base station and the antenna of the terminal, based on a first straight-line distance between the antenna of the base station and the geometric center of each of the plurality of radio wave refraction plates, and a second straight-line distance between the antenna of the terminal and the geometric center of each of the plurality of radio wave refraction plates. The communication system according to claim 1 .

3. The first linear distance is d １ , the second straight-line distance is d ２ Then, on the plane, consider a circle having a geometric center C as its center and a radius defined by the following formula (1): [0010] In the above formula (1), n ​​is a natural number, λ is the wavelength of the radio wave, The radio wave refraction plate has a radius R ｎ－１ From radius R ｎ When the annular portion in the range of is defined as an n-th Fresnel zone, the areas of the plurality of radio wave refracting plates included in the odd-order Fresnel zone are set to be larger than the areas of the plurality of radio wave refracting plates included in the even-order Fresnel zone. The communication system according to claim 2.

4. a region defined based on the first linear distance and the second linear distance includes an odd-order Fresnel zone and an even-order Fresnel zone, each of the plurality of radio wave refraction plates is installed such that, when an area of ​​each of the plurality of radio wave refraction plates projected onto the installation plane is considered, an area included in the odd-order Fresnel zone is larger than an area included in the even-order Fresnel zone; The communication system according to claim 2.

5. The plurality of radio wave refraction plates have a thickness direction deviation between adjacent radio wave refraction plates of s / tan θ or less, where s is a distance between the adjacent radio wave refraction plates and θ is a refraction angle of the radio wave.

3. A communication system according to claim 1 or 2.

6. The sum of the maximum dimensions of the plurality of radio wave refracting plates is L ｓｕｍ When the wavelength of the radio wave is λ, the distance between the antenna of the terminal and the geometric center of each of the plurality of radio wave refracting plates is 0.62 × (L ｓｕｍ ３ / λ) is greater than 3. A communication system according to claim 1 or 2.

7. the plurality of radio wave refraction plates are arranged so that when the coordinates of each of the plurality of unit structures included in the plurality of radio wave refraction plates are plotted on a graph in which the horizontal axis indicates position and the vertical axis indicates transmission phase, the coordinates are on a straight line.

3. A communication system according to claim 1 or 2.

8. When the coordinates of each of the plurality of unit structures included in the plurality of radio wave refraction plates are plotted on a graph in which the horizontal axis indicates position and the vertical axis indicates transmission phase, among the plurality of radio wave refraction plates, those in which the area included in the odd-order Fresnel zone is larger than the area included in the even-order Fresnel zone are placed on a straight line, and those in which the area included in the even-order Fresnel zone is larger than the area included in the odd-order Fresnel zone are placed off the straight line.

5. The communication system according to claim 4.

9. For an area included in the even-order Fresnel zone that is larger than an area included in the odd-order Fresnel zone, the area is set so that the phase change amount is shifted by 180° from the straight line.

9. The communication system according to claim 8.

10. A radio wave refraction plate is installed on the same plane between a base station configured to transmit and receive radio waves and a terminal configured to transmit and receive the radio waves between the base station, and is configured to refract the radio waves transmitted from the base station toward the terminal when the radio waves pass through the base station, and to emit the refracted radio waves.

11. The radio wave refraction plates are installed in an area defined based on a first straight-line distance between the antenna of the base station and each of the geometric centers of the radio wave refraction plates and a second straight-line distance between the antenna of the terminal and each of the geometric centers of the radio wave refraction plates on an installation plane that passes through the geometric centers of the radio wave refraction plates and is perpendicular to a straight line connecting the antenna of the base station and the antenna of the terminal.

11. A radio wave refracting plate according to claim 10.

12. The first linear distance is d １ , the second straight-line distance is d ２ Then, on the plane, consider a circle having a geometric center C as its center and a radius defined by the following formula (1): [0025] In the above formula (1), n ​​is a natural number, λ is the wavelength of the radio wave, Radius R ｎ－１ From radius R ｎ When the annular portion in the range of is defined as an n-th Fresnel zone, the areas of the plurality of radio wave refracting plates included in the odd-order Fresnel zone are set to be larger than the areas of the plurality of radio wave refracting plates included in the even-order Fresnel zone.

12. A radio wave refracting plate according to claim 11.

13. a region defined based on the first linear distance and the second linear distance includes an odd-order Fresnel zone and an even-order Fresnel zone, When the area of ​​each of the plurality of radio wave refraction plates projected onto the installation plane is considered, the area included in the odd-order Fresnel zone is set to be larger than the area included in the even-order Fresnel zone.

12. A radio wave refracting plate according to claim 11.

14. The plurality of radio wave refraction plates have a thickness direction deviation between adjacent radio wave refraction plates of s / tan θ or less, where s is a distance between the adjacent radio wave refraction plates and θ is a refraction angle of the radio wave.

12. A radio wave refraction plate according to claim 10 or 11.

15. The sum of the maximum dimensions of the plurality of radio wave refracting plates is L ｓｕｍ When the wavelength of the radio wave is λ, the distance between the antenna of the terminal and the geometric center of each of the plurality of radio wave refracting plates is 0.62 × (L ｓｕｍ ３ / λ) is greater than 12. A radio wave refraction plate according to claim 10 or 11.

16. The unit structures are arranged so that when the coordinates of each of the unit structures included in the plurality of radio wave refraction plates are plotted on a graph in which the horizontal axis indicates position and the vertical axis indicates transmission phase, the coordinates are arranged so as to form a straight line.

12. A radio wave refraction plate according to claim 10 or 11.

17. when the coordinates of each of the plurality of unit structures included in the plurality of radio wave refraction plates are plotted on a graph in which the horizontal axis indicates position and the vertical axis indicates transmission phase, among the plurality of radio wave refraction plates, those in which the area included in the odd-order Fresnel zone is larger than the area included in the even-order Fresnel zone are placed on a straight line, and those in which the area included in the even-order Fresnel zone is larger than the area included in the odd-order Fresnel zone are placed off the straight line.

14. A radio wave refracting plate according to claim 13.

18. For an area included in the even-order Fresnel zone that is larger than an area included in the odd-order Fresnel zone, the area is set so that the phase change amount is shifted by 180° from the straight line.

18. A radio wave refracting plate according to claim 17.

19. Calculating a geometric center of the center points of the multiple radio wave refracting plates that are installed; setting a plane that passes through the geometric center and is perpendicular to a straight line that connects a transmission point that transmits radio waves to the plurality of radio wave refraction plates and a reception point that receives the radio waves refracted by the radio wave refraction plate; projecting the plurality of radio wave refracting plates onto the plane; calculating installation positions of the plurality of radio wave refracting plates so that the areas of the plurality of radio wave refracting plates included in odd-order Fresnel zones on the plane are larger than the areas of the plurality of radio wave refracting plates included in even-order Fresnel zones; A method for calculating the installation position of a radio wave refraction plate, comprising:

Images