Radio wave control plate and communication system

Abstract

This radio wave control plate is disposed between a transmitter for transmitting radio waves and a receiver for receiving the radio waves. In the radio wave control plate, at least one of the length in a first direction parallel to a refractive surface or a reflective surface of the radio waves and the length in a second direction perpendicular to the first direction is 75-125% of twice the radius of a circular region defined by the positional relationship among the transmitter, the radio wave control plate, and the receiver.

Description

Radio wave control board and communication system

[0001] The present disclosure relates to a radio wave control board and a communication system.

[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 radio wave control board of the present disclosure is a radio wave control board installed between a transmitter that transmits radio waves and a receiver that receives the radio waves, and at least one of the length in a first direction parallel to the refraction or reflection surface of the radio waves and the length in a second direction perpendicular to the first direction of the radio wave control board is 75% or more and 125% or less of twice the radius of a circular area defined by the positional relationship between the transmitter, the radio wave control board, and the receiver.

[0005] The communication system of the present disclosure includes a transmitter that transmits radio waves, a plurality of radio wave control plates that refract or reflect the radio waves transmitted from the transmitter, and a receiver that receives the radio waves refracted or reflected by the plurality of radio wave control plates, wherein at least one of the length in a first direction parallel to the refraction or reflection surface of the radio waves and the length in a second direction perpendicular to the first direction of the radio wave control plate is between 75% and 125% of twice the radius of a circular area defined by the positional relationship between the transmitter, the radio wave control plate, and the receiver.

[0006] 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 an installation state of a radio wave refraction plate according to the first embodiment. FIG. 4 is a diagram illustrating an installation method of a radio wave refraction plate according to the first embodiment. FIG. 5 is a diagram illustrating the relationship between a radio wave refraction plate and a Fresnel zone according to the first embodiment. FIG. 6 is a diagram illustrating the angular dependence of received power according to the first embodiment. FIG. 7 is a diagram illustrating the relationship between a radio wave refraction plate and a Fresnel zone according to the second embodiment. FIG. 8 is a diagram illustrating the angular dependence of received power according to the second embodiment. FIG. 9 is a diagram illustrating the relationship between a radio wave refraction plate and a Fresnel zone according to the third embodiment. FIG. 10 is a diagram illustrating the angular dependence of received power according to the third embodiment. FIG. 11 is a diagram illustrating an installation method of multiple radio wave refraction plates according to the fourth embodiment. FIG. 12 is a schematic diagram illustrating multiple radio wave refraction plates according to the fourth embodiment. FIG. 13 is a diagram illustrating the angular dependence of received power according to the fourth embodiment. FIG. 14 is a diagram illustrating the relationship between gaps between multiple radio wave refraction plates according to the fifth embodiment and received power.

[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] [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.

[0009] 1, the communication system 1 includes a base station 10, a terminal 12, and a radio wave refraction plate 14. The communication system 1 may be a communication system 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").

[0010] 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.

[0011] 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.

[0012] 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 an incident wave.

[0013] 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.

[0014] 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.

[0015] In this embodiment, the communication system 1 is described as including a radio wave refraction plate 14 that refracts radio waves, but the present disclosure is not limited to this. The communication system 1 may include a radio wave reflection plate, instead of the radio wave refraction plate 14, that receives radio waves transmitted from the base station 10, reflects the radio waves at a predetermined angle, and emits the reflected radio waves. The radio wave refraction plate and the radio wave reflection plate are types of radio wave control plates.

[0016] [First Embodiment] (Installation Method of Radio Wave Refraction Plate) Next, a method of installing a radio wave refraction plate according to the first embodiment will be described. FIG. 3 is a diagram illustrating the installation of the radio wave refraction plate according to the first embodiment. FIG. 3 is a schematic diagram showing the installation of the radio wave refraction plate 14 as viewed from above. As shown in FIG. 3, the radio wave refraction plate 14 is installed in a position that overlooks the base station 10 and the terminal 12, near an obstacle 11 that may interfere with radio waves between the base station 10 and the terminal 12. In the first embodiment, the radio wave refraction plate 14 is installed in an area defined based on the positional relationship between the base station 10, the terminal 12, and the radio wave refraction plate 14. Specifically, the radio wave refraction plate 14 is installed in a Fresnel zone that is defined based on the straight-line distance between the base station 10 and the radio wave refraction plate 14 and the straight-line distance between the terminal 12 and the radio wave refraction plate 14. 3, terminal 12' represents a virtual terminal 12 located on an extension of the straight line connecting base station 10 and radio wave refraction plate 14. The straight-line distance between terminal 12 and radio wave refraction plate 14 is the same as the direct distance between terminal 12' and radio wave refraction plate 14. In the example shown in FIG. 3, when terminal 12 is located on the arc between terminal 12 and terminal 12', the straight-line distance between terminal 12 and radio wave refraction plate 14 does not change.

[0017] (Fresnel Zone) The definition of the Fresnel zone according to the first embodiment will be described. FIG. 4 is a diagram illustrating a method for installing a radio wave refraction plate according to the first embodiment. Transmission point T indicates the position of the antenna of the base station 10 shown in FIG. 3. Reception point R indicates the position of the antenna of the terminal 12 shown in FIG. 3. Reception point R' indicates the position of the antenna of the virtual terminal 12 shown in FIG. 3. Center point O indicates the center point of the radio wave refraction plate 14. That is, in the example shown in FIG. 4, the straight-line distance between center point O and reception point R is the same as the straight-line distance between center point O and reception point R'. In the first embodiment, when considering the path of a radio wave from transmission point T through points on the radio wave refraction plate 14 to reach reception point R, the radio wave refraction plate 14 is installed in a region where radio waves constructively interact with each other. This enables this embodiment to obtain higher received power. In this embodiment, a region where radio waves constructively interact with each other is called an odd-order Fresnel zone, and a region where radio waves destructively interact with each other is called an even-order Fresnel zone.

[0018] As shown in Fig. 4, consider a situation in which a radio wave from a transmitting point T passes through a radio wave refraction plate 14 and reaches a receiving point R. In Fig. 4, the center point of the radio wave refraction plate 14 is set to a center point O. The linear distance between the transmitting point T and the center point O is d ＴＸ The linear distance between the receiving point R and the center point O is d ＲＸ Consider a plane P that is perpendicular to the line connecting the transmitting point T and the receiving point R', passing through the center point O. Now, consider a circle on the plane P that is centered at the center point O and whose radius is defined by the following equation (1).

[0019]

[0020] In equation (1), n ​​is a natural number, and λ is the wavelength of the radio wave.

[0021] In this embodiment, in the 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 Figure 3, a first Fresnel zone 30, a second Fresnel zone 32, a third Fresnel zone 34, and a fourth Fresnel zone 36 are shown.

[0022] (Radio wave refraction plate and Fresnel zone) The relationship between the radio wave refraction plate and the Fresnel zone according to the first embodiment will be described with reference to Fig. 5. Fig. 5 is a diagram for explaining the relationship between the radio wave refraction plate and the Fresnel zone according to the first embodiment.

[0023] As shown in FIG. 5 , in the first embodiment, the length a of the upper side 14 a and the lower side 14 b, which are sides (horizontal sides) parallel to the refraction surface (plane P) of the radio wave refraction plate 14, is formed within a range of twice the radius of the first Fresnel zone 30 ±25%. In other words, the lengths of the upper side 14 a and the lower side 14 b are preferably formed within a range of 75% to 125% of twice the radius of the first Fresnel zone 30. When the radio wave refraction plate 14 is formed within this range, the received power can be improved. In the example shown in FIG. 5 , the lengths of the left side 14 c and the right side 14 d may be arbitrary.

[0024] Fig. 6 is a diagram showing the angular dependency of the received power according to the first embodiment, which shows the angular dependency of the received power depending on the size (height length x horizontal length) of the radio wave refraction plate 14.

[0025] 6, the linear distance between the radio wave transmission point and the radio wave refraction plate 14 is 50 m, the linear distance between the radio wave reception point and the radio wave refraction plate 14 is 2 m, and the radio wave frequency is 28 GHz (gigahertz). In this case, the radius of the first Fresnel zone 30 is 0.14 m. The received power is normalized by the received power when the radio wave refraction plate 14 is not installed.

[0026] 6 shows waveforms 101, 102, 103, 104, and 105. Waveform 101 shows the angular dependence of received power for a 1.15 m x 1.2 m radio wave refraction plate 14. Waveform 102 shows the angular dependence of received power for a 0.33 m x 0.36 m radio wave refraction plate 14. Waveform 103 shows the angular dependence of received power for a 0.27 m x 0.3 m radio wave refraction plate 14. Waveform 104 shows the angular dependence of received power for a 0.19 m x 0.22 m radio wave refraction plate 14. Waveform 105 shows the angular dependence of received power for a 0.13 m x 0.16 m radio wave refraction plate 14.

[0027] Waveform 102 shows the angular dependence of the received power of a radio wave refraction plate 14 whose horizontal length is approximately twice the radius of the first Fresnel zone 30 plus 25%. Waveform 103 shows the angular dependence of the received power of a radio wave refraction plate 14 whose horizontal length is approximately twice the radius of the first Fresnel zone 30 plus 25%. Waveform 104 shows the angular dependence of the received power of a radio wave refraction plate 14 whose horizontal length is approximately twice the radius of the first Fresnel zone 30 minus 25%. Waveforms 102, 103, and 104 all exhibit good characteristics, with a peak normalized received power of 3 dB or more at a refraction angle of 45°. That is, in the first embodiment, the received power can be improved by setting the horizontal length of the radio wave refraction plate 14 within the range of approximately twice the radius of the first Fresnel zone 30 plus or minus 25%.

[0028] [Second embodiment] (Radio wave refraction plate and Fresnel zone) The relationship between the radio wave refraction plate and the Fresnel zone according to the second embodiment will be described with reference to Fig. 7. Fig. 7 is a diagram for explaining the relationship between the radio wave refraction plate and the Fresnel zone according to the second embodiment.

[0029] As shown in FIG. 7 , in the second embodiment, when it is desired to improve the reception power only in a certain height area, the lengths of the left side 14Ac and the right side 14Ad, which are the sides in the height direction of the radio wave refraction plate 14A, are formed within the range of ±25% of twice the radius of the first Fresnel zone 30.

[0030] Fig. 8 is a diagram showing the angular dependency of the received power according to the second embodiment, which shows the angular dependency of the received power depending on the size (height length x horizontal length) of the radio wave refraction plate 14A.

[0031] 8, the linear distance between the radio wave transmission point and the radio wave refraction plate 14A is 50 m, the linear distance between the radio wave reception point and the radio wave refraction plate 14A is 2 m, and the radio wave frequency is 28 GHz. In this case, the radius of the first Fresnel zone 30 is 0.14 m. The received power is normalized by the received power when the radio wave refraction plate 14A is not installed.

[0032] 8 shows waveforms 111, 112, and 113. Waveform 111 shows the angular dependence of the received power of a 0.3 m x 0.3 m radio wave refraction plate 14A. Waveform 112 shows the angular dependence of the received power of a 0.6 m x 0.3 m radio wave refraction plate 14A. Waveform 113 shows the angular dependence of the received power of a 0.05 m x 0.3 m radio wave refraction plate 14A.

[0033] Waveform 111 shows the angular dependence of the received power of a radio wave refraction plate 14A whose height length is approximately 4.2 times the radius of the first Fresnel zone 30. Waveform 112 shows the angular dependence of the received power of a radio wave refraction plate 14A whose horizontal length is approximately twice the radius of the first Fresnel zone 30. Waveforms 111 and 112 exhibit peak normalized received power of 3 dB or more at a refraction angle of 45°, indicating favorable characteristics. Comparing waveforms 111 and 112, waveform 111 exhibits better characteristics. That is, in the second embodiment, the received power can be improved by setting the height length of the radio wave refraction plate 14A within a range of ±25% of approximately twice the radius of the first Fresnel zone 30.

[0034] [Third embodiment] (Radio wave refraction plate and Fresnel zone) The relationship between the radio wave refraction plate and the Fresnel zone according to the third embodiment will be described with reference to Fig. 9. Fig. 9 is a diagram for explaining the relationship between the radio wave refraction plate and the Fresnel zone according to the third embodiment.

[0035] As shown in FIG. 9, in the third embodiment, the lengths of the left side 14Bc and the right side 14Bd, which are the sides in the height direction of the radio wave refraction plate 14B, are twice the radius of the first Fresnel zone 30, and the lengths of the top side 14Ba and the bottom side 14Bb, which are the sides in the horizontal direction, are longer than the lengths of the left side 14Bc and the right side 14Bd.

[0036] Fig. 10 is a diagram showing the angular dependency of the received power according to the third embodiment, which illustrates the angular dependency of the received power depending on the size (height length x horizontal length) of the radio wave refraction plate 14B.

[0037] 10, the linear distance between the radio wave transmission point and the radio wave refraction plate 14B is 50 m, the linear distance between the radio wave reception point and the radio wave refraction plate 14B is 2 m, and the radio wave frequency is 28 GHz. In this case, the radius of the first Fresnel zone 30 is 0.14 m. The received power is normalized by the received power when the radio wave refraction plate 14B is not installed.

[0038] 10 shows waveforms 121, 122, 123, and 124. Waveform 121 shows the angular dependence of the received power of the 0.6 m x 0.6 m radio wave refraction plate 14B. Waveform 122 shows the angular dependence of the received power of the 0.3 m x 0.6 m radio wave refraction plate 14B. Waveform 123 shows the angular dependence of the received power of the 0.3 m x 0.3 m radio wave refraction plate 14B. Waveform 124 shows the angular dependence of the received power of the 0.3 m x 0.05 m radio wave refraction plate 14B.

[0039] 10, waveform 123 shows the best characteristics of normalized received power at a refraction angle of 45 degrees. However, waveform 122 shows a normalized received power of 3 dB over the widest range. That is, in the third embodiment, by making the height direction length of radio wave refraction plate 14B twice the radius of first Fresnel zone 30 and making the horizontal direction length equal to or greater than the height direction length, high received power can be obtained over a wide range.

[0040] [Fourth embodiment] Next, a fourth embodiment will be described. In the fourth embodiment, a plurality of radio wave refraction plates are arranged to improve the received power.

[0041] In the fourth embodiment, the received power is improved by using a plurality of radio wave refraction plates including one or more refraction plates whose horizontal length is within a range of ±25% of twice the radius of the first Fresnel zone.

[0042] Fig. 11 is a diagram for explaining a method for installing a plurality of radio wave refraction plates according to the fourth embodiment. In the example shown in Fig. 11, two radio wave refraction plates, a radio wave refraction plate 14-1 and a radio wave refraction plate 14-2, are arranged side by side.

[0043] 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.

[0044] In the graph of Figure 11, 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 22B. Point P12 indicates the installation position and amount of phase change of element 24B.

[0045] As shown in FIG. 11, in this embodiment, the radio wave refraction plate 14-1 is installed so that points P1 to P3 are on a straight line 41, and the radio wave refraction plate 14-2 is installed so that points P11 and P12 are off the straight line 41.

[0046] 11, the radio wave refraction plate 14-2 is installed so that points P11 and P12 are on a straight line 42. In other words, the radio wave refraction plate 14-1 and the radio wave refraction plate 14-2 are installed so that the amount of phase change is discontinuous. In the fourth embodiment, by installing the radio wave refraction plate 14-2 so that it deviates from the straight line 41, it is possible to increase the received power of the refracted radio waves and further improve the characteristics.

[0047] The arrow between the straight lines 41 and 42 indicates the difference in the amount of phase change between the straight lines 41 and 42. The characteristics can be further improved by setting the difference in the amount of phase change between the straight lines 41 and 42 to, for example, 180°. Note that the difference in the amount of phase change between the straight lines 41 and 42 is not limited to 180°.

[0048] Fig. 12 is a schematic diagram showing a plurality of radio wave refraction plates according to the fourth embodiment. Fig. 12 shows two radio wave refraction plates, a radio wave refraction plate 14-1 and a radio wave refraction plate 14-2, arranged side by side. The radio wave refraction plate 14-1 and the radio wave refraction plate 14-2 are arranged side by side with a gap L therebetween. In Fig. 12, the geometric center of the radio wave refraction plate 14-1 and the radio wave refraction plate 14-2 is defined as a geometric center C.

[0049] Fig. 13 is a diagram showing the angular dependency of received power according to the fourth embodiment, which illustrates the angular dependency of received power due to differences in the length of the gap L between the radio wave refraction plate 14-1 and the radio wave refraction plate 14-2.

[0050] 13, the linear distance between the radio wave transmission point and the geometric center C is 50 m, the linear distance between the radio wave reception point and the geometric center C is 2 m, and the frequency of the radio waves is 28 GHz. In this case, the radius of the first Fresnel zone 30 is 0.14 m. The received power is normalized by the received power when the radio wave refraction plates 14-1 and 14-2 are not installed.

[0051] 13 shows waveforms 131, 132, and 133. Waveform 131 shows the angular dependence of the received power of a single radio wave refraction plate 14 measuring 0.27 m x 0.6 m. Waveform 132 shows the angular dependence of the received power when radio wave refraction plates 14-1 and 14-2 measuring 0.27 m x 0.3 m are arranged with a gap of 0.5 m between them. Waveform 133 shows the angular dependence of the received power when radio wave refraction plates 14-1 and 14-2 measuring 0.27 m x 0.3 m are arranged with a gap of 0.01 m between them. Waveforms 132 and 133 show the angular dependence of the received power of an arrangement example in which the amount of phase change between radio wave refraction plate 14-1 and radio wave refraction plate 14-2 is discontinuous.

[0052] Comparing waveforms 131, 132, and 133, waveforms 132 and 133 show good reception power characteristics when viewed in terms of peak values ​​of normalized reception power. That is, in the fourth embodiment, by arranging radio wave refraction plate 14-1 and radio wave refraction plate 14-2 so that the amount of phase change is discontinuous, it is possible to improve the peak value of normalized reception power.

[0053] Fifth Embodiment Next, a fifth embodiment will be described. In the fifth embodiment, when a plurality of radio wave refraction plates are arranged to improve the received power, the radio wave refraction plates are arranged so as to satisfy two conditions.

[0054] The first condition is that the multiple radio wave refraction plates are arranged side by side so that when the coordinates of each element included in the multiple radio wave refraction plates are projected onto a certain plane, the horizontal axis represents the installation position of each element and the vertical axis represents the amount of phase change [degrees], which forms a straight line.

[0055] The second condition is that the gap L between adjacent radio wave refraction plates 14-1 and 14-2 (see FIG. 12) must be set at a distance of at least five times the wavelength of the radio wave.

[0056] Fig. 14 is a diagram showing the relationship between the gap between multiple radio wave refraction plates and received power according to the fifth embodiment. Fig. 14 is a graph showing the change in normalized received power when the gap L between the radio wave refraction plates 14-1 and 14-2 (see Fig. 12) is changed. In Fig. 14, the horizontal axis represents the distance [mm] between the two radio wave refraction plates, and the vertical axis represents the normalized received power [dB] at the peak.

[0057] FIG. 14 shows graphs 141, 142, and a line 143. Graph 141 shows the normalized received power of a single radio wave refraction plate 14 measuring 0.27 m by 0.6 m in the height direction and horizontal direction. Graph 142 shows the normalized received power when the distance between two radio wave refraction plates 14 measuring 0.27 m by 0.3 m in the height direction and horizontal direction is changed. Line 143 shows the normalized received power at peak when the distance between the two radio wave refraction plates 14 is five times the wavelength of the received radio wave. As shown in FIG. 14 , when the distance between the two radio wave refraction plates 14 is five times the wavelength of the received radio wave, graph 142 exceeds the normalized received power at peak of graph 141. That is, in the fifth embodiment, by spacing the two radio wave refraction plates 14 by five wavelengths or more, the normalized receiving power characteristics can be improved compared to when a single large radio wave refraction plate is used.

[0058] 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.

[0059] REFERENCE SIGNS LIST 1 communication system 10 base station 11 obstacle 12 terminal 14 radio wave refraction plate 20 substrate 22, 24, 26, 28 element 30 first Fresnel zone 32 second Fresnel zone 34 third Fresnel zone 36 fourth Fresnel zone

Claims

1. A radio wave control board that is installed between a transmitter that transmits radio waves and a receiver that receives the radio waves, the radio wave control plate has at least one of a length in a first direction parallel to the refracting or reflecting surface of the radio wave and a length in a second direction perpendicular to the first direction, the length being 75% or more and 125% or less of twice the radius of a circular area defined by a positional relationship between the transmitter, the radio wave control plate, and the receiver; If the distance between the transmitter and the center of the radio wave control plate is dt, the distance between the center of the refracting surface or the reflecting surface and the receiver is dr, and the wavelength is λ, the radius r of the circular area satisfies the following formula (1-1): Radio control board. [0010]

2. The length in the second direction is 75% or more and 125% or less of twice the radius of the circular region, and the length in the first direction is longer than the length in the second direction. The radio wave control board according to claim 1 .

3. The length in the first direction is 75% or more and 125% or less of twice the radius of the circular region, and the length in the second direction is longer than the length in the first direction. The radio wave control board according to claim 1 .

4. the first direction is a horizontal direction of the radio wave control plate, The second direction is a height direction of the radio wave control plate. The radio wave control board according to claim 1 .

5. A transmitter for transmitting radio waves; a plurality of radio wave control plates for refracting or reflecting the radio waves transmitted from the transmitter; a receiver that receives the radio waves refracted or reflected by the plurality of radio wave control plates; Including, the radio wave control plate has at least one of a length in a first direction parallel to the refracting or reflecting surface of the radio wave and a length in a second direction perpendicular to the first direction, the length being 75% or more and 125% or less of twice the radius of a circular area defined by a positional relationship between the transmitter, the radio wave control plate, and the receiver; If the distance between the transmitter and the center of the radio wave control plate is dt, the distance between the center of the refracting surface or the reflecting surface and the receiver is dr, and the wavelength is λ, the radius r of the circular area satisfies the following formula (1-1): Communication systems. [0025]

6. When the coordinates of each of the plurality of elements included in the radio wave control plate are plotted on a graph in which the horizontal axis indicates position and the vertical axis indicates transmission phase, the plurality of radio wave control plates are disposed so as not to be on a straight line.

6. The communication system according to claim 5.

7. The plurality of radio wave control plates are arranged such that the adjacent radio wave control plates are spaced apart from each other by a gap of at least five times the wavelength of the radio waves.

6. The communication system according to claim 5.

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