Reflectors and reflectors

Abstract

To reduce variations in the intensity of reflected waves depending on the position of a reflector.SOLUTION: A reflector 1 includes a plurality of reflecting elements 11 that reflect incident radio waves as reflected waves with different phases, respectively, and in the reflection phase characteristic showing the relationship between the position of the plurality of reflecting elements 11 in the reference direction in which the plurality of reflecting elements 11 are arranged and the reflection phase which is the phase of the reflected wave by each of the plurality of reflecting elements 11, the plurality of reflecting elements 11 are configured such that the reflection phase changes continuously with respect to changes in the positions of the plurality of reflecting elements 11.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a reflector that reflects radio waves and a reflecting device that includes the reflector. [Background technology]

[0002] BACKGROUND ART Reflectors having a plurality of reflecting elements are known in the art (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-141359 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional reflectors, the reflection phases of two adjacent regions among the multiple regions included in the reflector are discontinuously different values. When the reflection phases of two adjacent regions are discontinuously different values, the reflected wave of the radio wave in the first region and the reflected wave of the radio wave in the second region cancel each other out, resulting in a problem in which the power of the reflected wave becomes small near the boundary between the two regions.

[0005] The present invention has been made in view of these points, and has as its object to reduce variations in the intensity of reflected waves depending on the position of the reflector. [Means for solving the problem]

[0006] The reflector of the first aspect of the present invention has a plurality of reflecting elements that reflect incident radio waves as reflected waves of different phases, and the plurality of reflecting elements are configured so that the reflection phase changes continuously with changes in the position of the plurality of reflecting elements in a reflection phase characteristic that indicates the relationship between the positions of the plurality of reflecting elements in a reference direction in which the plurality of reflecting elements are arranged and the reflection phase, which is the phase of the reflected wave by each of the plurality of reflecting elements.

[0007] The reflector may have a plurality of regions each having a different reflection direction, and the reflection phase in the plurality of regions may change linearly with respect to the positions of the plurality of reflecting elements.

[0008] The curve representing the reflection phase characteristic may be a part of a circular arc, in which case, when the beam width of the reflector is θ, the width of the reflector in a reference direction is 2W, and the position in the reference direction is x, the reflection phase at position x is expressed as

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[0009] The radiation direction of the reflected wave at the center position of the range in which the reflector radiates the reflected wave may be a direction orthogonal to the reference direction. The radiation direction of the reflected wave at the center position of the range in which the reflector radiates the reflected wave may be a direction different from the direction orthogonal to the reference direction.

[0010] A second aspect of the reflection device of the present invention comprises the above-mentioned reflector and a control device that controls the plurality of reflection elements, wherein each of the plurality of reflection elements changes the phase of a reflected wave by a voltage applied by the control device, and the control device accepts settings for the reflection phase characteristics and applies voltages determined based on the accepted reflection phase characteristics to the plurality of reflection elements.

[0011] The control device may accept a setting of the angle between the radiation direction of the reflected wave at the center position of the range in which the reflector radiates the reflected wave and the reference direction, and may apply a voltage determined based on the accepted angle to the multiple reflecting elements. [Effects of the Invention]

[0012] According to the present invention, it is possible to reduce variations in the intensity of reflected waves depending on the position of the reflector. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a diagram for explaining an outline of a reflecting device S. FIG. [Figure 2] FIG. 2 is a diagram showing an outline of the configuration of a reflector 1. [Figure 3] 10 is a diagram showing the relationship between the number P of regions R of a reflector 1 and the beam width HPBW of a reflected wave. FIG. [Figure 4] 10 is a diagram showing the relationship between the reflection direction and the intensity of the reflected wave in a plurality of regions R. FIG. [Figure 5] 3 is a diagram showing an example of the reflection phase characteristic of the reflector 1. FIG. [Figure 6] FIG. 10 is a diagram showing the results of a simulation of the relationship between the angle and the reflection cross-sectional area of ​​the reflector 1. [Figure 7] 10 is a diagram showing the relationship between the angle and the reflection cross-sectional area when the number of regions R that the reflector 1 has is different. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] [Outline of Reflector S] FIG. 1 is a diagram illustrating an overview of a reflecting device S. The reflecting device S is a device that can change the direction in which incident radio waves are reflected. The reflecting device S includes a reflecting plate 1 and a control device 2. The reflecting plate 1 has a plurality of reflecting elements 11. The plurality of reflecting elements 11 are, for example, arranged at equal intervals in a first direction and a second direction perpendicular to the first direction.

[0015] At least some of the plurality of reflecting elements 11 reflect the incident radio waves as reflected waves with different phases. Each of the plurality of reflecting elements 11 changes the phase of the reflected wave in response to a voltage applied by the external device 2.

[0016] The reflector 1 reflects radio waves transmitted from a radio wave transmission source 3 (for example, a base station of a mobile phone network) toward the terminal 4. When the terminal 4 moves, the reflector 1 reflects the radio waves toward the position of the terminal 4, for example, based on the control of the control device 2 that recognizes the position of the terminal 4 based on position information transmitted from the terminal 4. The reflector 1 can change the direction in which it reflects the radio waves based on the voltage applied to the multiple reflecting elements 11 by the control device 2.

[0017] The control device 2 includes, for example, a processor and a power supply that outputs a voltage determined by the processor. The control device 2 changes the voltage applied to each of the plurality of reflective elements 11 of the reflector 1, thereby changing the delay time when each of the plurality of reflective elements 11 reflects the incident radio wave. Since the plurality of reflective elements 11 reflect the radio wave at different times, the direction of the reflected wave is determined by the timing at which the plurality of reflective elements 11 reflect the radio wave.

[0018] In the example shown in FIG. 1, while the terminal 4 is at position A, the control device 2 controls the reflector 1 so that the reflector 1 reflects radio waves toward position A. When the terminal 4 moves to position B, the control device 2 controls the reflector 1 so that the reflector 1 reflects radio waves toward position B.

[0019] [Reflector 1 configuration] FIG. 2 is a diagram showing an outline of the configuration of reflector 1. As shown in FIG. 2, reflector 1 has multiple regions R1, R2, and R3, each of which reflects radio waves in a different direction. In the example shown in FIG. 2, region R1 reflects radio waves in a direction at 50 degrees to the incident direction, region R2 reflects radio waves in a direction at 60 degrees to the incident direction, and region R3 reflects radio waves in a direction at 70 degrees to the incident direction. By having reflector 1 reflect radio waves in multiple directions in this way, the beam width of the reflected waves can be widened.

[0020] 2, in this specification, the x direction is defined as the reference direction in which the reflection direction changes in reflector 1. Also, in this specification, the reflection direction of radio waves is expressed by the reflection angle, which is the angle between the incident direction and the reflection direction.

[0021] Fig. 3 is a diagram showing the relationship between the number P of regions R of reflector 1 and the beam width HPBW of the reflected wave. The horizontal axis of Fig. 3 represents the width Md of reflector 1, and the vertical axis represents the beam width HPBW. The beam width, the number P of regions R of reflector 1, and the width Md of reflector 1 have a relationship expressed by the following formula (1).

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[0022] However, if the phases of the reflected waves near the boundaries between multiple regions R are different, the reflected waves from adjacent regions R cancel each other out, resulting in a problem of reduced reflected wave intensity. Figure 4 is a diagram to explain an overview of this problem, showing the relationship between the reflection angle and the intensity of the reflected wave for multiple regions R. The horizontal axis of Figure 4 represents the reflection angle for each region R, and the vertical axis represents the reflection cross-sectional area corresponding to the intensity of the reflected wave. #1 represents the intensity of the reflected wave from region R1, and #2 represents the intensity of the reflected wave from region R2 adjacent to region R1.

[0023] As shown in Figure 4(a), the median reflection angle of the reflected wave from region R1 is different from that of region R2, but the relationship between the angle and the reflection cross-sectional area is the same. In the area where the reflection angle of region R1 overlaps with the reflection angle of region R2, if the phase of the reflected wave from region R1 is not the same as that of the reflected wave from region R2, the reflected wave from region R1 and the reflected wave from region R2 will cancel each other out. As a result, as shown in Figure 4(b), the reflection cross-sectional area will be smaller in the area where the reflection angle of region R1 overlaps with the reflection angle of region R2.

[0024] To solve this problem, the reflector 1 is characterized in that the reflecting elements 11 are configured so that the reflection phase, which is the phase of the wave reflected by each of the reflecting elements 11, changes continuously with the change in the positions of the reflecting elements 11 in the reflection phase characteristic, which indicates the relationship between the positions of the reflecting elements 11 in a reference direction in which the reflecting elements 11 are arranged and the reflection phase, which is the phase of the wave reflected by each of the reflecting elements 11. The reflection phase in the multiple regions R that make up the reflector 1 changes linearly with the positions of the multiple reflecting elements 11, for example.

[0025] Fig. 5 is a diagram showing an example of the reflection phase characteristics of the reflector 1. The horizontal axis of Fig. 5 represents the position in the x direction of the reflector 1 shown in Fig. 2, and the vertical axis represents the reflection phase. The reflection phase is equal to or greater than 0 and less than 2π.

[0026] FIG. 5(a) shows the reflection phase characteristics when the reflector 1 has four regions R. In FIG. 5(a), four line segments are connected, each representing the relationship between the position in the x direction and the reflection phase in region R1, region R2, region R3, and region R4. Since adjacent line segments are connected, it can be seen that the reflection phases at the boundary positions of the multiple regions R are consistent, and the multiple reflecting elements 11 are configured so that the reflection phase changes continuously with changes in the positions of the multiple reflecting elements 11. By configuring the reflector 1 to have such reflection phase characteristics, reflected waves are less likely to be canceled out at the boundary positions of adjacent regions R, preventing a decrease in the reflection cross-sectional area as shown in FIG. 4(b).

[0027] The plurality of reflecting elements 11 may be configured in advance so that the reflector 1 has the reflection phase characteristic shown in Fig. 5(a), but in this embodiment, the control device 2 applies a voltage to each of the plurality of reflecting elements 11 so that the reflector 1 has the reflection phase characteristic shown in Fig. 5(a). By configuring the reflector 1 and the control device 2 in this way, the reflector 1 can flexibly change the reflection phase characteristic.

[0028] 5(b) shows an example in which the curve representing the reflection phase characteristic is a part of a circular arc. This example corresponds to the case in which the number P of regions R in formula (1) is infinite, and when the beam width of the reflector is θ, the width of the reflector in the reference direction is 2W, and the position in the reference direction is x, the reflection phase at position x is expressed by the following formula (2).

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[0029] The reflector 1 is configured so that the curve showing the reflection phase characteristic of the reflector 1 is part of an arc, so that the reflected waves from a plurality of adjacent reflecting elements 11 are not canceled out, making it possible to maintain the reflection cross-sectional area at an equal level over a wide range.

[0030] In the examples shown in Figures 5(a) and 5(b), the radiation direction of the reflected wave at the center position of the range in which the reflector 1 radiates the reflected wave is a direction perpendicular to the reference direction (i.e., upward in Figure 5), but the radiation direction of the reflected wave at the center position of the range in which the reflector 1 radiates the reflected wave may be a direction different from the direction perpendicular to the reference direction.

[0031] Figure 5(c) shows a reflection phase characteristic in which the radiation direction of the reflected wave at the center position of the range in which reflector 1 radiates the reflected wave is tilted at an angle φ with respect to the direction perpendicular to the reference direction (the z-axis direction in Figure 2). By determining the voltage to be applied to each of the multiple reflecting elements 11 so as to achieve the reflection phase characteristic shown in Figure 5(c), the control device 2 can maintain the reflection cross-sectional area at an equivalent level over a wide range and control the direction of the reflected wave to a desired direction.

[0032] 5 is the x-axis direction shown in FIG. 2, but the reference direction may be the y-axis, and the reflection phase characteristic may be a characteristic representing the reflection phase in the y-axis direction. Also, the reflection phase characteristic may be a characteristic representing the reflection phase at each of a plurality of positions in the xy plane.

[0033] [Configuration of control device 2] The control device 2 may receive a setting for the reflection phase characteristic and apply a voltage determined based on the received reflection phase characteristic to the plurality of reflecting elements 11. The control device 2 has, for example, a display that displays an operation screen for the user to set the desired reflection phase characteristic, or a communication interface that receives setting contents transmitted from an external device, and acquires data indicating the reflection phase characteristic set by the user. The control device 2 determines the value of the voltage to be applied to each of the plurality of reflecting elements 11 based on the acquired data. With the control device 2 configured in this way, it becomes possible for the reflector 1 to reflect radio waves so as to have the reflection phase characteristic desired by the user.

[0034] The control device 2 may receive a setting of the angle between the radiation direction of the reflected wave at the center position of the range in which the reflector 1 radiates the reflected wave and the reference direction, and apply a voltage determined based on the received angle to the plurality of reflecting elements 11. By configuring the control device 2 in this way, it becomes possible for the reflector 1 to reflect radio waves in a direction desired by the user, as shown in Fig. 5(c).

[0035] [Simulation Results] Fig. 6 is a diagram showing the results of a simulation of the relationship between the angle and the reflection cross-sectional area of ​​the reflector 1. The characteristics shown in Fig. 6 are for a case where the reflector 1 has two regions R and the reflection angle is 45°. The dotted line in Fig. 6 shows the reflection cross-sectional area when the phases at the boundary positions of the two regions R are different. As the dotted line shows, the reflection cross-sectional area decreases at a reflection angle of 45°.

[0036] The solid line in Fig. 6 shows the reflection cross-sectional area when the phase is the same at the boundary position of the two regions R. In the solid line, the reflection cross-sectional area does not decrease at a reflection angle of 45°, and is maintained at approximately the same level in the range of 42.5° to 47.5°.

[0037] Fig. 7 is a diagram showing the relationship between the angle and the reflection cross-sectional area when the reflector 1 has different numbers of regions R. Fig. 7(a) shows the reflection cross-sectional area when the reflector 1 has three regions R. Fig. 7(b) shows the reflection cross-sectional area when the reflector 1 has four regions R.

[0038] The dashed lines in Figure 7(a) indicate the case where the median reflection angles of the three regions R are 43°, 45°, and 47°, respectively. The dotted lines indicate the case where the median reflection angles of the three regions R are 41°, 45°, and 48°, respectively. The solid lines indicate the case where the median reflection angles of the three regions R are 39°, 45°, and 51°, respectively. It can be seen that the greater the gap between the median reflection angles of the multiple regions R, the greater the range of angles over which the reflection cross-sectional area of ​​the reflector 1 is at the same level.

[0039] The dashed lines in Figure 7(b) indicate cases where the median reflection angles of the four regions R are 39°, 43°, 47°, and 51°, respectively. The dotted lines indicate cases where the median reflection angles of the four regions R are 36°, 42°, 48°, and 54°, respectively. The solid lines indicate cases where the median reflection angles of the four regions R are 33°, 41°, 49°, and 57°, respectively. In this example as well, it can be seen that the greater the gap between the median reflection angles of the multiple regions R, the greater the range of angles over which the reflection cross-sectional area of ​​the reflector 1 is at the same level.

[0040] [Effect of Reflector 1] As described above, the reflector 1 has a plurality of reflecting elements 11 that reflect incident radio waves as reflected waves with different phases. The reflecting elements 11 are configured so that the reflection phase changes continuously with changes in the positions of the reflecting elements 11 in the reflection phase characteristic, which indicates the relationship between the positions of the reflecting elements 11 in the reference direction in which the reflecting elements 11 are arranged and the reflection phase, which is the phase of the wave reflected by each of the reflecting elements 11. By configuring the reflector 1 in this way, it is possible to reduce variations in the intensity of the reflected wave depending on the position on the reflector 1.

[0041] Furthermore, this invention will make it possible to contribute to Goal 9 of the United Nations' Sustainable Development Goals (SDGs), which is "Build resilient infrastructure, promote inclusive and sustainable industrialization, and promote innovation and resilience."

[0042] The present invention has been described above using embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. For example, all or part of the device can be configured by functionally or physically distributing or integrating any unit. Furthermore, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effects of the new embodiments resulting from the combination also have the effects of the original embodiments. [Explanation of symbols]

[0043] 1 Reflector 11 Reflective element 2. Control device 3. Source 4. Terminal

Claims

1. It has a plurality of reflecting elements that reflect incident radio waves as reflected waves with different phases, the plurality of reflecting elements are configured such that the reflection phase changes continuously with changes in the positions of the plurality of reflecting elements in a reflection phase characteristic that indicates a relationship between the positions of the plurality of reflecting elements in a reference direction in which the plurality of reflecting elements are arranged and a reflection phase that is the phase of the reflected wave by each of the plurality of reflecting elements, the reflection phase characteristic being a part of an arc; Reflector.

2. the reflector has a plurality of regions each having a different reflection direction, the reflection phase in the plurality of regions varies linearly with respect to the positions of the plurality of reflective elements; The reflector according to claim 1 .

3. When the beam width of the reflector is θ, the width of the reflector in the reference direction is 2W, and the position in the reference direction is x, the reflection phase at the position x is expressed as follows: [Equation 1] represented by The reflector according to claim 1 .

4. A reflector according to any one of claims 1 to 3; a control device for controlling the plurality of reflecting elements; and each of the plurality of reflecting elements changes a phase of a reflected wave in response to a voltage applied by the control device; the control device receives a setting of the reflection phase characteristic, and applies a voltage determined based on the received reflection phase characteristic to the plurality of reflection elements; Reflector.

5. the control device receives a setting of an angle between the radiation direction of the reflected wave at a center position of a range in which the reflector radiates the reflected wave and the reference direction, and applies a voltage determined based on the received angle to the plurality of reflecting elements.

5. The reflector according to claim 4.

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