Electromagnetic wave control plate

Abstract

An electromagnetic wave control plate capable of emitting incident electromagnetic waves in a predetermined direction, the electromagnetic wave control plate including: a plurality of first unit structures capable of setting a first change amount and a second change amount different from the first change amount, i.e., two values, as amounts of phase change with respect to the incident electromagnetic waves; and a plurality of second unit structures capable of setting a third change amount different from the first change amount and the second change amount, and a fourth change amount different from the first change amount, the second change amount, and the third change amount, i.e., two values, as amounts of phase change with respect to the incident electromagnetic waves. The plurality of first unit structures are positioned in a first region. The plurality of second unit structures are positioned in a second region different from the first region.

Description

Radio Control Board

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

[0002] In signal processing using a phased array antenna, there are known techniques for suppressing the intensity of quantization lobes relative to the main lobe. For example, Patent Document 1 discloses a technique for reducing quantization lobes simply and at low cost. Other techniques include those described in Non-Patent Document 1.

[0003] Japanese Patent Application Laid-Open No. 2008-236740

[0004] J. Yin, Q. Wu, Q. Lou, H. Wang, Z. N. Chen and W. Hong, "Single-Beam 1 Bit Reflective Metasurface Using Prephased Unit Cells for Normally Incident Plane Waves," in IEEE Transactions on Antennas and Propagation, vol. 68, no. 7, pp. 5496-5504, July 2020, doi: 10.1109 / TAP.2020.2978285

[0005] The radio wave control board of the present disclosure is a radio wave control board capable of emitting incident radio waves in a predetermined direction, and includes a plurality of first unit structures to which two values ​​can be set as the phase change amount for the incident radio waves: a first change amount and a second change amount different from the first change amount; and a plurality of second unit structures to which two values ​​can be set as the phase change amount for the incident radio waves: a third change amount different from the first change amount and the second change amount, and a fourth change amount different from the first change amount, the second change amount, and the third change amount, wherein the plurality of first unit structures are arranged in a first region, and the plurality of second unit structures are arranged in a second region different from the first region.

[0006] FIG. 1 is a diagram illustrating the shape of a beam emitted by a radio wave control plate according to a comparative example. FIG. 2 is a diagram illustrating an example of the configuration of a radio wave control plate according to the first embodiment. FIG. 3 is a diagram illustrating the shape of a beam emitted by a radio wave control plate according to the first embodiment. FIG. 4 is a diagram illustrating an example of the configuration of a radio wave control plate according to the second embodiment. FIG. 5 is a diagram illustrating the boundary between the first region and the second region according to the second embodiment. FIG. 6 is a diagram illustrating the relationship between the quantization lobe and the slope between the first region and the second region according to the second embodiment. FIG. 7 is a diagram illustrating the relationship between the beam intensity and the first region and the second region according to the second embodiment. FIG. 8 is a diagram illustrating an example of the configuration of a radio wave control plate according to the third embodiment. FIG. 9 is a diagram illustrating the relationship between the beam shape and the area of ​​the first region and the second region according to the third embodiment. FIG. 10 is a diagram illustrating the relationship between the quantization lobe and the proportion of the area of ​​the first region according to the third embodiment. FIG. 11 is a diagram illustrating an example of the configuration of a radio wave control plate according to the fourth embodiment. FIG. 12 is a diagram illustrating the relationship between the beam shape according to the fourth embodiment and the number of divisions of the regions of the radio wave control plate. Fig. 13 is a diagram for explaining the relationship between the beam shape and the phase change amount according to the fifth embodiment. Fig. 14 is a diagram for explaining the relationship between the quantization lobe and the phase shift amount of the phase change amount of the second unit structure according to the fourth embodiment.

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

[0008] The radio wave control plate is a component configured to be able to reflect or refract incident radio waves at a predetermined angle. For example, when the radio wave control plate receives radio waves transmitted from a base station, it reflects or refracts the radio waves at a predetermined angle. The radio wave control plate has a plurality of unit structures, each of which has a set amount of change (phase change amount) relative to the phase of the incident radio waves, arranged two-dimensionally. The unit structures are made of, for example, metamaterial.

[0009] Comparative Example The shape of a beam emitted by a radio wave control board according to a comparative example will be described with reference to Fig. 1. Fig. 1 is a diagram for explaining the shape of a beam emitted by a radio wave control board according to a comparative example.

[0010] FIG. 1 is a diagram illustrating the shape of a beam emitted by a radio wave control plate according to a comparative example. In FIG. 1, the horizontal axis represents the beam emission direction [deg], and the vertical axis represents normalized beam intensity [dB]. In the example shown in FIG. 1, each unit structure included in the radio wave control plate can be set to have a phase change amount of 0° or 180°. Also, in the example shown in FIG. 1, the radio wave control plate emits a beam in a direction 30° from the normal to the radio wave control plate (the reflection angle is 30°).

[0011] 1 , in the comparative example, a quantization lobe of approximately the same intensity as the main lobe occurs in the −30° direction relative to the main lobe in the 30° direction. In the present disclosure, a radio wave control plate having a unit structure capable of setting the phase change amount to two different values ​​suppresses the intensity of the quantization lobe with a simple configuration.

[0012] [First embodiment] (Radio wave control board) A configuration example of a radio wave control board according to the first embodiment will be described with reference to Fig. 2. Fig. 2 is a diagram showing a configuration example of a radio wave control board according to the first embodiment.

[0013] As shown in Fig. 2(a), the radio wave control plate 1 includes a plurality of first unit structures 11 and a plurality of second unit structures 12. Fig. 2(a) shows an example of the arrangement of the plurality of first unit structures 11 and the plurality of second unit structures 12.

[0014] The first unit structure 11 is a metasurface element that can set two different amounts of change as the phase change amount. Such an element can be realized with a simpler structure than a metasurface element that can set three or more amounts of change. The first unit structure 11 can be set, for example, to 0° or 180° as the phase change amount. In this case, an example of the first amount of change is 0°. An example of the second amount of change is 180°. The first unit structure 11 is arranged two-dimensionally in the first region R1, which is the upper half of the radio wave control plate 1.

[0015] The second unit structure 12 is a metasurface element that can set the phase change amount with respect to the incident wave to two different values ​​different from the phase change amount (first change amount and second change amount) of the first unit structure 11. For example, by changing the thickness of the second unit structure 12 from that of the first unit structure 11, a phase change amount different from that of the first unit structure 11 can be set. For example, the phase change amount of the second unit structure 12 can be set to 90° or 270°. An example of the third change amount is 90°. An example of the fourth change amount is 270°. The second unit structures 12 are arranged two-dimensionally in a second region R2, which is the lower half region of the radio wave control plate 1.

[0016] FIG. 2B shows an example of setting the amount of phase change of the first unit structure 11 and the second unit structure 12 according to the first embodiment.

[0017] 2B, the phase change amount of each of the plurality of first unit structures 11 is set to have a gradient along the X-axis direction (hereinafter, the gradient of the phase change amount is also referred to as the phase gradient). That is, the phase change amount of each of the plurality of first unit structures 11 is set so that the X-axis direction is the direction of the phase gradient in the first region R1. For example, the phase change amount of each of the plurality of first unit structures 11 is set to 0° or 180° for every predetermined number of first unit structures 11 in the X-axis direction. The phase change amount of each of the plurality of first unit structures 11 is set to the same value in the Y-axis direction.

[0018] The phase change amount of each of the plurality of second unit structures 12 is set to have a phase gradient along the X-axis direction. That is, the phase change amount of each of the second unit structures 12 is set so that the X-axis direction is the direction of the phase gradient in the second region R2. For example, the phase change amount of each of the plurality of second unit structures 12 is set to 90° or 270° in the X-axis direction for each predetermined number of second unit structures 12. The phase change amount of each of the plurality of second unit structures 12 is set to the same value in the Y-axis direction.

[0019] The phase change amount of each first unit structure 11 and the phase change amount of each second unit structure 12 are set so that the phase gradient in the X-axis direction of the first region R1 and the phase gradient in the X-axis direction of the second region R2 both approach the ideal phase gradient expressed by the following equation (1): Phase gradient = k sin θ ０ ...(1) Furthermore, the distribution Ψ of the phase change amount in the first region and the second region ｎ can be expressed by the following equation (2): ｎ = kx ｎ sinθ ０ +α... (2)

[0020] Here, k is the wave number of the incident radio wave, and if the wavelength of the incident radio wave is λ, then k can be expressed as k = 2π / λ. ０ is the reflection angle (a predetermined reflection angle in the radio wave control plate 1) when the incident radio wave is reflected by the radio wave control plate 1. n represents the element number in the direction of the phase gradient of the first unit structure 11 or the second unit structure 12. ｎ represents the position of the first unit structure 11 or the second unit structure 12 in the direction of the phase gradient. ｎ When the distance between the first unit structures 11 or the second unit structures 12 adjacent to each other in the X-axis direction is p, x ｎ = np, where α is a constant term, and α in the first region may differ from α in the second region, but ideally they should match.

[0021] Furthermore, as shown in FIG. 2B, it is preferable that the boundary of the phase change amount in the first region R1 (e.g., the boundary between 0° and 180°) and the boundary of the phase change amount in the second region R2 (e.g., the boundary between 90° and 270°) are not on a straight line.

[0022] Furthermore, it is preferable to set the phase change amount of each first unit structure 11 and the phase change amount of each second unit structure 12 so that the constant term α in the first region R1 of Equation (2) and the constant term α in the second region R2 of Equation (2) match as closely as possible. Furthermore, it is preferable that the boundary between the first region R1 and the second region R2 is parallel to the X-axis direction. In other words, it is desirable that the boundary between the first region R1 and the second region R2 is parallel to the direction of the phase gradient. Furthermore, it is preferable that the area of ​​the first region R1 and the area of ​​the second region R2 are the same.

[0023] (Beam Shape) The shape of the beam emitted by the radio wave control plate according to the first embodiment will be described with reference to FIG. 3. FIG. 3 is a diagram for explaining the shape of the beam emitted by the radio wave control plate according to the first embodiment. In FIG. 3, the horizontal axis represents the emission direction [deg] of the radio wave emitted by the radio wave control plate, and the vertical axis represents the normalized beam intensity [dB] of the beam emitted by the radio wave control plate. In the example shown in FIG. 3, the radio wave control plate 1 emits a beam in a direction of 30° (predetermined reflection angle θ ０ is 30°).

[0024] 3, in the first embodiment, the intensity of the quantization lobe in the −30° direction is suppressed relative to the main lobe in the 30° direction. That is, in the first embodiment, the intensity of the quantization lobe can be suppressed by appropriately setting the amount of phase change of the plurality of first unit structures 11 arranged in the first region R1 and the plurality of second unit structures 12 arranged in the second region R2.

[0025] Second Embodiment A configuration example of a radio wave control board according to a second embodiment will be described with reference to Fig. 4. Fig. 4 is a diagram showing a configuration example of a radio wave control board according to the second embodiment.

[0026] 4(a), radio wave control plate 1A includes a plurality of first unit structures 11 and a plurality of second unit structures 12. The plurality of first unit structures 11 are arranged in a first region R11. The plurality of second unit structures 12 are arranged in a second region R12.

[0027] As shown in Figures 4(a) and 4(b), radio wave control plate 1A differs from radio wave control plate 1 shown in Figure 2 in that the boundary between first region R11 and second region R12 is inclined with respect to the X-axis.

[0028] The boundary between the first region and the second region according to the second embodiment will be described with reference to Fig. 5. Fig. 5 is a diagram for explaining the boundary between the first region and the second region according to the second embodiment.

[0029] 5A shows the radio wave control plate 1 of the first embodiment. The radio wave control plate 1 includes a first region R1 and a second region R2. The boundary between the first region R1 and the second region R2 is parallel to the X-axis. That is, the inclination of the boundary between the first region R1 and the second region R2 in the XY plane is zero.

[0030] 5B shows radio wave control plate 1A. Radio wave control plate 1A includes first region R11 and second region R12. The absolute value of the gradient in the XY plane of the boundary between first region R11 and second region R12 is 0.5.

[0031] 5(c) shows radio wave control plate 1B. Radio wave control plate 1B includes first region R21 and second region R22. The absolute value of the gradient of the boundary between first region R21 and second region R22 in the XY plane is assumed to be 1.

[0032] 5(d) shows radio wave control plate 1C. Radio wave control plate 1C includes first region R31 and second region R32. The absolute value of the gradient of the boundary between first region R31 and second region R32 in the XY plane is assumed to be 5.

[0033] (Beam Shape) The relationship between the quantization lobe according to the second embodiment and the slope between the first region and the second region will be described with reference to Fig. 6. Fig. 6 is a diagram for explaining the relationship between the quantization lobe according to the second embodiment and the slope between the first region and the second region.

[0034] FIG. 6(a) shows the shape of the beam emitted by radio wave control plate 1 shown in FIG. 5(a). FIG. 6(b) shows the shape of the beam emitted by radio wave control plate 1A shown in FIG. 5(b). FIG. 6(c) shows the shape of the beam emitted by radio wave control plate 1B shown in FIG. 5(c). FIG. 6(d) shows the shape of the beam emitted by radio wave control plate 1C shown in FIG. 5(d). In FIGS. 6(a) to 6(d), the horizontal axis represents the emission direction [deg] of the radio waves emitted by the radio wave control plate, and the vertical axis represents the normalized beam intensity [dB] of the beam emitted by the radio wave control plate. In the example shown in FIGS. 6(a) to 6(d), radio wave control plates 1 to 1C emit beams in a direction of 30°.

[0035] As shown in Figure 6(a), in the beam emitted by radio wave control plate 1, the intensity of the quantized lobe in the -30° direction is suppressed compared to the main lobe in the 30° direction. As shown in Figure 6(b), in the beam emitted by radio wave control plate 1A, beams with stronger intensities are generated in the -28° direction and the -32° direction compared to Figure 6(a). As shown in Figure 6(c), in the beam emitted by radio wave control plate 1B, beams with stronger intensities are generated in the -28° direction and the -32° direction compared to Figure 6(b). As shown in Figure 6(d), in the beam emitted by radio wave control plate 1C, beams with stronger intensities are generated in the -28° direction and the -32° direction compared to Figure 6(c).

[0036] The relationship between the beam intensity and the inclination between the first and second regions according to the second embodiment will be described with reference to Fig. 7. Fig. 7 is a diagram for explaining the relationship between the beam intensity and the first and second regions according to the second embodiment. In the example shown in Fig. 7, the radio wave control plate emits a beam in a 30° direction.

[0037] In FIG. 7, the horizontal axis represents the absolute value of the gradient of the boundary between the first and second regions in the XY plane, and the vertical axis represents the normalized beam intensity [dB].

[0038] Line 101 represents the beam intensity in the -30° direction. Line 102 represents the beam intensity in the -32° direction. Line 103 represents the beam intensity in the -28° direction. As line 101 shows, the intensity of the quantized lobe in the -30° direction is approximately -30 dB to -25 dB, regardless of the inclination in the XY plane of the boundary between the first and second regions. In other words, the intensity of the quantized lobe in the -30° direction is well suppressed. As lines 102 and 103 show, the beam intensities in the -32° and -28° directions approach 0 dB as the inclination in the XY plane of the boundary between the first and second regions increases.

[0039] 6 and 7 , the greater the absolute value of the tilt of the boundary between the first and second regions in the XY plane, the stronger the intensity of the beams generated in the −28° and −32° directions. Therefore, it is preferable that the tilt of the boundary between the first and second regions in the XY plane be 0. However, as described above, even if the tilt is not 0, the intensity of the quantization lobes can be suppressed compared to when this configuration is not adopted. Therefore, the boundary between the first and second regions may be tilted in the XY plane within an allowable range.

[0040] Third Embodiment A configuration example of a radio wave control board according to a third embodiment will be described with reference to Fig. 8. Fig. 8 is a diagram showing a configuration example of a radio wave control board according to the third embodiment.

[0041] As shown in Fig. 8, radio wave control plate 1D includes a first region R41 and a second region R42. Radio wave control plate 1D differs from radio wave control plate 1 shown in Fig. 2 in that the ratios of the areas of first region R41 and second region R42 to the overall area of ​​radio wave control plate 1D are different.

[0042] The relationship between the beam shape according to the third embodiment and the areas of the first and second regions will be described with reference to Fig. 9. Fig. 9 is a diagram for explaining the relationship between the beam shape according to the third embodiment and the areas of the first and second regions. In the example shown in Fig. 9, the radio wave control plate 1D emits a beam in a direction of 30°.

[0043] In Figures 9(a) to 9(c), the horizontal axis represents the emission direction [deg] of the radio waves emitted by the radio wave control plate, and the vertical axis represents the normalized beam intensity [dB] of the beam emitted by the radio wave control plate. Figure 9(a) shows the shape of the beam emitted by radio wave control plate 1D when the ratio of the area of ​​the first region R41 to the area of ​​radio wave control plate 1D in Figure 8 is 0% and the ratio of the area of ​​the second region R42 to the area of ​​radio wave control plate 1D in Figure 8 is 100%. Figure 9(b) shows the shape of the beam emitted by radio wave control plate 1D when the ratio of the area of ​​the first region R41 to the area of ​​radio wave control plate 1D in Figure 8 is 25% and the ratio of the area of ​​the second region R42 to the area of ​​radio wave control plate 1D in Figure 8. Figure 9(c) shows the shape of the beam emitted by radio wave control plate 1D when the ratio of the area of ​​the first region R41 to the area of ​​radio wave control plate 1D in Figure 8 is 50% and the ratio of the area of ​​the second region R42 to the area of ​​radio wave control plate 1D in Figure 8.

[0044] As shown in Figure 9(a), when the ratio of the area of ​​the first region R41 to the area of ​​the radio wave control plate 1D is 0% and the ratio of the area of ​​the second region R42 to the area of ​​the radio wave control plate 1D is 100%, a quantized lobe occurs in the -30° direction in the beam emitted by the radio wave control plate 1D. As shown in Figure 9(b), when the ratio of the area of ​​the first region R41 to the area of ​​the radio wave control plate 1D is 25% and the ratio of the area of ​​the second region R42 to the area of ​​the radio wave control plate 1D is 75%, the intensity of the quantized lobe occurring in the beam emitted by the radio wave control plate 1D is suppressed compared to Figure 9(a). As shown in Figure 9(c), when the ratio of the area of ​​the first region R41 to the area of ​​the radio wave control plate 1D is 50% and the ratio of the area of ​​the second region R42 to the area of ​​the radio wave control plate 1D is 50%, the intensity of the quantized lobe occurring in the beam emitted by the radio wave control plate 1D is suppressed compared to Figure 9(b).

[0045] The relationship between the quantization lobe and the area ratio of the first region according to the third embodiment will be described with reference to Fig. 10. Fig. 10 is a diagram for explaining the relationship between the quantization lobe and the area ratio of the first region according to the third embodiment.

[0046] In FIG. 10, the horizontal axis represents the ratio of the area of ​​the first region R41 to the area of ​​the radio wave control plate 1D, and the vertical axis represents the normalized beam intensity [dB] of the quantized lobe generated in the −30° direction.

[0047] 10, the beam intensity of the quantized lobe is smallest when the ratio of the area of ​​the first region R41 to the area of ​​the radio wave control plate 1D is 50%. Also, the beam intensity of the quantized lobe increases as the ratio of the area of ​​the first region R41 to the area of ​​the radio wave control plate 1D becomes smaller or larger than 50%.

[0048] That is, the ratio of the area of ​​the first region R41 to the area of ​​the radio wave control plate 1D is preferably 50%. In other words, the area of ​​the first region R41 and the area of ​​the second region R42 are preferably the same. However, as described above, even if the areas of the first region R41 and the second region R42 are not the same, the strength of the quantization lobe can be suppressed compared to a case in which this configuration is not adopted. Therefore, the ratio of the area of ​​the first region R41 to the area of ​​the radio wave control plate 1D and the ratio of the area of ​​the second region R42 to the area of ​​the radio wave control plate 1D may differ within a range in which the strength of the quantization lobe is tolerable.

[0049] [Fourth embodiment] A configuration example of a radio wave control board according to a fourth embodiment will be described with reference to Fig. 11. Fig. 11 is a diagram showing a configuration example of a radio wave control board according to the fourth embodiment.

[0050] As shown in FIG. 11( a), radio wave control plate 1E includes a first region R51, a second region R52, and a third region R53. In first region R51, a plurality of first unit structures 11 are arranged two-dimensionally. In second region R52, a plurality of second unit structures 12 are arranged two-dimensionally. In third region R53, a plurality of first unit structures 11 are arranged two-dimensionally. That is, radio wave control plate 1E differs from radio wave control plate 1 shown in FIG. 2 in that the region in which first unit structures 11 or second unit structures 12 are arranged is divided into three. It is preferable that the ratio of the area of ​​first region R51, the area of ​​second region R52, and the area of ​​third region R53 to the area of ​​radio wave control plate 1E be the same.

[0051] As shown in FIG. 11( b), radio wave control plate 1F includes a first region R61, a second region R62, a third region R63, and a fourth region R64. In first region R61, a plurality of first unit structures 11 are arranged two-dimensionally. In second region R62, a plurality of second unit structures 12 are arranged two-dimensionally. In third region R63, a plurality of first unit structures 11 are arranged two-dimensionally. In fourth region R64, a plurality of second unit structures 12 are arranged two-dimensionally. That is, radio wave control plate 1F differs from radio wave control plate 1 shown in FIG. 2 in that the region in which first unit structures 11 or second unit structures 12 are arranged is divided into four. Note that it is preferable that the proportions of the area of ​​first region R61, second region R62, third region R63, and fourth region R64 relative to the area of ​​radio wave control plate 1F are the same.

[0052] The relationship between the beam shape according to the fourth embodiment and the number of divisions of the radio wave control plate will be described with reference to Fig. 12. Fig. 12 is a diagram for explaining the relationship between the beam shape according to the fourth embodiment and the number of divisions of the radio wave control plate.

[0053] In Figure 12(a), the horizontal axis represents the emission direction [deg] of the radio waves emitted by the radio wave control plate, and the vertical axis represents the normalized beam intensity [dB] of the beam emitted by the radio wave control plate. Figure 12(a) shows the shape of the beam emitted by radio wave control plate 1E shown in Figure 11(a). In the example shown in Figure 12(a), radio wave control plate 1E emits a beam in a direction of 30°. As shown in Figure 12(a), the intensity of the quantization lobes is suppressed in the beam emitted by radio wave control plate 1E. In other words, even if the area in which first unit structures 11 or second unit structures 12 are arranged is divided into three, the fourth embodiment can suppress the intensity of the quantization lobes.

[0054] In Figure 12(b), the horizontal axis represents the emission direction [deg] of the radio waves emitted by the radio wave control plate, and the vertical axis represents the normalized beam intensity [dB] of the beam emitted by the radio wave control plate. Figure 12(b) shows the shape of the beam emitted by radio wave control plate 1F shown in Figure 11(b). In the example shown in Figure 12(b), radio wave control plate 1F emits a beam in a direction of 30°. As shown in Figure 12(b), the intensity of the quantization lobes is suppressed in the beam emitted by radio wave control plate 1F. In other words, even if the area in which first unit structures 11 or second unit structures 12 are arranged is divided into four, the fourth embodiment can suppress the intensity of the quantization lobes.

[0055] 11 and 12 illustrate examples in which the area in which the first unit structures 11 or the second unit structures 12 are arranged is divided into three and four parts, but the present disclosure is not limited thereto. In the present disclosure, the area in which the first unit structures 11 or the second unit structures 12 are arranged in the radio wave control plate may be divided into five or more parts. Even in this case, it is preferable that the area of ​​the area in which the first unit structures 11 are arranged (or the total area if the area in which the first unit structures 11 are arranged is divided into multiple parts) and the area in which the second unit structures 12 are arranged (or the total area if the area in which the second unit structures 12 are arranged is divided into multiple parts) are the same relative to the area of ​​the radio wave control plate.

[0056] Fifth Embodiment Next, a fifth embodiment will be described. In the first embodiment, the phase change amount of the first unit structure 11 is set to 0° or 180°, and the phase change amount of the second unit structure 12 is set to 90° or 180°. In the fifth embodiment, the phase may be shifted by Δ from 90° or 270°, for example, by 90°-Δ or 270°-Δ.

[0057] The relationship between the beam shape and the amount of phase change according to the fifth embodiment will be described with reference to Fig. 13. Fig. 13 is a diagram for explaining the relationship between the beam shape and the amount of phase change according to the fifth embodiment. In the example shown in Fig. 13, the radio wave control plate 1 emits a beam in a 30° direction.

[0058] In Figures 13(a) to 13(d), the horizontal axis represents the emission direction [deg] of the radio waves emitted by the radio wave control plate, and the vertical axis represents the normalized beam intensity [dB] of the beam emitted by the radio wave control plate. Figure 13(a) shows the shape of the beam emitted by the radio wave control plate 1 when Δ = 0°, i.e., the phase change amount of the second unit structure 12 is set to 90° or 270°, in the example shown in Figure 2. Figure 13(b) shows the shape of the beam emitted by the radio wave control plate 1 when Δ = 10°, i.e., the phase change amount of the second unit structure 12 is set to 80° or 260°, in the example shown in Figure 2. Figure 13(c) shows the shape of the beam emitted by the radio wave control plate 1 when Δ = 30°, i.e., the phase change amount of the second unit structure 12 is set to 60° or 240°, in the example shown in Figure 2. Figure 13 (d) shows the shape of the beam emitted by the radio wave control plate 1 when, in the example shown in Figure 2, Δ = 60°, i.e., the phase change amount of the second unit structure 12 is set to 30° or 210°.

[0059] As shown in Fig. 13(a), when Δ=0°, the intensity of the quantization lobe occurring in the -30° direction is suppressed. As shown in Fig. 13(b), when Δ=10°, the intensity of the quantization lobe occurring in the -30° direction is stronger than when Δ=0°, but is still sufficiently suppressed. As shown in Fig. 13(c), when Δ=30°, the intensity of the quantization lobe occurring in the -30° direction is stronger than when Δ=10°.

[0060] The relationship between the quantization lobes and the phase shift amount of the phase change amount of the second unit structure according to the fourth embodiment will be described with reference to Fig. 14. Fig. 14 is a diagram for explaining the relationship between the quantization lobes and the phase shift amount of the phase change amount of the second unit structure according to the fourth embodiment.

[0061] In FIG. 14, the horizontal axis represents the phase shift amount Δ [deg], and the vertical axis represents the normalized beam intensity [dB] of the quantized lobe generated in the −30° direction.

[0062] As shown in FIG. 14 , as the phase shift amount Δ increases, the intensity of the quantization lobe increases. Therefore, it is preferable that the phase shift amount Δ is 0°. In other words, it is preferable that the second change amount is set to the first change amount + 180°, the third change amount is set to the first change amount + 90°, and the fourth change amount is set to the first change amount + 270°. However, the phase change amount set for the second unit structure 12 may be shifted from 90° or 270° within an allowable range. For example, if an intensity change of about −10 dB can be used, in the case of FIG. 14 , the phase shift amount Δ may be shifted up to about 20°.

[0063] It is also possible to combine the technical ideas shown in the above-described embodiments. For example, the region in which the first unit structures 11 are arranged may be divided into a plurality of regions, and the boundary between the region in which the first unit structures 11 are arranged and the region in which the second unit structures 12 are arranged may not be parallel to the direction of the phase gradient.

[0064] The present disclosure may also be configured as follows: (1) A radio wave control plate capable of emitting incident radio waves in a predetermined direction, comprising: a plurality of first unit structures to which two values, a first change amount and a second change amount different from the first change amount, can be set as a phase change amount for the incident radio waves; and a plurality of second unit structures to which two values, a third change amount different from the first change amount and the second change amount, and a fourth change amount different from the first change amount, the second change amount, and the third change amount, can be set as a phase change amount for the incident radio waves, wherein the plurality of first unit structures are arranged in a first region, and the plurality of second unit structures are arranged in a second region different from the first region. (2) The radio wave control board according to (1), wherein a boundary between the first unit structure, whose phase change amount is set to the first change amount, and the first unit structure, whose phase change amount is set to the second change amount, and a boundary between the second unit structure, whose phase change amount is set to the third change amount, and the second unit structure, whose phase change amount is set to the fourth change amount, are not aligned in a straight line. (3) The radio wave control board according to (1), wherein the boundary between the first region and the second region is parallel to the direction of the phase gradient of the first region and the second region. (4) The radio wave control board according to any one of (1) to (3), wherein the second change amount is set to the first change amount + 180°, the third change amount is set to the first change amount + 90°, and the fourth change amount is set to the first change amount + 270°. (5) The radio wave control board according to any one of (1) to (4), wherein an area of ​​the region in which the first unit structure is arranged is equal to an area of ​​the region in which the second region is arranged. (6) The radio wave control plate according to any one of (1) to (5), wherein at least one of the first region and the second region is divided into a plurality of regions. (7) When the predetermined direction is an angle θ0 and k is the wave number of the incident radio wave, the amount of phase change of each of the plurality of first unit structures is such that the phase gradient of the first region is k sinθ ０ The phase change amount of each of the plurality of second unit structures is set so that the phase gradient of the second region is closest to k sinθ０ (8) The radio wave control board according to any one of (1) to (7), wherein the phase change amounts of the first unit structures and the second unit structures are set so that a distribution of the phase change amounts in the first region and a distribution of the phase change amounts in the second region are set as close as possible to each other.

[0065] 1, 1A, 1B, 1C, 1D, 1E, 1F Radio wave control panel 11 First unit structure 12 Second unit structure R1, R11, R21, R31, R41, R51, R61 First region R2, R12, R22, R32, R42, R52, R62 Second region R53, R63 Third region R64 Fourth region

Claims

1. A radio wave control board capable of emitting incident radio waves in a predetermined direction, comprising: a plurality of first unit structures to which two values ​​can be set as the amount of phase change for the incident radio waves: a first change amount and a second change amount different from the first change amount; and a plurality of second unit structures to which two values ​​can be set as the amount of phase change for the incident radio waves: a third change amount different from the first change amount and the second change amount, and a fourth change amount different from the first change amount, the second change amount, and the third change amount; wherein the plurality of first unit structures are arranged in a first region, and the plurality of second unit structures are arranged in a second region different from the first region.

2. A radio wave control board as described in claim 1, wherein the boundary between the first unit structure whose phase change amount is set to the first change amount and the first unit structure whose phase change amount is set to the second change amount, and the boundary between the second unit structure whose phase change amount is set to the third change amount and the second unit structure whose phase change amount is set to the fourth change amount are not aligned in a straight line.

3. The radio wave control plate according to claim 1, wherein the boundary between the first region and the second region is parallel to the direction of the phase gradient of the first region and the second region.

4. A radio wave control board as described in any one of claims 1 to 3, wherein the second change amount is set to the first change amount + 180°, the third change amount is set to the first change amount + 90°, and the fourth change amount is set to the first change amount + 270°.

5. A radio wave control board according to any one of claims 1 to 4, wherein the area of ​​the region in which the first unit structures are arranged is equal to the area of ​​the region in which the second regions are arranged.

6. The radio wave control board according to any one of claims 1 to 5, wherein at least one of the first area and the second area is divided into a plurality of areas.

7. When the predetermined direction is an angle θ0 and k is the wave number of the incident radio wave, the phase change amount of each of the plurality of first unit structures is such that the phase gradient of the first region is k sinθ ０ The phase change amount of each of the plurality of second unit structures is set so that the phase gradient of the second region is closest to k sinθ ０ The radio wave control board according to claim 1 , wherein the value is set to be closest to 8. A radio wave control board as described in any one of claims 1 to 7, wherein the phase change amounts of the plurality of first unit structures and the plurality of second unit structures are set so that the distribution of phase change amounts in the first region and the distribution of phase change amounts in the second region are closest to each other.

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