Frequency selective reflector and communication relay system

Abstract

To provide a frequency selective reflector that controls an area irradiated with a reflected beam that reflects electromagnetic waves in a specific frequency band in a different direction from the direction of normal reflection and that converts spherical waves into plane waves, and a communication relay system using the frequency selective reflector.SOLUTION: A frequency selective reflector 1, which reflects electromagnetic waves in a specific frequency band in a different direction from the direction of normal reflection, has a plurality of regions A0, A11 to Amn and a function of adjusting a reflected beam profile. The frequency selective reflector has a function of broadening the reflected beam across the entire frequency selective reflector by adjusting the reflected beam profile by making the reflection characteristics of electromagnetic waves in each segmented area different from each other, a function of narrowing the reflected beam across the entire frequency selective reflector and a function of converting spherical waves to plane waves across the entire frequency selective reflector.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a frequency selective reflector that reflects electromagnetic waves in a specific frequency band in a direction different from the direction of specular reflection, and a communication relay system using the same. [Background technology]

[0002] As described in Patent Documents 1-2 and Non-Patent Document 1, in mobile communication systems, reflectarray technology is being considered to improve the propagation environment and area. High frequencies used in fifth-generation mobile communication systems (5G) have a strong tendency to travel in a straight line, so eliminating coverage holes, which are areas where radio waves cannot reach, is an important issue.

[0003] A reflectarray is required to reflect electromagnetic waves of a specific frequency incident from a base station in a predetermined direction in a desired direction. In such a reflectarray, for example, a plurality of reflecting elements are arranged. A technology has been developed that changes the size and shape of the reflecting elements to change the resonant frequency of each reflecting element, thereby controlling the reflection phase of the electromagnetic wave, and thereby controlling the incident direction and reflection direction of the electromagnetic wave. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5371633 [Patent Document 2] Patent No. 5162677 [Non-patent literature]

[0005] [Non-Patent Document 1] Mayumi Yoshino et al., "Improvement of received power in non-line-of-sight environments in L-shaped corridors using meta-surface reflectors," IEICE Technical Report A·P2020-5 (April 2020) Summary of the Invention [Problem to be solved by the invention]

[0006] The size of the reflectarray is appropriately set taking into consideration the positional relationship between the base station, the reflectarray, and the coverage hole, the frequency of the electromagnetic waves, the required signal strength, etc. In the case of high frequencies used in 5G, reflectarrays larger than several tens of centimeters square are generally used. In such reflectarrays, as the size increases, the gain increases in principle, and the reflected beam by the reflectarray becomes sharper. However, since the beam width of the reflected wave by the reflectarray becomes narrower, the area irradiated by the reflected beam by the reflectarray becomes narrower. It is desired to expand the area irradiated by the reflected beam by the reflectarray, even if the gain is somewhat reduced within a range where the required signal strength can be secured.

[0007] On the other hand, when it is desired to concentrate electromagnetic waves at a specific location, it is desirable to narrow the beam width of the waves reflected by the reflectarray, i.e., to narrow the area irradiated by the reflected beam from the reflectarray.

[0008] When the reflectarray is located far enough away from the base station, the incident wave from the base station can be considered as a plane wave. On the other hand, when the reflectarray is located close to the base station, the incident wave from the base station must be treated as a spherical wave. However, the design of conventional reflectarrays is premised on the incident wave being a plane wave. Therefore, when the base station and the reflectarray are located close to each other, there is a problem that the reflection characteristics as designed cannot be obtained.

[0009] The present disclosure has been made in consideration of the above-mentioned circumstances, and has as its main object to provide a frequency selective reflector that is capable of controlling an area onto which a reflected beam is irradiated, for example by widening or narrowing the area onto which the reflected beam is irradiated, and is also capable of converting a spherical wave into a plane wave. [Means for solving the problem]

[0010] One embodiment of the present disclosure provides a frequency selective reflector that reflects electromagnetic waves of a specific frequency band in a direction other than the direct reflection direction, the frequency selective reflector having multiple regions and the ability to adjust the reflected beam profile.

[0011] Another embodiment of the present disclosure provides a communication relay system for relaying communications between a base station and a user terminal, the communication relay system having a plurality of directional control devices for changing the direction of propagation of electromagnetic waves of a specific frequency band, each of the plurality of directional control devices being positioned on a propagation path of the electromagnetic waves from the base station, and the communication relay system having one or more of the above-mentioned frequency selective reflectors as the directional control devices. Effect of the Invention

[0012] The frequency selective reflector of the present disclosure has the advantage that it is possible to control the area onto which the reflected beam is irradiated, and also possible to convert a spherical wave into a plane wave. [Brief description of the drawings]

[0013] [Figure 1] 1 is a schematic plan view illustrating a frequency selective reflector of the present disclosure. [Diagram 2] 1 is a schematic plan view illustrating the reflection characteristics of a main region and each sub-region in a frequency selective reflector of the present disclosure. FIG. [Diagram 3] 1 is a schematic plan view illustrating the reflection characteristics of a main region and each sub-region in a frequency selective reflector of the present disclosure. FIG. [Figure 4] 1 is a schematic plan view illustrating the reflection characteristics of a main region and each sub-region in a frequency selective reflector of the present disclosure. FIG. [Diagram 5] 1 is a schematic plan view illustrating the reflection characteristics of a main region and each sub-region in a frequency selective reflector of the present disclosure. FIG. [Figure 6] FIG. 2 is a schematic diagram illustrating a coordinate system of a frequency selective reflector according to the present disclosure. [Figure 7]1 is a schematic plan view illustrating the reflection characteristics of a main region and each sub-region in a frequency selective reflector of the present disclosure. FIG. [Figure 8] 1A and 1B are schematic plan and perspective views illustrating the reflection characteristics of a main region and each sub-region in a frequency selective reflector of the present disclosure. [Figure 9] 1 is a schematic plan view illustrating a frequency selective reflector of the present disclosure. [Figure 10] 1 is a schematic plan view illustrating the reflection characteristics of a main region and each sub-region in a frequency selective reflector of the present disclosure. FIG. [Figure 11] 1 is a schematic plan view illustrating the reflection characteristics of a main region and each sub-region in a frequency selective reflector of the present disclosure. FIG. [Figure 12] 4 is a schematic diagram illustrating an angle between reflection direction vectors of electromagnetic waves between adjacent divided regions in a frequency selective reflector according to the present disclosure. FIG. [Figure 13] 1 is a graph illustrating a reflected beam profile by a frequency selective reflector of the present disclosure. [Figure 14] 1A and 1B are schematic cross-sectional and plan views illustrating a frequency selective reflector of the present disclosure. [Figure 15] 1 is a schematic diagram for explaining how to obtain a reflection direction vector of an electromagnetic wave in a divided region in a frequency selective reflector of the present disclosure. FIG. [Figure 16] 1A to 1C are schematic plan views and cross-sectional views illustrating a frequency selective reflector of the present disclosure, and a schematic diagram for explaining the relative reflection phase of an electromagnetic wave in each cell region of a unit structure of a dielectric layer in the frequency selective reflector of the present disclosure. [Figure 17] 1 is a schematic diagram for explaining how to obtain a reflection direction vector of an electromagnetic wave in a divided region in a frequency selective reflector of the present disclosure. FIG. [Figure 18] 1A and 1B are schematic perspective and plan views illustrating unit structures of a dielectric layer in a frequency selective reflector according to the present disclosure. [Figure 19] 2 is a schematic plan view illustrating a unit structure of a dielectric layer in the frequency selective reflector of the present disclosure. FIG. [Figure 20] 1 is a schematic cross-sectional view illustrating a frequency selective reflector according to the present disclosure. [Figure 21] 1A to 1C are schematic cross-sectional views illustrating a frequency selective reflector of the present disclosure, and schematic views for explaining the relative reflection phase of an electromagnetic wave in each cell region of a unit structure of a dielectric layer in the frequency selective reflector of the present disclosure. [Figure 22] 1A to 1C are schematic cross-sectional views illustrating a frequency selective reflector of the present disclosure, and schematic views for explaining the relative reflection phase of an electromagnetic wave in each cell region of a unit structure of a dielectric layer in the frequency selective reflector of the present disclosure. [Figure 23] 2A to 2C are schematic diagrams illustrating the configuration of unit structures of a dielectric layer in a frequency selective reflector according to the present disclosure. [Figure 24] 1 is a schematic cross-sectional view illustrating a frequency selective reflector according to the present disclosure. [Diagram 25] 1A to 1C are schematic plan views illustrating a reflecting member in a frequency selective reflector of the present disclosure and schematic cross-sectional views illustrating a frequency selective reflector of the present disclosure. [Figure 26] 1A to 1C are schematic plan views illustrating a reflecting member in a frequency selective reflector of the present disclosure and schematic cross-sectional views illustrating a frequency selective reflector of the present disclosure. [Figure 27] 1 is a schematic cross-sectional view illustrating a frequency selective reflector according to the present disclosure. [Figure 28] 3 is a schematic diagram illustrating the solid angle of a beam reflected by a frequency selective reflector according to the present disclosure. FIG. [Figure 29] 3 is a schematic plan view illustrating the reflection characteristics of each divided region in the frequency selective reflector of the present disclosure. FIG. [Diagram 30] 1 is a schematic plan view illustrating a frequency selective reflector of the present disclosure. [Diagram 31] FIG. 11 is a schematic plan view illustrating a cell region in a frequency selective reflector of the present disclosure, and is a schematic view illustrating a cell region in a frequency selective reflector of Example 4. [Diagram 32] 1 is a schematic plan view illustrating a cell region in a frequency selective reflector of the present disclosure. [Diagram 33] FIG. 1 is a schematic diagram illustrating an arrangement of a conventional reflect array. [Diagram 34] FIG. 23 is a schematic diagram illustrating the arrangement of a frequency selective reflector in Example 10. [Diagram 35] 1 is a schematic diagram illustrating the arrangement of a direction control device in a communication relay system of the present disclosure. [Diagram 36] 1 is a schematic diagram illustrating the arrangement of a direction control device in a communication relay system of the present disclosure. [Figure 37] 1 is a graph showing a simulation result of Example 1. [Figure 38] 13 is a graph showing a simulation result of Example 2. [Figure 39] 13 is a graph showing a simulation result of Comparative Example 1. [Diagram 40] 13 is a graph showing a simulation result of Example 3. [Diagram 41] 1 is a graph showing a simulation result of Reference Example 1. [Diagram 42] 13 is a schematic perspective view showing a simulation model of Reference Example 2 and a graph showing the simulation results. [Diagram 43] 13 is a schematic perspective view showing a simulation model of Reference Example 3 and a graph showing the simulation results. [Diagram 44] FIG. 2 is a schematic diagram illustrating a transmission line equivalent circuit. [Diagram 45] 11 is a schematic diagram illustrating a cell region in the frequency selective reflector of Example 5. FIG. [Diagram 46] 13 is a schematic diagram illustrating a cell region in a frequency selective reflector of Example 6. FIG. [Figure 47] FIG. 13 is a schematic diagram illustrating a cell region in the frequency selective reflector of Example 7. [Figure 48] FIG. 13 is a schematic diagram illustrating a cell region in the frequency selective reflector of Example 8. [Figure 49] 13 is a schematic diagram illustrating a cell region in the frequency selective reflector of Example 9. FIG. [Figure 50] FIG. 23 is a schematic diagram showing the reflection characteristics of the frequency selective reflector of Example 10. [Figure 51] FIG. 23 is a schematic diagram showing the reflection characteristics of the frequency selective reflector of Example 10. [Figure 52] 13 is a graph showing the download speed ratio at each measurement position for Example 10 and Reference Example 6. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The embodiments of the present disclosure will be described with reference to the drawings. However, the present disclosure can be implemented in many different forms, and should not be interpreted as being limited to the contents of the embodiments. In addition, the drawings may be schematic in terms of the width, thickness, shape, etc. of each part compared to the actual form in order to make the explanation clearer, but these are merely examples and do not limit the interpretation of the present disclosure. In this specification and each figure, elements similar to those described above with respect to the previous figures may be given the same reference numerals, and detailed explanations may be omitted as appropriate.

[0015] In this specification, when expressing a mode in which another member is disposed on a certain member, the term "above" or "below" includes both cases in which another member is disposed directly above or below a certain member so as to be in contact with the certain member, and cases in which another member is disposed above or below a certain member through another member, unless otherwise specified. When expressing a mode in which another member is disposed above a certain member, the term "above" or "below" includes both cases in which another member is disposed directly above or below a certain member so as to be in contact with the certain member, and cases in which another member is disposed above or below a certain member through another member, unless otherwise specified. In addition, in this specification, when expressing a mode in which another member is disposed on a surface of a certain member, the term "on a surface" includes both cases in which another member is disposed directly above or below a certain member so as to be in contact with the certain member, and cases in which another member is disposed above or below a certain member through another member, unless otherwise specified.

[0016] A frequency selective reflector and a communication relay system using the same according to the present disclosure will be described.

[0017] A. Frequency selective reflector The frequency selective reflector in the present disclosure is a frequency selective reflector that reflects electromagnetic waves in a specific frequency band in a direction different from the specular reflection direction, has a plurality of regions, and has the function of adjusting the reflected beam profile.

[0018] The frequency selective reflector of the present disclosure has a function of adjusting the reflected beam profile, and therefore can widen or narrow the beam of the reflected wave by the entire frequency selective reflector. Furthermore, it is also possible to convert a spherical wave into a plane wave and reflect it by the entire frequency selective reflector.

[0019] The frequency selective reflector of the present disclosure has a plurality of regions, and reflects electromagnetic waves of a specific frequency band in a direction different from the regular reflection direction. Therefore, the reflected beam profile by the entire frequency selective reflector is formed by combining the reflected beams by each region. For example, the incident angle and the reflection angle in each region are controlled according to the position on the frequency selective reflector. In other words, the reflection characteristics such as the incident direction vector and the reflection direction vector in each region are controlled according to the position on the frequency selective reflector. This allows the reflected beam profile to be adjusted. In addition, when the number of regions is increased and the size of each region is reduced to the region where the reflection phase of the electromagnetic wave can be set, that is, the size of the cell region, for example, the reflection phase in each region is controlled according to the position on the frequency selective reflector. This also allows the reflected beam profile to be adjusted.

[0020] Also, when the incident wave is a plane wave, the incident direction vector of the electromagnetic wave is the same throughout the frequency selective reflector. On the other hand, when the incident wave is a spherical wave, the incident direction vector of the electromagnetic wave differs depending on the position on the frequency selective reflector. In this way, even when the incident angle of the electromagnetic wave, i.e., the incident direction vector, is the same throughout the frequency selective reflector, and even when the incident angle of the electromagnetic wave, i.e., the incident direction vector, differs depending on the position on the frequency selective reflector, different incident angles and reflection angles can be set for each region. In other words, reflection characteristics such as different incident direction vectors and reflection direction vectors can be set for each region. Also, when the size of each region is reduced to the size of the cell region, different reflection phases can be set for each region. Therefore, whether the incident wave is a plane wave or a spherical wave, the reflection beam profile can be adjusted.

[0021] Here, the "reflected beam profile" in the "function of adjusting the reflected beam profile" refers to the shape of the main lobe (main beam) in the reflected beam profile, and more specifically, the angular distribution and intensity distribution of the main lobe.

[0022] In addition, the function of adjusting the reflected beam profile includes, for example, a function of widening the reflected beam over the entire frequency selective reflector, a function of narrowing the reflected beam over the entire frequency selective reflector, and a function of converting a spherical wave into a plane wave over the entire frequency selective reflector. When widening the reflected beam and when narrowing the reflected beam, the incident wave may be a plane wave or a spherical wave. When widening the reflected beam, the reflected beam may be widened in the horizontal direction, the reflected beam may be widened in the vertical direction, or the reflected beam may be widened in both the horizontal and vertical directions. Similarly, when narrowing the reflected beam, the reflected beam may be narrowed in the horizontal direction, the reflected beam may be narrowed in the vertical direction, or the reflected beam may be narrowed in both the horizontal and vertical directions. When widening the reflected beam, the reflected beam may be widened in the horizontal direction and narrowed in the vertical direction, or the reflected beam may be narrowed in the horizontal direction and widened in the vertical direction.

[0023] The frequency selective reflector of the present disclosure may be, for example, a frequency selective reflector in which the entire surface of the frequency selective reflector is divided into a plurality of divided regions, and the reflection characteristics of the electromagnetic wave in each divided region are different from each other. In the frequency selective reflector, the reflection beam profile can be adjusted by making the reflection characteristics of the electromagnetic wave in each divided region different from each other. The reflection characteristics are at least one of the incident direction vector and the reflection direction vector. The different reflection characteristics include the cases where the incident direction vector is different, the reflection direction vector is different, and the incident direction vector and the reflection direction vector are different. In these cases, the multiple divided regions correspond to the multiple regions of the frequency selective reflector of the present disclosure.

[0024] When the incident wave is a plane wave, the incident direction vector of the electromagnetic wave is the same throughout the frequency selective reflector. For example, when an incident plane wave is reflected as a plane wave and the reflected beam is expanded throughout the frequency selective reflector, the reflection direction vector of the electromagnetic wave in each divided area may be set to expand outward with a reflection direction vector of a certain electromagnetic wave as the center. Also, for example, when an incident plane wave is reflected as a plane wave and the reflected beam is narrowed throughout the frequency selective reflector, the reflection direction vector of the electromagnetic wave in each divided area may be set to converge inward with a reflection direction vector of a certain electromagnetic wave as the center.

[0025] On the other hand, when the incident wave is a spherical wave, the incident direction vector of the electromagnetic wave differs depending on the position on the frequency selective reflector. For example, when an incident spherical wave is reflected as a spherical wave and the reflected beam is expanded by the entire frequency selective reflector, the reflection direction vector of the electromagnetic wave in each divided area may be set to expand outward from the reflection direction vector of a certain electromagnetic wave as the center while correcting the difference in the incident direction vector in each divided area. Also, for example, when an incident spherical wave is reflected as a spherical wave and the reflected beam is narrowed by the entire frequency selective reflector, the reflection direction vector of the electromagnetic wave in each divided area may be set to converge inward from the reflection direction vector of a certain electromagnetic wave as the center while correcting the difference in the incident direction vector in each divided area.

[0026] Furthermore, for example, when an incident spherical wave is reflected as a plane wave, the reflection direction vector of the electromagnetic wave in each divided region may be set to be the same while correcting the difference in the incident direction vector in each divided region.

[0027] In a frequency selective reflector in which the entire surface is divided into a plurality of divided regions and the electromagnetic wave reflection characteristics of each divided region are different from one another, the configuration of the divided regions and the frequency selective reflector is the same as the divided regions and configurations of the frequency selective reflectors of the first to fourth embodiments described below.

[0028] Further, the frequency selective reflector of the present disclosure may be, for example, a frequency selective reflector in which the size of the region is reduced to the size of the cell region, and a plurality of cell regions having different reflection phases of electromagnetic waves are repeatedly arranged. In this case, the plurality of cell regions correspond to the plurality of regions of the frequency selective reflector of the present disclosure.

[0029] In a frequency selective reflector, for example, when an incident plane wave is reflected as a plane wave and the reflected beam is expanded by the entire frequency selective reflector, the reflection phase of the electromagnetic wave in each cell region may be set so that the reflected beam is expanded by the entire frequency selective reflector. Also, for example, when an incident plane wave is reflected as a plane wave and the reflected beam is narrowed by the entire frequency selective reflector, the reflection phase of the electromagnetic wave in each cell region may be set so that the reflected beam is narrowed by the entire frequency selective reflector.

[0030] For example, when an incident spherical wave is reflected as a spherical wave and the reflected beam is widened by the entire frequency selective reflector, the reflection phase of the electromagnetic wave in each cell region may be set so that the reflected beam is widened by the entire frequency selective reflector while correcting the difference in the incident direction vector in each cell region. For example, when an incident spherical wave is reflected as a spherical wave and the reflected beam is narrowed by the entire frequency selective reflector, the reflection phase of the electromagnetic wave in each cell region may be set so that the reflected beam is narrowed by the entire frequency selective reflector while correcting the difference in the incident direction vector in each cell region.

[0031] Furthermore, for example, when an incident spherical wave is reflected as a plane wave, the difference in the incident direction vector in each cell region can be corrected, and the reflection phase of the electromagnetic wave in each cell region can be set so that the reflection direction vector of the electromagnetic wave is the same across the entire frequency selective reflector.

[0032] In a frequency selective reflector in which multiple cell areas with different reflection phases of electromagnetic waves are repeatedly arranged, the configuration of the cell areas and the frequency selective reflector is the same as the cell areas and configuration of the frequency selective reflector of the fifth embodiment described below.

[0033] The frequency selective reflector in the present disclosure has five preferred embodiments. In the present disclosure, when the reflected beam is broadened by the entire frequency selective reflector, the frequency selective reflectors in the first, second and fifth embodiments are preferred. In the present disclosure, when the reflected beam is narrowed by the entire frequency selective reflector, the frequency selective reflectors in the third, fourth and fifth embodiments are preferred. In the present disclosure, when the incident wave is not a plane wave or a substantially plane wave, the frequency selective reflector in the fifth embodiment is preferred.

[0034] In the following description, the in-plane reflection phase distribution design and the reflection direction vector in the divided regions and unit structures determined by the design will be described assuming a case where the incident wave incident on the frequency selective reflector from the front direction is reflected in a direction other than the regular reflection direction. Here, for the reflection phase distribution design in the case of incidence from the front direction, the sum of the reflection phase distribution that reflects from the assumed incident direction to the front direction and the reflection phase distribution that reflects from the front direction to the assumed reflection direction may be taken. In this case, the reflection phase distribution that reflects from the assumed incident direction to the front direction is, in principle, the same as the reflection phase distribution that reflects from the front direction to the assumed incident direction. Therefore, in practice, the sum of the reflection phase distribution from the front direction to the assumed incident direction and the reflection phase distribution from the front direction to the assumed reflection direction may be considered. For any reflection phase distribution design, the design method for incidence from the front direction may be applied.

[0035] Each embodiment will be described below.

[0036] I. First embodiment The frequency selective reflector of this embodiment is a frequency selective reflector that reflects electromagnetic waves of a specific frequency band in a direction different from the direct reflection direction, and the entire surface of the frequency selective reflector is divided into a plurality of divided regions, and the plurality of divided regions have a main region which is a divided region located at the center of the frequency selective reflector, and a plurality of sub-regions which are divided regions other than the main region, and the plurality of sub-regions are arranged around the main region, and the reflection direction vectors of the electromagnetic waves in each of the divided regions are different from each other, and the reflection direction vectors of the electromagnetic waves in each of the sub-regions are set to spread outward from the reflection direction vector of the electromagnetic wave in the main region as a center.

[0037] Fig. 1 is a schematic plan view showing an example of a frequency selective reflector of this embodiment. As shown in Fig. 1, the entire surface of the frequency selective reflector 1 is divided into a plurality of divided regions, and the plurality of divided regions are a main region A0 which is a divided region located at the center of the frequency selective reflector 1, and a plurality of sub-regions A1, which are divided regions other than the main region A0. 11 ~A 33and a plurality of sub-areas A 11 ~A 33 In the example shown in FIG. 1, the frequency selective reflector 1 is divided into nine divided regions, one main region A0 and eight sub-regions A1, A2, A3, A4, A5, A6, A7, A8, A9, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, A23, A24, A25, A26, A27, A28, A29, A30, A31, A32, A33, A34, A35, A36, A37, A38, A39, A41, A42, A43, A44, A45, A46, A47, A48, A49, A51, A52, A53, A54, A55, A56, A57, A58, A59, A60, A 11 ~A 33 The main area A0 is surrounded by eight sub-areas A1 and A2. 11 ~A 33 are placed.

[0038] 2 to 5 show an example of the reflection characteristics of the main region and each sub-region in the frequency selective reflector shown in Fig. 1. Here, as shown in Fig. 6, for example, when the frequency selective reflector 1 is set vertically on the ground (XZ plane) and viewed from the electromagnetic wave reflecting side, the left corner is the origin, the horizontal direction is the x-axis, the vertical direction is the y-axis, and the normal direction to the reflecting side is the z-axis, the electromagnetic wave reflection direction vector d r The polar angle is defined as θ and the azimuth angle as φ.

[0039] The reflected direction vector of the electromagnetic wave in the main area A0 is from the main area A0 to the subarea A 23 When the reflector is tilted toward the φ=0° direction, the polar angle of the reflected electromagnetic wave vector in the main area A0 is θ r , azimuth angle is φ r Then, each sub-area A 11 ~A 33 The polar angle and azimuth angle of the reflected electromagnetic wave vector in the sub-area A are 11 Then (θ r -α, φ r +β), subregion A 21 Then (θ r -α, φ r ), sub-area A 31 Then (θ r -α, φ r -β), subregion A 12 Then (θ r , φ r +β), subregion A 32 Then (θ r φ r -β), subregion A 13 Then (θ r +α, φr +β), subregion A 23 Then (θ r +α, φ r ), sub-area A 33 Then (θ r +α, φ r -β), where α and β are positive numbers.

[0040] The amount of displacement of the polar angle and azimuth angle of the reflection direction vector of the electromagnetic wave in each of these sub-areas depends on the direction in which the reflection direction vector of the electromagnetic wave in the main area is inclined with respect to the surface of the frequency selective reflector. 21 4 shows an example in which the reflection direction vector of the electromagnetic wave in the main region A0 is inclined toward the sub-region A 12 5 shows an example in which the reflection direction vector of the electromagnetic wave in the main region A0 is inclined toward the sub-region A 32 This is an example of the case where the lens is tilted to the side (φ=270°).

[0041] The values ​​and signs of α and β are merely guidelines when the reflection direction vector of the electromagnetic wave is expressed in polar coordinates. The values ​​and signs of α and β vary depending on the settings of the reflection direction vector of the electromagnetic wave in the main region and the spread of the reflection direction vector of the electromagnetic wave over the entire frequency selective reflector.

[0042] The reflection direction vector of the electromagnetic wave in each sub-region is set to spread outward from the reflection direction vector of the electromagnetic wave in the main region. As described later, it is preferable that the angle θds between the reflection direction vectors of the electromagnetic wave in adjacent divided regions is set to be within a predetermined range.

[0043] Fig. 7 shows a concrete example of the reflection characteristics of the main region and each sub-region in the frequency selective reflector shown in Fig. 1 and Fig. 2. Fig. 7 shows the polar angle θ of the reflection direction vector of the electromagnetic wave in the main region A0 in Fig. 2.r 25°, azimuth angle φ r This is a specific example where is 20°, α is 4°, and β is 4°.

[0044] In this way, each sub-area A 11 ~A 33 The reflection direction vector of the electromagnetic wave in the main region A0 is subtly different from the reflection direction vector of the electromagnetic wave in the main region A1, and the two are different from each other.

[0045] 8(a) to 8(c) show examples of the reflection characteristics of the main region and each sub-region in the frequency selective reflector shown in FIG. 1 and FIG. 2. As shown in FIG. 8(a), the frequency selective reflector 1 reflects electromagnetic waves in a specific frequency band (incident wave W i ) in a direction different from the regular reflection (specular reflection) direction. For example, in the main area A0, the incident wave W i The incidence angle θ i and the reflected wave W r Reflection angle θ r 2, 7, and 8(b), the azimuth angle φ of the reflection vector of the electromagnetic wave is different from that of the sub-area A 32 In the sub-area A, the azimuth angle φ is smaller than that of the main area A0. 12 In the sub-area A, the azimuth angle φ is larger than that of the main area A0. 32 , Main area A0, Sub area A 12 In the order of , the azimuth angle φ of the reflected direction vector of the electromagnetic wave gradually increases. Similarly, in the sub-area A 31 , A 21 , A 11 In the order of, the azimuth angle φ of the reflected direction vector of the electromagnetic wave gradually increases, and the sub-area A 33 , A 23 , A 13 In the order of , the azimuth angle φ of the reflection direction vector of the electromagnetic wave gradually increases. On the other hand, as shown in Figs. 2, 7, and 8(c), the polar angle θ of the reflection direction vector of the electromagnetic wave increases in the sub-area A. 21 In the main area A0, the polar angle θ is small, and the sub-area A 23 In the main area A0, the polar angle θ is large, and the sub-area A 21 , Main area A0, Sub area A 23In the order of , the polar angle θ of the reflected direction vector of the electromagnetic wave gradually increases. Similarly, in sub-area A 11 , A 12 , A 13 In the order of, the polar angle θ of the reflected direction vector of the electromagnetic wave gradually increases, and the sub-area A 31 , A 32 , A 33 In this manner, the polar angle θ of the reflection direction vector of the electromagnetic wave gradually increases along the x-axis direction, and the azimuth angle φ of the reflection direction vector of the electromagnetic wave gradually increases along the y-axis direction. 11 ~A 33 The reflection direction vector of the electromagnetic wave at each sub-area A is set. 11 ~A 33 The reflection direction vector of the electromagnetic wave in the main region A0 can be set to spread outward with the reflection direction vector of the electromagnetic wave in the main region A0 as the center.

[0046] In such a case, a given incidence angle θ i The incident electromagnetic wave (incident wave W i ) for the main area A0 and each sub-area A 11 ~A 33 By reflecting the electromagnetic wave according to the reflection characteristics (polar angle θ, azimuth angle φ) of the main area A0, it is possible to reflect the electromagnetic wave with a spread centered on the reflection direction vector of the main area A0. 11 ~A 33 As the reflected beams from the frequency selective reflector overlap, one main lobe (main beam) is formed in the reflected beam profile from the entire frequency selective reflector 1, and it is possible to widen the beam width of the reflected wave from the entire frequency selective reflector 1. This makes it possible to widen the area irradiated with the reflected beam from the frequency selective reflector.

[0047] In addition, in the case where a frequency selective reflector has only a main region, for example, as in the conventional case, if the size of the frequency selective reflector is increased, the gain increases in principle and the reflected beam by the frequency selective reflector becomes sharper. In this case, the beam width of the reflected wave by the frequency selective reflector becomes narrower, so the area irradiated by the reflected beam by the frequency selective reflector becomes narrower.

[0048] Here, in the case where a frequency selective reflector does not have a divided region, i.e., for example, has only a main region, as in the conventional case, and the planar shape of the frequency selective reflector is, for example, circular, the half-width FWHM in the reflected beam profile by the frequency selective reflector is generally expressed by the following formula (2). FWHM[rad]=λ / (0.8×D)~λ / (0.6×D) (2) In the above formula (2), λ is the wavelength of the electromagnetic wave, and D is the diameter of the frequency selective reflector. In other words, if you try to create a frequency selective reflector of a size sufficient to obtain the received power, the full width at half maximum (FWHM) of the reflected beam profile will be narrow, and the area irradiated by the reflected beam by the frequency selective reflector will be narrow.

[0049] In contrast, in this embodiment, the frequency selective reflector is divided into a main region and a plurality of sub-regions, and the size of the main region and each sub-region is small, so that the gain is somewhat reduced, but the beam width of the reflected wave by the main region and each sub-region is widened. Furthermore, the reflection direction vectors of the electromagnetic wave in the main region and each sub-region are different from each other, and the reflection direction vectors of the electromagnetic wave in each sub-region are set to spread outward from the reflection direction vector of the electromagnetic wave in the main region as the center, so that the reflected beams from the main region and each sub-region overlap, and the beam width of the reflected wave by the entire frequency selective reflector can be widened. Therefore, it is possible to widen the area where the reflected beam from the frequency selective reflector is irradiated. This makes it possible to realize a reflected beam profile as if it were a convex mirror.

[0050] Each component of the frequency selective reflector of this embodiment will be described below.

[0051] 1. Split area (main area and sub area) The entire surface of the frequency selective reflector in this embodiment is divided into a plurality of divided regions, each of which has a main region which is a divided region located at the center of the frequency selective reflector, and a plurality of sub-regions which are divided regions other than the main region, and the plurality of sub-regions are arranged around the main region.

[0052] The sub-regions are arranged around the main region, which includes not only the case where the sub-regions are arranged around the entire periphery of the main region, but also the case where the sub-regions are arranged around only a part of the periphery of the main region.

[0053] The sub-regions may be arranged around the main region, and the arrangement of the sub-regions may be appropriately selected depending on the reflection characteristics of the entire frequency selective reflector, the reflection characteristics of the main region and each of the sub-regions, the planar shapes of the main region and each of the sub-regions, etc.

[0054] The sub-regions are preferably arranged symmetrically around the main region, and more preferably arranged symmetrically around the entire periphery of the main region. By arranging the sub-regions symmetrically around the main region, it is possible to arrange a large number of sub-regions whose electromagnetic wave reflection direction vectors are slightly different from those of the main region. This increases the degree of freedom in design and makes it possible to accommodate various reflection beam profiles.

[0055] For example, as shown in FIG. 8(b), two sub-areas A1 and A2 are symmetrically arranged around the main area A0. 12 , A 32 In the case where sub-area A 32 , Main area A0, Sub area A 12When the azimuth angle φ of the reflection direction vector of the electromagnetic wave gradually increases in the order of 1 to 4, the reflected beam by the entire frequency selective reflector can be spread in the horizontal direction.

[0056] Also, for example, as shown in FIG. 8(c), two sub-areas A1 and A2 are formed symmetrically around the main area A0. 21 , A 23 In the case where sub-area A 21 , Main area A0, Sub area A 23 When the polar angle θ of the reflection direction vector of the electromagnetic wave is gradually increased in the order of θ, the reflected beam by the entire frequency selective reflector can be expanded in the vertical direction.

[0057] Also, for example, in Figs. 1, 2, 7, and 9(a) to (f), a plurality of sub-areas are arranged symmetrically with respect to the main area A0 all around the main area A0.

[0058] Examples of the shape of each divided region in a plan view include a rectangle, a parallelogram, a rhombus, a trapezoid, a triangle, a hexagon, a concentric circle, etc. In the case of these shapes in a plan view, the divided regions can be arranged without gaps.

[0059] For example, as shown in FIG. 1, FIG. 2, and FIG. 7, each divided region, i.e., main region A0 and each sub-region A 11 ~A 33 When the planar shape of the main region A0 is rectangular, a plurality of sub-regions A1 are arranged symmetrically around the main region A0. 11 ~A 33 can be placed.

[0060] Also, as shown in FIG. 9(a), for example, each divided region, that is, the main region A0 and each sub-region A 11 ~A 52 When the planar shape of the main region A0 is a hexagonal shape, a plurality of sub-regions A1 are arranged symmetrically around the main region A0. 12 ~A 52 can be placed.

[0061] Also, as shown in FIG. 9B, for example, each divided region, that is, the main region A0 and each sub-region A 12 ~A 23 When the planar shape of the main region A0 is a triangle, a plurality of sub-regions A1 are arranged symmetrically around the main region A0. 12 ~A 23 can be placed.

[0062] Also, for example, as shown in FIG. 9C, each divided region, that is, the main region A0 and each sub-region A 11 ~A 42 When the planar shape of the main region A0 is concentric, a plurality of sub-regions A1 are arranged symmetrically around the main region A0. 11 ~A 42 For example, as shown in FIG. 9(d), each divided area, that is, the main area A0 and each sub-area A 11 ~A 22 When the planar shape of the main region A0 is concentric, a plurality of sub-regions A1 are arranged symmetrically around the main region A0. 11 ~A 22 can be placed.

[0063] The planar shape of the main region and the planar shape of each sub-region may be the same or different. For example, in Figures 1, 2, 7, 9(a) and 9(b), the planar shape of the main region A0 and the planar shape of each sub-region are the same. On the other hand, for example, in Figures 9(c) to (f), the planar shape of the main region A0 and the planar shape of each sub-region are different.

[0064] The planar shapes of the sub-regions may be the same or different. For example, the planar shapes of the sub-regions are the same in Figures 1, 2, 7, 9(a), 9(b), and 9(e). On the other hand, the planar shapes of the sub-regions are different in Figures 9(c), (d), and (f).

[0065] The number of main regions is 1. The main region is a divided region located at the center of the frequency selective reflector, and is usually disposed at the center of the frequency selective reflector.

[0066] The number of sub-regions is multiple and is appropriately selected according to the reflection characteristics of the entire frequency selective reflector, the reflection characteristics of the main region and each sub-region, the arrangement of the main region and each sub-region, the planar shape of the main region and each sub-region, the size of the main region and each sub-region, etc. When the size of the entire frequency selective reflector is constant, the larger the number of sub-regions, i.e., the larger the number of divided regions, the smaller the size of the sub-regions. When the size of the sub-regions is reduced, the disturbance of the reflected beam profile caused by the entire frequency selective reflector is suppressed, and the side lobes in the reflected beam profile tend to be lower. In this case, a broad reflected beam can be stably obtained.

[0067] For example, as shown in FIG. 10, a main area A0 and each sub-area A 11 ~A mn The planar shape of each sub-area A is rectangular, with the main area A0 at the center. 11 ~A mn In the case where the frequency selective reflector 1 is arranged in m rows and n columns, if the size of the entire frequency selective reflector 1 is constant, the larger m and n are, i.e., the sub-region A 11 ~A mn The larger the number of sub-areas, the smaller the size of the sub-areas, and as described above, it is easier to stably obtain a broad reflected beam. 11 ~A 33 The planar shape of each sub-area A is rectangular, with the main area A0 at the center. 11 ~A 33 In FIG. 11, the main area A0 and each sub-area A 11 ~A 99 The planar shape of each sub-area A is rectangular, with the main area A0 at the center. 11 ~A 99are arranged in 9 rows and 9 columns. When the sizes of the frequency selective reflectors 1 shown in Fig. 7 and Fig. 11 are the same, the frequency selective reflector 1 shown in Fig. 11 has a larger number of sub-regions and smaller sizes of the sub-regions, and as described above, it is easier to stably obtain a broad reflected beam.

[0068] In this embodiment, the reflection direction vectors of the electromagnetic waves in the divided regions are different from each other. Specifically, it is sufficient that at least one of the polar angle and the azimuth angle of the reflection direction vector of the electromagnetic waves is different in each divided region.

[0069] In addition, it is preferable that the angle between the reflection direction vectors of the electromagnetic wave between adjacent divided regions is relatively small. In each divided region, the reflection direction vector of the electromagnetic wave changes gradually, which suppresses the disturbance of the reflected beam profile caused by the entire frequency selective reflector, and the side lobes in the reflected beam profile tend to be low. In this case, a broad reflected beam can be stably obtained.

[0070] Adjacent divided regions need only differ in at least one of the polar angle and the azimuth angle of the reflection direction vector of the electromagnetic wave.

[0071] The angle θds between the reflection direction vectors of the electromagnetic waves in adjacent divided regions is, for example, preferably within 15°, more preferably within 5°, even more preferably within 2°, and particularly preferably within 0.5°. On the other hand, the lower limit of the angle θds between the reflection direction vectors of the electromagnetic waves in adjacent divided regions is not particularly limited and is appropriately determined depending on the processing accuracy of the frequency selective reflector.

[0072] In this disclosure, the reflection direction vector of the frequency selective reflector is designed in a polar coordinate system based on the horizontal direction (x-axis), the vertical direction (y-axis), and the normal direction (z-axis) on the assumption that the frequency selective reflector 1 is set up vertically to the ground (XZ plane) as shown in Fig. 6, but the angle θds between the reflection direction vectors r1 and r2 of the electromagnetic waves between the adjacent divided areas A1 and A2 can be derived by simple geometric calculation from the reflection direction in polar coordinates as shown in Fig. 12(a) and (b). A general geometric definition is shown below.

[0073] When v1 = (θ1, φ1, r1) and v2 = (θ2, φ2, r2), the angle (v1, v2) between the two vectors is given by the following equation. (v1, v2)=arccos{(x1×x2+y1×y2+z1×z2) / (r1×r2)} however, x1 = r1 × sin(θ1) × cos(φ1) y1 = r1 × sin(θ1) × sin(φ1) z1 = r1 × cos(θ1) x2 = r2 × sin(θ2) × cos(φ2) y2 = r2 × sin(θ2) × sin(φ2) z2 = r2 × cos(θ2) It is.

[0074] Furthermore, in the plurality of sub-regions, the angles formed by the reflection direction vectors of the electromagnetic waves in adjacent sub-regions may be the same or different, but are usually the same.

[0075] In this embodiment, the reflection direction vector of the electromagnetic wave in each sub-region is set to expand outward from the reflection direction vector of the electromagnetic wave in the main region as the center. By setting the reflection direction vector of the electromagnetic wave in each sub-region in this manner, the beam width of the reflected wave by the entire frequency selective reflector can be expanded.

[0076] On the other hand, if the reflection direction vector of the electromagnetic wave in each sub-region is not set to expand outward from the reflection direction vector of the electromagnetic wave in the main region as the center, but is set randomly, for example, the main lobe (main beam) width does not widen in the reflected beam profile by the entire frequency selective reflector, and the side lobes tend to be high.

[0077] Specifically, the reflection direction vectors of the surrounding sub-regions may be set so that the reflection direction vectors of the electromagnetic waves in each sub-region within the plane of the frequency selective reflector spread outward from the reflection direction vector of the electromagnetic waves in the main region located at the center of the frequency selective reflector. The reflection direction vectors of the electromagnetic waves in each sub-region can be set by the polar angle and azimuth angle of the reflection direction vector of the electromagnetic waves. That is, the polar angle and azimuth angle of the reflection direction vector of the electromagnetic waves in each sub-region are set so that the reflection direction vector of the electromagnetic waves in each sub-region spreads outward from the reflection direction vector of the electromagnetic waves in the main region. At this time, it is preferable that the angle between the reflection direction vectors of the electromagnetic waves in adjacent sub-regions is gradually changed within the range of the angle between the reflection direction vectors of the electromagnetic waves in the above-mentioned adjacent divided regions.

[0078] For example, in the frequency selective reflector 1 shown in Figures 2, 7 and 11, the reflection direction vectors of the electromagnetic wave in the main region and each sub-region are set so that the polar angle θ of the reflection direction vector of the electromagnetic wave gradually increases along the x-axis direction and the azimuth angle φ of the reflection direction vector of the electromagnetic wave gradually increases along the y-axis direction. This allows the reflection direction vector of the electromagnetic wave in each sub-region to be set so as to spread outward from the reflection direction vector of the electromagnetic wave in the main region as the center.

[0079] 2, 7, and 11 show examples in which the polar angle and azimuth angle of the reflection direction vector of the electromagnetic wave monotonically increase along a predetermined direction, but the polar angle and azimuth angle of the reflection direction vector of the electromagnetic wave do not necessarily increase monotonically along a predetermined direction. When setting the polar angle and azimuth angle of the reflection direction vector of the electromagnetic wave in each sub-region so that the reflection direction vector of the electromagnetic wave in each sub-region spreads outward from the reflection direction vector of the electromagnetic wave in the main region as the center, for example, if the range of the polar angle and azimuth angle of the reflection direction vector of the electromagnetic wave in the main region and each sub-region includes the polar angle θ=0° or the azimuth angle φ=0°, the polar angle and azimuth angle of the reflection direction vector of the electromagnetic wave do not monotonically increase along a predetermined direction.

[0080] Furthermore, in a frequency selective reflector, regardless of the planar shape of each divided region, by designing the reflection direction vector of the electromagnetic wave in each sub-region relative to the reflection direction vector of the electromagnetic wave in the main region, like reflection by a convex mirror, the reflection direction vector of the electromagnetic wave in each sub-region can be set to spread outward with the reflection direction vector of the electromagnetic wave in the main region as the center.

[0081] As described above, in the case where a frequency selective reflector does not have a divided region, i.e., for example, has only a main region, as in the conventional case, and the planar shape of the frequency selective reflector is, for example, circular, the half-width FWHM in the reflected beam profile by the frequency selective reflector is generally expressed by the following formula (2). FWHM[rad]=λ / (0.8×D)~λ / (0.6×D) (2) In the above formula (2), λ is the wavelength of the electromagnetic wave, and D is the diameter of the frequency selective reflector.

[0082] In this embodiment, the half-width FWHM of the reflected beam profile by the frequency selective reflector is preferably wider in consideration of practical usability. However, if the half-width FWHM of the reflected beam profile is too wide, the irradiation power per unit area of ​​the frequency selective reflector is reduced, so it is necessary to increase the size of the frequency selective reflector to compensate for the reduced irradiation power. Therefore, in this embodiment, in a graph in which the horizontal axis represents the deviation angle from the reflection direction vector of the electromagnetic wave in the main region and the vertical axis represents the reflection intensity of the electromagnetic wave of the frequency selective reflector, the half-width FWHM of the reflected beam profile is usually preferably within 40°. Of course, when there are few restrictions on the installation location of the frequency selective reflector, the half-width FWHM of the reflected beam profile may be wider than 40°. On the other hand, the lower limit of the half-width FWHM of the reflected beam profile can be, for example, 0.2° or more, and may be 2° or more.

[0083] The half-width FWHM of the reflected beam profile refers to the angle between two points of the electromagnetic wave reflection direction vector, which is 1 / √2 in electric field strength, 1 / 2 in power, and -3 dB in decibels, with respect to the reflection intensity of the electromagnetic wave reflection direction vector in the main region, in the reflected beam profile when cut on a plane including the electromagnetic wave reflection direction vector in the main region, as shown in Figs. 13(a) and (b), for example. The reflected beam profile shown in Fig. 13(a) is an example in which the horizontal axis is the polar angle when cut on an azimuth plane including the electromagnetic wave reflection direction vector in the main region, and the vertical axis is the reflection intensity of the electromagnetic wave. The polar angle θ of the electromagnetic wave reflection direction vector in the main region is 27.5°. The half-width FWHM of the reflected beam profile is the angle between two points, which is 1 / √2 in electric field strength, 1 / 2 in power, and -3 dB in decibels, with respect to the reflection intensity of the electromagnetic wave reflection direction vector (polar angle θ = 27.5°) in the main region, and is 4.5°. The reflected beam profile shown in Fig. 13(b) is a graph in which the horizontal axis represents the deviation angle from the polar angle (θ=27.5°) of the reflection direction vector of the electromagnetic wave in the main region in the reflected beam profile shown in Fig. 13(a). Normally, the reflected beam profile contains waves of varying strength due to its design, but the direction of the peak position when the entire profile is approximated by a curve is the direction of the reflection direction vector of the electromagnetic wave in the main region.

[0084] The size of each divided region is appropriately selected depending on the reflection characteristics of the entire frequency selective reflector, the reflection characteristics of each divided region, the arrangement of each divided region, the planar shape of each divided region, the number of divided regions, etc. The size of each divided region can be, for example, 1 / 3 or less of the size of the frequency selective reflector.

[0085] In a frequency selective reflector, a plurality of cell regions with different reflection phases of electromagnetic waves are usually arranged periodically, i.e., a plurality of unit structures each having a plurality of cell regions with different reflection phases of electromagnetic waves are arranged. The cell regions are regions in the unit structures where the reflection phases of electromagnetic waves are the same. Moreover, the unit structure is a structure for one period, and is a region that indicates a reflection direction vector of one electromagnetic wave.

[0086] In the frequency selective reflector, when the number of divided regions is increased, the size of each divided region can be reduced to the size of the cell region constituting the unit structure, not the size of the unit structure, in terms of design. When the size of each divided region is the size of the cell region, it is practically difficult to identify that the frequency selective reflector is divided into a plurality of divided regions, and the reflection direction vector of the electromagnetic wave is adjusted smoothly over the entire surface of the frequency selective reflector. Even in such a case, it is possible to regard the cell region located at the center of the frequency selective reflector as the main region, and it is usually designed so that the reflection direction vector of the electromagnetic wave in the main region is the center of the reflection direction vector of the electromagnetic wave in the entire frequency selective reflector. In addition, at this time, although the sub-region adjacent to the main region cannot be clearly defined, the entire surface of the frequency selective reflector divided into fine regions can be regarded as a virtual sub-region, and it is preferable that the reflection direction vector of the electromagnetic wave in each divided region is set so that the angle between the reflection direction vectors of the electromagnetic wave between the adjacent divided regions described above is within a predetermined range.

[0087] Therefore, the size of each divided region may be, for example, equal to or larger than the size of the cell region, or equal to or larger than the size of the unit structure.

[0088] If the size of each divided area is as described above, the reflected beam profile can be adjusted, but as the number of divided areas is increased, the disturbance of the reflected beam profile caused by the entire frequency selective reflector is suppressed, and the side lobes in the reflected beam profile tend to become lower. In this case, a broad reflected beam can be stably obtained.

[0089] The size of each divided area may be the same or different. In this embodiment, as described above, the reflected beams from each divided area overlap each other, forming one main lobe (main beam) in the reflected beam profile from the entire frequency selective reflector. However, when the size of each divided area is different, for example, the electromagnetic wave is reflected more strongly from the divided area having a larger size in a narrower solid angle range. Therefore, it is preferable to design the size of each divided area so that there is no gap in the solid angle equivalent to the half width at half maximum (FWHM) of the reflected beam profile formed by overlapping the reflected beams from each divided area.

[0090] 2. Structure of frequency selective reflector The frequency selective reflector of the present disclosure is a member that reflects electromagnetic waves in a specific frequency band in a direction other than the specular reflection direction.

[0091] The frequency selective reflector is not particularly limited as long as it is a member that reflects electromagnetic waves of a specific frequency band in a direction different from the regular reflection direction. For example, it may have a reflecting member that reflects the electromagnetic waves, and the reflecting member may have a reflection phase control function that controls the reflection phase of the electromagnetic waves, or it may have a reflecting member that reflects the electromagnetic waves, and a dielectric layer that is arranged on the electromagnetic wave incident side with respect to the reflecting member, has a concavo-convex structure in which a plurality of unit structures having a thickness distribution that increases in a predetermined direction are arranged, and transmits the electromagnetic waves. In addition, the frequency selective reflector may be a variable frequency selective reflector that controls the reflection phase of the electromagnetic waves by electrical control or mechanical control, thereby making the reflection direction of the electromagnetic waves variable.

[0092] The following description will be divided into a first embodiment in which the frequency selective reflector has a reflecting member that reflects the electromagnetic wave and the reflecting member has a reflection phase control function that controls the reflection phase of the electromagnetic wave, and a second embodiment in which the frequency selective reflector has a reflecting member that reflects the electromagnetic wave and a dielectric layer that is arranged on the incident side of the electromagnetic wave with respect to the reflecting member, has a concavo-convex structure in which a plurality of unit structures having a thickness distribution in which the thickness increases in a predetermined direction are arranged, and transmits the electromagnetic wave.

[0093] (1) First embodiment of frequency selective reflector A first aspect of the frequency selective reflector of this embodiment has a reflecting member that reflects the electromagnetic wave, and this reflecting member has a reflection phase control function that controls the reflection phase of the electromagnetic wave.

[0094] (a) Reflective material The reflecting member in this embodiment is a member that reflects electromagnetic waves in a specific frequency band and has a reflection phase control function of controlling the reflection phase of the electromagnetic waves.

[0095] In this embodiment, the reflecting member usually has a wavelength selection function of reflecting only electromagnetic waves in a specific frequency band. An example of such a reflecting member is a frequency selective plate.

[0096] The frequency selective plate has a frequency selective surface (FSS) that controls reflection and transmission of electromagnetic waves of a specific frequency band, and when it functions as a reflector for electromagnetic waves of a specific frequency band, a plurality of reflecting elements (scattering elements) are arranged in a plane. For example, the frequency selective plate may have a dielectric substrate and a plurality of reflecting elements arranged on the electromagnetic wave incident surface of the dielectric substrate. Figs. 14(a) and (b) are schematic plan views and cross-sectional views showing an example of the frequency selective reflector of this embodiment, and Fig. 14(b) is a cross-sectional view taken along line AA in Fig. 14(a). The frequency selective reflector 1 illustrated in Figs. 14(a) and (b) is an example in which the reflecting member 2 is a frequency selective plate, and the reflecting member 2 has a dielectric substrate 4 and a plurality of reflecting elements 3 arranged on the electromagnetic wave incident surface of the dielectric substrate 4. The frequency selective plate can be appropriately selected from known frequency selective plates.

[0097] In this embodiment, as shown in FIG. 14(a), for example, a plurality of reflecting elements 3 are periodically arranged. If the regions in which the reflecting elements 3 having the same reflection phase of the electromagnetic wave are arranged are respectively cell regions C1 to C4, and the structure of one period is respectively unit structures U, in this embodiment, the reflection direction vectors of the electromagnetic wave are different from each other in each divided region, so that the reflecting member can have a plurality of types of unit structures having different reflection direction vectors of the electromagnetic wave according to the reflection characteristics of each divided region. In this embodiment, each divided region can have at least one unit structure, and may have a plurality of unit structures having the same reflection direction vector of the electromagnetic wave. In addition, when the number of divided regions is increased and a gradual change in the reflection direction vector is designed over the entire surface of the frequency selective reflector, each divided region may have at least one cell region.

[0098] Here, in this embodiment, the reflection direction vector of the electromagnetic wave can be determined as follows. For example, in the reflecting member, a plurality of reflecting elements having different dimensions are periodically arranged, and when a plurality of unit structures having a plurality of reflecting elements having different dimensions are arranged, the dimensions of the reflecting elements repeatedly increase and decrease in a certain direction. In this case, the reflection direction vector can be determined by the length of the unit structure in the direction in which the dimensions of the reflecting elements increase, and the wavelength of the electromagnetic wave. Specifically, first, as illustrated in FIG. 6, a case is assumed in which the frequency selective reflector 1 is vertically set on the ground (xz plane), and a three-dimensional orthogonal coordinate system is assumed based on the horizontal direction (x-axis), the up-down direction (y-axis), and the normal direction (z-axis). This three-dimensional orthogonal coordinate system is a three-dimensional orthogonal coordinate system in which the surface of the frequency selective reflector 1 is the xy plane, and the normal direction of the surface of the frequency selective reflector 1 is the z axis. Next, the direction in which the dimensions of the reflecting elements increase in the xy plane is obtained. For example, in the case of FIG. 14, the direction in which the dimensions of the reflecting element 3 increase in the xy plane is indicated by the direction D11. Next, the length of the unit structure in the direction in which the size of the reflecting element increases on the xy plane is obtained. For example, in the case of FIG. 14, the length of the unit structure U in the direction D11 in which the size of the reflecting element 3 increases on the xy plane is indicated by length L11. Next, in the above three-dimensional orthogonal coordinate system, the wavelength of the electromagnetic wave is taken parallel to the z-axis. Then, a right-angled triangle is created with the right-angled apex being the starting point of the direction in which the size of the reflecting element of the unit structure on the xy plane increases, and the length of the direction in which the size of the reflecting element of the unit structure on the xy plane increases and the wavelength of the electromagnetic wave parallel to the z-axis as adjacent sides. The normal direction of the hypotenuse of this right-angled triangle is the reflection direction vector of the electromagnetic wave when the incident direction of the electromagnetic wave is parallel to the z-axis. 15(a) and 15(b), for example, in the above three-dimensional orthogonal coordinate system, a right-angled triangle RT is created with the right-angled vertex V as the starting point of the direction in which the size of the reflecting element of the unit structure on the xy plane increases, and adjacent sides Sa and Sb as the length L11 in the direction in which the size of the reflecting element of the unit structure on the xy plane increases and the wavelength λ of the electromagnetic wave parallel to the z-axis. The normal direction dn of the hypotenuse Sc of this right-angled triangle RT becomes the reflection direction vector of the electromagnetic wave when the incident direction of the electromagnetic wave is parallel to the z-axis.

[0099] In Figures 14 and 15(a), the direction D11 in which the dimension of the reflective element increases is horizontal to the x-axis, but the direction in which the dimension of the reflective element increases is not limited to this and can be any direction in the xy plane.

[0100] Therefore, in this aspect, the entire surface of the frequency selective reflector is divided into a plurality of divided regions, and the plurality of divided regions include a main region which is a divided region located at the center of the frequency selective reflector, and a plurality of sub-regions which are divided regions other than the main region, and the plurality of sub-regions are arranged around the main region, the frequency selective reflector has a reflecting member that reflects the electromagnetic wave, the reflecting member has a reflection phase control function that controls the reflection phase of the electromagnetic wave, the reflecting member has a plurality of unit structures arranged therein, each unit structure having a plurality of reflecting elements with different dimensions, and each divided area has at least one unit structure; Assuming a three-dimensional orthogonal coordinate system in which the surface of the frequency selective reflector is the xy plane and the normal direction of the surface of the frequency selective reflector is the z axis, and assuming that in the three-dimensional orthogonal coordinate system, the start point of the direction in which the size of the reflecting element of the unit structure on the xy plane increases is a right-angled apex, and the adjacent sides are the length of the direction in which the size of the reflecting element of the unit structure on the xy plane increases and the wavelength of the electromagnetic wave parallel to the z axis, The normal directions of the hypotenuse of the right triangle in each of the divided regions are different from each other, In other words, the normal direction of the hypotenuse of the right triangle in each of the sub-regions is set to expand outward from the normal direction of the hypotenuse of the right triangle in the main region as a center.

[0101] Furthermore, in the case where the relative reflection phase of the electromagnetic wave in each cell region of n unit structures is set so that n unit structures are shifted by n wavelengths (phase difference: n x 360 degrees) as described below, n unit structures are repeatedly arranged in which the direction in which the size of the reflective element of the unit structure increases is the same, and the lengths in the direction in which the size of the reflective element of the unit structure increases are different. In such a case, it is sufficient to imagine a right-angled triangle whose adjacent sides are the sum of the lengths in the direction in which the size of the reflective element of the n unit structures on the xy plane increases and n times the wavelength of the electromagnetic wave parallel to the z axis.

[0102] The shape of the reflective element forming the frequency selective surface is not particularly limited, and may be any shape, such as a ring, a cross, a square, a rectangle, a circle, an ellipse, a bar, a planar pattern such as a pattern divided into multiple adjacent regions, and a three-dimensional structure such as a through-hole via.

[0103] The reflecting element may be a single layer or a multilayer. When the reflecting element is a single layer, the frequency selective plate may be, for example, a plate in which a plurality of reflecting elements are arranged on one side of a dielectric substrate. When the reflecting element is a multilayer, the frequency selective plate may be, for example, a plate in which a plurality of reflecting elements are arranged on both sides of a dielectric substrate, a plate in which a dielectric substrate, a plurality of reflecting elements, a dielectric substrate, and a plurality of reflecting elements are arranged in this order, or a plate in which a one-sided conductor is arranged on the surface farthest from the surface on which the electromagnetic wave is incident.

[0104] In this embodiment, the reflecting member has a reflection phase control function for controlling the reflection phase of the electromagnetic wave. In such a reflecting member, the resonant frequency of each reflecting element can be changed by changing the size and shape of the reflecting element, thereby controlling the reflection phase of the electromagnetic wave. This makes it possible to control the reflection direction of the electromagnetic wave incident from a predetermined direction.

[0105] A typical frequency selective surface can be used as a reflecting member having a reflection phase control function. In either case, it is possible to change the reflection phase of an electromagnetic wave by changing the size and shape of the reflecting element.

[0106] The different dimensions of the reflective elements are appropriately selected depending on the shape of the reflective elements.

[0107] (b) Other configurations The frequency selective reflector of this embodiment may have other configurations in addition to the above-mentioned reflecting members, if necessary.

[0108] (i) Cover member The frequency selective reflector of this embodiment may have a cover member on the electromagnetic wave incident side of the reflector. The cover member can protect the reflector. The cover member can also provide a design.

[0109] (ii) Ground plane The frequency selective reflector of this embodiment may have a ground layer on the surface opposite to the electromagnetic wave incident side of the reflecting member. The ground layer can block interference with an object present on the back surface of the frequency selective reflector and suppress the generation of noise. For example, a conductive layer such as a metal plate, a metal mesh, or an ITO film is used as the ground layer.

[0110] (iii) Planarization layer The frequency selective reflector of this embodiment may have a planarization layer on the electromagnetic wave incident surface of the reflecting member. When the reflecting member is a member in which a plurality of reflecting elements are arranged, the planarization layer can planarize the unevenness caused by the reflecting elements, and can suppress the influence of the unevenness caused by the reflecting elements. An example of the planarization layer is an ionizing radiation cured resin layer arranged in a state in which the reflecting elements are embedded. The planarization layer may also have a function of protecting the reflecting elements.

[0111] (iv) Fixed layer When the frequency selective reflector of this embodiment is used by attaching it to a wall or the like, a fixing layer having a mechanism for attaching the frequency selective reflector may be disposed on the surface of the reflector opposite to the electromagnetic wave incident side. In addition, in order to suppress interference between the fixing layer and the reflector, a metal layer may be disposed between the fixing layer and the reflector, or the fixing layer may also serve as the metal layer. In addition, when the frequency selective reflector of this embodiment is attached to a wall or the like, the fixing layer may have a mechanism for varying the angle of the normal direction of the frequency selective reflector so that the deviation between the designed electromagnetic wave incident direction and reflection direction and the actual electromagnetic wave incident direction and reflection direction can be corrected.

[0112] (2) Second embodiment of frequency selective reflector A second aspect of the frequency selective reflector of this embodiment includes a reflecting member that reflects the electromagnetic wave, and a dielectric layer that is disposed on the electromagnetic wave incident side of the reflecting member, has a concavo-convex structure in which a plurality of unit structures having a thickness distribution that increases in a predetermined direction are disposed, and transmits the electromagnetic wave. In the frequency selective reflector of this embodiment, the unit structures of the dielectric layer have a plurality of cell regions with different thicknesses. In each unit structure of the dielectric layer, the horizontal axis represents the length of the unit structure in the predetermined direction, and the vertical axis represents the relative reflection phase when the electromagnetic wave passes through the dielectric layer, is reflected by the reflecting member, passes through the dielectric layer again, and is emitted to the electromagnetic wave incident side, and the value of the relative reflection phase of the electromagnetic wave is greater than -360 degrees and less than 0 degrees. When points corresponding to the center position in the predetermined direction of each cell region and the relative reflection phase of the electromagnetic wave in each cell region are plotted on a graph, and a straight line passing through the point corresponding to the minimum thickness cell region having the minimum thickness is drawn, each point is on the same straight line, and the dielectric layer has at least unit structures having three or more cell regions with different thicknesses as the unit structures. The reflection direction of the electromagnetic wave is controlled by controlling the relative reflection phase distribution of the electromagnetic wave by the thickness distribution of the dielectric layer.

[0113] 16(a) and (b) are a schematic plan view and a cross-sectional view showing an example of the frequency selective reflector of this embodiment, and FIG. 16(b) is a cross-sectional view taken along the line AA in FIG. 16(a). As shown in FIG. 16(a) and (b), the frequency selective reflector 1 has a reflecting member 2 that reflects a specific electromagnetic wave, and a dielectric layer 5 that is disposed on the electromagnetic wave incident side of the reflecting member 2, has a concavo-convex structure in which a plurality of unit structures 10 having a thickness distribution in which thicknesses t1 to t6 increase in a predetermined direction D3 are arranged, and transmits the specific electromagnetic wave. In addition, the frequency selective reflector 1 has an adhesive layer 6 between the reflecting member 2 and the dielectric layer 5. The unit structures 10 of the dielectric layer 5 have a plurality of cell regions 11a to 11f with different thicknesses t1 to t6. 16(b), for example, the unit structure 10 of the dielectric layer 5 has a step shape in which the thicknesses t1 to t6 increase stepwise in a predetermined direction D3, the number of steps of the step shape is six, and the unit structure 10 of the dielectric layer 5 has six cell regions 11a to 11f. Since the thicknesses t1 to t6 are different in each of the cell regions 11a to 11f of the unit structure 10 of the dielectric layer 5, the round-trip optical path length when the electromagnetic wave transmits through the dielectric layer 5, is reflected by the reflecting member 2, transmits through the dielectric layer 5 again, and is emitted to the electromagnetic wave incident side is different. The difference in the round-trip optical path length in the dielectric layer, that is, the optical path difference, produces a difference in the relative reflection phase.

[0114] The reason why the term "optical path length" is used in this specification is that the wavelengths of the frequency bands covered in this disclosure are closer to those of light and have a higher degree of directivity than conventional pre-LTE frequency bands, and therefore it is easier to explain the behavior of the optical path length as being similar to that of light. In practice, the term "optical path length" refers to the effective distance that an electromagnetic wave travels through a dielectric layer.

[0115] Then, for the unit structure 10 of the dielectric layer 5, the horizontal axis represents the length L of the unit structure 10 in a specified direction D3, and the vertical axis represents the relative reflection phase when the electromagnetic wave passes through the dielectric layer 5, is reflected by the reflecting member 2, passes through the dielectric layer 5 again and is emitted to the incident side of the electromagnetic wave.When the relative reflection phase of the electromagnetic wave has a value greater than -360 degrees and less than 0 degrees, points corresponding to the center position of each cell region in the specified direction D3 and the relative reflection phase of the electromagnetic wave in each cell region are plotted on a graph, and a straight line is drawn passing through the point corresponding to the minimum thickness cell region having the minimum thickness, all of the points are on the same line.

[0116] Fig. 16(c) is a graph in which the horizontal axis represents the length L in a predetermined direction D3 of the unit structure 10 of the dielectric layer 5, and the vertical axis represents the relative reflection phase when the electromagnetic wave passes through the dielectric layer 5, is reflected by the reflecting member 2, passes through the dielectric layer 5 again, and is emitted to the electromagnetic wave incident side, and the value of the relative reflection phase of the electromagnetic wave is greater than -360 degrees and less than 0 degrees, and is an example of the relative reflection phase of the electromagnetic wave in each cell region of the unit structure of the dielectric layer in the frequency selective reflector shown in Fig. 16(a) and (b). As shown in Fig. 16(c), the relative reflection phases of the electromagnetic wave in each cell region 11a to 11f of the unit structure 10 of the dielectric layer 5 are 0 degrees, -60 degrees, -120 degrees, -180 degrees, -240 degrees, and -300 degrees, respectively, and the absolute value of the difference in the relative reflection phase of the electromagnetic wave in adjacent cell regions is 60 degrees. In this case, thicknesses t1 to t6 of the six cell regions 11a to 11f of the unit structure 10 of the dielectric layer 5 are designed so that the absolute value of the difference in the relative reflection phase of the electromagnetic wave in adjacent cell regions is 360 degrees divided by 6, that is, 60 degrees. Then, as shown in Fig. 16(c), when the center positions in a predetermined direction D3 of each of the cell regions 11a to 11f of the unit structure 10 of the dielectric layer 5 and points corresponding to the relative reflection phase of the electromagnetic wave in each of the cell regions 11a to 11f are plotted, and a straight line (solid line in the graph) passing through a point corresponding to the minimum thickness cell region 11a having the minimum thickness t1 among the cell regions 11a to 11f is drawn, each point is on the same straight line.

[0117] The "reflection phase" refers to the amount of change in the phase of a reflected wave relative to the phase of an incident wave incident on a surface. However, in the frequency selective reflector having a reflecting member and a dielectric layer of this embodiment, the "reflection phase" refers to the amount of change in the phase of a reflected wave relative to the phase of an incident wave when the incident wave passes through the dielectric layer, is reflected by the reflecting member, passes through the dielectric layer again, and is emitted.

[0118] In addition, in the frequency selective reflector having the reflecting member and the dielectric layer of this embodiment, the "relative reflection phase" is a negative value that indicates the delay of the reflection phase in a certain cell region with respect to the reference reflection phase, using the reflection phase in the cell region with the smallest reflection phase delay in one unit structure of the dielectric layer as a reference. For example, if the reflection phase in the cell region with the smallest reflection phase delay in one unit structure of the dielectric layer is -10 degrees, the relative reflection phase in the cell region with the reflection phase of -40 degrees will be -30 degrees.

[0119] As described later, when the reflecting member has a reflection phase control function, the relative reflection phase of the electromagnetic wave in the cell region is a value that also includes the reflection phase at the reflecting member.

[0120] In addition, in the frequency selective reflector having the reflecting member and the dielectric layer of this embodiment, the "cell region" refers to a region in the unit structure of the dielectric layer in which the relative reflection phase of electromagnetic waves is the same.

[0121] In the frequency selective reflector having the reflecting member and the dielectric layer of this embodiment, the reflection phase is within a range of more than -360 degrees and less than 360 degrees unless otherwise specified, and -360 degrees and +360 degrees return to 0 degrees. In the frequency selective reflector having the reflecting member and the dielectric layer of this embodiment, the relative reflection phase is within a range of more than -360 degrees and 0 degrees or less unless otherwise specified, and -360 degrees returns to 0 degrees.

[0122] In a conventional reflectarray in which a plurality of reflecting elements are arranged, for example, the reflection phase can be delayed or advanced by adjusting the size and shape of the reflecting elements. On the other hand, in the frequency selective reflector of this embodiment, the reflection phase is basically delayed by adjusting the thickness of each cell region of the unit structure of the dielectric layer. Therefore, the relative reflection phase is based on the reflection phase in the cell region with the smallest reflection phase delay.

[0123] In addition, in one unit structure of the dielectric layer, the cell region with the smallest reflection phase delay is usually the minimum thickness cell region having the smallest thickness in a given direction of thickness increase, and in the above graph, a straight line is drawn passing through the point corresponding to the minimum thickness cell region having the smallest thickness.

[0124] As described above, in each of the cell regions 11a to 11f of the unit structure 10 of the dielectric layer 5, the thicknesses t1 to t6 change, thereby changing the round-trip optical path length in the dielectric layer 5 and changing the relative reflection phase of the electromagnetic wave, so that the electromagnetic wave can be reflected in a direction different from the direct reflection (specular reflection) direction.

[0125] Therefore, in the frequency selective reflector of this embodiment, by changing the thickness of each cell region of the unit structure of the dielectric layer, the round trip optical path length in the dielectric layer can be changed for each cell region, and the reflection phase of the electromagnetic wave can be controlled. This makes it possible to control the reflection direction of the electromagnetic wave relative to a predetermined incident direction to any direction.

[0126] In addition, the uneven structure of the dielectric layer in this embodiment is formed by various methods such as cutting, laser processing, molding using a mold, 3D printer, and bonding of small pieces. Unlike the photolithography processing of the metal layer in the conventional reflect array, a photomask is not required. Therefore, when the thickness of each cell region of the unit structure of the dielectric layer is designed to have the reflection characteristics with the desired incident angle and reflection angle according to the situation and the dielectric layer is formed, the desired dielectric layer can be formed relatively cheaply and in a short period of time, and it is easy to meet the needs of small quantities and various products. In addition, since the thickness of the dielectric layer and the size of the unit structure of the dielectric layer, which affect the control of the reflection characteristics, have a relatively wide processable range, it is possible to increase, for example, the incidence and reflection angles of the electromagnetic wave, and the control range of the reflection characteristics can be widened. Furthermore, since the thickness of the dielectric layer and the pitch of the cell region of the unit structure of the dielectric layer have a relatively wide margin of dimensional processing accuracy to realize the desired reflection phase, it is easy to obtain the desired reflection characteristics and the influence of dimensional variations can be reduced. Therefore, it is easy to customize the reflection characteristics of the frequency selective reflector.

[0127] In the frequency selective reflector of this embodiment, the reflecting member can be a frequency selective plate that reflects only a specific electromagnetic wave. For example, in Fig. 16(a) and (b), the reflecting member 2 is an array of a plurality of ring-shaped reflecting elements 3, and has a dielectric substrate 4 and a plurality of reflecting elements 3 arranged on the surface of the dielectric substrate 4 facing the dielectric layer 5.

[0128] Furthermore, in the frequency selective reflector of this embodiment, the reflecting member can be a frequency selective plate that reflects only a specific electromagnetic wave and has a reflection phase control function that controls the reflection phase of the electromagnetic wave. In such a reflecting member, the resonant frequency can be changed for each reflecting element by changing the size and shape of the reflecting element, and the reflection phase of the target electromagnetic wave can be controlled. In this case, the reflection phase of the electromagnetic wave can be controlled not only by the thickness of the dielectric layer but also by the size and shape of the reflecting element, and the design freedom for controlling the reflection characteristics can be improved.

[0129] Therefore, in the frequency selective reflector of this embodiment, when the above-mentioned reflecting member is used, the degree of freedom of control of the reflection characteristics can be increased by combining it with the above-mentioned dielectric layer. Therefore, it is possible to more easily customize the reflection characteristics of the frequency selective reflector. For example, one example is to prepare multiple types of reflection characteristics in the vertical direction with the reflecting member and combine them with a dielectric layer that adjusts the reflection characteristics in the horizontal direction.

[0130] In addition, the inventors of the present disclosure conducted a simulation of the reflection characteristics of electromagnetic waves in a specific frequency band when the reflection member is a frequency selective plate having a reflection element that reflects only specific electromagnetic waves in the frequency selective reflector having the reflection member and the dielectric layer of this embodiment, and found that the reflection phase shift when the thickness of the cell region of the unit structure of the dielectric layer is changed to change the round trip optical path length in the dielectric layer for each cell region is larger than the reflection phase shift in the reflection element due to the proximity of the dielectric layer to the reflection member (frequency selective plate), and that the design of the substantial reflection characteristics can be determined almost entirely by the design of the concave-convex structure of the dielectric layer. In this case, the resonance frequency of the reflection element varies depending on the presence or absence of a nearby dielectric layer, but if the design is made on the premise that the dielectric layer exists, the practical problem is solved. Furthermore, it was found that the in-plane arrangement of the concave-convex structure of the dielectric layer that realizes the in-plane distribution design of the reflection phase in the frequency selective reflector does not need to be in a fixed positional relationship with the in-plane arrangement of the reflection element of the reflection member, and that the reflection characteristics are not significantly affected even if the concave-convex structure of the dielectric layer is arranged to be shifted from the in-plane arrangement of the reflection element.

[0131] Therefore, in the frequency selective reflector of this embodiment, when the dielectric layer and the reflecting member as described above are combined, the dielectric layer and the reflecting member can be designed independently and combined. In this case, a dielectric layer that realizes the reflection characteristics according to the use environment may be prepared each time, or multiple specifications may be prepared in advance. Therefore, the reflection direction design of the frequency selective reflector that changes according to the use environment can be customized more easily, and it becomes easy to apply to various situations. As described above, when the overall reflection characteristics of the frequency selective reflector are adjusted by combining the reflection phase distributions of the reflection member and the dielectric layer, the accuracy of the misalignment of the reflection member and the dielectric layer is required according to the required specifications, but when the reflection characteristics of the frequency selective reflector are adjusted only by the reflection phase distribution of the dielectric layer, the accuracy of the misalignment of the reflection member and the dielectric layer is not required very much.

[0132] In this embodiment, since the reflection direction vectors of the electromagnetic waves are different in each of the divided regions, the dielectric layer can have a plurality of types of unit structures with different reflection direction vectors of the electromagnetic waves according to the reflection characteristics of each of the divided regions. In this embodiment, each of the divided regions can have at least one unit structure, and may have a plurality of unit structures with the same reflection direction vector of the electromagnetic waves. In addition, when the number of divided regions is increased to design a gradual change in the reflection direction vector over the entire surface of the frequency selective reflector, each of the divided regions may have at least one cell region.

[0133] Here, in this embodiment, the reflection direction vector of the electromagnetic wave can be determined as follows. In this embodiment, the thickness of the cell region repeatedly increases and decreases in a certain direction. For example, in a reflecting member, when the dimensions of a plurality of reflecting elements are equal, the reflection direction vector can be determined by the length of the unit structure in the direction in which the thickness of the cell region increases and the wavelength of the electromagnetic wave. Specifically, first, as illustrated in FIG. 6, a case is assumed in which the frequency selective reflector 1 is vertically set on the ground (xz plane), and a three-dimensional orthogonal coordinate system is assumed based on the horizontal direction (x-axis), the up-down direction (y-axis), and the normal direction (z-axis). This three-dimensional orthogonal coordinate system is a three-dimensional orthogonal coordinate system in which the surface of the frequency selective reflector 1 is the xy plane, and the normal direction to the surface of the frequency selective reflector 1 is the z axis. Next, the direction in which the dimensions of the reflecting element increase in the xy plane is obtained. For example, in the case of FIG. 16(a) and (b), the direction in which the thicknesses t1 to t6 of the cell regions 11a to 11f increase in the xy plane is indicated by the direction D12. Next, the length of the unit structure in the direction in which the thickness of the cell region increases on the xy plane is obtained. For example, in the case of Fig. 16(a) and (b), the length of the direction D12 in which the thicknesses t1 to t6 of the cell regions 11a to 11f of the unit structure 10 increase on the xy plane is indicated by length L12. Next, in the above three-dimensional orthogonal coordinate system, the wavelength of the electromagnetic wave is taken parallel to the z-axis. Then, a right-angled triangle is created with the right-angled apex being the starting point of the direction in which the thickness of the cell region of the unit structure on the xy plane increases, and the length of the direction in which the thickness of the cell region of the unit structure on the xy plane increases and the wavelength of the electromagnetic wave parallel to the z-axis as adjacent sides. The normal direction of the hypotenuse of this right-angled triangle is the reflection direction vector of the electromagnetic wave when the incident direction of the electromagnetic wave is parallel to the z-axis. 17(a) and (b), for example, in the above three-dimensional orthogonal coordinate system, a right-angled triangle RT is created with the right-angled vertex V as the starting point of the direction in which the thickness of the cell area of ​​the unit structure on the xy plane increases, and adjacent sides Sa and Sb as the length L12 in the direction in which the thickness of the cell area of ​​the unit structure on the xy plane increases and the wavelength λ of the electromagnetic wave parallel to the z-axis. The normal direction dn of the hypotenuse Sc of this right-angled triangle RT becomes the reflection direction vector of the electromagnetic wave when the incident direction of the electromagnetic wave is parallel to the z-axis.

[0134] In Figures 16(a), (b) and 17(a), the direction D12 in which the thickness of the cell region increases is horizontal to the x-axis, but the direction in which the thickness of the cell region increases is not limited to this and can be any direction in the xy plane.

[0135] Therefore, in this aspect, the entire surface of the frequency selective reflector is divided into a plurality of divided regions, and the plurality of divided regions include a main region which is a divided region located at the center of the frequency selective reflector, and a plurality of sub-regions which are divided regions other than the main region, and the plurality of sub-regions are arranged around the main region, the frequency selective reflector includes a reflecting member that reflects the electromagnetic wave, and a dielectric layer that is disposed on an incident side of the electromagnetic wave with respect to the reflecting member, has a concavo-convex structure in which a plurality of unit structures having a thickness distribution in which the thickness increases in a predetermined direction are disposed, and transmits the electromagnetic wave, the unit structure of the dielectric layer has a plurality of cell regions having different thicknesses, and each of the divided regions has at least one unit structure, Assuming a three-dimensional orthogonal coordinate system in which the surface of the frequency selective reflector is the xy plane and the normal direction to the surface of the frequency selective reflector is the z axis, and assuming that in the three-dimensional orthogonal coordinate system, the start point of the direction in which the thickness of the cell region of the unit structure on the xy plane increases is a right-angled apex, and the adjacent sides are the length of the direction in which the thickness of the cell region of the unit structure on the xy plane increases and the wavelength of the electromagnetic wave parallel to the z axis, The normal directions of the hypotenuse of the right triangle in each of the divided regions are different from each other, In other words, the normal direction of the hypotenuse of the right triangle in each of the sub-regions is set to expand outward from the normal direction of the hypotenuse of the right triangle in the main region as a center.

[0136] Furthermore, as described below, in the case where the relative reflection phase of the electromagnetic wave in each cell area of ​​n unit structures is set so that there is a shift of n wavelengths (phase difference: n x 360 degrees) for n unit structures, n unit structures are repeatedly arranged in which the direction in which the thickness of the cell area of ​​the unit structure increases is the same, and the lengths in the direction in which the thickness of the cell area of ​​the unit structure increases are different. In such a case, it is sufficient to imagine a right-angled triangle whose adjacent sides are the sum of the lengths in the direction in which the thickness of the cell areas of the n unit structures on the xy plane increases and n times the wavelength of the electromagnetic wave parallel to the z axis.

[0137] 22, for example, the relative reflection phase of the electromagnetic wave in each cell area of ​​the two unit structures 10a and 10b is set so that it is shifted by two wavelengths (phase difference: 720 degrees) due to the two unit structures 10a and 10b. In this case, it is sufficient to imagine a right-angled triangle with adjacent sides that are twice the wavelength of the electromagnetic wave parallel to the z-axis, with the left end of unit structure 10a as the right-angled apex, as the starting point of the direction in which the thickness of the cell area of ​​the unit structure on the xy plane increases, and the total length of the direction in which the thickness of the cell areas of the two unit structures 10a and 10b on the xy plane increases being L1+L2.

[0138] Each component of the frequency selective reflector of this embodiment will be described below.

[0139] (a) Dielectric layer The dielectric layer in the present disclosure is a member that is arranged on the electromagnetic wave incident side with respect to the reflecting member, has a concavo-convex structure in which a plurality of unit structures having a thickness distribution in which the thickness increases in a predetermined direction are arranged, and transmits electromagnetic waves of a specific frequency band. The unit structure of the dielectric layer has a plurality of cell regions with different thicknesses, and in each unit structure of the dielectric layer, the horizontal axis represents the length of the unit structure in a predetermined direction, and the vertical axis represents the relative reflection phase when the electromagnetic wave transmits through the dielectric layer, is reflected by the reflecting member, transmits through the dielectric layer again, and is emitted to the electromagnetic wave incident side. When the center position of each cell region in a predetermined direction and the relative reflection phase of the electromagnetic wave in each cell region are plotted on a graph in which the value of the relative reflection phase of the electromagnetic wave is greater than -360 degrees and less than 0 degrees, and a straight line passing through the point corresponding to the minimum thickness cell region having the minimum thickness is drawn, each point is on the same straight line. The dielectric layer also has, as a unit structure, at least a unit structure having three or more cell regions with different thicknesses.

[0140] (i) Dielectric layer structure The dielectric layer has a concave-convex structure in which a plurality of unit structures having a thickness distribution in which the thickness increases in a predetermined direction are arranged.

[0141] The unit structure of the dielectric layer has a plurality of cell regions of different thicknesses, and for each unit structure of the dielectric layer, the length of the unit structure in the above-mentioned specified direction is plotted on the horizontal axis, and the relative reflection phase when the electromagnetic wave passes through the dielectric layer, is reflected by the reflective member, passes through the dielectric layer again and is emitted to the electromagnetic wave incident side is plotted on the vertical axis, and points corresponding to the center position of each cell region in the above-mentioned specified direction and the relative reflection phase of the electromagnetic wave in each cell region are plotted on a graph in which the value of the relative reflection phase of the electromagnetic wave is greater than -360 degrees and less than 0 degrees, and when a straight line is drawn through the point corresponding to the minimum thickness cell region having the minimum thickness, all of the points are on the same line.

[0142] Here, each point being on the same line means that the difference in the vertical direction of each point with respect to the line is within ±72 degrees. The difference in the vertical direction of each point with respect to the above line is preferably within ±54 degrees, more preferably within ±36 degrees, and even more preferably within ±18 degrees. If each point includes a deviation in the vertical direction with respect to the above line and it is difficult to draw a straight line passing through each point, consider "a straight line connecting a point corresponding to the minimum thickness cell region having the minimum thickness (relative reflection phase 0 degrees) and a point corresponding to the minimum thickness cell region having the minimum thickness in the unit structure adjacent to that unit structure (considered to have a relative reflection phase of -360 degrees)."

[0143] The unit structure of the dielectric layer has a thickness distribution in which the thickness increases in a predetermined direction. The unit structure of the dielectric layer may have a thickness distribution in which the thickness increases only in one direction, or may have a thickness distribution in which the thickness increases in two directions, a first direction and a second direction perpendicular to the first direction. For example, FIG. 18(a) is an example in which the unit structure 10 of the dielectric layer has a thickness distribution in which the thickness increases only in the first direction D3, and FIG. 18(c), (e), and FIG. 19(a) are examples in which the unit structure 10 of the dielectric layer has a thickness distribution in which the thickness increases in the first direction D3 and the second direction D4.

[0144] When the unit structure of the dielectric layer has a thickness distribution in which the thickness increases in only one direction, the points will be on the same line when plotted on the graph with the horizontal axis representing the length of the unit structure in that one direction. Also, when the unit structure of the dielectric layer has a thickness distribution in which the thickness increases in two mutually perpendicular directions, the points will be on the same line when plotted on the graph with the horizontal axis representing the length of the unit structure in the two directions.

[0145] In one unit structure of the dielectric layer, the absolute value of the difference in the relative reflection phase of the electromagnetic wave between adjacent cell regions is less than 180 degrees, preferably 120 degrees or less, and more preferably 60 degrees or less. The smaller the absolute value of the difference in the relative reflection phase of the electromagnetic wave between adjacent cell regions, the smoother the wavefront of the reflected wave can be. Also, the absolute value of the difference in the relative reflection phase of the electromagnetic wave between adjacent cell regions is more than 0 degrees.

[0146] In addition, in the case where the maximum thickness cell region having the maximum thickness in one unit structure and the minimum thickness cell region having the minimum thickness in the other unit structure are adjacent to each other in adjacent unit structures, when the relative reflection phase of the electromagnetic wave in the minimum thickness cell region having the minimum thickness in the other unit structure is expressed as more than -720 degrees and less than -360 degrees, which is shifted by one period, based on the reflection phase in the cell region having the smallest reflection phase delay in one unit structure, the absolute value of the difference between the relative reflection phase of the electromagnetic wave in the maximum thickness cell region having the maximum thickness in one unit structure and the relative reflection phase of the electromagnetic wave in the minimum thickness cell region having the minimum thickness in the other unit structure is less than 180 degrees, preferably 120 degrees or less, and more preferably 60 degrees or less. The smaller the absolute value of the difference in the relative reflection phase of the electromagnetic wave in these adjacent cell regions, the smoother the wavefront of the reflected wave can be. In addition, the absolute value of the difference in the relative reflection phase of the electromagnetic wave in these adjacent cell regions is more than 0 degrees. For example, in Figure 16(c), in adjacent unit structures 10a and 10b, the relative reflection phase of the electromagnetic wave in the maximum thickness cell region 11f having the maximum thickness t6 of one unit structure 10a is -300 degrees, and the relative reflection phase of the electromagnetic wave in the minimum thickness cell region 11a having the minimum thickness t1 of the other unit structure 10b is -360 degrees, and the absolute value of the difference between the relative reflection phase of the electromagnetic wave in the maximum thickness cell region 11f having the maximum thickness t6 of one unit structure 10a and the relative reflection phase of the electromagnetic wave in the minimum thickness cell region 11a having the minimum thickness t1 of the other unit structure 10b is 60 degrees.

[0147] In addition, in one unit structure of the dielectric layer, the difference in the relative reflection phase of the electromagnetic wave in the adjacent cell regions is preferably equal. For example, as shown in Fig. 16(b), when the unit structure 10 of the dielectric layer 5 has six cell regions, the difference in the relative reflection phase of the electromagnetic wave in the adjacent cell regions 11a and 11b, the difference in the relative reflection phase of the electromagnetic wave in the adjacent cell regions 11b and 11c, the difference in the relative reflection phase of the electromagnetic wave in the adjacent cell regions 11c and 11d, the difference in the relative reflection phase of the electromagnetic wave in the adjacent cell regions 11d and 11e, and the difference in the relative reflection phase of the electromagnetic wave in the adjacent cell regions 11e and 11f are preferably equal to each other. For example, in Fig. 16(c), the absolute values ​​of the difference in the relative reflection phase of the electromagnetic wave in the adjacent cell regions are all 60 degrees, and are equal to each other.

[0148] Furthermore, in adjacent unit structures, when a maximum thickness cell region having the maximum thickness in one unit structure and a minimum thickness cell region having the minimum thickness in the other unit structure are adjacent to each other, when the reflection phase in the cell region with the smallest reflection phase delay in one unit structure is used as a reference and the relative reflection phase of the electromagnetic wave in the minimum thickness cell region having the minimum thickness in the other unit structure is expressed as more than -720 degrees and less than -360 degrees, which is shifted by one period, it is preferable that the difference in the relative reflection phase of the electromagnetic wave in the adjacent cell regions is equal, including not only all cell regions in one unit structure but also the minimum thickness cell region having the minimum thickness in the other unit structure. For example, in Figure 16(c), in adjacent unit structures 10a and 10b, the relative reflection phase of the electromagnetic wave at each cell region 11a to 11f of one unit structure 10a is 0 degrees, -60 degrees, -120 degrees, -180 degrees, -240 degrees, and -300 degrees, respectively, and the relative reflection phase of the electromagnetic wave at the minimum thickness cell region 11a having the minimum thickness t1 of the other unit structure 10b is -360 degrees.The absolute values ​​of the difference in the relative reflection phase of the electromagnetic wave at adjacent cell regions, including all cell regions 11a to 11f in one unit structure 10a and the minimum thickness cell region 11a having the minimum thickness t1 in the other unit structure 10b, are all 60 degrees, which is equal.

[0149] In addition, in one unit structure of the dielectric layer, the absolute value of the difference between the relative reflection phase of the electromagnetic wave in the minimum thickness cell region having the minimum thickness and the relative reflection phase of the electromagnetic wave in the maximum thickness cell region having the maximum thickness is less than 360 degrees. In addition, in one unit structure of the dielectric layer, the absolute value of the difference between the relative reflection phase of the electromagnetic wave in the minimum thickness cell region having the minimum thickness and the relative reflection phase of the electromagnetic wave in the maximum thickness cell region having the maximum thickness must be greater than 180 degrees, and is more preferably 300 degrees or more and less than 360 degrees. For example, as shown in FIG. 16(b), in a case where the unit structure 10 of the dielectric layer 5 has six cell regions, the absolute value of the difference between the relative reflection phase of the electromagnetic wave in the minimum thickness cell region 11a having the minimum thickness t1 and the relative reflection phase of the electromagnetic wave in the maximum thickness cell region 11f having the maximum thickness t6 in one unit structure 10 is preferably less than 360 degrees. For example, in Figure 16(c), in one unit structure 10 of the dielectric layer 5, the relative reflection phase of the electromagnetic wave in the minimum thickness cell region 11a having the minimum thickness t1 is 0 degrees, the relative reflection phase of the electromagnetic wave in the maximum thickness cell region 11f having the maximum thickness t6 is -300 degrees, and the absolute value of the difference between the relative reflection phase of the electromagnetic wave in the minimum thickness cell region 11a having the minimum thickness t1 and the relative reflection phase of the electromagnetic wave in the maximum thickness cell region 11f having the maximum thickness t6 is 300 degrees.

[0150] The size of the unit structure of the dielectric layer, specifically, the length of the unit structure in a predetermined direction in which the thickness increases, is appropriately set according to the target reflection characteristics. The reflection angle can be adjusted because the length of the unit structure in the predetermined direction in which the thickness increases causes a shift of one wavelength (phase difference: 360 degrees). For example, by shortening the length of the unit structure in the predetermined direction in which the thickness increases, the difference between the reflection angle and the specular reflection angle can be increased, while by increasing the length of the unit structure in the predetermined direction in which the thickness increases, the difference between the reflection angle and the specular reflection angle can be reduced.

[0151] The cross-sectional shape of the unit structure of the dielectric layer may be, for example, a step shape in which the thickness increases stepwise in a predetermined direction, or a tapered shape in which the thickness increases gradually in a predetermined direction. Fig. 16(b) is an example in which the unit structure 10 of the dielectric layer 5 has a step shape. Fig. 20 is an example in which the unit structure 10 of the dielectric layer 5 has a tapered shape.

[0152] In addition, the unit structure of the dielectric layer has a plurality of cell regions with different thicknesses, but when the cross-sectional shape of the unit structure of the dielectric layer has a tapered shape, the number of cell regions in the unit structure can be regarded as being infinitely large. Even in this case, the thickness distribution of the unit structure is designed so that the relative reflection phase of the electromagnetic wave in each cell region is set as described above.

[0153] In addition, since the dielectric layer is an arrangement of a plurality of unit structures having a thickness distribution, the pattern shape of the unit structures in plan view may be any shape that allows them to be arranged without gaps, such as a rectangle, a regular hexagon, etc. Figures 18(a) to (f) and 19(a) show examples in which the pattern shape of the unit structures 10 of the dielectric layer in plan view is rectangular.

[0154] In the unit structure of the dielectric layer, the difference in the round-trip optical path length between adjacent cell regions is designed so that the relative reflection phase of the electromagnetic wave in each cell region is set as described above, and the thickness of each cell region is set so that the difference in thickness between adjacent cell regions is the difference in the round-trip optical path length between the adjacent cell regions. The thickness of each cell region is appropriately set according to the wavelength of the electromagnetic wave, the dielectric constant of the material of the dielectric layer, and the desired reflection characteristics. For example, the effective wavelength of the electromagnetic wave passing through the dielectric is λ g If the thickness of the base is α, the thickness of each cell area is α+0λ g Above, α+2λ g The thickness α of the base can be the same as the minimum thickness of the minimum thickness cell region having the minimum thickness in one unit structure of the dielectric layer. The thickness α of the base is appropriately set in consideration of the overall strength, ease of formation, etc., but is usually set to 0.1λ in consideration of the effect on electromagnetic waves.g It is preferable that the thickness of each cell region is about 0 mm or more and 8.6 mm or less. Specifically, when the wavelength λ0 of the electromagnetic wave in air is 10 mm and the relative dielectric constant of the dielectric layer is 2.57, it is preferable that the thickness of each cell region is 0 mm or more and 8.6 mm or less. Note that when the thickness of a cell region is 0 mm, it means that no dielectric layer is formed in the cell region located on the reflective member.

[0155] In the unit structure of the dielectric layer, the pitch and width of the cell regions are appropriately set.

[0156] Furthermore, when the reflective member is a member in which a plurality of reflective elements are arranged, the pitch of the cell regions of the unit structures of the dielectric layer may be the same as or different from the pitch of the reflective elements of the reflective member. When the pitch of the cell regions of the unit structures of the dielectric layer is the same as the pitch of the reflective elements of the reflective member, the design is easy. Furthermore, for example, by narrowing the pitch of the cell regions of the unit structures of the dielectric layer while maintaining the difference in the relative reflection phase of the electromagnetic waves between adjacent cell regions, the control range of the reflection characteristics can be expanded regardless of the pitch of the reflective elements of the reflective member.

[0157] In addition, in one unit structure of the dielectric layer, the pitch of the cell regions is preferably uniform.

[0158] The pitch of the cell regions means the distance from the center of one cell region to the center of an adjacent cell region.

[0159] In addition, in one unit structure of the dielectric layer, the width of the cell region in a given direction in which the thickness increases is preferably equal.

[0160] In the unit structure of the dielectric layer, the pattern shape of the cell region in plan view may be, for example, a stripe shape, a shape obtained by dividing a concentric square into four equal parts by straight lines parallel to the sides and perpendicular to each other, a microarray shape, a concentric quadrant shape which is a shape obtained by dividing a concentric circle into four equal parts by diameters perpendicular to each other, a curved staircase shape, etc. For example, Fig. 18(b) is an example of a stripe shape, Fig. 18(d) is an example of a shape obtained by dividing a concentric square into four equal parts by straight lines parallel to the sides and perpendicular to each other, Fig. 18(f) and Fig. 19(a) are examples of a microarray shape, Fig. 19(b) is an example of a concentric quadrant shape, and Fig. 19(c) is an example of a curved staircase shape. Note that Fig. 18(b) is a top view of Fig. 18(a), Fig. 18(d) is a top view of Fig. 18(c), and Fig. 18(f) is a top view of Fig. 18(e). Furthermore, when these exemplified unit structures are arranged without any gaps, there are no particular restrictions on the arrangement direction. For example, rectangular unit structures can be arranged over the entire surface while being rotated 30 degrees clockwise in a planar view. The unit structures can be arranged at an appropriate angle and in an appropriate arrangement direction depending on the required reflection characteristic design.

[0161] The unit structure of the dielectric layer has a plurality of cell regions. In one unit structure of the dielectric layer, the number of cell regions is, for example, 3 or more, and preferably 6 or more. The greater the number of cell regions in one unit structure of the dielectric layer, the smaller the difference in relative reflection phase of the electromagnetic wave in the adjacent cell regions can be, and the smoother the wave front of the reflected wave can be. In addition, the greater the number of cell regions in one unit structure of the dielectric layer, the more preferable it is, and the upper limit is not particularly limited. In addition, when the cross-sectional shape of the unit structure is a step shape, the number of cell regions corresponds to the number of steps of the step shape. In addition, when the cross-sectional shape of the unit structure is a tapered shape, as described above, the tapered shape can be regarded as an infinitely large number of cell regions.

[0162] As described above, the dielectric layer has a plurality of types of unit structures with different reflection direction vectors of electromagnetic waves according to the reflection characteristics of the main region and each sub-region. In this embodiment, each of the main region and each sub-region may have at least one unit structure, and may have a plurality of unit structures with the same reflection direction vector of electromagnetic waves.

[0163] In the unit structure, the reflection characteristics can be varied by varying at least one of the length of the unit structure in the direction in which the thickness increases, the thickness distribution, the number, width, pitch, the pattern shape in a planar view of the unit structure, and the pattern shape in a planar view of the cell regions.

[0164] For example, the length of the unit structure in the direction of thickness increase in the dielectric layer may be different, and the cell region may have a striped pattern in plan view. For example, in Fig. 21(a), the dielectric layer 5 has three types of unit structures 10a, 10b, 10c, and 10d with different reflection characteristics, and the unit structures 10a, 10b, 10c, and 10d have different lengths L1, L2, and L3 in a predetermined direction D3, and the numbers of the cell regions 11a to 11g, 12a to 12f, and 13a to 13e are different. As a result, as shown in Figure 21(b), the relative reflection phases of the electromagnetic wave at each cell region 11a to 11g of unit structure 10a are 0 degrees, -51.4 degrees, -103 degrees, -154 degrees, -206 degrees, -257 degrees, and -309 degrees, respectively, the relative reflection phases of the electromagnetic wave at each cell region 12a to 12f of unit structures 10b and 10c are 0 degrees, -60 degrees, -120 degrees, -180 degrees, -240 degrees, and -300 degrees, respectively, and the relative reflection phases of the electromagnetic wave at each cell region 13a to 13e of unit structure 10d are 0 degrees, -72 degrees, -144 degrees, -216 degrees, and -288 degrees, respectively, so that the reflection characteristics of unit structures 10a and 10b, and 10c and 10d are different from each other. Although not shown, the cell regions 11a to 11g, 12a to 12f, and 13a to 13e have a striped pattern in plan view. In this case, the polar angle θ of the reflection direction of the electromagnetic wave can be increased in the order of unit structure 10a<10b=10c<10d. In the above case, unit structures 10b and 10c are the main region, and unit structures 10a and 10c are the sub-regions.

[0165] In addition, in the dielectric layer, the relative reflection phase of the electromagnetic wave in each cell region of n unit structures may be set so that the n unit structures are shifted by n wavelengths (phase difference: n × 360 degrees). Here, n is an integer of 2 or more. Figs. 22(a) to (c) show an example in which the dielectric layer 5 has two different types of unit structures 10a and 10b, and the relative reflection phase of the electromagnetic wave in each cell region 11a to 11c, 12a to 12b of the two unit structures 10a and 10b is set so that the two unit structures 10a and 10b are shifted by two wavelengths (phase difference: 720 degrees). Here, Fig. 22(b) is a graph in which the range of the relative reflection phase of the electromagnetic wave is expressed as more than -360 degrees and less than 0 degrees. Fig. 22(c) is a graph in which the range of the relative reflection phase of the electromagnetic wave is more than -720 degrees and less than 0 degrees, and the points of substantially the same phase where the relative reflection phase is shifted by 360 degrees are complemented. In these unit structures 10a, 10b, lengths L1, L2 of the unit structures in a predetermined direction D3 are different from each other, and the numbers of cell regions 11a to 11c, 12a to 12b are different from each other.

[0166] In the above case, one unit structure 10a has three cell regions 11a to 11c, while the other unit structure 10b has two cell regions 12a and 12b. The dielectric layer has at least a unit structure having three or more cell regions with different thicknesses as a unit structure, but may further have a unit structure having two cell regions with different thicknesses as described above.

[0167] Furthermore, in each divided region, the thickness distribution of the dielectric layer can be appropriately selected and multiple unit structures can be arranged so that the normal vector of the same phase plane of the reflected wave for the incident wave incident at a predetermined incident angle becomes the desired reflection direction vector. For example, when the incident wave is reflected in a single direction, that is, as a so-called plane wave, it is preferable that only multiple unit structures having the same reflection characteristics are arranged in each divided region, and it is more preferable that the length of the unit structures in the direction of increasing thickness is the same and that the pattern shape of the cell region in a planar view is striped.

[0168] Although Figure 16(a) shows an arrangement in which the longitudinal direction of the stripes in the cell region is parallel to the short side direction of the frequency selective reflector, this is not limited to this, and in an actual frequency selective reflector, the longitudinal and short side directions of the stripes in the cell region are set according to the design of the reflection characteristics.

[0169] In addition, when the incident wave and the reflected wave are plane waves, the dielectric layer has a periodic structure in which unit structures are repeatedly arranged. The term "periodic structure" refers to a structure in which unit structures are periodically and repeatedly arranged. In the unit structures in the periodic structure, the unit structures having the same reflection characteristics can have the same length, thickness distribution, number, width, and pitch of the unit structures in the direction of increasing thickness, pattern shape of the unit structures in a planar view, and pattern shape of the cell regions in a planar view. In addition, even when the dielectric layer has a periodic structure, as described above, unit structures having different reflection characteristics can be combined. In this case, the reflection characteristics of the unit structures to be combined are appropriately designed according to the desired reflection characteristics, and specifically, the length, thickness distribution, number, width, and pitch of the unit structures in the direction of increasing thickness, pattern shape of the unit structures in a planar view, and pattern shape of the cell regions in a planar view, in the unit structures to be combined, are appropriately set according to the desired reflection characteristics.

[0170] Generally, in designing reflection characteristics that reflect a plane wave as a plane wave in a direction different from the regular reflection direction, the design can be achieved by, for example, decomposing the reflection characteristics into the in-plane x direction and in-plane y direction of the reflector, converting them into reflection phase distributions in the x and y directions, and incorporating them as the thickness distribution of the unit structure. As shown in Figure 23, an example will be explained using a portion of a frequency selective reflector in which 10 x 10 (i = 10, j = 10) cell areas of the same size, in which the reflection phase can be adjusted individually, are arranged. At this time, it should be noted that the 10 x 10 size of the cell areas is not necessarily the size of the unit structure. The angle of incidence (θ in , φ in ) is reflected at an angle (θ out , φ out ) reflection phase δ required for the cell area at position (i, j) when a plane wave is reflected in the directioni,j is given by the following equation:

[0171] δ i,j =2π{p×i×(sinθ out ×cosφ out -sinθ in ×cosφ in )+ p×j×(sinθ out ×sinφ out -sinθ in ×sinφ in )} / λ Here, in the above formula, δ i,j : Reflection phase of a cell area located at (i,j) relative to the phase center (0,0) λ: Wavelength of reflected wave [m] p: Cell area size [m] θ in : θ inclination of the incident wave φ in : Incident wave φ gradient θ out : θ gradient of reflected wave φ out : φ gradient of reflected wave Shows.

[0172] The dielectric layer may be a single layer or may be a multilayer. The dielectric layer may have a base material portion as a base and an uneven portion disposed on the base material. The dielectric layer may be a single member in which all the cell regions are integrally formed, or may be a layer in which the individual cell regions are formed separately and the cell regions are arranged in a block shape.

[0173] (ii) Characteristics of the dielectric layer The dielectric layer is required to transmit electromagnetic waves in a specific frequency band, and may or may not transmit electromagnetic waves in other frequency bands.

[0174] The dielectric loss tangent of the dielectric layer is preferably relatively small. The small dielectric loss tangent of the dielectric layer can reduce the dielectric loss and the high frequency loss. Specifically, the dielectric loss tangent of the dielectric layer for the electromagnetic wave of the target frequency is preferably 0.01 or less. The smaller the dielectric loss tangent of the dielectric layer, the more preferable it is, and the lower limit is not particularly limited.

[0175] In addition, the dielectric constant of the dielectric layer is preferably relatively high. By having a high dielectric constant of the dielectric layer, it is expected that the thickness of the dielectric layer can be reduced. Specifically, the dielectric constant of the dielectric layer for electromagnetic waves of the target frequency is preferably 2 or more, more preferably 2.5 or more, and even more preferably 3 or more when the difference between the reflection angle and the specular reflection angle is increased.

[0176] The dielectric loss tangent and dielectric constant of the dielectric layer are measured by a resonator method in accordance with JIS C 2138:2007.

[0177] (iii) Material of the dielectric layer The material of the dielectric layer is not particularly limited as long as it is a dielectric that can transmit a predetermined electromagnetic wave, and resin, glass, quartz, ceramics, etc. can be used. Among them, resin is preferable in consideration of the ease of forming the uneven structure.

[0178] The resin is not particularly limited as long as it can transmit a predetermined electromagnetic wave, but it is preferable that the resin absorbs the electromagnetic wave relatively little and transmits the electromagnetic wave relatively high. In addition, the resin preferably satisfies the above-mentioned dielectric tangent, and more preferably satisfies the above-mentioned dielectric constant. Examples of such resins include polycarbonate, acrylic resin, ABS resin, PLA resin, olefin resin, and copolymers thereof. Among them, polycarbonate is preferable because it has excellent dimensional stability and low high-frequency loss.

[0179] The dielectric layer may further contain a filler. The dielectric layer may contain a filler, thereby adjusting the dielectric constant and mechanical strength of the dielectric layer. The dielectric constant of the filler is preferably higher than the dielectric constant of the resin. This allows the dielectric constant of the dielectric layer to be increased, and the required thickness of the dielectric layer to be reduced. The high dielectric constant filler is not particularly limited, and examples thereof include inorganic particles and fine fibers such as glass, silica, and barium titanate.

[0180] The material, shape, size, and content of the filler can be appropriately selected based on the desired dielectric constant, mechanical strength, degree of dispersibility, etc. The size of the filler must be sufficiently smaller than the effective wavelength of the electromagnetic wave passing through the dielectric, and the effective wavelength of the electromagnetic wave is set to λ g In this case, the diameter of the filler equivalent to a sphere is, for example, 0.01λ g It is preferable that the filler content is less than 100%. However, when the size of the filler approaches the nanometer order, uniform dispersion tends to be difficult, and the load of the processing process may increase. The content of the filler in the dielectric layer varies depending on the combination of the dielectric and filler materials, the shape of the filler, the size of the filler, etc., and is adjusted appropriately.

[0181] In addition, when the concave-convex structure of the dielectric layer is formed by molding using a mold, etc., a release agent, an antistatic agent, etc. may be added to the dielectric layer. These can be selected from general agents as appropriate. In addition, it is preferable that the dielectric layer does not contain additives or fillers that impart conductivity, such as carbon black or metal particles.

[0182] (iv) Method for forming dielectric layer The method of forming the dielectric layer is not particularly limited as long as it is a method capable of forming a predetermined uneven structure, and examples thereof include cutting of a resin sheet, laser processing, molding using a mold, vacuum casting, modeling using a 3D printer, joining of small pieces, etc. In the case of a forming method that does not use a mold, such as cutting, laser processing, or 3D printer, customization according to the target reflection angle is easy, so it can be suitably used for tuning the design when designing and developing a special installation situation or a large-scale frequency selective reflector that is difficult to simulate. In the case of molding using a mold, molding may be performed on a substrate made of a dielectric, and in this case, the substrate and the molding resin may be made of different materials as long as they are materials that transmit a predetermined electromagnetic wave. Furthermore, for example, in the case where the reflective member and the dielectric layer are designed and manufactured separately, multiple types of dielectric layers having reflection characteristics with predetermined angles of incidence and reflection angles are prepared in advance, the type of dielectric layer is selected according to the situation, and the dielectric layer is rotated in-plane relative to the reflective member around the normal direction as an axis to fine-tune the reflection direction of the electromagnetic wave, it may be more cost-effective to manufacture dielectric layers of the same specifications collectively, in which case a molding technique using a mold is preferable.

[0183] (b) Reflective material The reflective member in this embodiment is a member that reflects electromagnetic waves in a specific frequency band.

[0184] The reflective member is not particularly limited as long as it reflects electromagnetic waves in a specific frequency band, and may be, for example, a member that reflects only electromagnetic waves in a specific frequency band, or may be a member that reflects not only electromagnetic waves in a specific frequency band but also electromagnetic waves in other frequency bands. In particular, it is preferable that the reflective member has a wavelength selection function that reflects only electromagnetic waves in a specific frequency band.

[0185] An example of a reflective member that reflects not only electromagnetic waves in a specific frequency band but also electromagnetic waves in other frequency bands is a reflective layer disposed on the entire surface of a frequency selective reflector. For example, Fig. 24 shows an example in which the reflective member 2 is a reflective layer 7. In Fig. 24, the reflective layer 7 is disposed on the entire surface of the frequency selective reflector 1.

[0186] The material for the reflective layer is not particularly limited as long as it is a material that can reflect electromagnetic waves in a specific frequency band, and examples of the material include metal materials and conductive materials such as ITO.

[0187] The thickness of the reflective layer is not particularly limited as long as it is a thickness that can reflect electromagnetic waves in a specific frequency band, and may be set appropriately.

[0188] Furthermore, the reflective member that reflects only electromagnetic waves in a specific frequency band may be anything that has a wavelength selection function that reflects only electromagnetic waves in a specific frequency band, and an example of such a member is a frequency selective plate.

[0189] The frequency selective plate is the same as that described in the first embodiment. For example, Fig. 16(b) shows an example in which the reflecting member 2 is a frequency selective plate, and the reflecting member 2 has a dielectric substrate 4 and a plurality of reflecting elements 3 arranged on the surface of the dielectric substrate 4 facing the dielectric layer 5.

[0190] Moreover, the shape and configuration of the reflecting element may be the same as those described in the first embodiment.

[0191] Moreover, it is preferable that the frequency selective plate, i.e., the reflecting member, has a reflection phase control function for controlling the reflection phase of the electromagnetic wave. In such a reflecting member, the resonance frequency can be changed for each reflecting element by changing the size and shape of the reflecting element, and the reflection phase of the electromagnetic wave can be controlled. Therefore, when the frequency selective plate has a reflection phase control function, the reflection characteristics of the electromagnetic wave can be controlled by controlling the reflection phase distribution of the electromagnetic wave by the thickness of the dielectric layer and the size and shape of the reflecting element. Therefore, for example, the reflection characteristics in two orthogonal directions (for example, the x-axis direction and the y-axis direction) in the plane of the frequency selective reflecting plate can be designed individually by the frequency selective plate and the dielectric layer, and the desired reflection characteristics of the electromagnetic wave can be obtained while suppressing the thickness of the dielectric layer.

[0192] A general frequency selective surface can be used as a frequency selective surface with a reflection phase control function. In either case, it is possible to change the reflection phase of an electromagnetic wave by changing the size and shape of the reflecting element.

[0193] The different dimensions of the reflective elements are appropriately selected depending on the shape of the reflective elements.

[0194] (c) Controlling the direction of electromagnetic wave reflection In the frequency selective reflector of this embodiment, by changing the thickness of each cell region of the unit structure of the dielectric layer, the round trip optical path length in the dielectric layer can be changed for each cell region, and the relative reflection phase of the electromagnetic wave can be controlled. This makes it possible to control the reflection direction of the electromagnetic wave incident from a predetermined direction by adjusting the size and planar pattern of the unit structure of the dielectric layer, and the number and thickness of the cell regions of the unit structure of the dielectric layer.

[0195] Furthermore, when the reflective member is a frequency selective plate and also has a reflection phase control function, not only can the round-trip optical path length in the dielectric layer be changed for each cell region by changing the thickness of each cell region of the unit structure of the dielectric layer, but also the resonant frequency for each reflection element can be changed by changing the dimensions and shape of the reflection elements of the reflective member, thereby controlling the reflection phase of the electromagnetic wave, thereby expanding the design freedom for controlling the reflection characteristics.

[0196] In this case, it is possible to separate the reflection control direction in the reflecting member from the reflection control direction in the dielectric layer, and perform two-dimensional reflection direction control with the entire frequency selective reflector. In addition, when the reflection control directions in the reflecting member and the dielectric layer are overlapped, for example, a reflection phase distribution that reflects in a certain direction can be realized by the reflecting member, and further fine-tuned by the dielectric layer. In this case, there is an advantage that the thickness of the dielectric layer can be made thin.

[0197] As an arrangement of the thickness distribution of the dielectric layer and the size distribution of the reflecting elements of the reflecting member, for example, as shown in Figures 25(a) and (b), the dielectric layer 5 and the reflecting member 2 can be arranged so that the thickness of the cell regions 11a to 11f of the unit structure 10 of the dielectric layer 5 increases as the size of the reflecting elements 3 of the reflecting member 2 increases. In such an embodiment, the thickness of the dielectric layer can be suppressed. As a result, the dielectric layer becomes thinner, so that the weight and cost of the frequency selective reflector can be reduced, and even if the reflection angle increases, the reflected wave is less likely to hit the dielectric layer.

[0198] In addition, the thickness distribution of the dielectric layer and the dimensional distribution of the reflective elements of the reflective member may be arranged, for example, as shown in Figures 26(a) and (b), such that the dimensions of the reflective elements 3 of the reflective member 2 increase along direction D4, and the thicknesses of the cell regions 11a to 11f of the unit structure 10 of the dielectric layer 5 increase along direction D3 perpendicular to direction D4.

[0199] In Fig. 26, since the dimensions of the reflecting elements are different in one cell region, the relative reflection phase of the electromagnetic wave in one cell region will be partially different depending on the dimensions of the reflecting elements. Even in such a case, when cut in the specified direction D3 in which the thickness increases, each point will be on the same line in the graph described above.

[0200] In addition, in the case of a specification in which the reflective member and the dielectric layer are designed separately and then combined, the reflection direction of the electromagnetic wave can be fine-tuned by rotating the dielectric layer in-plane relative to the reflective member around the normal direction as an axis to adjust the arrangement direction of the cell regions of the unit structure of the dielectric layer relative to the reflective member.

[0201] In addition, in the unit structure of the dielectric layer, the reflection characteristics can be controlled by adjusting the length of the unit structure in a predetermined direction in which the thickness increases. For example, the reflection angle of the electromagnetic wave can be increased by shortening the length of the unit structure in the predetermined direction in which the thickness increases. On the other hand, the reflection angle of the electromagnetic wave can be decreased by lengthening the length of the unit structure in the predetermined direction in which the thickness increases.

[0202] In addition, in the unit structure of the dielectric layer, the length of the unit structure in a predetermined direction in which the thickness increases refers to the length of the unit structure in the predetermined direction when the unit structure of the dielectric layer has a thickness distribution in which the thickness increases in the predetermined direction. For example, in Fig. 24, the thickness of the unit structure 10 of the dielectric layer 5 increases in the predetermined direction D3, and the length of the unit structure 10 in the predetermined direction D3 is L.

[0203] As described above, the in-plane arrangement of the concave-convex structure of the dielectric layer that realizes the in-plane distribution design of the reflection phase in the frequency selective reflector does not need to have a fixed positional relationship with the in-plane arrangement of the reflection elements of the reflecting member, and the reflection characteristics are not significantly affected even if the concave-convex structure of the dielectric layer is shifted from the in-plane arrangement of the reflection elements. Therefore, when the reflecting member is a frequency selective plate and a member having a reflection phase control function, the dielectric layer and the reflecting member can be designed independently.

[0204] (d) Other configurations The frequency selective reflector of this embodiment may have other configurations as necessary in addition to the above-mentioned reflecting member and dielectric layer.

[0205] (i) Adhesive layer The frequency selective reflector of this embodiment may have an adhesive layer between the reflecting member and the dielectric layer. The adhesive layer can adhere the reflecting member and the dielectric layer. In addition, when the reflecting member is a member in which a plurality of reflecting elements are arranged, the adhesive layer can flatten the unevenness caused by the reflecting elements, and can suppress the influence of the unevenness caused by the reflecting elements when the dielectric layer is laminated on the reflecting member. For example, in FIG. 16(b), an adhesive layer 6 is disposed between the reflecting member 2 and the dielectric layer 5.

[0206] For example, an adhesive or a pressure-sensitive adhesive can be used for the adhesive layer, and can be appropriately selected from known adhesives and pressure-sensitive adhesives. In this case, the adhesive or pressure-sensitive adhesive must be non-conductive. In addition, when the adhesive or pressure-sensitive adhesive is liquid, it is preferable that it can be spread evenly and has a fluidity sufficient to remove trapped air bubbles. In addition, when the adhesive or pressure-sensitive adhesive is in the form of a sheet, it is preferable that it has a uniform thickness and has a flexibility sufficient to follow the unevenness of the lamination interface and suppress the trapping of air bubbles.

[0207] The thickness of the adhesive layer is preferably uniform and is a thickness that can obtain a desired adhesive force. Furthermore, when the reflective member is a member in which a plurality of reflective elements are arranged, the thickness of the adhesive layer is preferably equal to or greater than the thickness of the reflective elements from the viewpoint of flattening. When the adhesive layer is thicker than the thickness of the reflective elements, the reflective elements are embedded in the adhesive layer. Furthermore, the thickness of the adhesive layer is preferably sufficiently smaller than the effective wavelength of the target electromagnetic wave, and the effective wavelength of the electromagnetic wave is set to λ g In this case, specifically, 0.01λ g It is preferable that:

[0208] (ii) Space The frequency selective reflector of this embodiment may have a space between the reflecting member and the dielectric layer. For example, in FIG. 27, a space 8 is provided between the reflecting member 2 and the dielectric layer 5.

[0209] When a space is provided between the reflecting member and the dielectric layer, the distance between the reflecting member and the dielectric layer is preferably constant, so that the optical path length in the space can be made uniform.

[0210] (iii) Cover member The frequency selective reflector of this embodiment may have a cover member on the surface of the dielectric layer opposite to the reflecting member. The cover member can protect the dielectric layer. The cover member can also provide a design.

[0211] (iv) Ground layer The frequency selective reflector of this embodiment may have a ground layer on the surface of the reflector opposite to the dielectric layer. The ground layer can block interference with an object on the back surface of the frequency selective reflector and suppress noise generation. The ground layer can also be a part of the reflector that does not have wavelength selectivity. The ground layer can be a conductive layer of a metal plate, a metal mesh, or an ITO film.

[0212] (v) Flattening layer The frequency selective reflector of this embodiment may have a planarization layer between the reflecting member and the dielectric layer. When the reflecting member is a member in which a plurality of reflecting elements are arranged, the planarization layer can planarize the unevenness caused by the reflecting elements, and can suppress the influence of the unevenness caused by the reflecting elements when the dielectric layer is laminated on the reflecting member. The planarization layer referred to here refers to a layer disposed separately from the adhesive layer, and can be exemplified by an ionizing radiation cured resin layer disposed in a state in which the reflecting elements are embedded. In addition, when a space is provided between the reflecting member and the dielectric layer, the planarization layer may have a function of protecting the reflecting elements.

[0213] (vi) Fixed layer When the frequency selective reflector of this embodiment is used by attaching it to a wall or the like, a fixing layer having a mechanism for attaching the frequency selective reflector may be disposed on the surface of the reflector opposite to the dielectric layer. In addition, in order to suppress interference between the fixing layer and the reflector and the dielectric layer, a metal layer may be disposed between the fixing layer and the reflector, or the fixing layer may also serve as the metal layer. In addition, when the frequency selective reflector of this embodiment is attached to a wall or the like, the fixing layer may have a mechanism for varying the angle of the normal direction of the frequency selective reflector so that the deviation between the designed incident direction and reflection direction of the electromagnetic wave and the actual incident direction and reflection direction of the electromagnetic wave can be corrected.

[0214] (vii) Antireflection layer In the case of high frequencies, the influence of reflection at the interface of the dielectric layer may be considered, so in the frequency selective reflector of this embodiment, an antireflection layer may be disposed at the interface between the dielectric layer and air, if necessary. The antireflection layer may have, for example, a multi-layer structure with different dielectric constants, or may have a concave-convex structure smaller than the effective wavelength of the electromagnetic wave.

[0215] (3) Other aspects of frequency selective reflectors The frequency selective reflector of this embodiment may be a variable frequency selective reflector that controls the reflection phase of the electromagnetic wave by electrical control or mechanical control, thereby varying the reflection direction of the electromagnetic wave, as described above. This embodiment can be realized even in the case of such a variable frequency selective reflector. Known variable frequency selective reflectors can be used.

[0216] 3. Other points about frequency selective reflectors The size of the frequency selective reflector of this embodiment is appropriately selected depending on, for example, the reflection characteristics of the desired frequency selective reflector as a whole, the reflection characteristics of each divided region, the arrangement of each divided region, the planar shape of each divided region, the size of each divided region, etc.

[0217] Specifically, the size of the entire frequency selective reflector can be designed as follows: First, when the frequency selective reflector does not have a divided region, i.e., has only a main region, the physical area S0 of the frequency selective reflector, i.e., the area capable of reflecting the electromagnetic waves required for the desired reception area, is calculated from the radar cross section RCS of the frequency selective reflector capable of reflecting the electromagnetic waves required for the desired reception area by the following formula (3).

[0218]

number

[0219] In the above formula (3), S0 is the physical area (m 2 ), RCS is the radar cross section of the plate (m 2 ), λ is the wavelength of the electromagnetic wave (m), and k is the power reflectance of the frequency selective reflector when it does not have a dividing region (for an ideal metal, it is 1).

[0220] Next, when the frequency selective reflector does not have a divided region, the full width at half maximum (FWHM) of the reflected beam profile by the frequency selective reflector is calculated by the following formula (2). FWHM[rad]=λ / (0.8×D)~λ / (0.6×D) (2) In the above formula (2), λ is the wavelength of the electromagnetic wave, and D is the diameter of the frequency selective reflector. In addition, when the diameter D of the frequency selective reflector in the above formula (2) is rewritten using the physical area S0 of the frequency selective reflector, the following formula (4) is obtained.

[0221]

number

[0222] When a frequency selective reflector does not have a divided region, i.e., when it has only a main region, and the half-width FWHM of the reflected beam profile by the frequency selective reflector does not satisfy the desired reception range, the frequency selective reflector is designed to be composed of multiple divided regions, i.e., by adding multiple sub-regions to the main region.

[0223] Also, the full width at half maximum (FWHM) of the reflected beam profile corresponds to the solid angle Sr of the reflected beam. For example, as shown in Fig. 28(a), if the reflected beam by the entire frequency selective reflector 1 spreads in a cone shape at ±θr with respect to the reflection direction vector r0 of the electromagnetic wave in the main region, the solid angle Sr of the cone that spreads at ±θs from the reflection direction vector of the electromagnetic wave in the main region can be calculated by the following formula (5). Sr = 2π(1-cosθs) (5) In addition, as shown in FIG. 28(b), when the reflected beam by the entire frequency selective reflector 1 spreads in a cone shape with respect to the reflection direction vector r0 of the electromagnetic wave in the main region, if the reflected beam includes an electromagnetic wave reflection direction vector whose reflection intensity is half or more of the reflection intensity of the electromagnetic wave reflection direction vector r0 in the main region, the solid angle Sr of the cone is HM is calculated by the following formula (6). Sr HM =2π(1-cosθ HM ) (6) In the above formula (6), θ HMrepresents the angle between the reflection direction vector r0 of the electromagnetic wave in the main region and the reflection direction vector of the electromagnetic wave at which the reflection intensity of the reflection direction vector r0 of the electromagnetic wave in the main region is half in the beam reflected by the entire frequency selective reflector, and is expressed by the following equation (7). θ HM =FWHM / 2 (7)

[0224] Therefore, it is preferable that the area S1 of the frequency selective reflector of this embodiment satisfies the following formula (1). S1 ≧ S0 × Sr1 / Sr0 (1) In the above formula (1), S1 is the area (m 2 ), Sr1 is the solid angle of the reflected beam that meets the desired reception range of the electromagnetic wave, and S0 is the area (m 2 ), and Sr0 represents the solid angle of the reflected beam by a frequency selective reflector having an area of ​​S0 when the frequency selective reflector does not have the above-mentioned divided regions.

[0225] Furthermore, when the frequency selective reflector does not have the above-mentioned divided region, if the half-width FWHM of the reflected beam profile by a frequency selective reflector having an area S0 does not satisfy the desired reception range, i.e., when the frequency selective reflector does not have the above-mentioned divided region, if the solid angle Sr0 of the reflected beam by a frequency selective reflector having an area S0 does not satisfy the desired reception range, when the area S1 of the frequency selective reflector of this embodiment is designed to be n times S0, it is preferable to satisfy the following formula (8-1), it is more preferable to satisfy the following formula (8-2), and it is even more preferable to satisfy the following formula (8-3). Sr0×n / Sr1≧1 (8-1) Sr0×n / Sr1≧1.5 (8-2) Sr0×n / Sr1≧2 (8-3)

[0226] The frequency selective reflector of this embodiment can be applied to both plane and spherical waves. For example, the frequency selective reflector of this embodiment can reflect an incident plane wave as a plane wave, an incident spherical wave as a spherical wave, and an incident spherical wave as a plane wave.

[0227] The frequency selective reflector of this embodiment reflects electromagnetic waves of a specific frequency band in a direction different from the regular reflection direction. The frequency band of the electromagnetic waves is preferably a frequency band equal to or higher than microwaves, which have a strong linearity. The frequency band of the electromagnetic waves is preferably, for example, 2.5 GHz or higher, more preferably 24 GHz or higher, and even more preferably 24 GHz or higher and 300 GHz or lower. If the frequency band of the electromagnetic waves is within the above range, the frequency selective reflector of this embodiment can be used in the fifth generation mobile communication system, so-called 5G.

[0228] The frequency selective reflector of this embodiment can be used, for example, as a frequency selective reflector for communications, and is particularly suitable as a frequency selective reflector for mobile communications.

[0229] II. Second embodiment The frequency selective reflector of this embodiment is a frequency selective reflector that reflects electromagnetic waves of a specific frequency band in a direction different from the direct reflection direction, and the entire surface of the frequency selective reflector is divided into a plurality of divided regions, and the reflection direction vector of the electromagnetic wave in each of the divided regions is different from one another, and the reflection direction vector of the electromagnetic wave in each of the divided regions is set to spread outward from the main reflection direction vector of the electromagnetic wave, which is derived from the sum of the reflection direction vectors of the electromagnetic wave in each of the divided regions.

[0230] Figures 29(a) to (d) are schematic plan views showing an example of a frequency selective reflector of this embodiment. As shown in Figures 29(a) to (d), the entire surface of the frequency selective reflector 1 is divided into a plurality of divided regions. In the example shown in Figures 29(a) to (d), the frequency selective reflector 1 has two divided regions A1 and A2.

[0231] 29(a) to (d) show an example of the reflection characteristics of each divided region of a frequency selective reflector. For example, as shown in FIG. 6, when the frequency selective reflector 1 is set vertically on the ground (XZ plane) and viewed from the electromagnetic wave reflecting side, the left corner is the origin, the horizontal direction is the x-axis, the vertical direction is the y-axis, and the normal direction to the reflecting side is the z-axis, the electromagnetic wave reflection direction vector d r The polar angle is defined as θ and the azimuth angle as φ.

[0232] When the main reflection direction vector of the electromagnetic wave is inclined from the divided area A1 to the divided area A2 side (φ=0° direction), as shown in FIG. 29(a), the polar angle of the main reflection direction vector of the electromagnetic wave is set to θ r , azimuth angle is φ r In the divided area A1, (θ r -α, φ r ), and in the divided area A2 (θ r +α, φ r )

[0233] The amount of displacement of the polar angle and azimuth angle of the reflection direction vector of the electromagnetic wave in each of these divided regions depends on the direction in which the main reflection direction vector of the electromagnetic wave is tilted with respect to the surface of the frequency selective reflector. Figure 29(b) is an example in which the main reflection direction vector of the electromagnetic wave is tilted from the divided region A2 toward the divided region A1 side (φ=180°). Figure 29(c) is an example in which the main reflection direction vector of the electromagnetic wave is tilted from the divided regions A1 and A2 toward the upper side of the paper (φ=90°). Figure 29(d) is an example in which the main reflection direction vector of the electromagnetic wave is tilted from the divided regions A1 and A2 toward the lower side of the paper (φ=270°).

[0234] Note that α and β are positive numbers. The values ​​and signs of α and β are merely guidelines when the reflection direction vector of the electromagnetic wave is expressed in polar coordinates, and they change depending on the settings of the main reflection direction vector of the electromagnetic wave and the spread of the reflection direction vector of the electromagnetic wave over the entire frequency selective reflector.

[0235] Essentially, the reflection direction vector of the electromagnetic wave in each divided area is set to spread outward from the main reflection direction vector of the electromagnetic wave as the center, and, as described below, it is preferable that the angle θds between the reflection direction vectors of the electromagnetic wave between adjacent divided areas is set to be within a predetermined range.

[0236] 29(a) to (d), the reflected beams from the divided regions A1 to A2 overlap each other, forming one main lobe (main beam) in the reflected beam profile from the entire frequency selective reflector 1, and it is possible to widen the beam width of the reflected wave from the entire frequency selective reflector 1. This makes it possible to widen the area irradiated with the reflected beam from the frequency selective reflector.

[0237] In addition, in the case where the frequency selective reflector does not have the divided regions as in the conventional case, but has only the main region as in the first embodiment, for example, increasing the size of the frequency selective reflector increases the gain in principle, and the reflected beam by the frequency selective reflector becomes sharper. In this case, the beam width of the reflected wave by the frequency selective reflector becomes narrower, and the area irradiated by the reflected beam by the frequency selective reflector becomes narrower.

[0238] In this embodiment, the frequency selective reflector is divided into a plurality of divided regions, and the size of each divided region is small, so that the gain is somewhat reduced, but the beam width of the reflected wave from each divided region is widened. Furthermore, the reflection direction vectors of the electromagnetic wave in each divided region are slightly different from each other, and the reflection direction vectors of the electromagnetic wave in each divided region are set to spread outward from the main reflection direction vector of the electromagnetic wave as the center, so that the reflected beams from each divided region overlap, and the beam width of the reflected wave from the entire frequency selective reflector can be widened. Therefore, it is possible to widen the area irradiated with the reflected beam from the frequency selective reflector.

[0239] Each component of the frequency selective reflector of this embodiment will be described below.

[0240] 1.Divided area The entire surface of the frequency selective reflector of this embodiment is divided into a plurality of divided regions.

[0241] The arrangement of each divided region is appropriately selected depending on the desired reflection characteristics of the entire frequency selective reflector, the reflection characteristics of each divided region, the planar shape of each divided region, and the like.

[0242] In particular, it is preferable that each divided region is arranged point-symmetrically with respect to the center of the frequency selective reflector. This makes it easier to widen the beam width of the reflected wave by the entire frequency selective reflector. For example, in Fig. 29(a)-(b), two divided regions A1-A2 are arranged point-symmetrically with respect to the center 100 of the frequency selective reflector 1. Also, for example, in Fig. 30(a), four divided regions A are arranged point-symmetrically with respect to the center 100 of the frequency selective reflector 1. In Fig. 30(b), 16 divided regions A are arranged point-symmetrically with respect to the center 100 of the frequency selective reflector 1. In Fig. 30(c), three divided regions A are arranged point-symmetrically with respect to the center 100 of the frequency selective reflector 1.

[0243] The planar shape of each divided region may be the same as that of the first embodiment.

[0244] The number of divided regions is multiple and is appropriately selected depending on the reflection characteristics of the desired frequency selective reflector as a whole, the reflection characteristics of each divided region, the arrangement of each divided region, the planar shape of each divided region, the size of each divided region, etc. When the size of the frequency selective reflector as a whole is constant, the more the number of divided regions, the smaller the size of the divided regions. When the size of the divided regions is reduced, the disturbance of the reflected beam profile caused by the frequency selective reflector as a whole is suppressed, and the side lobes in the reflected beam profile tend to be lower. In this case, a broad reflected beam can be stably obtained.

[0245] In this embodiment, the reflection direction vectors of the electromagnetic waves in the divided regions are different from each other. Specifically, it is sufficient that at least one of the polar angle and the azimuth angle of the reflection direction vector of the electromagnetic waves is different in each divided region.

[0246] In addition, it is preferable that the angle between the reflection direction vectors of the electromagnetic wave between adjacent divided regions is relatively small. In each divided region, the reflection direction vector of the electromagnetic wave changes gradually, which suppresses the disturbance of the reflected beam profile caused by the entire frequency selective reflector, and the side lobes in the reflected beam profile tend to be low. In this case, a broad reflected beam can be stably obtained.

[0247] Adjacent divided regions need only differ in at least one of the polar angle and the azimuth angle of the reflection direction vector of the electromagnetic wave.

[0248] The angle θds between the reflection direction vectors of the electromagnetic waves in adjacent divided regions can be the same as in the first embodiment.

[0249] Furthermore, among the multiple divided regions, the angles formed by the reflection direction vectors of the electromagnetic waves in adjacent divided regions may be the same or different, but are usually the same.

[0250] In this embodiment, the reflection direction vector of the electromagnetic wave in each divided region is set to expand outward from the main reflection direction vector of the electromagnetic wave, which is derived from the sum of the reflection direction vectors of the electromagnetic wave in each divided region. By setting the reflection direction vector of the electromagnetic wave in each divided region in this manner, the beam width of the reflected wave by the entire frequency selective reflector can be expanded.

[0251] The main reflection direction vector of the electromagnetic wave is derived from the sum of the reflection direction vectors of the electromagnetic wave in each divided region, and is the direction of the resultant vector of the unit vectors that represent the reflection direction of the electromagnetic wave in each divided region. In this embodiment, the main reflection direction vector of the electromagnetic wave reflected by the frequency selective reflector as a whole can be considered to be reflected from the center of the frequency selective reflector.

[0252] The reflection direction vector of each divided region within the plane of the frequency selective reflector may be set so that the reflection direction vector of the electromagnetic wave in each divided region spreads outward from the main reflection direction vector of the electromagnetic wave. The reflection direction vector of the electromagnetic wave in each divided region can be set by the polar angle and azimuth angle of the reflection direction vector of the electromagnetic wave. It is preferable that the angle between the reflection direction vectors of the electromagnetic wave between adjacent divided regions is gradually changed within the range of the angle between the reflection direction vectors of the electromagnetic wave between the adjacent divided regions described above.

[0253] In addition, in this embodiment, in a graph in which the horizontal axis represents the deviation angle from the main reflection direction vector of the electromagnetic wave and the vertical axis represents the reflection intensity of the electromagnetic wave from the frequency selective reflector, the half-width of the reflected beam profile can be the same as in the first embodiment described above.

[0254] The size of each divided region is appropriately selected depending on, for example, the reflection characteristics of the entire frequency selective reflector, the reflection characteristics of each divided region, the arrangement of each divided region, the planar shape of each divided region, the number of divided regions, etc. The size of each divided region may be 1 / 2 or less of the size of the frequency selective reflector. Other aspects of the size of each divided region may be the same as those of the first embodiment.

[0255] 2. Structure of frequency selective reflector The configuration of the frequency selective reflector of this embodiment can be the same as that of the first embodiment.

[0256] (1) First embodiment of frequency selective reflector A first aspect of the frequency selective reflector of this embodiment is similar to the first aspect of the frequency selective reflector of the above-mentioned first embodiment.

[0257] In this embodiment, the reflection direction vector of the electromagnetic wave is determined in the same manner as in the first embodiment of the frequency selective reflector of the first embodiment described above.

[0258] Therefore, in this embodiment, the entire surface of the frequency selective reflector is divided into a plurality of divided regions, the frequency selective reflector has a reflecting member that reflects the electromagnetic wave, the reflecting member has a reflection phase control function that controls the reflection phase of the electromagnetic wave, the reflecting member has a plurality of unit structures arranged therein, each unit structure having a plurality of reflecting elements with different dimensions, and each divided area has at least one unit structure; Assuming a three-dimensional orthogonal coordinate system in which the surface of the frequency selective reflector is the xy plane and the normal direction of the surface of the frequency selective reflector is the z axis, and assuming that in the three-dimensional orthogonal coordinate system, the start point of the direction in which the dimensions of the reflecting elements of the unit structure on the xy plane increase is the right-angled apex, and that a right-angled triangle has adjacent sides that are the length of the direction in which the dimensions of the reflecting elements of the unit structure on the xy plane increase and the wavelength of the electromagnetic wave parallel to the z axis, The normal directions of the hypotenuse of the right triangle in each of the divided regions are different from each other, and in other words, the normal directions of the hypotenuse of the right triangle in each of the divided regions are set to extend outward from the main reflection direction vector of the electromagnetic wave, which is derived from the sum of the vectors of the normal directions of the hypotenuse of the right triangle in each of the divided regions.

[0259] In addition, the length of the vector in the normal direction of the hypotenuse of the right triangle in each divided area is defined as a unit vector, and the direction of the main reflection vector of the electromagnetic wave is obtained by the sum of these unit vectors.)

[0260] (2) Second embodiment of frequency selective reflector The second aspect of the frequency selective reflector of this embodiment is similar to the second aspect of the frequency selective reflector of the above-mentioned first embodiment.

[0261] In this embodiment, the reflection direction vector of the electromagnetic wave is determined in the same manner as in the first embodiment of the frequency selective reflector of the first embodiment described above.

[0262] Therefore, in this embodiment, the entire surface of the frequency selective reflector is divided into a plurality of divided regions, the frequency selective reflector includes a reflecting member that reflects the electromagnetic wave, and a dielectric layer that is disposed on an incident side of the electromagnetic wave with respect to the reflecting member, has a concavo-convex structure in which a plurality of unit structures having a thickness distribution in which the thickness increases in a predetermined direction are disposed, and transmits the electromagnetic wave, the unit structure of the dielectric layer has a plurality of cell regions having different thicknesses, and each of the divided regions has at least one unit structure, Assuming a three-dimensional orthogonal coordinate system in which the surface of the frequency selective reflector is the xy plane and the normal direction to the surface of the frequency selective reflector is the z axis, and assuming that in the three-dimensional orthogonal coordinate system, the start point of the direction in which the thickness of the cell region of the unit structure on the xy plane increases is a right-angled apex, and the adjacent sides are the length of the direction in which the thickness of the cell region of the unit structure on the xy plane increases and the wavelength of the electromagnetic wave parallel to the z axis, The normal directions of the hypotenuse of the right triangle in each of the divided regions are different from each other, and in other words, the normal directions of the hypotenuse of the right triangle in each of the divided regions are set to extend outward from the main reflection direction vector of the electromagnetic wave, which is derived from the sum of the vectors of the normal directions of the hypotenuse of the right triangle in each of the divided regions.

[0263] The length of the vector in the normal direction of the hypotenuse of the right triangle in each divided region is taken as a unit vector, and the direction of the main reflection vector of the electromagnetic wave is found by the sum of these unit vectors.

[0264] 3. Other points about frequency selective reflectors Other aspects of the frequency selective reflector of this embodiment can be similar to those of the first embodiment.

[0265] III. Third embodiment The frequency selective reflector of this embodiment is a frequency selective reflector that reflects electromagnetic waves of a specific frequency band in a direction different from the direct reflection direction, and the entire surface of the frequency selective reflector is divided into a plurality of divided regions, and the plurality of divided regions have a main region which is a divided region located at the center of the frequency selective reflector, and a plurality of sub-regions which are divided regions other than the main region, and the plurality of sub-regions are arranged around the main region, and the reflection direction vectors of the electromagnetic waves in each of the divided regions are different from each other, and the reflection direction vectors of the electromagnetic waves in each of the sub-regions are set to converge inward with the reflection direction vector of the electromagnetic wave in the main region as the center.

[0266] In this embodiment, as in the first embodiment, the reflected beam from the main region overlaps with the reflected beam from each sub-region, forming one main lobe (main beam) in the reflected beam profile of the entire frequency selective reflector. On the other hand, in this embodiment, contrary to the first embodiment, the reflection direction vector of the electromagnetic wave in each sub-region is set to converge inward with the reflection direction vector of the electromagnetic wave in the main region as the center, so that the reflected wave from the entire frequency selective reflector can be concentrated at a predetermined distance and in a predetermined direction. That is, in this embodiment, contrary to the first embodiment, the beam width of the reflected wave from the entire frequency selective reflector can be narrowed, and thus the area irradiated with the reflected beam from the frequency selective reflector can be narrowed. Such a frequency selective reflector can be applied, for example, to a case where the reflected electromagnetic wave is concentrated and delivered to a repeater or CPE (Customer Premises Equipment), etc.

[0267] The frequency selective reflector of this embodiment may be similar to that of the first embodiment described above, except that the reflection direction vector of the electromagnetic wave in each sub-region is set to converge inward around the reflection direction vector of the electromagnetic wave in the main region.

[0268] (First embodiment of frequency selective reflector) A first aspect of the frequency selective reflector of this embodiment is similar to the first aspect of the frequency selective reflector of the above-mentioned first embodiment.

[0269] In this embodiment, the reflection direction vector of the electromagnetic wave is determined in the same manner as in the first embodiment of the frequency selective reflector of the first embodiment described above.

[0270] Therefore, in this aspect, the entire surface of the frequency selective reflector is divided into a plurality of divided regions, and the plurality of divided regions include a main region which is a divided region located at the center of the frequency selective reflector, and a plurality of sub-regions which are divided regions other than the main region, and the plurality of sub-regions are arranged around the main region, the frequency selective reflector has a reflecting member that reflects the electromagnetic wave, the reflecting member has a reflection phase control function that controls the reflection phase of the electromagnetic wave, the reflecting member has a plurality of unit structures arranged therein, each unit structure having a plurality of reflecting elements with different dimensions, and each divided area has at least one unit structure; Assuming a three-dimensional orthogonal coordinate system in which the surface of the frequency selective reflector is the xy plane and the normal direction of the surface of the frequency selective reflector is the z axis, and assuming that in the three-dimensional orthogonal coordinate system, the start point of the direction in which the size of the reflecting element of the unit structure on the xy plane increases is a right-angled apex, and the adjacent sides are the length of the direction in which the size of the reflecting element of the unit structure on the xy plane increases and the wavelength of the electromagnetic wave parallel to the z axis, In other words, the normal directions of the hypotenuse of the right triangle in each of the divided regions are different from each other, and the normal directions of the hypotenuse of the right triangle in each of the sub-regions are set to converge inward around the normal direction of the hypotenuse of the right triangle in the main region.

[0271] (Second embodiment of frequency selective reflector) The second aspect of the frequency selective reflector of this embodiment is similar to the second aspect of the frequency selective reflector of the above-mentioned first embodiment.

[0272] In this embodiment, the reflection direction vector of the electromagnetic wave is determined in the same manner as in the first embodiment of the frequency selective reflector of the first embodiment described above.

[0273] Therefore, in this aspect, the entire surface of the frequency selective reflector is divided into a plurality of divided regions, and the plurality of divided regions include a main region which is a divided region located at the center of the frequency selective reflector, and a plurality of sub-regions which are divided regions other than the main region, and the plurality of sub-regions are arranged around the main region, the frequency selective reflector includes a reflecting member that reflects the electromagnetic wave, and a dielectric layer that is disposed on an incident side of the electromagnetic wave with respect to the reflecting member, has a concavo-convex structure in which a plurality of unit structures having a thickness distribution in which the thickness increases in a predetermined direction are disposed, and transmits the electromagnetic wave, the unit structure of the dielectric layer has a plurality of cell regions having different thicknesses, and each of the divided regions has at least one unit structure, Assuming a three-dimensional orthogonal coordinate system in which the surface of the frequency selective reflector is the xy plane and the normal direction to the surface of the frequency selective reflector is the z axis, and assuming that in the three-dimensional orthogonal coordinate system, the start point of the direction in which the thickness of the cell region of the unit structure on the xy plane increases is a right-angled apex, and the adjacent sides are the length of the direction in which the thickness of the cell region of the unit structure on the xy plane increases and the wavelength of the electromagnetic wave parallel to the z axis, In other words, the normal directions of the hypotenuse of the right triangle in each of the divided regions are different from each other, and the normal directions of the hypotenuse of the right triangle in each of the sub-regions are set to converge inward around the normal direction of the hypotenuse of the right triangle in the main region.

[0274] (Modification) The reflection direction vector of the electromagnetic wave in each sub-region may be set so as to spread outward from the reflection direction vector of the electromagnetic wave in the main region in the horizontal direction, and to converge inward from the reflection direction vector of the electromagnetic wave in the main region in the vertical direction. Alternatively, the reflection direction vector of the electromagnetic wave in each sub-region may be set so as to spread outward from the reflection direction vector of the electromagnetic wave in the main region in the vertical direction, and to converge inward from the reflection direction vector of the electromagnetic wave in the main region in the horizontal direction. By setting the reflection direction vector of the electromagnetic wave in each divided region in this manner, it is possible to arbitrarily control the area onto which the reflected beam is irradiated.

[0275] IV. Fourth embodiment The frequency selective reflector of this embodiment is a frequency selective reflector that reflects electromagnetic waves of a specific frequency band in a direction different from the direct reflection direction, and the entire surface of the frequency selective reflector is divided into a plurality of divided regions, and the reflection direction vector of the electromagnetic wave in each of the divided regions is different from one another, and the reflection direction vector of the electromagnetic wave in each of the divided regions is set to converge inward around the main reflection direction vector of the electromagnetic wave, which is derived from the sum of the reflection direction vectors of the electromagnetic wave in each of the divided regions.

[0276] In this embodiment, as in the second embodiment, the reflected beams from each divided region overlap each other, forming one main lobe (main beam) in the reflected beam profile from the entire frequency selective reflector. On the other hand, in this embodiment, contrary to the second embodiment, the reflection direction vector of the electromagnetic wave in each divided region is set to converge inward with the main reflection direction vector of the electromagnetic wave as the center, so that the reflected wave from the entire frequency selective reflector can be concentrated at a predetermined distance and in a predetermined direction. That is, in this embodiment, contrary to the second embodiment, the beam width of the reflected wave from the entire frequency selective reflector can be narrowed. This makes it possible to narrow the area where the reflected beam from the frequency selective reflector is irradiated. Such a frequency selective reflector can be applied, for example, to cases where the reflected electromagnetic wave is concentrated and delivered to a repeater or CPE (Customer Premises Equipment), etc.

[0277] The frequency selective reflector of this embodiment can be similar to the second embodiment described above, except that the reflection direction vector of the electromagnetic wave in each divided region is set to converge inward around the main reflection direction vector of the electromagnetic wave.

[0278] (First embodiment of frequency selective reflector) A first aspect of the frequency selective reflector of this embodiment is similar to the first aspect of the frequency selective reflector of the above-mentioned first embodiment.

[0279] In this embodiment, the reflection direction vector of the electromagnetic wave is determined in the same manner as in the first embodiment of the frequency selective reflector of the first embodiment described above.

[0280] Therefore, in this embodiment, the entire surface of the frequency selective reflector is divided into a plurality of divided regions, the frequency selective reflector has a reflecting member that reflects the electromagnetic wave, the reflecting member has a reflection phase control function that controls the reflection phase of the electromagnetic wave, the reflecting member has a plurality of unit structures arranged therein, each unit structure having a plurality of reflecting elements with different dimensions, and each divided area has at least one unit structure; Assuming a three-dimensional orthogonal coordinate system in which the surface of the frequency selective reflector is the xy plane and the normal direction of the surface of the frequency selective reflector is the z axis, and assuming that in the three-dimensional orthogonal coordinate system, the start point of the direction in which the size of the reflecting element of the unit structure on the xy plane increases is a right-angled apex, and the adjacent sides are the length of the direction in which the size of the reflecting element of the unit structure on the xy plane increases and the wavelength of the electromagnetic wave parallel to the z axis, The normal directions of the hypotenuse of the right triangle in each of the divided regions are different from each other, and in other words, the normal directions of the hypotenuse of the right triangle in each of the divided regions are set so as to converge inward around the main reflection direction vector of the electromagnetic wave, which is derived from the sum of the vectors of the normal directions of the hypotenuse of the right triangle in each of the divided regions.

[0281] The length of the vector in the normal direction of the hypotenuse of the right triangle in each divided region is taken as a unit vector, and the direction of the main reflection vector of the electromagnetic wave is found by the sum of these unit vectors.

[0282] (Second embodiment of frequency selective reflector) The second aspect of the frequency selective reflector of this embodiment is similar to the second aspect of the frequency selective reflector of the above-mentioned first embodiment.

[0283] In this embodiment, the reflection direction vector of the electromagnetic wave is determined in the same manner as in the first embodiment of the frequency selective reflector of the first embodiment described above.

[0284] Therefore, in this embodiment, the entire surface of the frequency selective reflector is divided into a plurality of divided regions, the frequency selective reflector includes a reflecting member that reflects the electromagnetic wave, and a dielectric layer that is disposed on an incident side of the electromagnetic wave with respect to the reflecting member, has a concavo-convex structure in which a plurality of unit structures having a thickness distribution in which the thickness increases in a predetermined direction are disposed, and transmits the electromagnetic wave, the unit structure of the dielectric layer has a plurality of cell regions having different thicknesses, and each of the divided regions has at least one unit structure, Assuming a three-dimensional orthogonal coordinate system in which the surface of the frequency selective reflector is the xy plane and the normal direction to the surface of the frequency selective reflector is the z axis, and assuming that in the three-dimensional orthogonal coordinate system, the start point of the direction in which the thickness of the cell region of the unit structure on the xy plane increases is a right-angled apex, and the adjacent sides are the length of the direction in which the thickness of the cell region of the unit structure on the xy plane increases and the wavelength of the electromagnetic wave parallel to the z axis, The normal directions of the hypotenuse of the right triangle in each of the divided regions are different from each other, and in other words, the normal directions of the hypotenuse of the right triangle in each of the divided regions are set so as to converge inward around the main reflection direction vector of the electromagnetic wave, which is derived from the sum of the vectors of the normal directions of the hypotenuse of the right triangle in each of the divided regions.

[0285] The length of the vector in the normal direction of the hypotenuse of the right triangle in each divided region is taken as a unit vector, and the direction of the main reflection vector of the electromagnetic wave is found by the sum of these unit vectors.

[0286] (Modification) The reflection direction vector of the electromagnetic wave in each divided region may be set so as to spread outward from the main reflection direction vector of the electromagnetic wave as the center in the horizontal direction, and so as to converge inward from the main reflection direction vector of the electromagnetic wave as the center in the vertical direction. Alternatively, the reflection direction vector of the electromagnetic wave in each sub-region may be set so as to spread outward from the main reflection direction vector of the electromagnetic wave as the center in the vertical direction, and so as to converge inward from the main reflection direction vector of the electromagnetic wave as the center in the horizontal direction. By setting the reflection direction vector of the electromagnetic wave in each divided region in this way, it is possible to arbitrarily control the area irradiated with the reflected beam.

[0287] V. Fifth embodiment The frequency reflector of this embodiment is a frequency selective reflector that reflects electromagnetic waves of a specific frequency band in a direction different from the direct reflection direction, and has a plurality of cell regions with different reflection phases of the electromagnetic waves arranged repeatedly. When the reflection phase of the electromagnetic wave in the cell region where the lead of the reflection phase of the electromagnetic wave is the greatest is used as a reference and the relative reflection phase of the electromagnetic wave in each cell region is set to greater than -360 degrees and less than 0 degrees, the boundary portion where the relative reflection phase of the electromagnetic wave, which gradually decreases, suddenly increases is not branched but is a continuous curve.

[0288] Fig. 31 is a schematic plan view illustrating the cell region in the frequency selective reflector of this embodiment. The frequency selective reflector shown in Fig. 31 has nine types of cell regions with different reflection phases of electromagnetic waves. In the nine types of cell regions, the reflection phase of the electromagnetic wave in the cell region with the largest advance in the reflection phase of the electromagnetic wave is taken as a reference, and the relative reflection phase of the electromagnetic wave in each cell region is set to more than -360 degrees and 0 degrees or less, and the relative reflection phase of the electromagnetic wave in each cell region is, for example, 0 degrees, -40 degrees, -80 degrees, -120 degrees, -160 degrees, -200 degrees, -240 degrees, -280 degrees, and -320 degrees in descending order. In Fig. 31, the cell regions are numbered 0, 1, 2, 3, 4, 5, 6, 7, and 8 in descending order of the relative reflection phase of the electromagnetic wave in each cell region.

[0289] In Fig. 31, the relative reflection phase of the electromagnetic wave in each cell area repeatedly increases and decreases in a predetermined direction D3. In Fig. 31, the boundary parts where the gradually decreasing relative reflection phase of the electromagnetic wave suddenly increases are the part where the relative reflection phase of the electromagnetic wave increases from -320 degrees to 0 degrees, and the part where the relative reflection phase of the electromagnetic wave increases from -320 degrees to -40 degrees. In other words, the boundary parts where the gradually decreasing relative reflection phase of the electromagnetic wave suddenly increases are the boundary parts between cell area (8) and cell area (0), and the boundary parts between cell area (8) and cell area (1). These boundary parts are indicated by thick lines. The boundary parts are not branched but are continuous curved lines.

[0290] Here, as in the frequency selective reflectors of the first to fourth embodiments described above, when the entire surface of the frequency selective reflector is divided into a plurality of divided regions and the reflection direction vectors of the electromagnetic waves in each divided region are different from each other, for example, it is considered to design the reflection characteristics of each divided region and combine all the divided regions. In this case, the relative reflection phase of the electromagnetic waves repeatedly increases and decreases in each divided region. Meanwhile, at the boundary between adjacent divided regions, there may be a location where the relative reflection phase of the electromagnetic waves changes discontinuously. In this case, the boundary portion where the relative reflection phase of the electromagnetic waves, which gradually decreases, suddenly increases, branches or is interrupted. This causes a decrease in the performance of the frequency selective reflector.

[0291] In contrast, in this embodiment, the boundary portion where the gradually decreasing relative reflection phase of the electromagnetic wave suddenly increases is not branched but is a continuous curve, eliminating the boundary between adjacent divided regions as described above, thereby improving the performance of the frequency selective reflector.

[0292] In this embodiment, rather than designing the reflection characteristics for each divided region, the reflection characteristics are designed for the entire frequency selective reflector, thereby eliminating the boundaries between adjacent divided regions as described above, and making it possible to make the boundary portion where the relative reflection phase of the electromagnetic wave, which gradually decreases, suddenly increases into a continuous curve without branching.

[0293] Furthermore, in this embodiment, when the entire surface of the frequency selective reflector is divided into a plurality of virtual divided regions and the reflection direction vector of the electromagnetic wave in each virtual divided region is set in the same manner as in the frequency selective reflectors of the first to fourth embodiments described above, the boundary portion where the relative reflection phase of the electromagnetic wave, which gradually decreases, suddenly increases is not branched but is a continuous curve, so that the change in the reflection direction vector of the electromagnetic wave can be made gradual over the entire surface of the frequency selective reflector.

[0294] The virtual divided area is, for example, an area showing a reflection direction vector of one electromagnetic wave. Gently changing the reflection direction vector of the electromagnetic wave on the entire surface of the frequency selective reflector is suitable for adjusting the spread of the electromagnetic wave, such as a so-called spherical wave or a plane wave. For this purpose, it is necessary to increase the number of virtual divided areas. That is, it is necessary to reduce the size of the virtual divided area. At this time, if the size of the virtual divided area is reduced to the limit, the size of the divided area can be reduced to the size of the cell area. When the size of the virtual divided area is set to the size of the cell area, the reflection direction vector of the electromagnetic wave in one virtual divided area is determined based on the relationship with other virtual divided areas adjacent to the periphery of the one virtual divided area. Furthermore, gently changing the reflection direction vector of the electromagnetic wave on the entire surface of the frequency selective reflector is equivalent to making the reflection wave surface determined from the in-plane distribution of the relative reflection phase of the electromagnetic wave smooth. For this purpose, it is necessary to set the boundary part where the relative reflection phase of the electromagnetic wave, which gradually decreases, suddenly increases, to be a continuous curved shape without branching.

[0295] Each component of the frequency selective reflector of this embodiment will be described below.

[0296] 1. Cell Area In the frequency selective reflector of this embodiment, a plurality of cell regions with different reflection phases of electromagnetic waves are repeatedly arranged.

[0297] Note that "multiple cell regions with different reflection phases of electromagnetic waves are repeatedly arranged" means that the multiple cell regions are arranged so that the reflection phase of the electromagnetic waves in each cell region repeatedly increases and decreases, but the increase and decrease is not necessarily periodic. For example, as shown in Figures 31, 32(a) and 32(b), the cell regions appear to be roughly periodically arranged, but strictly speaking, they are not periodically arranged, and are repeatedly arranged according to the desired reflection characteristics.

[0298] In this embodiment, when the relative reflection phase of the electromagnetic wave in each cell region is set to greater than -360 degrees and less than 0 degrees based on the reflection phase of the electromagnetic wave in the cell region where the advance of the reflection phase of the electromagnetic wave is greatest, the boundary portion where the relative reflection phase of the electromagnetic wave, which gradually decreases, suddenly increases is not branched but is a continuous curve.

[0299] As described in the first embodiment, the "reflection phase" refers to the amount of change in the phase of the reflected wave relative to the phase of the incident wave incident on a surface. In the frequency selective reflector having a reflecting member and a dielectric layer of the third embodiment described below, the "reflection phase" refers to the amount of change in the phase of the reflected wave relative to the phase of the incident wave when the incident wave passes through the dielectric layer, is reflected by the reflecting member, passes through the dielectric layer again, and is emitted.

[0300] In the frequency selective reflector of this embodiment, the "relative reflection phase" is expressed by a negative sign as the delay of the reflection phase in a certain cell region with respect to the reference reflection phase, with the reflection phase in the cell region with the largest reflection phase lead as a reference. For example, if the reflection phase in the cell region with the largest reflection phase lead is -10 degrees, the relative reflection phase in a cell region with a reflection phase of -40 degrees will be -30 degrees.

[0301] Note that "the lead of the reflection phase is the largest" means that when the reflection phase is 0 degrees or less in all cell regions, the delay of the reflection phase is the smallest.

[0302] As described later, in the frequency selective reflector having the reflecting member and the dielectric layer of the third embodiment, the relative reflection phase of the electromagnetic wave in the cell region is a value based on the reflection phase at the dielectric layer, regardless of whether the reflecting member has a reflection phase control function or not. In other words, the relative reflection phase of the electromagnetic wave in the cell region is not based on a value obtained by combining the reflection phase at the dielectric layer and the reflection phase at the reflecting member.

[0303] In the frequency selective reflector of this embodiment, the "cell region" refers to a region in which the relative reflection phase of electromagnetic waves is the same.

[0304] In the frequency selective reflector of this embodiment, the reflection phase is within a range of more than -360 degrees and less than +360 degrees unless otherwise specified, and -360 degrees and +360 degrees return to 0 degrees. In the frequency selective reflector of this embodiment, the relative reflection phase is within a range of more than -360 degrees and 0 degrees or less unless otherwise specified, and -360 degrees returns to 0 degrees.

[0305] The boundary portion where the gradually decreasing relative reflection phase of the electromagnetic wave suddenly increases is a portion where the relative reflection phase gradually decreases from 0 degrees toward -360 degrees, and then suddenly increases toward 0 degrees.

[0306] In addition, in the frequency selective reflector of this embodiment, "curved" not only refers to a curved line, but also includes a state in which a series of straight lines looks like a curve when viewed as a whole, or a state in which some straight lines are included but which approximates a curve.

[0307] In the frequency selective reflector of this embodiment, the term "continuous curved line" means a curved line without interruption, specifically, the boundary portion is not interrupted. In the frequency selective reflector of this embodiment, the term "unbranched curved line" means a curved line without branching, specifically, the boundary portion is not branched.

[0308] Moreover, the curved shape may be, for example, an open curved shape or a closed curved shape.

[0309] Examples of the curved shape include a circular arc shape, a gourd-like curve, and a curve whose curvature changes gradually.

[0310] Fig. 32(a) is a schematic plan view illustrating a cell region in a frequency selective reflector of this embodiment. The frequency selective reflector shown in Fig. 32(a) has a reflecting member in which a plurality of ring-shaped reflecting elements 3 having different outer diameters are arranged as shown in Fig. 32(b). Fig. 32(b) corresponds to the portion enclosed by frame line F1 in Fig. 32(a), and the numbers in Fig. 32(a) indicate the outer radius of the ring of the reflecting elements 3. In this frequency selective reflector, an element region in which one reflecting element 3 is arranged is one cell region, and as the outer radius of the ring of the reflecting element 3 increases, the relative reflection phase of the electromagnetic wave in each cell region decreases.

[0311] In Fig. 32(a) and (b), the relative reflection phase of the electromagnetic wave in each cell region repeatedly increases and decreases in a certain direction. In Fig. 32(a) and (b), the boundary portion where the gradually decreasing relative reflection phase of the electromagnetic wave suddenly increases is the portion where the gradually increasing outer radius of the ring of the reflecting element suddenly decreases. In Fig. 32(a), this boundary portion is indicated by a thick line F2. The boundary portion is not branched but is a continuous curved line. On the other hand, in Fig. 32(a), since there is no column to the right of the cell region in the rightmost column, the above boundary portion is considered to be indicated by, for example, a dashed line F3, but it is not possible to determine whether the above boundary portion exists between the cell region in the rightmost column and the column to the right of the cell region. Therefore, the above boundary portion appears to be interrupted in the frame line F4. However, the above boundary portion is considered to be indicated by, for example, a dashed line F3, and if the dashed line F3 is included, the above boundary portion becomes an uninterrupted curved line, that is, a continuous curved line. Therefore, in the frequency selective reflector of this embodiment, the boundary portion of the outermost cell region does not need to be branched or have a continuous curved shape.

[0312] In addition, in Figures 32(a) and (b), each cell area can be considered as a matrix arranged in a lattice. The minimum resolution for expressing the in-plane layout of the relative reflection phase of electromagnetic waves is the size of the cell area. This can be considered similar to a display that displays information by arranging pixels. For example, in Figure 32(a), Figure 32(c) shows a schematic layout matrix of the cell areas when the lower left is the origin O, the horizontal direction is the x-axis, and the up and down direction is the y-axis. A situation in which the above-mentioned boundary part exists as a straight line sloping upward to the right of y = x is expressed by a crank-shaped bend of one cell area continuing upward to the right, as shown by the solid line F11. The solid line F11 should be considered as a substantial straight line. Similarly, when the above-mentioned boundary part exists as a straight line sloping upward to the right of y = x, 2 The situation that exists according to the curve of is expressed as a curve that rises to the right and includes a crank-shaped bend of one cell area, as shown by the dashed line F12. The dashed line F12 should also be considered to be a curve in effect. Therefore, when expressing the boundary portion where the gradually decreasing relative reflection phase of the electromagnetic wave suddenly increases with the thick line F2, the crank-shaped bend of one cell area can be considered as a smooth change rather than as an inflection point.

[0313] In addition, in the frequency selective reflector of this embodiment, the boundary portion may have a portion that is not branched and is not a continuous curved shape. Hereinafter, the boundary portion that is not branched and is not a continuous curved shape may be referred to as a noise portion. For example, as described later, when the frequency selective reflector has a reflecting member that reflects electromagnetic waves, and a plurality of reflecting elements of different sizes are repeatedly arranged in the reflecting member, examples of the noise portion include, for example, an error in the size or shape of the reflecting element, and in extreme cases, a loss of the reflecting element. Also, for example, as described later, when the frequency selective reflector has a reflecting member that reflects electromagnetic waves and a dielectric layer that is arranged on the electromagnetic wave incident side of the reflecting member and transmits the electromagnetic wave, and a plurality of dielectric cell regions of different thicknesses are repeatedly arranged in the dielectric layer, examples of the noise portion include, for example, an error in the thickness or shape of the dielectric cell region, an error in the size or shape of the reflecting element of the reflecting member, and in extreme cases, a loss of the reflecting element or a loss of the dielectric layer. Also, examples of the noise portion include, for example, a structure that is not related to the control of the reflection phase of the electromagnetic wave. Examples of the structure that is not related to the control of the reflection phase of the electromagnetic wave include a support member and an alignment mark. The support member is, for example, a member that supports a cover member when the cover member is placed. The structure that is not related to the control of the reflection phase of the electromagnetic wave may be a structure that is intentionally placed, or may be a structure that is formed by chance. Examples of the material of the structure that is not related to the control of the reflection phase of the electromagnetic wave include a metal material, a conductive material, and a non-conductive material.

[0314] For example, when a support member is disposed on the outer periphery of the frequency selective reflector, the support member can be considered to be located outside the effective area of ​​the frequency selective reflector. Therefore, in this case, the support member is not considered to be a noise part. As described above, the boundary part of the outermost cell area does not have to be branched or have a continuous curved shape, so the outermost cell area is also not considered to be a noise part.

[0315] The noise portion is confirmed by the following method.

[0316] As described later, for example, when a frequency selective reflector has a reflecting member that reflects electromagnetic waves, and a plurality of reflecting elements of different sizes are repeatedly arranged in the reflecting member, the boundary portion where the gradually decreasing relative reflection phase of the electromagnetic waves suddenly increases is the portion where the gradually increasing size of the reflecting elements suddenly decreases. Therefore, by checking the increase or decrease in the size of the reflecting elements, the noise portion can be confirmed. If the portion where the gradually increasing size of the reflecting elements suddenly decreases is branched or interrupted, it is determined that there is a noise portion. The noise portion can be confirmed visually or with a magnifying glass.

[0317] Also, as described later, for example, when a frequency selective reflector has a reflecting member that reflects electromagnetic waves and a dielectric layer that is arranged on the electromagnetic wave incident side of the reflecting member and transmits electromagnetic waves, and when a plurality of dielectric cell regions with different thicknesses are repeatedly arranged in the dielectric layer, the boundary portion where the relative reflection phase of the gradually decreasing electromagnetic waves suddenly increases is the portion where the thickness of the gradually thickening dielectric cell region suddenly decreases. In other words, the boundary portion where the relative reflection phase of the gradually decreasing electromagnetic waves suddenly increases is the ridge-like portion of the dielectric layer. Therefore, by checking the increase or decrease in the thickness of the dielectric cell region, the noise portion can be confirmed. If the portion where the thickness of the gradually thickening dielectric cell region suddenly decreases is branched or interrupted, it is determined that there is a noise portion. Regarding the reflecting member, the confirmation of the noise portion is as described above. Regarding the dielectric layer, a stylus step gauge or a laser microscope is used to confirm the noise portion.

[0318] The noise portion may be one or more.

[0319] For example, when the wavelength of the electromagnetic wave is λ, the size of the noise part is preferably 2λ×2λ or less, more preferably λ×λ or less, and even more preferably λ / 2×λ / 2 or less. If the size of the noise part is too large, the performance of the frequency selective reflector is reduced. Therefore, it is necessary to increase the size of the frequency selective reflector to compensate for this. Also, if the size of the noise part is λ / 2×λ / 2 or less, resonance is unlikely to occur, and the reflection intensity of the electromagnetic wave is rapidly reduced. On the other hand, the lower limit of the size of the noise part is not particularly limited.

[0320] The size of the noise part refers to the size of one noise part. If the noise part is, for example, an error in the size or shape of a reflecting element of a reflecting member, or an error in the thickness or shape of a dielectric cell region, the size of the noise part is the size of the cell region in which the reflecting element has an error in size or shape, or the size of the dielectric cell region in which the thickness or shape has an error. If the noise part is, for example, a support member or an alignment mark, the size of the noise part is the size of the support member or the size of the alignment mark.

[0321] In addition, the ratio of the total area of ​​the noise portion to the total area of ​​the cell region is preferably 20% or less, more preferably 10% or less, and even more preferably 5% or less. If the ratio is too high, the performance of the frequency selective reflector decreases. Therefore, it is necessary to increase the size of the frequency selective reflector to compensate for this. On the other hand, the lower limit of the ratio is not particularly limited.

[0322] Here, the ratio of the total area of ​​the noise parts to the total area of ​​the cell regions is measured by the following method. First, a region having a size of 1 / 25 of the entire frequency selective reflector is randomly selected. The noise parts are confirmed for this selected region as described above. Then, the ratio of the total area of ​​the noise parts to the total area of ​​the cell regions included in this selected region is calculated. At this time, if the ratio is within the above range, the ratio in the selected region is considered to be the ratio of the total area of ​​the noise parts to the total area of ​​the cell regions in the entire frequency selective reflector. On the other hand, if the ratio exceeds the above range, the noise parts are further confirmed for the entire frequency selective reflector as described above. Then, the ratio of the total area of ​​the noise parts to the total area of ​​the cell regions is calculated. At this time, if a support member is arranged on the outer periphery of the frequency selective reflector as described above, the support member is not a noise part, so it is not included in the total area of ​​the noise parts.

[0323] It is particularly preferable that the size of the noise portion is within the above range, and the ratio of the total area of ​​the noise portion to the total area of ​​the cell region is within the above range.

[0324] 2. Structure of frequency selective reflector The frequency selective reflector is not particularly limited as long as it is a member that reflects electromagnetic waves of a specific frequency band in a direction different from the regular reflection direction. For example, the frequency selective reflector has a reflecting member that reflects the electromagnetic waves, and the reflecting member may have a plurality of reflecting elements of different sizes arranged repeatedly. For example, the frequency selective reflector may have a reflecting member that reflects the electromagnetic waves, and a dielectric layer that is arranged on the incident side of the electromagnetic waves with respect to the reflecting member and transmits the electromagnetic waves, and the dielectric layer may have a plurality of dielectric cell regions of different thicknesses arranged repeatedly. For example, the frequency selective reflector may be a variable frequency selective reflector that controls the reflection phase of the electromagnetic waves by electrical control or mechanical control to change the reflection direction of the electromagnetic waves.

[0325] Below, we will explain the third embodiment in which the frequency selective reflector has a reflecting member that reflects the electromagnetic wave, in which a plurality of reflecting elements of different sizes are repeatedly arranged, and the fourth embodiment in which the frequency selective reflector has a reflecting member that reflects the electromagnetic wave, and a dielectric layer that is arranged on the incident side of the electromagnetic wave relative to the reflecting member and transmits the electromagnetic wave, in which a plurality of dielectric cell regions of different thicknesses are repeatedly arranged.

[0326] (1) Third embodiment of frequency selective reflector A third aspect of the frequency selective reflector of this embodiment has a reflecting member that reflects the electromagnetic wave, and in the reflecting member, a plurality of reflecting elements of different sizes are repeatedly arranged. In the reflecting member of this embodiment, by changing the size of the reflecting element, the resonant frequency can be changed for each reflecting element, and the reflection phase of the electromagnetic wave can be controlled. This makes it possible to control the reflection direction of the electromagnetic wave incident from a predetermined direction. Therefore, in the frequency selective reflector of this embodiment, since the reflecting member has a plurality of reflecting elements of different sizes repeatedly arranged, the reflecting member can have a reflection phase control function that controls the reflection phase of the electromagnetic wave, and further, can have a wavelength selection function, that is, FSS, that reflects only electromagnetic waves in a specific frequency band.

[0327] (a) Reflective material The reflective member in this embodiment is a member that reflects electromagnetic waves in a specific frequency band. The reflective member has a plurality of reflective elements of different sizes arranged in a repeated fashion.

[0328] The shape of the reflective element is not particularly limited, and may be any shape, such as a ring, cross, square, rectangle, polygon, circle, ellipse, rod, planar patterns such as a pattern divided into multiple adjacent regions, and three-dimensional structures such as through-hole vias.

[0329] The different sizes of the reflective elements are appropriately selected according to the shape of the reflective elements. For example, in the case of rings, the rings are similar in shape and the outer diameters of the rings are different. In the case of crosses, one or both of the lengths of the two lines of the cross are different. In the case of squares, the lengths of the sides of the squares are different. In the case of rectangles, the rectangles are similar in shape and one or both of the long side length or short side length of the rectangle are different. In the case of polygons such as hexagons, octagons, etc., the polygons are similar in shape and the lengths of the sides of the polygons are different. In the case of circles, the diameters of the circles are different. In the case of ellipses, the ellipses are similar in shape and one or both of the long axis diameter or short axis diameter of the ellipse are different. In the case of rods, the lengths of the rods are different.

[0330] In general, as the size of the reflecting element increases, the relative reflection phase of the electromagnetic wave decreases. Therefore, the boundary portion where the gradually decreasing relative reflection phase of the electromagnetic wave suddenly increases is the portion where the gradually increasing size of the reflecting element suddenly decreases. Specifically, if an element region where one reflecting element is arranged among a plurality of reflecting elements of different sizes is taken as a cell region, in the portion where the gradually increasing size of the reflecting element suddenly decreases, the boundary line between the element region where the large-sized reflecting element is arranged and the element region where the small-sized reflecting element is arranged is the above-mentioned boundary portion.

[0331] Therefore, by checking the change in the size of the reflecting element, it is possible to check the change in the relative reflection phase of the electromagnetic wave.Furthermore, by checking the portion where the gradually increasing size of the reflecting element suddenly decreases, it is possible to check the boundary portion where the gradually decreasing relative reflection phase of the electromagnetic wave suddenly increases.

[0332] In this embodiment, the "cell region" refers to a region in which the relative reflection phase of electromagnetic waves is the same, and refers to an element region in which one reflecting element is arranged among a plurality of reflecting elements having different sizes.

[0333] In the plurality of reflecting elements having different sizes, the sizes are preferably 3 or more, and 6 or more. The more the number of different sizes of the reflecting elements, the smaller the difference in the relative reflection phase of the electromagnetic wave in the adjacent cell regions can be, and the smoother the wavefront of the reflected wave can be. In addition, the more the number of different sizes of the reflecting elements, the more preferable it is, and although there is no particular upper limit, for example, 80 types are considered sufficient.

[0334] The reflective member can include, for example, a dielectric substrate and a plurality of reflective elements disposed on one surface of the dielectric substrate.

[0335] In addition, the reflective element may be, for example, a single layer or a multilayer. When the reflective element is a single layer or a multilayer, the configuration of the reflective member may be the same as that of the first aspect of the first embodiment described above.

[0336] (b) Other configurations The frequency selective reflector of this aspect may have other configurations as necessary in addition to the above-mentioned reflecting member. The other configurations may be the same as those of the first aspect of the above-mentioned first embodiment.

[0337] In addition, when the reflective member has a dielectric substrate and a plurality of reflective elements arranged on the electromagnetic wave incident surface of the dielectric substrate, an FSS may be arranged on the surface of the dielectric substrate opposite the electromagnetic wave incident surface.

[0338] (2) Fourth embodiment of frequency selective reflector A fourth aspect of the frequency selective reflector of this embodiment includes a reflecting member that reflects the electromagnetic wave, and a dielectric layer that is disposed on the electromagnetic wave incident side of the reflecting member and transmits the electromagnetic wave, and a plurality of dielectric cell regions with different thicknesses are repeatedly arranged in the dielectric layer. In the frequency selective reflector of this embodiment, by changing the thickness of each dielectric cell region of the dielectric layer, the round-trip optical path length in the dielectric layer can be changed for each dielectric cell region, and the reflection phase of the electromagnetic wave can be controlled. This makes it possible to control the reflection direction of the electromagnetic wave relative to a predetermined incident direction to any direction.

[0339] (a) Dielectric layer The dielectric layer in this embodiment is a member that is disposed on the electromagnetic wave incident side of the reflecting member and transmits electromagnetic waves in a specific frequency band. In addition, the dielectric layer has a plurality of dielectric cell regions with different thicknesses repeatedly arranged.

[0340] As described in the first embodiment above, as the thickness of the dielectric cell region increases, the relative reflection phase of the electromagnetic wave decreases. Therefore, the boundary portion where the relative reflection phase of the gradually decreasing electromagnetic wave suddenly increases is the portion where the thickness of the gradually increasing dielectric cell region suddenly decreases. In other words, the boundary portion where the relative reflection phase of the gradually decreasing electromagnetic wave suddenly increases is the ridge portion of the dielectric layer. Specifically, if the dielectric cell region is the cell region, the boundary line between the thick dielectric cell region and the thin dielectric cell region in the ridge portion of the dielectric layer is the above-mentioned boundary portion.

[0341] As mentioned above, the "ridge portion of the dielectric layer" refers to the portion where the thickness of the dielectric cell region, which gradually increases, suddenly decreases.

[0342] Therefore, by checking the change in thickness of the dielectric layer, it is possible to check the change in the relative reflection phase of the electromagnetic wave.Furthermore, by checking the ridge-like portion of the dielectric layer, it is possible to check the boundary portion where the gradually decreasing relative reflection phase of the electromagnetic wave suddenly increases.

[0343] In this embodiment, the "cell region" refers to a region in which the relative reflection phase of electromagnetic waves is the same, and refers to a dielectric cell region.

[0344] In the plurality of dielectric cell regions having different thicknesses, the thicknesses are preferably three or more, and more preferably six or more. The greater the number of thicknesses of the dielectric cell regions, the smaller the difference in the relative reflection phase of the electromagnetic wave in the adjacent cell regions, and the smoother the wavefront of the reflected wave. The greater the number of thicknesses of the dielectric cell regions, the more preferable it is, and there is no particular upper limit. In addition, when the cross-sectional shape of the dielectric layer is a step shape, the number of thicknesses of the dielectric cell regions corresponds to the number of steps of the step shape. In addition, when the cross-sectional shape of the dielectric layer is a tapered shape, as described above, the tapered shape can be regarded as an infinitely large number of thicknesses of the dielectric cell regions.

[0345] The relative reflection phase of the electromagnetic wave in each dielectric cell region can be the same as that in the second aspect of the above-mentioned first embodiment.

[0346] Moreover, the structure, characteristics, material, and formation method of the dielectric layer may be the same as those of the second aspect of the first embodiment described above.

[0347] (b) Reflective material The reflective member in this aspect may be the same as that in the second aspect of the first embodiment described above.

[0348] (c) Controlling the direction of electromagnetic wave reflection In the frequency selective reflector of this aspect, the reflection direction of the electromagnetic wave can be controlled in the same manner as in the second aspect of the above-mentioned first embodiment.

[0349] (d) Other configurations The frequency selective reflector of this embodiment may have other configurations as necessary in addition to the above-mentioned reflecting member and dielectric layer. The other configurations may be the same as those of the second embodiment of the above-mentioned first embodiment.

[0350] (3) Other aspects of frequency selective reflectors The frequency selective reflector of this embodiment may be a variable frequency selective reflector that controls the reflection phase of the electromagnetic wave by electrical control or mechanical control, thereby varying the reflection direction of the electromagnetic wave, as described above. This embodiment can be realized even in the case of such a variable frequency selective reflector. Known variable frequency selective reflectors can be used.

[0351] 3. Other points about frequency selective reflectors Other aspects of the frequency selective reflector of this embodiment can be similar to those of the first embodiment described above.

[0352] In this embodiment, when the entire surface of the frequency selective reflector is divided into multiple virtual divided regions, it is preferable to set the reflection direction vector of the electromagnetic wave in each virtual divided region in the same manner as the frequency selective reflectors of the first to fourth embodiments described above.

[0353] In addition, the reflection direction vector of the electromagnetic wave in each virtual divided area may be set to spread outward with respect to the reflection direction vector of the electromagnetic wave at the center, or may be set to converge inward. In addition, the reflection direction vector of the electromagnetic wave in each virtual divided area may be set to spread outward in the horizontal direction with respect to the reflection direction vector of the electromagnetic wave at the center, and may be set to converge inward in the vertical direction. Alternatively, the reflection direction vector of the electromagnetic wave in each virtual divided area may be set to spread outward in the vertical direction with respect to the reflection direction vector of the electromagnetic wave at the center, and may be set to converge inward in the horizontal direction. By setting the reflection direction vector of the electromagnetic wave in each virtual divided area in this way, it is possible to arbitrarily control the area to which the reflected beam is irradiated.

[0354] B. Communication Relay System The communication relay system of the present disclosure is a communication relay system that relays communications between a base station and a user terminal, and has a plurality of directional control devices that change the direction of propagation of electromagnetic waves in a specific frequency band, each of the plurality of directional control devices being arranged on the propagation path of the electromagnetic waves from the base station, and having one or more of the above-mentioned frequency selective reflectors as the directional control devices.

[0355] Here, to eliminate coverage holes, it is effective to use a reflectarray that can reflect electromagnetic waves in a direction different from the regular reflection direction. Reflectarrays are advantageous in terms of installation and running costs compared to adding base stations and relay stations.

[0356] The reflectarray needs to be placed at a position where it can receive electromagnetic waves from the base station and reflect the electromagnetic waves to the user terminal. That is, the reflectarray needs to be installed at a position where it can be seen from both the base station and the user terminal. However, in an actual usage environment, depending on the position of an electromagnetic wave obstacle, it may be difficult to place the reflectarray at the above-mentioned position. Therefore, even if the reflectarray is used, there is a problem that the desired propagation environment and propagation area improvement effect cannot be obtained. For example, as shown in FIG. 33(a), when a base station 41, a coverage hole 42, and an electromagnetic wave obstacle 43 are located, as shown in FIG. 33(b), even if the reflectarray RA1 is placed at position P1, the electromagnetic wave is blocked by the electromagnetic wave obstacle 43, and the electromagnetic wave does not reach a part of the coverage hole 42. Therefore, as shown in Figure 33(b), it is possible to use another reflect array RA2 to receive electromagnetic waves from base station 41 and reflect them to the remaining area 44 where the electromagnetic waves do not reach, but there is no position that can receive electromagnetic waves from base station 41 and reflect the electromagnetic waves to the remaining area 44 where the electromagnetic waves do not reach.

[0357] The above problem can be solved by combining multiple reflectarrays. For example, as shown in Fig. 33(c), the electromagnetic waves from a reflectarray RA1 can be reflected by another reflectarray RA2 to the remaining area 44 where the electromagnetic waves do not reach.

[0358] As described above, when the distance between the base station and the reflectarray is sufficiently large, the incident wave from the base station can be regarded as a plane wave. On the other hand, when the reflectarray is located near the base station, the incident wave from the base station needs to be treated as a spherical wave. However, in the design of conventional reflectarrays, the incident wave is assumed to be a plane wave. Therefore, in the conventional reflectarray, when a spherical wave is incident, the reflected beam spreads unintentionally. Therefore, even if multiple reflectarrays are used in combination, when the base station and the reflectarray are located close to each other, the reflection characteristics as designed cannot be obtained, and there is a problem that the desired improvement effect of the propagation environment and the propagation area cannot be obtained.

[0359] In contrast, in the communication relay system of the present disclosure, in addition to using a combination of multiple directional control devices, the directional control device has one or more frequency selective reflectors having the function of adjusting the above-mentioned reflected beam profile. As described above, the frequency selective reflector can be applied to both plane waves and spherical waves when the incident wave is a plane wave. Therefore, even when the incident wave is a spherical wave, the reflected beam is prevented from unintentionally spreading, and the reflection characteristics as designed can be obtained. Therefore, in the communication relay system of the present disclosure, it is possible to obtain the desired propagation environment and propagation area improvement effect. In addition, the communication relay system of the present disclosure can be adapted to various usage environments. Furthermore, it is possible to expand the use of frequency selective reflectors, and to promote the development and spread of next-generation mobile communication systems such as 5G.

[0360] The communication relay system according to the present disclosure will be described below.

[0361] 1. Directional control device The directional control device of the present disclosure changes the direction of travel of electromagnetic waves in a specific frequency band.

[0362] The directional control device may be a reflective directional control device that reflects electromagnetic waves, or may be a transmissive directional control device that transmits electromagnetic waves.

[0363] The reflection direction control device is not particularly limited as long as it can reflect the electromagnetic wave and change the traveling direction of the electromagnetic wave, and examples thereof include a metal plate, a sheet having a conductive layer, a reflector that reflects the electromagnetic wave in a specular reflection direction, and a reflector that reflects the electromagnetic wave in a direction different from the specular reflection direction. An example of a reflector that reflects the electromagnetic wave in a specular reflection direction is an FSS. An example of a reflector that reflects the electromagnetic wave in a direction different from the specular reflection direction is a reflect array or the above-mentioned frequency selective reflector. A reflect array is also called a metasurface reflector. The reflection direction control device is appropriately selected depending on the purpose of use and the environment of use.

[0364] The transmission direction control device is not particularly limited as long as it can transmit an electromagnetic wave and change the traveling direction of the electromagnetic wave, and a known transmission direction control device can be used. For example, a dielectric lens antenna, a metasurface lens, a metasurface refraction plate, etc. can be mentioned. The transmission direction control device is appropriately selected depending on the purpose of use and the environment of use.

[0365] The communication relay system of the present disclosure has one or more frequency selective reflectors as the direction control device. As the direction control device, only the frequency selective reflector described above may be used, or the frequency selective reflector described above may be used in combination with other direction control devices. In addition, when the frequency selective reflector described above is used in combination with other direction control devices, the frequency selective reflector may be used in combination with other reflection direction control devices, the frequency selective reflector may be used in combination with a transmission direction control device, or the frequency selective reflector may be used in combination with other reflection direction control devices and a transmission direction control device. When all direction control devices are the frequency selective reflectors described above, the effect of improving the propagation environment and the propagation area can be enhanced. In addition, when other reflection direction control devices are included as direction control devices, existing reflection direction control devices can be used or costs can be reduced. In addition, when a transmission direction control device is included as a direction control device, the propagation path of the electromagnetic wave is appropriately set according to the usage environment.

[0366] The frequency selective reflector may be any of the frequency selective reflectors of the embodiment. In addition, when the direction control device includes a plurality of frequency selective reflectors, the frequency selective reflectors may be used alone or in combination of two or more kinds.

[0367] In particular, the communication relay system of the present disclosure preferably has one or more of the above-mentioned frequency selective reflectors as a direction control device, and one or more of the frequency selective reflectors of the fifth embodiment as a frequency selective reflector. In particular, it is preferable that all the frequency selective reflectors are the frequency selective reflectors of the fifth embodiment.

[0368] In addition, when a plurality of directional control devices other than frequency selective reflectors are included as the directional control device, the directional control devices other than frequency selective reflectors may be used alone or in combination of two or more kinds.

[0369] 2. Placement of directional control devices In the communication relay system of the present disclosure, the multiple direction control devices are each arranged on a propagation path of an electromagnetic wave from a base station. Specifically, the multiple direction control devices are arranged downstream of the base station, the direction control device located on the most upstream side is arranged at a position where it receives part or all of the electromagnetic wave from the base station, and the direction control device located downstream is arranged at a position where it receives part or all of the electromagnetic wave from the direction control device located upstream.

[0370] Note that "upstream" refers to the upstream in the direction of travel of the electromagnetic waves emitted from the base station. Also, "downstream" refers to the downstream in the direction of travel of the electromagnetic waves emitted from the base station. Meanwhile, the electromagnetic waves emitted from the user terminal reach the base station by following a propagation path that is the opposite to the propagation path of the electromagnetic waves from the base station.

[0371] The location of the directional control device is appropriately set depending on the purpose of use and the environment in which it is used.

[0372] For example, a plurality of direction control devices may be arranged so that the electromagnetic wave propagation path is one starting from the base station. Also, a plurality of direction control devices may be arranged so that the electromagnetic wave propagation path branches off from the base station. For example, FIG. 34(a) and FIG. 35(a) are examples in which two or three frequency selective reflectors 1A, 1B, and 1C are arranged so that the electromagnetic wave propagation path is one starting from the base station 41. Also, for example, FIG. 36(a) is an example in which three frequency selective reflectors 1A, 1B, and 1C and one transmission direction control device 51 are arranged so that the electromagnetic wave propagation path is one starting from the base station 41. Also, for example, FIG. 36(b) is an example in which one frequency selective reflector 1 and one transmission direction control device 51 are arranged so that the electromagnetic wave propagation path is one starting from the base station 41. Also, for example, Fig. 35(b) shows an example in which three frequency selective reflectors 1A, 1B, and 1C are arranged so that the propagation path of the electromagnetic wave branches from the base station 41. For example, as shown in Figs. 34(a), 35(b), 36(a), and 36(b), when there is one coverage hole 44 for one base station 41, one propagation path may be formed. On the other hand, when there are multiple coverage holes for one base station, although not shown, multiple propagation paths may be formed so as to branch from the base station, and for example, as shown in Fig. 35(b), a propagation path having a branch may be formed so as to branch in the middle of the propagation path.

[0373] Moreover, the combination of the direction control devices is as described above.

[0374] In the arrangement of the directional control device, the position of the frequency selective reflector is not particularly limited. The frequency selective reflector may be arranged, for example, on the upstream side or the downstream side.

[0375] For example, the direction control device located at the most upstream side may be the above-mentioned frequency selective reflector. In this case, even if the incident wave from the base station is a spherical wave, the frequency selective reflector can convert the spherical wave into a plane wave and reflect it toward the downstream direction control device.

[0376] Also, for example, the direction control device located at the most downstream side may be the above-mentioned frequency selective reflector. In this case, the frequency selective reflector at the most downstream side can widen or narrow the reflected beam. Therefore, the area where the reflected beam is irradiated can be adjusted according to the target coverage hole. Also, the electromagnetic wave can be concentrated on the CPE.

[0377] Among them, the direction control device located on the most downstream side is preferably the above-mentioned frequency selective reflector, and more preferably the frequency selective reflector of the fifth embodiment, which allows the electromagnetic waves from the base station to be appropriately delivered to the user terminal.

[0378] In addition, when the direction control device located at the most upstream side is a reflective direction control device, the reflective direction control device at the most upstream side is positioned at a position where it receives some or all of the electromagnetic waves from the base station, but does not usually reflect all of the electromagnetic waves from the base station.

[0379] In addition, the direction control device located downstream is disposed at a position where it receives a part or all of the electromagnetic wave from the direction control device located upstream. When the direction control device is a frequency selective reflector, the reflection beam profile of the upstream frequency selective reflector may be designed to reflect the electromagnetic wave toward the downstream frequency selective reflector, or the reflection beam profile may be designed to reflect the electromagnetic wave toward an area including the downstream frequency selective reflector.

[0380] The arrangement of the direction control device will be described below with a specific example.

[0381] (1) When using only a frequency selective reflector When only the above-mentioned frequency selective reflector is used as the direction control device, the effect of improving the propagation environment and the propagation area can be enhanced.

[0382] When all the direction control devices are the above-mentioned frequency selective reflectors, the arrangement of the direction control devices is appropriately set according to the purpose of use and the usage environment, as described above.

[0383] First, we will consider an example in which multiple frequency-selective reflectors are arranged so that the electromagnetic wave propagation path starting from the base station becomes one.

[0384] For example, as shown in FIG. 34(a), the usage environment is an L-shaped space 45 surrounded by electromagnetic obstacles 43. In this case, the electromagnetic waves from a base station 41 located outside the L-shaped space 45 are transmitted from one end of the L-shaped space 45 to the other end of the L-shaped space 45. For example, when two frequency selective reflectors are used, an upstream frequency selective reflector 1A is placed at one end of the L-shaped space 45, and a downstream frequency selective reflector 1B is placed near the corner of the L-shaped space 45. The upstream frequency selective reflector 1A is placed at a position where it receives all or part of the electromagnetic waves from the base station 41. The downstream frequency selective reflector 1B is placed at a position where it receives all or part of the electromagnetic waves from the upstream frequency selective reflector 1A.

[0385] In this case, the reflected beam profile of the downstream frequency selective reflector may be adjusted so that the reflected beam is broadened, or may be adjusted so that the reflected beam is narrowed. In the former case, for example, as shown in FIG. 34(a), the upstream frequency selective reflector 1A converts the spherical wave into a substantially plane wave and reflects it, and the downstream frequency selective reflector 1B can broaden the reflected beam. At this time, in the L-shaped space 45, if the coverage hole 42 is wide, the downstream frequency selective reflector 1B can adjust the reflected beam profile so that the reflected beam is broader. The former example is an example of eliminating the coverage hole. In the latter case, the upstream frequency selective reflector converts the spherical wave into a substantially plane wave and reflects it, and the downstream frequency selective reflector can narrow the reflected beam. The latter example is an example of concentrating the electromagnetic wave on the CPE.

[0386] In this case, the reflected beam profile may be adjusted in the upstream frequency selective reflector so that the reflected beam is broadened, or the reflected beam profile may be adjusted so that the reflected beam is narrowed. In the former case, the reflected beam can be broadened by both the upstream frequency selective reflector and the downstream frequency selective reflector. In this case, when the downstream frequency selective reflector is disposed at a position where it receives a part of the electromagnetic wave from the upstream frequency selective reflector, the downstream frequency selective reflector can deliver a part of the reflected beam broadened by the upstream frequency selective reflector to the coverage hole. In the latter case, the upstream frequency selective reflector can narrow the reflected beam, and the downstream frequency selective reflector can widen the reflected beam. In this case, by narrowing the reflected beam in the middle of the propagation path, unnecessary reflections due to electromagnetic wave obstacles can be suppressed, and the electromagnetic wave can be concentrated toward the downstream frequency selective reflector. Therefore, the propagation loss can be reduced, and the electromagnetic wave can be delivered efficiently.

[0387] Also, as shown in FIG. 35(a), for example, the use environment is a crank space 46 surrounded by electromagnetic wave obstacles 43. In this case, the case where electromagnetic waves from a base station 41 located outside the crank space 46 are delivered from one end of the crank space 46 to a coverage hole 42 at the other end of the crank space 46 is illustrated. For example, when three frequency selective reflectors are used, an upstream frequency selective reflector 1A is arranged at one end of the crank space 46, a midstream frequency selective reflector 1B is arranged near the first bend of the crank space 46, and a downstream frequency selective reflector 1C is arranged near the second bend of the crank space 46. The upstream frequency selective reflector 1A is arranged at a position where it receives all or part of the electromagnetic waves from the base station 41. The midstream frequency selective reflector 1B is arranged at a position where it receives all or part of the electromagnetic waves from the upstream frequency selective reflector 1A. The downstream frequency selective reflector 1C is disposed at a position where it receives all or a part of the electromagnetic waves from the midstream frequency selective reflector 1B.

[0388] In this case, in each of the frequency selective reflectors 1A, 1B, and 1C, the reflected beam profile may be adjusted so that the reflected beam is broadened, or the reflected beam profile may be adjusted so that the reflected beam is narrowed.

[0389] For example, the reflected beam may be narrowed at the upstream frequency selective reflector 1A, narrowed at the midstream frequency selective reflector 1B, and widened at the downstream frequency selective reflector 1C. In this case, by narrowing the reflected beam midway along the propagation path, it is possible to suppress unnecessary reflections from electromagnetic wave obstacles 43 and concentrate the electromagnetic wave toward the downstream frequency selective reflector 1C. This reduces propagation loss and allows the electromagnetic wave to be delivered efficiently.

[0390] Next, an example will be given in which a plurality of direction control devices are arranged so that the propagation path of the electromagnetic wave branches off from a base station as a starting point.

[0391] As shown in FIG. 35(b), the usage environment is a space 47 surrounded by an electromagnetic obstacle 43 and having two corners 48 and 49 in different directions. In this case, the electromagnetic waves from a base station 41 located outside the space 47 are transmitted from one end of the space 47 to the back of one corner 48 and to the back of the other corner 49. For example, when three frequency selective reflectors are used, an upstream frequency selective reflector 1A is placed at one end of the space 47, a downstream frequency selective reflector 1B is placed near the first corner 48, and another downstream frequency selective reflector 1C is placed near the second corner 49. The upstream frequency selective reflector 1A is placed at a position where it receives all or part of the electromagnetic waves from the base station 41. The downstream frequency selective reflector 1B is placed at a position where it receives part of the electromagnetic waves from the upstream frequency selective reflector 1A. The other downstream frequency selective reflector 1C is disposed at a position where it receives the remaining part of the electromagnetic waves from the upstream frequency selective reflector 1A.

[0392] In this case, the reflected beam profile is adjusted in the upstream frequency selective reflector 1A so that the reflected beam is broadened. Also, the reflected beam profile may be adjusted in the downstream frequency selective reflectors 1B and 1C so that the reflected beam is broadened or narrowed.

[0393] For example, as shown in FIG. 35(b), the reflected beam may be expanded by all of the frequency selective reflectors 1A, 1B, and 1C.

[0394] Also, an example is given of a usage environment consisting of two spaces surrounded by electromagnetic obstacles. Each space has a corner, and one of the spaces is an L-shaped space. In this case, an example is given of an electromagnetic wave from one base station located outside the two spaces reaching the depths of each of the two spaces. For example, when three frequency selective reflectors are used, two frequency selective reflectors are placed in one space, and one frequency selective reflector is placed in the other space.

[0395] In this case, in one of the L-shaped spaces, an upstream frequency selective reflector is placed at one end of the L-shaped space, and a downstream frequency selective reflector is placed near the corner of the L-shaped space. The upstream frequency selective reflector is placed at a position where it receives all or part of the electromagnetic waves from the base station. The downstream frequency selective reflector is placed at a position where it receives all or part of the electromagnetic waves from the upstream frequency selective reflector. In this case, the downstream frequency selective reflector may have a reflected beam profile adjusted so that the reflected beam is broadened, or may have a reflected beam profile adjusted so that the reflected beam is narrowed. For example, in one of the spaces, the upstream frequency selective reflector may convert a spherical wave into a plane wave and reflect it, and the downstream frequency selective reflector may widen the reflected beam.

[0396] In the other space, a frequency selective reflector is placed near a corner. The frequency selective reflector is placed at a position where it receives all or part of the electromagnetic waves from the base station. In this case, the frequency selective reflector may have a reflected beam profile adjusted so that the reflected beam is broadened, or may have a reflected beam profile adjusted so that the reflected beam is narrowed.

[0397] As described above, the reflected beam profile of each frequency selective reflector may be adjusted to widen the reflected beam or narrow the reflected beam. When the reflected beam is widened, coverage holes can be eliminated. When the reflected beam is narrowed, the propagation loss can be reduced or the electromagnetic waves can be concentrated on the CPE.

[0398] For the frequency selective reflector located at the most downstream side, the reflected beam profile may be adjusted appropriately according to the size and shape of the coverage hole. When the reflected beam is to be widened, the reflected beam may be widened horizontally but not vertically because the ceiling and floor may be electromagnetic wave obstacles. When the reflected beam is to be widened, if the coverage hole has a space that widens vertically, such as a staircase, the reflected beam may be widened vertically but not horizontally. When the coverage hole has a CPE, the reflected beam profile may be adjusted to narrow the reflected beam and concentrate the electromagnetic waves toward the CPE.

[0399] (2) When a frequency selective reflector and a transmission direction control device are used in combination When the above-mentioned frequency selective reflector and transmission direction control device are used in combination as a direction control device, the propagation path of the electromagnetic waves is appropriately set according to the usage environment.

[0400] When the above-mentioned frequency selective reflector and transmission direction control device are used in combination as a direction control device, the arrangement of the direction control device is appropriately set according to the purpose of use and the environment of use, as described above.

[0401] In the arrangement of the direction control devices when only frequency selective reflectors are used as the direction control devices as described above, some of the frequency selective reflectors can be replaced with transmission direction control devices. In this case, the transmission direction control devices only need to be arranged on the path of the electromagnetic waves. Since the transmission direction control devices transmit the electromagnetic waves, they are arranged at positions different from the frequency selective reflectors.

[0402] For example, the transmission direction control device can be installed in a window or a wall opening. In this case, a propagation path of the electromagnetic wave can be formed through the window or the wall opening. For example, in FIG. 36(a), the transmission direction control device 51 is installed in a window, and the direction control device located on the most downstream side is the transmission direction control device 51. The transmission direction control device 51 can deliver the electromagnetic wave to the indoor coverage hole 42.

[0403] Furthermore, for example, when there is a restriction on the location where a frequency-selective reflector can be installed, a transmission direction control device can be used to ensure a propagation path for the electromagnetic wave. For example, a transmission direction device can be placed on the upstream side, and a frequency-selective reflector can be placed on the downstream side. In this case, the upstream transmission direction control device can be used to bend the propagation direction of the electromagnetic wave toward the downstream frequency-selective reflector.

[0404] Furthermore, for example, if there is a restriction on the location where the frequency selective reflector can be installed and the difference between the incident angle and the reflection angle needs to be about 180°, there is a concern that the reflection efficiency of the reflection direction control device will be significantly reduced. Therefore, in such a case, it is better to use a transmission direction control device. For example, as shown in Fig. 36(b), the frequency selective reflector 1 on the upstream side can reflect the spherical wave from the base station 41 as a plane wave, and the transmission direction control device 51 on the downstream side can bend the traveling direction of the electromagnetic wave.

[0405] (3) When using a frequency selective reflector in combination with other reflection direction control devices When the above-mentioned frequency selective reflector and other reflective direction control devices are used in combination as a direction control device, the arrangement of the direction control device is appropriately set according to the purpose of use and the environment of use, as described above.

[0406] In the arrangement of the direction control devices when only frequency selective reflectors are used as the direction control devices as described above, some of the frequency selective reflectors can be replaced with other reflective direction control devices.

[0407] Other reflection direction control devices do not have a function for adjusting the reflection beam profile, so when a spherical wave is incident, the reflected beam spreads unintentionally. Therefore, it is preferable to place a frequency selective reflector upstream of the other reflection direction control devices and convert the spherical wave from the base station into a plane wave by the frequency selective reflector located upstream.

[0408] (4)Other When radiating electromagnetic waves from an upstream directional control device toward a downstream directional control device, it is preferable, from the standpoint of efficiency, not to expand the electromagnetic waves more than necessary than the size of the downstream directional control device.

[0409] In addition, when a downstream directional control device receives part of the electromagnetic waves from an upstream directional control device and radiates them to a further downstream area or to a further downstream directional control device, it is necessary to ensure the signal strength from the upstream side so that the propagation environment and propagation area can be improved at the most downstream side. In this case, for example, the signal strength can be ensured by increasing the size of the upstream directional control device.

[0410] 3.Communication Relay System The communication relay system in the present disclosure relays communication between a base station and a user terminal, which may be a general base station and a general user terminal, respectively.

[0411] The present disclosure is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present disclosure and exhibits similar effects is included in the technical scope of the present disclosure. EXAMPLES

[0412] The present disclosure will now be described in detail with reference to examples.

[0413] In addition, all of Examples 1 to 3, Comparative Example 1, and Reference Example 1 were designed so that an electromagnetic wave of 28 GHz incident from a direction of azimuth angle φ=0° and polar angle θ=0° would be reflected in a direction of azimuth angle φ=0° and polar angle θ=27°. In addition, the reflected beam profiles shown in Figures 37 to 41 are plots of the polar angle θ when cut at a plane with an azimuth angle φ=0° on the horizontal axis and the reflection intensity of the electromagnetic wave in the polar angle direction on the vertical axis.

[0414] [Example 1] A simulation was performed on the reflection characteristics of a frequency selective reflector. The following model was used in the simulation. In the model, the length of one side is 80 cm. Multiple reflection elements are periodically arranged. In other words, multiple unit structures having multiple cell regions with different reflection phases of electromagnetic waves are arranged. Each cell region is considered a divided region. In the above model, the reflection direction vector of the electromagnetic wave in each divided region was designed to obtain an irradiation area with a half-width FWHM of 4.5° centered on the polar angle θ=27°. The simulation results are shown in Figure 37.

[0415] [Example 2] A simulation was performed on the reflection characteristics of a frequency selective reflector. The following model was used in the simulation. In the model, the length of one side is 80 cm. Multiple reflection elements are periodically arranged. In other words, multiple unit structures having multiple cell regions with different reflection phases of electromagnetic waves are arranged. It is divided into three divided regions, and two sub-regions are arranged symmetrically on either side of the main region. In addition, in the above model, the reflection direction vector of the electromagnetic wave in each divided region was designed to obtain an irradiation area with a half-width FWHM of 6.5° centered on the polar angle θ=27°. The simulation results are shown in Figure 38.

[0416] [Comparative Example 1] A simulation was performed on the reflection characteristics of a frequency selective reflector. The following model was used in the simulation. In the model, the length of one side is 80 cm. Multiple reflecting elements are randomly arranged. In other words, multiple cell regions with different reflection phases of electromagnetic waves are randomly arranged. Each cell region is considered a divided region. In the above model, the reflection phase of each cell region in a frequency selective reflector that reflects at a polar angle θ=27° was changed by a random number with a standard deviation of 60% from the design value. The simulation results are shown in Figure 39.

[0417] [Example 3] A simulation was performed on the reflection characteristics of a frequency selective reflector. The following model was used in the simulation. In the model, the length of one side is 30 cm. Multiple reflection elements are periodically arranged. In other words, multiple unit structures having multiple cell regions with different reflection phases of electromagnetic waves are arranged. Each cell region is considered a divided region. In the above model, the reflection direction vector of the electromagnetic wave in each divided region was designed to obtain an irradiation area with a half-width FWHM of 6.5° centered on the polar angle θ=27°. The simulation results are shown in Figure 40.

[0418] [Reference example 1] A simulation of the reflection characteristics of the frequency selective reflector was performed. The following model was used in the simulation. In the model, the length of one side is 30 cm. A plurality of reflecting elements are periodically arranged. That is, a plurality of unit structures having a plurality of cell regions with different reflection phases of electromagnetic waves are arranged. It is divided into three divided regions, and two sub-regions are arranged symmetrically on either side of the main region. In the above model, the reflection direction vector of the electromagnetic wave in each divided region was designed to obtain an irradiation area with a half-width FWHM of 6.5° centered on the polar angle θ=27°. The simulation results are shown in FIG. 41. Note that this example was used as a reference example because the desired reflection beam profile could not be obtained.

[0419] [Rating 1] It was confirmed from Examples 1 to 3 that it is possible to widen the beam width of the reflected wave by the entire frequency selective reflector by appropriately arranging a plurality of divided regions whose reflection direction vectors of the electromagnetic wave are subtly different from one another.

[0420] In addition, when the size of each divided region is large as in Example 2, the reflected beam profile tends to be disturbed and the side lobes also tend to be large, but by reducing the size of each divided region as in Example 1 and by gently changing the reflection direction vector of the electromagnetic wave in each divided region, it was found that a stable and broad main beam is easily obtained. In addition, when the size of the frequency selective reflector is small as in Example 3 and Reference Example 1, the main beam tends to be broad from the beginning, but similar to the case of the frequency selective reflector being large as in Examples 1 and 2, it was found that the reflected beam profile is easily stabilized by reducing the size of each divided region as in Example 3 and by gently changing the reflection direction vector of the electromagnetic wave in each divided region. In addition, in Reference Example 1, the size of the frequency selective reflector is small and the number of divided regions is small, so interference occurs, and sharp drops occur on both sides of the polar angle θ=27°, and the desired reflected beam profile was not obtained. From these results, it was shown that it is effective to increase the number of divided regions and divide the divided regions more finely.

[0421] In Comparative Example 1, we tried to widen the reflected beam by changing the reflection phase of each cell region with a variable with a standard deviation of 60%, but the reflected beam did not widen. This is presumably because we were unable to form an orderly wavefront.

[0422] [Reference example 2] A simulation was performed on the reflection characteristics of a frequency selective reflector. In the simulation, the unit structure of the dielectric layer had a thickness distribution in which the thickness increased in one direction as shown in Fig. 42(a), and had six cell regions of different thicknesses, and the dielectric layer was modeled to have a periodic structure in which the unit structures were repeatedly arranged in one direction. In the simulation, the reflecting member was modeled as having ring-shaped reflecting elements regularly arranged, which resonated at the frequency of the incident wave and reflected the electromagnetic wave of that frequency. In the simulation, the following parameters were used.

[0423] Incident wave frequency: 28GHz Incident wave angle: 0 degrees, -10 degrees Desired reflection angle of reflected wave: 27 degrees, 37 degrees Relative reflection phase difference between adjacent cell areas: 60 degrees

[0424] The simulation results are shown in Figure 42(b). When the incident angle is 0 degrees, that is, the reflection for incidence from the front direction 31 is shown by the solid line indicated with reference numeral 32, and when the incident angle is -10 degrees, that is, the reflection for incidence from the -10 degree direction 33 is shown by the solid line indicated with reference numeral 34. It can be seen that when the incident angle is 0 degrees, reflection occurs in the +27 degree direction from the regular reflection direction, and when the incident angle is -10 degrees, reflection occurs in the +37 degree direction from the regular reflection direction.

[0425] [Reference example 3] A simulation was performed on the reflection characteristics of a frequency selective reflector. In the simulation, the unit structure of the dielectric layer had a thickness distribution in which the thickness increased in one direction as shown in Fig. 43(a), and had 10 cell regions of different thicknesses, and the dielectric layer was modeled to have a periodic structure in which the unit structures were repeatedly arranged in one direction. In the simulation, the reflecting member was modeled as having ring-shaped reflecting elements regularly arranged, which resonated at the frequency of the incident wave and reflected the electromagnetic wave of that frequency. In the simulation, the following parameters were used.

[0426] Incident wave frequency: 28GHz Incident wave angle: 0 degrees Desired reflection angle of reflected wave: 16 degrees Relative reflection phase difference between adjacent cell areas: 36 degrees

[0427] The simulation results are shown in Figure 43(b). When the incident angle is 0 degrees, that is, when incident from the front direction 35, the reflection is shown by the solid line indicated by the reference symbol 36. It can be seen that when the incident angle is 0 degrees, the light is reflected in a direction of +16 degrees from the regular reflection direction. Also, in Figure 43(b), the reflection direction is closer to the regular reflection direction compared to Figure 42(b). This is because the unit structure of the dielectric layer has 6 cell regions in Figure 42(a) but 10 cell regions in Figure 43(a), and the length of the unit structure in a given direction in which the thickness increases is longer.

[0428] [Reference example 4] First, a reflective member in which ring-shaped reflective elements were regularly arranged was produced by etching a PET film with copper foil in accordance with the model of the reflective member in Reference Example 2. In addition, a dielectric layer was formed by a 3D printer in accordance with the model of the dielectric layer in Reference Example 2. Next, the dielectric layer was attached onto the reflective member to produce a frequency selective reflector.

[0429] The reflection characteristics of the frequency selective reflector were measured using a compact range measurement system and a network analyzer. The reflection characteristics of the frequency selective reflector of Reference Example 4 were almost identical to the simulation results of Reference Example 2.

[0430] [Reference example 5] In the analysis of the reflectarray, the reflection phase was calculated for a frequency selective reflector having a reflecting member with a frequency selective surface (FSS) and a dielectric layer using a general transmission line equivalent circuit as shown in Fig. 44. The symbols in Fig. 44 are as follows. ZVAC: A transmission line with a characteristic impedance of air. The length of the line is the length obtained by subtracting the thickness of the dielectric layer from the phase observation plane set at an arbitrary distance from the top surface of the dielectric layer. ZPC: A transmission line with a characteristic impedance of a dielectric layer. The line length is the thickness of the dielectric layer h. r: indicates the resistance of the ring-shaped reflective element of the FSS. L: indicates the inductance of the ring-shaped reflecting element of the FSS. C: The capacitance of the ring-shaped reflecting element of the FSS is shown. ZPET: This shows a transmission line with the dielectric constant of the dielectric substrate on which the FSS ring-shaped reflecting element is placed. The line length is the thickness of the dielectric substrate. ZL: Indicates the characteristic impedance of the space (air) on the back side of the dielectric substrate.

[0431] As a result, it was calculated that the reflection phase change due to the resonance frequency shift caused by stacking dielectric layers of different thicknesses is at most a few tens of degrees, which is about 25% of the maximum reflection phase of 360 degrees, and the rest of the reflection phase change is due to wavelength shortening within the dielectric layer. Furthermore, even if the position of the reflective member with the frequency-selective surface and the dielectric layer is misaligned, the misalignment will be uniform throughout the frequency-selective reflector, but considering that the reflection phase with adjacent cell areas only needs to be uniform in order for the reflected wave to be a plane wave, it was concluded that there is almost no effect on the reflection direction.

[0432] [Examples 4 to 9] As shown in Fig. 31 and Figs. 45 to 49, a frequency selective reflector in which nine types of cell regions with different reflection phases of electromagnetic waves are repeatedly arranged was designed by simulation. In the nine types of cell regions, the reflection phase of the electromagnetic wave in the cell region with the largest advance in the reflection phase of the electromagnetic wave is taken as a reference, and the relative reflection phase of the electromagnetic wave in each cell region is set to more than -360 degrees and less than 0 degrees, for example, 0 degrees, -40 degrees, -80 degrees, -120 degrees, -160 degrees, -200 degrees, -240 degrees, -280 degrees, and -320 degrees in descending order. In Fig. 31 and Figs. 45 to 49, the cell regions are numbered 0, 1, 2, 3, 4, 5, 6, 7, and 8 in descending order of the relative reflection phase of the electromagnetic wave in each cell region.

[0433] Example 4 shown in FIG. 31 is designed to reflect an incident wave from a finite distance in the (θ,φ)≈(28,0) [degree] direction in the (θ,φ)≈(5,170) [degree] direction.

[0434] In the fifth embodiment shown in FIG. 45, an incident wave from a finite distance in the (θ,φ) ≒ (3,0) [degree] direction is designed to be reflected with a spread centered on the (θ,φ) ≒ (7,0) [degree] direction.

[0435] Example 6 shown in FIG. 46 is designed to reflect an incident wave from a finite distance in the (θ,φ) ≈ (27,5) [degree] direction with a spread centered on the (θ,φ) ≈ (9,160) [degree] direction.

[0436] Example 7 shown in Figure 47 is designed to reflect an incident wave from a finite distance in the (θ,φ) ≈ (27,5) [degree] direction with a spread centered on the (θ,φ) ≈ (20,170) [degree] direction.

[0437] In the eighth embodiment shown in FIG. 48, an incident wave from (x, y, z) = (5, 0, 10) [m] is designed to be reflected toward (x, y, z) = (-2, 0, 20) [m] with a narrower beam width.

[0438] Example 9 shown in Figure 49 is designed to reflect an incident wave from a finite distance in the (θ,φ) ≒ (3,45) [degree] direction with a large horizontal spread centered on the (θ,φ) ≒ (0,0) [degree] direction.

[0439] In all of Examples 4 to 9, the boundary portion where the gradually decreasing relative reflection phase of the electromagnetic wave suddenly increases was not branched but was a continuous curve.

[0440] [Example 10] Two types of frequency selective reflectors that reflect electromagnetic waves in the 28 GHz band were prepared. Figures 50(a) to (c) show the reflection characteristics of the frequency selective reflector 1A. As shown in Figure 50(b), the horizontal direction had an incident angle of 59° and a reflection angle of -5±2°. As shown in Figure 50(c), the vertical direction had an incident angle of 0° and a reflection angle of +1±1°. In this way, the frequency selective reflector 1A was designed so that the reflected beam would not spread too much. Figures 51(a) to (c) show the reflection characteristics of the frequency selective reflector 1B. As shown in Figure 51(b), the horizontal direction had an incident angle of 46° and a reflection angle of -4±6.5°. As shown in Figure 51(c), the vertical direction had an incident angle of 1° and a reflection angle of -9±1°. In this way, the frequency selective reflector 1B was designed so that the reflected beam would spread by ±6.5° in the horizontal direction. Both frequency selective reflectors were designed with spherical waves in mind. Frequency selective reflector 1A was A0 paper size, and frequency selective reflector 1B was A2 paper size.

[0441] The two frequency selective reflectors 1A and 1B were arranged as shown in FIG. 34(a). The installation positions and angles of the two frequency selective reflectors 1A and 1B were set so that the electromagnetic waves from the base station 41 would be reflected by the two frequency selective reflectors 1A and 1B in turn and reach the coverage hole 42. FIG. 34(b) is an enlarged view of FIG. 34(a). Since the reflected beam from the frequency selective reflector 1B is designed to spread at ±6.5°, the measurement positions A to F were set so as to cross the reflected beam width direction. In FIG. 34(b), the reference numeral 60 indicates the reflected beam width.

[0442] [Reference example 6] The same procedure was followed as in Example 10, except that the frequency selective reflector 1B was not used.

[0443] [Rating 2] The communication environment was confirmed by using a local 5G-compatible smart device (FCNT FMP181L) and measuring the download speed from the server with a speed check app at each measurement location A to F. The ratio of the download speed at each measurement location A to F to the download speed in front of the base station was then calculated.

[0444] The results are shown in Figure 52. In Reference Example 6, the download speed at each of measurement positions A to F was 0.42 to 0.56 times the download speed in front of the base station. In contrast, in Example 10, the download speed was faster at measurement positions B to F compared to Reference Example 6. This confirmed an improvement in the communication environment. Furthermore, in Example 10, the download speed at measurement position D was almost the same as in front of the base station.

[0445] Furthermore, in Example 10, no improvement in the communication environment was observed by installing the frequency selective reflector 1B at measurement position A, which was located outside the reflected beam width 60. Moreover, the improvement in the communication environment was small at measurement position F, which was close to the edge of the reflected beam width 60. From this, it was confirmed that the reflected beam from the frequency selective reflector 1B was reflected with a reflected beam profile almost as designed.

[0446] This disclosure provides the following [1] to

[22] . [1] A frequency selective reflector that reflects electromagnetic waves in a specific frequency band in a direction other than the regular reflection direction, It has multiple regions, A frequency selective reflector with the ability to adjust the reflected beam profile. [2] The entire surface of the frequency selective reflector is divided into a plurality of divided regions; the plurality of divided regions include a main region which is a divided region located at the center of the frequency selective reflector, and a plurality of sub-regions which are divided regions other than the main region, the plurality of sub-regions are arranged around the main region; The reflection direction vectors of the electromagnetic waves in the divided regions are different from each other, A frequency selective reflector as described in [1], wherein the reflection direction vector of the electromagnetic wave in each of the sub-regions is set to expand outward from the reflection direction vector of the electromagnetic wave in the main region as the center. [3] The entire surface of the frequency selective reflector is divided into a plurality of divided regions; The reflection direction vectors of the electromagnetic waves in the divided regions are different from each other, The frequency selective reflector described in [1], wherein the reflection direction vector of the electromagnetic wave in each of the divided regions is set to expand outward from a main reflection direction vector of the electromagnetic wave, which is derived from the sum of the reflection direction vectors of the electromagnetic wave in each of the divided regions. [4] The entire surface of the frequency selective reflector is divided into a plurality of divided regions; the plurality of divided regions include a main region which is a divided region located at the center of the frequency selective reflector, and a plurality of sub-regions which are divided regions other than the main region, the plurality of sub-regions are arranged around the main region; The reflection direction vectors of the electromagnetic waves in the divided regions are different from each other, The frequency selective reflector of [1], wherein the reflection direction vector of the electromagnetic wave in each of the sub-regions is set to converge inward around the reflection direction vector of the electromagnetic wave in the main region. [5] The entire surface of the frequency selective reflector is divided into a plurality of divided regions; The reflection direction vectors of the electromagnetic waves in the divided regions are different from each other, The frequency selective reflector described in [1], wherein the reflection direction vector of the electromagnetic wave in each of the divided regions is set to converge inward around a main reflection direction vector of the electromagnetic wave, which is derived from the sum of the reflection direction vectors of the electromagnetic wave in each of the divided regions. [6] A frequency selective reflector according to any one of [1] to [5], wherein the angle between the reflection direction vectors of the electromagnetic waves between adjacent divided regions is within 15°. [7] A frequency selective reflector as described in [2], [4] or [6], in which the half-width of the reflected beam profile is within 40° in a graph in which the horizontal axis represents the deviation angle from the reflection direction vector of the electromagnetic wave in the main region and the vertical axis represents the reflection intensity of the electromagnetic wave of the frequency selective reflector. [8] A frequency selective reflector according to [3], [5] or [6], in which the half-width of the reflected beam profile is within 40° in a graph in which the horizontal axis represents the deviation angle from the main reflection direction vector of the electromagnetic wave and the vertical axis represents the reflection intensity of the electromagnetic wave of the frequency selective reflector. [9] The frequency selective reflector according to [2] or [3], wherein the area S1 of the frequency selective reflector satisfies the following formula (1). S1 ≧ S0 × Sr1 / Sr0 (1) (In formula (1), S1 is the area of ​​the frequency selective reflector (m 2 ), Sr1 is the solid angle of the reflected beam that satisfies the desired reception range of the electromagnetic wave, and S0 is the area (m 2 ), and Sr0 represents the solid angle of the reflected beam by a frequency selective reflector having an area of ​​S0 when the frequency selective reflector does not have the above-mentioned divided regions.

[10] A frequency selective reflector described in any of [2] to [9], in which a plurality of unit structures each having a plurality of cell regions with different reflection phases of the electromagnetic wave are arranged, and each of the divided regions has at least one of the cell regions.

[11] The frequency selective reflector is A reflecting member that reflects the electromagnetic wave; a dielectric layer that is disposed on an incident side of the electromagnetic wave with respect to the reflecting member, has a concavo-convex structure in which a plurality of unit structures having a thickness distribution in which the thickness increases in a predetermined direction are disposed, and transmits the electromagnetic wave; The unit structure of the dielectric layer has a plurality of cell regions having different thicknesses, For each unit structure of the dielectric layer, the horizontal axis represents the length of the unit structure in the specified direction, and the vertical axis represents the relative reflection phase when the electromagnetic wave passes through the dielectric layer, is reflected by the reflecting member, passes through the dielectric layer again, and is emitted to the incident side of the electromagnetic wave. The value of the relative reflection phase of the electromagnetic wave is greater than -360 degrees and less than 0 degrees. On this graph, points corresponding to the center position in the specified direction of each cell region and the relative reflection phase of the electromagnetic wave in each cell region are plotted, and when a straight line passing through the point corresponding to the minimum thickness cell region having the minimum thickness is drawn, each point is on the same straight line, the dielectric layer has, as the unit structure, at least a first unit structure having three or more of the cell regions having different thicknesses; A frequency selective reflector according to any one of [2] to

[10] , which controls the reflection direction of the electromagnetic wave by controlling the relative reflection phase distribution of the electromagnetic wave through the thickness distribution of the dielectric layer.

[12] The frequency selective reflector according to

[11] , wherein the reflecting member is a frequency selective plate that reflects only the electromagnetic wave.

[13] The frequency selective reflector according to

[12] , wherein the reflecting member has a reflection phase control function for controlling the reflection phase of the electromagnetic wave.

[14] The frequency selective reflector has a reflecting member that reflects the electromagnetic wave, The frequency selective reflector according to any one of [2] to

[10] , wherein the reflecting member has a reflection phase control function for controlling the reflection phase of the electromagnetic wave.

[15] A frequency selective reflector that reflects electromagnetic waves of a specific frequency band in a direction other than the regular reflection direction, A plurality of cell regions having different reflection phases of the electromagnetic waves are repeatedly arranged, The frequency selective reflector according to [1], wherein when the relative reflection phase of the electromagnetic wave in each cell region is set to greater than -360 degrees and less than 0 degrees based on the reflection phase of the electromagnetic wave in the cell region where the delay in the reflection phase of the electromagnetic wave is the largest, the boundary portion where the relative reflection phase of the electromagnetic wave, which gradually decreases, suddenly increases is not branched but is a continuous curve.

[16] The frequency selective reflector includes a reflecting member that reflects the electromagnetic wave, and a dielectric layer that is disposed on an ...

Claims

1. A frequency selective reflector that reflects electromagnetic waves in a specific frequency band in a direction different from the specular reflection direction, a plurality of cell regions each having a different reflection phase of the electromagnetic wave are repeatedly arranged, and the cell regions are arranged in a lattice pattern; The cell region has one reflective element disposed therein, The boundary portion, where the gradually increasing size of the reflective element suddenly decreases, is not branched but is a continuous curved line; A frequency selective reflector in which the entire surface of the frequency selective reflector is divided into a plurality of virtual divided areas, and when the size of the virtual divided areas is the size of the cell area, the reflection direction vector of the electromagnetic wave in each cell area spreads outward from the main reflection direction vector of the electromagnetic wave, which is derived from the sum of the reflection direction vectors of the electromagnetic wave in each cell area.

2. A frequency selective reflector that reflects electromagnetic waves in a specific frequency band in a direction different from the specular reflection direction, a plurality of cell regions each having a different reflection phase of the electromagnetic wave are repeatedly arranged, and the cell regions are arranged in a lattice pattern; The cell region has one reflective element disposed therein, The boundary portion, where the gradually increasing size of the reflective element suddenly decreases, is not branched but is a continuous curved line; A frequency selective reflector in which the entire surface of the frequency selective reflector is divided into a plurality of virtual divided areas, and when the size of the virtual divided areas is the size of the cell area, the reflection direction vector of the electromagnetic wave in each of the cell areas converges inward around the main reflection direction vector of the electromagnetic wave, which is derived from the sum of the reflection direction vectors of the electromagnetic wave in each of the cell areas.

3. A frequency selective reflector that reflects electromagnetic waves in a specific frequency band in a direction different from the specular reflection direction, a plurality of cell regions each having a different reflection phase of the electromagnetic wave are repeatedly arranged, and the cell regions are arranged in a lattice pattern; The cell region has one reflective element disposed therein, The boundary portion, where the gradually increasing size of the reflective element suddenly decreases, is not branched but is a continuous curved line; When the entire surface of the frequency selective reflector is divided into a plurality of virtual divided regions and the size of the virtual divided regions is the size of the cell region, The reflection direction vector of the electromagnetic wave in each cell area spreads outward in the horizontal direction from a main reflection direction vector of the electromagnetic wave, which is derived from the sum of the reflection direction vectors of the electromagnetic wave in each cell area, or A frequency selective reflector in which the reflection direction vector of the electromagnetic wave in each cell area spreads outward in the vertical direction, with the main reflection direction vector of the electromagnetic wave, which is derived from the sum of the reflection direction vectors of the electromagnetic wave in each cell area, as the center.

4. A frequency selective reflector that reflects electromagnetic waves in a specific frequency band in a direction different from the specular reflection direction, a plurality of cell regions each having a different reflection phase of the electromagnetic wave are repeatedly arranged, and the cell regions are arranged in a lattice pattern; The cell region has one reflective element disposed therein, The boundary portion, where the gradually increasing size of the reflective element suddenly decreases, is not branched but is a continuous curved line; The reflection direction vector of the electromagnetic wave in each cell area is determined based on the relationship with other adjacent cell areas, and the frequency selective reflector spreads outward from the main reflection direction vector of the electromagnetic wave, which is derived from the sum of the reflection direction vectors of the electromagnetic wave in each cell area.

5. A frequency selective reflector that reflects electromagnetic waves in a specific frequency band in a direction different from the specular reflection direction, a plurality of cell regions each having a different reflection phase of the electromagnetic wave are repeatedly arranged, and the cell regions are arranged in a lattice pattern; The cell region has one reflective element disposed therein, The boundary portion, where the gradually increasing size of the reflective element suddenly decreases, is not branched but is a continuous curved line; A frequency selective reflector in which the reflection direction vector of the electromagnetic wave in each cell area is determined based on the relationship with other adjacent cell areas, and converges inward around the main reflection direction vector of the electromagnetic wave, which is derived from the sum of the reflection direction vectors of the electromagnetic wave in each cell area.

6. A frequency selective reflector that reflects electromagnetic waves in a specific frequency band in a direction different from the specular reflection direction, a plurality of cell regions each having a different reflection phase of the electromagnetic wave are repeatedly arranged, and the cell regions are arranged in a lattice pattern; The cell region has one reflective element disposed therein, The boundary portion, where the gradually increasing size of the reflective element suddenly decreases, is not branched but is a continuous curved line; a reflection direction vector of the electromagnetic wave in each cell area is determined based on a relationship with other adjacent cell areas; The reflection direction vector of the electromagnetic wave in each cell area spreads outward in the horizontal direction from a main reflection direction vector of the electromagnetic wave, which is derived from the sum of the reflection direction vectors of the electromagnetic wave in each cell area, or A frequency selective reflector in which the reflection direction vector of the electromagnetic wave in each cell area spreads outward in the vertical direction, with the main reflection direction vector of the electromagnetic wave, which is derived from the sum of the reflection direction vectors of the electromagnetic wave in each cell area, as the center.

7. A frequency selective reflector described in any of claims 1 to 6, wherein the incident direction vectors of the electromagnetic waves in each cell area are different from each other.

8. The reflection direction vector of the electromagnetic wave in each of the cell regions spreads outward in the horizontal direction, centered on a main reflection direction vector of the electromagnetic wave, which is derived from the sum of the reflection direction vectors of the electromagnetic wave in each of the cell regions, and converges inward in the vertical direction, centered on a main reflection direction vector of the electromagnetic wave, which is derived from the sum of the reflection direction vectors of the electromagnetic wave in each of the cell regions, or 7. A frequency selective reflector according to claim 3, wherein the reflection direction vectors of the electromagnetic waves in each of the cell regions spread outward in the vertical direction, centered on a main reflection direction vector of the electromagnetic waves, which is derived from the sum of the reflection direction vectors of the electromagnetic waves in each of the cell regions, and converge inward in the horizontal direction, centered on the main reflection direction vector of the electromagnetic waves, which is derived from the sum of the reflection direction vectors of the electromagnetic waves in each of the cell regions.

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