Reflection array, reflection array device and design method of reflection array

Abstract

The purpose of the present invention is to provide a technique for improving the yield. A representative reflective array according to the present invention is a reflective array in which at least an element pattern, a dielectric layer, and a ground layer are laminated in this order, and is characterized in that the reflective array includes at least one reflection control region having at least two unit cells in which one of the element patterns is disposed, and in that the dielectric layer is disposed in the at least two unit cells, and the ground layer is disposed in the at least two unit cells. The element pattern includes a cross-shaped patch in which two square patches are orthogonal on an xy plane, and in the reflection control region, a first element width wx, which is a width in the x-axis direction of the element pattern, and / or a second element width wy, which is a width in the y-axis direction, differ for each of the element patterns disposed in the at least two unit cells.

Description

Technical Field

[0001] The present invention relates to a reflective array, a reflective array device and a reflective array design method. Background Art

[0002] With the advancement of digitalization in society, data transmission speeds in wireless communications have dramatically increased, and this has led to an increase in the frequency of electromagnetic waves. However, as the frequency of electromagnetic waves increases, their rectilinear propagation improves. This prevents electromagnetic waves from passing through shadows of buildings, etc., creating areas where communication is impossible, known as blind spots.

[0003] For these reasons, achieving wide-area 5G and 6G communications requires increasing the number of base stations. However, the enormous cost of adding base stations makes it difficult to increase the number of base stations in the short term. In recent years, to address these challenges, attention has focused on technologies that control the direction of electromagnetic waves.

[0004] Among such technologies, a reflective plate using a cross-shaped reflective element has been developed. Patent Document 1 discloses the following.

[0005] The metasurface reflector comprises: a dielectric substrate; a metal ground layer, which is arranged on the bottom surface of the dielectric substrate so that polarized waves in all directions do not pass through the metasurface reflector; and

[0006] Multiple supercells are provided, each comprising two or more cross-shaped metal resonators having different arm lengths. The supercells comprising the metal resonators are formed on the upper surface of a dielectric substrate and are periodically arranged in a diffraction grating. The diffraction grating reflects vertically and horizontally polarized incident waves and reflects electromagnetic waves of a specified frequency in an anomalous manner with a desired phase.

[0007] In addition, Patent Document 2 discloses the following.

[0008] For a reflection array in which multiple reflection elements are arranged on a substrate and reflect a first polarized wave having an electric field component parallel to the surface of the substrate and a second polarized wave having an electric field component perpendicular to the surface in a first desired direction and a second desired direction, respectively, the multiple reflection elements each have a patch set separately from the floor, and the gap between the patches of the reflection elements adjacent in the first axis direction is set to a value corresponding to the location of the gap, so that the first polarized wave is reflected with a specified reflection phase, and the gap between the patches of the reflection elements adjacent in the second axis direction perpendicular to the first axis is set to a value corresponding to the location of the gap, so that the second polarized wave is reflected with a specified reflection phase.

[0009] Patent Document 1: Japanese Patent Application Laid-Open No. 2021-48465

[0010] Patent Document 2: Japanese Patent No. 5469724 Summary of the Invention

[0011] In a reflect array having a cross-shaped element pattern, if dimensional errors occur in the element pattern, the reflection phase of each region tends to vary significantly from the design value, and the reflection intensity in a desired direction may decrease.

[0012] Therefore, there is a problem that it is difficult to improve the yield rate of reflect arrays.

[0013] Furthermore, neither Patent Documents 1 nor 2 sufficiently studies the method of setting design parameters.

[0014] Therefore, an object of the present invention is to provide a technology for improving the yield rate of reflect arrays.

[0015] In order to solve the above-mentioned problems, one of the representative reflection arrays of the present invention is a reflection array obtained by stacking at least an element pattern, a dielectric layer, and a ground layer in sequence, characterized in that the reflection array includes at least one reflection control area, the reflection control area has at least two unit cells, and one element pattern is arranged in the unit cell, and the element pattern includes two cross patches with two square patches orthogonal to each other on the xy plane. Within the reflection control area, the width of the element pattern in the x-axis direction, i.e., the first element width wx, and / or the width in the y-axis direction, i.e., the second element width wy, are different for each element pattern respectively arranged in the at least two unit cells.

[0016] Effects of the Invention

[0017] According to the present invention, a technique for improving the yield rate of reflect arrays can be provided.

[0018] Other problems, structures, and effects than those described above will become clear from the description of the following embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a diagram showing the structure of a reflect array.

[0020] Figure 2 This is a diagram showing an example of the configuration of functional layers.

[0021] Figure 3 It is a diagram showing another example of the configuration of the functional layers.

[0022] Figure 4 This is a diagram showing an example of the arrangement of unit cells corresponding to the direction in which asymmetric reflection occurs.

[0023] Figure 5This is a diagram showing an example of the arrangement of unit cells corresponding to the direction in which asymmetric reflection occurs.

[0024] Figure 6 This is a diagram showing an example of the arrangement of unit cells corresponding to the direction in which asymmetric reflection occurs.

[0025] Figure 7 It is a diagram showing the structure of a device pattern.

[0026] Figure 8 This is a diagram showing an example of a reflection control area.

[0027] Figure 9 This is a diagram showing a state where the element length in the x-axis direction and the element length in the y-axis direction are changed within the reflection control region.

[0028] Figure 10 It is a diagram showing examples of element pattern shapes and the width of each element pattern.

[0029] Figure 11 A diagram showing an example of the shape of a device pattern after etching.

[0030] Figure 12 This is a diagram showing the structure of the reflect array described in Example 1 on the xy plane.

[0031] Figure 13 This is a graph showing the analysis result of the unit cell in the design process of Comparative Example 1, and illustrates the reflection phase when the element width of the element pattern is set to wx=wy=9.000 mm and the element length 1 is changed.

[0032] Figure 14 1 is an analysis result of the reflect array obtained in Comparative Example 1, and is a graph showing the reflection characteristics of the reflect array with and without dimensional errors on the xz plane.

[0033] Figure 15 1 is an analysis result of the unit cell in the design process of Example 1, and is a diagram showing the reflection phase when the element length of the element pattern is set to lx=ly=15.000 mm and the element width w is changed.

[0034] Figure 16 1 and 2 are analysis results of the reflect array obtained in Example 1, and are diagrams showing reflection patterns of the reflect array with and without dimensional errors on the xz plane.

[0035] Figure 17 This is a result of analyzing the unit cell in the design process of Comparative Example 2, and is a diagram showing the reflection phase when the element width of the element pattern is set to wx=wy=1.000 mm and the element length 1 is changed.

[0036] Figure 18 1 is an analysis result of the reflect array obtained in Comparative Example 2, and is a graph showing the reflection characteristics of the reflect array with and without dimensional errors on the xz plane.

[0037] Figure 19 1 is an analysis result of the unit cell in the design process of Example 2, and is a diagram showing the reflection phase when the element length of the element pattern is set to lx=ly=3.250 mm and the element width w is changed.

[0038] Figure 20 1 and 2 are analysis results of the reflect array obtained in Example 2, and are diagrams showing reflection patterns of the reflect array with and without dimensional errors on the xz plane.

[0039] Figure 21 This is a graph showing the analysis result of the unit cell in the design process of Comparative Example 3, and illustrates the reflection phase when the element width of the element pattern is set to wx=wy=0.500 mm and the element length 1 is changed.

[0040] Figure 22 1 and 2 are analysis results of the reflect array obtained in Comparative Example 3, and are graphs showing the reflection characteristics of the reflect array with and without dimensional errors on the xz plane.

[0041] Figure 23 1 is an analysis result of the unit cell in the design process of Example 3, and is a diagram showing the reflection phase when the element length of the element pattern is set to lx=ly=1.700 mm and the element width w is changed.

[0042] Figure 24 1 and 2 are analysis results of the reflect array obtained in Example 3, and are diagrams showing reflection patterns of the reflect array with and without dimensional errors on the xz plane.

[0043] Figure 25 This is a graph showing the analysis result of the unit cell in the design process of Comparative Example 4, and illustrates the reflection phase when the element width of the element pattern is set to wx=wy=0.400 mm and the element width 1 is changed.

[0044] Figure 26 1 and 2 are analysis results of the reflect array 6 obtained in Comparative Example 4, and are graphs showing the reflection characteristics of the reflect array with and without dimensional errors on the xz plane.

[0045] Figure 27 1 is an analysis result of the unit cell in the design process of Example 4, and is a diagram showing the reflection phase when the element length of the element pattern is set to lx=ly=0.900 mm and the element width w is changed.

[0046] Figure 28 1 and 2 are analysis results of the reflect array obtained in Example 4, and are diagrams showing reflection patterns of the reflect array with and without dimensional errors on the xz plane.

[0047] Figure 29 1 is an analysis result of the reflect array obtained in Example 5, and is a diagram showing the reflection characteristics of the reflect array on the xz plane.

[0048] Figure 30 1 is an analysis result of the reflect array obtained in Example 6, and is a diagram showing the reflection characteristics of the reflect array on the xz plane.

[0049] Figure 31 1 is an analysis result of the reflect array obtained in Example 7, and is a diagram showing the reflection characteristics of the reflect array on the xz plane. DETAILED DESCRIPTION

[0050] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to these embodiments. In the description of the accompanying drawings, the same reference numerals are used to indicate the same parts.

[0051] When there are a plurality of components having the same or similar functions, different superscripts may be assigned to the same reference numerals for description. In addition, when there is no need to distinguish the plurality of components, superscripts may be omitted for description.

[0052] For ease of understanding of the invention, the positions, sizes, shapes, and ranges of the components shown in the drawings may not be shown in their actual positions, sizes, shapes, and ranges. Therefore, the present invention is not necessarily limited to the positions, sizes, shapes, and ranges disclosed in the drawings.

[0053] (Explanation of terms)

[0054] In the present invention, a "reflectarray (electromagnetic wave reflector)" is a component that reflects electromagnetic waves. This is not limited to structures that perform symmetrical reflection, where the incident and reflection angles are equal. It also includes structures that perform asymmetrical reflection, where the incident and reflection angles differ, structures that scatter electromagnetic waves in multiple directions, and structures that focus electromagnetic waves at specific locations. In the following description, an xyz coordinate system is used, and the reflectarray is arranged on the xy plane.

[0055] The term "reflection control region" refers to a portion of a region constituting a reflect array. The reflection control region is the minimum region capable of reflecting electromagnetic waves incident thereon in a predetermined direction.

[0056] Furthermore, a reflect array is formed by combining one or more reflection control regions. In the case of a reflection control region, in addition to a two-dimensional region where electromagnetic waves are in a direction parallel to the incident region, it also includes a layer structure formed in a direction perpendicular to the region.

[0057] In addition, a "unit cell" refers to a region obtained by dividing the reflection control region. A unit cell includes one element pattern.

[0058] In addition, "θi" represents the angle of incidence of the incident wave. Let the angle of incidence in the x-axis direction be θix, and the angle of incidence in the y-axis direction be θiy. In addition, "θr" represents the angle of reflection of the reflected wave. Let the angle of reflection in the x-axis direction be θrx, and the angle of reflection in the y-axis direction be θry.

[0059] Furthermore, regarding the angle θx in the x-axis direction, a positive angle (0° to 180°) indicates a direction extending from the +z-axis direction toward the +x-axis direction, and a negative angle (0° to -180°) indicates a direction extending from the +z-axis direction toward the -x-axis direction. Similarly, regarding the angle θy in the y-axis direction, a positive angle (0° to 180°) indicates a direction extending from the +z-axis direction toward the +y-axis direction, and a negative angle (0° to -180°) indicates a direction extending from the +z-axis direction toward the -y-axis direction.

[0060] In addition, regarding the element length, the element length in the x-axis direction is represented by lx, and the element length in the y-axis direction is represented by ly. In addition, regarding the element width, the element width in the x-axis direction is represented by wx, and the element width in the y-axis direction is represented by wy.

[0061] [First embodiment]

[0062] (Structure of reflect array)

[0063] Reference Figure 1 The structure of the reflect array and the structure of the element pattern will be described. Figure 1 This figure shows the structure of a reflectarray 6. Reflectarray 6 can periodically arrange multiple element patterns on a plane, allowing the direction of reflected waves to be set to a desired value. Reflectarray 6 includes at least element patterns (elements) 1, a dielectric layer 2, and a ground layer (ground) 3. In the following description, an xyz coordinate system is used, and reflectarray 6 is arranged on the xy plane.

[0064] Figure 1 The reflect array 6 is a structure that generates predetermined asymmetric reflection of electromagnetic waves along the x-axis. Figure 1 When the reflective array 6 has a structure in which a plurality of reflection control regions are arranged in the x-axis direction and the y-axis direction, the reflection control region 5 is the same as the reflection control region 5. Figure 1In the embodiment, the reflection control region 5 is represented by a solid line, taking the reflection control region included in the reflection array 6 as a representative. The reflection control region 5 includes unit cells 41, 42, 43, ... 4 n (Hereinafter, when describing without specifying a unit unit, it is also referred to as "unit unit 4". n is a positive integer greater than or equal to 2.) Unit unit 4 is a portion obtained by dividing the reflection control region 5 at equal intervals along the x-axis direction. n is the number of divisions when the reflection control region is divided into unit units in the x-axis direction. When the x-axis dimension (length) of the unit unit 4 is sx, the y-axis dimension is sy, the x-axis dimension of the reflection control region 5 is Lx, and the y-axis dimension is Ly, sx = Lx / n, sy = Ly. In addition, Figure 1 , the reflection control region 5 is shown to be composed of n unit cells 4 arranged in the x-axis direction, and the reflect array 6 includes a plurality of reflection control regions 5. However, the present invention is not limited to such a structure. The reflection control region may be composed of unit cells arranged in the y-axis, or may include unit cells arranged in both the x-axis and the y-axis. The structure of the reflection control region will be described later.

[0065] (Structure of device pattern)

[0066] The element pattern is formed on the surface of the unit cell 4 facing the +z axis direction. The number of divisions n is expressed as unit cell 41, unit cell 42, ... unit cell 4. n The element pattern 11 is formed in the unit cell 41. The element pattern 12 is formed in the unit cell 42. The element pattern 13 is formed in the unit cell 43. n Element pattern 1 is formed n .

[0067] Furthermore, within the reflection control region and between adjacent regions of the same reflection control region, the element patterns are arranged at equal intervals. Specifically, for each element pattern within the reflection control region 5, when the size of the closest interval between adjacent element patterns in the x-axis direction (hereinafter also referred to as "gap") is set to gx, within the reflection control region 5, the element patterns 11 to 1 n In addition, the element pattern 1 of the reflection control area 5 is arranged at equal intervals of gx. n and a reflection control region 5x (shown by a dotted line, including a region where the element pattern 1 is formed) adjacent to the reflection control region 5 in the x-axis direction. x Unit 1 of 4 x 1. Component pattern 1 is formed x 2 units of unit 4 x 2. ...a device pattern 1 is formed x nUnit cell 4 x n ) component pattern 1 x When the gap between 1 is Gx, Figure 1 In this case, Gx and gx are equal.

[0068] Furthermore, the element pattern of the reflection control region 5 and the reflection control region 5y adjacent to the reflection control region 5 in the y-axis direction (shown by a dotted line, including the element pattern 1) are formed. y Unit 1 of 4 y 1. Component pattern 1 is formed y 2 units of unit 4 y 2. ...a device pattern 1 is formed y n Unit cell 4 y n ) between the component patterns in Figure 1 It is uniform in the medium and is expressed in Gy.

[0069] In the reflection control area, each element pattern has a slightly different shape from other element patterns. Here, element pattern 11 to element pattern 1 n The shape of the element pattern shown is called a cross patch. A cross patch is a shape in which two square patches are orthogonal to each other on the xy plane. The element pattern 11 has the following shape, that is, a square patch having a dimension in the x-axis direction, i.e., an element length lx1, and a dimension in the y-axis direction, i.e., an element width wy1, and a square patch having a dimension in the y-axis direction, i.e., an element length ly1, and a dimension in the x-axis direction, i.e., an element width wx1, share a common center of gravity and are orthogonal to each other. Similarly, the element pattern 1 n The shape is such that a square patch with an element length of lxn and an element width of wyn and a square patch with an element length of lyn and an element width of wxn share the same center of gravity and intersect orthogonally. The method for setting the element length and element width will be described later.

[0070] (Description of each structure and design method)

[0071] (Layer Structure)

[0072] Reference Figure 2 as well as Figure 3 The layer structure of the reflect array 6 will be described. Figure 2 as well as Figure 3is a diagram showing an example of the layer structure of the reflectarray 6. The reflectarray 6 has a structure in which at least an element pattern 1, a dielectric layer 2, and a ground layer 3 are stacked in a direction from the +z-axis direction toward the -z-axis direction. In the following description, the structure consisting of the three layers of the element pattern 1, the dielectric layer 2, and the ground layer 3 is referred to as the "basic structure." From a practical point of view, it is preferred that the reflectarray 6 stack a single layer or multiple layers having various functionalities (hereinafter also referred to as "functional layers") on the element pattern 1 side or the ground layer 3 side, or both sides of the basic structure. In the following description, layers other than the element pattern 1, the dielectric layer 2, and the ground layer 3 included in the reflectarray are sometimes referred to as "functional layers" when the type of layer is not specified.

[0073] If necessary, a layer for improving the adhesion between the element pattern 1 and the dielectric layer 2, or between the ground layer 3 and the dielectric layer 2, may be formed. Furthermore, a layer for purposes other than improving adhesion may also be formed. Furthermore, intermediate products generated during the manufacturing process of the reflect array 6 are formed in layers and may remain in the reflect array 6.

[0074] As functional layers, for example, there are an appearance layer that is designed in consideration of the landscape of the place where the reflective array 6 is installed, a setting layer for making it easy to install the reflective array 6 on a support body such as a wall or a top surface, a protective layer for protecting the basic structure, and an adhesive layer for stacking the layers.

[0075] Figure 2 1 is a diagram showing an example of the configuration of the functional layer 7. As for the stacking method of stacking toward the element pattern 1 side, the functional layer 7 can be stacked as in the reflect array 6a so as to fill the gaps between the plurality of element patterns 1 ( Figure 2 (a)), the functional layer 7 can be stacked like the reflective array 6b so as to contact the upper surface of the element pattern 1 while maintaining gaps between the plurality of element patterns 1 ( Figure 2 (b)), the functional layer 7 may be stacked as in the reflective array 6c so as not to contact the upper surface of the element pattern 1 ( Figure 2 (c)). Furthermore, when reflect arrays 6a to 6c share a common structure other than functional layer 7, reflect arrays 6a to 6c each have different reflective characteristics. Therefore, by changing the stacking method of functional layer 7, the characteristics of the reflect array can be changed.

[0076] Figure 3 is a diagram showing another example of the configuration of the functional layer. Figure 3 , an arrangement example of a protective layer 8, an adhesive layer 9, an exterior layer 10, and a setting layer 11 is shown as functional layers. Figure 3(a) shows a reflect array 6d, which has a protective layer 8 stacked to cover the element pattern 1 and the ground layer 3, and further has an exterior layer 10 on the element pattern 1 side with an adhesive layer 9 interposed therebetween, and has a setting layer 11 on the ground layer side with an adhesive layer 9 interposed therebetween. Figure 3 (b) shows a reflective array 6e, which includes a setting layer 11 on the ground layer side via an adhesive layer 9, and an exterior layer 10 on the element pattern 1 side via a gap.

[0077] (Reflection Control Area)

[0078] The reflect array 6 includes at least one reflection control area. Depending on the method of configuring the reflection control area, the properties of the reflect array can be changed. For example, when an electromagnetic wave of a certain wavelength is incident at a certain angle of incidence, by periodically configuring reflection control areas with a common reflection direction, the reflect array can be given the characteristic of reflecting in a single direction. In addition, when an electromagnetic wave of a certain wavelength is incident at a certain angle of incidence, by configuring a reflect array including reflection control areas with different reflection directions, the characteristic of scattering the electromagnetic wave in multiple directions can be given. In addition, by setting a structure in which the reflection direction is offset by a predetermined angle for each reflection control area, the characteristic of converging the electromagnetic waves at a specific location can also be given. During design, the frequency to be applied to the reflect array is set as the following "operating frequency".

[0079] The dimension Lx of the reflection control area in the x-axis direction is determined, for example, by formula (1) when the wavelength of the operating frequency is set to λ, the x-axis component of the incident angle of the electromagnetic wave incident on the reflection control area is set to θix, the x-axis component of the reflection angle of the electromagnetic wave reflected from the reflection control area is set to θrx, and θix≠-θrx.

[0080] [Formula 1]

[0081]

[0082] In addition, for the y-axis dimension Ly of the reflection control area, when the y-axis component of the incident angle of the electromagnetic wave incident on the reflection control area is set to θiy, and the y-axis component of the reflection angle of the electromagnetic wave reflected from the reflection control area is set to θry, and θiy≠-θry, it is determined by, for example, formula (2).

[0083] [Formula 2]

[0084]

[0085] (Relationship between unit cell and reflection phase)

[0086] Reference Figures 4 to 6, the relationship between the unit cell and the reflection phase is explained. Figures 4 to 6 : is a diagram showing an example of the configuration of the unit cell corresponding to the direction in which the asymmetric reflection occurs. The reflection control region 5 has at least two unit cells. Here, Figure 4 (a) shows the direction of the electromagnetic wave incident on the reflect array 6f (incident wave) and the direction of the electromagnetic wave reflected from the reflect array 6f (reflected wave). In other words, the arrows drawn with thick solid lines show the direction of travel of the wavefront. The arrows toward the reflect array 6f show the direction of travel of the wavefront of the incident wave, and the arrows away from the reflect array 6f show the direction of travel of the wavefront of the reflected wave. Figure 4 (b) is a plan view of the reflective array 6f as viewed from the z-axis direction. Figure 5 as well as Figure 6 (a) and (b) are also related to Figure 4 The relationship between (a) and (b) is the same.

[0087] The unit cell has the function of reflecting incident electromagnetic waves with a predetermined phase difference. Within the reflection control region, each unit cell exhibits a different reflection phase. As a result, the wavefront of the reflected wave generated from the reflection control region, known as the reflected wavefront, is tilted relative to the reflection angle when the incident and reflection angles are equal. This results in asymmetric reflection, which is different from symmetric reflection when the incident and reflection angles are equal.

[0088] In the case where the reflective array 6f is intended to perform asymmetric reflection only along the x-axis direction (e.g. Figure 4 (a) θix≠-θrx), the unit cells showing different reflection phases are arranged along the x-axis direction in the reflection control region 5a ( Figure 4 (b)). The reflection control area 5a is set to have a division number n = 3 and has 3 unit cells arranged in the x-axis direction. The size Lx of the reflection control area 5a in the x-axis direction is determined by formula (1), and the size of the unit cell in the x-axis direction is Lx / 3. As represented by this example, when the y-axis component of the reflection angle is a symmetric reflection (θiy = -θry), Ly does not need to be determined by formula (2) and can take any value. However, from the perspective of ease of design, for convenience, it is set to use a square unit cell whose size is determined by Lx and the division number n, and Ly is equal to Lx / 3.

[0089] Similarly, if the reflective array 6g is intended to perform asymmetric reflection only along the y-axis direction (e.g. Figure 5 (a) θiy≠-θry), the unit cells showing different reflection phases are arranged along the y-axis direction in the reflection control region 5b ( Figure 5(b)). Here, m (m is a positive integer greater than or equal to 2) is set as the number of divisions when the reflection control area is divided into unit cells in the y-axis direction. The reflection control area 5b is set to have a division number m=3 and has 3 unit cells arranged in the y-axis direction. The size Ly of the reflection control area 5b in the y-axis direction is determined by formula (2), and the size of the unit cell in the y-axis direction is Ly / 3. The x-axis component of the reflection angle is a symmetrical reflection, so Lx does not need to be determined by formula (1) and can take any value. However, from the perspective of ease of design, for convenience, a square unit cell whose size is determined by Ly and the division number m is used, and Lx is equal to Ly / 3.

[0090] Figure 6 (a) shows the relationship between the reflective array and the electromagnetic wave, Figure 6 (a1) represents the case where the electromagnetic wave is projected onto the zx plane. Figure 6 (a2) represents the case where the electromagnetic wave is projected onto the zy plane. If it is desired to make the reflective array 6h also perform asymmetric reflection in any direction of the x-axis and y-axis directions (e.g. Figure 6 (a1) shows that θix≠-θrx and as Figure 6 (a2) shows that θiy≠-θry), a unit cell with different reflection phases in the x-axis direction is configured in the reflection control region 5c, and a unit cell with different reflection phases in the y-axis direction is also configured ( Figure 6 (b)). The reflection control area 5c includes 9 unit cells arranged in the x-axis direction and 3 unit cells arranged in the y-axis direction. The number of divisions of the reflection control area 5c can also be expressed as 3×3=9 using the number of divisions n=3 in the x-axis direction and the number of divisions m=3 in the y-axis direction. The size Lx in the x-axis direction of the reflection control area 5c is determined by formula (1), and the size Ly in the y-axis direction is determined by formula (2). The size of the unit cell in the x-axis direction is determined by Lx and n, and is Lx / 3. The size of the unit cell in the y-axis direction is determined by Ly and m, and is Ly / 3. Both the x-axis component and the y-axis component of the incident wave are asymmetrically reflected. Therefore, the x-axis component of the traveling direction of the reflected wavefront is different from the x-axis component of the traveling direction of the incident wavefront, and the y-axis component of the traveling direction of the reflected wavefront is different from the y-axis component of the traveling direction of the incident wavefront ( Figure 6 (a)).

[0091] Furthermore, gx represents the x-axis gap between the element patterns within the reflection control region 5c. Gy represents the y-axis gap between the element patterns within the reflection control region 5c. The x-axis gaps gx between the element patterns are equal, and the y-axis gaps gy between the element patterns are equal. Although gx and gy are shown as different, they may also be equal.

[0092] In addition, Gx represents the gap between the element pattern of the reflection control region 5c and the element pattern of the reflection control region adjacent to the reflection control region 5c in the x-axis direction. Gy represents the gap between the element pattern of the reflection control region 5c and the element pattern of the reflection control region adjacent to the reflection control region 5c in the y-axis direction. When the reflection control region identical to the reflection control region 5c is adjacent to the reflection control region 5c in the y-axis direction (or x-axis direction) without changing its position in the x-axis direction (or y-axis direction), gx and Gx are equal, and gy and Gy are equal.

[0093] (Distribution of reflection phase and surface impedance within the reflection control area)

[0094] The distribution of the reflection phase in the reflection control area is determined, for example, according to equations (3) and (4). Here, the wavelength of the operating frequency is set to λ(m), the x-axis component of the incident angle of the electromagnetic wave incident on the reflection control area is set to θix, the y-axis component is set to θiy, the x-axis component of the reflection angle of the electromagnetic wave reflected from the reflection control area is set to θrx, the y-axis component is set to θry, and the reflection phases of arbitrary coordinates x1 and x2 parallel to the x-axis in the reflection control area are set to The distance between coordinates x1 and x2 is dx, and the reflection phase difference between Φx1 and Φx2 is ΔΦx. In addition, the reflection phases of arbitrary coordinates y1 and y2 parallel to the y axis are respectively When the reflection control region is intended to perform asymmetric reflection along the x-axis, it is preferable to satisfy equation (3). When the reflection control region is intended to perform asymmetric reflection along the y-axis, it is preferable to satisfy equation (4). In addition, when the reflection control region is intended to perform asymmetric reflection in both the x-axis and y-axis directions, it is preferable to further satisfy either equation (3) or equation (4).

[0095] [Formula 3]

[0096]

[0097] [Formula 4]

[0098]

[0099] In addition, the distribution of surface impedance can also be applied to the reflection control area instead of the reflection phase. In this case, the distribution of surface impedance is expressed by, for example, equations (5) and (6). Here, Zsx is the surface impedance distribution of the reflection control area parallel to the x-axis direction, Zsy is the surface impedance distribution of the reflection control area parallel to the y-axis direction, and η1 is set to the impedance of the incident wave. In addition, the x-axis component of the incident angle of the electromagnetic wave incident on the reflection control area is set to θix, and the y-axis component is set to θiy. The x-axis component of the reflection angle of the electromagnetic wave reflected from the reflection control area is set to θrx, and the y-axis component is set to θry.

[0100] Furthermore, x1 and x2 represent relative x coordinates within the reflection control area, and the reference x = 0 can be set at any coordinate in the reflection control area. Similarly, y1 and y2 represent relative y coordinates within the reflection control area, and the reference y = 0 can be set at any coordinate in the reflection control area.

[0101] In addition, k1 is the wave number of the reflected wave. j represents an imaginary unit. When it is desired to make the reflection control area perform asymmetric reflection along the x-axis direction, it is preferable to satisfy equation (5). When it is desired to make the reflection control area perform asymmetric reflection along the y-axis direction, it is preferable to satisfy equation (6). In addition, when it is desired to make the reflection control area perform asymmetric reflection in any direction of the x-axis direction and the y-axis direction, it is preferable to satisfy both equations (5) and (6).

[0102] [Formula 5]

[0103]

[0104] [Formula 6]

[0105]

[0106] As other surface impedance distributions, for example, they are represented by equations (7) and (8). When it is desired that the reflection control region perform asymmetric reflection only along the x-axis direction, it is preferable to satisfy equation (7). When it is desired that the reflection control region perform asymmetric reflection only along the y-axis direction, it is preferable to satisfy equation (8). Furthermore, when it is desired that the reflection control region perform asymmetric reflection in both the x-axis direction and the y-axis direction, it is preferable to satisfy both equations (7) and (8).

[0107] [Formula 7]

[0108]

[0109] [Formula 8]

[0110]

[0111] Furthermore, the above equations (3) to (8) represent examples of design equations used when designing the distribution of the reflection phase and the distribution of the surface impedance. The present invention is not limited to the use of the above equations (3) to (8), and other design equations may be appropriately selected.

[0112] (Component pattern)

[0113] Reference Figure 1 、 Figures 7 to 10 , explaining the details of the element pattern. Generally, reflectarrays utilize resonance based on the element pattern to change the reflection characteristics. Here, linear or rectangular element patterns (square patches) primarily resonate polarized waves along their long axis. Therefore, using an element pattern shaped to orthogonally intersect these polarizations allows for both TE and TM polarizations.

[0114] In the reflectarray of the present invention, as the number of divisions n and m of the reflection control region increases, the size of each unit cell and the size of the element pattern decrease. Resonance occurs only when the element pattern size remains constant relative to the frequency. Therefore, increasing n and m above a certain value makes it difficult to achieve asymmetric reflection at the operating frequency. On the other hand, increasing n and m further allows for more control over the reflection characteristics of each smaller region, resulting in a reflectarray with reflection characteristics approaching theoretical characteristics.

[0115] Regarding the element pattern of the reflect array of the present invention, a cross patch having a shape in which two square patches are orthogonal to each other on the xy plane is included in the shape of the element pattern. Figure 1 As shown, the square patches that form the cross patch, each with its long side in the x-axis direction, have a long side dimension (element length lx) and a short side dimension (element width wy), while the square patches with its long side in the y-axis direction have a long side dimension (element length ly) and a short side dimension (element width wx). Therefore, the element pattern of unit cell 4n can be displayed with element lengths lxn and lyn, and element widths wxn and wyn.

[0116] Figure 7 This is a diagram showing the structure of the element pattern. One element pattern is configured in the unit cell. For the cross patch of the element pattern constituting the unit cell 4, the position where the two square patches intersect can be the same as the center of gravity of the unit cell ( Figure 7 (a) of the unit cell 4a), can also be different ( Figure 7 (b) unit cell 4b, Figure 7 (c) Unit cell 4c). The deformation of the cross patch can be selected appropriately to improve the flexibility and expandability of the design.

[0117] In the present invention, element widths wx and wy are treated as design parameters, and each element pattern included in the reflection control region is designed to have a different element width. The element width wx can vary within a range up to a value equal to the element length lx, and the element width wy can vary within a range up to a value equal to the element length ly. The element widths wx and wy within the same element pattern can be equal or different. When set to different values, the characteristics for TE and TM polarizations can be independently controlled.

[0118] Figure 8 is a diagram showing an example of a reflection control area. Figure 8 (a) shows an example of a case where the element widths wx and wy are equal in the same element pattern. Figure 8 (b) shows an example of a case where the element widths wx and wy are different. In this example, the following case is shown, that is, n=3, the element pattern shape is composed of only two square patches orthogonal to each other, and lx and ly are equal. On the other hand, in the reflection control area, the width of the element pattern in the x-axis direction, i.e., the first element width wx, and / or the width in the y-axis direction, i.e., the second element width wy, are different for each element pattern respectively configured in the unit cell. Detailed description Figure 8 ,exist Figure 8 In the reflection control region 5d of (a), the element width wx1 in the x-axis direction of the element pattern 1d1 is equal to the element width wy1 in the y-axis direction. The element width wx2 in the x-axis direction of the element pattern 1d2 is equal to the element width wy2 in the y-axis direction. The element width wx3 in the x-axis direction of the element pattern 1d3 is equal to the element width wy3 in the y-axis direction. On the other hand, in Figure 8 In the reflection control region 5e of (b), the element pattern 1e1 has an element width wx1 in the x-axis direction that is smaller than the element width wy1 in the y-axis direction. The element pattern 1e2 has an element width wx2 in the x-axis direction that is larger than the element width wy2 in the y-axis direction. The element pattern 1e3 has an element width wx3 in the x-axis direction that is larger than the element width wy3 in the y-axis direction.

[0119] In the reflection control region described so far, the element length lx in the x-axis direction is equal for each element pattern, and the element length ly in the y-axis direction is equal for each element pattern. Here, lx and ly can be equal or different. When lx and ly are different, characteristics for TE and TM polarization waves can be independently imparted to the element patterns.

[0120] Figure 9 A diagram showing a case where the element length in the x-axis direction and the element length in the y-axis direction are changed within the reflection control region. Figure 9(a) shows an example of the case where lx and ly are equal. Figure 9 (b) shows an example of the case where lx>ly, Figure 9 (c) shows an example of the case where lx<ly. In this example, n=3, the element pattern shape is composed of only two square patches orthogonal to each other, and wx and wy are equal in the same element pattern. Specifically, Figure 9 In the reflection control region 5f of (a), any element pattern has an element length lx in the x-axis direction and an element length ly in the y-axis direction. Figure 9 (b) the reflection control area 5g and Figure 9 In the reflection control region 5h of (c), the element lengths lx and ly are also shared between the element patterns.

[0121] Regarding the gap, the following examples are given: the case where only gx is equal between the element patterns within the reflection control area, the case where only gy is equal between the element patterns within the reflection control area, the case where gx and gy are respectively equal between the element patterns within the reflection control area and gx≠gy, and the case where gx and gy are respectively equal between the element patterns within the reflection control area and gx=gy.

[0122] Figure 10 It is a diagram showing examples of element pattern shapes and the width of each element pattern. Figure 10 (a) is the element pattern 1a with square patches orthogonal to each other. Figure 10 (b) is a device pattern 1b in the shape of what is generally called a Jerusalem Cross. Figure 10 (c) is configured with Figure 10 Element pattern 1c is a circular ring surrounded by the shape of (a). As shown in element patterns 1a to 1c, the two square patches share a common center of gravity and are orthogonal to each other. The shape of the element pattern in the xy plane is line symmetric with respect to the x-axis and y-axis. Furthermore, while the element patterns share a common center of gravity and are orthogonal to each other, the present invention is not limited to this. The two square patches can be orthogonal to each other without sharing a common center of gravity.

[0123] (Manufacturing Method)

[0124] The main manufacturing method for the basic structure of a reflective array is to form an element pattern by cutting or etching a copper foil laminate or a dielectric layer used as a printed circuit board, etc., wherein the dielectric layer is a dielectric layer formed with a metal film on one or both sides of the dielectric layer by dry coating such as evaporation or sputtering, electroplating, wet coating, etc.

[0125] Specifically, a copper foil laminate is formed by stretching and laminating copper foil onto an insulator, such as a glass cross, impregnated with a resin such as epoxy. The copper foil laminate has a plate-like shape, with copper foil stretched and laminated onto both sides of the plate-like insulator. The copper foil on one side serves as the component pattern 1, while the copper foil on the other side serves as the ground layer 3. The insulator corresponds to the dielectric layer 2.

[0126] When the metal film is formed on both surfaces of the dielectric, the element pattern 1 is formed from the metal film on one side, and the metal film on the other side is applied to the ground layer 3. The dielectric becomes the dielectric layer 2.

[0127] Figure 11 A diagram showing an example of the shape of a device pattern after etching. Figure 11 (a) shows a plan view of the element pattern 1, Figure 11 (b) to Figure 11 (d) shows a cross-sectional view of the element pattern 1. Figure 11 As shown in (a), the element pattern 1 is formed by a square patch having an element length lx and an element width wy, and a square patch having an element length ly and an element width wx, which are perpendicular to each other. For the etching method, either dry etching or wet etching can be used. When the etching method is used, rounded corners may appear in the element pattern 1 ( Figure 11 (a)), pinhole. In addition, it is assumed that the cross section of the element pattern 1 forms a positive tapered ( Figure 11 (b)), inverted cone ( Figure 11 (c)), arc shape ( Figure 11 (d)). Figure 11 In the example, the thickness of the element pattern 1 is t. When etching is used, the cross-sectional shape of the element pattern is preferably a shape that expands downward in the -z-axis direction, that is, a forward tapered shape. This forward tapered shape increases the surface area of ​​the element pattern, which improves adhesion to the functional layer described later when it is laminated.

[0128] In addition, due to the materials and manufacturing process, the reflect array, which is the final product, may be warped with a curvature radius of approximately R = 10 m.

[0129] Even when the above-mentioned shape change occurs, if the direction of the main beam changes by ±5°, the reflective characteristics of the reflect array are acceptable.

[0130] Furthermore, generally, in the case of cutting, the dimensional error of the device pattern is approximately ±100 μm, and in the case of etching, the dimensional error of the device pattern is approximately ±50 μm.

[0131] Other manufacturing methods include directly forming a device pattern or ground layer on a dielectric layer. The device pattern can also be formed by printing using relief printing, lithography, gravure printing, stencil printing, transfer printing, or the like. Alternatively, the device pattern can be formed by masking the dielectric layer with masking tape, masking agent, or the like, except for the device pattern, and then dry coating, electroplating, painting, or sputtering.

[0132] For lamination of other layers of the basic structure (functional layer 7 such as protective layer 8, adhesive layer 9, appearance layer 10, setting layer 11, etc.), pasting, printing, coating, and extrusion molding can be cited. For pasting, for example, dry lamination, wet lamination, hot lamination, and extrusion lamination are cited, but are not limited to these.

[0133] If a large reflect array is required, multiple reflect arrays can be arranged to form a single reflect array. In this case, during setup, assume that the reflect arrays are offset in the x-axis direction, offset in the y-axis direction, and have a gap of approximately 5 mm between them. Furthermore, assume that the reflect arrays are offset in a direction rotated approximately 5° in the xy plane.

[0134] Even when the above-mentioned changes occur, if the direction of the main beam changes by ±5°, the reflective characteristics of the reflect array are acceptable.

[0135] (Component pattern)

[0136] The surface resistance value of the element pattern is preferably less than or equal to 100Ω / □ (ohm per square). As materials for the element pattern, conductive materials such as inorganic oxide materials, metal materials, and conductive organic materials can be used. For example, as inorganic oxide materials and metal materials, indium tin oxide (ITO), indium zinc oxide (IZO), aluminum zinc oxide (AZO), gallium zinc oxide (GZO), antimony tin oxide, Ag, Al, Au, Pt, Pd, Cu, Co, Cr, In, Ag-Cu, Cu-Au, and Ni can be used. In addition, nanoparticles or nanowires containing at least one of the above materials can also be used. As conductive organic materials, polythiophene derivatives, polyacetylene derivatives, polyaniline derivatives, polypyrrole derivatives, carbon nanotubes, graphene, etc. are mentioned. In particular, from the viewpoints of material cost, conductivity, and film forming properties, Cu and Al are preferred. In addition, transparent reflective arrays can be produced by using materials such as ITO, a mixture of polyethylene dioxythiophene (PEDOT), and polystyrene sulfonic acid (PSS) (PEDOT / PSS). The thickness of the element pattern is, for example, greater than or equal to 10 nm and less than or equal to 18 μm. Based on flexibility, film forming properties, stability, sheet resistance, and low cost, it is preferred to use a thin film formed by vapor deposition as the element pattern.

[0137] The material of the element pattern can be the same as that of the ground layer, or a different material can be used. In addition, for example, at least one layer of the ground layer or the element pattern can also be formed of Cu or Al. Cu can reduce conductor loss due to its excellent conductivity. Al has a low density, light weight, and low cost, so it can form a lightweight and inexpensive reflective array. In addition, the thickness of at least one layer can be set to be less than or equal to 1 μm. By setting it to be less than or equal to 1 μm, the flexibility is improved, it becomes easier to set the reflective array on a curved surface, etc., and it can also achieve lightweighting.

[0138] Examples of forms using the above-mentioned material include a continuous film, a mesh shape, and a perforated shape.

[0139] When the element pattern is in a grid shape, the line width of the grid is preferably greater than or equal to 5 μm and less than or equal to 30 μm, more preferably greater than or equal to 6 μm and less than or equal to 15 μm. The line spacing of the grid is preferably greater than or equal to 50 μm and less than or equal to 500 μm, more preferably greater than or equal to 100 μm and less than or equal to 300 μm. In addition, when the wavelength at the operating frequency is set to λ, the line spacing of the grid is preferably less than or equal to 0.5×λ, more preferably less than or equal to 0.1×λ, and further preferably less than or equal to 0.01×λ. If the line spacing of the grid is less than or equal to 0.5×λ, performance can be ensured. In addition, the line spacing of the grid can be greater than or equal to 0.001×λ.

[0140] When the element pattern is in a grid shape and a transparent conductive material is used, the reflective array shows visible light transmittance, and can ensure a beautiful view after installation.

[0141] When the element pattern is in the form of a thin film, the flexibility of the reflective array can be improved, thereby enabling application to curved surfaces and roll-to-roll production processes.

[0142] When a thin film is used to form the element pattern, its thickness is preferably greater than the skin depth calculated according to equation (9): where d is the skin depth, ω is the angular frequency, μ is the magnetic permeability of the material, and σ is the electrical conductivity of the material.

[0143] [Formula 9]

[0144]

[0145] Furthermore, in order to improve the reflection efficiency of electromagnetic waves, it is necessary to reduce the loss caused by the element pattern. Therefore, it is preferable that the surface roughness of the element pattern is small.

[0146] (Dielectric layer)

[0147] For the dielectric layer, in addition to a single resin, a composite material such as paper, glass fiber, carbon fiber, etc. impregnated with a resin may be used.

[0148] Examples of monomeric resins include polyethylene (εr = 2.2 to 2.4), polypropylene (εr = 2.0 to 2.6), polystyrene (εr = 2.4 to 2.6), polyvinyl chloride (εr = 2.8 to 8.0), AS resin (εr = 2.6 to 3.1), ABS resin (εr = 2.4 to 4.1), polyethylene terephthalate (εr = 2.9 to 3.0), acrylic resin (εr = 2.7 to 4.5), polyurethane resin (εr = 4.0 to 7.1), epoxy resin (εr = 2 .5~6.0), nylon (εr=3.0~5.0), polyimide (εr=2.4~2.7), fluororesin (εr=2.0~2.6), polycarbonate (εr=2.9~8.9), polyphenylene ether (εr=2.8~8.2), polyphenylene sulfide (εr=3.2~4.6), polyvinylidene fluoride (εr=6.4~10.0), polyethylene naphthalate (εr=2.9), phenolic resin (εr=3.0~12.0), cycloolefin polymer (εr=2.3~2.5), etc. Here, εr represents the relative dielectric constant. In particular, polyethylene terephthalate (PET) is preferably used from the perspective of low cost and excellent versatility. In addition, the dielectric layer can also be set as a single layer or multiple layers. In addition, the dielectric layer can use a foam obtained by foaming the above materials. In addition, as the foam, it is preferred to use a foam with high flexibility.

[0149] Examples of the composite material include composite materials of paper / phenolic resin, paper / epoxy resin, glass / epoxy resin, and glass / fluororesin.

[0150] In addition, from the perspective of adjusting the dielectric constant, a combination of resin components or a mixture containing a dielectric compound and a resin component can be used. The relative dielectric constant of the mixture can be adjusted by selecting the dielectric compound and its content.

[0151] The relative dielectric constant of a mixture can be predicted using, for example, the Maxwell-Garnett equation. For a mixture of dielectric A with a relative dielectric constant εa and dielectric B with a relative dielectric constant εb, when the volume fraction of A is δa, the relative dielectric constant εm of the mixture is expressed by equation (10).

[0152] [Formula 10]

[0153]

[0154] Examples of the dielectric compound include barium titanate (εr=250 to 20,000), titanium dioxide (εr=83 to 183), lead zirconate titanate, strontium bismuth titanate, tantalum bismuth titanate, and bismuth ferrite.

[0155] When a transparent dielectric is used, the reflective array shows visible light transmittance, and a good view after installation can be ensured.

[0156] The relative dielectric constant of the dielectric layer is preferably in the range of greater than or equal to 1 and less than or equal to 20, more preferably in the range of greater than or equal to 1 and less than or equal to 10, and even more preferably in the range of greater than or equal to 2 and less than or equal to 4. If the relative dielectric constant is within this range, it is likely that the desired reflection phase characteristics will be easily obtained in the reflect array 1. In addition, the dielectric loss tangent is preferably in the range of greater than or equal to 0.00005 and less than or equal to 0.01, and more preferably in the range of greater than or equal to 0.00005 and less than or equal to 0.001. If it is within this range, a reflect array 1 with low dielectric loss can be produced.

[0157] The dielectric layer can be formed, for example, by wet coating methods such as die coating, comma coating, and gravure coating, melt extrusion methods such as T-die method and inflation method, calendaring film forming method, solution casting method, hot pressing method, etc. In addition, co-extrusion method can be used to extrude multiple resins in layers to form a thin film.

[0158] The thickness of the dielectric layer can be appropriately selected according to the design frequency. When the design frequency is set to 28 GHz, it is preferably greater than or equal to 40 μm and less than or equal to 250 μm, and more preferably greater than or equal to 50 μm and less than or equal to 200 μm. If it is too thin, it is difficult to ensure the reflection phase and it is difficult to design the reflect array 1. On the other hand, even if it is too thick, there is a tendency that it is difficult to ensure the reflection phase, the flexibility disappears, the total thickness of the reflect array becomes thicker, and it is difficult to save space. Therefore, it is preferred that the thickness of the dielectric layer is less than or equal to 250 μm. When the design frequency is set to 60 GHz, it is preferred that the thickness of the dielectric layer is greater than or equal to 10 μm and less than or equal to 250 μm. When the design frequency is greater than or equal to 100 GHz, it is easy to design the reflect array if the thickness of the dielectric layer is set to greater than or equal to a few μm and less than or equal to about 100 μm.

[0159] (Ground layer)

[0160] The ground layer is provided to reflect electromagnetic waves reaching the reflectarray. It also supports and protects the dielectric layer. Conductive materials such as inorganic oxides, metals, and conductive organic materials are used as the ground layer.

[0161] For example, as inorganic oxide materials and metal materials, indium tin oxide (ITO), indium zinc oxide (IZO), aluminum zinc oxide (AZO), gallium zinc oxide (GZO), antimony tin oxide, Ag, Al, Au, Pt, Pd, Cu, Co, Cr, In, Ag-Cu, Cu-Au and Ni can be used. In addition, nanoparticles or nanowires containing at least one of the above materials can be used. As conductive organic materials, polythiophene derivatives, polyacetylene derivatives, polyaniline derivatives, polypyrrole derivatives, carbon nanotubes, graphene and the like are mentioned. In particular, from the perspectives of material cost, conductivity and film forming properties, Cu and Al are preferred. In addition, in order to reflect electromagnetic waves, the surface resistance of the ground layer is preferably less than or equal to 100Ω / □. If this condition is met, a transparent reflective array can also be produced by using a mixture (PEDOT / PSS) of ITO, polyethylene dioxythiophene (PEDOT) and polystyrene sulfonic acid (PSS).

[0162] Examples of forms of using the above-mentioned material include a continuous film, a mesh shape, a perforated shape, and a periodic structure.

[0163] Here, the grid refers to a state in which mesh-like through-holes (openings) are formed on the plane of the conductor. When the conductor is formed in a grid shape, the mesh of the grid can be square or rhombus. When the mesh of the grid is formed in a square shape, the mesh of the preferred grid is square. If the mesh of the grid is square, the appearance is good. In addition, it can also be a random shape formed based on a self-assembly method. By being set to a random shape, moire fringes can be prevented. When metal is processed into a grid shape, methods such as perforation processing of a metal plate, etching of a metal plate, etc. can be adopted.

[0164] When the ground layer is in a grid shape and a transparent conductive material is used, the reflective array shows visible light transparency, and the landscape after installation can be ensured.

[0165] When the ground layer is in a grid shape, the line width of the grid is preferably greater than or equal to 5μm and less than or equal to 30μm, more preferably greater than or equal to 6μm and less than or equal to 15μm. The line spacing of the grid is preferably greater than or equal to 50μm and less than or equal to 500μm, more preferably greater than or equal to 100μm and less than or equal to 300μm. In addition, when the wavelength at the operating frequency is set to λ, the line spacing of the grid is preferably less than or equal to 0.5×λ, more preferably less than or equal to 0.1×λ, and further preferably less than or equal to 0.01×λ. If the line spacing of the grid is less than or equal to 0.5×λ, performance can be ensured. In addition, the line spacing of the grid can be greater than or equal to 0.001×λ.

[0166] As a method for forming the ground layer, if a metal material is used, dry coating such as sputtering and vapor deposition, wet coating such as gravure coating or die coating by ink-forming the metal material, and surface treatment such as electroplating can be selected. Alternatively, a ground layer obtained by rolling a metal plate can be used as the ground layer. If an inorganic oxide material is used, dry coating can be selected as the method for forming the ground layer 11. If an organic material is used, wet coating can be selected as the method for forming the ground layer 11. Alternatively, it can be formed by coating or spraying.

[0167] When the ground layer is a thin film formed by electroplating, vapor deposition, or the like, the flexibility of the reflect array can be improved, thereby enabling application to curved surfaces and roll-to-roll production processes.

[0168] When the ground layer is in the form of a thin film, it is preferable that the thickness thereof is larger than the skin depth calculated according to the formula (9) in the same manner as the element pattern.

[0169] Furthermore, in order to improve the reflection efficiency of electromagnetic waves, it is recommended to reduce the loss caused by the ground layer. Therefore, it is preferable that the surface roughness of the ground layer is small.

[0170] When the ground layer is a periodic structure, it is possible to selectively reflect or transmit specific frequencies. For example, when a structure with a patch-like conductive pattern periodically arranged is used as the ground layer, it is possible to reflect only specific frequencies, thereby providing the ability to transmit frequencies other than the operating frequency. Furthermore, when a structure is used in which areas without conductive material are periodically arranged as holes, it is possible to design a reflect array that asymmetrically reflects the operating frequency and transmits only specific frequencies.

[0171] (Support)

[0172] The reflective array is mounted on a support. The support can be a newly installed panel or pillar, or an existing signage, wall, ceiling, or the like. The support preferably has a mechanism for adjusting the reflective array's angle vertically or horizontally, and more preferably has a mechanism for moving the reflective array's position vertically or horizontally. The reflective array is mounted on a support and used as a reflective array device.

[0173] (Settings layer)

[0174] The mounting layer is used to secure the reflective array to the support. For example, if the adhesive layer, the adhesion layer, or the support is made of metal, magnets can be used. Using magnets makes it easier to change the position and angle of the reflective array.

[0175] (Appearance layer)

[0176] The exterior layer is used to give the reflective array surface an aesthetically pleasing appearance. For example, when used as a decorative architectural material like wallpaper, an exterior layer may be added to achieve harmony with the space. Alternatively, when used as a whiteboard, a functional film may be used as the exterior layer. The exterior layer may also be endowed with the functions of the protective layer, described later.

[0177] (Protective layer)

[0178] The protective layer may be a film or sheet having gas barrier properties, water vapor barrier properties, water resistance, wear resistance, and scratch resistance to prevent oxidative degradation, physical damage, and peeling of the device pattern and ground layer.

[0179] If the reflective array is to be used indoors, it is preferred to use a protective layer having antibacterial, antiviral, or anti-fouling properties. Furthermore, if the reflective array is to be used outdoors, a layer containing UVA (ultraviolet absorber) or HALS (light stabilizer) may be used to provide weather resistance.

[0180] [Evaluation Results (Example / Comparative Example)]

[0181] The results of Examples 1 to 4 and Comparative Examples 1 to 4 are summarized in Table 1, and the results of Examples 5 to 7 are summarized in Table 2.

[0182] In addition, Figure 12 1 is a diagram showing the structure on the xy plane of the reflect array of Example 1. The unit of the dimensions in the diagram is mm.

[0183] [Table 1]

[0184]

[0185] [Table 2]

[0186]

[0187] (Comparative Example 1)

[0188] Reflect array 6 has a basic structure in which 0.018 mm thick copper is used for element pattern 1 and ground layer 3, and a 1.564 mm thick glass / epoxy resin composite material is used for dielectric layer 2. The electrical conductivity of copper is set to 5.8 × 10^7 Siemens / meter (siemens / m), the real part of the relative permittivity of dielectric layer 2 is 4.5, and tanδ is set to 0.014.

[0189] The operating frequency is set to 4.85 GHz, the target reflection characteristics (set as the target reflection characteristics) are set to θix = -60°, θrx = 0°, θiy = θry = 0°, and the x-axis dimension Lx of the reflection control area 5 is determined to be 71.376 mm using formula (1).

[0190] The number of divisions of the reflection control region 5 is set to 3, and the dimensions of the unit cell in the x-axis and y-axis directions are set to 23.792 mm. The shape of the element pattern is set to a cross patch with two square patches orthogonal to each other in the xy plane. Here, in each element pattern within the reflection control region 5, only the element length is set to differ. Specifically, the element length is set to lx1 = ly1, lx2 = ly2, lx3 = ly3, and the element width is set to wx1 = wx2 = wx3 = wy1 = wy2 = wy3 = 9.000 mm.

[0191] In addition, in Tables 1 and 2, and in the figures and documents described later, the unit cells contained in the reflection control region 5 are represented as unit cell 1, unit cell 2, ... unit cell p (p is an integer greater than or equal to 1 and less than or equal to the number of divisions n). In unit cell p, the element length in the x-axis direction is set to lxp, the element length in the y-axis direction is set to lyp, the element width in the x-axis direction is set to wxp, and the element width in the y-axis direction is set to wyp. In the case where lxp and lyp are equal, the subscripts x and y are omitted. In the case where wxp and wyp are equal, the subscripts x and y are omitted. In the case where the unit cell is not specifically specified, the subscript p is sometimes omitted.

[0192] First, the reflection phase of the unit cell with respect to the element length 1 was analyzed using finite element analysis software (HFSS) manufactured by Ansys. Figure 13 This is the result of analyzing the unit cell in the design process of Example 1. It is a graph showing the reflection phase when the element width of the element pattern is set to wx = wy = 9.000 mm and the element length 1 is changed. The reflection phase changes as the element length 1 changes. In addition, Figure 13 In the figure, the element length 1 on the horizontal axis represents the element length lx in the x-axis direction and the element length ly in the y-axis direction. In the following description, the element length 1 and the reflection phase diagram are also shown in FIG. Figure 13 Same conditions.

[0193] Next, based on the unit cell analysis results, the element length l in each unit cell was determined in a manner consistent with the impedance distribution of equation (7). The element length 1 was set to lx1 = ly1 = 14.750 mm, lx2 = ly = 11.412 mm, and lx3 = ly3 = 15.237 mm. The element length 1 of each element pattern was determined to have no dimensional error.

[0194] Reflectarray 6 has 12 x 12 unit cells arranged in the x- and y-directions, with a size of 285.504 mm square in the xy plane. HFSS was used to analyze the reflection characteristics of reflectarray 6 when a polarized wave parallel to the y-axis with θix = -60° and θiy = 0° was incident on the array.

[0195] In order to understand the influence of dimensional errors on the reflection characteristics, a similar analysis was performed on the case where the element length 1 of each element pattern of the reflect array 6 was increased by 0.100 mm, assuming dimensional errors caused by cutting.

[0196] Figure 14 : is the analysis result of the reflect array 6 obtained in Comparative Example 1, and is a graph showing the reflection characteristics of the reflect array 6 with and without dimensional errors on the xz plane. Figure 14 The horizontal axis of the graph is the reflection angle θrx, and the vertical axis is the RCS (radar cross section). The RCS is essentially a value corresponding to the intensity of the reflected wave. For a reflectarray 6 without dimensional error, an electromagnetic wave incident at θix = -60° is reflected in the desired direction of θrx = 0°, resulting in an RCS of 7.06 dBsm. On the other hand, for a reflectarray 6 with dimensional error, although reflection occurs in the direction of θrx = 0°, the RCS is 6.87 dBsm, and the change in RCS due to the dimensional error is -0.18 dBsm.

[0197] (Example 1)

[0198] A reflectarray identical to the reflectarray described in Comparative Example 1 was prepared, except for the element pattern shape. The element pattern shape was such that only the element widths of the element patterns within the reflection control region 5 differed. Specifically, the element lengths of the element patterns were set to lx1 = lx2 = lx3 = ly1 = ly2 = ly3 = 15.000 mm, and the element widths within the same element pattern were set to wx1 = wy1, wx2 = wy2, and wx3 = wy3. HFSS was used to analyze the reflection phase of the unit cell relative to the element width w, as well as the reflection characteristics of the reflectarray 6 with and without dimensional errors.

[0199] Figure 15 This is the result of analyzing the unit cell in the design process of Example 1, and is a diagram showing the reflection phase when the element length of the element pattern is set to lx=ly=15.000mm and the element width w is changed. Figure 15 In the figure, the element width w on the horizontal axis represents the element width wx in the x-axis direction and the element width wy in the y-axis direction. In the following description, the element width w and the reflection phase diagram are also shown in FIG. Figure 15The same conditions. The reflection phase changes with the change of the element width. In addition, compared with the comparative example 1 in which the element length is changed, Figure 13 Compared to the case with the element width, the reflection phase tilts more gently with respect to the element width. For example, to change the reflection phase from 120° to -120°, the element length l in Comparative Example 1 needs to change by approximately 2.5 mm, between 13.5 mm and 16 mm. In contrast, in Example 1, the element length w needs to change by approximately 6 mm, between 5 mm and 11 mm. In other words, this means that when the same degree of dimensional error occurs, the present invention, which uses element width as a design parameter, results in a smaller change in the reflection phase within the unit cell. As a result, the change in the reflection characteristics of reflectarray 6 is reduced.

[0200] The element widths w are determined as wx1 = wy1 = 8.306 mm, wx2 = wy2 = 1.305 mm, and wx3 = wy3 = 9.608 mm. Figure 16 The following are the analysis results of reflectarray 6 obtained in Example 1, showing the reflection patterns of reflectarray 6 with and without dimensional errors on the xz plane. In the reflectarray 6 without dimensional errors, electromagnetic waves incident at θix = -60° are reflected in the desired direction of θrx = 0°, with an RCS of 7.03 dBsm. Furthermore, in the reflectarray 6 with dimensional errors, reflection in the direction of θrx = 0° is also produced, with an RCS of 7.02 dBsm. Therefore, the change in RCS due to dimensional error is -0.02 dBsm, which suppresses the decrease in reflection intensity due to dimensional error compared to the reflectarray 6 described in Comparative Example 1, which uses element length as a design parameter.

[0201] The design method will be specifically described. Here, a design method for a reflect array in which a plurality of identical reflection control regions are arranged in the x-axis direction and the y-axis direction will be described.

[0202] (Step 1) First, target reflection characteristics (operating frequency, incident angle, and reflection angle) are set.

[0203] (Step 2) Next, the dimensions Lx and Ly of the reflection control area are determined using equations (1) and (2). When asymmetric reflection is performed only in the x-axis direction, Lx is determined by equation (1), and Ly can be set to any desired dimensions. Alternatively, when asymmetric reflection is performed only in the y-axis direction, Ly is determined by equation (2), and Lx can be set to any desired dimensions.

[0204] (Step 3) Next, the size of the reflection control region Lx is divided into n parts, and Ly is divided into m parts. The size of the unit cell is determined.

[0205] (Step 4) Next, the element lengths lx and ly of the element patterns are determined within the unit cell. The element patterns are arranged uniformly and without deviation within the unit cell, so as a result, the gaps gx and gy between the element patterns are also determined.

[0206] (Step 5) Next, the reflection phase of the unit cell is analyzed using the element width w as a design parameter. Figure 15 As shown, the reflection phase is derived using the element widths wx and wy of the element pattern as design parameters, and an analysis result showing the relationship between the element width and the reflection phase in the unit cell is obtained.

[0207] (Step 6) Next, the ideal reflection phase or impedance for achieving the reflection characteristics of the target reflection control region is calculated using equations (3) to (8). Based on the analytical results, the element width w that achieves the desired reflection phase or impedance is selected. In Example 1, three element widths were selected, and a reflection control region consisting of three unit cells was set.

[0208] (Step 7) Next, a reflect array including at least one reflection control region is formed, and the reflection characteristics of the reflect array are analyzed.

[0209] (Step 8) In addition, based on the analysis results of Step 7, the element widths wx and wy can be further fine-tuned using an optimization method to make the RCS at the target reflection angle higher and the RCS outside the target angle smaller.

[0210] (Comparative Example 2)

[0211] Reflect array 6 has a basic structure in which 0.018 mm thick copper is used for element pattern 1 and ground layer 3, and a 0.764 mm thick glass / fluororesin composite material is used for dielectric layer 2. The electrical conductivity of copper is set to 5.8 × 10^7 Siemens / meter, the real part of the relative permittivity of dielectric layer 2 is set to 2.6, and tanδ is set to 0.0025.

[0212] The operating frequency is set to 27.2 GHz, the target reflection characteristics are set to θix=33°, θrx=0°, and θiy=θry=0°, and the dimension Lx of the reflection control region 5 in the x-axis direction is determined to be 20.238 mm using (1).

[0213] The number of divisions of the reflection control region 6 is set to 3, and the dimensions of the unit cell in the x-axis and y-axis directions are set to 6.746 mm. The shape of the element pattern is set to a cross patch with two square patches orthogonal to each other in the xy plane. Here, for each element pattern in the reflection control region 5, it is set that only the element length differs. Specifically, the element length is set to lx1 = ly1, lx2 = ly2, lx3 = ly3, and the element width is set to wx1 = wx2 = wx3 = wy1 = wy2 = wy3 = 1.000 mm.

[0214] First, HFSS was used to analyze the reflection phase of the unit cell relative to the element length 1. Figure 17 This is a graph showing the analysis results of the unit cell during the design process of Comparative Example 2, and illustrates the reflection phase when the element width of the element pattern is set to wx=wy=1.000 mm and the element length 1 is changed. The reflection phase changes as the element length changes.

[0215] Next, based on the unit cell analysis results, the element length l in each unit cell was determined in a manner consistent with the impedance distribution of equation (7). The element length l was set to lx1 = ly1 = 3.390 mm, lx2 = ly2 = 3.709 mm, and lx3 = ly3 = 3.067 mm. The element length l of each element pattern was determined to have no dimensional error.

[0216] Reflectarray 6 has 9 x 9 unit cells arranged in the x- and y-directions, with a size of 60.714 mm square in the xy plane. HFSS was used to analyze the reflection characteristics of reflectarray 6 when a polarized wave parallel to the y-axis with θix = 33° and θiy = 0° was irradiated.

[0217] In order to understand the influence of dimensional errors on the reflection characteristics, a similar analysis was performed on the case where the element length 1 of each element pattern of the reflect array 6 was increased by 0.100 mm, assuming dimensional errors caused by cutting.

[0218] Figure 18 The following are the analysis results of reflectarray 6 obtained in Comparative Example 2. These graphs show the reflection characteristics of reflectarray 6 with and without dimensional errors in the xz plane. For reflectarray 6 without dimensional errors, an electromagnetic wave incident at θix = 33° is reflected in the desired direction of θrx = 0°, resulting in an RCS of 0.22 dBsm. On the other hand, for reflectarray 6 with dimensional errors, although reflection occurs in the direction of θrx = 0°, the RCS is -0.71 dBsm. The change in RCS due to the dimensional errors is -0.94 dBsm.

[0219] (Example 2)

[0220] A reflectarray identical to the reflectarray described in Comparative Example 2 was prepared, except for the element pattern shape. The element pattern shape was such that only the element widths of the element patterns within the reflection control region 6 differed. Specifically, the element lengths of the element patterns were set to lx1 = lx2 = lx3 = ly1 = ly2 = ly3 = 3.250 mm, and the element widths were set to wx1 = wy1, wx2 = wy2, and wx3 = wy3. HFSS was used to analyze the reflection phase of the unit cell relative to the element width w, as well as the reflection characteristics of the reflectarray with and without dimensional errors.

[0221] Figure 19 This is the analysis result of the unit cell in the design process of Example 2. It shows the reflection phase when the element length of the element pattern is set to lx = ly = 3.250 mm and the element width w is changed. The reflection phase changes with the change of the element width. In addition, compared with the comparative example 2 in which the element length is changed, Figure 17 Compared to the case with the element width, the reflection phase tilts more gently with respect to the element width. For example, to change the reflection phase from 60° to -120°, the element length l in Comparative Example 2 needs to change by approximately 0.3mm, between 3.2mm and 3.5mm. In contrast, in Example 2, the element length w needs to change by approximately 1.8mm, between 0.6mm and 2.4mm. In other words, when the same degree of dimensional error occurs, Example 2, which uses element width as a design parameter, shows a smaller change in the reflection phase within the unit cell, resulting in a smaller change in the reflection characteristics of reflectarray 6.

[0222] The element widths are determined as wx1 = wy1 = 1.582 mm, wx2 = wy2 = 2.955 mm, and wx3 = wy3 = 0.319 mm. Figure 20 The following are the analysis results of reflectarray 6 obtained in Example 2, showing the reflection patterns of reflectarray 6 with and without dimensional errors on the xz plane. In the reflectarray 6 without dimensional errors, electromagnetic waves incident at θix = 33° are reflected in the desired direction of θrx = 0°, with an RCS of 0.26 dBsm. Furthermore, in the reflectarray 6 with dimensional errors, reflection in the direction of θrx = 0° is also produced, with an RCS of 0.18 dBsm. Therefore, the change in RCS due to dimensional error is -0.08 dBsm, which suppresses the decrease in reflection intensity due to dimensional error compared to the reflectarray 6 described in Comparative Example 2, which uses element length as a design parameter.

[0223] (Comparative Example 3)

[0224] Reflect array 6 has a basic structure using 0.018 mm thick copper for element pattern 1 and ground layer 3, and 0.200 mm thick PTFE for dielectric layer 2. The electrical conductivity of copper is set to 5.8 × 10^7 Siemens / meter, the real part of the relative permittivity of dielectric layer 2 is set to 2.06, and tanδ is set to 0.0007.

[0225] The operating frequency is set to 60 GHz, the target reflection characteristics are set to θix=0°, θrx=45°, and θiy=θry=0°, and the dimension Lx of the reflection control region 5 in the x-axis direction is determined to be 7.065 mm using Equation 1.

[0226] The number of divisions of the reflection control region 5 is set to 3, and the dimensions of the unit cell in the x-axis and y-axis directions are set to 2.355 mm. The shape of the element pattern is set to a cross patch with two square patches orthogonal to each other in the xy plane. Here, for each element pattern in the reflection control region 5, it is set that only the element width differs. Specifically, the element length is set to lx1 = ly1, lx2 = ly2, lx3 = ly3, and the element width is set to wx1 = wx2 = wx3 = wy1 = wy2 = wy3 = 0.500 mm.

[0227] First, HFSS was used to analyze the reflection phase of the unit cell relative to the element length 1. Figure 21 The diagram shows the analysis results of the unit cell during the design process of Comparative Example 3, and shows the reflection phase when the element width of the element pattern is set to wx=wy=0.500 mm and the element length 1 is changed. The reflection phase changes as the element length changes.

[0228] Next, based on the unit cell analysis results, the element length l in each unit cell was determined in a manner consistent with the impedance distribution of equation (7). The element length l was set to lx1 = ly1 = 1.844 mm, lx2 = ly2 = 1.581 mm, and lx3 = ly3 = 1.753 mm. The element length l of each element pattern was determined to have no dimensional error.

[0229] Reflectarray 6 has 27 x 27 unit cells arranged in the x- and y-directions, with a size of 63.585 mm square in the xy plane. HFSS was used to analyze the reflection characteristics of reflectarray 6 when a polarized wave parallel to the y-axis with θix = 0° and θiy = 0° was irradiated.

[0230] In order to understand the influence of dimensional errors on the reflection characteristics, the case where the element length 1 of each element pattern of the reflect array 6 was increased by 0.100 mm was also analyzed, assuming dimensional errors caused by cutting.

[0231] Figure 22 The following are the analysis results of reflectarray 6 obtained in Comparative Example 3. These graphs show the reflection characteristics of reflectarray 6 with and without dimensional errors in the xz plane. For the reflectarray 6 without dimensional errors, an electromagnetic wave incident at θix = 0° is reflected in the desired direction of θrx = 45°, resulting in an RCS of 7.40 dBsm. On the other hand, for the reflectarray with dimensional errors, although reflection occurs in the direction of θrx = 0°, the RCS is 5.12 dBsm, indicating a change in RCS of -2.28 dBsm due to the dimensional errors.

[0232] (Example 3)

[0233] A reflectarray identical to the reflectarray described in Comparative Example 3 was prepared, except for the element pattern shape. The element pattern shape was such that only the element widths of the element patterns within the reflection control region 5 differed. Specifically, the element lengths of the element patterns were set to lx1 = lx2 = lx3 = ly1 = ly2 = ly3 = 1.700 mm, and the element widths were set to wx1 = wy1, wx2 = wy2, and wx3 = wy3. HFSS was used to analyze the reflection phase of the unit cell relative to the element width w, as well as the reflection characteristics of the reflectarray 6 with and without dimensional errors.

[0234] Figure 23 This is the analysis result of the unit cell in the design process of Example 3. It shows the reflection phase when the element length of the element pattern is set to lx = ly = 1.700 mm and the element width w is changed. The reflection phase changes with the change of the element width. In addition, compared with the comparative example 3 in which the element length is changed, Figure 21 Compared to the case with the element width, the reflection phase tilts more gently with respect to the element width. For example, to change the reflection phase from 120° to -120°, the element length l in Comparative Example 3 needs to change by approximately 0.3mm, between 1.5mm and 1.8mm. In contrast, in Example 3, the element length w needs to change by approximately 1.4mm, between 0.1mm and 1.5mm. In other words, when the same degree of dimensional error occurs, Example 3, which uses element width as a design parameter, shows a smaller change in the reflection phase within the unit cell. As a result, the change in the reflection characteristics of reflectarray 6 is smaller.

[0235] The element widths are set to wx1 = wy1 = 1.362 mm, wx2 = wy2 = 0.142 mm, and wx3 = wy3 = 0.857 mm. Figure 24The analysis results of reflectarray 6 obtained in Example 3 show the reflection patterns of reflectarray 6 with and without dimensional errors in the xz plane. For reflectarray 6 without dimensional errors, electromagnetic waves incident at θix = 0° are reflected in the desired direction of θrx = 45°, with an RCS of 7.46 dBsm. Furthermore, for reflectarray 6 with dimensional errors, reflection in the direction of θrx = 0° is also produced, with an RCS of 7.46 dBsm. Therefore, the change in RCS due to dimensional error is 0.00 dBsm. Compared to the reflectarray 6 described in Comparative Example 3, which uses element length as a design parameter, the decrease in reflection intensity due to dimensional error is suppressed.

[0236] (Comparative Example 4)

[0237] Reflect array 6 has a basic structure using 0.002 mm thick copper for element pattern 1 and ground layer 3, and 0.050 mm thick PET for dielectric layer 2. The electrical conductivity of copper is set to 5.8 × 10^7 Siemens / meter, the real part of the relative permittivity of dielectric layer 2 is 3.03, and tanδ is set to 0.00476.

[0238] The operating frequency is set to 100 GHz, the target reflection characteristics are set to θix=0°, θrx=45°, and θiy=θry=0°, and the dimension Lx of the reflection control region 5 in the x-axis direction is determined to be 4.240 mm using Equation 1.

[0239] The number of divisions of the reflection control region 5 is set to 4, and the dimensions of the unit cell in the x-axis and y-axis directions are set to 1.060 mm. The shape of the element pattern is set to a cross patch with two square patches orthogonal to each other in the xy plane. Here, for each element pattern in the reflection control region 5, it is set that only the element length is different. Specifically, the element length is set to lx1 = ly1, lx2 = ly2, lx3 = ly3, lx4 = ly4, and the element width is set to wx1 = wx2 = wx3 = wy1 = wy2 = wy3 = 0.400 mm.

[0240] First, HFSS was used to analyze the reflection phase of the unit cell relative to the element length 1. Figure 25 This is a graph showing the analysis results of the unit cell during the design process of Comparative Example 4, and illustrates the reflection phase when the element width of the element pattern is set to wx=wy=0.400 mm and the element width 1 is varied. The reflection phase varies as the element length varies.

[0241] Next, based on the unit cell analysis results, the element length l in each unit cell was determined in a manner consistent with the impedance distribution of equation (7). The element length 1 was set to lx1 = ly1 = 0.929 mm, lx2 = ly2 = 0.959 mm, lx3 = ly3 = 0.862 mm, and lx4 = ly4 = 0.910 mm. The element length 1 of each element pattern was determined to have no dimensional error.

[0242] Reflectarray 6 has 12 x 12 unit cells arranged in the x- and y-directions, with a size of 12.720 mm square in the xy plane. HFSS was used to analyze the reflection characteristics of reflectarray 6 when a polarized wave parallel to the y-axis with θix = 0° and θiy = 0° was irradiated.

[0243] In order to understand the influence of dimensional errors on the reflection characteristics, a similar analysis was performed on the case where the element length 1 of each element pattern of the reflect array 6 was increased by 0.100 mm, assuming dimensional errors caused by cutting.

[0244] Figure 26 The following are the analysis results of reflectarray 6 obtained in Comparative Example 4. These graphs show the reflection characteristics of reflectarray 6 with and without dimensional errors in the xz plane. For reflectarray 6 without dimensional errors, an electromagnetic wave incident at θix = 0° is reflected in the desired direction of θrx = 45°, resulting in an RCS of -17.5 dBsm. On the other hand, for reflectarray 6 with dimensional errors, although reflection occurs in the direction of θrx = 0°, the RCS is -29.9 dBsm, indicating a change in RCS due to the dimensional errors of -12.34 dBsm.

[0245] (Example 4)

[0246] A reflectarray identical to the reflectarray described in Comparative Example 4 was prepared, except for the element pattern shape. The element pattern shape was such that only the element widths of the element patterns within the reflection control region 5 differed. Specifically, the element lengths of the element patterns were set to lx1 = lx2 = lx3 = ly1 = ly2 = ly3 = 0.900 mm, and the element widths were set to wx1 = wy1, wx2 = wy2, wx3 = wy3, and wx4 = wy4. HFSS was used to analyze the reflection phase of the unit cell relative to the element width w, as well as the reflection characteristics of the reflectarray 6 with and without dimensional errors.

[0247] Figure 27This is the analysis result of the unit cell in the design process of Example 4. It shows the reflection phase when the element length of the element pattern is set to lx = ly = 0.900 mm and the element width w is changed. The reflection phase changes with the change of the element width. In addition, compared with the comparative example 4 in which the element length is changed, Figure 25 Compared to the case with the element width, the reflection phase tilts more gently with respect to the element width. For example, to change the reflection phase from 120° to -120°, the element length l is changed by approximately 0.1mm, between 0.85mm and 0.95mm, in Comparative Example 4. In contrast, in Example 4, the element length w needs to be changed by approximately 0.45mm, between 0.2mm and 0.65mm. In other words, when the same degree of dimensional error occurs, Example 4, which uses element width as a design parameter, shows a smaller change in the reflection phase per unit cell. As a result, the change in the reflection characteristics of reflectarray 6 is smaller.

[0248] The element widths are set to wx1 = wy1 = 0.532 mm, wx2 = wy2 = 0.656 mm, wx3 = wy3 = 0.173 mm, and wx4 = wy4 = 0.456 mm. Figure 28 The following are the analysis results of reflectarray 6 obtained in Example 4, showing the reflection patterns of reflectarray 6 with and without dimensional errors on the xz plane. For the reflectarray 6 without dimensional errors, electromagnetic waves incident at θix = 0° are reflected in the desired direction of θrx = 45°, with an RCS of -17.4 dBsm. Furthermore, for the reflectarray with dimensional errors, reflection in the direction of θrx = 0° is also produced, with an RCS of -19.9 dBsm. Therefore, the change in RCS due to dimensional error is -2.51 dBsm, which suppresses the decrease in reflection intensity due to dimensional error compared to the reflectarray described in Comparative Example 4, which uses element length as a design parameter.

[0249] (Example 5)

[0250] The basic structure is to use copper with a thickness of 0.018 mm for the element pattern 1 and the ground layer 3 and a glass / fluororesin composite material with a thickness of 0.764 mm for the dielectric layer 2. Figure 2 A 0.098 mm thick exterior layer 10 is laminated in the manner (c) to form a reflective array 6c. The electrical conductivity of copper is set to 5.8×10^7 Siemens / meter, the real part of the relative permittivity of dielectric layer 2 is 2.6, and the tanδ is set to 0.0025. The real part of the relative permittivity of exterior layer 10 is 2.70, and the tanδ is set to 0.0060.

[0251] The operating frequency is set to 27.2 GHz, the target reflection characteristics are set to θix=33°, θrx=0°, and θiy=θry=0°, and the dimension Lx of the reflection control area 5 in the x-axis direction is determined to be 20.238 mm using Equation 1.

[0252] The number of divisions of the reflection control area 5 is set to 3, and the dimensions of the unit cell in the x-axis and y-axis directions are set to 6.746mm. The shape of the element pattern is set to a cross patch with two square patches orthogonal to each other in the xy plane. Here, for each element pattern in the reflection control area 5, it is set that only the element width is different. Specifically, the element length is set to lx1=lx2=lx3=ly1=ly2=ly3=3.250mm, and the element width is set to wx1=wy1=1.582mm, wx2=wy2=2.955mm, and wx3=wy3=0.319mm.

[0253] The reflect array 6c has 9 x 9 unit cells arranged in the x- and y-directions, with a size of 60.714 mm square in the xy plane. HFSS was used to analyze the reflection characteristics of the reflect array 6c when a polarized wave parallel to the y-axis with θix = 33° and θiy = 0° was irradiated.

[0254] Figure 29 This is a graph showing the reflection characteristics of the reflect array 6c on the xz plane, and the analysis results obtained in Example 5. An electromagnetic wave incident at θix = 33° is reflected in the desired direction of θrx = 0°, and its RCS is 0.23 dBsm.

[0255] (Example 6)

[0256] The basic structure is to use copper with a thickness of 0.018 mm for the element pattern 1 and the ground layer 3 and a glass / fluororesin composite material with a thickness of 0.764 mm for the dielectric layer 2. Figure 2 A polyimide protective layer 8 with a thickness of 0.060 mm was laminated in the manner (a) to form a reflect array 6a. The electrical conductivity of copper was set to 5.8 × 10^7 Siemens / meter, the real part of the relative permittivity of the dielectric layer was set to 2.6, and the tanδ was set to 0.0025. The real part of the relative permittivity of the protective layer 8 was set to 3.23, and the tanδ was set to 0.0144.

[0257] The operating frequency is set to 27.2 GHz, the target reflection characteristics are set to θix=33°, θrx=0°, and θiy=θry=0°, and the dimension Lx of the reflection control area 5 in the x-axis direction is determined to be 20.238 mm using Equation 1.

[0258] The number of divisions of the reflection control area 5 is set to 3, and the dimensions of the unit cell in the x-axis and y-axis directions are set to 6.746mm. The shape of the element pattern is set to a cross patch with two square patches orthogonal to each other in the xy plane. Here, for each element pattern in the reflection control area 5, it is set that only the element width is different. Specifically, the element length is set to lx1=lx2=lx3=ly1=ly2=ly3=3.000mm, and the element width is set to wx1=wy1=1.703mm, wx2=wy2=2.986mm, and wx3=wy3=0.075mm.

[0259] The reflect array 6a has 9 x 9 unit cells arranged in the x- and y-directions, with a size of 60.714 mm square in the xy plane. HFSS was used to analyze the reflection characteristics of the reflect array when a polarized wave parallel to the y-axis with θix = 33° and θiy = 0° was irradiated.

[0260] Figure 30 This is a graph showing the reflection characteristics of the reflect array 6a on the xz plane, and the analysis results of the reflect array 6a obtained in Example 6. An electromagnetic wave incident at θix = 33° is reflected in the desired direction of θrx = 0°, and its RCS is 0.17 dBsm.

[0261] (Example 7)

[0262] Reflect array 6 has a basic structure using 0.002mm thick copper for the element pattern and ground layer, and 0.050mm thick polystyrene for the dielectric layer. The electrical conductivity of copper is 5.8×10^7 Siemens / meter, the real part of the relative permittivity of the dielectric layer is 2.47, and tanδ is 0.000644.

[0263] The operating frequency is set to 28 GHz, the target reflection characteristics are set to θix=0°, θrx=45°, θiy=θry=0°, and the x-axis dimension Lx of the reflection control area 5 is determined to be 15.140 mm using equation (1).

[0264] The number of divisions of the reflection control area 5 is set to 4, and the dimensions of the unit cell in the x-axis and y-axis directions are set to 3.785mm. The shape of the element pattern is set to a cross patch with two square patches orthogonal to each other in the xy plane. Here, for each element pattern in the reflection control area 5, it is set that only the element width is different. Specifically, the element length is set to lx1=lx2=lx3=ly1=ly2=ly3=3.450mm, and the element width is set to wx1=wy1=2.697mm, wx2=wy2=2.892mm, wx3=wy3=2.460mm, and wx4=wy4=2.639mm.

[0265] Reflectarray 6 has 16 x 16 unit cells arranged in the x- and y-directions, resulting in a 60.560 mm square dimension in the xy plane. HFSS was used to analyze the reflection characteristics of reflectarray 6 when a polarized wave parallel to the y-axis with θix = 0° and θiy = 0° was incident on the reflectarray.

[0266] Figure 31 This is the analysis result of the reflect array 6 obtained in Example 7, and is a diagram showing the reflection characteristics of the reflect array 6 on the xz plane. An electromagnetic wave incident at θix = 0° is reflected in the desired direction of θrx = 45°, and its RCS is -5.91 dBsm.

[0267] (Action / Effect)

[0268] By using the element width as a design parameter, phase changes due to the design parameters can be reduced, and degradation of the reflection characteristics due to dimensional errors can be suppressed. As a result, the yield rate of the reflect array can be improved.

[0269] While the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

[0270] [Other embodiments]

[0271] The following description is of possible embodiments of the present invention, but the present invention is not limited thereto.

[0272] (Method 1)

[0273] A reflective array is obtained by stacking at least an element pattern, a dielectric layer, and a ground layer in sequence, characterized in that:

[0274] The reflective array comprises at least one reflection control region,

[0275] The reflection control region has at least 2 unit cells,

[0276] One of the element patterns is arranged in the unit cell.

[0277] The component pattern includes two cross patches orthogonal to each other in the xy plane.

[0278] In the reflection control region, the first element width wx (width in the x-axis direction) and / or the second element width wy (width in the y-axis direction) of the element pattern are different for each element pattern respectively arranged in the at least two unit cells.

[0279] (Method 2)

[0280] The reflect array according to embodiment 1 is characterized in that, in the element pattern, the two square patches of the cross patch share a common center of gravity and are orthogonal to each other, and the shape of the element pattern on the xy plane is line symmetric with respect to the x-axis and the y-axis.

[0281] (Method 3)

[0282] The reflect array according to aspect 1 or 2 is characterized in that, in the xy plane, the center of gravity of the element pattern and the center of gravity of the unit cell are the same.

[0283] (Method 4)

[0284] The reflect array according to any one of aspects 1 to 3, wherein gaps gx between the element patterns in the x-axis direction are equal.

[0285] (Method 5)

[0286] The reflect array according to any one of aspects 1 to 4, wherein gaps gy between the element patterns in the y-axis direction are equal.

[0287] (Method 6)

[0288] The reflect array according to any one of aspects 1 to 5 is characterized in that the gaps gx between the element patterns in the x-axis direction are equal, and the gaps gy between the element patterns in the y-axis direction are equal, and gy and gy are equal.

[0289] (Method 7)

[0290] The reflect array according to any one of aspects 1 to 6 is characterized in that the gaps gx between the element patterns in the x-axis direction are equal, and the gaps gy between the element patterns in the y-axis direction are equal, and gy and gy are different.

[0291] (Method 8)

[0292] The reflect array according to any one of aspects 1 to 7, wherein the element pattern is composed of cross patches.

[0293] (Method 9)

[0294] The reflect array according to any one of aspects 1 to 8, wherein the element pattern is composed of the cross patch and a ring surrounding the cross patch on the xy plane.

[0295] (Method 10)

[0296] The reflect array according to any one of means 1 to 9, wherein the element pattern is formed of a Jerusalem cross shape on the xy plane.

[0297] (Method 11)

[0298] The reflective array according to any one of aspects 1 to 10, comprising an exterior layer.

[0299] (Method 12)

[0300] The reflect array according to any one of means 1 to 11, further comprising a protective layer.

[0301] (Method 13)

[0302] A reflective array device, wherein the reflective array according to any one of modes 1 to 12 is provided on a support body.

[0303] (Method 14)

[0304] A method for designing a reflect array is a method for designing a reflect array obtained by stacking at least an element pattern, a dielectric layer, and a ground layer in sequence, characterized in that:

[0305] The reflective array comprises at least one reflection control region,

[0306] The reflection control region has at least 2 unit cells,

[0307] One of the element patterns is arranged in the unit cell,

[0308] The element pattern includes two cross patches orthogonal to each other in the xy plane.

[0309] The width of the element pattern in the x-axis direction, i.e., the first element width wx, and / or the width in the y-axis direction, i.e., the second element width wy, are set based on the reflection phase in the simulation of the reflection characteristics of the element pattern, and the reflection phase is derived from the first element width wx and the second element width wy as design parameters.

[0310] Description of the label

[0311] 1.11-1 n , 1d1-1d3, 1e1-1e3, 1a-1c, 1 x 1-1 x n 、1 y 1-1 y n : Component pattern, 2: Dielectric layer, 3: Ground layer, 4, 41-4 n , 4a―4c, 4 x 1-4 x n , 4 y 1-4 yn : Unit cell, 5, 5a-5h, 5x, 5y: Reflection control area, 6, 6a-6h: Reflection array, 7: Functional layer, 8: Protective layer, 9: Adhesive layer, 10: Appearance layer, 11: Setting layer.

Claims

1. A reflective array, which is obtained by stacking at least an element pattern, a dielectric layer, and a ground layer in order, characterized in that: The reflective array comprises at least one reflection control region, The reflection control region has at least 2 unit cells, One of the element patterns is arranged in the unit cell. The element pattern includes a cross patch that makes two square patches orthogonal to each other on the xy plane, In the reflection control region, the first element width wx, which is the width of the element pattern in the x-axis direction, and / or the second element width wy, which is the width in the y-axis direction, are different for each element pattern respectively arranged in the at least two unit cells.

2. The reflective array according to claim 1, wherein: In the element pattern, the two square patches of the cross patch share a common center of gravity and are orthogonal to each other, and the shape of the element pattern on the xy plane is line-symmetrical with respect to the x-axis and the y-axis.

3. The reflective array according to claim 1, wherein: In the xy plane, the center of gravity of the element pattern and the center of gravity of the unit cell are the same.

4. The reflective array according to claim 1, wherein: The gaps gx between the element patterns in the x-axis direction are equal.

5. The reflective array according to claim 1, wherein: The gaps gy between the element patterns in the y-axis direction are equal.

6. The reflective array according to claim 1, wherein: The gaps gx between the element patterns in the x-axis direction are equal, and the gaps gy between the element patterns in the y-axis direction are equal, and gy and gy are equal.

7. The reflective array according to claim 1, wherein: The gaps gx between the element patterns in the x-axis direction are equal, and the gaps gy between the element patterns in the y-axis direction are equal, and gy and gy are different.

8. The reflective array according to claim 1, wherein: The element pattern is composed of cross patches.

9. The reflective array according to claim 1, wherein: The element pattern on the xy plane is composed of the cross patch and a ring surrounding the cross patch.

10. The reflective array according to claim 1, wherein: The element pattern is composed of a Jerusalem cross shape on the xy plane.

11. The reflective array according to claim 1, wherein: Has an appearance layer.

12. The reflective array according to claim 1, wherein: With protective layer.

13. A reflect array device, comprising the reflect array according to claim 1 provided on a support body.

14. A method for designing a reflect array, wherein at least an element pattern, a dielectric layer, and a ground layer are sequentially stacked, characterized in that: The reflective array comprises at least one reflection control region, The reflection control region has at least 2 unit cells, One of the element patterns is arranged in the unit cell, The element pattern includes two cross patches orthogonal to each other in the xy plane. The width of the element pattern in the x-axis direction, i.e., the first element width wx, and / or the width in the y-axis direction, i.e., the second element width wy, are set based on the reflection phase in the simulation of the reflection characteristics of the element pattern, and the reflection phase is derived from the first element width wx and the second element width wy as design parameters.

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