Frequency-selective reflector

Abstract

The present disclosure provides a frequency-selective reflector that reflects electromagnetic waves of a specific frequency band which is greater than or equal to 24 GHz, in a direction differing from the regular reflection direction, said frequency-selective reflector having: a reflection member that reflects the electromagnetic waves; and a dielectric layer that is positioned on the electromagnetic wave incidence side of the reflection member, and transmits the electromagnetic waves, wherein the dielectric layer has two or more types of thickness, and has a plurality of first regions in which the thickness is thin and a plurality of second regions in which the thickness is thick.

Description

Frequency Selective Reflector

[0001] The present disclosure relates to a frequency selective reflector that reflects electromagnetic waves in a specific frequency band in a direction different from the specular reflection direction.

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

[0003] A reflectarray is required to reflect electromagnetic waves of a specific frequency incident from a base station in a predetermined direction in a desired direction. Such a reflectarray, for example, has an array of multiple reflecting elements. Technology has been developed to change the dimensions and shape of the reflecting elements to change the resonant frequency of each reflecting element and control the reflection phase of the electromagnetic waves, thereby controlling the incident and reflection directions of the electromagnetic waves.

[0004] Patent No. 5371633 Patent No. 5162677

[0005] Hiroki Matsuno et al., "Development of a visible light-transmitting metasurface reflector," IEICE Technical Report, 2020, Vol. 120, No. 9, pp. 13-17; Mayumi Yoshino et al., "Improvement of received power in non-line-of-sight environments in L-shaped corridors using a metasurface reflector," IEICE Technical Report, A.P.2020-5 (2020-04)

[0006] It is known that in a reflectarray, the pattern of the reflective elements is formed by etching a metal layer using, for example, photolithography technology.

[0007] In a mobile communication system, the relationship between the location of the base station, the location of the coverage hole, and the installation location of the reflectarray can vary depending on the situation. Therefore, it is necessary to use a reflectarray with reflection characteristics that achieve the desired angle of incidence and reflection angle depending on the situation.

[0008] However, with the above-mentioned reflect array, if one tries to customize the reflection characteristics to suit various situations, it is necessary to customize the photomask used in the photolithography processing of the metal layer, which increases manufacturing costs and lengthens manufacturing time.

[0009] Furthermore, in the reflectarray, for example, the reflection angle can be increased by narrowing the pitch of the reflecting elements. However, in a planar array of reflecting elements, there is a limit to how narrow the pitch of the reflecting elements can be, making it difficult to increase the reflection angle. Furthermore, since there is a limit to the processing accuracy in photolithography processing of the metal layer, it is difficult to precisely control the reflection phase at high frequencies where the wavelength is short and processing accuracy is required.

[0010] The present disclosure has been made in view of the above circumstances, and has as its main object to provide a frequency selective reflector that can reduce manufacturing costs and shorten manufacturing time.

[0011] One embodiment of the present disclosure provides a frequency selective reflector that reflects electromagnetic waves in a specific frequency band of 24 GHz or higher in a direction different from a specular reflection direction, the frequency selective reflector comprising: a reflecting member that reflects the electromagnetic waves; and a dielectric layer that is arranged on the incident side of the electromagnetic waves relative to the reflecting member and transmits the electromagnetic waves, the dielectric layer having two thicknesses and including a plurality of first regions that are thinner and a plurality of second regions that are thicker.

[0012] Another embodiment of the present disclosure provides a frequency selective reflector that reflects electromagnetic waves in a specific frequency band in a direction different from a specular reflection direction, the frequency selective reflector comprising: a substrate; a reflecting member that is disposed on one surface of the substrate and reflects the electromagnetic waves; and a dielectric member that is disposed on a surface of the reflecting member opposite the substrate and transmits the electromagnetic waves, the dielectric member having, from the reflecting member side, a first dielectric layer and a second dielectric layer, in this order, the first dielectric layer having a plurality of first dielectric portions disposed on the surface of the reflecting member opposite the substrate, the second dielectric layer having a plurality of second dielectric portions disposed on the surface of the first dielectric layer opposite the reflecting member, the second dielectric portions being arranged so as to overlap boundaries between adjacent first dielectric portions in a planar view, the first dielectric portions having a first dielectric pattern, and the second dielectric portion having a second dielectric pattern.

[0013] The frequency selective reflector of the present disclosure has the effect of enabling reduction in manufacturing costs and shortening of manufacturing time.

[0014] 1A and 1B are schematic plan views and cross-sectional views illustrating a frequency selective reflector of the present disclosure, and a schematic diagram for explaining the relative reflection phase of an electromagnetic wave at a first region and a second region of a dielectric layer in the frequency selective reflector of the present disclosure. FIG. 1C is a schematic diagram illustrating the reflection characteristics of the frequency selective reflector of the present disclosure. FIG. 1D is a schematic plan view illustrating a reflecting member in the frequency selective reflector of the present disclosure. FIG. 1E is a schematic plan view illustrating a frequency selective reflector of the present disclosure, and a schematic diagram for explaining the relative reflection phase of an electromagnetic wave at a first region and a second region of a dielectric layer in the frequency selective reflector of the present disclosure. FIG. 1F is a schematic diagram illustrating the reflection characteristics of the frequency selective reflector of the present disclosure. FIG. 1G is a schematic plan view illustrating a frequency selective reflector of the present disclosure. FIG. 1H is a schematic diagram illustrating the incident direction and reflection direction of an electromagnetic wave with respect to a frequency selective reflector. FIG. 1H is a schematic plan view and cross-sectional views illustrating a frequency selective reflector of the present disclosure. FIG. 1I is a schematic plan view and cross-sectional views illustrating a dielectric layer in the frequency selective reflector of the present disclosure. FIG. 1 shows a schematic plan view and a cross-sectional view illustrating a dielectric layer in a frequency selective reflector of the present disclosure. FIG. 2 shows a schematic cross-sectional view illustrating a frequency selective reflector of the present disclosure, and a schematic diagram for explaining the relative reflection phase of electromagnetic waves in a first region and a second region of a dielectric layer in a frequency selective reflector of the present disclosure. FIG. 3 shows a schematic cross-sectional view illustrating a frequency selective reflector of the present disclosure. FIG. 4 shows a schematic plan view illustrating a reflecting member in a frequency selective reflector of the present disclosure, and a schematic cross-sectional view illustrating a frequency selective reflector of the present disclosure. FIG. 5 shows a schematic cross-sectional view illustrating a frequency selective reflector of the present disclosure. FIG. 6 shows a schematic cross-sectional view and a plan view illustrating a frequency selective reflector of the present disclosure. FIG. 7 shows a schematic plan view and a cross-sectional view illustrating a first dielectric portion constituting a first dielectric layer in the present disclosure. FIG. 8 shows a schematic plan view and a cross-sectional view illustrating a second dielectric portion constituting a second dielectric layer in the present disclosure. 1 is a schematic cross-sectional view illustrating a frequency selective reflector of the present disclosure, and a schematic diagram illustrating the relative reflection phases of electromagnetic waves in the A1 region, the A2 region, and the A3 region of a dielectric member in the frequency selective reflector of the present disclosure.FIG. 1 is a schematic plan view illustrating a frequency selective reflector of the present disclosure. FIG. 2 is a schematic plan view illustrating a frequency selective reflector of the present disclosure. FIG. 3 is a schematic cross-sectional view illustrating a first dielectric portion constituting a first dielectric layer in a frequency selective reflector of the present disclosure. FIG. 4 is a schematic plan view illustrating a frequency selective reflector of the present disclosure, and a schematic plan view illustrating the first dielectric layer and the second dielectric layer in a frequency selective reflector of the present disclosure. FIG. 5 is a schematic plan view illustrating a frequency selective reflector of the present disclosure, and a schematic plan view illustrating the first dielectric layer and the second dielectric layer in a frequency selective reflector of the present disclosure. FIG. 6 is a schematic plan view illustrating a frequency selective reflector of the present disclosure, and a schematic plan view illustrating the first dielectric layer and the second dielectric layer in a frequency selective reflector of the present disclosure. FIG. 7 is a schematic plan view illustrating a frequency selective reflector of the present disclosure, and a schematic plan view illustrating the first dielectric layer and the second dielectric layer in a frequency selective reflector of the present disclosure. FIG. 1 is a schematic cross-sectional view illustrating a frequency selective reflector of the present disclosure. FIG. 2 is a schematic cross-sectional view illustrating a frequency selective reflector of the present disclosure. FIG. 3 is a schematic cross-sectional view illustrating a frequency selective reflector of the present disclosure, and a schematic diagram illustrating the relative reflection phases of electromagnetic waves in the A1 region, the A2 region, and the A3 region of the dielectric member in the frequency selective reflector of the present disclosure. FIG. 4 is a schematic cross-sectional view illustrating a frequency selective reflector of the present disclosure. FIG. 5 is a schematic plan view illustrating a dielectric member in the frequency selective reflector of the present disclosure. FIG. 6 is a schematic plan view illustrating a dielectric member in the frequency selective reflector of the present disclosure, and a schematic diagram illustrating the relative reflection phases of electromagnetic waves in each region of the dielectric member in the frequency selective reflector of the present disclosure. FIG. 7 is a schematic plan view and a cross-sectional view illustrating a first dielectric portion constituting the first dielectric layer in the present disclosure. FIG. 8 is a schematic plan view illustrating a frequency selective reflector of the present disclosure. FIG. 9 is a schematic plan view illustrating a frequency selective reflector of the present disclosure. 1 is a schematic cross-sectional view illustrating a frequency selective reflector according to the present disclosure.FIG. 1 is a schematic plan view illustrating a reflecting member in a frequency selective reflector of the present disclosure, and a schematic cross-sectional view illustrating the frequency selective reflector of the present disclosure. FIG. 2 is a schematic plan view illustrating a reflecting member in a frequency selective reflector of the present disclosure, and a schematic cross-sectional view illustrating the frequency selective reflector of the present disclosure. FIG. 3 is a schematic cross-sectional view illustrating the frequency selective reflector of the present disclosure. FIG. 4 is a received power distribution diagram showing a simulation result of Example 1. FIG. 5 is a received power distribution diagram showing a simulation result of Example 2. FIG. 6 is a received power distribution diagram showing a simulation result of Reference Example 1. FIG. 7 is a received power distribution diagram showing a simulation result of Example 3. FIG. 8 is a diagram showing a simulation result of Reference Example 2. FIG. 9 is a schematic diagram illustrating a transmission line equivalent circuit.

[0015] Embodiments of the present disclosure will be described below with reference to the drawings and the like. However, the present disclosure can be implemented in many different forms and should not be construed as being limited to the description of the embodiments exemplified below. Furthermore, to clarify the explanation, the drawings may show the width, thickness, shape, etc. of each part schematically compared to the actual form, but these are merely examples and do not limit the interpretation of the present disclosure. Furthermore, in this specification and each drawing, elements similar to those described above with reference to the previous drawings may be designated by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0016] In this specification, when describing a mode in which another component is placed on a certain component, the term "above" or "below" includes, unless otherwise specified, both a case in which another component is placed directly above or below a certain component so as to be in contact with the component, and a case in which another component is placed above or below a certain component with another component interposed therebetween. Also, in this specification, when describing a mode in which another component is placed on the surface of a certain component, the term "on the surface" includes, unless otherwise specified, both a case in which another component is placed directly above or below a certain component so as to be in contact with the component, and a case in which another component is placed above or below a certain component with another component interposed therebetween.

[0017] The frequency selective reflector of the present disclosure will be described in detail below.

[0018] A. Frequency Selective Reflector The frequency selective reflector in the present disclosure has two embodiments, each of which will be described below.

[0019] I. First Embodiment The main object of this embodiment is to provide a frequency selective reflector that can control the reflection direction of electromagnetic waves with a simple structure, and that can reduce manufacturing costs and shorten manufacturing time.

[0020] The frequency selective reflector of this embodiment is a frequency selective reflector that reflects electromagnetic waves in a specific frequency band of 24 GHz or higher in a direction other than the direct reflection direction, and has a reflecting member that reflects the electromagnetic waves, and a dielectric layer that is arranged on the incident side of the electromagnetic waves relative to the reflecting member and transmits the electromagnetic waves, and the dielectric layer has two types of thickness and has a plurality of first regions with a thin thickness and a plurality of second regions with a thick thickness.

[0021] 1(a) and 1(b) are schematic plan and cross-sectional views showing an example of a frequency selective reflector according to this embodiment, and FIG. 1(b) is a cross-sectional view taken along line A-A in FIG. 1(a). As shown in FIGS. 1(a) and 1(b), the frequency selective reflector 1 includes a reflecting member 2 that reflects specific electromagnetic waves and a dielectric layer 305 that is disposed on the electromagnetic wave incident side of the reflecting member 2 and transmits the specific electromagnetic waves. The frequency selective reflector 1 may also include an adhesive layer 306 between the reflecting member 2 and the dielectric layer 305. The dielectric layer 305 has two thicknesses, t31 and t32, and includes a plurality of first regions 311 having a smaller thickness t31 and a plurality of second regions 312 having a larger thickness t32. While the thickness t31 of the first region 311 of the dielectric layer 305 is 0 in FIG. 1(b), the thickness of the first region is not limited to this.

[0022] In the dielectric layer 305, the thickness t31 of the first region 311 is different from the thickness t32 of the second region 312, and therefore the round-trip optical path length when the electromagnetic wave passes through the dielectric layer 305, is reflected by the reflecting member 2, passes through the dielectric layer 305 again, and is emitted to the electromagnetic wave incident side is different between the first region 311 and the second region 312. The difference in the round-trip optical path length in these dielectric layers, that is, the optical path difference, creates a difference in the relative reflection phase.

[0023] The reason why the term "optical path length" is used in this specification is that the wavelengths of the frequency bands targeted in this disclosure are closer to those of light and have a higher degree of directivity compared to conventional pre-LTE frequency bands, and therefore it is easier to explain the behavior of the frequency bands as being similar to that of light. The optical path length actually means the effective distance that an electromagnetic wave travels through a dielectric layer.

[0024] 1(c) is a graph in which the horizontal axis represents the position in a predetermined direction D1 of the dielectric layer 305 and the vertical axis represents the relative reflection phase when the electromagnetic wave passes through the dielectric layer 305, is reflected by the reflecting member 2, passes through the dielectric layer 305 again, and is emitted toward the electromagnetic wave incident side, and the value of the relative reflection phase of the electromagnetic wave is between −360 degrees and 0 degrees, and is an example of the relative reflection phase of the electromagnetic wave in the first region and the second region of the dielectric layer in the frequency selective reflector shown in FIGS. 1(a) and 1(b). As shown in FIG. 1(c), the relative reflection phase of the electromagnetic wave in the first region 311 and the second region 312 of the dielectric layer 305 is 0 degrees (−360 degrees) and −180 degrees, respectively.

[0025] In this specification, the term "reflection phase" refers to the amount of change in the phase of a reflected wave relative to the phase of an incident wave that is incident on a surface. In the case of a frequency selective reflector having a reflecting member and a dielectric layer in this embodiment, however, the term "reflection phase" refers to the amount of change in the phase of a reflected wave relative to the phase of the incident wave when the incident wave passes through the dielectric layer, is reflected by the reflecting member, passes through the dielectric layer again, and is emitted.

[0026] In addition, in this specification, the "relative reflection phase" refers to the reflection phase in one of the first and second regions of the dielectric layer, which has a smaller reflection phase delay, and is expressed as a negative value representing the delay of the reflection phase in the other region relative to the reference reflection phase. For example, if the reflection phase in one of the first and second regions of the dielectric layer, which has a smaller reflection phase delay, is -10 degrees, the relative reflection phase in a region where the reflection phase is -40 degrees will be -30 degrees.

[0027] As will be described later, if the reflecting member has a reflection phase control function, the relative reflection phase of the electromagnetic wave in the first and second regions of the dielectric layer is a value that also includes the reflection phase in the reflecting member.

[0028] Unless otherwise specified, the reflection phase is in the range of more than -360 degrees and less than 360 degrees, and -360 degrees and +360 degrees return to 0 degree. Furthermore, unless otherwise specified, the relative reflection phase is in the range of more than -360 degrees and 0 degree or less, and -360 degrees returns to 0 degree.

[0029] In a conventional reflectarray in which multiple reflecting elements are arranged, the reflection phase can be delayed or advanced by adjusting the dimensions and shape of the reflecting elements, for example. In contrast, in the frequency selective reflector of this embodiment, the reflection phase is basically delayed by adjusting the thicknesses of the first and second regions of the dielectric layer. Therefore, the relative reflection phase is determined based on the reflection phase in the region of the first and second regions of the dielectric layer that has the least reflection phase delay.

[0030] Furthermore, of the first and second regions of the dielectric layer, the region with the smallest reflection phase delay is usually the first region, which has a smaller thickness.

[0031] As described above, by changing the thicknesses t31 and t32 of the dielectric layer 305, the round-trip optical path length in the dielectric layer 305 changes, and the relative reflection phase of the electromagnetic wave changes. In conventional reflectarrays, the reflection direction of the electromagnetic wave is controlled by utilizing the property that the electromagnetic wave travels in the normal direction of an in-phase plane. The frequency selective reflector of this embodiment can also control the reflection direction of the electromagnetic wave in a similar manner. For example, in a frequency selective reflector having the reflection characteristics shown in FIG. 1( c), when a plane wave is incident from directly above the frequency selective reflector, the line (plane) connecting the centers of the first region 311 and the second region 312 in order can be considered as the in-phase plane of the reflected wave, and the reflected wave travels in the normal direction.

[0032] The frequency-selective reflector of this embodiment is a so-called 1-bit reflectarray, which has a 1-bit reflection phase change. Therefore, in the first region 311, the relative reflection phase of the electromagnetic wave is equivalent to 0 degrees and -360 degrees. Therefore, the line (plane) connecting the centers of the first region 311 and the second region 312 in order forms two identical phase planes, sloping downward to the right and downward to the left. As a result, when a plane wave is incident from directly above the frequency-selective reflector, the reflected wave is generated axially symmetrically, and although the reflected power in each direction is halved, it is possible to deliver the electromagnetic wave in the set reflection direction. Furthermore, when the incident wave is incident from a direction oblique to the frequency-selective reflector rather than from the front direction, the reflected wave is axially symmetric, but the reflected power in one direction is strongly reflected, allowing for more effective delivery of the electromagnetic wave. Note that the reduction in reflected power due to this symmetry can be compensated for by methods such as increasing the area of ​​the frequency-selective reflector.

[0033] 2, the incident electromagnetic wave W1 can be reflected in a direction different from the regular reflection (specular reflection) direction. In this case, the incident angle θ1 of the incident electromagnetic wave W1 is different from the reflection angle θ2 of the reflected electromagnetic wave W2.

[0034] Therefore, in the frequency selective reflector of this embodiment, by changing the thickness of the first region and the second region of the dielectric layer, the round-trip optical path length in the dielectric layer can be changed between the first region and the second region, and the reflection phase of the electromagnetic wave can be controlled, thereby controlling the reflection direction of the electromagnetic wave relative to a predetermined incident direction to any direction.

[0035] Furthermore, the dielectric layer in this embodiment can be formed by various techniques, such as cutting, laser processing, molding using a mold, 3D printing, or joining small pieces. Therefore, unlike the photolithography processing of metal layers in conventional reflectarrays, a photomask is not required. Furthermore, the dielectric layer has only two thicknesses. Therefore, the desired dielectric layer can be formed relatively inexpensively and in a short period of time. In particular, when the dielectric layer is formed by cutting or laser processing, manufacturing costs and manufacturing time can be significantly reduced. Therefore, it is easy to meet the needs for small-lot, high-mix production. Furthermore, it is possible to use highly durable materials such as engineering plastics, which are not well suited for molding or 3D printing. Furthermore, since the dielectric layer has only two thicknesses, the maximum thickness of the dielectric layer can be reduced. Therefore, in the frequency selective reflector of this embodiment, the reflection phase of the electromagnetic wave can be controlled by the thickness of the dielectric layer, thereby controlling the reflection direction of the electromagnetic wave, thereby achieving a thin frequency selective reflector.

[0036] In addition, in the frequency selective reflector of this embodiment, the thickness of the first and second regions of the dielectric layer and the pitch of the first or second region of the dielectric layer affect the control of the reflection characteristics. The thickness of the first and second regions of the dielectric layer and the pitch of the first or second region of the dielectric layer have a relatively wide processable range, so it is possible to increase, for example, the angle of incidence or reflection of the electromagnetic wave, thereby widening the control range of the reflection characteristics. Furthermore, the thickness of the first and second regions of the dielectric layer and the pitch of the first or second region of the dielectric layer have a relatively wide margin of dimensional processing accuracy for achieving a desired reflection phase, so it is easy to obtain the desired reflection characteristics and the effects of dimensional variations can be reduced.

[0037] In the frequency selective reflector of this embodiment, the reflecting member may be a frequency selective plate that reflects only specific electromagnetic waves. Fig. 3 is a schematic plan view illustrating an example of a reflecting member, and is an example of the reflecting member shown in Fig. 1(b). As shown in Fig. 3, the reflecting member 2 has a plurality of ring-shaped reflecting elements 3 arranged on a dielectric substrate 4 and a plurality of reflecting elements 3 arranged on the surface of the dielectric substrate 4 facing the dielectric layer 305.

[0038] Furthermore, in the frequency selective reflector of this embodiment, the reflecting member may be a frequency selective plate that reflects only specific electromagnetic waves and has a reflection phase control function that controls the reflection phase of the electromagnetic waves. In such a reflecting member, by changing the dimensions and shape of the reflecting elements, the resonant frequency of each reflecting element can be changed and the reflection phase of the target electromagnetic wave can be controlled. In this case, the reflection phase of the electromagnetic wave can be controlled not only by the thickness of the dielectric layer but also by the dimensions and shape of the reflecting elements, thereby improving the design freedom in controlling the reflection characteristics.

[0039] Therefore, in the frequency selective reflector of this embodiment, when the above-mentioned reflective member is used, the degree of freedom in controlling the reflection characteristics can be increased by combining it with the above-mentioned dielectric layer. For example, one example is to prepare multiple types of reflective members for the reflection characteristics in the vertical direction and combine them with a dielectric layer that adjusts the reflection characteristics in the horizontal direction.

[0040] Furthermore, the inventors of the present disclosure conducted a simulation of the reflection characteristics of electromagnetic waves in a specific frequency band in a frequency selective reflector having a reflecting member and a dielectric layer according to the present embodiment, in which the reflecting member is a frequency selective reflector having a reflecting element that reflects only specific electromagnetic waves. As a result, it was found that the reflection phase shift caused by changing the thickness of the first and second regions of the dielectric layer to change the round-trip optical path length in the dielectric layer between the first and second regions is greater than the reflection phase shift caused by the proximity of the dielectric layer to the reflecting member (frequency selective reflector). They also found that the design of the actual reflection characteristics can be largely determined by the design of the dielectric layer. In this case, the resonant frequency of the reflecting element varies depending on whether or not there is a nearby dielectric layer, but practical problems can be solved by designing it assuming the presence of a dielectric layer. Furthermore, it was found that the in-plane arrangement of the first and second regions of the dielectric layer that realizes the in-plane distribution design of the reflection phase in the frequency selective reflector does not need to have a fixed positional relationship with the in-plane arrangement of the reflecting elements of the reflecting member, and that even if the first and second regions of the dielectric layer are arranged offset from the in-plane arrangement of the reflecting elements, this does not have a significant impact on the reflection characteristics.

[0041] Therefore, when combining the above-mentioned dielectric layer with the above-mentioned reflecting member in the frequency selective reflector of this embodiment, the dielectric layer and the reflecting member can be designed independently and combined. In this case, a dielectric layer that achieves reflection characteristics according to the usage environment can be manufactured each time, or multiple specifications can be prepared in advance. This makes it easier to design the reflection direction of the frequency selective reflector that changes depending on the usage environment. As described above, when the overall reflection characteristics of the frequency selective reflector are adjusted by combining the reflection phase distributions of the reflecting member and the dielectric layer, precision in the misalignment of the reflecting member and the dielectric layer is required according to the required specifications. However, when the reflection characteristics of the frequency selective reflector are adjusted only by the reflection phase distribution of the dielectric layer, precision in the misalignment of the reflecting member and the dielectric layer is not required.

[0042] Each configuration of the frequency selective reflector of this embodiment will be described below.

[0043] 1. Dielectric Layer The dielectric layer in this embodiment is a member that is disposed on the electromagnetic wave incident side of the reflecting member and transmits electromagnetic waves in a specific frequency band. The dielectric layer has two thicknesses, namely, a plurality of first regions having a smaller thickness and a plurality of second regions having a larger thickness.

[0044] (1) Structure of the Dielectric Layer The dielectric layer has two thicknesses, namely, a plurality of first regions having a small thickness and a plurality of second regions having a large thickness.

[0045] In the dielectric layer, the absolute value of the difference between the relative reflection phase of the electromagnetic wave in the first region and the relative reflection phase of the electromagnetic wave in the second region can be greater than 0 degrees and less than 360 degrees. As described below, in the present disclosure, two dielectric layers may be disposed overlapping each other in the thickness direction. When only one dielectric layer is used, the absolute value of the difference in the relative reflection phase of the electromagnetic wave is, for example, preferably 150 degrees or more and 210 degrees or less, more preferably 170 degrees or more and 190 degrees or less, and even more preferably 175 degrees or more and 185 degrees or less. In this case, the closer the absolute value of the difference in the relative reflection phase of the electromagnetic wave is to 180 degrees, the more the wavefront distortion of the reflected wave can be suppressed. Furthermore, when two dielectric layers are disposed overlapping each other in the thickness direction, the absolute value of the difference in the relative reflection phase of the electromagnetic wave is, for example, preferably 90 degrees or more and 150 degrees or less, more preferably 110 degrees or more and 130 degrees or less, and even more preferably 115 degrees or more and 125 degrees or less. In this case, the closer the absolute value of the difference in the relative reflection phase of the electromagnetic waves is to 120 degrees, the more the disturbance of the wavefront of the reflected waves can be suppressed.

[0046] In the dielectric layer, the difference between the round-trip optical path length in the first region and the round-trip optical path length in the second region is designed so that the absolute value of the difference between the relative reflection phase of the electromagnetic wave in the first region and the relative reflection phase of the electromagnetic wave in the second region is set as described above. Furthermore, the thicknesses of the first region and the second region are each set so that the difference between the round-trip optical path length in the first region and the round-trip optical path length in the second region is the difference described above. The thicknesses of the first region and the second region are each set appropriately depending on the wavelength of the electromagnetic wave, the dielectric constant of the material of the dielectric layer, and the desired reflection characteristics. For example, the effective wavelength of the electromagnetic wave passing through the dielectric is λ ｇWhen the thickness of the base is α, the thicknesses of the first and second regions are α+0λ or more and α+λ ｇ As described above, when only one dielectric layer is used, the thickness of the second region is preferably about α+λ ｇ On the other hand, in the above case, the thickness of the second region is preferably about α+λ ｇ The thickness α of the base can be set to the same thickness as the first region. The thickness α of the base is set appropriately taking into consideration the overall strength, ease of formation, etc., but is usually set to 0.1λ / 10 or more in consideration of the effect on electromagnetic waves. ｇ Specifically, the wavelength λ of the electromagnetic wave in the air is preferably about 1 / 2 or less. ０ When the thickness of the first region is 10 mm and the dielectric constant of the dielectric layer is 2.57, the thicknesses of the first region and the second region are preferably 0 mm or more and 8.9 mm or less, and more preferably 0 mm or more and 4.2 mm or less. In this case, the thickness of the second region is further preferably 1.2 mm or more.

[0047] In particular, it is preferable that the thickness of the first region is 0. When the thickness of the first region is 0, the dielectric layer can be formed more easily. Note that when the thickness of the first region is 0, this means that no dielectric layer is formed in the first region located on the reflective member.

[0048] The pitch of the first region or the second region is appropriately set according to the desired reflection characteristics. The pitch of the first region is shifted by one wavelength (phase difference: 360 degrees) per pitch. Similarly, the pitch of the second region is shifted by one wavelength (phase difference: 360 degrees) per pitch. Therefore, the reflection angle can be adjusted by the pitch of the first region or the second region. For example, by shortening the pitch of the first region or the second region, the difference in the reflection angle from the specular reflection angle can be increased, while by lengthening the pitch of the first region or the second region, the difference in the reflection angle from the specular reflection angle can be reduced.

[0049] Furthermore, when the reflective member is a member in which a plurality of reflective elements are arranged, the pitch of the first region or the second region of the dielectric layer may be the same as or different from the pitch of the reflective elements of the reflective member. If the pitch of the first region or the second region of the dielectric layer is the same as the pitch of the reflective elements of the reflective member, the design is easier. Furthermore, for example, by adjusting the pitch of the first region or the second region of the dielectric layer, the control range of the reflection characteristics can be expanded regardless of the pitch of the reflective elements of the reflective member.

[0050] The pitch of the first regions or second regions throughout the dielectric layer is appropriately designed depending on the desired reflection characteristics, and may be uniform or non-uniform.

[0051] The pitch of the first regions refers to the distance from the center of one first region to the center of an adjacent first region, and the pitch of the second regions refers to the distance from the center of one second region to the center of an adjacent second region.

[0052] The sizes of the first and second regions are set appropriately.

[0053] The sizes of the first and second regions are appropriately designed in accordance with the desired reflection characteristics throughout the dielectric layer, and may be uniform or non-uniform.

[0054] The planar shapes of the first and second regions are not particularly limited as long as they allow the first and second regions to be arranged without gaps.

[0055] In the entire dielectric layer, the shapes of the first region and the second region in plan view may be uniform or non-uniform.

[0056] The pattern shape of the first region and the second region is not particularly limited, and may be, for example, a stripe shape.

[0057] In the dielectric layer, the arrangement of the first and second regions is appropriately determined depending on the desired reflection characteristics. Typically, the first and second regions are arranged alternately. For example, when the frequency selective reflector has a rectangular shape in a planar view, the first and second regions may be arranged alternately in the vertical or horizontal direction, or may be arranged alternately in a diagonal direction. For example, FIG. 4 shows an example in which the first regions 311 and the second regions 312 are arranged alternately in the horizontal direction (direction D1) in the figure. FIG. 1( a) also shows an example in which the first regions 311 and the second regions 312 are arranged alternately in a diagonal direction in the figure. Furthermore, when the first and second regions are arranged without gaps, the arrangement direction is not particularly limited. The first and second regions may be arranged by selecting an appropriate arrangement angle and an appropriate arrangement direction according to the required reflection characteristic design.

[0058] The first and second regions may be arranged alternately in a concentric pattern, for example. In this case, the number of concentric circles may be one or more.

[0059] The first and second regions may be arranged in an island-in-a-sea fashion, for example, where the first region may be the sea and the second region may be the island, or the first region may be the island and the second region may be the sea.

[0060] In the dielectric layer of this embodiment, the thickness of the first and second regions affects the overall reflection characteristics of the frequency selective reflector, but the pitch of the first or second regions, the size of the first and second regions, the planar shapes of the first and second regions, the pattern shapes of the first and second regions, etc. can also affect the overall reflection characteristics of the frequency selective reflector. Specifically, examples of these include adjustment of polarization characteristics and effects on beam profiles (high directivity, diffusion, multi-beam, etc.).

[0061] In the dielectric layer, the thickness distribution of the dielectric layer is appropriately selected and multiple first regions and second regions are arranged so that the normal vector of the same phase plane of the reflected wave relative to the incident wave incident at a predetermined incident angle is in the desired reflection direction.

[0062] For example, when an incident plane wave is reflected in a single direction, i.e., as a so-called plane wave, it is preferable that the pitch of the first or second region, the width of the first and second regions, and the planar shape of the first and second regions are uniform throughout the dielectric layer. In this case, it is more preferable that the pattern shape of the first and second regions is striped. For example, in FIG. 4 , the pitch of the first region 311 or the second region 312, the width of the first and second regions 311 and 312, and the planar shape of the first and second regions 311 and 312 are uniform throughout the dielectric layer 305. Furthermore, the pattern shape of the first region 311 and the second region 312 is striped. In this case, as illustrated in FIG. 2 , an incident wave W1 incident at a predetermined incident angle θ1 can be reflected at a predetermined reflection angle θ2, and the reflected wave W2 can be a plane wave with no spreading. Furthermore, when the frequency selective reflector has a rectangular shape in a plan view and the pattern shape of the first and second regions is striped, the longitudinal direction of the stripes in the first and second regions may be parallel to the short-side direction of the frequency selective reflector, or the longitudinal direction of the stripes in the first and second regions may be parallel to the long-side direction of the frequency selective reflector. In an actual frequency selective reflector, the longitudinal and short-side directions of the stripes in the first and second regions can be set arbitrarily depending on the design of the reflection characteristics.

[0063] Furthermore, for example, when electromagnetic waves are diffused, for example, reflected as cylindrical waves, the dielectric layer may have multiple periodic structures with different reflection characteristics. For example, in FIG. 5A, the dielectric layer 305 has three types of periodic structures 321-323. These periodic structures 321-323 differ from one another in the widths w31, w33, and w35 of the first region 311, the widths w32, w34, and w36 of the second region 312, and the pitches p31, p32, and p33 of the second region 312. This results in different reflection characteristics for the three types of periodic structures 321-323. Furthermore, as shown in FIG. 5B, the relative reflection phases of electromagnetic waves in the first region 311 and the second region 312 of the dielectric layer 305 are 0 degrees (-360 degrees) and -180 degrees, respectively. The patterns of the first region 311 and the second region 312 are striped. In this case, as illustrated in FIG. 6, an incident wave W1 incident at a predetermined incident angle θ1 can be reflected at reflection angles θ2, θ2', and θ2" according to the periodic structure, and can be reflected with a widening effect, thereby widening the wavefront of a reflected wave W2.

[0064] Furthermore, for example, when a spherical wave is reflected as a plane wave, the pattern shape of the first region and the second region is preferably an arc stripe shape.

[0065] The dielectric layer may also have multiple regions with different reflection characteristics, and the multiple regions may be arranged in a plane. For example, in FIG. 7 , the dielectric layer 305 has two types of regions 331 and 332 with different reflection characteristics, and the two types of regions 331 and 332 are arranged in a plane. These regions 331 and 332 differ from each other in, for example, the width of the first region 311, the width of the second region 312, and the pitch of the second region 312. This results in the two types of regions 331 and 332 having different reflection characteristics. This aspect can accommodate multiple coverage holes.

[0066] Furthermore, for example, when the reflecting member described below is a frequency selective surface having multiple types of frequency selective surfaces (FSS) that selectively reflect electromagnetic waves in different frequency bands, the reflection characteristics of the dielectric layer may be designed according to the frequency selectivity of the frequency selective surfaces, and the dielectric layer may have regions with different reflection characteristics. In this case, too, an arrangement such as that shown in FIG. 7 may be used. In this embodiment, dual bands or more bands can be supported.

[0067] Furthermore, when the incident wave and the reflected wave are plane waves, the dielectric layer has a periodic structure in which the first and second regions are repeatedly arranged. The term "periodic structure" refers to a structure in which the first and second regions are periodically and repeatedly arranged. In a periodic structure in which the first and second regions have the same reflection characteristics, the widths of the first and second regions, the pitch of the first or second regions, the planar shapes of the first and second regions, the pattern shapes of the first and second regions, and the like can be the same. Even when the dielectric layer has a periodic structure, as described above, periodic structures with different reflection characteristics can be combined. In this case, the reflection characteristics of the combined periodic structures are appropriately designed according to the desired reflection characteristics. Specifically, the widths of the first and second regions, the pitch of the first or second regions, the planar shapes of the first and second regions, the pattern shapes of the first and second regions, and the like in the combined periodic structures are appropriately set according to the desired reflection characteristics.

[0068] Generally, in designing reflection characteristics to reflect a plane wave as a plane wave in a direction different from the specular reflection direction, the reflection characteristics can be decomposed into the incident and reflection characteristics in the in-plane x direction and in-plane y direction of the reflector, and then converted into reflection phase distributions in the x and y directions, and incorporated as the thickness distribution of the dielectric layer. For example, as shown in Figure 8, a portion of a frequency selective reflector in which 10 x 10 (i = 10, j = 10) areas of the same size that can individually adjust the reflection phase are arranged will be described as an example. The angle of incidence (θ ｉｎ , φ ｉｎ ) is reflected from the direction of the reflected wave (θ ｏｕｔ , φ ｏｕｔ) the reflection phase δ required in the region at position (i, j) when a plane wave is reflected in the direction ｉ，ｊ is given by the following equation:

[0069] δ i,j =2π{p×i×(sinθ out ×cosφ out -sinθ in ×cosφ in )+p×j×(sinθ out ×sinφ out -sinθ in ×sinφ in )} / λ where, in the above formula, δ ｉ，ｊ : Reflection phase of the cell area at position (i, j) relative to the phase center (0, 0) λ: Wavelength of the reflected wave [m] p: Size of the area [m] θ ｉｎ : θ gradient of incident wave φ ｉｎ : Incident wave φ gradient θ ｏｕｔ : θ gradient of reflected wave φ ｏｕｔ : Indicates the φ gradient of the reflected wave.

[0070] The dielectric layer may be, for example, a single layer or multiple layers. The dielectric layer may have a base portion serving as a base and an uneven portion disposed on the base portion. The dielectric layer may be, for example, a single member in which all of the first regions and second regions are integrally formed, or may be a member in which the individual first regions and second regions are formed separately and arranged in block form.

[0071] (2) Characteristics of the Dielectric Layer The dielectric layer is only required to transmit electromagnetic waves in a specific frequency band, and may or may not transmit electromagnetic waves in other frequency bands.

[0072] The dielectric loss tangent of the dielectric layer is preferably relatively small. A small dielectric loss tangent of the dielectric layer can reduce dielectric loss and high-frequency loss. Specifically, the dielectric loss tangent of the dielectric layer for electromagnetic waves of the target frequency is preferably 0.01 or less. Furthermore, the smaller the dielectric loss tangent of the dielectric layer, the more preferable it is, and there is no particular limit on the lower limit.

[0073] Furthermore, it is preferable that the dielectric layer has a relatively high dielectric constant. A high dielectric constant of the dielectric layer is expected to have the effect of allowing the thickness of the dielectric layer to be thin. Specifically, the dielectric constant of the dielectric layer for electromagnetic waves of the target frequency is preferably 2 or more, more preferably 2.5 or more, and even more preferably 3 or more when the difference between the reflection angle and the specular reflection angle is large.

[0074] The dielectric loss tangent and dielectric constant of the dielectric layer are measured by a resonator method in accordance with JIS C2138:2007.

[0075] (3) Dielectric Layer Material The material of the dielectric layer is not particularly limited as long as it is a dielectric that can transmit a predetermined electromagnetic wave, and examples thereof include resin, glass, quartz, and ceramics. In other words, the dielectric layer may contain resin. Among these, resin is preferred in view of the ease of forming the dielectric layer.

[0076] The resin is not particularly limited as long as it can transmit predetermined electromagnetic waves, but it is preferable that the resin has relatively little absorption of the electromagnetic waves and relatively high transmittance of the electromagnetic waves. Furthermore, it is preferable that the resin satisfy the above-mentioned dielectric loss tangent, and more preferably the above-mentioned dielectric constant. Examples of such resins include polycarbonate, acrylic resin, ABS resin, PLA resin, olefin-based resin, and copolymers thereof. Among these, polycarbonate is preferred because of its excellent dimensional stability and low high-frequency loss.

[0077] The dielectric layer may further contain a filler. By containing the filler in the dielectric layer, the dielectric constant and mechanical strength of the dielectric layer can be adjusted. The dielectric constant of the filler is preferably higher than the dielectric constant of the resin. This allows the dielectric constant of the dielectric layer to be increased, and the required thickness of the dielectric layer to be reduced. The high-dielectric-constant filler is not particularly limited, and examples thereof include inorganic particles such as glass and silica, and fine fibers.

[0078] The material, shape, size, and content of the filler can be appropriately selected based on the desired dielectric constant, mechanical strength, degree of dispersibility, etc. The size of the filler must be sufficiently smaller than the effective wavelength of the electromagnetic wave passing through the dielectric. The effective wavelength of the electromagnetic wave is λ ｇ In this case, the diameter of the filler equivalent to a sphere is, for example, 0.01λ ｇ The following is preferable. However, as the size of the filler approaches the nanometer order, uniform dispersion tends to become difficult, which may increase the load on the processing process. Furthermore, the content of the filler in the dielectric layer varies depending on the combination of the dielectric and filler materials, the shape and size of the filler, etc., and is adjusted appropriately.

[0079] Furthermore, when the dielectric layer is formed by molding using a mold, for example, a release agent or an antistatic agent may be added to the dielectric layer. These may be selected from commonly used agents as appropriate. Furthermore, it is preferable that the dielectric layer does not contain additives or fillers that impart conductivity, such as carbon black or metal particles.

[0080] (4) Supporting Portion In this embodiment, when the thickness of the first region is zero, the dielectric layer can have a supporting portion that supports the second region. For example, in FIGS. 9(a) and 9(b), the thickness t31 of the first region 311 is zero, and the dielectric layer 305 has a supporting portion 309 that supports the second region 312. Note that FIG. 9(b) is a cross-sectional view taken along line A-A in FIG. 9(a). By having the supporting portion in the dielectric layer, the strength can be increased. Furthermore, when the thickness of the first region is zero, the supporting portion can integrate multiple second regions together, making it easier to form the dielectric layer.

[0081] The position of the support portion is not particularly limited as long as it can connect the second regions and integrate the second regions. The support portion is preferably disposed at least on the outer periphery of the dielectric layer. The support portion may also be disposed inside the dielectric layer other than on the outer periphery. For example, in FIG. 9( a), the support portion 309 is disposed on the outer periphery and inside of the dielectric layer 305.

[0082] The thickness of the support portion can be the same as the thickness of the second region. In this case, the second region and the support portion can be formed simultaneously. Furthermore, the thickness of the support portion located on the outer periphery of the dielectric layer may be greater than the thickness of the second region. As described below, when a first dielectric layer and a second dielectric layer are stacked in order from the reflecting member side, the thickness of the support portion located on the outer periphery of the second dielectric layer only for the second dielectric layer may be greater than the thickness of the second region. As described below, when a cover member is disposed on the surface of the dielectric layer opposite the reflecting member, the cover member can be supported by the support portion by making the thickness of the support portion located on the outer periphery of the dielectric layer greater than the thickness of the second region.

[0083] The width of the support portion is preferably a width that does not affect the reflection characteristics. When the thickness of the support portion is approximately the same as the thickness of the second region, the width of the support portion is preferably λ or less, and more preferably λ / 2 or less, where λ is the wavelength of the electromagnetic wave. If the width of the support portion is too large, it may affect the reflection characteristics. Furthermore, if the width of the support portion is λ / 2 or less, resonance is unlikely to occur, and the reflection intensity of the electromagnetic wave will drop sharply. On the other hand, the lower limit of the width of the support portion is not particularly limited as long as it is a width that can support the second region.

[0084] Specifically, the width of the support portion is preferably 0.05 mm or more and 2 mm or less, more preferably 0.1 mm or more and 1 mm or less, and even more preferably 0.2 mm or more and 0.5 mm or less. If the width of the support portion is too small, it may be difficult to form the support portion or to support the second region. Furthermore, if the width of the support portion is too large, it may affect the reflection characteristics.

[0085] The support portions located on the periphery of the dielectric layer are thought not to affect the reflection characteristics, and therefore the width of the support portions located on the periphery of the dielectric layer is not particularly limited and may be within the above range or may be outside the above range.

[0086] The width of the support portion located on the outer periphery of the dielectric layer may be the same as or different from the width of the support portion located inside the dielectric layer other than the outer periphery.

[0087] Furthermore, the ratio of the total area of ​​the support portions to the outer area of ​​the dielectric layer is preferably 30% or less, more preferably 20% or less, and even more preferably 10% or less. If this ratio is too high, the performance of the frequency selective reflector may be reduced. On the other hand, the lower limit of this ratio is not particularly limited as long as the support portions can support the second region. In this case, as described above, the support portions located on the outer periphery of the dielectric layer are not considered to affect the reflection characteristics, and therefore are not included in the total area of ​​the support portions.

[0088] Here, the ratio of the total area of ​​the supporting portions to the outer area of ​​the dielectric layer is measured by the following method. First, a region having a size of 1 / 16 of the entire dielectric layer is randomly selected. The ratio of the total area of ​​the supporting portions to the area of ​​this selected region is calculated. If the ratio is within the above range, the ratio in the selected region is considered to be the ratio of the total area of ​​the supporting portions to the outer area of ​​the dielectric layer. On the other hand, if the ratio exceeds the above range, the ratio of the total area of ​​the supporting portions to the outer area of ​​the dielectric layer is calculated for the entire dielectric layer. The outer area of ​​the dielectric layer refers to the area of ​​the region surrounded by the outermost outline of the dielectric layer when viewed from above. For example, as shown in FIG. 1A, when the thickness of the first region of the dielectric layer is zero, the region surrounded by the outermost outline of the dielectric layer when viewed from above is the region surrounded by the outermost outline of the region combining the first and second regions, i.e., a rectangular region including the shaded portion of the second region in FIG. 1A, and the outer area of ​​the dielectric layer is the area of ​​this rectangular region.

[0089] In particular, it is preferable that the width of the supporting portion is within the above range, and the ratio of the total area of ​​the supporting portion to the outer area of ​​the dielectric layer is within the above range.

[0090] The planar shape of the support portion is not particularly limited. The planar shape of the support portion located on the outer periphery of the dielectric layer is appropriately selected depending on the outer shape of the dielectric layer, and may be, for example, a frame shape. The planar shape of the support portion located inside the dielectric layer may be, for example, a lattice shape or a stripe shape.

[0091] (5) Multiple Dielectric Layers In this embodiment, when the thickness of the first region of the dielectric layer is 0, two dielectric layers may be disposed one on top of the other in the thickness direction.

[0092] In the following, when two dielectric layers are arranged stacked in the thickness direction, one of the two dielectric layers located on the reflective member side may be referred to as the first dielectric layer, and the other dielectric layer may be referred to as the second dielectric layer.

[0093] 10(a) and 10(b) are a schematic plan view and a cross-sectional view illustrating the first dielectric layer 305a. FIGS. 11(a) and 11(b) are a schematic plan view and a cross-sectional view illustrating the second dielectric layer 305b. FIG. 12(a) shows an example in which the first dielectric layer 305a and the second dielectric layer 305b are stacked in the thickness direction. As shown in FIG. 12(a), the first dielectric layer 305a and the second dielectric layer 305b are arranged in this order from the reflective member 2 side. As shown in FIGS. 10(a) and 10(b), the first dielectric layer 305a has a plurality of thin first regions 311a with a thickness t31 and a plurality of thick second regions 312a with a thickness t32. The thickness t31 of the first regions 311a is 0. 11A and 11B, the second dielectric layer 305b has a plurality of first regions 311b each having a thickness t33 and a plurality of second regions 312b each having a thickness t34. The thickness t33 of the first regions 311b is 0.

[0094] 12(b) is a graph in which the horizontal axis represents the position in the predetermined direction D1 of the first dielectric layer 305a and the second dielectric layer 305b, and the vertical axis represents the relative reflection phase of the electromagnetic wave when the electromagnetic wave passes through the first dielectric layer 305a and the second dielectric layer 305b, is reflected by the reflecting member 2, passes through the first dielectric layer 305a and the second dielectric layer 305b again, and is emitted toward the electromagnetic wave incident side, with the value of the relative reflection phase of the electromagnetic wave being between −360 degrees and 0 degrees, and is an example of the relative reflection phase of the electromagnetic wave in the first region and the second region of the dielectric layer in the frequency selective reflector shown in FIG. 12(b). As shown in FIG. 12(b), the relative reflection phase of the electromagnetic wave in the region where the first region 311a of the first dielectric layer 305a and the first region 311b of the second dielectric layer 305b overlap is 0 degrees (−360 degrees). The relative reflection phase of the electromagnetic wave in the region where the second region 312b of the first dielectric layer 305a and the first region 311b of the second dielectric layer 305b overlap is −120 degrees. The relative reflection phase of the electromagnetic wave in the region where the second region 312a of the first dielectric layer 305a and the second region 312b of the second dielectric layer 305b overlap is −240 degrees.

[0095] When two dielectric layers are arranged one on top of the other in the thickness direction, by setting the thickness of the first region of the first dielectric layer and the first region of the second dielectric layer to zero and varying the thickness of the second region of the first dielectric layer and the second region of the second dielectric layer, the round-trip optical path length in the dielectric layers can be changed in the region where the first region of the first dielectric layer and the first region of the second dielectric layer overlap, the region where the second region of the first dielectric layer and the first region of the second dielectric layer overlap, and the region where the second region of the first dielectric layer and the second region of the second dielectric layer overlap, thereby controlling the reflection phase of the electromagnetic wave, thereby controlling the reflection direction of the electromagnetic wave relative to a predetermined incident direction to any direction.

[0096] Regarding the arrangement of the first dielectric layer and the second dielectric layer, it is preferable that the first region and the second region of the first dielectric layer and the first region and the second region of the second dielectric layer are arranged so that the second region of the second dielectric layer is not located on the first region of the first dielectric layer and so that the second region of the second dielectric layer is located partially on the second region of the first dielectric layer.

[0097] (6) Method for Forming Dielectric Layer The method for forming the dielectric layer is not particularly limited as long as it is capable of forming a dielectric layer having two different thicknesses. Examples include cutting a resin sheet, laser processing, molding using a mold, modeling using a 3D printer, and joining small pieces. Forming methods that do not use a mold, such as cutting, laser processing, or 3D printing, can be easily customized to the desired reflection angle, making them suitable for special installation situations or for design tuning when designing and developing large-scale frequency selective reflectors that are difficult to simulate. When molding using a mold, molding may be performed on a substrate made of a dielectric. In this case, the substrate and the molding resin may be made of different materials as long as they are transparent to the specified electromagnetic waves. Furthermore, for example, when the reflective member and the dielectric layer are designed and manufactured separately, if multiple types of dielectric layers having reflection characteristics with predetermined angles of incidence and reflection angles are prepared in advance, the type of dielectric layer is selected according to the situation, and the dielectric layer is rotated in-plane around the normal direction as an axis to fine-tune the reflection direction of the electromagnetic waves, it may be more cost-effective to manufacture dielectric layers of the same specifications collectively, and in such cases a molding technique using a mold is preferred.

[0098] Among these, cutting and laser processing of resin sheets are preferred. This significantly reduces manufacturing costs and shortens manufacturing time. It also makes it possible to use highly durable materials such as engineering plastics, which are not well suited for molding or 3D printing.

[0099] 2. Reflecting Member The reflecting member in this embodiment is a member that reflects electromagnetic waves in a specific frequency band.

[0100] The reflective member is not particularly limited as long as it reflects electromagnetic waves in a specific frequency band, and may be, for example, a member that reflects only electromagnetic waves in a specific frequency band, or a member that reflects not only electromagnetic waves in a specific frequency band but also electromagnetic waves in other frequency bands. In particular, it is preferable that the reflective member has a wavelength selection function that reflects only electromagnetic waves in a specific frequency band.

[0101] An example of a reflective member that reflects not only electromagnetic waves in a specific frequency band but also electromagnetic waves in other frequency bands is a reflective layer disposed on the entire surface of a frequency selective reflector. For example, Fig. 13(a) shows an example in which the reflective member 2 is a reflective layer 7. In Fig. 13(a), the reflective layer 7 is disposed on the entire surface of the frequency selective reflector 1. Furthermore, as shown in Fig. 13(b), the reflective member 2 may have a dielectric substrate 4 and a reflective layer 7 disposed on the entire surface of the dielectric substrate 4. In this case, the reflective layer 7 may also serve as a ground layer 310, as will be described later.

[0102] The reflective layer is not particularly limited as long as it can reflect electromagnetic waves in a specific frequency band, and examples thereof include conductive films such as metal films, metal oxide films, carbon films, metal meshes, etc. Examples of metal oxide films include ITO, IZO, AZO, GZO, ATO, etc.

[0103] The thickness of the reflective layer is not particularly limited as long as it is a thickness that can reflect electromagnetic waves in a specific frequency band, and may be set appropriately.

[0104] Furthermore, the reflecting member that reflects only a specific frequency band may be anything that has a wavelength selection function that reflects only electromagnetic waves in a specific frequency band, and an example of such a member is a frequency selective plate.

[0105] A frequency selective surface (FSS) has a frequency selective surface (FSS) that controls the reflection and transmission of electromagnetic waves in a specific frequency band. When functioning as a reflector for electromagnetic waves in a specific frequency band, the FSS has a plurality of reflective elements (scattering elements) arranged within its surface. An example of a frequency selective surface is one that has a dielectric substrate and a plurality of reflective elements arranged on the surface of the dielectric substrate facing the dielectric layer. For example, FIG. 3 shows an example in which the reflective member 2 is a frequency selective surface, and the reflective member 2 has a dielectric substrate 4 and a plurality of reflective elements 3 arranged on the surface of the dielectric substrate 4 facing the dielectric layer 305. The frequency selective surface can be appropriately selected from known frequency selective surfaces.

[0106] The shape of the reflective element that forms the frequency selective surface is not particularly limited, and can be any shape, such as a ring, cross, square, rectangular, circular, elliptical, rod-shaped, a planar pattern such as a pattern divided into multiple adjacent regions, or a three-dimensional structure using a through-hole via or the like.

[0107] The reflecting element may be, for example, a single layer or a multilayer. When the reflecting element is a single layer, the frequency selective surface may be, for example, one in which a plurality of reflecting elements are arranged on one side of a dielectric substrate. When the reflecting element is a multilayer, the frequency selective surface may be, for example, one in which a plurality of reflecting elements are arranged on both sides of a dielectric substrate, one in which a dielectric substrate and a plurality of reflecting elements are arranged in this order, and one in which a one-sided conductor is arranged on the surface farthest from the surface on which the electromagnetic wave is incident.

[0108] Furthermore, it is preferable that the frequency selective surface, i.e., the reflecting member, has a reflection phase control function that controls the reflection phase of the electromagnetic wave. In such a reflecting member, the resonant frequency of each reflecting element can be changed by changing the dimensions and shape of the reflecting elements, thereby controlling the reflection phase of the electromagnetic wave. That is, the reflecting member may have multiple types of reflecting elements with different dimensions. Therefore, when the frequency selective surface has a reflection phase control function, the reflection characteristics of the electromagnetic wave can be controlled by controlling the reflection phase distribution of the electromagnetic wave through the thickness of the dielectric layer and the dimensions and shape of the reflecting elements. Therefore, for example, the reflection characteristics in two orthogonal directions (e.g., the x-axis direction and the y-axis direction) within the plane of the frequency selective reflecting plate can be individually designed using the frequency selective surface and the dielectric layer, and desired electromagnetic wave reflection characteristics can be obtained while minimizing the thickness of the dielectric layer.

[0109] A general frequency selective surface can be applied as a frequency selective surface with a reflection phase control function. Although there are advantages and disadvantages to each design, all of them can change the reflection phase of electromagnetic waves by changing the size and shape of the reflecting element.

[0110] The different dimensions of the reflective elements are appropriately selected depending on the shape of the reflective elements.

[0111] 3. Control of the Reflection Direction of Electromagnetic Waves In the frequency selective reflector of this embodiment, by changing the thicknesses of the first and second regions of the dielectric layer, the round-trip optical path length in the dielectric layer between the first and second regions can be changed, thereby controlling the relative reflection phase of the electromagnetic wave. Furthermore, by adjusting the pitch of the first or second region, the size of the first and second regions, the pattern shape of the first and second regions, etc., in addition to the thicknesses of the first and second regions, the reflection direction of electromagnetic waves incident from a predetermined direction can be controlled.

[0112] Furthermore, when the reflecting member is a frequency selective plate and also a member having a reflection phase control function, not only can the round-trip optical path length in the dielectric layer be changed between the first and second regions by changing the thickness of the first and second regions of the dielectric layer, but also the resonant frequency of each reflecting element can be changed by changing the dimensions and shape of the reflecting elements of the reflecting member, thereby controlling the reflection phase of the electromagnetic wave, thereby expanding the design freedom for controlling reflection characteristics.

[0113] In this case, it is possible to separate the reflection control direction of the reflecting member from the reflection control direction of the dielectric layer, and perform two-dimensional reflection direction control with the entire frequency selective reflector. Also, if the reflection control directions of the reflecting member and the dielectric layer are overlapped, for example, it is possible to realize a reflection phase distribution that reflects in a certain direction to a certain extent with the reflecting member, and then fine-tune it with the dielectric layer. In this case, there is an advantage that the thickness of the dielectric layer can be made thinner.

[0114] As an example of the arrangement of the thickness distribution of the dielectric layer and the size distribution of the reflecting elements of the reflecting member, as shown in FIG. 14 , the dielectric layer 305 and the reflecting member 2 can be arranged so that the thickness of the dielectric layer 305 increases as the size of the reflecting elements 3 of the reflecting member 2 increases. In this embodiment, the thickness of the dielectric layer can be reduced. This reduces the thickness of the dielectric layer, thereby reducing the weight and cost of the frequency selective reflector. Furthermore, even if the reflection angle increases, the reflected wave is less likely to hit the dielectric layer.

[0115] Furthermore, as an arrangement of the thickness distribution of the dielectric layer and the size distribution of the reflective elements of the reflective member, for example, as shown in Figure 15, the dielectric layer 305 and the reflective member 2 may be arranged so that the size of the reflective elements 3 of the reflective member 2 increases along the direction D2, and the thickness of the dielectric layer 305 increases along the direction D2.

[0116] In FIG. 15, since the dimensions of the reflecting elements are different, the relative reflection phase of the electromagnetic wave in the unit area where each reflecting element is arranged will differ depending on the dimensions of the reflecting element.

[0117] Furthermore, in the case of a specification in which the reflecting member and the dielectric layer are designed separately and then combined, the direction of reflection of the electromagnetic wave can be fine-tuned by rotating the dielectric layer in-plane relative to the reflecting member around the normal direction as an axis, and adjusting the arrangement direction of the first and second regions of the dielectric layer relative to the reflecting member.

[0118] Furthermore, as described above, the reflection characteristics can be controlled by adjusting the pitch of the first or second regions in the dielectric layer. For example, by shortening the pitch of the first or second regions, the reflection angle of the electromagnetic wave can be increased, while by lengthening the pitch of the first or second regions, the reflection angle of the electromagnetic wave can be decreased.

[0119] As described above, the in-plane arrangement of the first and second regions of the dielectric layer that realizes the in-plane distribution design of the reflection phase in the frequency selective reflector does not need to have a fixed positional relationship with the in-plane arrangement of the reflecting elements of the reflecting member, and the reflection characteristics are not significantly affected even if the first and second regions of the dielectric layer are arranged offset from the in-plane arrangement of the reflecting elements. Therefore, when the reflecting member is a frequency selective plate and a member that has a reflection phase control function, it is possible to design the dielectric layer and the reflecting member independently.

[0120] 4. Other Configurations The frequency selective reflector of this embodiment may have other configurations as needed in addition to the above-described reflecting member and dielectric layer.

[0121] (1) Adhesive Layer The frequency selective reflector of this embodiment may have an adhesive layer between the reflecting member and the dielectric layer. The adhesive layer can bond the reflecting member and the dielectric layer. Furthermore, when the reflecting member is a member in which a plurality of reflecting elements are arranged, the adhesive layer can flatten the unevenness caused by the reflecting elements, thereby suppressing the influence of the unevenness caused by the reflecting elements when laminating the dielectric layer on the reflecting member. For example, in FIG. 1(b), an adhesive layer 306 is disposed between the reflecting member 2 and the dielectric layer 305.

[0122] The adhesive layer can be made of, for example, an adhesive or a pressure-sensitive adhesive, and can be appropriately selected from known adhesives and pressure-sensitive adhesives. In this case, the adhesive or pressure-sensitive adhesive must be non-conductive. Furthermore, if the adhesive or pressure-sensitive adhesive is liquid, it is preferable that it can be spread evenly and has fluidity sufficient to remove trapped air bubbles. Furthermore, if the adhesive or pressure-sensitive adhesive is in sheet form, it is preferable that it has a uniform thickness and flexibility sufficient to conform to the unevenness of the bonding interface and prevent trapped air bubbles.

[0123] The thickness of the adhesive layer is preferably a thickness that can obtain the desired adhesive strength and is uniform. Furthermore, when the reflective member is a member in which a plurality of reflective elements are arranged, the thickness of the adhesive layer is preferably equal to or greater than the thickness of the reflective elements from the viewpoint of flattening. In this case, if the adhesive layer is thicker than the thickness of the reflective elements, the reflective elements will be embedded in the adhesive layer. Furthermore, the thickness of the adhesive layer is preferably sufficiently smaller than the effective wavelength of the target electromagnetic wave, and the effective wavelength of the electromagnetic wave is preferably set to λ ｇ Specifically, 0.01λ ｇ It is preferable that:

[0124] (2) Space The frequency selective reflector of this embodiment may have a space between the reflecting member and the dielectric layer. For example, in Fig. 16, a space 8 is provided between the reflecting member 2 and the dielectric layer 305.

[0125] When a space is provided between the reflecting member and the dielectric layer, it is preferable that the distance between the reflecting member and the dielectric layer is constant, so that the optical path length in the space can be made uniform.

[0126] (3) Covering Member The frequency selective reflector of this embodiment may have a covering member on the surface of the dielectric layer opposite to the reflecting member. The covering member can protect the dielectric layer. The covering member can also impart design features.

[0127] Furthermore, when a cover member is disposed, a frame-shaped spacer for supporting the cover member may be further disposed on the outer periphery of the dielectric layer.

[0128] (4) Ground Layer The frequency-selective reflector of this embodiment may have a ground layer on the surface of the reflecting member opposite the dielectric layer. Furthermore, if the reflecting member reflects electromagnetic waves in not only a specific frequency band but also other frequency bands, i.e., does not have wavelength selectivity, the reflecting member may have a reflective layer that also serves as the ground layer. The ground layer can block interference with objects present on the back surface of the frequency-selective reflector and suppress noise generation. For example, in FIG. 17 , a ground layer 310 is disposed on the surface of the reflecting member 2 opposite the dielectric layer 305. Furthermore, as shown in FIG. 13( b ), the reflecting member 2 may have a dielectric substrate 4 and a reflective layer 7 disposed on the entire surface of the dielectric substrate 4, and the reflective layer 7 may also serve as the ground layer 310. The ground layer may also be part of a reflective member that does not have wavelength selectivity. If the reflective member does not have wavelength selectivity, the reflective member will also reflect electromagnetic waves other than those in the specific frequency band. However, by using the structure of the dielectric layer designed for electromagnetic waves in the intended specific frequency band, the reflective member can reflect electromagnetic waves in the specific frequency band in the intended direction, and can therefore function as a frequency-selective reflector.

[0129] The ground layer may be made of a general conductive film such as a metal film, a metal mesh, a carbon film, or an ITO film.

[0130] (5) Planarizing Layer The frequency selective reflector of this embodiment may have a planarizing layer between the reflecting member and the dielectric layer. When the reflecting member is a member in which a plurality of reflecting elements are arranged, the planarizing layer can flatten the unevenness caused by the reflecting elements, thereby suppressing the influence of the unevenness caused by the reflecting elements when the dielectric layer is laminated on the reflecting member. The planarizing layer here refers to a layer disposed separately from the adhesive layer, and an example of such a layer is an ionizing radiation cured resin layer disposed in a state in which the reflecting elements are embedded. Furthermore, when a space is provided between the reflecting member and the dielectric layer, the planarizing layer may have the function of protecting the reflecting elements.

[0131] (6) Fixing Layer When the frequency selective reflector of this embodiment is used by attaching it to, for example, a wall, a fixing layer having a mechanism for attaching the frequency selective reflector may be disposed on the surface of the reflecting member opposite the dielectric layer. Furthermore, to suppress interference between the fixing layer and the reflecting member and the dielectric layer, a metal layer may be disposed between the fixing layer and the reflecting member, or the fixing layer may also serve as the metal layer. Furthermore, when the frequency selective reflector of this embodiment is attached to a wall, the fixing layer may have a mechanism for varying the angle of the normal direction of the frequency selective reflector so that deviations between the designed incident direction and reflection direction of the electromagnetic wave and the actual incident direction and reflection direction of the electromagnetic wave can be corrected.

[0132] (7) Antireflection Layer Since the influence of reflection at the dielectric layer interface may be considered in the case of high frequencies, in the frequency selective reflector of this embodiment, an antireflection layer may be disposed at the interface between the dielectric layer and air, if necessary. The antireflection layer may have, for example, a multilayer structure with different dielectric constants, or may have a concavo-convex structure smaller than the wavelength of the electromagnetic wave.

[0133] (9) Interference Mitigation Layer The frequency selective reflector of this embodiment may have an interference mitigation layer on the surface of the reflecting member opposite to the dielectric layer, for mitigating changes in characteristics due to interactions with the surface on which the frequency selective reflector is installed. The interference mitigation layer is not particularly limited as long as it has a dielectric constant close to that of air and can ensure an appropriate distance that reduces the interactions between the ground surface and the reflecting member. For example, a foam such as urethane foam with a dielectric constant close to that of air can be used.

[0134] 5. Other Features of the Frequency Selective Reflector The frequency selective reflector of this embodiment reflects electromagnetic waves in a specific frequency band of 24 GHz or higher in a direction different from the direction of specular reflection. The frequency band of the electromagnetic waves is not particularly limited as long as it is 24 GHz or higher, but is preferably in the range of 24 GHz or higher and 300 GHz or lower. If the frequency band of the electromagnetic waves is in the above range, the frequency selective reflector of this embodiment can be used in fifth-generation mobile communication systems, so-called 5G.

[0135] The frequency selective reflector of this embodiment can be used, for example, as a frequency selective reflector for communications, and is particularly suitable as a frequency selective reflector for mobile communications.

[0136] II. Second Embodiment In order to reflect high-intensity electromagnetic waves into the coverage hole, a large-area reflectarray is required. However, due to limitations in manufacturing equipment, it is difficult to manufacture a large-area reflectarray.

[0137] Although not a reflectarray, in the field of display devices, tiling technology for arranging multiple display devices side by side is being developed as a technology for increasing the area of ​​the display device. Therefore, it is conceivable to increase the area of ​​the reflectarray by arranging multiple reflectarrays side by side using the tiling technology.

[0138] However, when multiple reflectarrays are arranged side by side on a substrate, if the substrate is not strong enough, the substrate may bend or flex under the weight of the reflectarrays. In such cases, the reflectarrays also bend or flex, resulting in the problem of not being able to obtain the desired reflection characteristics. Furthermore, insufficient substrate strength can also be a factor in the breakage of the tiled reflectarrays after installation. On the other hand, if the thickness of the substrate is increased in order to increase the substrate strength, the overall weight increases. This makes it difficult to install the tiled reflectarrays. There is also the concern that they may fall after installation.

[0139] The main object of this embodiment is to provide a frequency selective reflector that can reduce the manufacturing cost and time and can also be made larger in area.

[0140] The frequency selective reflector of this embodiment is a frequency selective reflector that reflects electromagnetic waves of a specific frequency band in a direction other than the specular reflection direction, and comprises a substrate, a reflecting member that is arranged on one surface of the substrate and reflects the electromagnetic waves, and a dielectric member that is arranged on the surface of the reflecting member opposite the substrate and transmits the electromagnetic waves, the dielectric member having, from the reflecting member side, a first dielectric layer and a second dielectric layer, in this order, the first dielectric layer having a plurality of first dielectric portions arranged on the surface of the reflecting member opposite the substrate, the second dielectric layer having a plurality of second dielectric portions arranged on the surface of the first dielectric layer opposite the reflecting member, the second dielectric portions being arranged so as to overlap the boundaries of adjacent first dielectric portions in a planar view, the first dielectric portions having a first dielectric pattern, and the second dielectric portions having a second dielectric pattern.

[0141] 18(a) and 18(b) are schematic cross-sectional and plan views illustrating a frequency selective reflector of this embodiment, with FIG. 18(a) being a cross-sectional view taken along line A-A in FIG. 18(b). As shown in FIGS. 18(a) and 18(b), the frequency selective reflector 1 includes a substrate 21, a reflecting member 2 disposed on one surface of the substrate 21 and reflecting electromagnetic waves in a specific frequency band, and a dielectric member 5 disposed on the surface of the reflecting member 2 opposite the substrate 21 and transmitting electromagnetic waves in the specific frequency band. The frequency selective reflector 1 may also include an adhesive member 6 between the reflecting member 2 and the dielectric member 5. The dielectric member 5 includes, from the reflecting member 2 side, a first dielectric layer 11 and a second dielectric layer 12, in this order. The first dielectric layer 11 includes two first dielectric portions 11a and 11b disposed on the surface of the reflecting member 2 opposite the substrate 21. The second dielectric layer 12 has three second dielectric portions 12a, 12b, and 12c arranged on the surface of the first dielectric layer 11 opposite to the reflecting member 2. The second dielectric portion 12b is arranged so as to overlap the boundary 11X between the adjacent first dielectric portions 11a and 11b in a plan view.

[0142] 19(a) and 19(b) are schematic plan and cross-sectional views illustrating a first dielectric portion constituting the first dielectric layer in this embodiment, and FIG. 19(b) is a cross-sectional view taken along line B-B in FIG. 19(a). The first dielectric portion 11a shown in FIGS. 19(a) and 19(b) corresponds to the first dielectric portion 11a shown in FIGS. 18(a) and 18(b). As shown in FIGS. 19(a) and 19(b), the first dielectric portion 11a has a first dielectric pattern 11P. The first dielectric portion 11a may also have a first support portion 11S that supports the first dielectric pattern 11P. In FIG. 19(a), the first support portion 11S is arranged in a frame shape around the outer periphery of the first dielectric portion 11a. The first dielectric portion 11a, except for the first dielectric pattern 11P and the first support portion 11S, forms an opening 11Q.

[0143] 20(a) and 20(b) are schematic plan and cross-sectional views illustrating a second dielectric portion constituting the second dielectric layer in this embodiment, and FIG. 20(b) is a cross-sectional view taken along line B-B in FIG. 20(a). The second dielectric portion 12a shown in FIGS. 20(a) and 20(b) corresponds to the second dielectric portion 12a shown in FIGS. 18(a) and 18(b). As shown in FIGS. 20(a) and 20(b), the second dielectric portion 12a has a second dielectric pattern 12P. The second dielectric portion 12a may also have a second support portion 12S that supports the second dielectric pattern 12P. In FIG. 20(a), the second support portion 12S is arranged in a frame shape around the outer periphery of the second dielectric portion 12a. The second dielectric portion 12a, except for the second dielectric pattern 12P and the second support portion 12S, forms an opening 12Q.

[0144] Fig. 21(a) is a schematic cross-sectional view illustrating a frequency selective reflector of this embodiment. The first dielectric portion 11a and the second dielectric portion 12a shown in Fig. 21(a) correspond to the first dielectric portion 11a and the second dielectric portion 12a shown in Fig. 18(a) and (b), and correspond to the first dielectric portion 11a shown in Fig. 19(a) and (b) and the second dielectric portion 12a shown in Fig. 20(a) and (b). As shown in Fig. 21(a), the dielectric member 5 has, from the reflecting member 2 side, an A1 region 31 that does not have the first dielectric pattern 11P and the second dielectric pattern 12P, an A2 region 32 that has only the first dielectric pattern 11P from the reflecting member 2 side, and an A3 region 33 that has the first dielectric pattern 11P and the second dielectric pattern 12P from the reflecting member 2 side.

[0145] In the dielectric member 5, the A1 region 31 does not have the first dielectric pattern 11P or the second dielectric pattern 12P, the A2 region 32 has only the first dielectric pattern 11P, and the A3 region has the first dielectric pattern 11P and the second dielectric pattern 12P. Therefore, the thickness t1 of the A1 region 31 is 0, and the thickness t1 of the A1 region 31, the thickness t2 of the A2 region 32, and the thickness t3 of the A3 region 33 are different from one another. Therefore, the A1 region 31, the A2 region 32, and the A3 region 33 have different round-trip optical path lengths when an electromagnetic wave passes through the dielectric member 5, is reflected by the reflecting member 2, passes through the dielectric member 5 again, and is emitted to the electromagnetic wave incident side. The difference in the round-trip optical path lengths in these dielectric members, i.e., the optical path difference, generates a difference in the relative reflection phase.

[0146] The explanation of the "optical path length" is the same as that of the first embodiment. The optical path length actually means the effective distance when an electromagnetic wave passes through a dielectric member.

[0147] 21(b) is a graph in which the horizontal axis represents the position in the predetermined direction D1 of the dielectric member 5, and the vertical axis represents the relative reflection phase when the electromagnetic wave passes through the dielectric member 5, is reflected by the reflecting member 2, passes through the dielectric member 5 again, and is emitted toward the electromagnetic wave incident side, with the value of the relative reflection phase of the electromagnetic wave being between −360 degrees and 0 degrees. Also, FIG. 21(b) is an example of the relative reflection phase of the electromagnetic wave in the A1 region, A2 region, and A3 region of the dielectric member in the frequency selective reflector shown in FIG. 21(a). As shown in FIG. 21(b), the relative reflection phase of the electromagnetic wave in the A1 region 31, A2 region 32, and A3 region 33 of the dielectric member 5 is 0 degrees (−360 degrees), −120 degrees, and −240 degrees, respectively.

[0148] The explanation of the "reflection phase" and the "relative reflection phase" is the same as the explanation of the "reflection phase" and the "relative reflection phase" in the first embodiment. In the explanation of the "reflection phase" and the "relative reflection phase" in the first embodiment, the "dielectric layer" is read as the "dielectric member" and the "first region and the second region of the dielectric layer" is read as the "respective regions of the dielectric member."

[0149] Furthermore, when the dielectric member has only the first and second dielectric layers as the dielectric layers, among the A1 region, A2 region, and A3 region of the dielectric member, the region with the smallest reflection phase delay is usually the A1 region, which has a thickness of 0. Furthermore, when the dielectric member has three or more dielectric layers, among the regions of the dielectric member, the region with the smallest reflection phase delay is usually the region with a thickness of 0 that does not have any of the dielectric patterns that constitute each dielectric layer.

[0150] As described above, in the dielectric member 5, the thickness t1 of the A1 region 31, the thickness t2 of the A2 region 32, and the thickness t3 of the A3 region change, which changes the round-trip optical path length in the dielectric member 5 and changes the relative reflection phase of the electromagnetic wave. In conventional reflectarrays, the reflection direction of the electromagnetic wave is controlled by utilizing the property that the electromagnetic wave travels in the normal direction of an in-phase plane. The frequency selective reflector of this embodiment can also control the reflection direction of the electromagnetic wave in a similar manner. For example, in a frequency selective reflector having the reflection characteristics shown in FIG. 21( b), when a plane wave is incident from directly above the frequency selective reflector, the line (plane) connecting the center of the A1 region 31, the center of the A2 region 32, and the center of the A3 region 33 in that order can be considered as the in-phase plane of the reflected wave, and the reflected wave travels in the normal direction of that plane.

[0151] Therefore, as shown in FIG. 2, the incident electromagnetic wave W1 can be reflected in a direction different from the regular reflection (specular reflection) direction.

[0152] Therefore, according to the frequency selective reflector of this embodiment, for example, the A1 region in the dielectric member is an area that does not have the first dielectric pattern or the second dielectric pattern, the A2 region is an area that has only the first dielectric pattern, and the A3 region is an area that has the first dielectric pattern and the second dielectric pattern, and by changing the thickness of the A1 region, the thickness of the A2 region, and the thickness of the A3 region, the round-trip optical path length in the dielectric member can be changed in the A1 region, the A2 region, and the A3 region, and the reflection phase of the electromagnetic wave can be controlled. As a result, the reflection direction of the electromagnetic wave relative to a predetermined incident direction can be controlled to any direction.

[0153] Furthermore, in the present disclosure, the dielectric portions constituting each dielectric layer can be formed by various techniques, such as cutting, hollowing out processes such as laser processing, and 3D printing. Therefore, unlike the photolithography process for metal layers in conventional reflect arrays, a photomask is not required. Therefore, the desired dielectric portions can be formed relatively inexpensively and in a short period of time. In particular, when forming the dielectric portions by hollowing out processes such as cutting or laser processing, manufacturing costs and manufacturing time can be significantly reduced. Therefore, it is easy to meet the needs for small-lot, high-mix production. Furthermore, it becomes possible to use highly durable materials such as engineering plastics, which are not well suited for molding or 3D printing. Furthermore, when the dielectric member has only a first dielectric layer and a second dielectric layer as dielectric layers, the maximum thickness of the dielectric member can be reduced. Therefore, in the frequency selective reflector of this embodiment, by controlling the reflection phase of the electromagnetic wave depending on the thickness of each region of the dielectric member, a thin frequency selective reflector can be obtained, even while controlling the reflection direction of the electromagnetic wave.

[0154] Furthermore, in the frequency selective reflector of this embodiment, the thickness of each region of the dielectric member and the pitch of each region of the dielectric member affect the control of the reflection characteristics. The thickness of each region of the dielectric member and the pitch of each region of the dielectric member have a relatively wide processable range, so it is possible to increase, for example, the angle of incidence or reflection of the electromagnetic wave, thereby widening the control range of the reflection characteristics. Furthermore, the thickness of each region of the dielectric member and the pitch of each region of the dielectric member have a relatively wide margin of dimensional processing accuracy for achieving the desired reflection phase, so it is easy to obtain the desired reflection characteristics and the effects of dimensional variations can be reduced.

[0155] Furthermore, in the frequency selective reflector of this embodiment, the reflecting member may be a frequency selective plate that reflects only specific electromagnetic waves. Fig. 3 is a schematic plan view illustrating an example of a reflecting member, and is an example of the reflecting member shown in Fig. 18(a). As shown in Fig. 18(a) and Fig. 3, the reflecting member 2 has a plurality of ring-shaped reflecting elements 3 arranged on a dielectric substrate 4 and a plurality of reflecting elements 3 arranged on the surface of the dielectric substrate 4 opposite to the base material 21.

[0156] Furthermore, in the frequency selective reflector of this embodiment, the reflecting member may be a frequency selective plate that reflects only specific electromagnetic waves and has a reflection phase control function that controls the reflection phase of the electromagnetic waves. In such a reflecting member, by changing the dimensions and shape of the reflecting elements, the resonant frequency of each reflecting element can be changed and the reflection phase of the target electromagnetic wave can be controlled. In this case, the reflection phase of the electromagnetic wave can be controlled not only by the thickness of each region of the dielectric member but also by the dimensions and shape of the reflecting elements, thereby improving the design freedom in controlling the reflection characteristics.

[0157] Therefore, in the frequency selective reflector of this embodiment, when the above-mentioned reflective member is used, the degree of freedom in controlling the reflection characteristics can be increased by combining it with a dielectric member. For example, one example is to prepare multiple types of reflective members for the reflection characteristics in the vertical direction and combine them with a dielectric member that adjusts the reflection characteristics in the horizontal direction.

[0158] The inventors of the present disclosure also conducted a simulation of the reflection characteristics of electromagnetic waves in a specific frequency band in a frequency selective reflector having a reflecting member and a dielectric member according to the present disclosure, where the reflecting member is a frequency selective reflector having a reflecting element that reflects only specific electromagnetic waves. As a result, they found that the reflection phase shift at the reflecting element due to the proximity of the dielectric member to the reflecting member (frequency selective reflector) is greater than the reflection phase shift at the reflecting element due to the proximity of the dielectric member to the reflecting member (frequency selective reflector). They also found that the design of the actual reflection characteristics can be largely determined by designing the thickness of each region of the dielectric member. In this case, the resonant frequency of the reflecting element varies depending on whether or not there is a nearby dielectric member, but practical problems can be solved by designing the design assuming the presence of a dielectric member. Furthermore, they found that the in-plane arrangement of each region of the dielectric member to achieve the in-plane distribution design of the reflection phase in a frequency selective reflector does not need to be in a fixed positional relationship with the in-plane arrangement of the reflecting element of the reflecting member, and that even if each region of the dielectric member is shifted relative to the in-plane arrangement of the reflecting element, the reflection characteristics are not significantly affected.

[0159] Therefore, when combining a dielectric member and the above-described reflecting member in the frequency selective reflector of this embodiment, the dielectric member and the reflecting member can be designed independently and then combined. In this case, a dielectric member that achieves reflection characteristics according to the usage environment can be manufactured each time, or multiple specifications can be prepared in advance. This makes it easier to design the reflection direction of the frequency selective reflector that changes depending on the usage environment. As described above, when adjusting the overall reflection characteristics of the frequency selective reflector by combining the reflection phase distributions of the reflecting member and the dielectric member, precision in the misalignment of the reflecting member and the dielectric member is required according to the required specifications. On the other hand, when adjusting the reflection characteristics of the frequency selective reflector using only the reflection phase distribution of the dielectric member, precision in the misalignment of the reflecting member and the dielectric member is not required.

[0160] Furthermore, according to the frequency selective reflector of this embodiment, in the dielectric member, a plurality of first dielectric portions are arranged side by side in the first dielectric layer, and a plurality of second dielectric portions are arranged side by side in the second dielectric layer. In this way, the present disclosure utilizes tiling technology, making it possible to increase the area of ​​the frequency selective reflector.

[0161] However, as mentioned above, when using tiling technology for a frequency selective reflector, if the substrate strength is insufficient, the substrate may bend or flex due to the weight of the dielectric member and the reflecting member itself, which causes the dielectric member and the reflecting member to bend or flex as well, resulting in the problem that the desired reflection characteristics cannot be obtained.

[0162] For example, in a case where a first dielectric layer 111 and a second dielectric layer 112 are stacked in a dielectric member 105, such as the frequency selective reflector 100 shown in FIG. 22 , the first dielectric layer 111 is formed by arranging a plurality of first dielectric portions 111a side by side, and the second dielectric layer 112 is formed by arranging a plurality of second dielectric portions 112a side by side, it is conceivable to stack the first dielectric portions 111a and the second dielectric portions 112a so that their positions are aligned vertically. However, considering alignment accuracy, it is difficult to stack the first dielectric portions 111a and the second dielectric portions 112a so that the positions of the ends of the first dielectric portions 111a and the second dielectric portions 112a are aligned. Therefore, it is difficult to arrange the first dielectric portions 111a so that adjacent first dielectric portions 111a contact each other, or to arrange the second dielectric portions 112a so that adjacent second dielectric portions 112a contact each other. Therefore, because the ends of the dielectric parts on the top and bottom are not aligned, and therefore adjacent dielectric parts are separated, the substrate becomes more likely to bend or warp at the boundaries between adjacent dielectric parts.

[0163] In particular, in the dielectric member, the first dielectric portion constituting the first dielectric layer has a first dielectric pattern, the second dielectric portion constituting the second dielectric layer has a second dielectric pattern, and each dielectric portion has an opening, so the strength of each dielectric portion itself is relatively weak, which makes the above problem more pronounced.

[0164] In contrast, according to the present disclosure, in the dielectric member, the second dielectric portion is arranged so as to overlap the boundary between adjacent first dielectric portions in a planar view. This increases the strength of the entire dielectric member. Therefore, it is possible to suppress bending or flexing of the substrate at the boundary between adjacent first dielectric portions or the boundary between adjacent second dielectric portions. As a result, it is possible to suppress bending or flexing of each dielectric layer due to bending or flexing of the substrate. Therefore, it is possible to obtain desired reflection characteristics while increasing the area of ​​the frequency selective reflector. Furthermore, since it is not necessary to increase the thickness of the substrate in order to increase the strength of the substrate, it is also possible to reduce the weight and thickness of the frequency selective reflector.

[0165] Each configuration of the frequency selective reflector of this embodiment will be described below.

[0166] 1. Substrate The substrate in this embodiment is a member that supports the reflective member and the dielectric member.

[0167] (1) Substrate The substrate is not particularly limited as long as it can support the reflective member and the dielectric member, and examples thereof include a resin substrate. The resin substrate may be, for example, a resin film, a resin sheet, or a resin plate.

[0168] The substrate may be optically transparent or non-transparent. The optical properties of these substrates are appropriately selected depending on the detection method of the first alignment mark, the arrangement of the first alignment mark, etc., which will be described later. For example, when the first alignment mark is detected by transmitted light, the substrate is optically transparent. Furthermore, for example, when the first alignment mark is detected by reflected light, the substrate may be optically transparent or non-transparent. Furthermore, as will be described later, for example, when the first alignment mark is arranged on the surface of the substrate opposite to the reflective member and the dielectric member, the substrate is optically transparent.

[0169] In this specification, "light transmissive" means transmissive to visible light, and "light opaque" means opaque to visible light.

[0170] The substrate may be X-ray transparent. When the substrate is X-ray transparent, the first alignment mark is detected by transmitted X-rays.

[0171] The transmittance of the substrate is not particularly limited as long as the first alignment mark can be detected by transmitted light or reflected light, and can be set appropriately depending on the material, thickness, etc. of the substrate.

[0172] The resin constituting the resin substrate is not particularly limited, and examples thereof include engineering plastics.

[0173] Furthermore, the resin substrate may contain additives such as ultraviolet absorbers, light stabilizers, antioxidants, and colorants, as needed.

[0174] The thickness of the resin substrate is not particularly limited.

[0175] (2) First Alignment Mark The substrate preferably has an alignment mark. The alignment mark on the substrate can be used to align the multiple dielectric parts that make up each dielectric layer. For convenience, the alignment mark on the substrate is referred to as the first alignment mark. For example, in FIG. 23, the substrate 21 has a first alignment mark 22. In FIG. 23, the reflective member is omitted, and only the first dielectric layer of the dielectric member is shown.

[0176] The first alignment mark may be opaque. Alternatively, the first alignment mark may be reflective. These optical properties of the first alignment mark are appropriately selected depending on whether the first alignment mark is to be detected by transmitted light or reflected light. For example, when the first alignment mark is to be detected by transmitted light, the first alignment mark is opaque. Alternatively, when the first alignment mark is to be detected by reflected light, the first alignment mark is reflective.

[0177] In this specification, "light reflectivity" means reflectivity to visible light.

[0178] The first alignment mark may be X-ray transparent. When the substrate and the first alignment mark are X-ray transparent, the first alignment mark is detected by transmitted X-rays.

[0179] The transmittance and reflectance of the first alignment mark are not particularly limited as long as the first alignment mark can be detected by transmitted or reflected light, and can be set appropriately depending on the material, thickness, etc. of the first alignment mark.

[0180] The planar shape of the first alignment mark is not particularly limited and may be the same as the planar shape of a general alignment mark, and examples of the planar shape of the first alignment mark include a cross shape, an X shape, a square shape, a cross shape, a circle, a square shape, a triangle shape, a double circle shape, a double square shape, a circle with a hollow center, a square with a hollow center, and combinations thereof.

[0181] The size and line width of the first alignment mark are not particularly limited as long as the first alignment mark can be detected.

[0182] The number of first alignment marks is not particularly limited as long as it is possible to align the positions of the plurality of dielectric portions that make up each dielectric layer.

[0183] The position of the first alignment mark on the substrate is set appropriately according to the desired positions at which the plurality of dielectric portions constituting each dielectric layer are to be disposed.

[0184] The first alignment mark may be arranged on the surface of the substrate facing the reflective member and the dielectric member, or on the surface of the substrate opposite to the reflective member and the dielectric member.

[0185] The thickness of the first alignment mark is not particularly limited as long as it allows the first alignment mark to be formed with high precision, and is adjusted appropriately depending on the optical characteristics of the first alignment mark, etc.

[0186] Examples of materials for the first alignment mark include metal materials such as metals, alloys, metal oxides, and metal nitrides, and resins. In the case of resins, colorants can be added. Among these, resins are preferred in consideration of the influence of electromagnetic wave reflection by the first alignment mark.

[0187] The method for forming the first alignment mark is appropriately selected depending on the material of the first alignment mark, etc. In the case of a metal material, examples of the method for forming the first alignment mark include photolithography, mask vapor deposition, lift-off, and printing. In the case of a resin material, examples of the method for forming the first alignment mark include photolithography and printing.

[0188] (3) First Identification Mark In the present disclosure, the substrate may have an identification mark for identifying the positions of the plurality of dielectric portions constituting each dielectric layer. For convenience, the identification mark on the substrate is referred to as the first identification mark.

[0189] For example, in Figure 24, the substrate 21 has first identification marks 23 labeled "No. 1" and "No. 2." In Figure 24, the reflective member is omitted and only the first dielectric layer of the dielectric member is shown. By having the first identification marks on the substrate, the positions of the multiple dielectric portions constituting each dielectric layer can be easily identified, so that the multiple dielectric portions constituting each dielectric layer can be reliably and easily positioned in the correct positions. This is particularly useful when the dielectric member has multiple reflective regions with different reflective characteristics, as will be described later.

[0190] The first identification mark may be opaque or reflective, and the optical properties of the first identification mark are appropriately selected depending on whether the first identification mark is to be detected by transmitted light or reflected light, as with the first alignment mark.

[0191] The transmittance and reflectance of the first identification mark are not particularly limited as long as the first identification mark can be detected by transmitted light or reflected light, and can be set appropriately depending on the material, thickness, etc. of the first identification mark.

[0192] The first identification mark is not particularly limited as long as it is an identifiable mark, and examples thereof include letters, symbols, figures, etc. Specific examples include codes. The first identification mark may also be data that can be recognized by optical character recognition (OCR).

[0193] The size and line width of the first identification mark are not particularly limited as long as the first identification mark can be detected.

[0194] The position of the first identification mark on the substrate is not particularly limited as long as it allows identification of the positions of the plurality of dielectric portions that make up each dielectric layer.

[0195] The first identification mark may be disposed on the surface of the substrate facing the reflective member and the dielectric member, or on the surface of the substrate opposite to the reflective member and the dielectric member.

[0196] The thickness, material, and formation method of the first identification mark are the same as those of the first alignment mark.

[0197] If the material of the first identification mark is the same as the material of the first alignment mark, the first alignment mark and the first identification mark can be formed simultaneously.

[0198] 2. Dielectric Member The dielectric member in this embodiment is a member that is disposed on the surface of the reflecting member opposite the substrate and transmits electromagnetic waves in a specific frequency band. The dielectric member is disposed on the electromagnetic wave incident side of the reflecting member. The dielectric member also has, in this order from the reflecting member side, a first dielectric layer and a second dielectric layer. The first dielectric layer has a plurality of first dielectric portions disposed on the surface of the reflecting member opposite the substrate, and the second dielectric layer has a plurality of second dielectric portions disposed on the surface of the first dielectric layer opposite the reflecting member.

[0199] (1) Arrangement of Dielectric Portions In the dielectric member of this embodiment, the second dielectric portions are arranged so as to overlap the boundaries of adjacent first dielectric portions in a plan view.

[0200] The "boundary between adjacent first dielectric portions" refers to the boundary between an end of one first dielectric portion and an end of the other first dielectric portion in two adjacent first dielectric portions. The end of a first dielectric portion refers to the most protruding part on the side surface of the first dielectric portion.

[0201] 25(a) to 25(d) show examples of the end portions 11E of the first dielectric portions 11a and 11b and the boundary 11X between adjacent first dielectric portions 11a and 11b. Fig. 25(a) shows an example in which the side surfaces of the first dielectric portions 11a and 11b are vertical. Figs. 25(b) and 25(c) show examples in which the side surfaces of the first dielectric portions 11a and 11b are inclined. Fig. 25(d) shows an example in which the side surfaces of the first dielectric portions 11a and 11b are curved.

[0202] Furthermore, "the second dielectric portion is arranged so as to overlap the boundary between the adjacent first dielectric portions in a plan view" means that the second dielectric portion is arranged so as to overlap at least a portion of the boundary between the adjacent first dielectric portions in a plan view. That is, there may be a portion of the boundary between the adjacent first dielectric portions that is not overlapped by the second dielectric portion in a plan view.

[0203] 18 and 26 to 30 show examples of the arrangement of the first dielectric portion and the second dielectric portion. In FIG. 18(a), the first dielectric layer 11 has two first dielectric portions 11a and 11b, and the second dielectric layer 12 has three second dielectric portions 12a, 12b, and 12c, with the second dielectric portion 12b being arranged to overlap the entire boundary 11X between adjacent first dielectric portions 11a and 11b in a planar view. In FIGS. 26(a) to 26(c), the first dielectric layer 11 has two first dielectric portions 11a and 11b, and the second dielectric layer 12 has two second dielectric portions 12a and 12b, with each second dielectric portion 12a and 12b being arranged to overlap a portion of the boundary 11X between adjacent first dielectric portions 11a and 11b in a planar view. 27(a) to 27(c), the first dielectric layer 11 has four first dielectric portions 11a to 11d, the second dielectric layer 12 has seven second dielectric portions 12a to 12g, and in a planar view, the second dielectric portion 12c is arranged so as to overlap a portion of the boundary 11X between the adjacent first dielectric portions 11a and 11b, the second dielectric portion 12f is arranged so as to overlap a portion of the boundary 11X between the adjacent first dielectric portions 11c and 11d, and the second dielectric portion 12a is arranged so as to overlap a portion of the boundary 11X between the adjacent first dielectric portions 11a and 11b, a portion of the boundary 11X between the adjacent first dielectric portions 11c and 11d, a portion of the boundary 11X between the adjacent first dielectric portions 11a and 11c, and a portion of the boundary 11X between the adjacent first dielectric portions 11b and 11d. In Figures 28(a) to (c), the first dielectric layer 11 has four first dielectric portions 11a to 11d, and the second dielectric layer 12 has four second dielectric portions 12a to 12d, and in a planar view, the second dielectric portion 12a is arranged so as to overlap a portion of the boundary 11X between adjacent first dielectric portions 11a and 11b, the second dielectric portion 12d is arranged so as to overlap a portion of the boundary 11X between adjacent first dielectric portions 11b and 11d, and the second dielectric portion 12c is arranged so as to overlap a portion of the boundary 11X between adjacent first dielectric portions 11a and 11b, the entire boundary 11X between adjacent first dielectric portions 11c and 11d, the entire boundary 11X between adjacent first dielectric portions 11a and 11c, and a portion of the boundary 11X between adjacent first dielectric portions 11b and 11d.29(a) to 29(c), the first dielectric layer 11 has four first dielectric portions 11a to 11d, the second dielectric layer 12 has seven second dielectric portions 12a to 12g, and in plan view, the second dielectric portion 12b is arranged so as to overlap a portion of the boundary 11X between adjacent first dielectric portions 11a and 11b, the second dielectric portion 12f is arranged so as to overlap a portion of the boundary 11X between adjacent first dielectric portions 11c and 11d, and the second dielectric portion 12d is arranged so as to overlap a portion of the boundary 11X between adjacent first dielectric portions 11a and 11b, a portion of the boundary 11X between adjacent first dielectric portions 11c and 11d, the entire boundary 11X between adjacent first dielectric portions 11a and 11c, and the entire boundary 11X between adjacent first dielectric portions 11b and 11d. In Figures 30(a) to (c), the first dielectric layer 11 has two first dielectric portions 11a and 11b, and the second dielectric layer 12 has two second dielectric portions 12a and 12b, and the second dielectric portions 12a and 12b are each arranged so as to overlap a portion of the boundary 11X between adjacent first dielectric portions 11a and 11b in a planar view.

[0204] In the entire dielectric component, the second dielectric portion is arranged so as to overlap a portion of the boundary between adjacent first dielectric portions in a plan view. In particular, it is preferable that the second dielectric portion is arranged so as to overlap the entire boundary between adjacent first dielectric portions in a plan view. That is, it is preferable that the entire boundary between adjacent first dielectric portions is covered by the second dielectric portion in a plan view. By arranging the second dielectric portion so as to overlap a portion of the boundary between adjacent first dielectric portions in a plan view, the strength of the entire dielectric component can be increased. Furthermore, the second dielectric portion may be arranged so as to overlap 1 / 10 or more of the total area of ​​the boundaries between adjacent first dielectric portions in a plan view. In this case, it is preferable that the second dielectric portion is arranged so as to overlap 1 / 5 or more of the total area of ​​the boundaries between adjacent first dielectric portions in a plan view.

[0205] Furthermore, as will be described later, when the dielectric member has a first dielectric layer, a second dielectric layer, and a third dielectric layer, the arrangement of the third dielectric portion constituting the third dielectric layer is not particularly limited.

[0206] In particular, it is preferable that the third dielectric portion be arranged so as to overlap the boundary between the adjacent dielectric portions in a plan view with respect to the dielectric portion constituting the dielectric layer adjacent to the third dielectric layer. For example, as shown in Figures 31(a) and 31(b), when the first dielectric layer 11, the second dielectric layer 12, and the third dielectric layer 13 are arranged in this order from the reflecting member 2 side, it is preferable that the third dielectric portions 13a, 13b, and 13c are arranged so as to overlap the boundary 12X between the adjacent second dielectric portions 12a and 12b and the boundary 12X between the adjacent second dielectric portions 12b and 12c in a plan view. Furthermore, when the third dielectric layer, the first dielectric layer, and the second dielectric layer are arranged in this order from the reflecting member side, it is preferable that the third dielectric portion be arranged so as to overlap the boundary between the adjacent first dielectric portions in a plan view. Furthermore, when the first dielectric layer, the third dielectric layer, and the second dielectric layer are arranged in this order from the reflective member side, it is preferable that the third dielectric portion be arranged so as to overlap the boundary between adjacent first dielectric portions and so as to overlap the boundary between adjacent second dielectric portions in a plan view, which can further increase the strength of the entire dielectric member.

[0207] In particular, regardless of the position of the third dielectric layer, it is preferable that the third dielectric portion be arranged so as to overlap the boundary between adjacent first dielectric portions and the boundary between adjacent second dielectric portions in a plan view. This can further increase the strength of the dielectric member. For example, in Figure 31(b), the third dielectric portions 13a to 13c are arranged so as to overlap the boundary 11X between adjacent first dielectric portions and the boundary 12X between adjacent second dielectric portions in a plan view.

[0208] The "boundary between adjacent second dielectric portions" is the same as the explanation for the "boundary between adjacent first dielectric portions" above. Also, the "third dielectric portion is arranged so as to overlap the boundary between adjacent first dielectric portions in a plan view" and "the third dielectric portion is arranged so as to overlap the boundary between adjacent second dielectric portions in a plan view" are the same as the explanation for the "second dielectric portion is arranged so as to overlap the boundary between adjacent first dielectric portions in a plan view" above.

[0209] Furthermore, as will be described later, when the dielectric member has three or more dielectric layers, the arrangement of the dielectric portions constituting the dielectric layers other than the first and second dielectric layers is not particularly limited. The arrangement of the dielectric portions constituting the dielectric layers other than the first and second dielectric layers is the same as the arrangement of the third dielectric portion constituting the third dielectric layer described above.

[0210] In plan view, the distance between the boundary between adjacent first dielectric portions and the boundary between adjacent second dielectric portions is preferably greater than the alignment accuracy caused by an alignment device or the like.

[0211] In addition, in a plan view, the distance between the boundary between adjacent first dielectric portions and the boundary between adjacent second dielectric portions is preferably at least one-third of the thickness of the dielectric member. By setting this distance within the above range, the bending strength can be increased.

[0212] The "distance between the boundary between adjacent first dielectric portions and the boundary between adjacent second dielectric portions" refers to the distance between the boundary between adjacent first dielectric portions, the second dielectric portion located on the boundary between the first dielectric portions, and the boundary between the second dielectric portion adjacent to the second dielectric portion. For example, in Figure 32(a), the distance between the boundary 11X between adjacent first dielectric portions 11a and 11b, the distance between the second dielectric portion 12b located on the boundary 11X between the first dielectric portions 11a and 11b, and the distance between the boundary 12X between the second dielectric portions 12a and 12c adjacent to the second dielectric portion 12b. １ , 12X ２ The distances d1 and d2 between the boundary of the adjacent first dielectric portion and the boundary of the adjacent second dielectric portion are the distances between the boundaries of the adjacent first dielectric portion and the adjacent second dielectric portion. Furthermore, the "distance between the boundary of the adjacent first dielectric portion and the boundary of the adjacent second dielectric portion" refers to the distance from the center of the boundary of the adjacent first dielectric portion to the center of the boundary of the adjacent second dielectric portion.

[0213] Furthermore, as will be described later, when the dielectric member has three or more dielectric layers, in two adjacent dielectric layers, the distance between the boundary of adjacent dielectric portions in the lower dielectric layer and the boundary of adjacent dielectric portions in the upper dielectric layer is the same as the distance between the boundary of adjacent first dielectric portions and the boundary of adjacent second dielectric portions described above.

[0214] In the first dielectric layer, the distance between adjacent first dielectric portions is preferably less than 1 / 2 of the wavelength of electromagnetic waves in a specific frequency band, more preferably 1 / 5 or less, and even more preferably 1 / 10 or less.

[0215] Although not a reflectarray, in a phased array antenna in which multiple subarrays are arranged side by side, the distance between adjacent subarrays is usually set to less than 1 / 2 the wavelength of the electromagnetic wave in order to align the phase of the electromagnetic wave in each subarray and increase the intensity of the electromagnetic wave. In the present disclosure, since multiple dielectric portions are arranged side by side in each dielectric layer, it is considered desirable for the distance between adjacent dielectric portions to be less than 1 / 2 the wavelength of the electromagnetic wave in order to suppress disturbance of the wavefront of the reflected wave in the entire frequency selective reflector, for example, by aligning the phase of the reflected wave in each dielectric portion and increasing the intensity of the reflected wave.

[0216] As will be described later, the frequency band of the electromagnetic waves is preferably 24 GHz or higher, i.e., the wavelength of the electromagnetic waves in air is preferably 12.49 mm or shorter. Therefore, the distance between adjacent first dielectric portions is specifically 6.245 mm or shorter. Furthermore, the shorter the distance between adjacent first dielectric portions, the better, and there is no particular limit to the lower limit.

[0217] The "distance between adjacent first dielectric portions" refers to the distance between the end of one first dielectric portion and the end of the other first dielectric portion in two adjacent first dielectric portions. For example, in Figures 25(a) to 25(d), the distance d11 between the end 11E of the first dielectric portion 11a and the end 11E of the first dielectric portion 11b is the distance between the adjacent first dielectric portions 11a and 11b.

[0218] In the second dielectric layer, the distance between adjacent second dielectric portions is the same as the distance between adjacent first dielectric portions described above.

[0219] Furthermore, as described below, when the dielectric member has a first dielectric layer, a second dielectric layer, and a third dielectric layer, the distance between adjacent third dielectric portions in the third dielectric layer is the same as the distance between adjacent first dielectric portions described above.

[0220] Furthermore, as described below, when the dielectric member has three or more dielectric layers, the distance between adjacent dielectric portions in the dielectric layers other than the first dielectric layer and the second dielectric layer is the same as the distance between adjacent first dielectric portions described above.

[0221] (2) Number of Dielectric Portions The first dielectric layer has a plurality of first dielectric portions arranged side by side on the surface of the reflecting member opposite the substrate. The number of first dielectric portions in the first dielectric layer may be two or more and is appropriately selected depending on the size of the frequency selective reflector and the size of the first dielectric portions. There is no particular upper limit on the number of first dielectric portions.

[0222] The second dielectric layer has a plurality of second dielectric portions arranged side by side on the surface of the first dielectric layer opposite the reflecting member. The number of second dielectric portions in the second dielectric layer may be two or more and is appropriately selected depending on the size of the frequency selective reflector and the size of the second dielectric portions. There is no particular upper limit on the number of second dielectric portions. The number of second dielectric portions may be the same as or different from the number of first dielectric portions. When the number of first dielectric portions and the number of second dielectric portions are different, the number of second dielectric portions may be less than or greater than the number of first dielectric portions. When the number of second dielectric portions is greater than the number of first dielectric portions, the strength of the second dielectric portions can be increased as described below. When the number of second dielectric portions is greater than the number of first dielectric portions, the average size of the second dielectric portions is smaller than the size of the first dielectric portions. Therefore, the strength of the second dielectric portions can be increased, thereby increasing the strength of the second dielectric layer. On the other hand, in order to arrange the second dielectric portion so that it overlaps the boundary between adjacent first dielectric portions in a planar view, the sizes of the first dielectric portion and the second dielectric portion may be adjusted so that the number of second dielectric portions is equal to or less than the number of first dielectric portions.

[0223] Furthermore, as described below, when the dielectric member has a first dielectric layer, a second dielectric layer, and a third dielectric layer, a plurality of third dielectric portions are arranged side by side in the third dielectric layer. In the third dielectric layer, the number of third dielectric portions may be two or more, and is appropriately selected depending on the size of the frequency selective reflector and the size of the third dielectric portion. The upper limit of the number of third dielectric portions is not particularly limited. The number of third dielectric portions may be the same as or different from the number of first dielectric portions. When the number of first dielectric portions and the number of third dielectric portions are different, the number of third dielectric portions may be less than or greater than the number of first dielectric portions. Furthermore, the number of third dielectric portions may be the same as or different from the number of second dielectric portions. When the number of second dielectric portions and the number of third dielectric portions are different, the number of third dielectric portions may be less than or greater than the number of second dielectric portions.

[0224] When the first, second, and third dielectric layers are arranged in this order from the reflecting member side, there are, for example, the following five combinations of the numbers of first, second, and third dielectric portions: a first combination in which the number of second dielectric portions is different from the number of first and third dielectric portions and the number of first and third dielectric portions is the same; a second combination in which the number of second dielectric portions is different from the number of first dielectric portions and the number of second dielectric portions is the same as the number of third dielectric portions; a third combination in which the number of second dielectric portions is the same as the number of first dielectric portions and the number of second dielectric portions is different from the number of third dielectric portions; a fourth combination in which the numbers of first, second, and third dielectric portions are different from one another; and a fifth combination in which the numbers of first, second, and third dielectric portions are the same. In any of the combinations, when the number of dielectric portions constituting a dielectric layer is greater than the number of dielectric portions constituting an adjacent dielectric layer, the strength of the dielectric layer with a greater number of dielectric portions can be increased as shown below. A dielectric layer having a large number of dielectric portions has a smaller average size of the dielectric portions than a dielectric layer having a small number of dielectric portions, and therefore the strength of the dielectric portions in the dielectric layer having a large number of dielectric portions can be increased, thereby increasing the strength of the dielectric layer having a large number of dielectric portions.

[0225] When the third dielectric layer, the first dielectric layer, and the second dielectric layer are arranged in order from the reflecting member side, and when the first dielectric layer, the third dielectric layer, and the second dielectric layer are arranged in order from the reflecting member side, the number of first dielectric portions, the number of second dielectric portions, and the number of third dielectric portions can be considered to be the same as the number of first dielectric portions, the number of second dielectric portions, and the number of third dielectric portions when the first dielectric layer, the second dielectric layer, and the third dielectric layer are arranged in order from the reflecting member side.

[0226] Furthermore, as will be described later, when the dielectric member has three or more dielectric layers, the number of dielectric portions in the dielectric layers other than the first dielectric layer and the second dielectric layer is the same as the number of the third dielectric portions described above.

[0227] (3) Size and Shape of Dielectric Layer and Dielectric Portion The size of each dielectric layer refers to the outer size of each dielectric layer in a planar view. Specifically, the outer size of the dielectric layer in a planar view refers to the size of the area surrounded by the outermost contour of the dielectric layer when the dielectric layer is viewed in a planar view. Furthermore, the size of each dielectric portion refers to the outer size of each dielectric portion when viewed in a planar view. Specifically, the outer size of the dielectric portion in a planar view refers to the size of the area surrounded by the outermost contour of the dielectric portion when the dielectric portion is viewed in a planar view. Furthermore, the shape of each dielectric portion when viewed in a planar view refers to the outer shape of each dielectric portion when viewed in a planar view. For example, in Figures 19(a) and 20(a), support portions are present at the outermost periphery of each dielectric portion, but support portions are not necessarily present at the outermost periphery of each dielectric portion. In such a case, the area surrounded by the outermost contour line of the dielectric portion when viewed in a plane is the area surrounded by the outermost contour line of the area combining the dielectric pattern and the opening, for example, in Figure 19(a) it is a rectangular area that includes the diagonal line portion of the dielectric pattern, and the external size of the dielectric portion when viewed in a plane is the size of the rectangular area.

[0228] In the first dielectric layer, the size of the first dielectric portion is appropriately selected depending on the size of the substrate, the application of the frequency selective reflector, etc. The size of the first dielectric portion is, for example, preferably 150 mm square or more, and more preferably 200 mm square or more. The sizes of the multiple first dielectric portions may be the same or different. When the multiple first dielectric portions have the same size, the first dielectric portions are easy to manufacture, store, transport, etc. For example, Figure 18 and Figures 26 to 30 show examples in which the multiple first dielectric portions have the same size.

[0229] The size of the second dielectric portion in the second dielectric layer is the same as the size of the first dielectric portion described above. The size of the second dielectric portion may be the same as or different from the size of the first dielectric portion. When the sizes of the first dielectric portion and the second dielectric portion are different, the size of the second dielectric portion may be smaller or larger than the size of the first dielectric portion. When the size of the second dielectric portion is equal to or smaller than the size of the first dielectric portion, the strength of the second dielectric portion can be increased as described above. On the other hand, in order to arrange the second dielectric portion so that it overlaps the boundary between adjacent first dielectric portions in a planar view, the sizes of the first and second dielectric portions may be adjusted so that the size of the second dielectric portion is equal to or smaller than the size of the first dielectric portion. Furthermore, when the size of the second dielectric portion is an integer multiple or an integer fraction of the size of the first dielectric portion, the manufacturing, storage, transportation, etc. of the first and second dielectric portions are easy. For example, in FIG. 18, the second dielectric portions 12a and 12c are approximately half the size of the first dielectric portions 11a and 12b. For example, in Figure 27, the second dielectrics 12b to 12g are approximately half the size of the first dielectrics 11a to 11d. The sizes of the multiple second dielectric portions may be the same or different. If the multiple second dielectric portions are the same size, the second dielectric portions are easy to manufacture, store, transport, etc. For example, Figures 26 and 30 are examples in which the multiple second dielectric portions are the same size. Also, for example, Figures 18 and 27 to 29 are examples in which the multiple second dielectric portions are not all the same size.

[0230] Furthermore, as described below, when the dielectric member has a first dielectric layer, a second dielectric layer, and a third dielectric layer, the size of the third dielectric portion in the third dielectric layer is the same as the size of the first dielectric portion described above. The size of the third dielectric portion may be the same as or different from the size of the first dielectric portion. When the sizes of the first dielectric portion and the third dielectric portion are different, the size of the third dielectric portion may be smaller or larger than the size of the first dielectric portion. Furthermore, the size of the third dielectric portion may be the same as or different from the size of the second dielectric portion. When the sizes of the second dielectric portion and the third dielectric portion are different, the size of the third dielectric portion may be smaller or larger than the size of the second dielectric portion.

[0231] When the first, second, and third dielectric layers are arranged in this order from the reflecting member side, there are, for example, the following five combinations of sizes for the first, second, and third dielectric portions: a first combination in which the size of the second dielectric portion is different from the sizes of the first and third dielectric portions and the size of the first and third dielectric portions is the same; a second combination in which the size of the second dielectric portion is different from the size of the first dielectric portion and the same as the size of the third dielectric portion; a third combination in which the size of the second dielectric portion is the same as the size of the first dielectric portion and different from the size of the third dielectric portion; a fourth combination in which the sizes of the first, second, and third dielectric portions are different from one another; and a fifth combination in which the sizes of the first, second, and third dielectric portions are the same. In any combination, if the size of the dielectric portion constituting a dielectric layer is smaller than the size of the dielectric portion constituting the adjacent dielectric layer, for the reasons described above, the strength of the dielectric portion in the dielectric layer having the smaller size can be increased, thereby also increasing the strength of the dielectric layer.

[0232] When the third dielectric layer, the first dielectric layer, and the second dielectric layer are arranged in order from the reflecting member side, and when the first dielectric layer, the third dielectric layer, and the second dielectric layer are arranged in order from the reflecting member side, the sizes of the first dielectric portion, the second dielectric portion, and the third dielectric portion can be considered to be similar to the sizes of the first dielectric portion, the second dielectric portion, and the third dielectric portion when the first dielectric layer, the second dielectric layer, and the third dielectric layer are arranged in order from the reflecting member side.

[0233] Furthermore, when the size of the third dielectric portion is an integer multiple or an integer fraction of the size of the first dielectric portion and an integer multiple or an integer fraction of the size of the second dielectric portion, the first dielectric portion, the second dielectric portion, and the third dielectric portion are easy to manufacture, store, transport, etc. The sizes of the multiple third dielectric portions may be the same or different. When the sizes of the multiple third dielectric portions are the same, the third dielectric portions are easy to manufacture, store, transport, etc.

[0234] Furthermore, as will be described later, when the dielectric member has three or more dielectric layers, the size of the dielectric portion in the dielectric layers other than the first dielectric layer and the second dielectric layer is the same as the size of the third dielectric portion described above.

[0235] The sizes of the first dielectric layer and the second dielectric layer are appropriately selected depending on the size of the substrate, the application of the frequency selective reflector, etc. The sizes of the first dielectric layer and the second dielectric layer are usually the same.

[0236] Also, as described below, when the dielectric member has a first dielectric layer, a second dielectric layer, and a third dielectric layer, the size of the third dielectric layer is usually the same as the size of the first dielectric layer and the size of the second dielectric layer.

[0237] Furthermore, as will be described later, when the dielectric member has three or more dielectric layers, the sizes of the dielectric layers other than the first dielectric layer and the second dielectric layer are typically the same as the sizes of the first dielectric layer and the second dielectric layer.

[0238] The planar shape of the first dielectric portions is not particularly limited as long as it allows the first dielectric portions to be arranged without gaps, and examples include squares and rectangles. The planar shapes of the multiple first dielectric portions may be the same or different. When the multiple first dielectric portions have the same planar shape, the first dielectric portions are easily manufactured, stored, transported, and the like. For example, Figure 18 and Figures 26 to 30 show examples in which the planar shape of the first dielectric portions is square or rectangular, and the planar shapes of the multiple first dielectric portions are the same.

[0239] The planar shape of the second dielectric portions is not particularly limited as long as it allows the second dielectric portions to be arranged without gaps, and is appropriately selected depending on the arrangement of the first dielectric portions. Examples include squares, rectangles, and right-angled triangles. The planar shapes of multiple second dielectric portions may be the same or different. When multiple second dielectric portions have the same planar shape, the second dielectric portions are easily manufactured, stored, transported, and the like. For example, Figures 18 and 26 to 29 show examples in which the planar shape of the second dielectric portions is square or rectangular, and of these, Figure 26 shows an example in which multiple second dielectric portions have the same planar shape. For example, Figure 30 shows an example in which the planar shape of the second dielectric portions is a right-angled triangle and multiple second dielectric portions have the same planar shape.

[0240] Furthermore, as will be described later, when the dielectric member has three or more dielectric layers, the planar shapes of the dielectric portions in the dielectric layers other than the first dielectric layer and the second dielectric layer are the same as the planar shapes of the first dielectric portion and the second dielectric portion described above.

[0241] (4) Number of Stacked Dielectric Layers In the present disclosure, the dielectric member has a first dielectric layer and a second dielectric layer in this order from the reflecting member side.

[0242] The dielectric member may have at least a first dielectric layer and a second dielectric layer, for example, the dielectric member may have a first dielectric layer, a second dielectric layer, and a third dielectric layer. The position of the third dielectric layer is not particularly limited, and the first dielectric layer, the second dielectric layer, and the third dielectric layer may be arranged in this order from the reflecting member side, the third dielectric layer, the first dielectric layer, and the second dielectric layer may be arranged in this order from the reflecting member side, or the first dielectric layer, the third dielectric layer, and the second dielectric layer may be arranged in this order from the reflecting member side.

[0243] Furthermore, the dielectric member may have at least two dielectric layers, a first dielectric layer and a second dielectric layer, and may have, for example, three or more dielectric layers. The number of laminated dielectric layers may be two or more, and may be three or more. The greater the number of laminated dielectric layers, the higher the reflection intensity of electromagnetic waves in the entire frequency selective reflector. Furthermore, the greater the number of laminated dielectric layers, the more the stress in the bending direction can be dispersed, and the greater the bending strength of the dielectric member. The upper limit of the number of laminated dielectric layers is not particularly limited, but is, for example, 10 or less. If the number of laminated dielectric layers is too large, the thickness of each dielectric layer will be thin, which may make it difficult to manufacture the dielectric section that constitutes the dielectric layer or may significantly reduce the strength of the dielectric section itself.

[0244] When the dielectric section has three or more dielectric layers, the positions of the dielectric layers other than the first and second dielectric layers are the same as the position of the third dielectric layer described above.

[0245] (5) Regions of the Dielectric Member When the dielectric member has a first dielectric layer and a second dielectric layer as the dielectric layers, for example, as shown in Figure 21 (a), the dielectric member 5 has, from the reflecting member 2 side, an A1 region 31 that does not have the first dielectric pattern 11P or the second dielectric pattern 12P, an A2 region 32 that has only the first dielectric pattern 11P from the reflecting member 2 side, and an A3 region 33 that has the first dielectric pattern 11P and the second dielectric pattern 12P from the reflecting member 2 side.

[0246] The absolute value of the difference between the relative reflection phase of the electromagnetic wave in the A1 region and the relative reflection phase of the electromagnetic wave in the A2 region, and the absolute value of the difference between the relative reflection phase of the electromagnetic wave in the A2 region and the relative reflection phase of the electromagnetic wave in the A3 region are determined based on a simulation taking into account reflection loss. If the simulation determines that the absolute value of the difference between the relative reflection phases of the electromagnetic waves is optimal to be 120 degrees, the absolute value of the difference between the relative reflection phases of the electromagnetic waves is, for example, preferably 90 degrees or more and 150 degrees or less, more preferably 110 degrees or more and 130 degrees or less, and even more preferably 115 degrees or more and 125 degrees or less. In such cases, disturbance of the wavefront of the reflected wave can be suppressed.

[0247] In the above case, in the dielectric member, the difference between the round-trip optical path length in the A1 region and the round-trip optical path length in the A2 region is designed so that the absolute value of the difference between the relative reflection phase of the electromagnetic wave in the A1 region and the relative reflection phase of the electromagnetic wave in the A2 region is set as described above. Similarly, the difference between the round-trip optical path length in the A2 region and the round-trip optical path length in the A3 region is designed so that the absolute value of the difference between the relative reflection phase of the electromagnetic wave in the A2 region and the relative reflection phase of the electromagnetic wave in the A3 region is set as described above. Furthermore, the thickness of the A1 region is 0, and the thickness of the A2 region is set so that the difference between the thickness of the A1 region and the thickness of the A2 region is the difference between the round-trip optical path length in the A1 region and the round-trip optical path length in the A2 region. In other words, the thickness of the first dielectric layer is set so that the difference between the round-trip optical path length in the A1 region and the round-trip optical path length in the A2 region. Similarly, the thickness of the A3 region is set so that the difference between the thickness of the A2 region and the thickness of the A3 region is the difference between the round-trip optical path length in the A2 region and the round-trip optical path length in the A3 region. That is, the thickness of the second dielectric layer is set to be the difference between the round-trip optical path length in the A2 region and the round-trip optical path length in the A3 region.

[0248] The thickness of the A1 region is 0. The thickness of the A2 region and the thickness of the A3 region are each set appropriately depending on the wavelength of the electromagnetic wave, the dielectric constant of the material of each dielectric layer, and the desired reflection characteristics. For example, if the effective wavelength of the electromagnetic wave passing through the dielectric is λ ｇ In this case, the thickness of the A2 region and the thickness of the A3 region are each greater than 0, and λ ｇ Specifically, the wavelength λ of the electromagnetic wave in the air is preferably 1 / 2 or less. ０When the dielectric constant of each dielectric layer is 2.57 and the thickness of the A2 region and the thickness of the A3 region are each preferably greater than 0 mm and equal to or less than 8.6 mm.

[0249] The effective wavelength of an electromagnetic wave refers to the wavelength when the electromagnetic wave passes through a material other than air, such as a dielectric layer. When simply referring to the wavelength, it refers to the wavelength in air.

[0250] When the dielectric member has a first dielectric layer, a second dielectric layer, and a third dielectric layer as the dielectric layers, the third dielectric layer has a third dielectric pattern, similar to the first and second dielectric layers, and in this case, the dielectric member has four regions.

[0251] When the dielectric member has a first dielectric layer, a second dielectric layer, and a third dielectric layer in this order from the reflecting member side, as shown in, for example, Figure 33 (a), the dielectric member 5 has, from the reflecting member 2 side, a B1 region 41 which does not have the first dielectric pattern 11P, the second dielectric pattern 12P, and the third dielectric pattern 13P, a B2 region 42 which has only the first dielectric pattern 11P from the reflecting member 2 side, a B3 region 43 which has only the first dielectric pattern 11P and the second dielectric pattern 12P from the reflecting member 2 side, and a B4 region 44 which has the first dielectric pattern 11P, the second dielectric pattern 12P, and the third dielectric pattern 13P from the reflecting member 2 side.

[0252] Fig. 33(b) shows an example of the relative reflection phases of electromagnetic waves in the B1, B2, B3, and B4 regions of the dielectric member 5 in the frequency selective reflector shown in Fig. 33(a). As shown in Fig. 33(b), when the absolute value of the difference in relative reflection phases with small reflection loss is 90 degrees, the relative reflection phases of electromagnetic waves in the B1 region 41, B2 region 42, B3 region 43, and B4 region 44 of the dielectric member 5 are 0 degrees (-360 degrees), -90 degrees, -180 degrees, and -270 degrees, respectively.

[0253] In the above case, as shown in Figure 33(a), the thickness t11 of the B1 region 41 is 0, and the thickness t11 of the B1 region 41, the thickness t12 of the B2 region 42, the thickness t13 of the B3 region 43, and the thickness t14 of the B4 region 44 are all different from one another. Therefore, the round-trip optical path length in the dielectric member is changed in the B1 region, the B2 region, the B3 region, and the B4 region, and the reflection phase of the electromagnetic wave can be controlled. This allows the reflection direction of the electromagnetic wave relative to a predetermined incident direction to be controlled to any direction.

[0254] The absolute value of the difference between the relative reflection phase of the electromagnetic wave in the B1 region and the relative reflection phase of the electromagnetic wave in the B2 region, the absolute value of the difference between the relative reflection phase of the electromagnetic wave in the B2 region and the relative reflection phase of the electromagnetic wave in the B3 region, and the absolute value of the difference between the relative reflection phase of the electromagnetic wave in the B3 region and the relative reflection phase of the electromagnetic wave in the B4 region are determined based on a simulation taking into account reflection loss. If the simulation determines that the absolute value of the difference between the relative reflection phases of the electromagnetic waves is optimal to be 90 degrees, the absolute value of the difference between the relative reflection phases of the electromagnetic waves is, for example, preferably 60 degrees or more and 120 degrees or less, more preferably 80 degrees or more and 100 degrees or less, and even more preferably 85 degrees or more and 95 degrees or less. In such cases, the wavefront disturbance of the reflected wave can be suppressed.

[0255] In the above case, in the dielectric member, the difference in the round-trip optical path length between adjacent regions B1, B2, B3, and B4 is designed so that the absolute value of the difference between the relative reflection phase of the electromagnetic wave in the adjacent regions is set as described above. Furthermore, the thickness of region B1 is 0, and the thickness of region B2 is set so that the difference between the thickness of region B1 and the thickness of region B2 is the difference between the round-trip optical path length in region B1 and the round-trip optical path length in the two regions. That is, the thickness of the first dielectric layer is set so that the difference between the round-trip optical path length in region B1 and the round-trip optical path length in region B2. Similarly, the thickness of region B3 is set so that the difference between the thickness of region B2 and the thickness of region B3 is the difference between the round-trip optical path length in region B2 and the round-trip optical path length in region B3. That is, the thickness of the second dielectric layer is set so that the difference between the round-trip optical path length in region B2 and the round-trip optical path length in region B3. Similarly, the thickness of the B4 region is set so that the difference between the thickness of the B3 region and the thickness of the B4 region is equal to the difference between the round-trip optical path length in the B3 region and the round-trip optical path length in the B4 region. In other words, the thickness of the third dielectric layer is set so as to be equal to the difference between the round-trip optical path length in the B3 region and the round-trip optical path length in the B4 region.

[0256] The thickness of the B1 region is 0. The thicknesses of the B2 region, the B3 region, and the B4 region are set in the same manner as the thicknesses of the A2 region and the A3 region described above.

[0257] When the dielectric member has a third dielectric layer, a first dielectric layer, and a second dielectric layer in this order from the reflecting member side, as shown in, for example, Figure 34 (a), the dielectric member 5 has, from the reflecting member 2 side, a C1 region 51 which does not have the third dielectric pattern 13P, the first dielectric pattern 11P, and the second dielectric pattern 12P, a C2 region 52 which has only the third dielectric pattern 13P from the reflecting member 2 side, a C3 region 53 which has only the third dielectric pattern 13P and the first dielectric pattern 11P from the reflecting member 2 side, and a C4 region 54 which has the third dielectric pattern 13P, the first dielectric pattern 11P, and the second dielectric pattern 12P from the reflecting member 2 side.

[0258] In the above case, the thickness of the C1 region is 0, and the thicknesses of the C1 region, C2 region, C3 region, and C4 region are different from one another. Therefore, the round-trip optical path length in the dielectric member is changed in the C1 region, C2 region, C3 region, and C4 region, and the reflection phase of the electromagnetic wave can be controlled. This makes it possible to control the reflection direction of the electromagnetic wave relative to a predetermined incident direction to any direction.

[0259] The absolute value of the difference between the relative reflection phase of the electromagnetic wave in the C1 region and the relative reflection phase of the electromagnetic wave in the C2 region, the absolute value of the difference between the relative reflection phase of the electromagnetic wave in the C2 region and the relative reflection phase of the electromagnetic wave in the C3 region, and the absolute value of the difference between the relative reflection phase of the electromagnetic wave in the C3 region and the relative reflection phase of the electromagnetic wave in the C4 region are similar to the absolute value of the difference between the relative reflection phase of the electromagnetic wave in the B1 region and the relative reflection phase of the electromagnetic wave in the B2 region, the absolute value of the difference between the relative reflection phase of the electromagnetic wave in the B2 region and the relative reflection phase of the electromagnetic wave in the B3 region, and the absolute value of the difference between the relative reflection phase of the electromagnetic wave in the B3 region and the relative reflection phase of the electromagnetic wave in the B4 region.

[0260] In the above case, the thickness of the C1 region is 0, and the thicknesses of the C2 region, the C3 region and the C4 region are set in the same manner as the thicknesses of the B2 region, the B3 region and the B4 region described above.

[0261] When the dielectric member has a first dielectric layer, a third dielectric layer, and a second dielectric layer in this order from the reflecting member side, as shown in Figure 34 (b), for example, the dielectric member 5 has, from the reflecting member 2 side, a D1 region 61 which does not have the first dielectric pattern 11P, the third dielectric pattern 13P, and the second dielectric pattern 12P, a D2 region 62 which has only the first dielectric pattern 11P from the reflecting member 2 side, a D3 region 63 which has only the first dielectric pattern 11P and the third dielectric pattern 13P from the reflecting member 2 side, and a D4 region 64 which has the first dielectric pattern 11P, the third dielectric pattern 13P, and the second dielectric pattern 12P from the reflecting member 2 side.

[0262] In the above case, the thickness of the D1 region is 0, and the thicknesses of the D1 region, the D2 region, the D3 region, and the D4 region are different from one another. Therefore, the D1 region, the D2 region, the D3 region, and the D4 region change the round-trip optical path length in the dielectric member, thereby controlling the reflection phase of the electromagnetic wave. This allows the reflection direction of the electromagnetic wave relative to a predetermined incident direction to be controlled to any direction.

[0263] The absolute value of the difference between the relative reflection phase of the electromagnetic wave in the D1 region and the relative reflection phase of the electromagnetic wave in the D2 region, the absolute value of the difference between the relative reflection phase of the electromagnetic wave in the D2 region and the relative reflection phase of the electromagnetic wave in the D3 region, and the absolute value of the difference between the relative reflection phase of the electromagnetic wave in the D3 region and the relative reflection phase of the electromagnetic wave in the D4 region are similar to the absolute value of the difference between the relative reflection phase of the electromagnetic wave in the B1 region and the relative reflection phase of the electromagnetic wave in the B2 region, the absolute value of the difference between the relative reflection phase of the electromagnetic wave in the B2 region and the relative reflection phase of the electromagnetic wave in the B3 region, and the absolute value of the difference between the relative reflection phase of the electromagnetic wave in the B3 region and the relative reflection phase of the electromagnetic wave in the B4 region.

[0264] In the above case, the thickness of the D1 region is 0, and the thicknesses of the D2 region, the D3 region, and the D4 region are set in the same manner as the thicknesses of the B2 region, the B3 region, and the B4 region described above.

[0265] When the dielectric member has three or more dielectric layers, the dielectric layers other than the first and second dielectric layers have a dielectric pattern, similar to the first and second dielectric layers. When the number of stacked dielectric layers is n, the dielectric member has n+1 regions. Each region can be considered in the same way as when the above-mentioned dielectric member has the first, second, and third dielectric layers as dielectric layers.

[0266] The pitch of each region is set appropriately according to the desired reflection characteristics. When the dielectric member has regions A1 to A3, the pitch of region A1 is shifted by one wavelength (phase difference: 360 degrees) per pitch. Similarly, the pitch of regions A2 and A3 is shifted by one wavelength (phase difference: 360 degrees) per pitch. The same applies to the pitch of the other regions. Therefore, the reflection angle can be adjusted by the pitch of each region. For example, by shortening the pitch of each region, the difference in the reflection angle from the specular reflection angle can be increased. On the other hand, by lengthening the pitch of each region, the difference in the reflection angle from the specular reflection angle can be reduced.

[0267] Furthermore, when the reflective member is a member in which a plurality of reflective elements are arranged, the pitch of each region may be the same as or different from the pitch of the reflective elements of the reflective member. If the pitch of each region is the same as the pitch of the reflective elements of the reflective member, the design is easier. Furthermore, for example, by adjusting the pitch of each region, the control range of the reflection characteristics can be expanded regardless of the pitch of the reflective elements of the reflective member.

[0268] The pitch of each region is appropriately designed depending on the desired reflection characteristics, and the pitch of each region may be uniform or non-uniform throughout the dielectric member.

[0269] The pitch of the A1 regions refers to the distance from the center of one A1 region to the center of the adjacent A1 region. The pitch of the A2 regions refers to the distance from the center of one A2 region to the center of the adjacent A2 region. The pitch of the A3 regions refers to the distance from the center of one A3 region to the center of the adjacent A3 region. The same applies to the pitches of the other regions.

[0270] The size of each region is appropriately designed depending on the desired reflection characteristics, and the size of each region may be uniform or non-uniform throughout the dielectric member.

[0271] The shape of each region in a plan view is not particularly limited as long as it allows the regions to be arranged without gaps. The shape of each region in a plan view throughout the dielectric member may be uniform or non-uniform.

[0272] In the dielectric member, the arrangement of each region is appropriately set according to the desired reflection characteristics. Typically, each region is arranged so that its thickness repeatedly increases and decreases in a certain direction. The direction of the arrangement of each region is not particularly limited. Depending on the required reflection characteristics design, an appropriate arrangement angle and an appropriate arrangement direction may be selected to arrange each region.

[0273] In the dielectric member, the thickness of each region affects the overall reflection characteristics of the frequency selective reflector, but the pitch of each region, the size of each region, the shape of each region in plan view, the arrangement of each region, etc. also affect the overall reflection characteristics of the frequency selective reflector. Specifically, examples include the effects on adjustment of polarization characteristics and beam profile (high directivity, diffusion, multi-beam, etc.).

[0274] In the dielectric member, the thickness distribution of the dielectric member is appropriately selected and each region is arranged so that the normal vector of the same phase plane of the reflected wave relative to the incident wave incident at a predetermined incident angle is in the desired reflection direction.

[0275] For example, when an incident plane wave is reflected in a single direction, i.e., as a so-called plane wave, it is preferable that the pitch, width, and planar shape of each region are uniform throughout the entire dielectric member. In this case, it is more preferable that the regions are arranged in a stripe pattern. For example, in FIG. 35 , the pitch, width, and planar shape of the A1 region 31, A2 region 32, and A3 region 33 are uniform throughout the entire dielectric member 5. Furthermore, the A1 region 31, A2 region 32, and A3 region 33 are arranged in a stripe pattern. In this case, as illustrated in FIG. 2 , an incident wave W1 incident at a predetermined incident angle θ1 can be reflected at a predetermined reflection angle θ2, and the reflected wave W2 can be a plane wave without spreading. Furthermore, when the frequency selective reflector has a rectangular shape in plan view and the regions are arranged in a striped pattern, the longitudinal direction of the stripes in each region may be parallel to the short side direction of the frequency selective reflector, or the longitudinal direction of the stripes in each region may be parallel to the long side direction of the frequency selective reflector. In an actual frequency selective reflector, the longitudinal and short side directions of the stripes in each region can be set arbitrarily depending on the design of the reflection characteristics.

[0276] Furthermore, for example, when electromagnetic waves are diffused, for example, reflected as cylindrical waves, the dielectric member 5 may have multiple periodic structures with different reflection characteristics. For example, in FIG. 36( a), the dielectric member 5 has three types of periodic structures 71-73. These periodic structures 71-73 have different widths (w1, w2, w3) of the A1 region 31, different widths (w11, w12, w13) of the A2 region 32, and different widths (w21, w22, w23) of the A3 region 33, and different pitches (p1, p2, p3) of the A1 region 31. As a result, the three types of periodic structures 71-73 have different reflection characteristics. Furthermore, as shown in FIG. 36( b), the relative reflection phases of electromagnetic waves in the A1 region 31, A2 region 32, and A3 region 33 of the dielectric member 5 are 0 degrees (−360 degrees), −120 degrees, and −240 degrees, respectively. The A1 regions 31, A2 regions 32, and A3 regions 33 are arranged in a stripe pattern. In this case, as illustrated in FIG. 6, an incident wave W1 incident at a predetermined incident angle θ1 can be reflected at reflection angles θ2, θ2', and θ2" according to the periodic structure, resulting in a broadened reflection, and the wavefront of the reflected wave W2 can be broadened.

[0277] Furthermore, for example, when a spherical wave is reflected as a plane wave, the regions are preferably arranged in an arc stripe pattern.

[0278] Furthermore, the dielectric member may have a plurality of reflective regions with different reflective characteristics, and the plurality of reflective regions may be arranged in a plane. For example, in FIG. 37 , the dielectric member 5 has two types of reflective regions 81 and 82 with different reflective characteristics, and the two types of reflective regions 81 and 82 are arranged in a plane. In these reflective regions 81 and 82, for example, the widths of the A1 region 31, the A2 region 32, and the A3 region 33 are different from each other, and the pitch of the A1 region 31 is different from each other. As a result, the two types of reflective regions 81 and 82 have different reflective characteristics. In this manner, it is possible to accommodate a plurality of coverage holes.

[0279] Furthermore, for example, when the reflecting member described below is a frequency selective surface having multiple types of frequency selective surfaces (FSS) that selectively reflect electromagnetic waves in different frequency bands, the reflection characteristics of the dielectric member may be designed according to the frequency selectivity of the frequency selective surfaces, and the dielectric member may have regions with different reflection characteristics. In this case, too, an arrangement such as that shown in Figure 37 may be used. In this embodiment, dual bands or more bands can be supported.

[0280] Furthermore, when the incident wave and the reflected wave are plane waves, the dielectric member has a periodic structure in which each region is repeatedly arranged. A "periodic structure" refers to a structure in which each region is periodically and repeatedly arranged. In a periodic structure in which the reflection characteristics of each region are identical, the width, pitch, planar shape, and arrangement of each region can be the same for each region. Even when the dielectric member has a periodic structure, as described above, periodic structures with different reflection characteristics can be combined. In this case, the reflection characteristics of the combined periodic structures are appropriately designed according to the desired reflection characteristics. Specifically, the width, pitch, planar shape, and arrangement of each region in the combined periodic structures are appropriately set according to the desired reflection characteristics.

[0281] The general design of reflection characteristics for reflecting a plane wave as a plane wave in a direction different from the specular reflection direction is the same as that described in the first embodiment.

[0282] (6) Characteristics of Dielectric Member The dielectric member is only required to transmit electromagnetic waves in a specific frequency band, and may or may not transmit electromagnetic waves in other frequency bands.

[0283] The dielectric loss tangent and dielectric constant of each dielectric layer constituting the dielectric member are the same as those of the dielectric layer in the first embodiment.

[0284] (7) Material of Dielectric Layer The material of each dielectric layer constituting the dielectric member is the same as the material of the dielectric layer in the first embodiment.

[0285] The materials of the dielectric layers may be the same or different from each other. When the materials of the dielectric layers are different, the thickness of the dielectric layers can be adjusted by appropriately selecting the dielectric constant for each dielectric layer. Furthermore, since the total area of ​​the dielectric patterns of the dielectric parts constituting the upper dielectric layer is smaller than the total area of ​​the dielectric patterns of the dielectric parts constituting the lower dielectric layer, by using different materials for each dielectric layer, the strength and processability of each dielectric layer can be adjusted.

[0286] (8) Supporting Part In the present disclosure, the first dielectric part constituting the first dielectric layer preferably has a first supporting part supporting the first dielectric pattern. Similarly, the second dielectric part constituting the second dielectric layer preferably has a second supporting part supporting the second dielectric pattern. Furthermore, when the dielectric member has three or more dielectric layers, the dielectric parts constituting the dielectric layers other than the first and second dielectric layers preferably have supporting parts supporting the dielectric patterns. The strength of the dielectric part can be increased by having supporting parts. Furthermore, the supporting parts can connect the dielectric patterns and integrate them, making it easier to form the dielectric part.

[0287] The position of the support portion is not particularly limited as long as it can connect the dielectric patterns and integrate them. The support portion is preferably arranged on the outer periphery of the dielectric portion, and more preferably arranged in a frame shape on the outer periphery of the dielectric portion. Furthermore, the support portion may be arranged inside the dielectric portion other than on the outer periphery.

[0288] 19 and 38, for example, the first dielectric portion 11a has first support portions 11S that support the first dielectric pattern 11P. In Fig. 19, the first support portions 11S are arranged only on the outer periphery of the first dielectric portion 11a. In Fig. 38, the first support portions 11S are arranged on the outer periphery and inside of the first dielectric portion 111a. Furthermore, in Fig. 20, for example, the second dielectric portion 12a has second support portions 12S that support the second dielectric pattern 12P, and the second support portions 12S are arranged only on the outer periphery of the second dielectric portion 12a.

[0289] The thickness of the support part may be the same as the thickness of the dielectric part, or may be thinner than the thickness of the dielectric part. When the thickness of the support part is thinner than the thickness of the dielectric part, the influence of the support part on the reflection characteristics can be reduced. In the case of cutting processes such as cutting and laser processing, the thickness of the support part is usually the same as the thickness of the dielectric part. In the case of a 3D printer, the thickness of the support part can be adjusted.

[0290] The width of the support portion is preferably a width that does not affect the reflection characteristics. When the thickness of the support portion is approximately the same as the thickness of the dielectric portion, the width of the support portion is preferably λ or less, more preferably λ / 2 or less, where λ is the wavelength of the electromagnetic wave. If the width of the support portion is too large, it may affect the reflection characteristics. Furthermore, if the width of the support portion is λ / 2 or less, resonance is unlikely to occur, and the reflection intensity of the electromagnetic wave will drop sharply. On the other hand, the lower limit of the width of the support portion is not particularly limited as long as it is a width that can support the dielectric pattern.

[0291] Specifically, the width of the support portion is preferably 0.05 mm to 2 mm, more preferably 0.1 mm to 1 mm, and even more preferably 0.2 mm to 0.5 mm. If the width of the support portion is too small, it may be difficult to form the support portion or to support the dielectric pattern. Furthermore, if the width of the support portion is too large, it may affect the reflection characteristics.

[0292] In a dielectric layer having a plurality of dielectric portions arranged side by side, the support portions located on the periphery of the dielectric layer are considered not to affect the reflection characteristics, and therefore the width of the support portions located on the periphery of the dielectric layer is not particularly limited and may be within the above range or may be outside the above range.

[0293] In the dielectric section, the width of the support section located on the outer periphery of the dielectric section may be the same as or different from the width of the support section located inside the dielectric section other than the outer periphery.

[0294] Furthermore, in a dielectric layer in which a plurality of dielectric portions are arranged side by side, when each dielectric portion has a support portion, the ratio of the total area of ​​the support portions to the outer area of ​​the dielectric layer is preferably 30% or less, more preferably 20% or less, and even more preferably 10% or less. If this ratio is too high, the performance of the frequency selective reflector may be reduced. On the other hand, the lower limit of this ratio is not particularly limited as long as the support portions can support the dielectric pattern. In this case, as mentioned above, the support portions located on the outer periphery of the dielectric layer are not considered to affect the reflection characteristics, and therefore are not included in the total area of ​​the support portions.

[0295] Here, the ratio of the total area of ​​the supporting portions to the outer area of ​​the dielectric layer is measured by the following method. First, a region having a size of 1 / 16 of the entire dielectric layer is randomly selected. The ratio of the total area of ​​the supporting portions to the area of ​​this selected region is calculated. If the ratio is within the above range, the ratio in the selected region is considered to be the ratio of the total area of ​​the supporting portions to the outer area of ​​the dielectric layer. On the other hand, if the ratio exceeds the above range, the ratio of the total area of ​​the supporting portions to the outer area of ​​the dielectric layer is further calculated for the entire dielectric layer. The outer area of ​​the dielectric layer refers to the area of ​​the region surrounded by the outermost contour of the dielectric layer when the dielectric layer is viewed in plan.

[0296] In particular, it is preferable that the width of the supporting portion is within the above range, and the ratio of the total area of ​​the supporting portion to the outer area of ​​the dielectric layer is within the above range.

[0297] The shape of the support portion in plan view is not particularly limited, and examples thereof include a lattice shape and a stripe shape.

[0298] When the first dielectric portion of the first dielectric layer has a first support portion and the second dielectric portion of the second dielectric layer has a second support portion, and when the thickness of the first support portion is approximately the same as that of the first dielectric portion and the thickness of the second support portion is approximately the same as that of the second dielectric portion, it is preferable that the first dielectric portion and the second dielectric portion are arranged so that the first support portion of the first dielectric portion and the second support portion of the second dielectric portion overlap in a plan view, thereby suppressing distortion of the wavefront of the reflected wave.

[0299] On the other hand, when the first dielectric portion of the first dielectric layer has a first support portion and the second dielectric portion of the second dielectric layer has a second support portion, and the thickness of the first support portion is thinner than the thickness of the first dielectric portion and the thickness of the second support portion is thinner than the thickness of the second dielectric portion, the first dielectric portion and the second dielectric portion may be arranged so that the first support portion of the first dielectric portion and the second support portion of the second dielectric portion overlap in a planar view, or the first dielectric portion and the second dielectric portion may be arranged so that the first support portion of the first dielectric portion and the second support portion of the second dielectric portion do not overlap.

[0300] When a dielectric member has three or more dielectric layers, and the dielectric portion constituting each dielectric layer has a support portion, and the thickness of the support portion is approximately the same as the thickness of the dielectric portion, it is preferable that the dielectric portion constituting the upper dielectric layer and the dielectric portion constituting the lower dielectric layer are arranged so that the support portions of the dielectric portions overlap in a planar view.

[0301] On the other hand, when the dielectric member has three or more dielectric layers, and the dielectric portion constituting each dielectric layer has a support portion, and the thickness of the support portion is thinner than the thickness of the dielectric portion, the dielectric portion constituting the upper dielectric layer and the dielectric portion constituting the lower dielectric layer may be arranged so that the support portions of the dielectric portions overlap in a planar view, or the dielectric portion constituting the upper dielectric layer and the dielectric portion constituting the lower dielectric layer may be arranged so that the support portions of the dielectric portions do not overlap.

[0302] (9) Method for Forming Dielectric Layer The method for forming the dielectric layer is the same as the method for forming the dielectric layer in the first embodiment.

[0303] (10) Stacking Method of Dielectric Layers In a dielectric member, dielectric layers are stacked. To increase strength, the dielectric layers are preferably bonded together. Examples of methods for bonding dielectric layers include a method of placing an adhesive layer between an upper dielectric layer and a lower dielectric layer, a method of welding the upper dielectric layer and the lower dielectric layer, and a method of fixing the dielectric portions constituting each dielectric layer with pins that penetrate in the thickness direction. In the bonding method using an adhesive layer and the welding method, the upper dielectric layer and the lower dielectric layer are bonded together.

[0304] The welding method may be heat welding or solvent welding. In the case of heat welding, a meltable material is used for the material of each dielectric layer. In the case of solvent welding, a solvent-soluble material is used for the material of each dielectric layer.

[0305] Among these, the bonding method using an adhesive layer is preferred, as it can bond the entire surface of the dielectric portion, thereby preventing moisture, gas, etc. from entering the inside of the dielectric member.

[0306] (a) Adhesive Layer The dielectric member may have an adhesive layer between the upper dielectric layer and the lower dielectric layer. The adhesive layer bonds the upper dielectric layer and the lower dielectric layer. For example, in FIG. 32( a), an adhesive layer 16a is disposed between the first dielectric layer 11 and the second dielectric layer 12.

[0307] For example, an adhesive can be used for the adhesive layer, and can be appropriately selected from known adhesives. In this case, the adhesive must be non-conductive. Furthermore, if the adhesive is liquid, it is preferable that it can be spread evenly and has fluidity sufficient to remove trapped air bubbles. Furthermore, if the adhesive is in sheet form, it is preferable that it has a uniform thickness and flexibility sufficient to conform to the unevenness of the bonding interface and prevent trapped air bubbles.

[0308] The thickness of the adhesive layer is preferably uniform and is a thickness that can obtain a desired adhesive strength. The thickness of the adhesive layer is also preferably sufficiently smaller than the effective wavelength of the target electromagnetic wave, and the effective wavelength of the electromagnetic wave is preferably λ ｇ Specifically, 0.01λ ｇ The following is preferred:

[0309] Furthermore, when an adhesive layer is provided, an additional adhesive layer may be provided between adjacent dielectric portions in each dielectric layer. If the material of the dielectric layer has low weather resistance, covering the dielectric portion with an adhesive layer can prevent moisture, gas, etc. from entering the dielectric member, thereby improving durability. For example, in Figure 32(a), an adhesive layer 16b is provided between adjacent first dielectric portions 11a and 11b, and adhesive layers 16b are provided between adjacent second dielectric portions 12a and 12b and between adjacent second dielectric portions 12b and 12c.

[0310] When applying the adhesive, the application method is not particularly limited. For example, in the case of a dip coating method, the adhesive can be easily applied to the entire surface of the dielectric portion, and the process can be shortened.

[0311] (b) Pins In the dielectric member, the dielectric portions constituting each dielectric layer may be fixed by pins penetrating in the thickness direction. Even if the distance between the boundary between adjacent dielectric portions in the upper dielectric layer and the boundary between adjacent dielectric portions in the lower dielectric layer is short, the dielectric portions constituting each dielectric layer can be firmly joined in the thickness direction of the dielectric portions. This increases the strength of the dielectric member. For example, in Figure 32(b), the first dielectric portions 11a, 11b and the second dielectric portions 12a, 12b, 12c are fixed by pins 17 penetrating the first dielectric portions 11a, 11b and the second dielectric portions 12a, 12b, 12c.

[0312] The position of the pin is not particularly limited as long as it can join the dielectric portions constituting each dielectric layer in the thickness direction of the dielectric member. The pin may be arranged on the dielectric pattern in the dielectric portion or on the support portion.

[0313] The material of the pins is preferably the same as the material of the dielectric layer, which reduces the influence of the pins on the reflection characteristics.

[0314] The height of the pin may be lower or higher than the thickness of the dielectric member. The height of the pin is usually preferably the same as the thickness of the dielectric member. Specifically, the height of the pin is preferably within ±20% of the thickness of the dielectric member, more preferably within ±10%, and even more preferably within ±5%. As will be described later, when a protective member is disposed on the surface of the dielectric member opposite the reflective member, if the pin height is too high, it may be difficult to dispose the protective member. Furthermore, if the pin height is too low, the stability of the bonding of each dielectric portion in the thickness direction of the dielectric member may be reduced.

[0315] In plan view, the size of the pin is preferably large enough not to affect the reflection characteristics. For example, if the pin has a circular shape in plan view, the diameter of the pin is preferably λ or less, and more preferably λ / 2 or less, where λ is the wavelength of the electromagnetic wave. If the pin size is too large, it may affect the reflection characteristics. Furthermore, if the pin size is λ / 2 or less, resonance is unlikely to occur, and the reflection intensity of the electromagnetic wave drops sharply. On the other hand, the lower limit of the pin size is not particularly limited as long as it is large enough to join the dielectric portions that make up each dielectric layer.

[0316] The shape of the pin in plan view is not particularly limited, and may be, for example, circular.

[0317] As a method for arranging the pins, for example, a method in which through holes are formed in the thickness direction in the dielectric portion constituting each dielectric layer and the pins are inserted into the through holes can be mentioned.

[0318] (11) Alignment of Dielectric Portions In the present disclosure, alignment marks on the substrate can be used to align the multiple dielectric portions constituting each dielectric layer. Misalignment of the dielectric portions relative to one another can reduce the reflection intensity of the electromagnetic wave or change the reflection phase of the electromagnetic wave. By using the alignment marks on the substrate, the dielectric portions can be aligned with high precision. This makes it easier to obtain desired reflection characteristics.

[0319] The alignment of the first dielectric portions constituting the first dielectric layer will be described below using an example. For convenience, the alignment marks on the substrate will be referred to as first alignment marks, and the alignment marks on the first dielectric portions will be referred to as second alignment marks.

[0320] For example, the dielectric layer may be aligned by aligning the edge of the first dielectric portion with reference to the first alignment mark on the substrate. Alternatively, the first dielectric portion may have a second alignment mark, and the first dielectric portion may be aligned by aligning the second alignment mark on the first dielectric portion with reference to the first alignment mark on the substrate.

[0321] 23 , for example, the substrate 21 has a cross-shaped first alignment mark 22, and the edges of the first dielectric portions 11 a, 11 b are aligned using the first alignment mark 22 of the substrate 21 as a reference, thereby aligning the first dielectric portions 11 a, 11 b. Specifically, when the first dielectric pattern is opaque, the substrate is optically transparent, and the first alignment mark is optically opaque, the first alignment mark of the substrate and the edges of the first dielectric portion can be detected by transmitted light, and the first dielectric portion can be aligned. Furthermore, when the first dielectric pattern is optically reflective, and the first alignment mark is optically reflective, the first alignment mark of the substrate and the edges of the first dielectric portion can be detected by reflected light, and the first dielectric portion can be aligned.

[0322] 39, for example, the substrate 21 has a circular first alignment mark 22, the first dielectric portion 11a has a hollowed-out circular second alignment mark 24, and the first dielectric portion 11a is aligned by aligning the position of the second alignment mark 24 of the first dielectric portion 11a with reference to the first alignment mark 22 of the substrate 21. Specifically, when the substrate 21 is optically transparent, the first alignment mark 22 is optically opaque, and the second alignment mark 24 is optically opaque, the first alignment mark 22 of the substrate 21 and the second alignment mark 24 of the first dielectric portion 11a can be detected by transmitted light, and the first dielectric portion 11a can be aligned. Furthermore, if the first alignment mark 22 is optically reflective and the second alignment mark 24 is optically reflective, the first alignment mark 22 on the substrate 21 and the second alignment mark 24 on the first dielectric part 11a can be detected by reflected light, and the first dielectric part 11a can be aligned.

[0323] The reflecting elements constituting the reflecting member may be optically opaque or optically reflective. Even in such cases, for example, by making the size of the reflecting element significantly different from the sizes of the first alignment mark and the second alignment mark, it is possible to distinguish between the light transmitted or reflected by the first alignment mark and the second alignment mark and the light transmitted or reflected by the reflecting element. This makes it possible to align the frequency selective reflector.

[0324] 40 , for example, the substrate 21 has a cross-shaped first alignment mark 22, and the first dielectric portion 11a has a second alignment mark 24 that is a square-shaped through-hole. The first dielectric portion 11a is aligned by aligning the second alignment mark 24 of the first dielectric portion 11a with the first alignment mark 22 of the substrate 21 as a reference. Specifically, if the substrate 21 is optically transparent and the first alignment mark 22 is optically opaque, the first alignment mark 22 of the substrate 21 can be detected by transmitted light through the through-hole (second alignment mark 24) of the first dielectric portion 11a, thereby aligning the first dielectric portion 11a. If the first alignment mark 22 is optically reflective, the first alignment mark 22 of the substrate 21 can be detected by reflected light through the through-hole (second alignment mark 24) of the first dielectric portion 11a, thereby aligning the first dielectric portion 11a.

[0325] The alignment of the plurality of second dielectric portions constituting the second dielectric layer is similar to the alignment of the plurality of first dielectric portions constituting the first dielectric layer described above.

[0326] Furthermore, when the dielectric member has three or more dielectric layers, the alignment of the multiple dielectric portions constituting the dielectric layers other than the first dielectric layer and the second dielectric layer is similar to the alignment of the multiple first dielectric portions constituting the first dielectric layer described above.

[0327] (a) Second Alignment Mark In the present disclosure, the first dielectric portion constituting the first dielectric layer and the second dielectric portion constituting the second dielectric layer may have alignment marks. The alignment mark of the first dielectric portion is a mark for aligning the first dielectric portion. Also, the alignment mark of the second dielectric portion is a mark for aligning the second dielectric portion.

[0328] Furthermore, when the dielectric member has three or more dielectric layers, the multiple dielectric portions constituting the dielectric layers other than the first dielectric layer and the second dielectric layer may have alignment marks, similar to the first dielectric portion and the second dielectric portion.

[0329] The alignment mark of the first dielectric portion constituting the first dielectric layer will be described below by way of example. For convenience, the alignment mark of the first dielectric portion will be referred to as the second alignment mark.

[0330] The second alignment mark may be opaque or reflective, and the optical properties of the second alignment mark may be appropriately selected depending on whether the second alignment mark is to be detected by transmitted light or reflected light.

[0331] The transmittance and reflectance of the second alignment mark are not particularly limited as long as the second alignment mark can be detected by transmitted or reflected light, and can be set appropriately depending on the material, thickness, etc. of the second alignment mark.

[0332] The second alignment mark may also be a through-hole that penetrates the first dielectric pattern.

[0333] The shape of the second alignment mark in plan view is not particularly limited and is similar to the shape of a general alignment mark in plan view. Specific examples of the shape of the second alignment mark in plan view are similar to the shape of the first alignment mark in plan view.

[0334] The size or line width of the second alignment mark is not particularly limited as long as the second alignment mark can be detected, but it is preferable that the size or line width be such that it does not affect the reflection characteristics. When the wavelength of the electromagnetic wave is λ, the size of the second alignment mark is preferably λ × λ or less, more preferably λ / 2 × λ / 2 or less. When the wavelength of the electromagnetic wave is λ, the line width of the second alignment mark is preferably λ or less, more preferably λ / 2 or less. If the size or line width of the second alignment mark is too large, it may affect the reflection characteristics. Furthermore, if the size of the second alignment mark is λ / 2 × λ / 2 or less, or if the line width of the second alignment mark is λ / 2 or less, resonance is unlikely to occur, and the reflection intensity of the electromagnetic wave will rapidly decrease. On the other hand, the lower limit of the size or line width of the second alignment mark is not particularly limited as long as the second alignment mark can be detected.

[0335] The number of second alignment marks is not particularly limited as long as it is possible to align the first dielectric portion.

[0336] Furthermore, the ratio of the total area of ​​the second alignment marks to the total area of ​​the first dielectric portion is preferably 20% or less, more preferably 10% or less, and even more preferably 5% or less. If this ratio is too high, the performance of the frequency selective reflector may be reduced. On the other hand, the lower limit of this ratio is not particularly limited as long as the second alignment marks can be detected.

[0337] The method for measuring the ratio of the total area of ​​the second alignment marks to the total area of ​​the first dielectric portion is the same as the method for measuring the ratio of the total area of ​​the supporting portions to the total area of ​​the dielectric portion described above.

[0338] The position of the second alignment mark in the first dielectric part is not particularly limited, but it is preferable that the second alignment mark be arranged on the first support part of the first dielectric part, and it is more preferable that the second alignment mark be arranged on the first support part located on the outer periphery of the first dielectric part.

[0339] The second alignment mark may be disposed on the surface of the first dielectric part facing the reflecting member, or on the surface of the first dielectric part opposite the reflecting member.

[0340] The thickness of the second alignment mark is not particularly limited as long as it allows the second alignment mark to be formed with high precision, and is adjusted appropriately depending on the optical characteristics of the second alignment mark, etc.

[0341] The material and method of forming the second alignment mark are the same as those of the first alignment mark.

[0342] The alignment mark provided in the second dielectric portion constituting the second dielectric layer is similar to the second alignment mark provided in the first dielectric portion constituting the first dielectric layer described above.

[0343] Furthermore, when the dielectric member has three or more dielectric layers, the alignment marks possessed by the dielectric portions constituting the dielectric layers other than the first dielectric layer and the second dielectric layer are similar to the second alignment marks possessed by the first dielectric portion constituting the above-mentioned first dielectric layer.

[0344] (b) Second Identification Mark In the present disclosure, the plurality of first dielectric portions constituting the first dielectric layer may have an identification mark for identifying the first dielectric portion, and the plurality of second dielectric portions constituting the second dielectric layer may have an identification mark for identifying the second dielectric portion.

[0345] Furthermore, when the dielectric member has three or more dielectric layers, the multiple dielectric portions constituting the dielectric layers other than the first dielectric layer and the second dielectric layer may have identification marks for identifying the dielectric portions.

[0346] The identification marks on the dielectric portions constituting each dielectric layer make it easy to identify each dielectric portion and also make it easy to distinguish between the top, bottom, left, right, front and back of each dielectric portion, so that each dielectric portion can be reliably and easily positioned in the correct position. This is particularly useful when the dielectric member has multiple reflective regions with different reflective properties.

[0347] The identification mark on the first dielectric portion constituting the first dielectric layer will be described below by way of example. For convenience, the identification mark on the first dielectric portion will be referred to as the second identification mark.

[0348] For example, in FIG. 24, the first dielectric portions 11a and 11b have second identification marks 25 labeled "No. 1" and "No. 2," respectively.

[0349] The second identification mark may be opaque or reflective, and the optical characteristics of the second identification mark are appropriately selected depending on whether the second identification mark is to be detected by transmitted light or reflected light, as with the second alignment mark.

[0350] The transmittance and reflectance of the second identification mark are not particularly limited as long as the second identification mark can be detected by transmitted light or reflected light, and can be set appropriately depending on the material, thickness, etc. of the second identification mark.

[0351] The second identification mark is not particularly limited as long as it is an identifiable mark, and examples thereof include letters, symbols, figures, etc. Specific examples include codes. The second identification mark may also be data that can be recognized by optical character recognition (OCR).

[0352] The size or line width of the second identification mark is not particularly limited as long as the second identification mark can be detected, and is the same as the size or line width of the second alignment mark described above.

[0353] The position of the second identification mark in the first dielectric part is not particularly limited as long as it allows each first dielectric part to be identified, but it is preferable that the second identification mark be placed on the first support part of the first dielectric part, and it is more preferable that the second identification mark be placed on the first support part located on the outer periphery of the first dielectric part.

[0354] The second identification mark may be disposed on the surface of the first dielectric part facing the reflective member, or on the surface of the first dielectric part opposite the reflective member.

[0355] The thickness, material, and formation method of the second identification mark are the same as those of the second alignment mark.

[0356] If the material of the second identification mark is the same as the material of the second alignment mark, the second alignment mark and the second identification mark can be formed simultaneously.

[0357] The identification mark on the second dielectric portion constituting the second dielectric layer is the same as the second identification mark on the first dielectric portion constituting the first dielectric layer described above.

[0358] Furthermore, when the dielectric member has three or more dielectric layers, the identification marks possessed by the dielectric portions constituting the dielectric layers other than the first dielectric layer and the second dielectric layer are the same as the second identification mark possessed by the first dielectric portion constituting the above-mentioned first dielectric layer.

[0359] (c) Concave and Convex Portions In the first dielectric layer of this embodiment, adjacent first dielectric portions may have concave and convex portions on their opposing side surfaces that can fit together, and the adjacent first dielectric portions may be arranged so that the concave and convex portions fit together. The fit of the concave and convex portions facilitates the alignment of multiple first dielectric portions. Furthermore, the increased contact area between adjacent first dielectric portions can enhance strength.

[0360] Furthermore, similar to the first dielectric layer described above, in the second dielectric layer in this embodiment, adjacent second dielectric portions may have uneven portions on their opposing side surfaces that can fit together, and the adjacent second dielectric portions may be arranged so that the uneven portions fit together.

[0361] Furthermore, when the dielectric member has three or more dielectric layers, similar to the first dielectric layer described above, adjacent dielectric portions in dielectric layers other than the first dielectric layer and the second dielectric layer may have uneven portions on opposing side surfaces that can fit together, and the adjacent dielectric portions may be arranged so that the uneven portions fit together.

[0362] For example, in Figures 41 and 42, in the first dielectric layer, adjacent first dielectric portions 11a have uneven portions 26 on their opposing side surfaces that can fit together, and the adjacent first dielectric portions are arranged so that the uneven portions 26 fit together.

[0363] 42, for example, the number of concave-convex portions 26 in each first dielectric portion 11a is different from one another. In this way, when the number, shape, size, etc. of the concave-convex portions are different from one another in each first dielectric portion, the first dielectric portions can be distinguished. Therefore, each first dielectric portion can be easily distinguished, and the top, bottom, left, right, front, and back of each first dielectric portion can be easily distinguished, so that each first dielectric portion can be reliably and easily placed in the correct position.

[0364] The shape of the concave and convex portions is not particularly limited as long as they are shapes that allow engagement.

[0365] The number and size of the uneven portions are not particularly limited as long as the uneven portions can be formed on the side surfaces of the dielectric portions that constitute each dielectric layer.

[0366] It is preferable that the thickness of the concave and convex portions of adjacent dielectric portions is the same, which makes it easier to align the adjacent dielectric portions.

[0367] The concave and convex portions do not have to fit together without any gaps on the opposing side surfaces of adjacent dielectric portions, that is, there may be gaps between the fitted concave and convex portions.

[0368] 3. Reflecting Member The reflecting member in this embodiment is a member that reflects electromagnetic waves in a specific frequency band. The reflecting member is similar to the reflecting member in the first embodiment. For example, Fig. 43 shows an example in which the reflecting member 2 is a reflecting layer 7, and the reflecting layer 7 is disposed on the entire surface of the substrate 21. Also, for example, Fig. 21 shows an example in which the reflecting member 2 is a frequency selective surface, and the reflecting member 2 has a dielectric substrate 4 and a plurality of reflecting elements 3 arranged on the surface of the dielectric substrate 4 facing the dielectric member 5.

[0369] When the reflecting member has a dielectric substrate and a plurality of reflecting elements, the dielectric substrate may also serve as the base material.

[0370] When the reflecting member is a frequency selective surface, one reflecting member may be disposed on one surface of the substrate, or a plurality of reflecting members may be disposed side by side.

[0371] When a plurality of reflecting members are arranged side by side on one surface of the base material, the reflecting members are aligned in the same manner as the above-mentioned alignment of the dielectric portion.

[0372] 4. Control of the Reflection Direction of Electromagnetic Waves In the frequency selective reflector of this embodiment, by stacking dielectric layers in the dielectric member and changing the thickness of each region, the round-trip optical path length in the dielectric member in each region can be changed, thereby controlling the relative reflection phase of the electromagnetic wave. Furthermore, by adjusting the pitch, size, and arrangement of each region in addition to the thickness of each region, the reflection direction of electromagnetic waves incident from a predetermined direction can be controlled.

[0373] Furthermore, when the reflecting member is a frequency selective surface and has a reflection phase control function, not only can the round-trip optical path length in the dielectric member be changed by changing the thickness of each region, but also the resonant frequency of each reflecting element can be changed by changing the dimensions and shape of the reflecting element of the reflecting member, thereby controlling the reflection phase of the electromagnetic wave, thereby expanding the degree of freedom in designing for controlling reflection characteristics.

[0374] In this case, it is possible to separate the reflection control direction of the reflecting member from the reflection control direction of the dielectric member, and perform two-dimensional reflection direction control over the entire frequency selective reflector. Also, if the reflection control directions of the reflecting member and the dielectric member are overlapped, for example, a reflection phase distribution that reflects in a certain direction can be realized by the reflecting member, and then fine-tuned by the dielectric member. In this case, there is an advantage that the thickness of the dielectric member can be made thinner.

[0375] As an example of the arrangement of the thickness distribution of the dielectric member and the size distribution of the reflecting elements of the reflecting member, as shown in Figure 44, the dielectric member 5 and the reflecting member 2 can be arranged so that the thickness of the dielectric member 5 increases as the size of the reflecting elements 3 of the reflecting member 2 increases. In this manner, the thickness of the dielectric member can be reduced. This reduces the thickness of the dielectric member, thereby reducing the weight and cost of the frequency selective reflector. Furthermore, even if the reflection angle increases, the reflected wave is less likely to hit the dielectric member.

[0376] Furthermore, as an arrangement of the thickness distribution of the dielectric member and the dimensional distribution of the reflective elements of the reflective member, for example, as shown in Figure 45, the dielectric member 5 and the reflective member 2 may be arranged so that the dimensions of the reflective elements 3 of the reflective member 2 increase along the direction D2 and the thickness of the dielectric member 5 increases along the direction D2.

[0377] In FIG. 45, since the dimensions of the reflecting elements are different, the relative reflection phase of the electromagnetic wave in the unit area where each reflecting element is arranged will differ partially depending on the dimensions of the reflecting element.

[0378] Furthermore, in the case of a specification in which the reflecting member and the dielectric member are designed separately and then combined, the reflection direction of the electromagnetic wave can be fine-tuned by rotating the dielectric member in-plane relative to the reflecting member around the axis of the normal direction and adjusting the arrangement direction of each region of the dielectric member relative to the reflecting member.

[0379] Furthermore, as described above, the reflection characteristics can be controlled by adjusting the pitch of each region in the dielectric member. For example, by shortening the pitch of each region, the reflection angle of the electromagnetic wave can be increased, while by lengthening the pitch of each region, the reflection angle of the electromagnetic wave can be decreased.

[0380] As described above, the in-plane arrangement of each region of the dielectric member that realizes the in-plane distribution design of the reflection phase in the frequency selective reflector does not need to have a fixed positional relationship with the in-plane arrangement of the reflecting elements of the reflecting member, and the reflection characteristics are not significantly affected even if each region of the dielectric member is arranged offset from the in-plane arrangement of the reflecting elements. Therefore, when the reflecting member is a frequency selective surface and a member that has a reflection phase control function, it is possible to design the dielectric member and the reflecting member independently.

[0381] 5. Other Configurations The frequency selective reflector of this embodiment may have other configurations as needed in addition to the reflecting member and the dielectric member described above.

[0382] (1) Adhesive Member The frequency selective reflector of this embodiment may have an adhesive member between the reflecting member and the dielectric member. For example, in Fig. 21(a) , an adhesive member 6 is disposed between the reflecting member 2 and the dielectric member 5. The adhesive member is the same as the adhesive layer in the first embodiment.

[0383] (2) Space The frequency selective reflector of this embodiment may have a space between the reflecting member and the dielectric member. For example, in Fig. 46, a space 8 is provided between the reflecting member 2 and the dielectric member 5.

[0384] When a space is provided between the reflecting member and the dielectric member, it is preferable that the distance between the reflecting member and the dielectric member is constant, so that the optical path length in the space can be made uniform.

[0385] (3) Protective Member The frequency selective reflector of this embodiment may have a protective member on the surface of the dielectric member opposite to the reflecting member. The protective member is the same as the cover member in the first embodiment.

[0386] (4) Ground Layer The frequency selective reflector of this embodiment may have a ground layer on the surface of the reflecting member opposite to the dielectric member. Furthermore, if the reflecting member reflects not only electromagnetic waves in a specific frequency band but also electromagnetic waves in other frequency bands, i.e., does not have wavelength selectivity, the reflecting member may have a reflecting layer that also serves as the ground layer. The ground layer is the same as the ground layer in the first embodiment.

[0387] (5) Planarizing Layer The frequency selective reflector of this embodiment may have a planarizing layer between the reflecting member and the dielectric member. The planarizing layer is the same as the planarizing layer in the first embodiment.

[0388] (6) Fixing Member When the frequency selective reflector of this embodiment is used by attaching it to a wall or the like, a fixing member having a mechanism for attaching the frequency selective reflector may be disposed on the surface of the reflector opposite to the dielectric member. The fixing member is the same as the fixing layer in the first embodiment.

[0389] (7) Antireflection Layer Since the influence of reflection at the interface of the dielectric material may be considered in the case of high frequencies, the frequency selective reflector of this embodiment may have an antireflection layer disposed at the interface between the dielectric material and air, if necessary. The antireflection layer is the same as the antireflection layer in the first embodiment.

[0390] (8) Second Adhesive Member The frequency selective reflector of this embodiment may have a second adhesive member between the substrate and the reflecting member. The second adhesive member is a member for directly or indirectly adhering the reflecting member to the substrate.

[0391] For example, an adhesive can be used as the second adhesive member, and can be appropriately selected from known adhesives and pressure-sensitive adhesives.

[0392] The thickness of the second adhesive member is not particularly limited as long as the desired adhesive strength can be obtained.

[0393] (9) Interference Mitigation Layer The frequency selective reflector of this embodiment may have an interference mitigation layer on the surface of the substrate opposite to the reflecting member, for mitigating changes in characteristics due to interaction with the surface on which the frequency selective reflector is installed. The interference mitigation layer is the same as the interference mitigation layer in the first embodiment.

[0394] 6. Other Features of the Frequency Selective Reflector Other features of the frequency selective reflector of this embodiment are the same as those of the frequency selective reflector of the first embodiment.

[0395] B. Dielectric Layer The dielectric layer in the present disclosure is a member used in the first embodiment of the frequency selective reflector described above.

[0396] The dielectric layer is the same as that described in the above section "A. Frequency selective reflector I. First embodiment 1. Dielectric layer," and therefore a description thereof will be omitted here.

[0397] The present disclosure is not limited to the above-described embodiments. The above-described embodiments are merely examples, and any configuration that is substantially identical to the technical idea described in the claims of the present disclosure and that provides similar effects is included within the technical scope of the present disclosure.

[0398] The present disclosure will be specifically described below with reference to examples.

[0399] Example 1 A simulation of the reflection characteristics of a frequency-selective reflector was performed. In the simulation, a model was used in which the first and second regions of the dielectric layer had thicknesses such that the difference in relative reflection phase between the first and second regions was 180 degrees, and which had the patterns shown in Figures 1(a) and 1(b). In addition, in the simulation, the reflecting member was modeled as having a regularly arranged ring-shaped reflecting element that resonates at the frequency of the incident wave and reflects electromagnetic waves of that frequency. In addition, the following parameters were used in the simulation.

[0400] Frequency of incident wave: 28 GHz Incident angle of incident wave: θ = 63 degrees, φ = 170 degrees Desired reflection angle of reflected wave: θ = 26 degrees, φ = 0 degrees Difference in relative reflection phase between first and second areas: 180 degrees Transmission power: 32 [dBm EIRP] Receiving antenna gain: 0 [dBi] Distance from transmission point to frequency selective reflector: 15 [m] Distance from frequency selective reflector to receiving point: 14 [m] In the simulation, a right-handed coordinate system was used, and the frequency selective reflector was placed at the origin of the coordinate system.

[0401] FIG. 47 shows the results of a simulation using the ray tracing method under the above conditions.

[0402] [Example 2] A simulation of the reflection characteristics of a frequency selective reflector was performed. In the simulation, a model was used in which the dielectric layer had a first dielectric layer and a second dielectric layer, and the first and second regions of the first dielectric layer and the first and second regions of the second dielectric layer had thicknesses such that the difference in relative reflection phase between the region where the first region of the first dielectric layer and the first region of the second dielectric layer overlap and the region where the second region of the first dielectric layer and the first region of the second dielectric layer overlap was 120 degrees, and the difference in relative reflection phase between the region where the first region of the first dielectric layer and the first region of the second dielectric layer overlap and the region where the second region of the first dielectric layer and the second region of the second dielectric layer overlap was 240 degrees, and the model had patterns as shown in Figures 10(a), (b), 11(a), (b), and 12(a). In the simulation, the reflecting member was modeled as having a regularly arranged ring-shaped reflecting element that resonates at the frequency of the incident wave and reflects electromagnetic waves of that frequency. The following parameters were used in the simulation:

[0403] Frequency of incident wave: 28 GHz Incident angle of incident wave: θ = 63 degrees, φ = 170 degrees Desired reflection angle of reflected wave: θ = 26 degrees, φ = 0 degrees Difference in relative reflection phase between the area where the first region of the first dielectric layer and the first region of the second dielectric layer overlap and the area where the second region of the first dielectric layer and the first region of the second dielectric layer overlap: 120 degrees Difference in relative reflection phase between the area where the first region of the first dielectric layer and the first region of the second dielectric layer overlap and the area where the second region of the first dielectric layer and the second region of the second dielectric layer overlap: 240 degrees Transmission power: 32 [dBm EIRP] Receiving antenna gain: 0 [dBi] Distance from transmission point to frequency selective reflector: 15 [m] Distance from frequency selective reflector to receiving point: 14 [m] In the simulation, a right-handed coordinate system was used, and the frequency selective reflector was placed at the origin of the coordinate system.

[0404] FIG. 48 shows the results of a simulation using the ray tracing method under the above conditions.

[0405] [Reference Example 1] A simulation of the reflection characteristics of a frequency selective reflector was performed. In the simulation, a model was used in which the cross-sectional shape of the dielectric layer was stepped and the number of steps was 81. In addition, in the simulation, the model was used in which the reflecting member had ring-shaped reflecting elements regularly arranged, which resonated at the frequency of the incident wave and reflected the electromagnetic wave of that frequency. In addition, the following parameters were used in the simulation.

[0406] Frequency of incident wave: 28 GHz Incident angle of incident wave: θ = 63 degrees, φ = 170 degrees Desired reflection angle of reflected wave: θ = 26 degrees, φ = 0 degrees Difference in relative reflection phase between adjacent stages: approximately 4.4 degrees Transmission power: 32 [dBm EIRP] Receiving antenna gain: 0 [dBi] Distance from transmission point to frequency selective reflector: 15 [m] Distance from frequency selective reflector to receiving point: 14 [m] In the simulation, a right-handed coordinate system was used, and the frequency selective reflector was placed at the origin of the coordinate system.

[0407] FIG. 49 shows the results of a simulation using the ray tracing method under the above conditions.

[0408] Example 3 A simulation of the reflection characteristics of a frequency-selective reflector was performed. In the simulation, the dielectric member had a first dielectric layer and a second dielectric layer in this order from the reflecting member side. For example, as shown in FIG. 21( a), a model was used that had an A1 region 31 that did not have the first dielectric pattern or the second dielectric pattern, an A2 region 32 that had only the first dielectric pattern, and an A3 region 33 that had the first dielectric pattern and the second dielectric pattern. The reflecting member was modeled as having a regularly arranged ring-shaped reflecting element that resonated at the frequency of the incident wave and reflected electromagnetic waves of that frequency. A simulation was performed using a ray tracing method under the following conditions. A right-handed coordinate system was used, and the frequency-selective reflector was placed at the origin of the coordinate system. The results are shown in FIG. 50.

[0409] Frequency of incident wave: 28 GHz Incident angle of incident wave: θ = 63 degrees, φ = 170 degrees Desired reflection angle of reflected wave: θ = 26 degrees, φ = 0 degrees Difference in relative reflection phase of electromagnetic wave between A1 area 31 and A2 area 32: 120 degrees Difference in relative reflection phase of electromagnetic wave between A1 area 31 and A3 area 33: 240 degrees Transmission power: 32 [dBm EIRP] Receiving antenna gain: 0 [dBi] Distance from transmission point to frequency selective reflector: 15 [m] Distance from frequency selective reflector to receiving point: 14 [m]

[0410] Reference Example 2 Controlling the reflection direction of electromagnetic waves by controlling the relative reflection phase distribution of electromagnetic waves through the thickness distribution of a dielectric member will be described with reference to reference examples 2 and 3.

[0411] A simulation of the reflection characteristics of a frequency-selective reflector was performed. In the simulation, the unit structure of the dielectric member had a thickness distribution in which the thickness increased in one direction, as shown in Figure 51(a), and had six cell regions of different thicknesses. The dielectric member was modeled to have a periodic structure in which the unit structures were repeatedly arranged in one direction. In addition, in the simulation, the reflecting member was modeled to have ring-shaped reflecting elements regularly arranged, which resonated at the frequency of the incident wave and reflected electromagnetic waves of that frequency. In addition, the following parameters were used in the simulation.

[0412] Frequency of incident wave: 28 GHz Incident angle of incident wave: 0 degrees, -10 degrees Desired reflection angle of reflected wave: 27 degrees, 37 degrees Relative reflection phase difference between adjacent cell areas: 60 degrees

[0413] The simulation results are shown in Figure 51(b). When the incident angle is 0 degrees, that is, when incident from the front direction 201, the reflection is shown by the solid line designated by the reference symbol 202, and when the incident angle is -10 degrees, that is, when incident from the -10 degree direction 203, the reflection is shown by the solid line designated by the reference symbol 204. It can be seen that when the incident angle is 0 degrees, reflection occurs in the +27 degree direction from the specular reflection direction, and when the incident angle is -10 degrees, reflection occurs in the +37 degree direction from the specular reflection direction.

[0414] [Reference Example 3] First, a reflective member in which ring-shaped reflective elements were regularly arranged was produced by etching a PET film with copper foil, in accordance with the model of the reflective member of Reference Example 2. Furthermore, a dielectric member was formed using a 3D printer in accordance with the model of the dielectric member of Reference Example 2. Next, a frequency-selective reflector was produced by attaching the dielectric member onto the reflective member.

[0415] The reflection characteristics of the frequency selective reflector were measured using a compact range measurement system and a network analyzer. The reflection characteristics of the frequency selective reflector of Reference Example 3 were almost identical to the simulation results of Reference Example 2.

[0416] [Reference Example 4] In an analysis of a reflectarray, the reflection phase was calculated for a frequency selective reflector having a reflecting member with a frequency selective surface (FSS) and a dielectric layer using a general transmission line equivalent circuit as shown in Figure 52. Note that the symbols in Figure 52 are as follows: ZVAC: Indicates a transmission line with the characteristic impedance of air. The line length is the length obtained by subtracting the thickness of the dielectric layer from the phase observation plane set at an arbitrary distance away from the top surface of the dielectric layer. ZPC: Indicates a transmission line with the characteristic impedance of the dielectric layer. The line length is the thickness of the dielectric layer. r: Indicates the resistance of the FSS ring-shaped reflecting element. L: Indicates the inductance of the FSS ring-shaped reflecting element. C: Indicates the capacitance of the FSS ring-shaped reflecting element. ZPET: Indicates a transmission line with the dielectric constant of the dielectric substrate on which the FSS ring-shaped reflecting element is arranged. The line length is the thickness of the dielectric substrate. ZL: Indicates the characteristic impedance of the space (air) on the back surface of the dielectric substrate.

[0417] As a result, it was calculated that the reflection phase change due to the resonance frequency shift caused by stacking dielectric layers of different thicknesses is at most several tens of degrees, which is about 25% of the maximum reflection phase of 360 degrees, and that the remaining reflection phase change is due to wavelength shortening within the dielectric layers. Furthermore, even if the positions of the reflective member having a frequency selective surface and the dielectric layer are misaligned, the misalignment will be uniform throughout the frequency selective reflector, but considering that the reflection phase with adjacent areas only needs to be uniform in order for the reflected wave to be a plane wave, it was concluded that there is almost no effect on the reflection direction.

[0418] The present disclosure provides the following inventions. [1] A frequency selective reflector that reflects electromagnetic waves in a specific frequency band of 24 GHz or more in a direction different from a specular reflection direction, comprising: a reflecting member that reflects the electromagnetic waves; and a dielectric layer that is arranged on the electromagnetic wave incident side of the reflecting member and transmits the electromagnetic waves, the dielectric layer having two thicknesses, and having a plurality of first regions with a small thickness and a plurality of second regions with a large thickness. [2] The frequency selective reflector according to [1], wherein the thickness of the first regions is zero. [3] The frequency selective reflector according to [1] or [2], wherein the reflecting member is a frequency selective plate that reflects only the electromagnetic waves. [4] The frequency selective reflector according to [3], wherein the reflecting member has a reflection phase control function that controls the reflection phase of the electromagnetic waves. [5] The frequency selective reflector according to any one of [1] to [4], wherein the absolute value of the difference between the relative reflection phase of the electromagnetic wave in the first region and the relative reflection phase of the electromagnetic wave in the second region is greater than 0 degrees and less than 360 degrees. [6] The frequency selective reflector according to any one of [1] to [5], wherein the dielectric layer contains a resin. [7] The frequency selective reflector according to [6], wherein the dielectric layer contains a filler. [8] The frequency selective reflector according to any one of [1] to [7], wherein the frequency selective reflector has a ground layer on the surface of the reflecting member opposite to the dielectric layer, or wherein the reflecting member has a reflecting layer that also serves as a ground layer. [9] The frequency selective reflector according to any one of [1] to [8], wherein an adhesive layer is provided between the reflecting member and the dielectric layer.

[10] The frequency selective reflector according to any one of [1] to [8], wherein a space is provided between the reflecting member and the dielectric layer.

[11] The frequency selective reflector according to any one of [1] to

[10] , which has a cover member on the surface of the dielectric layer opposite to the reflecting member.

[12] The frequency selective reflector according to any one of [1] to

[11] , in which the frequency of the electromagnetic wave is 300 GHz or less.

[13] The frequency selective reflector according to any one of [1] to

[12] , in which the dielectric layer has a support portion that supports the second region.

[0419]

[14] A frequency selective reflector that reflects electromagnetic waves of a specific frequency band in a direction different from the specular reflection direction, comprising: a substrate; a reflecting member that is arranged on one surface of the substrate and reflects the electromagnetic waves; and a dielectric member that is arranged on the surface of the reflecting member opposite the substrate and transmits the electromagnetic waves, wherein the dielectric member has, from the reflecting member side, a first dielectric layer and a second dielectric layer, in this order, the first dielectric layer has a plurality of first dielectric portions arranged on the surface of the reflecting member opposite the substrate, the second dielectric layer has a plurality of second dielectric portions arranged on the surface of the first dielectric layer opposite the reflecting member, the second dielectric portions are arranged so as to overlap the boundaries of adjacent first dielectric portions in a planar view, the first dielectric portion has a first dielectric pattern, and the second dielectric portion has a second dielectric pattern.

[15] The frequency selective reflector according to

[14] , wherein the dielectric member has, from the reflecting member side, an A1 region not having the first dielectric pattern or the second dielectric pattern, an A2 region from the reflecting member side having only the first dielectric pattern, and an A3 region from the reflecting member side having the first dielectric pattern and the second dielectric pattern.

[16] The frequency selective reflector according to

[14] or

[15] , wherein, in a plan view, the distance between the boundary between adjacent first dielectric portions and the boundary between adjacent second dielectric portions is ⅓ or more of the thickness of the dielectric member.

[17] The frequency selective reflector according to any of

[14] to

[16] , wherein the substrate has an alignment mark.

[18] The frequency selective reflector according to any of

[14] to

[17] , wherein the first dielectric portion and the second dielectric portion have alignment marks.

[19] The frequency selective reflector according to any one of

[14] to

[18] , wherein the first dielectric portion has a first support portion that supports the first dielectric pattern, and the second dielectric portion has a second support portion that supports the second dielectric pattern.

[20] The frequency selective reflector according to

[19] , wherein the first dielectric portion and the second dielectric portion are arranged so that the first support portion and the second support portion overlap in a plan view.

[21] The frequency selective reflector according to any one of

[14] to

[20] , wherein the first dielectric portion and the second dielectric portion are fixed by a pin penetrating the first dielectric portion and the second dielectric portion.

[22] The frequency selective reflector according to any one of

[14] to

[20] , wherein the first dielectric layer and the second dielectric layer are bonded to each other.

[23] The dielectric member has, from the reflecting member side, the first dielectric layer, the second dielectric layer, and the third dielectric layer in this order, the third dielectric layer has a plurality of third dielectric portions arranged on a surface of the second dielectric layer opposite to the first dielectric layer, the third dielectric portions having a third dielectric pattern, and the dielectric member has, from the reflecting member side, a B1 region not having the first dielectric pattern, the second dielectric pattern, and the third dielectric pattern, a B2 region from the reflecting member side having only the first dielectric pattern, a B3 region from the reflecting member side having only the first dielectric pattern and the second dielectric pattern, and a B4 region from the reflecting member side having the first dielectric pattern, the second dielectric pattern, and the third dielectric pattern, or the dielectric member has, from the reflecting member side, a third dielectric layer, the first dielectric layer, and the second dielectric layer in this order, the third dielectric layer has a plurality of third dielectric portions arranged on a surface of the reflecting member opposite to the base material, the third dielectric portions having a third dielectric pattern, and the dielectric member has, from the reflecting member side, a C1 region not having the third dielectric pattern, the first dielectric pattern, and the second dielectric pattern, a C2 region from the reflecting member side having only the third dielectric pattern, a C3 region from the reflecting member side having only the third dielectric pattern and the first dielectric pattern, and a C4 region from the reflecting member side having the third dielectric pattern, the first dielectric pattern, and the second dielectric pattern, or

[14] or any one of

[16] to

[22] , wherein the dielectric member has, from the reflecting member side, the first dielectric layer, the third dielectric layer, and the second dielectric layer in this order, the third dielectric layer has a plurality of third dielectric portions arranged on a surface of the first dielectric layer opposite the reflecting member, the third dielectric portions having a third dielectric pattern, and the dielectric member has, from the reflecting member side, a D1 region not having the first dielectric pattern, the third dielectric pattern, and the second dielectric pattern, a D2 region from the reflecting member side having only the first dielectric pattern, a D3 region from the reflecting member side having only the first dielectric pattern and the third dielectric pattern, and a D4 region from the reflecting member side having the first dielectric pattern, the third dielectric pattern, and the second dielectric pattern.

[24] The frequency selective reflector according to

[23] , wherein the third dielectric portion is arranged so as to overlap the boundary between adjacent first dielectric portions and the boundary between adjacent second dielectric portions in a plan view.

[25] The frequency selective reflector according to any one of

[14] to

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

[26] The frequency selective reflector according to

[25] , wherein the reflecting member has a plurality of types of reflecting elements with different sizes.

[0420] REFERENCE SIGNS LIST 1 ... frequency selective reflector 2 ... reflecting member 3 ... reflecting element 4 ... dielectric substrate 5 ... dielectric member 6 ... adhesive member 7 ... reflecting layer 8 ... space 11 ... first dielectric layer 11a, 11b ... first dielectric portion 11P ... first dielectric pattern 11S ... first support portion 11X ... boundary between adjacent first dielectric portions 12 ... second dielectric layer 12a, 12b, 12c ... second dielectric portion 12P ... second dielectric pattern 12S ... second support portion 12X ... boundary between adjacent second dielectric portions 16a, 16b ... adhesive layer 17 ... pin 31 ... A1 region 32 ... A2 region 33 ... A3 region 305 ... dielectric layer 306 ... adhesive layer 309 ... support portion 311 ... first region of dielectric layer 312 ... second region of dielectric layer D1 ...predetermined direction t31 ...thickness of the first region of the dielectric layer t32 ...thickness of the second region of the dielectric layer

Claims

1. A frequency selective reflector that reflects electromagnetic waves of a specific frequency band in a direction different from the regular reflection direction, A reflecting member that reflects the electromagnetic wave; a dielectric layer that is disposed on an incident side of the electromagnetic wave with respect to the reflecting member and transmits the electromagnetic wave; The dielectric layer has two thicknesses, and has a plurality of first regions having a small thickness and a plurality of second regions having a large thickness.

2. 2. The frequency selective reflector of claim 1, wherein the first region has a thickness of zero.

3. 3. The frequency selective reflector according to claim 1, wherein the reflecting member is a frequency selective plate that reflects only the electromagnetic wave.

4. 4. The frequency selective reflector according to claim 3, wherein the reflecting member has a plurality of types of reflecting elements having different sizes.

5. 3. A frequency selective reflector according to claim 1, wherein an absolute value of a difference between a relative reflection phase of the electromagnetic wave in the first region and a relative reflection phase of the electromagnetic wave in the second region is greater than 0 degrees and less than 360 degrees.

6. 3. The frequency selective reflector according to claim 1, wherein the dielectric layer contains a resin.

7. 7. The frequency selective reflector of claim 6, wherein the dielectric layer contains a filler.

8. 3. A frequency selective reflector as described in claim 1 or claim 2, wherein the frequency selective reflector has a ground layer on a surface of the reflecting member opposite the dielectric layer, or the reflecting member has a reflecting layer that also serves as a ground layer.

9. 3. The frequency selective reflector according to claim 1, further comprising an adhesive layer between the reflecting member and the dielectric layer.

10. 3. The frequency selective reflector according to claim 1, further comprising a space between the reflecting member and the dielectric layer.

11. 3. The frequency selective reflector according to claim 1, further comprising a cover member on a surface of said dielectric layer opposite to said reflecting member.

12. 3. The frequency selective reflector according to claim 1, wherein the electromagnetic wave has a frequency of 300 GHz or less.

13. 3. The frequency selective reflector according to claim 1, wherein the dielectric layer has a support portion that supports the second region.

14. A frequency selective reflector that reflects electromagnetic waves of a specific frequency band in a direction different from the regular reflection direction, A substrate; A reflecting member disposed on one surface of the base material and reflecting the electromagnetic wave; a dielectric member that is disposed on a surface of the reflecting member opposite to the base material and transmits the electromagnetic wave; the dielectric member has, from the reflecting member side, a first dielectric layer and a second dielectric layer in this order, the first dielectric layer has a plurality of first dielectric portions arranged on a surface of the reflecting member opposite to the base material, the second dielectric layer has a plurality of second dielectric portions arranged on a surface of the first dielectric layer opposite to the reflecting member, the second dielectric portion is disposed so as to overlap a boundary between adjacent first dielectric portions in a plan view, A frequency selective reflector, wherein the first dielectric portion has a first dielectric pattern, and the second dielectric portion has a second dielectric pattern.

15. The frequency selective reflector of claim 14, wherein the dielectric member has an A1 region that does not have the first dielectric pattern and the second dielectric pattern from the reflecting member side, an A2 region that has only the first dielectric pattern from the reflecting member side, and an A3 region that has the first dielectric pattern and the second dielectric pattern from the reflecting member side.

16. 16. A frequency selective reflector according to claim 14 or 15, wherein in a planar view, the distance between a boundary between adjacent first dielectric portions and a boundary between adjacent second dielectric portions is 1 / 3 or more of the thickness of the dielectric member.

17. 16. The frequency selective reflector according to claim 14 or 15, wherein the substrate has alignment marks.

18. 16. The frequency selective reflector according to claim 14 or 15, wherein the first dielectric portion and the second dielectric portion have alignment marks.

19. 16. A frequency selective reflector as described in claim 14 or claim 15, wherein the first dielectric portion has a first support portion that supports the first dielectric pattern, and the second dielectric portion has a second support portion that supports the second dielectric pattern.

20. 20. The frequency selective reflector according to claim 19, wherein the first dielectric portion and the second dielectric portion are arranged such that the first support portion and the second support portion overlap in a plan view.

21. 16. The frequency selective reflector according to claim 14, wherein the first dielectric portion and the second dielectric portion are fixed by a pin that penetrates the first dielectric portion and the second dielectric portion.

22. 16. The frequency selective reflector according to claim 14 or 15, wherein the first dielectric layer and the second dielectric layer are bonded together.

23. the dielectric member has, from the reflecting member side, the first dielectric layer, the second dielectric layer, and a third dielectric layer in this order, the third dielectric layer has a plurality of third dielectric portions arranged on a surface of the second dielectric layer opposite to the first dielectric layer, the third dielectric portions having a third dielectric pattern, the dielectric member has, from the reflecting member side, a B1 region not having the first dielectric pattern, the second dielectric pattern, and the third dielectric pattern, a B2 region having only the first dielectric pattern from the reflecting member side, a B3 region having only the first dielectric pattern and the second dielectric pattern from the reflecting member side, and a B4 region having the first dielectric pattern, the second dielectric pattern, and the third dielectric pattern from the reflecting member side, or the dielectric member has, from the reflecting member side, a third dielectric layer, the first dielectric layer, and the second dielectric layer in this order, the third dielectric layer has a plurality of third dielectric portions arranged on a surface of the reflecting member opposite to the base material, the third dielectric portions having a third dielectric pattern, the dielectric member has, from the reflecting member side, a C1 region not having the third dielectric pattern, the first dielectric pattern, and the second dielectric pattern, a C2 region having only the third dielectric pattern from the reflecting member side, a C3 region having only the third dielectric pattern and the first dielectric pattern from the reflecting member side, and a C4 region having the third dielectric pattern, the first dielectric pattern, and the second dielectric pattern from the reflecting member side, or 15. The frequency selective reflector according to claim 14, wherein the dielectric member has, from the reflecting member side, the first dielectric layer, the third dielectric layer, and the second dielectric layer in this order, the third dielectric layer has a plurality of third dielectric portions arranged on a surface of the first dielectric layer opposite the reflecting member, the third dielectric portions having a third dielectric pattern, and the dielectric member has, from the reflecting member side, a D1 region not having the first dielectric pattern, the third dielectric pattern, and the second dielectric pattern, a D2 region having only the first dielectric pattern from the reflecting member side, a D3 region having only the first dielectric pattern and the third dielectric pattern from the reflecting member side, and a D4 region having the first dielectric pattern, the third dielectric pattern, and the second dielectric pattern from the reflecting member side.

24. 24. The frequency selective reflector according to claim 23, wherein the third dielectric portion is arranged so as to overlap a boundary between adjacent first dielectric portions and to overlap a boundary between adjacent second dielectric portions in a plan view.

25. 16. The frequency selective reflector according to claim 14, wherein the reflecting member is a frequency selective plate that reflects only the electromagnetic wave.

26. 26. The frequency selective reflector according to claim 25, wherein the reflecting member has a plurality of types of reflecting elements having different sizes.

27. 3. The frequency selective reflector according to claim 1 or 2, wherein the frequency band of the electromagnetic waves is a frequency band used in a fifth generation mobile communication system (5G).

28. 3. The frequency selective reflector according to claim 1, wherein the frequency band of the electromagnetic waves is 24 GHz or higher.