Electromagnetic wave reflection panel, electromagnetic wave reflection device, and electromagnetic wave reflection fence

Abstract

Provided is an electromagnetic wave reflection panel that reflects both horizontally polarized waves and vertically polarized waves in a controlled direction.　The electromagnetic wave reflection panel includes a dielectric layer, a conductive pattern provided on one surface of the dielectric layer, and a ground layer provided on the other surface of the dielectric layer. The conductive pattern is formed of a periodic array of square hollow patterns, reflects electromagnetic waves in a predetermined band selected from 1 MHz to 300 GHz inclusive, and has a projecting portion projecting outward from at least a part of a corner portion of the hollow pattern.

Description

Electromagnetic wave reflecting panel, electromagnetic wave reflecting device, and electromagnetic wave reflecting fence

[0001] The present disclosure relates to an electromagnetic wave reflecting panel, an electromagnetic wave reflecting device, and an electromagnetic wave reflecting fence.

[0002] While the fifth-generation (hereinafter referred to as "5G") mobile communication standard promises high-speed, high-capacity communications, it uses radio waves with strong directionality, which can create areas where radio waves are difficult to reach. In places with many metal machines, such as factories, or in urban areas with many reflections from walls and street trees, a means is needed to deliver radio waves to the desired terminal devices and wireless devices. Similar requirements exist in places where non-line-of-sight (NLOS) spots occur, such as medical settings, event venues, and large commercial facilities. The next-generation sixth-generation standard is also expected to use the terahertz or sub-terahertz band, and similar requirements exist.

[0003] In recent years, artificial reflective surfaces known as "metasurfaces" have been developed. Metasurfaces are formed with periodic structures or patterns that are smaller than the wavelength and are designed to reflect radio waves in a desired direction (see, for example, Non-Patent Document 1). Because metasurfaces can achieve a desired reflection angle while maintaining a planar configuration, they function effectively as reflectors even in environments where there is not enough space to install multiple electromagnetic wave reflection panels. Configurations have been proposed in which electromagnetic wave reflection devices with metasurfaces or regular reflection surfaces are introduced into production lines in factories and plants (see, for example, Patent Documents 1 and 2).

[0004] International Publication No. 2021 / 199503 International Publication No. 2021 / 199504

[0005] Diaz-Rubio et al., Sci. Adv. 2017: 3: e1602714 1

[0006] Metasurfaces are often formed by a periodic arrangement of rectangular metal patterns. Reflectors with such patterns respond to waves polarized parallel to the long sides of the metal patterns but not to waves polarized perpendicular to the long sides. Some 5G antennas support only horizontal or vertical polarization, while others support both horizontal and vertical polarization. Known metasurface design patterns have difficulty achieving the desired reflection characteristics for both polarizations.

[0007] An object of the present disclosure is to provide an electromagnetic wave reflective panel that reflects both horizontally and vertically polarized waves in controlled directions.

[0008] In one embodiment, the electromagnetic wave reflecting panel includes a dielectric layer, a conductive pattern provided on one side of the dielectric layer, and a ground layer provided on the other side of the dielectric layer, wherein the conductive pattern is formed of a periodic arrangement of rectangular hollow patterns, reflects electromagnetic waves in a predetermined band selected from 1 MHz to 300 GHz, and has protrusions that protrude outward from at least a portion of the corners of the hollow patterns.

[0009] An electromagnetic wave reflective panel is realized that reflects both horizontally and vertically polarized waves in controlled directions.

[0010] FIG. 7 is a schematic diagram of an electromagnetic wave reflecting device using an electromagnetic wave reflecting panel of an embodiment. FIG. 8 is a schematic diagram of an electromagnetic wave reflecting fence in which a plurality of electromagnetic wave reflecting devices are connected. FIG. 9 is a diagram showing an example of the layer structure of an electromagnetic wave reflecting panel. FIG. 10 is a diagram showing another example of the layer structure of an electromagnetic wave reflecting panel. FIG. 11 is a diagram showing an example of a unit cell constituting a periodic conductive pattern. FIG. 12 is a diagram showing another example of a unit cell constituting a periodic conductive pattern. FIG. 13 is a diagram showing another example of a unit cell constituting a periodic conductive pattern. FIG. 14 is a diagram showing a model of a conductive pattern used to evaluate reflection characteristics. FIG. 15 is a perspective view of the analysis space of the model of FIG. 6. FIG. 16 is a schematic diagram of the XZ plane of the analysis space.

[0011] In this embodiment, in order to accommodate both horizontally and vertically polarized waves, the conductive pattern constituting the reflective surface is formed as a periodic arrangement of hollow patterns formed on the periphery (outer edge) of a rectangle. By forming the hollow pattern into a rectangular shape, current flows in two orthogonal directions along the periphery. The hollow pattern has protrusions that protrude outward from at least some of the corners. This allows both horizontally and vertically polarized waves to be reflected in controlled directions.

[0012] Below, an electromagnetic wave reflective panel according to an embodiment, and an electromagnetic wave reflective device and an electromagnetic wave reflective fence using the same will be described with reference to the drawings. The embodiments described below are examples intended to embody the technical concepts of the disclosure and are not intended to limit the present disclosure to the following processes and numerical values. In the drawings, components having the same function may be assigned the same reference numerals to avoid redundant description. Partial substitution or combination between different embodiments and configuration examples is possible. The size, positional relationship, etc. of each component shown in each drawing may be exaggerated to facilitate understanding of the disclosure. When referring to a positional relationship, "above" or "below" refers to the top or bottom of the stacking direction or film formation direction, unless otherwise specified, and is not an absolute direction.

[0013] Fig. 1 is a schematic diagram of an electromagnetic wave reflecting device 60 using an electromagnetic wave reflecting panel 10 according to an embodiment. The electromagnetic wave reflecting device 60 includes the electromagnetic wave reflecting panel 10 and a frame 50 that holds the electromagnetic wave reflecting panel 10. In the coordinate system of Fig. 1, when the electromagnetic wave reflecting device 60 is installed, the width or lateral direction of the electromagnetic wave reflecting panel 10 is defined as the X direction, the height or longitudinal direction is defined as the Y direction, and the thickness direction is defined as the Z direction. The electromagnetic wave reflecting panel 10 reflects electromagnetic waves in the gigahertz to terahertz bands, such as microwaves, millimeter waves, and submillimeter waves, and reflects electromagnetic waves of, for example, 1 MHz to 300 GHz.

[0014] The electromagnetic wave reflecting panel 10 has, at least in part, a metasurface with a controlled reflection direction. Conversely, the electromagnetic wave reflecting panel 10 may have, in part, a specular reflection surface where the incident angle and exit angle of the electromagnetic wave are equal. The metasurface may not only provide a non-specular reflection surface that reflects the incident electromagnetic wave in a direction different from the incident angle, but may also be designed to control the diffusion state of the electromagnetic wave.

[0015] The metasurface of the electromagnetic wave reflecting panel 10 reflects both horizontally polarized waves and vertically polarized waves in controlled directions. Horizontally polarized waves are waves that vibrate parallel to the ground or transversely to the propagation direction. Vertically polarized waves are waves that vibrate perpendicular to the ground or longitudinally to the propagation direction. By forming the conductor pattern that makes up the metasurface as a hollow rectangle, both horizontally polarized waves and vertically polarized waves can be reflected in controlled directions. A hollow rectangular conductor pattern means that the conductor pattern is rectangular and annular.

[0016] The frame 50 supports two sides of the electromagnetic wave reflecting panel 10 along the height direction when the panel is installed. In addition to the frame 50, a top frame 57 that supports the upper end of the electromagnetic wave reflecting panel 10 and a bottom frame 58 that supports the lower end may be provided. In this case, the frame 50, the top frame 57, and the bottom frame 58 constitute a frame that supports the entire periphery of the electromagnetic wave reflecting panel 10. The frame 50 may be referred to as a "side frame" based on its position relative to the top frame 57 and the bottom frame 58. Legs 56 that support the frame 50 may be provided. As shown in FIG. 1 , providing the legs 56 is desirable when the electromagnetic wave reflecting device 60 is to be freestanding on an installation surface, but the legs 56 are not required. The legs 56 may be provided with casters to make the panel mobile, or the electromagnetic wave reflecting panel 10 may be installed on a wall or hung from a ceiling without the legs 56.

[0017] Fig. 2 is a schematic diagram of an electromagnetic wave reflecting fence 100 in which electromagnetic wave reflecting devices 60-1, 60-2, and 60-3 are connected together. In Fig. 2, three electromagnetic wave reflecting devices 60-1, 60-2, and 60-3 (hereinafter, sometimes collectively referred to as "electromagnetic wave reflecting devices 60") are connected together to form the electromagnetic wave reflecting fence 100, but there is no particular limit to the number of electromagnetic wave reflecting devices 60 that can be connected together.

[0018] The electromagnetic wave reflecting devices 60-1, 60-2, and 60-3 each have an electromagnetic wave reflecting panel 10-1, 10-2, and 10-3, respectively. Adjacent electromagnetic wave reflecting panels are held together by a frame 50, resulting in an electromagnetic wave reflecting fence 100 connected in the X direction. Each of the electromagnetic wave reflecting panels 10-1, 10-2, and 10-3 (hereinafter sometimes collectively referred to as the "electromagnetic wave reflecting panel 10") has, at least in part, a reflecting surface formed by a hollow rectangular conductive pattern. This allows both horizontally polarized waves and vertically polarized waves to be reflected in controlled directions.

[0019] <Layer Structure of Electromagnetic Wave Reflecting Panel> Figure 3 shows the layer structure of the electromagnetic wave reflecting panel 10A. This layer structure is the layer structure at the A-A cross section of Figure 1, and the stacking direction is the thickness direction (Y direction) of the electromagnetic wave reflecting panel 10A. The electromagnetic wave reflecting panel 10A has a dielectric layer 11, a periodic conductive pattern 15 provided on one surface 111 of the dielectric layer 11, and a ground layer 12 provided on the other surface 112 of the dielectric layer 11. The conductive pattern 15 forms the reflective surface of the electromagnetic wave reflecting panel 10A and reflects electromagnetic waves in the frequency range of 1 MHz to 300 GHz in a predetermined direction.

[0020] The conductive pattern 15 includes a periodic arrangement of a plurality of hollow patterns 151. The specific shape of the hollow patterns 151 will be described later with reference to FIGS. 5A to 5D. The hollow patterns are formed of a good conductor such as Ag, Cu, Ni, or Al, and have a thickness of 0.01 mm or more and 0.05 mm or less. If the thickness is less than 0.01 mm, the surface resistivity becomes high, making it difficult to maintain high reflection efficiency. If the thickness is greater than 0.05 mm, it becomes difficult to maintain the flatness of the reflection surface. The surface of the conductive pattern 15 may be protected with a transparent film having a dielectric constant and dielectric loss tangent equivalent to those of the dielectric layer 11.

[0021] The hollow pattern 151 is bonded to the dielectric layer 11 by an adhesive layer 13. The adhesive layer 13 is not applied to the entire surface of the dielectric layer 11, but is applied in an amount necessary to stably support the hollow pattern 151. This is to minimize the effect of the adhesive layer 13 on the dielectric constant of the dielectric layer 11. The area occupied by the adhesive layer 13 does not need to be exactly the same as the area occupied by the conductive pattern 15; there may be some deviation as long as the hollow pattern 151 can be stably bonded to the dielectric layer 11. For example, if the area occupancy of the conductive pattern 15 with respect to the dielectric layer 11 is 10.0% or more and 45.0% or less, the area occupancy of the adhesive layer 13 with respect to the dielectric layer 11 is 9.0% or more and 50.0% or less.

[0022] If the area occupation ratio of the conductive pattern 15 is less than 10.0%, it becomes difficult to achieve the desired reflection characteristics and reflection efficiency. If the area occupation ratio of the conductive pattern 15 exceeds 45.0%, it becomes difficult to maintain the transparency of the electromagnetic wave reflecting panel 10A. However, in applications that do not require transparency, the area occupation ratio of the conductive pattern 15 may be set to more than 45.0% to prioritize reflection efficiency.

[0023] The adhesive layer 13 is made of a material capable of bonding the conductive pattern 15 to the dielectric layer 11, and may be made of a thermoplastic resin such as vinyl acetate resin, acrylic resin, cellulose resin, or silicone resin. The thickness of the adhesive layer 13 is such that the conductive pattern 15 can be stably bonded to the dielectric layer 11, and is, for example, 0.002 mm or more and 0.050 mm or less. From the viewpoint of ensuring adhesive strength, the thickness is desirably 0.010 mm or more and 0.050 mm or less.

[0024] The dielectric layer 11 is an insulating polymer film made of polycarbonate, cycloolefin polymer (COP), polyethylene terephthalate (PET), fluororesin, or the like, and has a thickness of about 0.3 mm to 1.0 mm. The dielectric layer 11 may be made of any material having a relative permittivity and dielectric loss tangent suitable for achieving the target reflection characteristics.

[0025] The ground plane 12 may be made of the same material as the conductive pattern 15, or may be made of a different conductive material. The ground plane 12 forms a predetermined capacitance between the conductive pattern 15. The capacitance formed between the conductive pattern 15 and the ground plane 12 determines the magnitude of the phase delay.

[0026] FIG. 4 shows the layer structure of the electromagnetic wave reflecting panel 10B. This layer structure has the layer structure of FIG. 3 sandwiched between two dielectric substrates 21 and 22. The dielectric substrate 21 is bonded to the ground layer 12 by an adhesive layer 23. The dielectric substrate 22 is bonded to the conductive pattern 15 side of the dielectric layer 11 by an adhesive layer 24. The dielectric substrates 21 and 22 are transparent to electromagnetic waves in the gigahertz to terahertz bands, specifically, electromagnetic waves in the range of 1 MHz to 3 THz, for example, 1 MHz to 300 GHz. The dielectric substrates 21 and 22 are preferably formed as the outermost layers of the electromagnetic wave reflecting panel 10B from a material with excellent impact resistance, durability, and transparency. The dielectric substrates 21 and 22 can be made of polycarbonate, acrylic resin, PET, or the like. The thickness of the dielectric substrates 21 and 22 can be selected appropriately depending on the installation location, for example, between 1.0 mm and 10.0 mm. The dielectric substrates 21 and 22 may have the same thickness or different thicknesses.

[0027] The adhesive layer 23 protects the surface of the ground layer 12 and adhesively holds the dielectric substrate 21. The adhesive layer 24 protects the surface of the conductive pattern 15 and adhesively holds the dielectric substrate 22. The adhesive layers 23 and 24 are preferably durable and moisture-resistant, and may be made of, for example, ethylene-vinyl acetate (EVA) copolymer or cycloolefin polymer (COP). The thickness of the adhesive layers 23 and 24 is appropriately determined within a range of 10 μm to 400 μm so as to be able to bond the dielectric substrates 21 and 22.

[0028] By covering the conductive pattern 15 with the adhesive layer 24 and bonding the dielectric substrate 22, the intrusion of moisture and air into the surface of the conductive pattern 15 is suppressed, and deterioration of the reflective surface is suppressed. By covering the ground layer 12 with the adhesive layer 23 and bonding the dielectric substrate 21, the intrusion of moisture and air into the surface of the ground layer 12 is suppressed, and surface deterioration of the ground layer 12 is suppressed. This keeps the capacitance between the ground layer 12 and the conductive pattern 15 constant, and the designed magnitude of phase delay can be maintained. In other words, the reflection efficiency of radio waves in the designed direction can be maintained.

[0029] <Configuration Example of Hollow Pattern> Figure 5A shows an example of a unit cell 20 of a conductive pattern 15 composed of hollow patterns 151. In this example, the unit cell 20 is formed by six hollow patterns 151a, 151b, 151c, 151d, 151e, and 151f. The width W1 and length L of the hollow patterns 151a to 151f correspond to the width (X) and height (Z) directions of the electromagnetic wave reflecting panel 10 in Figure 1, respectively. The length W1 is the length in the direction in which the short side of the hollow pattern 151 extends, and the length L is the length in the direction in which the long side of the hollow pattern 151 extends. The hollow patterns 151a to 151f have the same width W1 and different lengths L, but their central axes of length are aligned (the Z coordinate position of the central axis is constant). The pitch or spacing G in the X direction is constant. The shape and size of the hollow patterns 151 a to 151 f control the phase of the reflection, and the reflected waves are superimposed to form a reflected beam in a desired direction. In this example, the unit cell 20 is designed to reflect a beam of reflected waves of an electromagnetic wave incident normally (incident angle 0°) in a direction 50° from the normal.

[0030] Each of the hollow patterns 151a, 151b, 151c, 151d, 151e, and 151f (hereinafter, sometimes collectively referred to as "hollow patterns 151") has a hollow with a width W2. That is, the hollow pattern 151 has a rectangular ring shape. More specifically, the quadrangular hollow pattern 151 is a rectangular ring having two horizontally extending portions (an example of a first extending portion) extending in a first direction (X direction) in a plan view and two vertically extending portions (an example of a second extending portion) extending in a second direction (Z direction) in a plan view. The width of the vertical line segment is half the difference between the width W1 of the outer periphery (outer edge) of each hollow pattern 151 and the width W2 of the inner periphery (inner edge). Similarly, the thickness of the horizontal line segment of the hollow pattern 151 is determined depending on the area of ​​the hollow. The vertical and horizontal line segments of hollow pattern 151 enable it to respond to both vertically polarized waves and horizontally polarized waves.

[0031] The hollow pattern 151 has protrusions 151P that protrude outward from the corners of the periphery. For example, the protrusions 151P protrude outward in the X direction from four corners of each hollow pattern 151. The length of the protrusions 151P in the X direction, expressed using the length L as an example, is not less than L / 200 and not more than L / 2.

[0032] Furthermore, the corners on the inner periphery of hollow pattern 151 are rounded with a radius of curvature R. When the corners on the inner periphery (inner edge) are right angles, the radius of curvature R = 0.0 mm. Curving the corners on the inner periphery of hollow pattern 151 with a predetermined radius of curvature R prevents current concentration and maintains reflection efficiency. Specifically, by rounding the corners on the inner periphery of hollow pattern 151 with a radius of curvature R that is between 1 / 10 and 1 / 2 of the width W1 of the inner periphery, i.e., the hollow, it is possible to suppress current concentration while enabling response to both vertically polarized waves and horizontally polarized waves.

[0033] The conductive pattern 15 is a periodic pattern in which unit cells 20 are repeatedly arranged in the X and Y directions. By providing a reflective surface formed by the conductive pattern 15 on at least a part of the electromagnetic wave reflective panel 10, it becomes possible to reflect both horizontally polarized waves and vertically polarized waves of incident electromagnetic waves in controlled directions.

[0034] 5B, 5C, and 5D show another example of a unit cell 20 of a conductive pattern 15 formed of a hollow pattern 151. FIG.

[0035] 5B, the hollow patterns 151 (151a to 151f) may have protrusions 151P that protrude outward in the Z direction from the corners of the outer periphery. As an example, the length of the protrusions 151P in the Z direction is L / 200 or more and L / 2 or less.

[0036] Also, as shown in FIG. 5C, the hollow pattern 151 (151a to 151f) may have a protrusion 151P that protrudes outward in the X direction from the corner of the outer periphery, and the corner of the inner periphery (inner edge) may be a right angle.

[0037] 5D, the hollow patterns 151 (151a to 151f) may have protrusions 151P that protrude outward in the X and Z directions from corners of the periphery. The length of the protrusions 151P protruding in the X direction, expressed as an example using the length L, is L / 200 or more and L / 2 or less. The length of the protrusions 151P protruding in the Z direction, expressed as an example using the length L, is L / 200 or more and L / 2 or less. The length of the protrusions 151P protruding in the X direction and the length of the protrusions 151P protruding in the Z direction may be equal to or different from each other.

[0038] <Characteristics Evaluation> Figure 6 shows a model of a conductive pattern used to evaluate reflection characteristics. The model in Figure 6 has eight rows of unit cells 20 in the X direction and six rows in the Y direction, as shown in Figure 5B. The analysis space 101 in which this model is placed is surrounded by an electromagnetic wave absorber 102. A plane wave of 28.0 GHz is incident at an incident angle of 0° using general-purpose three-dimensional electromagnetic field simulation software, and the scattering cross section of the reflected wave is analyzed. The scattering cross section, i.e., the radar cross section (RCS), is used as an index of the ability to reflect incident electromagnetic waves.

[0039] For metasurfaces that reflect at a reflection angle different from the incident angle, the calculated power reflection efficiency must be corrected. An ideal conductive plate is a perfect specular reflector, reflecting electromagnetic waves in the same direction for normal incidence, whereas a metasurface reflects electromagnetic waves in a direction different from the incident angle. The power reflection efficiency of a metasurface is calculated by dividing the power reflection efficiency calculated from the gain value (dB) by the correction value.

[0040] The reflected electric field at the lossless metasurface determined by the model pattern in Figure 6 is E ＭＲ , the reflected electric field at an ideal conducting plate is E ＰＥＣ Then, the correction value ε ｐ W | E ＭＲ / E ＰＥＣ | ２ |E ＭＲ / E ＰＥＣ |is,

[0041] or,

[0042] Here, θ is the incident angle to the metasurface, and φ is the reflection angle in the case of the corresponding regular reflection. If the reflection angle of the metasurface is θ = 50° or θr = 50°, the incident angle is θi = 0°, and the reflection angle of regular reflection is φ = 25°, the correction value ε ｐ is 0.7826.

[0043] Figure 7 shows the analysis space 101 for the electromagnetic wave simulation. The thickness direction of the layer structure of the electromagnetic wave reflecting panel 10 is the Z direction, the width direction of the hollow pattern 151 (see Figure 5B) of the model in Figure 6 is the X direction, and the length direction is the Y direction, and the analysis space is expressed as (size in the X direction) x (size in the Y direction) x (size in the Z direction). When the frequency of the incident electromagnetic wave is 28.0 GHz, the size of the analysis space 101 is set to 111.8 mm x 32.1 mm x 3.7 mm. The boundary condition is a design in which electromagnetic wave absorbers 102 are arranged around the periphery of the analysis space 101.

[0044] FIG. 8 is a schematic diagram of the XZ plane of the analysis space 101 surrounded by the electromagnetic wave absorber 102. The power reflection efficiency is calculated by changing the radius of curvature of the corners of the hollow patterns 151 constituting the conductive pattern 15 within this analysis space 101. All of the conductive patterns 15 used in the simulation are the same. The six hollow patterns 151 constituting the unit cell 20 are hollow rectangles with a uniform outer periphery width W1 of 1.5 mm and a uniform inner periphery width W2 of 1.0 mm, and their lengths L are 2.5349 mm, 2.7342 mm, 3.2636 mm, 1.4708 mm, 1.9762 mm, and 2.2889 mm, respectively. The lengths of the hollow portions in the Y direction are 2.3349 mm, 2.5342 mm, 3.0636 mm, 1.2708 mm, 1.9762 mm, and 2.0889 mm, respectively. In this design, the width of each hollow pattern 151 in the vertical (Y) direction is 0.25 mm, and the width of each hollow pattern 151 in the horizontal (X) direction is 0.1 mm. The spacing G between adjacent hollow patterns 151 in the X direction is uniformly 0.829 mm. The area occupancy rate of the conductive pattern 15 relative to the dielectric layer 11 is 11.0%, and the transmittance is 63.1%.

[0045] Example 1 Example 1 corresponds to Example 1. A 0.7 mm thick polycarbonate film was used as the dielectric layer 11. A 0.36 mm thick Ag-based multilayer ground layer 12 was provided on one side of the polycarbonate film, and a 0.03 mm thick conductive pattern 15 formed of copper foil was bonded to the other side with a 0.01 mm thick adhesive layer 13 to produce a reflective film. The conductive pattern 15 of the reflective film includes six hollow patterns 151 as unit cells 20, each having a width W1 of 1.5 mm, four rounded points on the inner periphery (inner edge) with a curvature radius R of 0.5 mm, and a hollow portion with a width W2 of 1.0 mm. The line width of the hollow patterns 151 is 0.25 mm.

[0046] 5A , each of the protrusions 151P extends outward in the X direction from one of the four corners of the hollow pattern 151. The protrusions 151P have a width of 0.2 mm in the Z direction and a length of 0.2 mm in the X direction.

[0047] At this time, the lengths (long side lengths) of the six hollow patterns 151 in the Z direction within the unit cell 20 were multiple combinations ranging from 1.5 mm to 5.0 mm. Therefore, when the length L of the long side of the hollow pattern 151 is used, the length of the protrusion 151P of the six hollow patterns 151 is L [mm] × 4 / 100 to L [mm] × 13 / 100.

[0048] This reflective film was sandwiched between two 2.0 mm thick polycarbonate substrates. An electromagnetic wave reflective panel with the laminated structure shown in Figure 4 was fabricated using 400 μm thick ethylene acetate glycol as adhesive layers 23 and 24. A 30.0 GHz electromagnetic wave was incident on this electromagnetic wave reflective panel from the conductive pattern 15 side at an incident angle of 0° and reflected at an angle of 50°. The RCS was analyzed to calculate the power reflection efficiency for horizontally polarized and vertically polarized waves. The horizontally polarized wave is a polarized wave that oscillates in a direction parallel to the horizontal line segment (short side) of the hollow pattern 151. The vertically polarized wave is a polarized wave that oscillates in a direction parallel to the vertical line segment (long side) of the hollow pattern 151.

[0049] When an incident 30.0 GHz electromagnetic wave is reflected at a reflection angle of 50°, the gain value (peak value of the reflected waveform) at 50° in the RCS plot is −1.8560 dB for vertical polarization and −3.579 dB for horizontal polarization. ｐ After correction with ρ = 0.7826, the power reflection efficiency was 71.6% for vertical polarization and 49.3% for horizontal polarization. A power reflection efficiency of over 70% was obtained for one polarization and over 40% for the other polarization.

[0050] Furthermore, in the configuration of Example 1, when the length L of the hollow pattern 151 in the long side direction (Z direction) was changed in 0.1 mm increments from 0.1 mm to 6.0 mm, which is the vertical length of the unit cell 20, the length L at which the reflection phase was 0° was 2.15 mm.

[0051] Example 2 Example 1 is Example 2. A 0.7 mm thick polycarbonate film was used as the dielectric layer 11. A 0.36 mm thick Ag-based multilayer ground layer 12 was provided on one side of the polycarbonate film, and a 0.03 mm thick conductive pattern 15 formed of copper foil was bonded to the other side with a 0.01 mm thick adhesive layer 13 to produce a reflective film. The conductive pattern 15 of the reflective film includes six hollow patterns 151 as unit cells 20, each having a width W1 of 1.5 mm, four rounded points on the inner periphery (inner edge) with a curvature radius R of 0.5 mm, and a hollow portion with a width W2 of 1.0 mm. The line width of the hollow patterns 151 is 0.25 mm.

[0052] Furthermore, the hollow pattern 151 has four protrusions 151P arranged at the four corners, and each protrusion 151P extends outward in the Z direction from one of the four corners of the hollow pattern 151 as shown in Fig. 5B. The size of each protrusion 151P is 0.2 mm in width in the X direction and 0.2 mm in length in the Z direction.

[0053] At this time, the lengths (long side lengths) of the six hollow patterns 151 in the Z direction within the unit cell 20 were multiple combinations ranging from 1.5 mm to 5.0 mm. Therefore, when the length L of the long side of the hollow pattern 151 is used, the length of the protrusions 151P of the six hollow patterns 151 is L [mm] × 4 / 100 to L [mm] 13 / 100.

[0054] This reflective film was sandwiched between two 2.0 mm thick polycarbonate substrates. An electromagnetic wave reflective panel with the laminated structure shown in Figure 4 was fabricated using 400 μm thick ethylene acetate glycol as adhesive layers 23 and 24. A 30.0 GHz electromagnetic wave was incident on this electromagnetic wave reflective panel from the conductive pattern 15 side at an incident angle of 0° and reflected at an angle of 50°. The RCS was analyzed to calculate the power reflection efficiency for horizontally polarized and vertically polarized waves. The horizontally polarized wave is a polarized wave that oscillates in a direction parallel to the horizontal line segment (short side) of the hollow pattern 151. The vertically polarized wave is a polarized wave that oscillates in a direction parallel to the vertical line segment (long side) of the hollow pattern 151.

[0055] When an incident 30.0 GHz electromagnetic wave is reflected at a reflection angle of 50°, the gain value (peak value of the reflected waveform) at 50° in the RCS plot is −1.8150 dB for vertical polarization and −2.500 dB for horizontal polarization. ｐ After correction with ρ = 0.7826, the power reflection efficiency was 72.3% for vertical polarization and 63.2% for horizontal polarization. A power reflection efficiency of over 70% was obtained for one polarization and over 40% for the other polarization.

[0056] Furthermore, in the configuration of Example 2, when the length L of the hollow pattern 151 in the long side direction (Z direction) was changed in 0.1 mm increments from 0.1 mm to 6.0 mm, which is the vertical length of the unit cell 20, the length L at which the reflection phase was 0° was 2.05 mm.

[0057] Example 3 Example 3 is Example 3. A 0.7 mm thick polycarbonate film was used as the dielectric layer 11. A 0.36 mm thick Ag-based multilayer ground layer 12 was provided on one side of the polycarbonate film, and a 0.03 mm thick conductive pattern 15 formed of copper foil was bonded to the other side with a 0.01 mm thick adhesive layer 13 to produce a reflective film. The conductive pattern 15 of the reflective film includes six hollow patterns 151 as unit cells 20, each having a width W1 of 1.5 mm, four rounded points on the inner periphery (inner edge) with a curvature radius R of 0.5 mm, and a hollow portion with a width W2 of 1.0 mm. The line width of the hollow patterns 151 is 0.25 mm.

[0058] The hollow pattern 151 also has four protrusions 151P arranged at the four corners, and each protrusion 151P extends outward in the X and Z directions from the four corners of the hollow pattern 151 as shown in FIG. 5D . The protrusions 151P protruding in the X direction have a width in the Z direction of 0.2 mm and a length in the X direction of 0.2 mm. The protrusions 151P protruding in the Z direction have a width in the X direction of 0.2 mm and a length in the Z direction of 0.2 mm.

[0059] At this time, the lengths (long side lengths) of the six hollow patterns 151 in the Z direction within the unit cell 20 were multiple combinations ranging from 0.5 mm to 4.0 mm. Therefore, when the length L of the long side of the hollow pattern 151 is used, the length of the protrusion 151P of the six hollow patterns 151 is L [mm] × 4 / 10 to L [mm] × 5 / 100.

[0060] This reflective film was sandwiched between two 2.0 mm thick polycarbonate substrates. An electromagnetic wave reflective panel with the laminated structure shown in Figure 4 was fabricated using 400 μm thick ethylene acetate glycol as adhesive layers 23 and 24. A 30.0 GHz electromagnetic wave was incident on this electromagnetic wave reflective panel from the conductive pattern 15 side at an incident angle of 0° and reflected at an angle of 50°. The RCS was analyzed to calculate the power reflection efficiency for horizontally polarized and vertically polarized waves. The horizontally polarized wave is a polarized wave that oscillates in a direction parallel to the horizontal line segment (short side) of the hollow pattern 151. The vertically polarized wave is a polarized wave that oscillates in a direction parallel to the vertical line segment (long side) of the hollow pattern 151.

[0061] When an incident 30.0 GHz electromagnetic wave is reflected at a reflection angle of 50°, the gain value (peak value of the reflected waveform) at 50° in the RCS plot is −1.9450 dB for vertical polarization and −3.750 dB for horizontal polarization. ｐ After correction with ρ = 0.7826, the power reflection efficiency was 70.2% for vertical polarization and 47.4% for horizontal polarization. A power reflection efficiency of over 70% was obtained for one polarization and over 40% for the other polarization.

[0062] Furthermore, in the configuration of Example 3, when the length L of the hollow pattern 151 in the long side direction (Z direction) was changed in 0.1 mm increments from 0.1 mm to 6.0 mm, which is the vertical length of the unit cell 20, the length L at which the reflection phase was 0° was 2.05 mm.

[0063] Example 4 Example 4 is Example 4. A 0.7 mm thick polycarbonate film was used as the dielectric layer 11. A 0.36 mm thick Ag-based multilayer ground layer 12 was provided on one side of the polycarbonate film, and a 0.03 mm thick conductive pattern 15 formed of copper foil was bonded to the other side with a 0.01 mm thick adhesive layer 13 to produce a reflective film. The conductive pattern 15 of the reflective film includes six hollow patterns 151 as unit cells 20, each having a width W1 of 1.5 mm, four rounded points on the inner periphery (inner edge) with a curvature radius R of 0.5 mm, and a hollow portion with a width W2 of 1.0 mm. The line width of the hollow patterns 151 is 0.25 mm.

[0064] 5A, each of the protrusions 151P extends outward in the X direction from one of the four corners of the hollow pattern 151. The protrusions 151P have a width of 0.25 mm in the Z direction and a length of 0.25 mm in the X direction.

[0065] At this time, the lengths (long side lengths) of the six hollow patterns 151 in the Z direction within the unit cell 20 were a plurality of combinations ranging from 1.5 mm to 5.0 mm. Therefore, when the length L of the long side of the hollow pattern 151 is used, the length of the protrusion 151P of the six hollow patterns 151 is L [mm] × 5 / 100 to L [mm] × 17 / 100.

[0066] This reflective film was sandwiched between two 2.0 mm thick polycarbonate substrates. An electromagnetic wave reflective panel with the laminated structure shown in Figure 4 was fabricated using 400 μm thick ethylene acetate glycol as adhesive layers 23 and 24. A 30.0 GHz electromagnetic wave was incident on this electromagnetic wave reflective panel from the conductive pattern 15 side at an incident angle of 0° and reflected at an angle of 50°. The RCS was analyzed to calculate the power reflection efficiency for horizontally polarized and vertically polarized waves. The horizontally polarized wave is a polarized wave that oscillates in a direction parallel to the horizontal line segment (short side) of the hollow pattern 151. The vertically polarized wave is a polarized wave that oscillates in a direction parallel to the vertical line segment (long side) of the hollow pattern 151.

[0067] When an incident 30.0 GHz electromagnetic wave is reflected at a reflection angle of 50°, the gain value (peak value of the reflected waveform) at 50° in the RCS plot is −1.8250 dB for vertical polarization and −2.250 dB for horizontal polarization. ｐ After correction with ρ = 0.7826, the power reflection efficiency was 72.1% for vertical polarization and 67.0% for horizontal polarization. A power reflection efficiency of 70% or more was obtained for one polarization and 40% or more for the other polarization.

[0068] Furthermore, in the configuration of Example 4, when the length L of the hollow pattern 151 in the long side direction (Z direction) was changed in 0.1 mm increments from 0.1 mm to 6.0 mm, which is the vertical length of the unit cell 20, the length L at which the reflection phase was 0° was 2.15 mm.

[0069] Example 5 Example 5 is Example 5. A 0.7 mm thick polycarbonate film was used as the dielectric layer 11. A 0.36 mm thick Ag-based multilayer ground layer 12 was provided on one side of the polycarbonate film, and a 0.03 mm thick conductive pattern 15 formed of copper foil was bonded to the other side with a 0.01 mm thick adhesive layer 13 to produce a reflective film. The conductive pattern 15 of the reflective film includes six hollow patterns 151 as unit cells 20, each having a width W1 of 1.5 mm, four rounded points on the inner periphery (inner edge) with a curvature radius R of 0.5 mm, and a hollow portion with a width W2 of 1.0 mm. The line width of the hollow patterns 151 is 0.25 mm.

[0070] 5A, each of the protrusions 151P extends outward in the X direction from one of the four corners of the hollow pattern 151. The protrusions 151P have a width of 0.05 mm in the Z direction and a length of 0.05 mm in the X direction.

[0071] At this time, the lengths (long side lengths) of the six hollow patterns 151 in the Z direction within the unit cell 20 were a plurality of combinations ranging from 0.5 mm to 5.3 mm. Therefore, when the length L of the long side of the hollow pattern 151 is used, the length of the protrusion 151P of the six hollow patterns 151 is L [mm] × 1 / 10 to L [mm] × 9 / 1000.

[0072] This reflective film was sandwiched between two 2.0 mm thick polycarbonate substrates. An electromagnetic wave reflective panel with the laminated structure shown in Figure 4 was fabricated using 400 μm thick ethylene acetate glycol as adhesive layers 23 and 24. A 30.0 GHz electromagnetic wave was incident on this electromagnetic wave reflective panel from the conductive pattern 15 side at an incident angle of 0° and reflected at an angle of 50°. The RCS was analyzed to calculate the power reflection efficiency for horizontally polarized and vertically polarized waves. The horizontally polarized wave is a polarized wave that oscillates in a direction parallel to the horizontal line segment (short side) of the hollow pattern 151. The vertically polarized wave is a polarized wave that oscillates in a direction parallel to the vertical line segment (long side) of the hollow pattern 151.

[0073] When an incident 30.0 GHz electromagnetic wave is reflected at a reflection angle of 50°, the gain value (peak value of the reflected waveform) at 50° in the RCS plot is −1.8250 dB for vertical polarization and −2.250 dB for horizontal polarization. ｐ After correction with ρ = 0.7826, the power reflection efficiency was 72.1% for vertical polarization and 67.0% for horizontal polarization. A power reflection efficiency of 70% or more was obtained for one polarization and 40% or more for the other polarization.

[0074] Furthermore, in the configuration of Example 5, when the length L of the hollow pattern 151 in the long side direction (Z direction) was changed in 0.1 mm increments from 0.1 mm to 6.0 mm, which is the vertical length of the unit cell 20, the length L at which the reflection phase was 0° was 2.15 mm.

[0075] Example 6 Example 6 is Example 6. A 0.7 mm thick polycarbonate film was used as the dielectric layer 11. A 0.36 mm thick Ag-based multilayer ground layer 12 was provided on one side of the polycarbonate film, and a 0.03 mm thick conductive pattern 15 formed of copper foil was bonded to the other side with a 0.01 mm thick adhesive layer 13 to produce a reflective film. The conductive pattern 15 of the reflective film included six hollow patterns 151 as unit cells 20, each with a width W1 of 1.5 mm, no rounding at the four points on the inner periphery (inner edge) (see FIG. 5C ), and a hollow portion with a width W2 of 1.0 mm. The line width of the hollow patterns 151 was 0.25 mm.

[0076] The hollow pattern 151 also has four protrusions 151P arranged at the four corners, and each protrusion 151P extends outward in the X direction from one of the four corners of the hollow pattern 151 as shown in Fig. 5C. The size of the protrusions 151P is 0.25 mm in width in the Z direction and 0.25 mm in length in the X direction.

[0077] At this time, the lengths (long side lengths) of the six hollow patterns 151 in the Z direction within the unit cell 20 were a plurality of combinations ranging from 0.5 mm to 5.0 mm. Therefore, when the length L of the long side of the hollow pattern 151 is used, the length of the protrusion 151P of the six hollow patterns 151 is L [mm] × 1 / 2 to L [mm] × 5 / 100.

[0078] This reflective film was sandwiched between two 2.0 mm thick polycarbonate substrates. An electromagnetic wave reflective panel with the laminated structure shown in Figure 4 was fabricated using 400 μm thick ethylene acetate glycol as adhesive layers 23 and 24. A 30.0 GHz electromagnetic wave was incident on this electromagnetic wave reflective panel from the conductive pattern 15 side at an incident angle of 0° and reflected at an angle of 50°. The RCS was analyzed to calculate the power reflection efficiency for horizontally polarized and vertically polarized waves. The horizontally polarized wave is a polarized wave that oscillates in a direction parallel to the horizontal line segment (short side) of the hollow pattern 151. The vertically polarized wave is a polarized wave that oscillates in a direction parallel to the vertical line segment (long side) of the hollow pattern 151.

[0079] When an incident 30.0 GHz electromagnetic wave is reflected at a reflection angle of 50°, the gain value (peak value of the reflected waveform) at 50° on the RCS plot is −1.8250 dB for vertical polarization and −4.200 dB for horizontal polarization. ｐ After correction with ρ = 0.7826, the power reflection efficiency was 72.1% for vertical polarization and 41.7% for horizontal polarization. A power reflection efficiency of over 70% was obtained for one polarization and over 40% for the other polarization.

[0080] Furthermore, in the configuration of Example 6, when the length L of the hollow pattern 151 in the long side direction (Z direction) was changed in 0.1 mm increments from 0.1 mm to 6.0 mm, which is the vertical length of the unit cell 20, the length L at which the reflection phase was 0° was 2.15 mm.

[0081] Example 7 Example 7 corresponds to Comparative Example 1. A 0.7 mm thick polycarbonate film was used as the dielectric layer 11. A 0.36 mm thick Ag-based multilayer ground layer 12 was provided on one side of the polycarbonate film, and a 0.03 mm thick conductive pattern 15 formed of copper foil was bonded to the other side with a 0.01 mm thick adhesive layer 13 to produce a reflective film. The conductive pattern 15 of the reflective film includes six hollow patterns 151 as unit cells 20, each with a width W1 of 1.5 mm, no rounding at the four inner periphery (inner edge), and a hollow portion with a width W2 of 1.0 mm. The line width of the hollow patterns 151 is 0.25 mm. In Example 7, the hollow patterns 151 do not have protrusions 151P.

[0082] This reflective film was sandwiched between two 2.0 mm thick polycarbonate substrates. An electromagnetic wave reflective panel with the laminated structure shown in Figure 4 was fabricated using 400 μm thick ethylene acetate glycol as adhesive layers 23 and 24. A 30.0 GHz electromagnetic wave was incident on this electromagnetic wave reflective panel from the conductive pattern 15 side at an incident angle of 0° and reflected at an angle of 50°. The RCS was analyzed to calculate the power reflection efficiency for horizontally polarized and vertically polarized waves. The horizontally polarized wave is a polarized wave that oscillates in a direction parallel to the horizontal line segment (short side) of the hollow pattern 151. The vertically polarized wave is a polarized wave that oscillates in a direction parallel to the vertical line segment (long side) of the hollow pattern 151.

[0083] When an incident 30.0 GHz electromagnetic wave is reflected at a reflection angle of 50°, the gain value (peak value of the reflected waveform) at 50° in the RCS plot is −1.9200 dB for vertical polarization and −10.500 dB for horizontal polarization. ｐ After correction with ρ = 0.7826, the power reflection efficiency was 70.6% for vertical polarization and 10.0% for horizontal polarization. A power reflection efficiency of 70% or more was achieved for one polarization, but a power reflection efficiency of 40% or more was not achieved for the other polarization.

[0084] Furthermore, in the configuration of Example 7, when the length L of the hollow pattern 151 in the long side direction (Z direction) was changed in 0.1 mm increments from 0.1 mm to 6.0 mm, which is the vertical length of the unit cell 20, the length L at which the reflection phase was 0° was 2.35 mm.

[0085] Example 8 Example 8 is Comparative Example 2. A 0.7 mm thick polycarbonate film was used as the dielectric layer 11. A ground layer 12 made of a 0.36 mm thick Ag-based multilayer film was provided on one side of the polycarbonate film, and a conductive pattern 15 made of 0.03 mm thick copper foil was bonded to the other side with a 0.01 mm thick adhesive layer 13 to produce a reflective film. The conductive pattern 15 of the reflective film had a shape that included a pattern with a width W1 of 1.5 mm as a unit cell 20. The pattern with a width W1 of 1.5 mm was not a hollow pattern and did not have a hollow portion.

[0086] This reflective film was sandwiched between two 2.0 mm thick polycarbonate substrates. An electromagnetic wave reflective panel with the laminated structure shown in Figure 4 was fabricated using 400 μm thick ethylene acetate glycol as adhesive layers 23 and 24. A 30.0 GHz electromagnetic wave was incident on this electromagnetic wave reflective panel from the conductive pattern 15 side at an incident angle of 0° and reflected at an angle of 50°. The RCS was analyzed to calculate the power reflection efficiency for horizontally polarized and vertically polarized waves. The horizontally polarized wave is a polarized wave that oscillates in a direction parallel to the horizontal line segments (short sides) of the six conductive patterns 15. The vertically polarized wave is a polarized wave that oscillates in a direction parallel to the vertical line segments (long sides) of the six conductive patterns 15.

[0087] When an incident 30.0 GHz electromagnetic wave is reflected at a reflection angle of 50°, the gain value (peak value of the reflected waveform) at 50° in the RCS plot is −1.9200 dB for vertical polarization and −10.500 dB for horizontal polarization. ｐ After correction with ρ = 0.7826, the power reflection efficiency was 70.6% for vertical polarization and 10.0% for horizontal polarization. A power reflection efficiency of 70% or more was achieved for one polarization, but a power reflection efficiency of 40% or more was not achieved for the other polarization.

[0088] In addition, in the configuration of Example 8, when the length L of the pattern in the long side direction (Z direction) was changed in 0.1 mm increments from 0.1 mm to 6.0 mm, which is the vertical length of the unit cell 20, the length L at which the reflection phase was 0° was 2.45 mm.

[0089] The results of Examples 1 to 8 show that by forming a reflecting surface with a periodic arrangement of hollow rectangular conductive patterns and each hollow pattern 151 having protrusions 151P protruding outward from its corners, both horizontally and vertically polarized waves can be reflected in controlled directions. Furthermore, in Examples 1 to 6, the length L at which the reflection phase is 0° can be shortened compared to Examples 7 and 8. This increases the variation in the reflection phase (pattern dimensions) within a unit cell in which multiple patterns are arranged, thereby broadening the design options for the angle of incidence, the angle of reflection, the beam width, and other parameters. Furthermore, by providing a curvature R at least in part of the inner corners of the hollow pattern 151 with a radius of curvature R of 1 / 10 to 1 / 2 of the width of the hollow, i.e., the width w1 of the inner periphery, current concentration can be suppressed, electrode reflection efficiency can be maintained, and both polarized waves can be effectively reflected in controlled directions.

[0090] The above configuration is not limited to reflecting vertically incident 30.0 GHz electromagnetic waves in a direction 50° from the normal. By appropriately designing the length L, widths W1 and W2, spacing G, and size (length and width) of the individual hollow patterns 151 constituting the unit cells 20, horizontally and vertically polarized electromagnetic waves of a selected frequency band can be reflected in the desired direction. The in-plane size of the electromagnetic wave reflecting panel 10 can be appropriately selected from a range of 30 cm x 30 cm to 3 m x 3 m. The entire surface of the electromagnetic wave reflecting panel 10 may be a metasurface formed with a repeating period of the unit cells 20, or a portion may be a metasurface and the remainder may be a specular reflective surface. The outermost surface of the electromagnetic wave reflecting panel 10 may be covered with a weather-resistant protective layer. The electromagnetic wave reflecting device 60 and electromagnetic wave reflecting fence 100 of the embodiment can be installed indoors or outdoors and are compatible with both polarized waves.

[0091] <Effects> The electromagnetic wave reflecting panel 10A includes a dielectric layer 11, a conductive pattern 15 provided on one surface of the dielectric layer 11, and a ground layer 12 provided on the other surface of the dielectric layer 11. The conductive pattern 15 is formed of a periodic arrangement of rectangular hollow patterns 151, reflects electromagnetic waves in a predetermined band selected from 1 MHz or more and 300 GHz or less, and has protrusions 151P that protrude outward from at least some of the corners of the hollow patterns 151. The presence of the protrusions 151P makes it possible to increase the amount of phase change in the reflected waves.

[0092] Therefore, it is possible to realize an electromagnetic wave reflecting panel 10A that reflects both horizontally polarized waves and vertically polarized waves in controlled directions.

[0093] Furthermore, the quadrangular hollow pattern 151 is a rectangular ring having two first extending portions extending in a first direction (X direction) in a plan view and two second extending portions extending in a second direction (Z direction) in a plan view, and the protruding portion 151P may protrude in the extending direction of the first extending portion or the second extending portion. By having the protruding portion 151P protruding in the extending direction of the first extending portion or the second extending portion, it is possible to increase the amount of change in the phase of the reflected wave, and a structure is obtained that makes it easy to control the phase of the reflected wave.

[0094] Furthermore, the length of the protrusion 151P may be equal to or greater than L / 200 and equal to or less than L / 2, where L is the length of the long side of the rectangular hollow pattern 151. By setting the length of the protrusion 151P to be equal to or greater than L / 200 and equal to or less than L / 2, it is possible to increase the amount of change in the phase of the reflected wave, thereby obtaining a structure that makes it easy to control the phase of the reflected wave.

[0095] The corners at the tips of the protrusions 151P may be rounded, which makes it easier to control the phase of the reflected wave.

[0096] The following supplementary notes are further disclosed with respect to the above embodiments. (Supplementary Note 1) An electromagnetic wave reflecting panel including: a dielectric layer; a conductive pattern provided on one surface of the dielectric layer; and a ground layer provided on the other surface of the dielectric layer, wherein the conductive pattern is formed of a periodic arrangement of rectangular hollow patterns and reflects electromagnetic waves in a predetermined band selected from 1 MHz or more and 300 GHz or less, and has protrusions protruding outward from at least some of the corners of the hollow patterns. (Supplementary Note 2) The electromagnetic wave reflecting panel according to Supplementary Note 1, wherein the hollow patterns are rectangular annular having two first extending portions extending in a first direction in a plan view and two second extending portions extending in a second direction in a plan view, and the protrusions protrude in the extension direction of the first extending portions or the second extending portions. (Supplementary Note 3) The electromagnetic wave reflecting panel according to Supplementary Note 1 or 2, wherein the length of the protrusion is not less than L / 200 and not more than L / 2, where L is the length of the long side of the hollow pattern. (Supplementary Note 4) The electromagnetic wave reflecting panel according to any one of Supplementary Notes 1 to 3, wherein at least some of the corners of the inner periphery of the hollow pattern are rounded with the predetermined radius of curvature. (Supplementary Note 5) The electromagnetic wave reflecting panel according to Supplementary Note 4, wherein the predetermined radius of curvature is not less than 1 / 10 and not more than 1 / 2 of the width of the hollow. (Supplementary Note 6) The electromagnetic wave reflecting panel according to any one of Supplementary Notes 1 to 5, wherein the conductive pattern includes a periodic repetition of unit cells formed of a plurality of the hollow patterns, and the unit cell is formed by a plurality of the hollow patterns having the same width but different lengths, which are arranged in a first direction along the same central axis, and the first direction is a direction parallel to the short side of the hollow pattern. (Supplementary Note 7) The electromagnetic wave reflecting panel according to any one of Supplementary Notes 1 to 6, wherein the area occupancy rate of the conductive pattern with respect to the dielectric layer is 10.0% or more and 45% or less. (Supplementary Note 8) The electromagnetic wave reflecting panel according to any one of Supplementary Notes 1 to 7, wherein the conductive pattern is joined to the dielectric layer by an adhesive layer, and the area occupancy rate of the adhesive layer with respect to the dielectric layer is 9.0% or more and 50.0% or less. (Supplementary Note 9) An electromagnetic wave reflecting device comprising: the electromagnetic wave reflecting panel according to any one of Supplementary Notes 1 to 8; and a frame that holds the electromagnetic wave reflecting panel.(Supplementary Note 10) An electromagnetic wave reflecting fence in which a plurality of electromagnetic wave reflecting devices according to Supplementary Note 9 are connected by the frame.

[0097] This international application claims priority based on Japanese Patent Application No. 2024-010140, filed on January 26, 2024, the entire contents of which are incorporated herein by reference.

[0098] 10, 10A, 10B, 10-1, 10-2, 10-3 Electromagnetic wave reflecting panel 11 Dielectric layer 12 Ground layer 13, 23, 24 Adhesive layer 15 Conductive pattern 20 Unit cell 21, 22 Dielectric substrate 50 Frame (side frame) 57 Top frame 58 Bottom frame 60, 60-1, 60-2, 60-3 Electromagnetic wave reflecting device 100 Electromagnetic wave reflecting fence 151, 151a to 151f Hollow pattern 151P Protrusion

Claims

1. A dielectric layer, a conductive pattern provided on one surface of the dielectric layer, and a ground layer provided on the other surface of the dielectric layer, wherein the conductive pattern is formed by a periodic arrangement of square hollow patterns, reflects electromagnetic waves in a predetermined band selected from 1 MHz or more and 300 GHz or less, and has a protruding portion protruding outward from at least a part of a corner of the hollow pattern, the electromagnetic wave reflection panel.

2. The hollow pattern is in a rectangular ring shape having two first extending portions extending in a first direction in a plan view and two second extending portions extending in a second direction in a plan view, and the protruding portion protrudes in the extending direction of the first extending portion or the second extending portion. The electromagnetic wave reflection panel according to claim 1.

3. When the length of the long side of the hollow pattern is L, the length of the protruding portion is L / 200 or more and L / 2 or less. The electromagnetic wave reflection panel according to claim 1.

4. At least a part of a corner of the inner periphery of the hollow pattern is rounded with the predetermined radius of curvature. The electromagnetic wave reflection panel according to claim 1.

5. The predetermined radius of curvature is 1 / 10 or more and 1 / 2 or less of the width of the hollow. The electromagnetic wave reflection panel according to claim 4.

6. The conductive pattern includes a periodic repetition of unit cells formed by a plurality of the hollow patterns. In the unit cell, a plurality of the hollow patterns having the same width and different lengths are arranged in a first direction along the same central axis, and the first direction is a direction parallel to the short side of the hollow pattern. The electromagnetic wave reflection panel according to claim 1.

7. The area occupancy rate of the conductive pattern with respect to the dielectric layer is 10.0% or more and 45% or less. The electromagnetic wave reflection panel according to claim 1.

8. The conductive pattern is joined to the dielectric layer by an adhesive layer, and the area occupancy rate of the adhesive layer with respect to the dielectric layer is 9.0% or more and 50.0% or less. The electromagnetic wave reflection panel according to claim 1.

9. An electromagnetic wave reflection device including the electromagnetic wave reflection panel according to any one of claims 1 to 8 and a frame for holding the electromagnetic wave reflection panel.

10. An electromagnetic wave reflection fence in which a plurality of the electromagnetic wave reflection devices according to claim 9 are connected by the frame.

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