Radio wave transmitting body and window material

Abstract

The present invention increases radio wave transmittance of a window material. A radio wave transmitting body 4 is translucent and is disposed on a surface of a window material 1 including a transparent plate 2 and a metal layer 3 laminated on the transparent plate, the radio wave transmitting body 4 including a conductive layer 41 and a base layer 43 supporting the conductive layer. A plurality of conductive layers 41 is disposed periodically in the vertical and horizontal directions in a pattern having non-conductive regions 42C, conductive regions 41 surrounding the regions 42C, and non-conductive regions 42A, 42B surrounding the regions 41. A width W of the region 41 is half the difference between a line segment PB connecting two opposing sides of region 42C and a line segment PA connecting two opposing sides of region 42A, and a combination of width W and GAP / 2, which is half the spacing between regions 41, is a combination of W being 1.2-7.4 mm and GAP / 2 being 1.2-2.9 mm, or a combination of W being 11.9-21.0 mm and GAP / 2 being 0.5-5.5 mm, and the radio wave intensity after transmission for incident radio waves with a frequency of 1 GHz is greater than 0 dB.

Description

Radio wave transmitting body and window material

[0001] The present invention relates to a radio wave transmitting body that is placed on the surface of a window material, and to a window material that includes a radio wave transmitting body.

[0002] In recent years, window glass (hereinafter referred to as window material) with excellent heat blocking properties in summer and heat insulating properties in winter has become increasingly popular as an energy-saving measure for buildings. In such window materials, a Low-E film is formed on the entire surface of one of the surfaces that constitutes the window material.

[0003] On the other hand, it is known that when a Low-E film is formed on a window material, the transmittance of radio waves decreases over a wide frequency band. The creation of radio wave blind zones inside a building is problematic. Therefore, in conventional window materials, as in Patent Document 1, for example, a portion of the Low-E film is removed by laser processing to form a radio wave transmittance area, thereby improving the indoor radio wave communication environment.

[0004] Japanese Patent Application Laid-Open No. 2023-113772

[0005] However, when manufacturing a window material, removing a portion of the Low-E film as in Patent Document 1 cannot be said to be efficient for production. Moreover, it is not realistic to perform such a Low-E film removal process on window materials that have already been installed in buildings. There is a need for a technology that can easily increase the radio wave transmittance of window materials.

[0006] An object of the present invention is to provide a technique for easily increasing the radio wave transmittance of a window material.

[0007] In order to achieve the above object, the present invention encompasses the following subjects: (Item 1) A light-transmitting radio wave transmitting body disposed on the surface of a window material comprising at least one transparent plate and a metal layer laminated on the at least one transparent plate, comprising: a conductive layer; and a base layer supporting the conductive layer, wherein the conductive layer is periodically arranged vertically and horizontally in a pattern having a first non-conductive region, a conductive region surrounding the first non-conductive region, and a second non-conductive region surrounding the conductive region, wherein the width W of the conductive region is half the difference between the length of a first line segment PB connecting two opposing sides of the first non-conductive region and the length of a second line segment PA connecting two opposing sides of the second non-conductive region, and wherein a combination of the width W of the conductive region and GAP / 2, which is half the gap GAP between the conductive regions in adjacent patterns, is such that the width W is 1.2 mm or more and 7.4 mm or less, and half the gap GAP / 2 is 1.2 mm or more and 2.9 mm or less, or Item 2. The radio wave transparent body according to Item 1, wherein the width W is 11.9 mm or more and 21.0 mm or less, and half the gap GAP / 2 is 0.5 mm or more and 5.5 mm or less, and the radio wave intensity after transmission for an incident radio wave with a frequency of 1 GHz is greater than 0 dB. (Item 3) The radio wave transparent body according to Item 2, wherein the first non-conductive region is rectangular, and the second non-conductive region is rectangular. (Item 4) The radio wave transparent body according to Item 2, wherein the combination of the width W and half the gap GAP / 2 is: the width W is 2.0 mm or more and 6.0 mm or less, and half the gap GAP / 2 is 0.5 mm or more and 1.5 mm or less, or the width W is 13.7 mm or more and 21.0 mm or less, and half the gap GAP / 2 is 0.5 mm or more and 5.5 mm or less, and the radio wave intensity after transmission is 4 dB or more. (Item 4) A window material comprising: at least one transparent plate; a metal layer laminated on the at least one transparent plate; and the radio wave transmitting body according to any one of Items 1 to 3 attached to the transparent plate or the metal layer.

[0008] According to the present invention, a technique for easily increasing the radio wave transmittance of a window material can be provided.

[0009] FIG. 1 is a cross-sectional view of a window material according to an embodiment. FIG. 2 is a diagram showing a schematic configuration of the entire radio wave transmitting body according to an embodiment. (A) is a plan view, and (B) is an enlarged view of part A in (A). FIG. 1 is a cross-sectional view of a radio wave transmitting body according to an embodiment. FIG. 2 is a cross-sectional view of a window material according to modified example 1. FIG. 3 is a cross-sectional view of a window material according to modified example 2. FIG. 4 is a waveguide model used in a numerical simulation according to an example. FIG. 5 is a pattern of a conductive layer used in a numerical simulation according to an example. FIG. 6 is a scatter diagram for explaining the results of a numerical simulation according to an example.

[0010] Embodiments of the present invention will now be described with reference to the drawings. A window material 1 according to this embodiment has a light-transmitting radio wave transmitting body 4 disposed on its surface. Although the window material 1 according to this embodiment has reduced radio wave transmittance over a wide frequency band due to the inclusion of the metal layer 3, the radio wave transmittance body 4, which is a metasurface film, disposed on the surface improves radio wave transmittance.

[0011] First, the window material 1 on which the radio wave transmitting body 4 is disposed will be described below. Next, each component of the window material 1, including the radio wave transmitting body 4, will be described.

[0012] (Window Material) As shown in Fig. 1 , the window material 1 is a double glazing having a plurality of transparent plates 2. The window material 1 includes the plurality of transparent plates 2, a metal layer 3, and a radio wave transmitting body 4. The window material 1 also includes a spacer 5 that maintains a distance between the plurality of transparent plates 2.

[0013] As shown in FIGS. 2 and 3, the radio wave transmitting body 4 includes a base layer 43 attached to the transparent plate 2 or the metal layer 3, and a conductive layer 41 formed on the base layer 43.

[0014] Because the window material 1 according to this embodiment is configured in this manner, it is possible to increase the radio wave transmittance only for radio waves in a specific frequency band, even if the metal layer 3 reflects or blocks radio waves. Moreover, because it is only necessary to attach the radio wave transmitting body 4 to the window material 1 on which the existing metal layer 3 is laminated, the window material 1 can be made highly manufacturable.

[0015] The window material 1 according to this embodiment is used, for example, as window glass in buildings, as well as light-receiving windows in doors, fixed windows in ceilings, floors, etc. Furthermore, the window material 1 according to this embodiment can also be used for windows in automobiles, aircraft, ships, trains, ropeways, etc. in addition to buildings.

[0016] In the window material 1, the specific frequency band of radio waves that can enhance the radio wave transmittance is preferably any radio wave in the range of 0.5 GHz to 60 GHz. In this embodiment, the transparent plate 2 is configured to enhance the radio wave transmittance in the 5 GHz frequency band (3 GHz to 5 GHz, 25 GHz to 30 GHz). However, there are no particular restrictions on the frequency band in which the radio wave transmittance of the window material 1 is to be enhanced. The specific frequency band in which the radio wave transmittance is to be enhanced can be set to a desired frequency band by changing the shape of the conductive layer 41 in the radio wave transmitting body 4.

[0017] (Transparent Plate 2) The transparent plate 2 is a transparent plate material. In this specification, "transparent" means that the light transmittance is 10% or more with respect to the peak wavelength of the light before incidence, preferably 50% or more, and more preferably 80% or more. In other words, "transparent" in this specification also includes "semi-transparent" in which the light transmittance is, for example, about 30% with respect to the peak wavelength of the light before incidence. Furthermore, the transparent plate 2 is not limited to being colorless and transparent, and may be colored.

[0018] The transparent plate 2 according to the present embodiment is preferably a glass plate. Examples of the glass plate include float glass, figured glass, frosted glass, wired glass, and tempered glass. However, examples of the transparent plate 2 include an acrylic plate and a polycarbonate plate in addition to a glass plate.

[0019] There are no particular limitations on the shape of the transparent plate 2. The shape of the transparent plate 2 may be, for example, a rectangular shape in a plan view, a circular shape in a plan view, a pentagonal shape in a plan view, a hexagonal shape in a plan view, an elliptical shape in a plan view, etc. Here, "plan view" means that the main surface of the transparent plate 2 is viewed from a direction perpendicular to the main surface.

[0020] 1, the multiple transparent plates 2 are arranged at regular intervals in the thickness direction of the window material 1. Of the adjacent transparent plates 2, one transparent plate 2 may be referred to as the "first transparent plate 21" and the other transparent plate 2 may be referred to as the "second transparent plate 22."

[0021] A spacer 5 is disposed between the first transparent plate 21 and the second transparent plate 22. The spacer 5 maintains the distance between the two adjacent transparent plates 21, 22. The outer peripheries of the transparent plates 2 are surrounded by a sealing material (not shown), and the space (intermediate layer 6) between the two adjacent transparent plates 21, 22 is formed airtight. The intermediate layer 6 is preferably filled with an insulating gas. Examples of the insulating gas include an inert gas such as argon gas. However, the intermediate layer 6 may also be filled with air. Alternatively, the intermediate layer 6 may be a vacuum.

[0022] The first transparent plate 21 has a first surface 211 and a second surface 212. Similarly, the second transparent plate 22 has a first surface 221 and a second surface 222. The first surfaces 211 and 221 are one of the surfaces (main surfaces) in the thickness direction of the transparent plate 2. The second surfaces 212 and 222 are main surfaces opposite the first surfaces 211 and 221. In this embodiment, the first surfaces 211 and 221 refer to surfaces of adjacent transparent plates 2 that face each other (inner surfaces in the thickness direction of the window material 1), and the second surfaces 212 and 222 refer to outer surfaces of the window material 1.

[0023] The window material 1 in this embodiment is a double-pane glass made up of two transparent plates 2, but it may also be a triple-pane glass made up of three transparent plates 2, or it may be made up of four or more transparent plates 2.

[0024] (Metal Layer 3) The metal layer 3 is laminated on the transparent plate 2 to improve the heat insulating properties of the window material 1. The metal layer 3 is preferably a Low-E film. There are no particular limitations on the Low-E film, and examples thereof include a film in which a transparent dielectric layer, an infrared reflective layer, and a transparent dielectric layer are laminated in this order. Examples of the transparent dielectric layer include metal oxides (e.g., zinc oxide, tin oxide) and metal nitrides. Examples of the infrared reflective layer include metal films (e.g., silver), semiconductor films, etc.

[0025] The metal layer 3 may be laminated on any one of the plurality of transparent plates 2. In this embodiment, the metal layer 3 is laminated on the first surface 211 of the first transparent plate 21. The metal layer 3 is laminated over the entire surface of the first surface 211 of the transparent plate 2. The metal layer 3 is laminated on the transparent plate 2 by, for example, coating, vapor deposition, adhesion, welding, or the like.

[0026] (Radio wave transmitting body 4) The radio wave transmitting body 4 is attached to the transparent plate 2 or the metal layer 3. By attaching the radio wave transmitting body 4 to the transparent plate 2 or the metal layer 3, it is possible to increase the radio wave transmittance of the window material 1 in a specific frequency band of radio waves. As shown in Figures 2 and 3, the radio wave transmitting body 4 has a base layer 43, a conductive layer 41, and a protective film 45 laminated in this order. The radio wave transmitting body 4 according to this embodiment is attached to the second surface 212 of the first transparent plate 21. The radio wave transmitting body 4 may cover the entire surface of the transparent plate 2, or may be attached to only a part of the entire surface.

[0027] (Substrate Layer 43) The substrate layer 43 supports the conductive layer 41. In this embodiment, the substrate layer 43 is transparent. The substrate layer 43 is attached to the transparent plate 2 or the metal layer 3. An adhesive layer (hereinafter referred to as the first adhesive layer 46) is provided on the surface of the substrate layer 43 opposite the conductive layer 41. The first adhesive layer 46 preferably has a large number of capsules filled with adhesive before bonding, and is structured so that the adhesive ruptures when pressure is applied from the substrate layer 43 toward the transparent plate 2 or the metal layer 3 during bonding, thereby enabling bonding. However, the first adhesive layer 46 may also be an adhesive applied without being filled into capsules. Examples of adhesives include synthetic resins such as acrylic resin, silicone resin, and polyvinyl alcohol resin.

[0028] In this embodiment, the outer shape of the base material layer 43 is quadrangular (more specifically, square) in plan view, as shown in Fig. 2. However, there are no particular limitations on the shape of the base material layer 43, and examples thereof include a polygon, a circle, an ellipse, a star, a heart, and the like. The thickness of the base material layer 43 is uniform over the entire surface. However, the thickness of the base material layer 43 does not have to be uniform.

[0029] Examples of the substrate layer 43 include synthetic resin, fiber reinforced plastics (FRP), carbon, and glass. Examples of the synthetic resin include one or more selected from the group consisting of PET (polyethylene terephthalate), polyethylene, polypropylene, polyvinyl chloride, polystyrene, polymethyl methacrylate, polyester, polyformaldehyde, polyamide, polyphenylene ether, vinylidene chloride, polyvinyl acetate, polyvinyl acetal, AS resin, ABS resin, acrylic resin, fluororesin, nylon resin, polyacetal resin, polycarbonate resin, polyamide resin, and polyurethane resin. The substrate layer 43 may be a composite material of these synthetic resins. The substrate layer 43 according to this embodiment is made of a PET film.

[0030] The thickness of the base layer 43 is, for example, preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 20 μm or more. On the other hand, the upper limit of the thickness of the base layer 43 is, for example, preferably 500 μm or less, more preferably 130 μm or less, and even more preferably 100 μm or less.

[0031] The base layer 43 preferably has flexibility. The modulus of longitudinal elasticity of the base layer 43 is, for example, preferably 0.01 GPa or more, more preferably 1 GPa or more, and even more preferably 8 GPa or more. On the other hand, the upper limit of the modulus of longitudinal elasticity of the base layer 43 is, for example, preferably 80 GPa or less, more preferably 30 GPa or less, and even more preferably 20 GPa or less.

[0032] (Conductive layer 41) The conductive layer is a metal microstructure having a structure finer than the wavelength of the target radio wave (electromagnetic wave). The conductive layer corresponds to a split ring resonator in a metasurface (metamaterial) and is also called a split ring resonator (SRR). In this specification, the conductive layer may be referred to as a "split ring resonator portion."

[0033] The conductive layer 41 includes a conductor and constitutes a transmission surface. The conductive layer 41 is formed on a base layer 43. Methods for forming the conductive layer 41 on the base layer 43 include, for example, laminating a thin film formed by embedding the conductive layer 41 in a thin-film dielectric on the base layer 43, or forming the conductive layer 41 on the base layer 43 without using a dielectric.

[0034] Examples of the conductor constituting the conductive layer 41 include one or more of silver, gold, copper, platinum, aluminum, titanium, silicone, indium tin oxide, and alloys (e.g., alloys containing nickel, chromium, and molybdenum). Examples of alloys containing nickel, chromium, and molybdenum include various grades of Hastelloy B-2, B-3, C-4, C-2000, C-22, C-276, G-30, N, W, and X.

[0035] The thickness of the conductive layer 41 is preferably 10 nm or more, more preferably 30 nm or more, and even more preferably 100 nm or more. On the other hand, the upper limit of the thickness of the conductive layer 41 is preferably 10 μm or less, more preferably 5 μm or less, and even more preferably 4 μm or less. When the thickness of the conductive layer 41 is 10 nm or more, appropriate radio wave intensity can be ensured.

[0036] The conductive layer 41 preferably has a relative dielectric constant of 7 or more. On the other hand, the upper limit of the relative dielectric constant is preferably 10,000 or less.

[0037] 2B , for example. In this embodiment, the conductive layer 41 has a pattern including a first non-conductive region 42C, a conductive region 41 surrounding the first non-conductive region 42C, and second non-conductive regions 42A and 42B surrounding the conductive region 41, and the plurality of conductive layers 41 are periodically arranged vertically and horizontally.

[0038] The first non-conductive region 42C is surrounded by the conductive region 41. The conductive region 41 is surrounded by one or more linear non-conductive regions 42A and 42B. The conductive region 41 is surrounded by the second non-conductive regions 42A and 42B.

[0039] In this embodiment, the first non-conductive region 42C is rectangular (square). The conductive region 41 surrounds the periphery of the rectangular first non-conductive region 42C in a rectangular shape. The second non-conductive regions 42A, 42B surround the periphery of the conductive region 41 in a rectangular shape. Specifically, the linear non-conductive regions 42A, 42B are arranged at equal intervals along the vertical and horizontal directions, and the non-conductive region 42A along the horizontal direction and the non-conductive region 42B along the vertical direction are connected at their overlapping intersections, and these non-conductive regions 42A, 42B constitute the second non-conductive region.

[0040] The width W of the conductive region 41 is expressed as half the difference between the length of the line segment PB connecting two opposing sides of the first non-conductive region 42C and the length of the line segment PA connecting two opposing sides of the second non-conductive region {(PA-PB) / 2}. Furthermore, using the gap GAP between the conductive regions 41, 41 between adjacent patterns in the vertical or horizontal direction, the width of the second non-conductive regions 42A, 42B is expressed as GAP / 2. The non-conductive regions 42 (42A, 42B, 42C) may be filled with the adhesive of the adhesive layer 44.

[0041] (Protective Film 45) The protective film 45 can protect the conductive layer 41 by covering the conductive layer 41. The protective film 45 has a size corresponding to the base material layer 43 in a plan view. Examples of the protective film 45 include films made of synthetic resins. Examples of synthetic resins include one or more selected from the group consisting of PET (polyethylene terephthalate), COP (cycloolefin polymer), polyethylene, polypropylene, polyvinyl chloride, polystyrene, polymethyl methacrylate, polyester, polyformaldehyde, polyamide, polyphenylene ether, vinylidene chloride, polyvinyl acetate, polyvinyl acetal, AS resin, ABS resin, acrylic resin, fluororesin, nylon resin, polyacetal resin, polycarbonate resin, polyamide resin, and polyurethane resin.

[0042] The protective film 45 preferably contains fluorine. The protective film 45 containing fluorine can prevent transmission of ultraviolet rays, and therefore can protect the conductive layer 41 from ultraviolet rays.

[0043] The thickness of the protective film 45 is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 15 μm or more. On the other hand, the upper limit of the thickness of the protective film 45 is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 25 μm or less.

[0044] The protective film 45 is adhered to the base layer 43 via an adhesive layer (hereinafter referred to as the second adhesive layer 44). Examples of the second adhesive layer 44 include a synthetic resin, a rubber adhesive sheet, etc. Examples of the synthetic resin include an acrylic resin, a silicone resin, and a polyvinyl alcohol resin.

[0045] <Modifications> The above embodiment is merely one of various embodiments of the present invention. The embodiment can be modified in various ways depending on the design, etc., as long as the object of the present invention can be achieved. Modifications of the embodiment are listed below. The modifications described below can be applied in appropriate combinations.

[0046] (Variation 1) In the above embodiment, the window material 1 has multiple transparent plates 2, but as shown in Fig. 4, the window material 1 may have only one transparent plate 2. As shown in Fig. 4, a metal layer 3 is laminated on a first surface 211 of the transparent plate 2. A radio wave transmitting body 4 is attached to the metal layer 3. Note that the radio wave transmitting body 4 may also be attached to a second surface 212 on which no metal layer 3 is provided.

[0047] Furthermore, the metal layer 3 is not limited to a Low-E film and may be a heat-shielding film. When the metal layer 3 is a heat-shielding film, it may be attached to the first surface 211 or the second surface 212 of the transparent plate 2, for example, after the window material 1 is installed in the window frame.

[0048] (Variant 2) In the above embodiment, the radio wave transparent body 4 was attached to a transparent plate 2 (first transparent plate 21) on which the metal layer 3 was laminated, but as shown in Figure 5, the radio wave transparent body 4 may also be attached to a transparent plate 2 (second transparent plate 22) other than the transparent plate 2 on which the metal layer 3 was laminated.

[0049] The distance between the radio wave transmitting body 4 and the metal layer 3 is preferably 110 mm or less, more preferably 30 mm or less, and even more preferably 10 mm or less. On the other hand, the lower limit of the distance between the radio wave transmitting body 4 and the metal layer 3 may be 0 mm. In other words, the radio wave transmitting body 4 may be directly bonded to the metal layer 3 (see FIG. 4).

[0050] Example In this example, the degree to which radio wave transmission is improved by placing a radio wave transmitting body on the surface of a window material was confirmed by numerical simulation. The numerical simulation was performed based on the waveguide model 9 shown in Fig. 6. For the radio wave transmitting body included in the illustrated waveguide model 9, the conductive layer pattern (i.e., the metastructure conditions) shown in Fig. 7 was specified, and the intensity of radio waves transmitted through the window material was calculated for this specified waveguide model 9.

[0051] The line segment PA, line segment PB, and gap GAP shown in Figure 7 were defined as variables defining the pattern of the conductive layer of the radio wave transmitting body. The radio wave intensity transmitted through the window material was calculated by comprehensively combining the multiple conditions (numerical ranges) shown in Table 1 and comprehensively varying the dimensions of these defined variables PA, PB, and GAP within the numerical ranges shown in Table 1. In this example, the radio wave intensity transmitted through the window material was calculated for a total of 16,800 conditions combining the variables PA, PB, and GAP shown in Table 1. In this example, the frequency of the radio wave incident on the window material was 1 GHz. The intensity of the incident radio wave was calculated by multiplying the radio wave intensity transmitted through the window material (Low-E) by -60.9578 dB (minus 60.9578 dB). The results of the numerical simulation are shown in Figure 8. When considering the results, it was determined that radio wave transmittance was improved when the radio wave intensity after transmission of the incident radio wave was greater than 0 dB.

[0052]

[0053] To facilitate understanding of the embodiment, in FIGS. 6 and 7, the same components as those described in the above embodiment are denoted by the same reference numerals.

[0054] The scatter diagram in FIG. 8 plots the combinations of dimensions of the variables PA, PB, and GAP for which the intensity of the radio wave transmitted through the window material was greater than 0 dB in the numerical simulation.

[0055] 8A shows the combinations of dimensions for which the radio wave intensity is greater than 0 dB but less than 4 dB, and the combinations of dimensions for which the radio wave intensity is 4 dB or greater. The vertical axis of the graph represents the width W of the conductive region. The width W of the conductive region corresponds to half the difference between the length of a first line segment PB connecting two opposing sides of the first non-conductive region and the length of a second line segment PA connecting two opposing sides of the second non-conductive region {(PA-PB) / 2}. The horizontal axis of the graph represents half the gap GAP between the conductive regions of adjacent patterns (GAP / 2).

[0056] 8B shows the combinations of dimensions that result in radio wave intensity greater than 0 dB and less than 4 dB. As shown in FIG. 8B, numerical simulations have shown that when the combination of the width W of the non-conductive region and the gap GAP / 2 is either the first or second combination shown below, radio waves are transmitted with an intensity greater than 0 dB and less than 4 dB. The first combination is a width W of 1.2 mm or more and 7.4 mm or less, and a gap GAP / 2 of 1.2 mm or more and 2.9 mm or less. The second combination is a width W of 11.9 mm or more and 21.0 mm or less, and a gap GAP / 2 of 0.5 mm or more and 5.5 mm or less.

[0057] Figure 8(C) shows the combinations of dimensions that result in radio wave intensity of 4 dB or more. As shown in Figure 8(C), numerical simulations have shown that when the combination of the width W of the non-conductive region and the gap GAP / 2 is either the third or fourth combination shown below, radio waves are transmitted with an intensity of 4 dB or more. The third combination is a width W of 2.0 mm or more and 6.0 mm or less, and a gap GAP / 2 of 0.5 mm or more and 1.5 mm or less. The fourth combination is a width W of 13.7 mm or more and 21.0 mm or less, and a gap GAP / 2 of 0.5 mm or more and 5.5 mm or less.

[0058] REFERENCE SIGNS LIST 1 window material 2 transparent plate 21 first transparent plate 211 first surface 212 second surface 22 second transparent plate 221 first surface 222 second surface 3 metal layer 4 radio wave transparent body (metasurface film) 41 conductive layer 42 non-conductive region 44 adhesive layer 43 substrate layer 45 protective film

Claims

1. A light-transmitting radio wave transmitting body disposed on the surface of a window material comprising at least one transparent plate and a metal layer laminated on the at least one transparent plate, comprising: a conductive layer; and a base layer supporting the conductive layer, wherein the conductive layer is periodically arranged vertically and horizontally in a pattern having a first non-conductive region, a conductive region surrounding the first non-conductive region, and a second non-conductive region surrounding the conductive region, wherein the width W of the conductive region is half the difference between the length of a first line segment PB connecting two opposing sides of the first non-conductive region and the length of a second line segment PA connecting two opposing sides of the second non-conductive region, and wherein the combination of the width W of the conductive region and GAP / 2, which is half the gap GAP between the conductive regions in adjacent patterns, is such that the width W is 1.2 mm or more and 7.4 mm or less, and half the gap GAP / 2 is 1.2 mm or more and 2.9 mm or less, or A radio wave transmitting body having a combination of the width W of 11.9 mm or more and 21.0 mm or less and half the gap GAP / 2 of 0.5 mm or more and 5.5 mm or less, wherein the radio wave intensity after transmission of an incident radio wave having a frequency of 1 GHz is greater than 0 dB.

2. The radio wave transparent body according to claim 1, wherein the first non-conductive area is rectangular, and the second non-conductive area is rectangular.

3. The radio wave transmitting body according to claim 2, wherein the combination of the width W and half the gap GAP / 2 is: the width W is 2.0 mm or more and 6.0 mm or less, and half the gap GAP / 2 is 0.5 mm or more and 1.5 mm or less, or the width W is 13.7 mm or more and 21.0 mm or less, and half the gap GAP / 2 is 0.5 mm or more and 5.5 mm or less, and the radio wave intensity after transmission is 4 dB or more.

4. A window material comprising: at least one transparent plate; a metal layer laminated on said at least one transparent plate; and a radio wave transparent body according to any one of claims 1 to 3 attached to said transparent plate or said metal layer.

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