Radio wave transmissive body and surface material

Abstract

The present invention improves radio wave transmissivity.　This radio wave transmissive body comprises a glass sheet having a first surface, and a surface material having arranged therein a plurality of conductors or slots facing the first surface. When λ represents the wavelength [m] of a radio wave, d represents the distance [m] between the first surface and the surface material, X represents the reactance [Ω] of the surface material, θ represents the phase [rad] of a reflection coefficient of the first surface, and Φ=θ-(4×π×d) / λ is defined, ln|X| is not less than (0.5308×Φ4+3.3993×Φ3+7.5554×Φ2+7.8195×Φ+8.9954) in a range of -π<Φ<0, and is not more than (-0.5321×Φ4+3.4069×Φ3-7.5685×Φ2+7.8267×Φ-8.9960) in a range of 0<Φ<π.

Description

Radio wave transparent body and surface material

[0001] The present disclosure relates to radio wave transparent bodies and surface materials.

[0002] Conventionally, a technique for increasing the transmission of radio waves through a substrate by using a slotted conductive structure is known (see, for example, Patent Document 1).

[0003] US Patent Application Publication No. 2021 / 0050881

[0004] Glass sheets used for window glass and the like may have reduced radio wave transmittance depending on the conditions under which radio waves pass through the glass sheet.

[0005] An object of the present disclosure is to improve radio wave transparency.

[0006] A radio wave transmitting body of a first aspect comprises: a glass plate having a first surface; and a surface material facing said first surface and having a plurality of conductors or slots arranged therein; wherein, when λ is the wavelength of the radio wave [m], d is the distance [m] between said first surface and said surface material, X is the reactance [Ω] of said surface material, θ is the phase [rad] of the reflection coefficient of said first surface, and Φ=θ-(4×π×d) / λ, ln|X| is (0.5308×Φ) in the range of -π<Φ<0. ４ +3.3993 x Φ ３ +7.5554×Φ ２ +7.8195×Φ+8.9954) or greater, and in the range of 0<Φ<π, (-0.5321×Φ ４ +3.4069 x Φ ３ -7.5685 x Φ ２ +7.8267×Φ−8.9960).

[0007] A radio wave transmitting body of a second aspect is the radio wave transmitting body of the first aspect, and the surface material may have the plurality of conductors or the slots periodically arranged.

[0008] A radio wave transmitting body of a third aspect is the radio wave transmitting body of the first or second aspect, wherein the glass plate may be single glass, laminated glass, wired glass or figured glass.

[0009] A fourth aspect of the radio wave transmitting body comprises: a double glazing for architecture having a first surface; and a surface material facing the first surface and having a plurality of conductors or slots arranged therein; wherein, when λ is the wavelength of the radio wave [m], d is the distance [m] between the first surface and the surface material, X is the reactance [Ω] of the surface material, θ is the phase [rad] of the reflection coefficient of the first surface, and Φ=θ-(4×π×d) / λ, ln|X| is (0.1943×Φ) in the range of -π<Φ<0. ４ +1.6348 x Φ ３ +4.5737 x Φ ２ +6.0874×Φ+8.7403) or greater, and in the range of 0<Φ<π, (-0.2317×Φ ４ +1.8267 x Φ ３ -4.8632 x Φ ２ +6.2007×Φ−8.7304).

[0010] A radio wave transmitting body of a fifth aspect is the radio wave transmitting body of the fourth aspect, wherein the surface material may have the plurality of conductors or the plurality of slots periodically arranged.

[0011] A radio wave transmitting body of a sixth aspect is the radio wave transmitting body of the fourth or fifth aspect, wherein the double glazing may have a laminated structure including a first glass plate, a second glass plate having the first surface, and an intermediate layer disposed between the first glass plate and the second glass plate, or may have a laminated structure including a first glass plate, a second glass plate, a third glass plate having the first surface, a first intermediate layer disposed between the first glass plate and the second glass plate, and a second intermediate layer disposed between the second glass plate and the third glass plate.

[0012] A seventh aspect of the radio wave transmitting body comprises: a double glazing having a first surface; and a surface material facing the first surface and having an array of conductors or slots; the double glazing includes a conductive layer having a gap formed therein where no conductors are present; and when λ is the wavelength of the radio wave [m], d is the distance [m] between the first surface and the surface material, X is the reactance [Ω] of the surface material, θ is the phase [rad] of the reflection coefficient of the first surface, and Φ = θ - (4 × π × d) / λ, ln|X| is (0.0491 × Φ) in the range of -π < Φ < 0.４ +0.8137 x Φ ３ +3.0701 x Φ ２ +5.1075×Φ+8.5746) or more, and in the range of 0<Φ<π, (-0.0511×Φ ４ +0.8285 x Φ ３ -3.1070 x Φ ２ +5.1438×Φ−8.5850).

[0013] An eighth aspect of the radio wave transmission body is the radio wave transmission body of the seventh aspect, wherein the surface material may have the plurality of conductors or the slots periodically arranged.

[0014] A ninth aspect of the radio wave transparent body is the radio wave transparent body of the seventh or eighth aspect, wherein the double glazing may have a laminated structure including a first glass plate, a second glass plate having the first surface, an intermediate layer disposed between the first glass plate and the second glass plate, and the conductive layer disposed between the first glass plate or the second glass plate and the intermediate layer; or may have a laminated structure including a first glass plate, a second glass plate, a third glass plate having the first surface, a first intermediate layer disposed between the first glass plate and the second glass plate, a second intermediate layer disposed between the second glass plate and the third glass plate, and the conductive layer disposed between the first glass plate and the first intermediate layer or between the second intermediate layer and the third glass plate.

[0015] A radio wave transmission body of a tenth aspect is the radio wave transmission body of any one of the seventh to ninth aspects, wherein the conductive layer may have a capacitance of 0.1 pF or more and 1.0 pF or less.

[0016] The radio wave transmitting body of an eleventh aspect is the radio wave transmitting body of any one of the seventh to tenth aspects, wherein the conductive layer may be a low-emission film.

[0017] A surface material of a twelfth aspect is a surface material that can be installed to face a first surface of a glass plate, the surface material having an array of conductors or slots facing the first surface, and where λ is the wavelength of radio waves [m], d is the distance [m] between the first surface and the surface material, X is the reactance [Ω] of the surface material, θ is the phase [rad] of the reflection coefficient of the first surface, and Φ = θ - (4 × π × d) / λ, ln|X| is (0.5308 × Φ) in the range of -π < Φ < 0. ４ +3.3993 x Φ ３ +7.5554×Φ ２ +7.8195×Φ+8.9954) or greater, and in the range of 0<Φ<π, (-0.5321×Φ ４ +3.4069 x Φ ３ -7.5685 x Φ ２ +7.8267×Φ−8.9960).

[0018] A thirteenth aspect of the surface material is a surface material that can be installed to face a first surface of architectural double glazing, wherein the surface material has an array of conductors or slots that face the first surface, and where λ is the wavelength of radio waves [m], d is the distance [m] between the first surface and the surface material, X is the reactance [Ω] of the surface material, θ is the phase [rad] of the reflection coefficient of the first surface, and Φ = θ - (4 × π × d) / λ, ln |X| is (0.1943 × Φ) in the range of -π < Φ < 0. ４ +1.6348 x Φ ３ +4.5737 x Φ ２ +6.0874×Φ+8.7403) or greater, and in the range of 0<Φ<π, (-0.2317×Φ ４ +1.8267 x Φ ３ -4.8632 x Φ ２ +6.2007×Φ−8.7304).

[0019] A surface material of a fourteenth aspect is a surface material that can be installed to face a first surface of double glazing, wherein the surface material has an array of conductors or slots that face the first surface, and the double glazing includes a conductive layer in which a gap where no conductors are present is formed, and where λ is the wavelength of radio waves [m], d is the distance [m] between the first surface and the surface material, X is the reactance [Ω] of the surface material, θ is the phase [rad] of the reflection coefficient of the first surface, and Φ = θ - (4 × π × d) / λ, ln|X| is (0.0491 × Φ) in the range of -π < Φ < 0. ４ +0.8137 x Φ ３ +3.0701 x Φ ２ +5.1075×Φ+8.5746) or more, and in the range of 0<Φ<π, (-0.0511×Φ ４ +0.8285 x Φ ３ -3.1070 x Φ ２ +5.1438×Φ−8.5850).

[0020] According to the present disclosure, radio wave transparency can be improved.

[0021] 1 is a diagram illustrating the periodic structure and equivalent circuit of a grid-type FSS. FIG. 1 is a diagram illustrating the periodic structure and equivalent circuit of a patch-type FSS. FIG. 1 is a diagram illustrating the periodic structure and equivalent circuit of a loop-type FSS. FIG. 1 is a diagram illustrating the periodic structure and equivalent circuit of a loop slot-type FSS. FIG. 2 is a cross-sectional view of an example of a radio wave transmitting body according to the first embodiment. FIG. 3 is a cross-sectional view of an example of a radio wave transmitting body according to the second embodiment. FIG. 4 is a cross-sectional view of an example of a radio wave transmitting body according to the third embodiment. FIG. 5 is a cross-sectional view of an example of a radio wave transmitting body according to the fourth embodiment. FIG. 6 is a cross-sectional view of an example of a radio wave transmitting body according to the fifth embodiment. FIG. 7 is a cross-sectional view of an example of a radio wave transmitting body according to the sixth embodiment. FIG. 8 is a cross-sectional view of an example of a radio wave transmitting body according to the seventh embodiment. FIG. 9 is a table showing thicknesses of glass plates used in the calculation conditions. FIG. 10 is a table showing thicknesses of double glazing used in the calculation conditions. FIG. 11 is a cross-sectional view of a main substrate alone (glass plate alone). FIG. 12 is an equivalent circuit diagram of a main substrate alone (glass plate alone). FIG. 13 is a cross-sectional view of an example of a glass plate used in the second embodiment. FIG. 14 is an equivalent circuit diagram of an example of a glass plate used in the second embodiment. FIG. 15 is a cross-sectional view of an example of double glazing used in the third embodiment. FIG. 16 is an equivalent circuit diagram of an example of double glazing used in the third embodiment. FIG. 1 is an equivalent circuit diagram of an example of double glazing used in a fourth embodiment. FIG. 2 is a cross-sectional view of an example of a radio wave transmission body according to the first embodiment without a space. FIG. 3 is an equivalent circuit diagram of an example of a radio wave transmission body according to the first embodiment without a space. FIG. 4 is a cross-sectional view of an example of a radio wave transmission body according to the first embodiment with a space. FIG. 5 is an equivalent circuit diagram of an example of a radio wave transmission body according to the first embodiment with a space. FIG. 6 is a cross-sectional view of an example of a radio wave transmission body according to the second embodiment without a space. FIG. 7 is an equivalent circuit diagram of an example of a radio wave transmission body according to the second embodiment without a space. FIG. 8 is a cross-sectional view of an example of a radio wave transmission body according to the second embodiment with a space. FIG. 9 is an equivalent circuit diagram of an example of a radio wave transmission body according to the second embodiment with a space. FIG. 10 is a cross-sectional view of an example of a radio wave transmission body according to the third embodiment without a space. FIG. 11 is an equivalent circuit diagram of an example of a radio wave transmission body according to the third embodiment without a space. FIG. 12 is a cross-sectional view of an example of a radio wave transmission body according to the third embodiment with a space. FIG. 13 is an equivalent circuit diagram of an example of a radio wave transmission body according to the third embodiment with a space. FIG. 14 is a cross-sectional view of an example of a radio wave transmission body according to the fourth embodiment without a space. FIG. 15 is an equivalent circuit diagram of an example of a radio wave transmission body according to the fourth embodiment without a space.1 is a cross-sectional view of an example of a radio wave transmission body according to a fourth embodiment with a space; FIG. 2 is an equivalent circuit diagram of an example of a radio wave transmission body according to a fourth embodiment with a space; FIG. 3 is a plan view for explaining an equivalent circuit of an example of a conductive layer in which a space where no conductor is present is formed; FIG. 4 is a plan view for explaining an example of a method for calculating the capacitance of a conductive layer in which a space where no conductor is present is formed; FIG. 5 is a cross-sectional view for explaining an example of a method for calculating the capacitance of a conductive layer in which a space where no conductor is present is formed; FIG. 6 is a diagram for explaining an example of an equivalent circuit used for calculating the capacitance of a conductive layer in which a space where no conductor is present is formed; FIG. 7 is a diagram for explaining the positional relationship in a plan view between a conductive layer in which a space where no conductor is present and an FSS; FIG. 8 is a diagram showing conditions under which radio wave transmission is improved in the case of a single glass plate; FIG. 9 is a diagram showing conditions under which radio wave transmission is improved in the case of double glazing without a conductive layer; FIG. 10 is a diagram showing conditions under which radio wave transmission is improved in the case of double glazing with a conductive layer in which a space where no conductor is present is formed; FIG. 11 is a diagram showing an example of a theoretical calculation result of radio wave transmission of the radio wave transmission body according to the first embodiment; FIG. 12 is a diagram showing an example of a simulation result of radio wave transmission of the radio wave transmission body according to the first embodiment; FIG. 13 is a diagram showing an example of a theoretical calculation result of radio wave transmission of the radio wave transmission body according to the second embodiment; FIG. 14 is a diagram showing an example of a simulation result of radio wave transmission of the radio wave transmission body according to the second embodiment. Fig. 10 is a diagram showing an example of a theoretical calculation result of the radio wave transmittance of the radio wave transmitting body according to the third embodiment. Fig. 11 is a diagram showing an example of a simulation result of the radio wave transmittance of the radio wave transmitting body according to the third embodiment. Fig. 12 is a diagram showing an example of a theoretical calculation result of the radio wave transmittance of the radio wave transmitting body according to the fourth embodiment. Fig. 13 is a diagram showing an example of a simulation result of the radio wave transmittance of the radio wave transmitting body according to the fourth embodiment.

[0022] Hereinafter, the present embodiment will be described with reference to the drawings. Note that for ease of understanding, the scale of each part in the drawings may differ from the actual scale. Directions such as parallel, right angle, orthogonal, horizontal, vertical, up, down, left, and right, as well as terms such as identical and equal, are permitted to be deviated to the extent that they do not impair the functions and effects of the embodiment. The shape of the corners is not limited to right angles and may be rounded in an arched shape. Overlapping may include the meaning of partial overlap. Parallel, right angle, orthogonal, horizontal, and vertical may include approximately parallel, approximately right angle, approximately orthogonal, approximately horizontal, and approximately vertical.

[0023] In this specification, a three-dimensional Cartesian coordinate system with three axial directions (X-axis, Y-axis, and Z-axis) is used. The X-axis, Y-axis, and Z-axis directions represent directions parallel to the X-axis, Y-axis, and Z-axis, respectively. The X-axis, Y-axis, and Z-axis directions are mutually orthogonal. The XY plane, YZ plane, and ZX plane represent imaginary planes parallel to the X-axis and Y-axis directions, imaginary planes parallel to the Y-axis and Z-axis directions, and imaginary planes parallel to the Z-axis and X-axis directions, respectively.

[0024] The radio wave transmitting body according to this embodiment is used to transmit radio waves in a high frequency band (e.g., 0.3 GHz to 300 GHz) such as microwaves and millimeter waves. Such high frequency bands include the UHF band of 0.3 to 3 GHz, the SHF band of 3 to 30 GHz, the Sub6 bands of 0.6 to 4.6 GHz and 3.6 to 4.6 GHz, and the EHF band of 30 to 300 GHz.

[0025] The radio wave transparent body according to the present embodiment may be used in, for example, a fifth generation mobile communication system (so-called 5G), a wireless communication standard such as Bluetooth (registered trademark), or a wireless LAN (Local Area Network) standard such as IEEE 802.11ac. When used in a vehicle, the radio wave transparent body according to the present embodiment may be used in an in-vehicle radar system that emits radar, or a V2X communication system such as vehicle-to-vehicle communication or road-to-vehicle communication.

[0026] The radio wave transmitting body according to this embodiment improves the transmittance of radio waves passing through a substrate (for example, a glass plate, double glazing, etc.) by combining an FSS (Frequency Selective Surface) with the substrate.

[0027] An FSS is a spatial filter with a frequency-selective function that allows only specific frequencies of electromagnetic waves to pass through or be blocked. The FSS is preferably a surface material with a structure in which multiple conductive elements are periodically arranged in an array on a dielectric substrate, or a structure in which slots are periodically arranged in an array on a conductive surface. Periodicity can also be referred to as regularity or repetition.

[0028] An FSS functions as a spatial filter with frequency-selective capability by periodically arranging shapes such as those shown in FIGS. 1A-1D as unit cells. The FSS can be expressed as a reactance using an equivalent circuit such as those shown in FIGS. 1A-1D. If the FSS has conductor loss, a real part is added to the complex impedance of the FSS. The shape of the unit cell that enables the FSS to exhibit frequency-selective capability is not limited to the shapes shown in FIGS. 1A-1D, and other shapes may also be used.

[0029] 1A is a diagram illustrating the periodic structure and equivalent circuit of a grid-type FSS. This FSS has a periodic structure in which cross-shaped conductors 21 are periodically arranged in a plan view. Since this FSS has an inductance component, it functions as, for example, a high-pass filter.

[0030] 1B is a diagram illustrating the periodic structure and equivalent circuit of a patch-type FSS. This FSS has a periodic structure in which rectangular conductors 21 are periodically arranged in a plan view. Since this FSS has a capacitance component, it functions as, for example, a low-pass filter.

[0031] 1C is a diagram illustrating the periodic structure and equivalent circuit of a loop-type FSS. This FSS has a periodic structure in which loop-shaped conductors 21 are periodically arranged in a plan view. This FSS has a series LC component of inductance L and capacitance C, and therefore functions as, for example, a band-stop filter.

[0032] 1D is a diagram illustrating the periodic structure and equivalent circuit of a loop-slot type FSS. This FSS has a periodic structure in which loop-shaped slots 22 are periodically arranged in a plan view. This FSS has a parallel LC component of inductance L and capacitance C, and therefore functions as, for example, a band-pass filter.

[0033] 2A is a cross-sectional view of an example of a radio wave transmitting body according to the first embodiment. The radio wave transmitting body 101 shown in FIG. 2A transmits radio waves in the Z-axis direction. For example, the positive Z-axis direction represents the direction toward the outdoors with respect to the radio wave transmitting body 101, and the negative Z-axis direction represents the direction toward the indoors with respect to the radio wave transmitting body 101.

[0034] The radio wave transmitting body 101 has a layered structure including the main substrate 10 and the FSS 20. The radio wave transmitting body 101 transmits radio waves in the Z-axis direction (the direction from the main substrate 10 to the FSS 20, or the direction from the FSS 20 to the main substrate 10) in which the main substrate 10 and the FSS 20 face each other.

[0035] The main substrate 10 is a dielectric plate having a first surface 10a facing the FSS 20 and a second surface 10b facing in the opposite direction from the first surface 10a. The main substrate 10 is, for example, a glass plate. Specific examples of glass plates include single-plate glass, laminated glass, wire-reinforced glass, and patterned glass. The main substrate 10 may also be a resin plate.

[0036] When a glass plate is used for the main substrate 10, examples of the material of the glass plate include soda lime glass, borosilicate glass, aluminosilicate glass, and alkali-free glass.

[0037] When a resin plate is used for the main substrate 10, the material of the resin plate may be, for example, acrylic, polycarbonate, PVB (polyvinyl butyral), COP (cycloolefin polymer), PET (polyethylene terephthalate), or polyimide.

[0038] The main substrate 10 has a relative dielectric constant ε of 3 or more and 11 or less at a frequency f [GHz] of radio waves incident on the radio wave transmitting body 101. ｒThe dielectric loss tangent (tan δ) of the main substrate 10 is, for example, 1.4 / f or less. For example, at a frequency f of 28 GHz, the dielectric loss tangent of the main substrate 10 is 0.05 or less. The lower limit of the dielectric loss tangent of the main substrate 10 is not particularly limited, but may be any value greater than 0.

[0039] The main substrate 10 is, for example, a glass plate for construction or a vehicle. Architectural glass plates include window glass, glass facades, etc. The main substrate 10 may be a substrate other than a glass plate for construction. The main substrate 10 may include concrete, mortar, cement paste, glass, crystallized glass, ceramic tile, alumina, stone, etc.

[0040] The FSS 20 is, for example, a surface material in which a plurality of conductors or slots facing the first surface 10a are periodically arranged in a plan view. The FSS 20 is a spatial filter having a frequency selection function that transmits or blocks only radio waves of a specific frequency. Specific examples of the FSS 20 are as described above. The FSS 20 is fixed in place while the distance d between the first surface 10a and the FSS 20 is maintained at a predetermined value.

[0041] The FSS 20 may be fixed by a spacer that ensures a distance d between the first surface 10a and the FSS 20. The spacer may be made of a known resin such as a silicone resin, a polysulfide resin, or an acrylic resin. Alternatively, a metal such as aluminum may be used.

[0042] The FSS 20 can be made of conductive materials such as Au (gold), Ag (silver), Cu (copper), Al (aluminum), Cr (chromium), Pd (lead), Zn (zinc), Ni (nickel), and Pt (platinum). The conductive material may be a thin film or an alloy. The conductive material is formed on a substrate such as glass, acrylic, polycarbonate, PVB (polyvinyl butyral), COP (cycloolefin polymer), PET (polyethylene terephthalate), polyimide, ceramics, or sapphire. Examples of glass materials include alkali-free glass, quartz glass, soda-lime glass, borosilicate glass, alkali borosilicate glass, and aluminosilicate glass. The conductive material may be formed in a mesh pattern to provide optical transparency. When the conductor is formed in a mesh shape, the mesh openings may be square, rhombic, or hexagonal. The mesh openings may be randomly shaped by a self-assembly method. The line width of the mesh is preferably 5 to 30 μm, more preferably 6 to 15 μm. The line spacing of the mesh is preferably 50 to 500 μm, more preferably 100 to 300 μm. Furthermore, when the wavelength of the radio wave is λ, the line spacing of the mesh is preferably 0.5 λ or less, more preferably 0.1 λ or less, and even more preferably 0.01 λ or less. When the wavelength of the radio wave is λ, the area of ​​the FSS20 is ２ / 4 or more is preferable, and λ ２ More preferably, the area of ​​the FSS 20 is 6 m ２ Preferably less than 4m ２ The following is more preferable: Here, the area of ​​the FSS 20 means the area of ​​a region where a plurality of conductors or slots are arranged, and for example, when the conductive material is formed in a mesh pattern, the area of ​​the FSS 20 means the sum of the area of ​​the conductive material and the area of ​​the mesh holes.

[0043] The radio waves that have passed through the FSS 20 are incident on the first surface 10a of the main board 10, and the radio waves that have passed through the main board 10 after being incident on the first surface 10a are emitted from the second surface 10b. Alternatively, the radio waves that have passed through the main board 10 are emitted from the first surface 10a to the FSS 20 after being incident on the second surface 10b of the main board 10 after being transmitted through the main board 10, and the radio waves that have passed through the first surface 10a to the FSS 20 are emitted after being transmitted through the FSS 20.

[0044] The wavelength of the radio wave incident on the radio wave transmitting body 101 is assumed to be λ. In order to make the radio wave transmitting body 101 thinner in the Z-axis direction and smaller, the FSS 20 is disposed at a distance d of 0 or more and λ / 2 or less from the first surface 10a. However, the distance d may be λ / 2 or more. For example, when the distance d is 3×λ / 4, the appropriate reactance X of the FSS 20 is the same as when the distance d is λ / 4. The distance d may be 10λ or less. The appropriate reactance X of the FSS 20 is the same value for every difference in the distance d of λ / 2. The appropriate reactance X is an X that satisfies condition A, B, or C described below. A distance d of 0 indicates that the FSS 20 is in contact with the first surface 10a. By setting the distance d between the first surface 10a and the FSS 20 and the reactance X of the FSS 20 to appropriate values, the transmission loss of radio waves through the radio wave transmitting body 101 is reduced compared to the transmission loss of radio waves through the main board 10 alone when the FSS 20 is not present. The reflection of radio waves at the radio wave transmitting body 101 is suppressed by the reduction in transmission loss. Therefore, the reflection at the first surface 10a of radio waves that have passed through the FSS 20 is suppressed, and the radio wave transparency of the radio wave transmitting body 101 is improved compared to the radio wave transparency of the main board 10 alone.

[0045] In the radio wave transmitting body 101, λ is the wavelength of the radio wave [m], d is the distance [m] between the first surface 10a and the FSS 20, X is the reactance [Ω] of the FSS 20, θ is the phase [rad] of the reflection coefficient Γ of the first surface 10a, and Φ = θ - (4 × π × d) / λ. In this case, the radio wave transmitting body 101 has a function "ln|X| is in the range of -π < Φ < 0 and is (0.5308 × Φ ４ +3.3993 x Φ ３ +7.5554×Φ ２ +7.8195×Φ+8.9954) or greater, and in the range of 0<Φ<π, (-0.5321×Φ ４+3.4069 x Φ ３ -7.5685 x Φ ２ +7.8267×Φ−8.9960) or less satisfies condition A. ln|X| represents the natural logarithm of the absolute value of reactance X. rad represents radians.

[0046] When the radio wave transmitting body 101 satisfies condition A, as shown in simulations and examples described later, the transmission loss of radio waves through the radio wave transmitting body 101 is reduced compared to the transmission loss of radio waves through the main board 10 alone when the FSS 20 is not present. The reflection of radio waves at the radio wave transmitting body 101 is suppressed by the reduction in transmission loss. Therefore, the reflection at the first surface 10a of radio waves that have passed through the FSS 20 and arrived is suppressed, and the radio wave transparency of the radio wave transmitting body 101 is improved compared to the radio wave transparency of the main board 10 alone.

[0047] The reflection coefficient Γ is the ratio of the reflected wave that is reflected by the first surface 10a and returns to the incident wave that propagates from the FSS 20 toward the first surface 10a. Ｆ , the voltage amplitude of the reflected wave is V Ｒ Then, "Γ = V Ｒ / V Ｆ When the reflection coefficient Γ is expressed as a complex number (a + jb), the phase θ of the reflection coefficient Γ is defined as tan -1 It is expressed as (b / a).

[0048] By disposing the FSS 20 at a position at a distance d from the first surface 10a of the main board 10, the input impedance Z ｉｎ This is equivalent to changing the reactance Γ of the FSS 20 to match the reactance X so that reflection at the first surface 10a is reduced. However, even if the distance d is the same, the radio wave transmittance of the radio wave transmitting body 101 changes depending on the transmission conditions, such as the configuration of the substrate that transmits the radio waves. Therefore, in the present disclosure, the change in the distance d is expressed as a change in the amount of phase rotation Φ [rad] of the reflection coefficient Γ at the first surface 10a.

[0049] When d = λ / 4, the reflection coefficient Γ rotates by π [rad] on the complex plane, and when d = λ / 2, the reflection coefficient Γ rotates by 2π [rad] on the complex plane. In other words, the amount of phase rotation Φ on the complex plane due to the distance d is 4πd [rad].

[0050] Input impedance Z to the first surface 10a ｉｎ When converting to a reflection coefficient Γ, the phase rotation amount Φ that changes depending on the distance d [m] is expressed as "Φ = θ - (4 × π × d) / λ". However, when the absolute value of Φ (|Φ|) is 0 and π, the input impedance Z ｉｎ Since the imaginary part of is 0, there is no reactance X that improves the radio wave transparency of the radio wave transmitting body 101.

[0051] When the radio wave transmitting body 101 satisfies condition A, the main substrate 10 is not limited to single-plate glass, but may also be laminated glass, wired glass, or patterned glass. The thickness of the interlayer film of the laminated glass, the diameter and pitch of the wires of the wired glass, and the irregularity dimensions of the patterned pattern on the patterned glass are sufficiently short compared to the wavelengths of frequency bands above the UHF band (e.g., the Sub6 band), and therefore have little effect on the reflection coefficient and transmission coefficient. Therefore, when condition A is satisfied, the characteristics of laminated glass, wired glass, or patterned glass can be considered to be equivalent to those of single-plate glass such as float glass.

[0052] Figure 2B is a cross-sectional view of an example of a radio wave transmitting body according to the second embodiment. In the second embodiment, the description of the same configuration, action, and effect as those of the above-mentioned embodiments will be omitted by citing the above description. The radio wave transmitting body 102 shown in Figure 2B has a layered structure including a double-glazing unit 30 and an FSS 20. The radio wave transmitting body 102 transmits radio waves in the Z-axis direction (the direction from the double-glazing unit 30 to the FSS 20, or the direction from the FSS 20 to the double-glazing unit 30) in which the double-glazing unit 30 and the FSS 20 face each other.

[0053] The double glazing 30 is a dielectric plate having a first surface 10a facing the FSS 20 and a second surface 10b facing in the opposite direction to the first surface 10a. The double glazing 30 has a laminated structure including a first glass plate 1 having the second surface 10b, a second glass plate 2 having the first surface 10a, and an interlayer 40 disposed between the first glass plate 1 and the second glass plate 2.

[0054] The properties of the first glass plate 1 and the second glass plate 2 are the same as those of the main substrate 10 described above, but may be different.

[0055] The interlayer 40 is located between the first glass plate 1 and the second glass plate 2. The interlayer 40 is, for example, a hollow layer sealed between the first glass plate 1 and the second glass plate 2. The interlayer 40 may include a gas layer or a solid layer, and in this case, may include both a gas layer and a solid layer. The interlayer 40 may also include a vacuum layer, which is a space filled with gas at a pressure lower than normal atmospheric pressure. A fluid present in the interlayer 40 may be able to flow between the interlayer 40 and the outside of the interlayer 40.

[0056] Specific examples of the gas in the gas layer contained in the intermediate layer 40 include air, oxygen, and inert gases. Examples of inert gases include helium, neon, argon, krypton, xenon, radon, nitrogen, and carbon dioxide.

[0057] Specific examples of solids in the solid layer included in the intermediate layer 40 include foams. Examples of foams include resin foam and aerogel, and examples of resin foam include polystyrene foam and polyethylene foam.

[0058] The double-glazing glass 30 is, for example, double-glazing glass for architectural use. Examples of double-glazing glass for architectural use include window glass and glass facades. The double-glazing glass 30 may also be used for purposes other than architectural use. The same applies to other double-glazing glass described below.

[0059] The radio waves that have passed through the FSS 20 are incident on the first surface 10a of the double-glazing glass 30, and the radio waves that have passed through the first surface 10a and the double-glazing glass 30 are emitted from the second surface 10b. Alternatively, the radio waves that have passed through the double-glazing glass 30 are transmitted from the first surface 10a to the FSS 20, and the radio waves that have passed through the first surface 10a to the FSS 20 are transmitted from the FSS 20 and emitted.

[0060] As in the first embodiment, the FSS 20 is disposed at a distance d from the first surface 10a. By setting the distance d between the first surface 10a and the FSS 20 and the reactance X of the FSS 20 to appropriate values, the radio wave transmittance of the radio wave transmitting body 102 according to the second embodiment is improved compared to the radio wave transmittance of the double glazing 30 alone, as in the first embodiment.

[0061] In the radio wave transmitting body 102, λ is the wavelength of the radio wave [m], d is the distance [m] between the first surface 10a and the FSS 20, X is the reactance [Ω] of the FSS 20, θ is the phase [rad] of the reflection coefficient Γ of the first surface 10a, and Φ = θ - (4 × π × d) / λ. In this case, the radio wave transmitting body 102 has a wavelength of the radio wave [m], and the wavelength of the radio wave is expressed as follows: "ln|X| is (0.1943 × Φ) in the range of -π < Φ < 0. ４ +1.6348 x Φ ３ +4.5737 x Φ ２ +6.0874×Φ+8.7403) or greater, and in the range of 0<Φ<π, (-0.2317×Φ ４ +1.8267 x Φ ３ -4.8632 x Φ ２ +6.2007×Φ−8.7304) or less.

[0062] When the radio wave transmitting body 102 satisfies condition A, and preferably condition B, as shown in the simulations and examples described below, the radio wave transmission loss of the radio wave transmitting body 102 is reduced compared to the radio wave transmission loss of the double-glazing unit 30 alone when the FSS 20 is not present. The reflection of radio waves at the radio wave transmitting body 102 is suppressed by the reduction in transmission loss. Therefore, the reflection at the first surface 10a of the radio waves that have passed through the FSS 20 is suppressed, and the radio wave transmission of the radio wave transmitting body 102 is improved compared to the radio wave transmission of the double-glazing unit 30 alone.

[0063] Figure 2C is a cross-sectional view of an example of a radio wave transmitting body according to a third embodiment. In the third embodiment, the same configurations, functions, and effects as those of the above-described embodiments will not be described further by citing the above descriptions. The radio wave transmitting body 103 shown in Figure 2C has a layered structure including a double-glazing unit 31 and an FSS 20. The double-glazing unit 31 according to the third embodiment differs from the double-glazing unit 30 according to the second embodiment in that a partially decoated conductive layer 50 is disposed between the first glass plate 1 and the interlayer 40.

[0064] The conductive layer 50 is provided on the insulating glass 31. In the illustrated example, the conductive layer 50 is a planar conductor provided on the inner surface of the first glass sheet 1.

[0065] The conductive layer 50 is a conductive layer in which gaps where no conductors are present are formed so that radio waves can pass through the conductive layer 50, and is partially decoated, for example, by partially removing the conductors using a laser or the like. The conductive layer 50 includes a decoated portion 51 formed by partial decoating. The decoated portion 51 is a gap in the conductive layer 50 where no conductors are present. The decoated portion 51 improves the radio wave transmittance of the radio wave transmitting body 103 and the double glazing 31. The number of decoated portions 51 may be one or more. The decoated portion 51 may have a slit-like, rectangular, circular, or other shape.

[0066] The space where no conductor is present is not limited to the decoated portion 51 formed by partial removal of the conductor, but may be formed by other methods. For example, a marginal portion of a conductor formed by patterning or the like may be used as the space where no conductor is present.

[0067] The conductive layer 50 may be transparent or translucent. Specific examples of the conductive layer 50 include a metal film such as an Ag (silver) film, a metal oxide film such as an ITO (indium tin oxide) film, a resin film containing conductive particles, and a laminate of multiple types of films. The conductive layer 50 may be a resin film such as polyethylene terephthalate coated by vapor deposition or the like. The conductive layer 50 may be a film coated with conductive ink or formed into a mesh shape by etching.

[0068] The conductive layer 50 may be a conductive film coated on the inner surface of the first glass plate 1. A specific example of the conductive film is a low-emissivity film such as a Low-E (Low Emissivity) film that exhibits low radiation performance.

[0069] Low emissivity refers to reducing heat transfer due to radiation. Low emissivity films such as Low-E films ensure thermal insulation by suppressing heat transfer due to radiation. The low emissivity film may be a general film, for example, a laminated film including a transparent dielectric film, an infrared reflective film, and a transparent dielectric film in this order. Typical transparent dielectric films are metal oxides and metal nitrides. Typical metal oxides are zinc oxide and tin oxide. Typical infrared reflective films are metal films. Typical metal films are silver (Ag). Here, one or more infrared reflective films may be formed between the transparent dielectric films.

[0070] The conductive layer 50 is not limited to a low-emissivity film such as a Low-E film, and may have other functions as long as it is a conductive layer. For example, the conductive layer 50 may have a function of preventing icing or fogging of the double-glazed glass 31 by generating heat when a voltage is applied.

[0071] The conductive layer 50 may be a conductive film included in a light-control film that can actively change the visible light transmittance of the double-glazed glass 31 by applying an AC voltage. The light-control film has, for example, a molecular layer with optical anisotropy between a pair of opposing resin substrates. A conductive film and an electrode electrically connected to the conductive film are provided on the main surface of each resin substrate. The light-control film can be driven by applying a voltage between the pair of conductive layers via the electrodes.

[0072] The resin substrate is made of, for example, a transparent resin. The resin substrate may have, for example, polyethylene terephthalate (PET), polycarbonate (PC), or cycloolefin polymer (COP). Furthermore, a pair of opposing resin substrates may be made of, for example, a combination of the above-mentioned resins. The thickness of the resin substrate is, for example, in the range of 5 μm to 500 μm, preferably in the range of 10 μm to 200 μm, more preferably in the range of 20 μm to 180 μm, and even more preferably in the range of 50 μm to 150 μm.

[0073] The conductive film may include, for example, a transparent conductive oxide, a transparent conductive polymer, a laminated film of a metal layer and a dielectric layer, silver nanowires, a silver or copper metal mesh, etc. The thickness of the conductive film may be, for example, in the range of 5 nm to 2 μm.

[0074] Examples of molecules having optical anisotropy include liquid crystals. That is, a liquid crystal layer may be used as a molecular layer having optical anisotropy. Examples of the liquid crystal layer include polymer dispersed liquid crystal (PDLC), polymer network liquid crystal (PNLC), and guest-host liquid crystal. Alternatively, iodine or the like may be used as a molecule having optical anisotropy. The light control film may have a suspended particle device (SPD) including such a molecular layer.

[0075] The FSS 20 is disposed at a distance d from the first surface 10a, as in the first embodiment. By setting the distance d between the first surface 10a and the FSS 20 and the reactance X of the FSS 20 to appropriate values, the radio wave transmittance of the radio wave transmitting body 103 according to the third embodiment is improved compared to the radio wave transmittance of the double glazing 31 alone, as in the first embodiment.

[0076] In the radio wave transmitting body 103, λ is the wavelength of the radio wave [m], d is the distance [m] between the first surface 10a and the FSS 20, X is the reactance [Ω] of the FSS 20, θ is the phase [rad] of the reflection coefficient Γ of the first surface 10a, and Φ = θ - (4 × π × d) / λ. In this case, the radio wave transmitting body 103 has a function "ln|X| is in the range of -π < Φ < 0 and is (0.0491 × Φ ４ +0.8137 x Φ ３ +3.0701 x Φ ２ +5.1075×Φ+8.5746) or more, and in the range of 0<Φ<π, (-0.0511×Φ ４ +0.8285 x Φ ３ -3.1070 x Φ ２ +5.1438×Φ−8.5850) or less.

[0077] When the radio wave transmitting body 103 satisfies condition A, and preferably condition C, as shown in the simulations and examples described below, the radio wave transmission loss of the radio wave transmitting body 103 is reduced compared to the radio wave transmission loss of the double-glazing unit 31 alone when the FSS 20 is not present. The reflection of radio waves at the radio wave transmitting body 103 is suppressed by the reduction in transmission loss. Therefore, the reflection at the first surface 10a of the radio waves that have passed through the FSS 20 is suppressed, and the radio wave transmission of the radio wave transmitting body 103 is improved compared to the radio wave transmission of the double-glazing unit 31 alone.

[0078] Figure 2D is a cross-sectional view of an example of a radio wave transmitting body according to a fourth embodiment. In the fourth embodiment, the same configurations, functions, and effects as those of the above-described embodiments will not be described again by citing the above descriptions. The radio wave transmitting body 104 shown in Figure 2D has a layered structure including a double-glazing unit 32 and an FSS 20. The double-glazing unit 32 according to the fourth embodiment differs from the double-glazing unit 31 according to the third embodiment in that a partially decoated conductive layer 50 is disposed between the second glass plate 2 and the interlayer 40.

[0079] The conductive layer 50 is provided on the double-glazing glass 32. In the illustrated example, the conductive layer 50 is a planar conductor provided on the inner surface of the second glass sheet 2. As in the third embodiment, the conductive layer 50 is a conductive layer in which gaps where no conductor is present are formed.

[0080] The FSS 20 is disposed at a distance d from the first surface 10 a, as in the first embodiment. When the radio wave transmitting body 104 according to the fourth embodiment satisfies condition A, and preferably condition C, the radio wave transmittance of the radio wave transmitting body 104 is improved compared to the radio wave transmittance of the double glazing 32 alone, as in the third embodiment.

[0081] Fig. 2E is a cross-sectional view of an example of a radio wave transmitting body according to a fifth embodiment. In the fifth embodiment, the same configurations, actions, and effects as those of the above embodiments will not be described by citing the above descriptions. The radio wave transmitting body 105 shown in Fig. 2E has a layered structure including a double-glazing unit 33 and an FSS 20. The double-glazing unit 33 according to the fifth embodiment differs from the double-glazing unit 30 according to the second embodiment in that it includes two intermediate layers and three glass sheets. The double-glazing unit 33 is also called triple glazing.

[0082] The double glazing 33 is a dielectric plate having a first surface 10a facing the FSS 20 and a second surface 10b facing in the opposite direction to the first surface 10a. The double glazing 33 has a laminated structure including a first glass plate 1 having the second surface 10b, a third glass plate 3 having the first surface 10a, a second glass plate 2 disposed between the first glass plate 1 and the third glass plate 3, a first intermediate layer 41 disposed between the first glass plate 1 and the second glass plate 2, and a second intermediate layer 42 disposed between the second glass plate 2 and the third glass plate 3.

[0083] The characteristics of the first glass plate 1, the second glass plate 2, and the third glass plate 3 are the same as those of the main substrate 10 described above, but may be different.

[0084] The properties of the first intermediate layer 41 and the second intermediate layer 42 are the same as those of the intermediate layer 40 described above, but may be different.

[0085] The FSS 20 is disposed at a distance d from the first surface 10 a, as in the first embodiment. When the radio wave transmitting body 105 according to the fifth embodiment satisfies condition A, and preferably condition B, the radio wave transmittance of the radio wave transmitting body 105 is improved compared to the radio wave transmittance of the double glazing 33 alone, as in the second embodiment.

[0086] Figure 2F is a cross-sectional view of an example of a radio wave transmitting body according to a sixth embodiment. In the sixth embodiment, the same configurations, functions, and effects as those of the above-described embodiments will not be described further by citing the above descriptions. The radio wave transmitting body 106 shown in Figure 2F has a layered structure including a double-glazing unit 34 and an FSS 20. The double-glazing unit 34 according to the sixth embodiment differs from the double-glazing unit 33 according to the fifth embodiment in that a partially decoated conductive layer 50 is disposed between the first glass plate 1 and the first intermediate layer 41.

[0087] The conductive layer 50 is provided on the double-glazing glass 34. In the illustrated example, the conductive layer 50 is a planar conductor provided on the inner surface of the first glass sheet 1. As in the third embodiment, the conductive layer 50 is a conductive layer in which gaps where no conductor is present are formed.

[0088] The FSS 20 is disposed at a distance d from the first surface 10 a, as in the first embodiment. When the radio wave transmitting body 105 according to the fifth embodiment satisfies condition A, and preferably condition C, the radio wave transmittance of the radio wave transmitting body 105 is improved compared to the radio wave transmittance of the double glazing 34 alone, as in the third embodiment.

[0089] Figure 2G is a cross-sectional view of an example of a radio wave transmitting body according to the seventh embodiment. In the seventh embodiment, the same configurations, functions, and effects as those of the above-described embodiments will not be described further by citing the above descriptions. The radio wave transmitting body 107 shown in Figure 2G has a layered structure including a double-glazing unit 35 and an FSS 20. The double-glazing unit 35 according to the seventh embodiment differs from the double-glazing unit 34 according to the sixth embodiment in that a partially decoated conductive layer 50 is disposed between the third glass plate 3 and the second intermediate layer 42.

[0090] The conductive layer 50 is provided on the double-glazing glass 35. In the illustrated example, the conductive layer 50 is a planar conductor provided on the inner surface of the third glass sheet 3. As in the third embodiment, the conductive layer 50 is a conductive layer in which spaces where no conductor is present are formed.

[0091] The FSS 20 is disposed at a distance d from the first surface 10 a, as in the first embodiment. When the radio wave transmitting body 107 according to the seventh embodiment satisfies condition A, and preferably condition C, the radio wave transmittance of the radio wave transmitting body 107 is improved compared to the radio wave transmittance of the double glazing 35 alone, as in the third embodiment.

[0092] Next, we will explain the relationship between the establishment of condition A, B, or C and the improvement in radio wave transmittance. Specifically, we will explain the formulation of the "relationship between distance d (amount of phase rotation Φ) and reactance X" that improves the radio wave transmittance compared to the substrate alone (main substrate or double glazing).

[0093] In the present disclosure, the equations defined in conditions A, B, and C are derived by regression analysis based on the following <calculation method> performed under the following <calculation conditions>.

[0094] <Calculation conditions> Type of main substrate 10: 6 types of glass plate (soda lime glass) shown in Figure 3A Type of double-glazing 30, 31, 32: 24 types of double-glazing (air as intermediate layer) shown in Figure 3B Relative permittivity of main substrate 10, first glass plate 1, and second glass plate 2: 6.8 Dielectric loss tangent of main substrate 10, first glass plate 1, and second glass plate 2: 0.02 Distance d: 0 to λ / 2 Reactance X of FSS 20: -10000Ω to +100000Ω Decoated conductive layer 50: set as a lumped constant capacitor (capacitance of 0.1 pF to 1.0 pF)

[0095] <Calculation method> Step S1: Vary the calculation conditions to extract the maximum value of the reflection coefficient Γ of the substrate alone (maximum reflection coefficient Γmax). Step S2: Extract the reactance X where the reflection coefficient Γ is smaller than the maximum reflection coefficient Γmax in the range of Φ from -π to 0 and from 0 to π, and formulate X using the regression equation of Φ.

[0096] Next, an equivalent circuit for theoretically calculating the reflection coefficient Γ will be described. The equivalent circuit for theoretically calculating the reflection coefficient Γ differs depending on the configuration through which the radio wave passes.

[0097] Fig. 4A is a cross-sectional view of the main substrate 10 alone (glass plate alone). Fig. 4B is an equivalent circuit diagram of the main substrate 10 alone (glass plate alone). According to this equivalent circuit, the reflection coefficient Γ and transmission coefficient t of the main substrate 10 alone are calculated using the equations shown in Fig. 4B.

[0098] Z ｉｎ＿ｇ１ is the input impedance from free space (air) to the first surface 10a. ｇ１ is the thickness of the main substrate 10. ２ is the transmission coefficient from the main substrate 10 to free space (air). １ is the transmission coefficient from free space (air) to the main substrate 10.

[0099] Fig. 5A is a cross-sectional view of the double-glazing unit 30 alone, and Fig. 5B is an equivalent circuit diagram of the double-glazing unit 30 alone. According to this equivalent circuit, the reflection coefficient Γ and transmission coefficient t of the double-glazing unit 30 alone can be calculated using the equations shown in Fig. 5B.

[0100] Z ｉｎ＿ｇ１ is the input impedance from the intermediate layer 40 to the first glass plate 1. Z ｉｎ＿ａｉｒ１ is the input impedance from the second glass plate 2 to the intermediate layer 40. ｉｎ＿ｇ２ is the input impedance from free space (air) to the second glass plate 2. ｇ１ is the thickness of the first glass plate 1. ａｉｒ１ is the thickness of the intermediate layer 40. ｇ２ is the thickness of the second glass plate 2. ４ is the transmission coefficient from the first glass plate 1 to free space (air). ３ is the transmission coefficient from the intermediate layer 40 to the first glass plate 1. ２ is the transmission coefficient from the second glass plate 2 to the intermediate layer 40. １ is the transmission coefficient from free space (air) to the second glass plate 2.

[0101] Fig. 6A is a cross-sectional view of a single piece of double-glazing 31, and Fig. 6B is an equivalent circuit diagram of the single piece of double-glazing 31. According to this equivalent circuit, the reflection coefficient Γ and transmission coefficient t of the single piece of double-glazing 31 are calculated using the equations shown in Fig. 6B.

[0102] Z ｉｎ＿ｇ１ is the input impedance from the conductive layer 50 to the first glass plate 1. ｉｎ＿ｄｌ is the input impedance from the intermediate layer 40 to the conductive layer 50. Z ｉｎ＿ａｉｒ１ is the input impedance from the second glass plate 2 to the intermediate layer 40. ｉｎ＿ｇ２ is the input impedance from free space (air) to the second glass plate 2. Z ｄｌ is the capacitance of the conductive layer 50. ５ is the transmission coefficient from the first glass plate 1 to free space (air). ４ is the transmission coefficient from the conductive layer 50 to the first glass plate 1. ３ is the transmission coefficient from the intermediate layer 40 to the conductive layer 50. ２ is the transmission coefficient from the second glass plate 2 to the intermediate layer 40. １ is the transmission coefficient from free space (air) to the second glass plate 2.

[0103] Fig. 7A is a cross-sectional view of a single piece of double-glazing 32, and Fig. 7B is an equivalent circuit diagram of the single piece of double-glazing 32. According to this equivalent circuit, the reflection coefficient Γ and transmission coefficient t of the single piece of double-glazing 32 are calculated using the equations shown in Fig. 7B.

[0104] Z ｉｎ＿ｇ１ is the input impedance from the intermediate layer 40 to the first glass plate 1. Z ｉｎ＿ａｉｒ１ is the input impedance from the conductive layer 50 to the intermediate layer 40. ｉｎ＿ｄｌ is the input impedance from the second glass plate 2 to the conductive layer 50. Z ｉｎ＿ｇ２ is the input impedance from free space (air) to the second glass plate 2. ５ is the transmission coefficient from the first glass plate 1 to free space (air). ４ is the transmission coefficient from the intermediate layer 40 to the first glass plate 1. ３ is the transmission coefficient from the conductive layer 50 to the intermediate layer 40. ２ is the transmission coefficient from the second glass plate 2 to the conductive layer 50. １ is the transmission coefficient from free space (air) to the second glass plate 2.

[0105] Fig. 8A is a cross-sectional view of a radio wave transmitting body 101A in which an FSS 20 is combined with a main substrate 10 alone (a glass plate alone). In the radio wave transmitting body 101A, the FSS 20 is installed in contact with the first surface 10a of the main substrate 10 alone. Fig. 8B is an equivalent circuit diagram of the radio wave transmitting body 101A. According to this equivalent circuit, the reflection coefficient Γ and transmission coefficient t of the radio wave transmitting body 101A are calculated using the equations shown in Fig. 8B.

[0106] Z ｉｎ＿ｇ１ is the input impedance from the FSS 20 to the first surface 10a. ｉｎ＿ｆｓｓ is the input impedance from free space (air) to the FSS 20. Z ｆｓｓ is the reactance X (=-10000Ω to +100000Ω) of the FSS 20. ３ is the transmission coefficient from the main substrate 10 to free space (air). ２ is the transmission coefficient from the FSS 20 to the main substrate 10. １ is the transmission coefficient from free space (air) to the FSS 20.

[0107] Fig. 9A is a cross-sectional view of a radio wave transmitting body 101B in which an FSS 20 is combined with a main substrate 10 alone (a glass plate alone). In the radio wave transmitting body 101B, the FSS 20 is installed with a space 60 provided between it and the first surface 10a of the main substrate 10 alone. Fig. 9B is an equivalent circuit diagram of the radio wave transmitting body 101B. According to this equivalent circuit, the reflection coefficient Γ and the transmission coefficient t of the radio wave transmitting body 101B are calculated using the equations shown in Fig. 9B.

[0108] Z ｉｎ＿ｇ１ is the input impedance from free space (air) to the first surface 10a. Z ｉｎ＿ａｉｒ２ is the input impedance from the FSS 20 to free space (air). ｉｎ＿ｆｓｓ is the input impedance from free space (air) to the FSS 20. ａｉｒ２ is the distance between the main substrate 10 and the FSS 20. ４ is the transmission coefficient from the main substrate 10 to free space (air). ３is the transmission coefficient from free space (air) to the main substrate 10. ２ is the transmission coefficient from the FSS 20 to free space (air). １ is the transmission coefficient from free space (air) to the FSS 20.

[0109] Fig. 10A is a cross-sectional view of a radio wave transmitting body 102A in which a single piece of double glazing 30 is combined with an FSS 20. In the radio wave transmitting body 102A, the FSS 20 is installed in contact with the first surface 10a of the single piece of double glazing 30. Fig. 10B is an equivalent circuit diagram of the radio wave transmitting body 102A. According to this equivalent circuit, the reflection coefficient Γ and transmission coefficient t of the radio wave transmitting body 102A can be calculated using the equations shown in Fig. 10B.

[0110] Z ｉｎ＿ｇ１ is the input impedance from the intermediate layer 40 to the first glass plate 1. Z ｉｎ＿ａｉｒ１ is the input impedance from the second glass plate 2 to the intermediate layer 40. ｉｎ＿ｇ２ is the input impedance from free space (air) to the second glass plate 2. Z ｉｎ＿ｆｓｓ is the input impedance from free space (air) to the FSS 20. ５ is the transmission coefficient from the first glass plate 1 to free space (air). ４ is the transmission coefficient from the intermediate layer 40 to the first glass plate 1. ３ is the transmission coefficient from the second glass plate 2 to the intermediate layer 40. ２ is the transmission coefficient from the FSS 20 to the second glass plate 2. １ is the transmission coefficient from free space (air) to the FSS 20.

[0111] Fig. 11A is a cross-sectional view of a radio wave transmitting body 102B in which a single piece of double glazing 30 is combined with an FSS 20. In the radio wave transmitting body 102B, the FSS 20 is installed with a space 60 between it and the first surface 10a of the single piece of double glazing 30. Fig. 11B is an equivalent circuit diagram of the radio wave transmitting body 102B. According to this equivalent circuit, the reflection coefficient Γ and transmission coefficient t of the radio wave transmitting body 102B can be calculated using the equations shown in Fig. 11B.

[0112] Z ｉｎ＿ｇ１is the input impedance from the intermediate layer 40 to the first glass plate 1. Z ｉｎ＿ａｉｒ１ is the input impedance from the second glass plate 2 to the intermediate layer 40. ｉｎ＿ｇ２ is the input impedance from free space (air) to the second glass plate 2. Z ｉｎ＿ａｉｒ２ is the input impedance from the FSS 20 to free space (air). ｉｎ＿ｆｓｓ is the input impedance from free space (air) to the FSS 20. ６ is the transmission coefficient from the first glass plate 1 to free space (air). ５ is the transmission coefficient from the intermediate layer 40 to the first glass plate 1. ４ is the transmission coefficient from the second glass plate 2 to the intermediate layer 40. ３ is the transmission coefficient from free space (air) to the second glass plate 2. ２ is the transmission coefficient from the FSS 20 to the second glass plate 2. １ is the transmission coefficient from free space (air) to the FSS 20.

[0113] Fig. 12A is a cross-sectional view of a radio wave transmitting body 103A in which a single piece of double glazing 31 is combined with an FSS 20. In the radio wave transmitting body 103A, the FSS 20 is installed in contact with the first surface 10a of the single piece of double glazing 31. Fig. 12B is an equivalent circuit diagram of the radio wave transmitting body 103A. According to this equivalent circuit, the reflection coefficient Γ and transmission coefficient t of the radio wave transmitting body 103A are calculated using the equations shown in Fig. 12B.

[0114] Z ｉｎ＿ｇ１ is the input impedance from the conductive layer 50 to the first glass plate 1. ｉｎ＿ｄｌ is the input impedance from the intermediate layer 40 to the conductive layer 50. Z ｉｎ＿ａｉｒ１ is the input impedance from the second glass plate 2 to the intermediate layer 40. ｉｎ＿ｇ２ is the input impedance from the FSS 20 to the second glass plate 2. ｉｎ＿ｆｓｓ is the input impedance from free space (air) to the FSS 20. ６ is the transmission coefficient from the first glass plate 1 to free space (air). ５is the transmission coefficient from the conductive layer 50 to the first glass plate 1. ４ is the transmission coefficient from the intermediate layer 40 to the conductive layer 50. ３ is the transmission coefficient from the second glass plate 2 to the intermediate layer 40. ２ is the transmission coefficient from the FSS 20 to the second glass plate 2. １ is the transmission coefficient from free space (air) to the FSS 20.

[0115] Fig. 13A is a cross-sectional view of a radio wave transmitting body 103B in which a single piece of double glazing 31 is combined with an FSS 20. In the radio wave transmitting body 103B, the FSS 20 is installed with a space 60 between it and the first surface 10a of the single piece of double glazing 31. Fig. 13B is an equivalent circuit diagram of the radio wave transmitting body 103B. According to this equivalent circuit, the reflection coefficient Γ and transmission coefficient t of the radio wave transmitting body 103B can be calculated using the equations shown in Fig. 13B.

[0116] Z ｉｎ＿ｇ１ is the input impedance from the conductive layer 50 to the first glass plate 1. ｉｎ＿ｄｌ is the input impedance from the intermediate layer 40 to the conductive layer 50. Z ｉｎ＿ａｉｒ１ is the input impedance from the second glass plate 2 to the intermediate layer 40. ｉｎ＿ｇ２ is the input impedance from free space (air) to the second glass plate 2. Z ｉｎ＿ａｉｒ２ is the input impedance from the FSS 20 to free space (air). ｉｎ＿ｆｓｓ is the input impedance from free space (air) to the FSS 20. ７ is the transmission coefficient from the first glass plate 1 to free space (air). ６ is the transmission coefficient from the conductive layer 50 to the first glass plate 1. ５ is the transmission coefficient from the intermediate layer 40 to the conductive layer 50. ４ is the transmission coefficient from the second glass plate 2 to the intermediate layer 40. ３ is the transmission coefficient from free space (air) to the second glass plate 2. ２ is the transmission coefficient from the FSS 20 to free space (air). １ is the transmission coefficient from free space (air) to the FSS 20.

[0117] Fig. 14A is a cross-sectional view of a radio wave transmitting body 104A in which a single piece of double glazing 32 is combined with an FSS 20. In the radio wave transmitting body 104A, the FSS 20 is installed in contact with the first surface 10a of the single piece of double glazing 32. Fig. 14B is an equivalent circuit diagram of the radio wave transmitting body 104A. According to this equivalent circuit, the reflection coefficient Γ and transmission coefficient t of the radio wave transmitting body 104A can be calculated using the equations shown in Fig. 14B.

[0118] Z ｉｎ＿ｇ１ is the input impedance from the intermediate layer 40 to the first glass plate 1. Z ｉｎ＿ａｉｒ１ is the input impedance from the conductive layer 50 to the intermediate layer 40. ｉｎ＿ｄｌ is the input impedance from the second glass plate 2 to the conductive layer 50. Z ｉｎ＿ｇ２ is the input impedance from the FSS 20 to the second glass plate 2. ｉｎ＿ｆｓｓ is the input impedance from free space (air) to the FSS 20. ６ is the transmission coefficient from the first glass plate 1 to free space (air). ５ is the transmission coefficient from the intermediate layer 40 to the first glass plate 1. ４ is the transmission coefficient from the conductive layer 50 to the intermediate layer 40. ３ is the transmission coefficient from the second glass plate 2 to the conductive layer 50. ２ is the transmission coefficient from the FSS 20 to the second glass plate 2. １ is the transmission coefficient from free space (air) to the FSS 20.

[0119] Fig. 15A is a cross-sectional view of a radio wave transmitting body 104B in which a single piece of double glazing 32 is combined with an FSS 20. In the radio wave transmitting body 104B, the FSS 20 is installed with a space 60 between it and the first surface 10a of the single piece of double glazing 32. Fig. 15B is an equivalent circuit diagram of the radio wave transmitting body 104B. According to this equivalent circuit, the reflection coefficient Γ and transmission coefficient t of the radio wave transmitting body 104B can be calculated using the equations shown in Fig. 15B.

[0120] Z ｉｎ＿ｇ１ is the input impedance from the intermediate layer 40 to the first glass plate 1. Z ｉｎ＿ａｉｒ１is the input impedance from the conductive layer 50 to the intermediate layer 40. ｉｎ＿ｄｌ is the input impedance from the second glass plate 2 to the conductive layer 50. Z ｉｎ＿ｇ２ is the input impedance from free space (air) to the second glass plate 2. Z ｉｎ＿ａｉｒ２ is the input impedance from the FSS 20 to free space (air). ｉｎ＿ｆｓｓ is the input impedance from free space (air) to the FSS 20. ７ is the transmission coefficient from the first glass plate 1 to free space (air). ６ is the transmission coefficient from the intermediate layer 40 to the first glass plate 1. ５ is the transmission coefficient from the conductive layer 50 to the intermediate layer 40. ４ is the transmission coefficient from the second glass plate 2 to the conductive layer 50. ３ is the transmission coefficient from free space (air) to the second glass plate 2. ２ is the transmission coefficient from the FSS 20 to free space (air). １ is the transmission coefficient from free space (air) to the FSS 20.

[0121] FIG. 16 is a plan view illustrating an equivalent circuit of an example of a conductive layer having a gap where no conductor is present. Because a conductive layer 50 such as a Low-E film has poor radio wave permeability, for example, the radio wave permeability of the conductive layer 50 can be improved by partially decoating the conductive layer 50. The capacitance of the conductive layer 50 can be adjusted by changing the line width and pitch of the decoated grid. A grid with a line width of 10 μm to 80 μm and a pitch of 1 mm to 10 mm is electrically equivalent to a capacitance of 0.1 pF to 1.0 pF. Therefore, under the above calculation conditions, the decoated conductive layer 50 is set as a lumped constant capacitor (capacitance of 0.1 pF to 1.0 pF).

[0122] Here, a method for calculating the capacitance of the conductive layer 50 in which a space where no conductor is present is formed will be described.

[0123] Fig. 17A is a plan view for explaining an example of a method for calculating the capacitance of a conductive layer having a space where no conductor is present, Fig. 17B is a cross-sectional view for explaining an example of a method for calculating the capacitance of a conductive layer having a space where no conductor is present, and Fig. 17C is a diagram showing an example of an equivalent circuit used to calculate the capacitance of a conductive layer having a space where no conductor is present.

[0124] First, an electromagnetic field simulator is used to calculate the reflection coefficient Γ of the main substrate 10 (FIGS. 17A and 17B) with the conductive layer 50 having a gap where no conductor is present. The observation plane for the reflection coefficient Γ is set to the conductive layer 50 having a gap where no conductor is present. The boundary condition in the Z-axis direction (normal direction of the first surface 10a of the main substrate 10) along which the radio waves pass through the main substrate 10 is set to "open (add space)." The boundary conditions in the X-axis and Y-axis directions parallel to the first surface 10a are set to electric or magnetic walls. However, if the boundary condition in the X-axis direction is set to an electric wall, the boundary condition in the Y-axis direction is set to a magnetic wall (or vice versa). Alternatively, the same calculation can be performed by setting both the boundary conditions in the X-axis and Y-axis directions to "unit cell."

[0125] Next, the capacitance C of the conductive layer 50 in which a gap where no conductor is present is extracted using the equivalent model shown in FIG. 17C. The capacitance C is changed as a parameter, and the capacitance that matches the reflection coefficient Γ, which is the result of calculation using an electromagnetic field simulator, is extracted as the capacitance C of the conductive layer 50 in which a gap where no conductor is present is formed. Z ｉｎ＿ｇ is the input impedance from the conductive layer 50 to the main substrate 10. Z ｉｎ＿ｄｌ is the input impedance from free space (air) to the conductive layer 50.

[0126] 18 is a diagram illustrating the positional relationship between the conductive layer in which a gap where no conductor is present and the FSS 20 in a plan view. The FSS 20 overlaps the conductive layer 50 in a plan view. It is sufficient that the FSS 20 overlaps at least a portion of the gap, such as the decoating portion 51, in a plan view.

[0127] Fig. 19 is a diagram showing the conditions under which radio wave transmission is improved for a single glass sheet, Fig. 20 is a diagram showing the conditions under which radio wave transmission is improved for double-glazing glass without a conductive layer, and Fig. 21 is a diagram showing the conditions under which radio wave transmission is improved for double-glazing glass with a conductive layer that has a gap where no conductor is present.

[0128] By performing the above calculation method for each of the configurations of "single glass sheet," "double glazing without a conductive layer," and "double glazing with a conductive layer where a gap where no conductor is present" the regression curves and regression equations shown in Figures 19, 20, and 21 are obtained. Figures 19, 20, and 21 represent the above conditions A, B, and C, respectively.

[0129] Condition A obtained from the equivalent circuit of the "single glass sheet" in Fig. 19 is included in condition B obtained from the equivalent circuit of the "double-glazing glass without a conductive layer" in Fig. 20 and condition C obtained from the equivalent circuit of the "double-glazing glass with a conductive layer in which a gap where no conductor is present" in Fig. 21. In other words, the reactance X that satisfies condition A is smaller than the reactance X that satisfies condition B or condition C when Φ is positive, and is larger than the reactance X that satisfies condition B or condition C when Φ is negative. In other words, a pair of Φ and X that satisfies condition A also satisfies condition B or condition C.

[0130] Next, the results obtained by theoretical calculation and by an electromagnetic field simulator (CST) are shown for the radio wave transmittance of the radio wave transmitting body according to each embodiment. Note that S21 is one of the S parameters using the transmission coefficient t (S21 = 20 × log １０ |t|).

[0131] FIG. 22A is a diagram showing an example of theoretical calculation results for the radio wave transmittance of the radio wave transmitting body according to the first embodiment. In the case of the main substrate 10 alone (FIGS. 4A and 4B) without the FSS 20, the reflection coefficient Γ is 0.74 and S21 is -3.6 dB. In contrast, in the case of the radio wave transmitting body 101A (FIGS. 8A and 8B) in which the main substrate 10 is combined with the FSS 20, the reflection coefficients Γ and S21 are improved compared to the case of the main substrate 10 alone. FIG. 22B is a diagram showing an example of simulation results for the radio wave transmittance of the radio wave transmitting body according to the first embodiment. According to FIG. 22B, in the case of the radio wave transmitting body 101A (FIGS. 8A and 8B) in which the main substrate 10 is combined with the FSS 20, the simulation results for the reflection coefficients Γ and S21 are almost identical to the theoretical calculation results. Note that FIGS. 22A and 22B show the case where the thickness of the main substrate 10 is 7.7 mm.

[0132] FIG. 23A is a diagram showing an example of theoretical calculation results for the radio wave transmittance of the radio wave transmitting body according to the second embodiment. In the case of a single double glazing unit 30 (FIGS. 5A and 5B) without an FSS 20, the reflection coefficient Γ is 0.93 and S21 is -10.1 dB. In contrast, in the case of a radio wave transmitting body 102A (FIGS. 10A and 10B) in which an FSS 20 is combined with a double glazing unit 30, the reflection coefficients Γ and S21 are improved compared to the case of a single double glazing unit 30. FIG. 23B is a diagram showing an example of simulation results for the radio wave transmittance of the radio wave transmitting body according to the second embodiment. According to FIG. 23B, in the case of a radio wave transmitting body 102A (FIGS. 10A and 10B) in which an FSS 20 is combined with a double glazing unit 30, the reflection coefficients Γ and S21 obtained by simulation are almost identical to the theoretical calculations. 23A and 23B show the case where the thickness of the first glass plate 1 is 4.8 mm, the thickness of the intermediate layer 40 is 18 mm, and the thickness of the second glass plate 2 is 4.8 mm.

[0133] FIG. 24A is a diagram showing an example of theoretical calculation results for the radio wave transmittance of the radio wave transmitting body according to the third embodiment. In the case of a single double-glazed glass 31 without an FSS 20 (FIGS. 6A and 6B), the reflection coefficient Γ is 0.88, and S21 is -7.7 dB. In contrast, in the case of a radio wave transmitting body 103A (FIGS. 12A and 12B) in which an FSS 20 is combined with a double-glazed glass 31, the reflection coefficients Γ and S21 are improved compared to the case of a single double-glazed glass 31. FIG. 24B is a diagram showing an example of simulation results for the radio wave transmittance of the radio wave transmitting body according to the third embodiment. According to FIG. 24B, in the case of a radio wave transmitting body 103A (FIGS. 12A and 12B) in which an FSS 20 is combined with a double-glazed glass 31, the reflection coefficients Γ and S21 obtained by simulation are almost identical to the theoretical calculations. 24A and 24B show the case where the thickness of the first glass plate 1 is 5.8 mm, the thickness of the intermediate layer 40 is 6 mm, the thickness of the second glass plate 2 is 5.8 mm, and the reactance of the conductive layer 50 is 0.5 pF.

[0134] FIG. 25A is a diagram showing an example of theoretical calculation results for the radio wave transmittance of the radio wave transmitting body according to the fourth embodiment. In the case of the double glazing 32 alone (FIGS. 7A and 7B) without the FSS 20, the reflection coefficient Γ is 0.99 and S21 is -17.4 dB. In contrast, in the case of the radio wave transmitting body 104A (FIGS. 14A and 14B) in which the double glazing 32 is combined with the FSS 20, the reflection coefficients Γ and S21 are improved compared to the case of the double glazing 32 alone. FIG. 25B is a diagram showing an example of simulation results for the radio wave transmittance of the radio wave transmitting body according to the fourth embodiment. According to FIG. 25B, in the case of the radio wave transmitting body 104A (FIGS. 14A and 14B) in which the double glazing 32 is combined with the FSS 20, the simulation results for the reflection coefficients Γ and S21 are almost the same as the theoretical calculation results. 25A and 25B show the case where the thickness of the first glass plate 1 is 4.8 mm, the thickness of the intermediate layer 40 is 18 mm, the thickness of the second glass plate 2 is 4.8 mm, and the reactance of the conductive layer 50 is 1.0 pF. 22B, 23B, 24B, and 25B show the results of infinitely repeating the FSS patterns of FIGS. 22B, 23B, 24B, and 25B. When the wavelength of the radio wave is λ, the FSS patterns are λ ２ If the above areas (areas) are repeatedly placed, the same result will be obtained.

[0135] 22A to 25B show that radio wave transmission is improved at frequencies between 3.6 GHz and 4.6 GHz, but radio wave transmission is also improved at frequencies other than 3.6 GHz and 4.6 GHz by combining the FSS 20. Radio wave transmitting bodies 101A and 101B, which combine the main substrate 10 alone (single glass plate) with the FSS 20, are shown in Figures 8B and 9B, radio wave transmitting bodies 102A and 102B, which combine the double glazing 30 alone with the FSS 20, are shown in Figures 10B and 11B, radio wave transmitting bodies 103A and 103B, which combine the double glazing 31 alone with the FSS 20, are shown in Figures 12B and 13B, and radio wave transmitting bodies 104A and 104B, which combine the double glazing 32 alone with the FSS 20, can be expressed by equivalent circuits as shown in Figures 14B and 15B. The horizontal axes in Figures 19, 20, and 21 represent the parameter Φ, which is the distance d between the first surface 10a and the FSS 20 normalized by the wavelength λ of the radio wave (Φ = θ - (4 × π × d) / λ). θ is the phase of the reflection coefficient Γ of the first surface 10a, and λ can be expressed as λ = c / f (where c is the speed of light and f is frequency). Therefore, it is clear that the conditions for improving the radio wave transparency shown in Figures 19, 20, and 21 are determined by Φ (horizontal axis) and the reactance X (vertical axis) of the FSS 20, and are not limited to a specific frequency (e.g., 3.6 GHz to 4.6 GHz). Furthermore, Figures 22A to 25B show that the specific FSS 20 patterns and the calculation results using an electromagnetic field simulator (CST) are consistent with the theory based on the equivalent circuit. At frequencies other than those shown in FIGS. 22A to 25B, the Φ and reactance X of each FSS 20 change, so a pattern of the FSS 20 having the desired Φ and reactance X must be designed.

[0136] The radio wave transmitting body according to this embodiment is preferably used at a distance from the antenna. ２ ] and λ is the wavelength of the radio wave [m], the distance [m] between the antenna and the surface material (FSS20) is preferably (2 × A / λ) or more. Here, the area A of the antenna means the area of ​​the region where the radiating elements that form the antenna are located, and if there are multiple radiating elements, it includes the area between the radiating elements.

[0137] Although the embodiments have been described above, they are presented as examples and the present invention is not limited to the above embodiments. The above embodiments can be implemented in various other forms, and various combinations, omissions, substitutions, modifications, etc. can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as set forth in the claims.

[0138] For example, the FSS 20 does not have to be fixed to a substrate (e.g., a glass plate, double glazing, etc.). The FSS 20 can be hung from a ceiling or fixed to a protrusion present around the substrate (e.g., a window frame or window sash that holds the outer edge of the window glass) so that it is installed facing the substrate. The FSS 20 can be installed in contact with the substrate, or in close proximity to the substrate without contacting it.

[0139] The FSS 20 is not limited to being arranged indoors so as to face the indoor surface of the substrate, but may also be arranged outdoors so as to face the outdoor surface of the substrate. The FSS 20 is not limited to being arranged periodically, but may also be arranged non-periodically. Even when the FSS 20 is arranged non-periodically, radio wave transparency is improved if condition A, B, or C is satisfied.

[0140] The entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2024-085733 filed on May 27, 2024 are hereby incorporated by reference as the disclosure of the present invention.

[0141] REFERENCE SIGNS LIST 1 First glass plate 2 Second glass plate 3 Third glass plate 10 Main substrate 20 FSS 21 Conductor 22 Slot 101, 102, 103, 104, 105, 106 Radio wave transmitting body 30, 31, 32, 33, 34, 35 Double glazing 40, 41, 42 Intermediate layer 50 Conductive layer 51 Deca-coating portion 60 Space

Claims

1. A glass plate having a first surface and a surface material having an array of a plurality of conductors or slots facing the first surface, wherein, where λ is the wavelength of the radio wave [m], d is the distance [m] between the first surface and the surface material, X is the reactance of the surface material [Ω], θ is the phase of the reflection coefficient of the first surface [rad], and Φ = θ - (4 × π × d) / λ, ln |X| is (0.5308 × Φ) in the range of -π < Φ < 0. ４ +3.3993 x Φ ３ +7.5554×Φ ２ +7.8195×Φ+8.9954) or greater, and in the range of 0<Φ<π, (-0.5321×Φ ４ +3.4069 x Φ ３ -7.5685 x Φ ２ +7.8267×Φ−8.9960) or less.

2. The radio wave transparent body according to claim 1, wherein the surface material has the plurality of conductors or slots arranged periodically.

3. The radio wave transmitting body according to claim 1 or 2, wherein the glass plate is a single glass plate, a laminated glass plate, a wired glass plate or a figured glass plate.

4. An architectural double glazing glass having a first surface, and a surface material having an array of a plurality of conductors or slots facing the first surface, wherein, where λ is the wavelength of the radio wave [m], d is the distance [m] between the first surface and the surface material, X is the reactance [Ω] of the surface material, θ is the phase [rad] of the reflection coefficient of the first surface, and Φ = θ - (4 × π × d) / λ, ln |X| is (0.1943 × Φ) in the range of -π < Φ < 0. ４ +1.6348 x Φ ３ +4.5737 x Φ ２ +6.0874×Φ+8.7403) or greater, and in the range of 0<Φ<π, (-0.2317×Φ ４ +1.8267 x Φ ３ -4.8632 x Φ ２ +6.2007×Φ−8.7304) or less.

5. The radio wave transmitting body according to claim 4, wherein the surface material has the plurality of conductors or slots arranged periodically.

6. The radio wave transparent body according to claim 4 or 5, wherein the double glazing has a laminated structure including a first glass plate, a second glass plate having the first surface, and an intermediate layer disposed between the first glass plate and the second glass plate, or a laminated structure including a first glass plate, a second glass plate, a third glass plate having the first surface, a first intermediate layer disposed between the first glass plate and the second glass plate, and a second intermediate layer disposed between the second glass plate and the third glass plate.

7. A double glazing unit comprising: a first surface; and a surface material facing the first surface and having an array of conductors or slots; wherein the double glazing unit includes a conductive layer having a gap formed therein where no conductors are present; where λ is the wavelength of radio waves [m], d is the distance [m] between the first surface and the surface material, X is the reactance [Ω] of the surface material, θ is the phase [rad] of the reflection coefficient of the first surface, and Φ = θ - (4 × π × d) / λ, then ln |X| is (0.0491 × Φ) in the range of -π < Φ < 0. ４ +0.8137 x Φ ３ +3.0701 x Φ ２ +5.1075×Φ+8.5746) or more, and in the range of 0<Φ<π, (-0.0511×Φ ４ +0.8285 x Φ ３ -3.1070 x Φ ２ +5.1438×Φ−8.5850) or less.

8. The radio wave transparent body according to claim 7, wherein the surface material has the plurality of conductors or slots periodically arranged.

9. The radio wave transparent body according to claim 7 or 8, wherein the double glazing has a laminated structure including a first glass plate, a second glass plate having the first surface, an intermediate layer disposed between the first glass plate and the second glass plate, and the conductive layer disposed between the first glass plate or the second glass plate and the intermediate layer, or a laminated structure including a first glass plate, a second glass plate, a third glass plate having the first surface, a first intermediate layer disposed between the first glass plate and the second glass plate, a second intermediate layer disposed between the second glass plate and the third glass plate, and the conductive layer disposed between the first glass plate and the first intermediate layer or between the second intermediate layer and the third glass plate.

10. A radio wave transparent body according to any one of claims 7 to 9, wherein the conductive layer has a capacitance of 0.1 pF or more and 1.0 pF or less.

11. A radio wave transparent body according to any one of claims 7 to 10, wherein the conductive layer is a low radiation film.

12. A surface material that can be installed to face the first surface of a glass plate, the surface material having an array of conductors or slots facing the first surface, wherein λ is the wavelength of the radio wave [m], d is the distance [m] between the first surface and the surface material, X is the reactance of the surface material [Ω], θ is the phase of the reflection coefficient of the first surface [rad], and Φ = θ - (4 × π × d) / λ, then ln |X| is (0.5308 × Φ) in the range of -π < Φ < 0. ４ +3.3993 x Φ ３ +7.5554×Φ ２ +7.8195×Φ+8.9954) or greater, and in the range of 0<Φ<π, (-0.5321×Φ ４ +3.4069 x Φ ３ -7.5685 x Φ ２ +7.8267×Φ−8.9960) or less.

13. A surface material that can be installed to face the first surface of architectural double glazing, the surface material having an array of conductors or slots facing the first surface, where λ is the wavelength of radio waves [m], d is the distance [m] between the first surface and the surface material, X is the reactance of the surface material [Ω], θ is the phase of the reflection coefficient of the first surface [rad], and Φ = θ - (4 × π × d) / λ, then ln |X| is (0.1943 × Φ) in the range of -π < Φ < 0. ４ +1.6348 x Φ ３ +4.5737 x Φ ２ +6.0874×Φ+8.7403) or greater, and in the range of 0<Φ<π, (-0.2317×Φ ４ +1.8267 x Φ ３ -4.8632 x Φ ２ +6.2007 × Φ-8.7304) or less.

14. A surface material that can be installed to face the first surface of double glazing, wherein the surface material has an array of conductors or slots facing the first surface, and the double glazing includes a conductive layer with gaps where no conductors are present, and where λ is the wavelength of radio waves [m], d is the distance [m] between the first surface and the surface material, X is the reactance [Ω] of the surface material, θ is the phase [rad] of the reflection coefficient of the first surface, and Φ = θ - (4 × π × d) / λ, then ln |X| is (0.0491 × Φ) in the range of -π < Φ < 0. ４ +0.8137 x Φ ３ +3.0701 x Φ ２ +5.1075×Φ+8.5746) or more, and in the range of 0<Φ<π, (-0.0511×Φ ４ +0.8285 x Φ ３ -3.1070 x Φ ２ +5.1438 × Φ-8.5850) or less.

Images