Frequency selection surface-mounted member

Abstract

An embodiment of the present invention pertains to a frequency selection surface loading member comprising a laminate member which includes a total of n-number (n is integer of 3 or more) of dielectric layers sequentially laminated from a first layer to a n-th layer. A frequency selection surface that allows transmission of an electrical wave of a prescribed frequency F therethrough is provided to at least one of the main surfaces of the dielectric layers forming the laminate member. The frequency selection surface has a conductive part and a nonconductive part, and has a total thickness of 1.5 mm or more.

Description

Technical Field

[0001] The present invention relates to a frequency selective surface loaded member.

Background Art

[0002] In recent years, with the increase in communication speed and communication capacity, the frequency band of radio waves used for communication has been expanding to higher frequency bands. For example, in recent fourth-generation mobile communication systems (hereinafter referred to as "4G") and fifth-generation mobile communication systems (hereinafter referred to as "5G"), radio waves in the frequency band of several hundred MHz to several tens of GHz are used.

[0003] In order to perform communication in such a high frequency band, for example, in a vehicle, it has been proposed to mount a conventional radar device in an emblem outside the vehicle or in a front grille. Furthermore, in recent years, by mounting the radar device inside the vehicle, particularly inside the windshield, communication can be performed more efficiently from a position relatively higher from the ground in the vehicle than inside the emblem or the front grille.

[0004] However, the laminated glass used for the windshield has a problem that the radio wave transmittance decreases due to reflection and absorption when radio waves pass through. Also, the radio wave transmittance varies depending on the angle of the windshield and the difference in the thickness of the glass.

[0005] The above problems can occur not only in the laminated glass of a vehicle but also in Low-E double glazing used for window glass of buildings and the like, and there is a demand for improving the radio wave transmittance with the use of high frequency bands for communication.

[0006] In response to the above problems, for example, in Patent Document 1, a method for detecting an object by an in-vehicle radar device that transmits and receives radar waves through a frequency selective surface (FSS) in a vehicle windshield and detects an object existing outside the windshield, and an in-vehicle radar system have been proposed.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] However, in a laminated member composed of a plurality of dielectric layers such as laminated glass or multilayer glass, specifically, regarding which main surface of which dielectric layer to arrange a specific FSS to improve the radio wave transmissivity, the design is not easy due to the large number of parameters to be considered and has not been clearly disclosed in the prior art.

[0009] The present invention provides a frequency selective surface loaded member having excellent radio wave transmissivity, in which a frequency selective surface is loaded on a laminated member composed of a plurality of dielectric layers.

Means for Solving the Problems

[0010] The frequency selective surface loaded member according to the present invention has a laminated member including a total of n dielectric layers laminated in order from the first layer to the nth layer (where n is an integer of 3 or more), and a frequency selective surface that transmits radio waves of a predetermined frequency F is provided on at least one of the main surfaces of the dielectric layers constituting the laminated member. The frequency selective surface has a conductive portion and a non-conductive portion, and the total thickness is 1.5 mm or more.

[0011] Further, in the frequency selective surface loaded member according to one aspect of the present invention, the frequency selective surface is provided on at least one of the two outermost surfaces of the laminated member, and the transmission phase of the frequency selective surface provided on at least one of the two outermost surfaces may be -50° to +50°.

[0012] Further, in the frequency selective surface loaded member according to one aspect of the present invention, the frequency selective surface is provided in at least one of the space between the first layer and the second layer of the laminated member and the space between the n-th layer and the (n - 1)-th layer of the laminated member, and the transmission phase of the frequency selective surface provided in at least one of the space between the first layer and the second layer of the laminated member and the space between the n-th layer and the (n - 1)-th layer of the laminated member may be -30° to +30°.

[0013] Further, in the frequency selective surface loaded member according to one aspect of the present invention, the frequency selective surface is provided in at least one of the space between the second layer and the third layer of the laminated member and the space between the (n - 1)-th layer and the (n - 2)-th layer of the laminated member (where n is an integer of 4 or more), and the transmission phase of the frequency selective surface provided in at least one of the space between the second layer and the third layer of the laminated member and the space between the (n - 1)-th layer and the (n - 2)-th layer of the laminated member may be -55° to +25°.

[0014] Further, in the frequency selective surface loaded member according to one aspect of the present invention, the frequency selective surface is provided on any two or more of the main surfaces of the dielectric layers constituting the laminated member, and the transmission phase of the frequency selective surface provided on the two or more surfaces may be -45° to +25°.

[0015] Further, in the frequency selective surface loaded member according to one aspect of the present invention, the relative permittivity of the dielectric layer of the laminated member may be 1 or more and 7.2 or less.

[0016] Further, in the frequency selective surface loaded member according to one aspect of the present invention, the relative permittivity of the dielectric layers of the first layer and the n-th layer of the laminated member may be 2.3 or more and 7.2 or less.

[0017] Further, in the frequency selective surface loaded member according to one aspect of the present invention, in a plan view, the non-conductive portions of the frequency selective surface may be formed in a double lattice stripe shape, and one unit of a quadrangle may be regularly arranged two-dimensionally without gaps.

[0018] Also, in the frequency selective surface loading member according to one aspect of the present invention, in a plan view, the conductive portions of the frequency selective surface may be formed in a double lattice stripe shape, and one unit of a square may be regularly arranged two-dimensionally without gaps.

[0019] Also, in the frequency selective surface loading member according to one aspect of the present invention, in a plan view, the shortest distance L1 between adjacent double lattices and the length L2 formed within the double lattice of the frequency selective surface may be 0.05 mm to 5 mm, and the width G of the double lattice stripe may be 0.03 mm to 1 mm.

[0020] Also, in the frequency selective surface loading member according to one aspect of the present invention, in a plan view, a plurality of ring-shaped non-conductive portions may be formed on the frequency selective surface.

[0021] Also, in the frequency selective surface loading member according to one aspect of the present invention, the distances between the centers of adjacent ring-shaped non-conductive portions of the plurality of ring-shaped non-conductive portions may all be equal.

[0022] Also, in the frequency selective surface loading member according to one aspect of the present invention, the sheet resistance of the conductive portion of the frequency selective surface may be 50 Ω / square or less.

[0023] Also, in the frequency selective surface loading member according to one aspect of the present invention, the conductive portion of the frequency selective surface may contain at least one selected from the group consisting of Ag, ITO, tin oxide doped with at least one of fluorine and antimony, and Cu.

[0024] Also, in the frequency selective surface loading member according to one aspect of the present invention, the non-conductive portion of the frequency selective surface may contain at least one selected from PVB, EVA, and air.

[0025] Also, in the frequency selective surface loading member according to one aspect of the present invention, the radio wave of the frequency F may be included in the range of 1 GHz to 100 GHz.

[0026] In addition, in the frequency selective surface loading member according to one aspect of the present invention, the radio wave of the frequency F may be a vertically polarized wave or a horizontally polarized wave incident at an incident angle of 0° to 80°.

[0027] In addition, in the frequency selective surface loading member according to one aspect of the present invention, the radio wave of the frequency F may be a vertically polarized wave or a horizontally polarized wave incident at an incident angle of 60° to 70°.

Advantages of the Invention

[0028] According to the present invention, it is possible to provide a frequency selective surface loading member excellent in radio wave permeability, in which a frequency selective surface is loaded on a laminated member composed of a plurality of dielectric layers.

Brief Description of the Drawings

[0029]

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DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, embodiments of the present invention will be described in detail. In the following drawings, members and parts having the same function may be denoted by the same reference numerals, and redundant descriptions may be omitted or simplified. In addition, the embodiments shown in the drawings are schematic for clearly explaining the present invention, and do not necessarily accurately represent the size and scale of an actual product.

[0031] In this specification, the "laminated member" means a laminate in which a plurality of dielectric layers are laminated, and has a configuration that does not include a frequency selective surface. On the other hand, the "frequency selective surface loading member" has a configuration in which a frequency selective surface is loaded on at least one of the main surfaces of the plurality of dielectric layers constituting the laminated member. Thus, in this specification, the "laminated member" and the "frequency selective surface loading member" are distinguished by a configuration including a frequency selective surface and a configuration not including it.

[0032] The frequency selective surface loaded member according to this embodiment (hereinafter also referred to as the FSS loaded member) has a laminated member including a total of n dielectric layers laminated in order from the first layer to the nth layer (where n is an integer of 3 or more). And a frequency selective surface (hereinafter also referred to as FSS) that transmits radio waves of a predetermined frequency F is provided on at least one of the main surfaces of the plurality of dielectric layers constituting the laminated member. The FSS has a conductive portion and a non-conductive portion, and the total thickness of the FSS loaded member is 1.5 mm or more.

[0033] Thus, the FSS loaded member according to this embodiment is based on finding certain indicators regarding the characteristics of the FSS whose radio wave transmissivity is improved when the FSS that transmits radio waves of a predetermined frequency F is loaded on a laminated member including a plurality of dielectric layers, and the loading surface of the FSS, with the total thickness of such an FSS loaded member being within a specific range or more.

[0034] FIG. 1 is a cross-sectional view showing the structure of the FSS loaded member according to this embodiment. As shown in FIG. 1, the FSS loaded member 10 has a laminated member including a total of n dielectric layers laminated in order from the first layer to the nth layer. In other words, in such a laminated member, the dielectric layer located on one of the outermost surface sides is the first layer, and among the two main surfaces of the first layer, the second layer to the nth layer are laminated in order on the main surface side opposite to the outermost surface of the laminated member. Further, the laminated member in the FSS loaded member 10 is composed of three or more dielectric layers. That is, n is an integer of 3 or more.

[0035] In the FSS loaded member according to this embodiment, an FSS that transmits radio waves of a predetermined frequency F is provided on at least one of the main surfaces of the plurality of dielectric layers constituting the laminated member. Such an FSS has a function of selectively transmitting radio waves of a preset frequency F.

[0036] Here, "in the FSS loaded member according to this embodiment, an FSS is provided on at least one of the main surfaces of the plurality of dielectric layers constituting the laminated member" means that an FSS is provided on at least one of the main surfaces among all the main surfaces of the plurality of dielectric layers constituting such a laminated member.

[0037] For example, when the laminated member includes a total of three dielectric layers (n = 3), the main surfaces of such a laminated member are a total of four: the outermost surface on the first layer side, the main surface between the first layer and the second layer, the main surface between the second layer and the third layer, and the outermost surface on the third layer side. When the main surfaces overlap, the number of main surfaces shall be counted as one. Therefore, in this case, the FSS-loaded member has the FSS provided on at least one of these four main surfaces of the laminated member.

[0038] The FSS-loaded member 10 in the present embodiment may be provided such that, in a plan view, the outer edge of the FSS is located inside the outer edge of the FSS-loaded member 10. That is, the FSS-loaded member 10 may be provided with a specific region that improves the transmissivity of radio waves of frequency F.

[0039] Note that the plan view corresponds to the case of viewing from the normal direction of the main surface of the FSS-loaded member 10. For example, in FIG. 2, the case where the FSS-loaded member 10 is a window member for a vehicle is illustrated, but the FSS-loaded member 10 according to the present embodiment may have a first region A including the FSS and a second region B not including the FSS in a plan view.

[0040] Note that the FSS-loaded member 10 shown in FIG. 2 shows the case where the outer edge of the first region A is inside the outer edge of the second region B, but in the plan view of the FSS-loaded member 10, a form in which a part of the outer edge of the first region A shares or overlaps a part of the outer edge of the second region B may also be used.

[0041] Alternatively, the FSS-loaded member according to the present embodiment may be provided such that, in a plan view, the outer edge of the FSS substantially coincides with the outer edge of the laminated member. That is, in the FSS-loaded member according to the present embodiment, the sizes of the FSS and other dielectric layers may be substantially the same.

[0042] Also, when the FSS-loaded member 10 according to the present embodiment is a windshield of a vehicle, the first region A may be provided in a position that does not block the driver's view, such as near the upper center (FIG. 2) or the lower part of the FSS-loaded member in a plan view.

[0043] Here, when the vertical length of the vehicle windshield is "D", for example, the "upper part" can exemplify the area up to a distance of 0.3×D or less from the upper edge of the windshield, and the "lower part" can exemplify the area up to a distance of 0.3×D or less from the lower edge of the windshield.

[0044] Also, the "upper part" may be the area up to a distance of 0.2×D or less from the upper edge of the windshield, and the "lower part" may be the area up to a distance of 0.2×D or less from the lower edge of the windshield.

[0045] Furthermore, when the FSS loading member 10 according to this embodiment is a vehicle windshield, if the driver's field of view can be sufficiently maintained, the FSS loading member 10 may be provided not only in a partial area of the windshield but also over the entire surface. At least, the FSS loading member is preferably provided in an area where transmission and reception of radio waves of a predetermined frequency F can be ensured.

[0046] In addition, when the FSS loading member 10 according to this embodiment is used as a vehicle window member, it may be used not only for the windshield but also for resin aerodynamic parts such as rear glass, side glass, rear quarter glass, roof glass, resin doors and resin roofs, and rear spoilers.

[0047] The total thickness of the FSS loading member according to this embodiment is preferably 1.5 mm or more, more preferably 2.0 mm or more, and still more preferably 4.0 mm or more for reasons such as ease of handling and easy retention of predetermined strength. Here, the total thickness of the FSS loading member refers to the thickness of the FSS loading member in the area where FSS is loaded in plan view.

[0048] Also, although there is no particular limitation on the total thickness of the FSS loading member according to this embodiment, it is preferably 40 mm or less, more preferably 30 mm or less for reasons such as an increase in the weight of the FSS loading member.

[0049] When the total thickness of the FSS loading member according to this embodiment is 1.5 mm or more, when radio waves with a frequency F in the range of 1 GHz to 100 GHz pass through the FSS loading member, the wavelength of the frequency F and the total thickness of the FSS loading member are on the same scale. Therefore, the FSS loading member can improve the radio wave transmissivity by designing the FSS loading surface and the specific FSS shape in consideration of the interference of reflected waves at a plurality of interfaces in the laminated member.

[0050] On the other hand, if the lamination mode of the FSS on the dielectric member or the design of the FSS in the FSS loading member is inappropriate, the radio wave transmissivity may not be improved. However, the FSS transmission member according to this embodiment has found the arrangement position of the FSS provided in the laminated member, the transmission phase of the FSS, and the appropriate shape of the FSS in order to realize excellent radio wave transmissivity.

[0051] Hereinafter, each member of the FSS loading member according to this embodiment will be described in more detail.

[0052] <Dielectric layer> The dielectric layer is a substance with superior dielectric properties than conductivity, and refers to a substance that has the property of being electrically polarized when an external electric field is applied. The type of dielectric layer included in the FSS loading member is not particularly limited, and examples include dielectric substrates such as glass substrates and resin substrates, intermediates provided between dielectric substrates, coating layers, coating layers provided on the surface of the dielectric substrate (the outermost surface side of the FSS loading member), air, and the like. When the dielectric layer is air, the air is limited to any one of the second layer to the n-1th layer, and can be used as the dielectric layer between dielectric substrates, particularly the dielectric layer between glass substrates.

[0053] As the glass substrate, for example, soda lime glass, alkali-free glass, borosilicate glass, quartz glass, etc. can be used. A strengthened glass substrate subjected to physical strengthening treatment or chemical strengthening treatment may be used for the glass substrate. The glass substrate is preferably float glass produced by the float method. The glass substrate may also be glass produced by the fusion method.

[0054] Examples of the resin substrate include substrates made of acrylic resins such as polymethyl methacrylate, aromatic polycarbonate resins such as polyphenylene carbonate, and aromatic polyester resins such as polyethylene terephthalate (PET).

[0055] As an intermediate provided between dielectric substrates, for example, between glass substrates, a resin layer containing a resin material such as polyvinyl butyral (PVB), ethylene vinyl acetal (EVA), or polyethylene terephthalate (PET) can be used.

[0056] Also, as the intermediate, a thermosetting resin that is liquid before heating may be used. That is, the intermediate only needs to be in a layered state when it is a laminated member, and the intermediate may be liquid in the state before joining dielectric substrates and the like.

[0057] Furthermore, as the intermediate, air (vacuum) may be used as exemplified above, or it may contain at least one selected from PVB, EVA, or air. And the non-conductive portion of the FSS may contain at least one selected from PVB, EVA, or air.

[0058] In the FSS loading member according to the present embodiment, the intermediate may have a plurality of layers. In this specification, when having a total of m layers of intermediate, they are referred to as the first intermediate, the second intermediate, ···, the m-th intermediate. However, m is an integer of 1 or more and n - 2 or less.

[0059] Examples of the coating layer include functional coating layers having various functions, such as a light-shielding layer such as a black ceramics layer, a coating layer that imparts a water-repellent function, a hydrophilic function, an anti-fogging function, etc., and a heat-ray reflecting layer. Examples of these coating layers include layers having a thickness thinner than that of the dielectric substrate and layers made of a material having less rigidity than that of the dielectric substrate. The coating layer is often arranged, for example, to coat the main surface of a dielectric substrate made of a glass substrate having a predetermined thickness and high rigidity.

[0060] The coating layer can be formed using a physical vapor deposition method such as sputtering, vacuum evaporation, or ion plating. The coating layer may also be formed using a chemical vapor deposition method or a wet coating method.

[0061] In the FSS-loaded member according to the present embodiment, a normal dielectric substrate is often used for the outermost dielectric layer (at least one of the first layer and the nth layer). In particular, when the FSS-loaded member according to the present embodiment is used as an automotive laminated glass, the first layer and the nth layer are preferably made of a glass substrate.

[0062] However, when a coating layer such as a black ceramic layer is provided on the second layer or the (n-1)th layer as the first layer or the nth layer of the FSS-loaded member according to the present embodiment, it may be a coating layer. Note that a coating layer such as a black ceramic layer is a layer that shields visible light and is also referred to as a shielding layer.

[0063] When the shielding layer is used as the outermost layer of the dielectric layer of the FSS-loaded member in this way, the design can be improved, particularly when it is used as an automotive laminated glass. Further, when the FSS-loaded member is an automotive laminated glass and the FSS overlaps at least a part of the shielding layer in a plan view, it is preferable that the FSS is difficult to be visually recognized, and it is more preferable that the FSS overlaps the entire shielding layer.

[0064] When the outermost layer (the first layer or the nth layer) of the dielectric layer is a shielding layer, the dielectric layer (the second layer or the (n-1)th layer) adjacent to the shielding layer is preferably a glass substrate. Further, the intermediate body is used for any of the second layer to the (n-1)th layer other than the outermost dielectric layer (other than the first layer and the nth layer).

[0065] The shape of the dielectric layer is not particularly limited and may be planar or may be a curved surface shape in which the main surface has a finite radius of curvature and is curved.

[0066] The relative permittivity of the dielectric layer is preferably 1 or more, more preferably 2.3 or more. Also, the relative permittivity of the dielectric layer is preferably 7.2 or less, more preferably 7.0 or less, and even more preferably 6.8 or less. The relative permittivity of the dielectric layer is a value obtained at 1 MHz using a dielectric breakdown test apparatus in a test environment where the temperature is maintained within the range of 23°C ± 2°C and the relative humidity is maintained within the range of 50% ± 5% RH in accordance with the transformer bridge method based on ASTM D150.

[0067] The relative permittivity of the first layer and the nth layer of the dielectric layer is preferably 2.3 or more. Also, the relative permittivity of the first layer and the nth layer of the dielectric layer is preferably 7.2 or less, more preferably 7.0 or less, and even more preferably 6.8 or less.

[0068] In particular, for at least one of the first layer to the nth layer of the dielectric layer of the FSS loading member according to the present embodiment, it is preferable that its relative permittivity is a value close to the relative permittivity of the adjacent dielectric layer. Thereby, reflection at the interface between the dielectric layers can be reduced, improving the radio wave transmissivity.

[0069] As the dielectric layer in the FSS loading member, at least one layer may use a glass substrate. The composition of the glass substrate is not particularly limited. For example, when using soda-lime glass as the glass substrate, in terms of the molar percentage representation based on oxides of each component, 50% ≦ SiO 2 ≦ 80% 0.1% ≦ Al 2 O 3 ≦ 25% 3% ≦ R 2 O ≦ 30% (R 2 O is the total amount of Li 2 O, Na 2 O, K 2 O) 0% ≦ B 2 O 3 ≦ 10% 0% ≦ MgO ≦ 25% 0% ≦ CaO ≦ 25% 0% ≦ SrO ≦ 5% 0% ≦ BaO ≦ 5% 0% ≦ ZrO 2 ≦ 5% 0% ≤ SnO 2 ≤ 5% Satisfying this condition are listed.

[0070] Also, when using a non-alkali glass as the glass substrate for the FSS loading member, the content in terms of molar percentage based on oxides of each component is 50% ≤ SiO 2 ≤ 80% 0% ≤ Al 2 O 3 ≤ 30% 0% ≤ B 2 O 3 ≤ 25% 0% ≤ MgO ≤ 25% 0% ≤ CaO ≤ 25% 0% ≤ SrO ≤ 25% 0% ≤ BaO ≤ 25% 0% ≤ ZrO 2 ≤ 5% 5% ≤ RO ≤ 40% (RO represents the total amount of MgO, CaO, SrO, and BaO) Satisfying this condition are listed.

[0071] Furthermore, as the glass substrate, borosilicate glass, which is an oxide-based glass with silicon dioxide as the main component and containing a boron component, may be used. The boron component in the borosilicate glass is boron oxide (a general term for boron oxides such as boric anhydride (B 2 O 3 ), etc.), and the proportion of boron oxide in the glass is expressed in terms of B 2 O 3 conversion. The main components in the glass are, similarly, SiO 2 , Al 2 O 3 , B 2 O 3 , MgO, CaO, SrO, BaO, LiO 2 , Na 2 O, K 2 O, etc., expressed as oxides, and the proportion is expressed based on oxides.

[0072] In this embodiment, the borosilicate glass has 1.0% or more of B in terms of molar percentage based on oxides 2O 3 Refers to an oxide-based glass mainly composed of silicon dioxide and containing O.

[0073] The specific gravity of the glass substrate is preferably 2.4 or more and 3.0 or less. Also, the Young's modulus of the glass substrate is preferably 60 GPa or more and 100 GPa or less.

[0074] The average coefficient of thermal expansion of the glass substrate from 50°C to 350°C is preferably 50×10 -7 / °C or more. Also, the average coefficient of thermal expansion of the glass substrate from 50°C to 350°C is preferably 120×10 -7 / °C or less. If the glass substrate satisfies these physical property requirements, it can be used very suitably, for example, as a window material or the like.

[0075] <Frequency Selective Surface> The frequency selective surface (FSS) has a conductive part and a non-conductive part in a plan view, transmits radio waves of a predetermined frequency F, and suppresses the transmission of radio waves of other frequencies outside that frequency band.

[0076] Here, the conductive part in the FSS refers to the part of the FSS having a sheet resistance of 50 Ω / □ or less at 20°C. Also, the non-conductive part in the FSS refers to the part of the FSS having a sheet resistance exceeding 50 Ω / □ at 20°C.

[0077] Also, in the FSS, the difference in sheet resistance at 20°C between the conductive part and the non-conductive part may be 50 Ω / □ or more, preferably 100 Ω / □ or more, and more preferably 1000 Ω / □ or more.

[0078] The material constituting the conductive part of the FSS is not particularly limited. For example, materials containing at least one of Ag, indium tin oxide (ITO), Cu, Al, fluorine and antimony-doped tin oxide (SnO 2 :F,Sb), titanium nitride, niobium nitride, chromium nitride, zirconium nitride, hafnium nitride and other metals can be mentioned.

[0079] Among them, it is preferable to include at least one selected from the group consisting of tin oxide (SnO 2 :F,Sb) doped with at least one of Ag, ITO, fluorine, and antimony, and Cu. The non-conductive portion may be, for example, a dielectric material constituting the dielectric layer or air.

[0080] The sheet resistance of the conductive portion of the FSS in the present embodiment is preferably 50 Ω / sq or less, more preferably 30 Ω / sq or less, and even more preferably 10 Ω / sq or less. When the sheet resistance of the conductive portion is within the above range, the conductive and non-conductive portions of the FSS function effectively as an inductor or a capacitor, thereby improving the radio wave transmissivity.

[0081] The sheet resistance of the conductive portion of the FSS can be measured, for example, using a non-contact eddy current method resistance value measuring instrument 717 conductance monitor manufactured by DELCOM.

[0082] The shape of the FSS in plan view is not particularly limited. As a specific example, the shape of the FSS in the present embodiment in plan view (XY plane) will be described below with reference to FIGS. 3(A) to 3(C), but the shape of the FSS is not limited thereto.

[0083] First, the FSS 30a shown in FIG. 3(A) has a conductive portion 31a and a non-conductive portion 32a, and in plan view, the non-conductive portion 32a is formed in a double lattice stripe shape.

[0084] Here, the double lattice stripe shape refers to a lattice stripe formed by a plurality of double vertical lines and a plurality of double horizontal lines intersecting each other. In other words, the double lattice stripe shape means a shape in which the non-conductive portion 32a is formed in a double lattice stripe shape consisting of line segments along the X-axis direction and the Y-axis direction perpendicular to the X-axis with respect to the conductive portion 31a.

[0085] In such a shape, since a single repeating unit A is constituted by a plurality of dimensional parameters, there is an advantage of high design freedom. The FSS30a shown in Fig. 3(A) is composed of a pattern in which a square single unit A (basic pattern) consisting of a conductive part 31a and a non-conductive part 32a is regularly arranged two-dimensionally in the X-axis direction and the Y-axis direction without gaps.

[0086] In the FSS30a shown in Fig. 3(A), the square single unit A may be a square with equal side lengths or a rectangle with different side lengths. Also, the length L1 of one side in the Y-axis direction of the conductive part 31a of the square formed between adjacent double gratings (the shortest distance between adjacent double gratings in the Y-axis direction), the length L2 of the conductive part 31a formed within the double grating in the Y-axis direction, and the width G of the non-conductive part 32a forming the double grating stripes can be set as appropriate.

[0087] L1 and L2 are preferably 0.05 mm to 5 mm, and the width G is preferably 0.01 mm to 0.5 mm. In Fig. 3(A), the length L1, the length L2, and the width G of the FSS are all shown as the length or width in the Y-axis direction, but for each of the above dimensions in the X-axis direction, the above preferred numerical ranges may be used.

[0088] Also, the loading area of the FSS30a in the FSS loading member can be set as appropriate. However, when the wavelength in air corresponding to the frequency F of the transmitted radio wave is λ (mm), it is preferably λ 2 mm 2 or more, more preferably 2λ 2 mm 2 or more, and even more preferably 3λ 2 mm 2 or more.

[0089] Also, the width G of the non-conductive part 32a is more preferably 250 μm or less, and even more preferably 200 μm or less. The width G of the non-conductive part 32a is preferably 10 μm to 250 μm, and more preferably 10 μm to 200 μm. When the width G of the non-conductive part 32a is within the above range, the electric field is concentrated in the non-conductive part 32a and effectively acts as a capacitance, thereby improving the radio wave permeability.

[0090] As another shape of the FSS, the FSS 30b shown in FIG. 3(B) has a conductive portion 31b and a non-conductive portion 32b, and in a plan view, the conductive portion 31b is formed in a double lattice stripe shape. In other words, the conductive portion 31b is formed in a double lattice stripe shape composed of stripes along the X-axis direction and the Y-axis direction perpendicular to the X-axis. This is a shape in which the conductive portion 31a and the non-conductive portion 32a are interchanged in the shape of the FSS 30a in the FSS loading member shown in FIG. 3(A) above.

[0091] In such a shape, since a single unit A of repetition is constituted by a plurality of dimensional parameters, there is an advantage that the degree of freedom in design is high. The single unit A of a quadrangle may be a square with equal side lengths or a rectangle with different lengths of two sides.

[0092] Also, the length of one side in the Y-axis direction of the quadrangular non-conductive portion 32b formed between adjacent double lattices (the shortest distance between adjacent double lattices in the Y-axis direction) L1, the length L2 in the Y-axis direction of the non-conductive portion 32b formed within the double lattice, and the length of the width G of the conductive portion 31b forming the double lattice stripe can be set as appropriate. L1 and L2 are preferably 0.01 mm to 10 mm, and the width G is preferably 0.03 mm to 1 mm.

[0093] In addition, in FIG. 3(B), the length L1, the length L2, and the width G of the FSS are all shown as the length or width in the Y-axis direction, but for each of the above dimensions in the X-axis direction, the above preferable numerical range may be sufficient.

[0094] Also, the loading area of the FSS 30b in the FSS loading member can be set as appropriate, but when the wavelength in the air corresponding to the frequency F of the radio wave to be transmitted is λ (mm), λ 2 mm 2 or more is preferable, 2λ 2 mm 2 or more is more preferable, and 3λ 2 mm 2 or more is even more preferable.

[0095] As another shape of the FSS, the FSS30c shown in Fig. 3(C) has a conductive portion 31c and a non-conductive portion 32c, and in a plan view, it has a circular loop slot shape in which a plurality of ring-shaped non-conductive portions 32c are formed. In the FSS30c having such a shape, the hexagon constituting part A includes a pattern in which the hexagons are regularly arranged in a triangular pattern (along the XY plane) without gaps so as to share each side of the hexagon, thereby efficiently filling the circular loop slot. The FSS30c shown in Fig. 3(C) has an advantage that the slot pitch can be made smaller than that of the square arrangement such as the FSS30a shown in Fig. 3(A), so that the degree of design freedom can be increased.

[0096] Among the above-mentioned part A in the FSS30c of Fig. 3(C), the length p from each vertex of the hexagon to the center (centroid), the radius t of the virtual circle c passing through the center of the width W of the ring-shaped non-conductive portion 32c, and the width W of the ring-shaped non-conductive portion 32c can be appropriately set. The radius t is shorter than the length p, and the width W is shorter than the length p.

[0097] The length p is preferably 0.25 mm to 3 mm, t is preferably 0.3 mm to 1.5 mm, and the width W is preferably 0.03 mm to 1 mm. Also, the loading area of the FSS30c in the FSS loading member can be appropriately set. However, when the wavelength in the air corresponding to the frequency F of the transmitted radio wave is λ (mm), λ 2 mm 2 or more is preferable, 2λ 2 mm 2 or more is more preferable, and 3λ 2 mm 2 or more is even more preferable.

[0098] Also, the width W of the non-conductive portion is more preferably 250 μm or less, and even more preferably 200 μm or less. The width W is more preferably 30 μm to 250 μm, and even more preferably 30 μm to 200 μm. When the width W of the non-conductive portion is within the above range, the electric field is concentrated in the non-conductive portion and effectively acts as a capacitance, so that the radio wave transmissivity is improved.

[0099] In the FSS 30c shown in (C) of FIG. 3, the ring-shaped non-conductive portion 32c can appropriately set the length p, radius t, and width W in each individual portion A within the above numerical ranges. Also, the non-conductive portion 32c may be designed such that the distances between the centers of adjacent ring-shaped non-conductive portions are all equal. In other words, in a plan view, taking the regular hexagonal portion A composed of the conductive portion 31c and the non-conductive portion 32c as one unit, such a regular hexagonal portion A may have a circular loop slot shape composed of the ring-shaped non-conductive portion 32c having the same center as the center of the regular hexagon and formed inside the regular hexagon, and the other conductive portion 31c.

[0100] Note that when the FSS loading member according to the present embodiment has a plurality of FSSs, the FSS loading member can be designed by arbitrarily combining the FSS shape patterns in the plan view described above for each FSS.

[0101] The thickness of the FSS is not particularly limited, but from the viewpoint of improving the radio wave transmissivity, it is preferably 0.1 mm or less, more preferably 0.05 mm or less, and even more preferably 0.02 mm or less. Also, the thickness of the FSS may be 0.003 μm or more from the viewpoint of the stability of the conductive portion as a film, preferably 0.005 μm or more, and more preferably 0.010 μm or more.

[0102] The FSS selectively transmits radio waves of a predetermined frequency F. As the predetermined frequency F transmitted through the FSS loading member, it is preferably included in the range of 1 GHz to 100 GHz.

[0103] Also, from the viewpoint that radio waves of the frequency F are likely to improve the radio wave transmissivity of the FSS loading member by the FSS, it is more preferably 10 GHz or more, and even more preferably 20 GHz or more.

[0104] Also, the upper limit of the frequency F is not particularly limited, and for example, it may be 90 GHz or less, or 80 GHz or less. For example, in the case of laminated glass for vehicles, the attenuation of the radio wave with a frequency F of 10 GHz or more tends to increase, and it is effective to improve the radio wave transmissivity by loading the FSS for radio waves with a frequency F of 10 GHz or more.

[0105] Hereinafter, a preferable loading mode of the FSS in the FSS-loaded member according to the present embodiment will be described. In the FSS-loaded member according to the present embodiment, the FSS is provided on at least one of the main surfaces of the dielectric layer constituting the laminated member. By designing the FSS-loaded member so that the transmission phase of the FSS in the case of providing the FSS on a specific main surface falls within a specific range, the radio wave transmissivity can be improved. When the FSS-loaded member according to the present embodiment has a plurality of FSSs, the FSS-loaded member can be designed by arbitrarily combining the loading patterns described below for each FSS.

[0106] Here, the transmission phase (φ21) of the FSS is the transmission phase (deg) when the radio wave passes through the FSS, and represents the amount of phase change when the radio wave passes through the FSS. The transmission phase of the FSS can be derived by calculation, for example, using the finite element method software HighFrequencyStructureSimulator (HFSS) manufactured by Ansys, Inc. in the United States.

[0107] Here, the transmission phase (φ21) of the FSS can determine the configuration of the laminated member, the shape of the FSS, and the loading position of the FSS according to the incident angle of the radio wave with the frequency F on the FSS-loaded member. In particular, for the FSS-loaded member according to the present embodiment, the incident angle of the radio wave with the frequency F can be appropriately set within the range of 0° to 80°. Further, the incident angle of the radio wave with the frequency F on the FSS-loaded member can be appropriately set according to, for example, the range of 0° to 70°, the range of 20° to 70°, the range of 35° to 70°, and further the range of 60° to 70°.

[0108] Furthermore, the incident angle of the radio wave of frequency F with respect to the FSS loading member is an angle other than the incident angle of 0°, and can be designed according to the vertical polarization wave (TM wave) or the horizontal polarization wave (TE wave) of the incident radio wave, for example, in the range of 20° to 70°. For example, when the FSS loading member is a window glass for a vehicle, particularly a windshield, the angle of the windshield with respect to the radio wave of frequency F incident parallel to the horizontal plane is often about 67.5°, and in the range of the incident angle of 60° to 70°, it is preferable to design so that the transmission characteristics (S21) are improved according to the vertical polarization wave or the horizontal polarization wave of the incident radio wave.

[0109] In the FSS loading member according to the present embodiment, when the FSS is provided on at least one of the two outermost surfaces of the laminated member, the transmission phase of at least one of the FSSs is preferably -50° to +50°. That is, when the FSS is provided on at least one of the outermost surface a on the first layer side and the outermost surface b on the nth layer side of the FSS loading member 40 shown in FIG. 4, the transmission phase of at least one of the FSSs is preferably -50° to +50°. Both the outermost surface a and the outermost surface b are positions where the radio wave of frequency F first passes when it enters the first dielectric layer.

[0110] Since the transmission phase of the FSS provided at such a position is -50° to +50°, the reflected waves from each surface of the FSS loading member can be canceled and the reflection can be reduced, so that the radio wave transmissivity is improved. Further, in the FSS loading member according to the present embodiment, when the FSS is provided on both of the two outermost surfaces of the laminated member, the transmission phases of both of the FSSs are preferably -50° to +50°.

[0111] The transmission phase of the FSS provided on at least one of the two outermost surfaces of the laminated member is preferably -45° or more, more preferably -40° or more. In this case, the transmission phase of the FSS is preferably 45° or less, more preferably 40° or less. Furthermore, in the FSS loading member according to the present embodiment, when the FSS is provided on both of the two outermost surfaces of the laminated member, it is also preferable to set it within the above preferable range.

[0112] Also, when the incident angle of the radio wave with frequency F on the FSS loading member is 55° or more, the relative dielectric constant of the first layer and the nth layer of the laminated member of the FSS loading member is 4 to 7, and the thickness is 1 mm to 4 mm, the transmission phase of such FSS is preferably -40° or more, more preferably -30° or more. Also, the transmission phase of such FSS is preferably 40° or less, more preferably 30° or less. Here, the incident angle means the angle of the incident direction of the radio wave with frequency F from the normal of the main surface of the FSS loading member.

[0113] In the FSS loading member according to the present embodiment, as shown in FIG. 5, consider the case where the FSS is provided in at least one of a between the first layer and the second layer of the laminated member and b between the nth layer and the (n - 1)th layer of the laminated member. At this time, in the FSS loading member according to the present embodiment, the transmission phase of at least one of the FSS is preferably -30° to +30°.

[0114] Both a and b correspond to the locations where the radio wave with frequency F passes before entering the layer (the second layer or the (n - 1)th layer) located second from the outermost layer after passing through the outermost layer (the first layer or the nth layer) of the laminated member. Since the transmission phase of the FSS provided at such a position is -30° to +30°, the reflected waves from each surface of the FSS loading member can be canceled and the reflection can be reduced, thus improving the radio wave transmissivity. Also, in the FSS loading member according to the present embodiment, when the FSS is provided in both of the two layer interfaces of the laminated member, the transmission phases of both of the FSS are preferably -30° to +30°.

[0115] The transmission phase of the FSS provided in at least one of a between the first layer and the second layer of the laminated member and b between the nth layer and the (n - 1)th layer of the laminated member is preferably -29° or more, more preferably -28° or more, and even more preferably -26° or more. Also, in this case, the transmission phase of the FSS is preferably 29° or less, more preferably 26° or less, and even more preferably 23° or less.

[0116] Further, under the conditions that the incident angle of the radio wave with frequency F is 55° or more, the relative dielectric constant of the first layer and the nth layer of the FSS loading member is 4 to 7, the thickness is 1 mm to 4 mm, the relative dielectric constant of the second layer and the (n - 1)th layer is 1 to 7, and the thickness is 0.3 mm to 1.6 mm, the transmission phase of such FSS is preferably -30° or more, more preferably -20° or more, and even more preferably -15° or more.

[0117] Also, the transmission phase of the FSS under the same conditions is preferably 15° or less, more preferably 10° or less, and even more preferably 5° or less. Furthermore, in the FSS loading member according to the present embodiment, when the FSS is provided on both a between the first layer and the second layer and b between the nth layer and the (n - 1)th layer of the laminated member, it may be set within the above preferable range.

[0118] In the FSS loading member according to the present embodiment, as shown in FIG. 6, when the FSS is provided in at least one of a between the second layer and the third layer and b between the (n - 1)th layer and the (n - 2)th layer of the laminated member, the transmission phase of at least one of the FSSs is preferably -55° to +25°. However, in this case, n is an integer of 4 or more.

[0119] Both a and b correspond to locations where the radio wave with frequency F passes through the layer (the second layer or the (n - 1)th layer) located second from the outermost layer (the first layer or the nth layer) and then enters the layer (the third layer or the (n - 2)th layer) located third from the outermost layer before passing. Since the transmission phase of the FSS provided at such locations is -55° to +25°, the reflected waves from each surface of the FSS loading member can be canceled and the reflection can be reduced, thereby improving the radio wave transmissivity.

[0120] Also, in the FSS loading member according to the present embodiment, when the FSS is provided on both of the two outermost surfaces of the laminated member, the transmission phases of both of the FSSs are preferably -55° to +25°.

[0121] The transmission phase of the FSS provided in at least one of a between the second layer and the third layer of the laminated member and b between the (n-1)th layer and the (n-2)th layer of the laminated member is preferably -53° or more, more preferably -50° or more, and even more preferably -47° or more. Also, the transmission phase of the FSS is preferably 23° or less, more preferably 20° or less, and even more preferably 17° or less.

[0122] Furthermore, in the FSS-loaded member according to the present embodiment, when the FSS is provided in both a between the second layer and the third layer that the laminated member has and b between the (n-1)th layer and the (n-2)th layer of the laminated member, it is advisable to set it within the above preferable range.

[0123] Also, under the conditions that the incident angle of radio waves with a frequency of F is 55° or more, the relative permittivity of the first layer and the nth layer of the FSS-loaded member is 4 to 7, the thickness is 1 mm to 4 mm, the relative permittivity of the second layer and the (n-1)th layer is 1 to 7, the thickness is 0.1 mm to 1.6 mm, and the relative permittivity of the third layer and the (n-2)th layer is 1 to 7, the thickness is 0.1 mm to 4 mm, the transmission phase of such FSS is preferably -45° or more, more preferably -35° or more, and even more preferably -25° or more. Also, the transmission phase of the FSS under the same conditions is preferably 25° or less, more preferably 20° or less, and even more preferably 15° or less.

[0124] In the FSS-loaded member according to the present embodiment, when the FSS is provided on any two or more of the main surfaces of the dielectric layer constituting the laminated member, the transmission phase of at least one of the FSSs is preferably -45° to +25°. Since at least one of the transmission phases of the FSSs provided on two or more main surfaces is -45° to +25°, the reflected waves from each surface of the FSS-loaded member can be canceled out and the reflection can be reduced, thus improving the radio wave transmissivity.

[0125] Also, in the FSS-loaded member according to the present embodiment, when the FSS is provided on both of the two outermost surfaces that the laminated member has, the transmission phases of both of the FSSs are preferably -45° to +25°.

[0126] Among the FSSs provided on any two or more of the main surfaces of the dielectric layer constituting the laminated member, the transmission phase of at least one of them is preferably -43° or more, more preferably -40° or more, and even more preferably -37° or more.

[0127] Also, among the FSSs provided on two or more main surfaces, the transmission phase of at least one of them is preferably 24° or less, more preferably 22° or less, and even more preferably 20° or less.

[0128] Furthermore, in the FSS-loaded member according to the present embodiment, when the FSS is provided on both of the two outermost surfaces of the laminated member, it is also preferable to set it within the above preferable range.

[0129] Also, in the FSS-loaded member according to the present embodiment, when the FSS is provided on at least one of the positions between the third layer and the fourth layer of the laminated member and between the (n - 2)th layer and the (n - 3)th layer of the laminated member, it is preferable that the transmission phase of at least one of the FSSs is -55° to +25°. However, in this case, n is an integer of 6 or more.

[0130] The transmission phase of the FSS provided on at least one of the positions between the third layer and the fourth layer of the laminated member and between the (n - 2)th layer and the (n - 3)th layer of the laminated member is preferably -53° or more, more preferably -50° or more, and even more preferably -47° or more.

[0131] Also, the transmission phase of the FSS under the same conditions is preferably 23° or less, more preferably 20° or less, and even more preferably 17° or less. Furthermore, in the FSS-loaded member according to the present embodiment, when the FSS is provided on both of the positions a between the third layer and the fourth layer and b between the (n - 2)th layer and the (n - 3)th layer of the laminated member, it is also preferable to set it within the above preferable range.

[0132] In addition, in the FSS-loaded member according to the present embodiment, when the FSS is provided in at least one of the interfaces between the fourth layer and the fifth layer of the laminated member and between the (n - 3)-th layer and the (n - 4)-th layer of the laminated member, it is preferable that the transmission phase of at least one of the FSSs is in the range of -55° to +25°. However, in this case, n is an integer of 8 or more.

[0133] The transmission phase of the FSS provided in at least one of the interfaces between the fourth layer and the fifth layer of the laminated member and between the (n - 3)-th layer and the (n - 4)-th layer of the laminated member is preferably -53° or more, more preferably -50° or more, and even more preferably -47° or more.

[0134] Also, the transmission phase of the FSS under the same conditions is preferably 23° or less, more preferably 20° or less, and even more preferably 17° or less.

[0135] Furthermore, in the FSS-loaded member according to the present embodiment, when the FSS is provided in both the interface a between the fourth layer and the fifth layer of the laminated member and the interface b between the (n - 3)-th layer and the (n - 4)-th layer of the laminated member, it is also advisable to set it within the above preferable range.

[0136] The manufacturing method of the FSS-loaded member according to the present embodiment is not particularly limited. As a method of loading the FSS on the main surface of the dielectric layer, it may be formed directly on the main surface of the dielectric layer or indirectly.

[0137] For example, a conductor layer on a film such as resin, which has been pre-patterned to form the FSS, may be attached to the main surface of the dielectric layer together with the resin. Alternatively, the FSS may be directly loaded onto the main surface of the dielectric by plating or sputtering a desired metal or the like on the main surface of the dielectric layer. Thereafter, a dielectric layer such as a dielectric substrate or an intermediate may be laminated, and an FSS-loaded member may be obtained through a process of heating and pressurizing.

Examples

[0138] Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

[0139] [Calculation of FSS Transmission Phase] The FSS transmission phases in the examples and comparative examples were calculated using the finite element method software (High Frequency Structure Simulator (HFSS)) manufactured by Ansys, Inc. in the United States.

[0140] [Measurement of Sheet Resistance of FSS Conductive Part] The sheet resistances of the conductive parts of the FSS in the examples and comparative examples were measured using a non-contact eddy current method resistance measuring instrument 717 conductance monitor manufactured by DELCOM.

[0141] [Measurement of FSS Dimensions] The various dimensions of the FSS in the examples and comparative examples were measured using an optical microscope DSX-500 manufactured by Olympus.

[0142] [Radio Wave Transmittance Evaluation] For the FSS-loaded members or laminated members in the examples and comparative examples, the reflection characteristics (S11) and transmission characteristics (S21) when vertically polarized waves (TM waves) or horizontally polarized waves (TE waves) of 28 GHz or 78 GHz were incident at a predetermined incident angle were measured and calculated by actual measurement or simulation.

[0143] Specifically, for Examples 1, 2, 4, 10, 13, and 14, the reflection characteristics (S11) and transmission characteristics (S21) were measured by actual measurement as follows. First, the antennas were opposed to each other, and each obtained FSS-loaded member or laminated member was placed between them so that the incident angle was a predetermined angle. Then, for vertically polarized waves (TM waves) or horizontally polarized waves (TE waves) of a frequency of 28 GHz or 78 GHz, the reflection characteristics (S11) and transmission characteristics (S21) were measured when there was no radio wave transmission substrate at an opening of 100 mmΦ, with the case without the substrate being set to 0 [dB].

[0144] For one side, regarding Examples 3, 5 to 9, 11, 12, 15, 16, and 17, the reflection characteristics (S11) and transmission characteristics (S21) were measured by simulation as follows. That is, based on the relative permittivity ε r and the dielectric loss tangent tanδ (δ is the loss angle) values of each material used at 1 GHz, the reflection characteristics (S11) and transmission characteristics (S21) at 28 GHz and 78 GHz were calculated.

[0145] [Fabrication of FSS-loaded member] The FSS-loaded members or laminated members of Examples 1 to 17 were fabricated by the following procedure. Note that Examples 1 to 10 correspond to the examples, and Examples 11 to 17 correspond to the comparative examples. Note that Examples 3, 5, 7, and 8 are virtual samples.

[0146] <Example 1> On the entire one main surface of a first dielectric substrate 111 made of soda-lime glass with a square main surface of 300 mm × 300 mm and a thickness of 1.98 mm, after forming a 10-μm-thick Cu film by plating, a first frequency selective surface F11 in a circular loop slot shape shown in Fig. 3(C) was formed on the entire main surface by etching. Also, on the entire both main surfaces of a second dielectric substrate 113 made of soda-lime glass with a square main surface of 300 mm × 300 mm and a thickness of 1.98 mm, after forming a 10-μm-thick Cu film by plating, a second frequency selective surface F12 and a third frequency selective surface F13 in a circular loop slot shape shown in Fig. 3(C) were formed on the entire both main surfaces by etching. The dimensions of each part of the frequency selective surface shown in Fig. 3(C) were a periodic regular hexagonal pattern with p: 0.6 mm, t: 0.34 mm, and W: 0.23 mm for the first and second frequency selective surfaces F11 and F12. Also, for the third frequency selective surface F13, it was a periodic regular hexagonal pattern with p: 0.6 mm, t: 0.34 mm, and W: 0.20 mm.

[0147] Next, as shown in FIG. 7, the members were stacked in the order of the first dielectric substrate 111, the first frequency selective surface F11, the first intermediate body 112 made of a PVB film with a square main surface of 300 mm × 300 mm and a thickness of 0.76 mm, the second frequency selective surface F12, the second dielectric substrate 113, and the third frequency selective surface F13, and heated at 130 °C for 90 minutes under a pressure of 1 MPa and then gradually cooled to fabricate the frequency selective surface loaded member 110 of Example 1. In the frequency selective surface loaded member 110 of Example 1, the non-conductive portions of the first frequency selective surface F11 and the second frequency selective surface F12 are PVB, and the non-conductive portion of the third frequency selective surface F13 is air. The relative permittivity, dielectric loss tangent, thickness of the dielectric substrate and the intermediate body, various dimensions of the FSS, transmission phase, and total thickness are shown in Table 1. In Table 1, S1 and S2 are the areas of the non-conductive portion and the conductive portion of the FSS in plan view, respectively, and "S1 / S2" corresponds to "area of non-conductive portion / area of conductive portion". Note that also in Example 2 and later, the main surface is a square of 300 mm × 300 mm, and each FSS was formed over the entire surface of the predetermined main surface.

[0148] <Example 2> After forming a 10-μm-thick Cu film by plating on both main surfaces of the second dielectric substrate 213 made of soda-lime glass with a thickness of 1.98 mm, the first frequency selective surface F21 and the second frequency selective surface F22 having a circular loop slot shape shown in FIG. 3(C) were formed by etching. The dimensions of each part of the frequency selective surface shown in FIG. 3(C) were a periodic regular hexagonal pattern with p: 0.59 mm, t: 0.34 mm, and W: 0.2 mm for the first frequency selective surface F21. Also, for the second frequency selective surface F22, it was a periodic regular hexagonal pattern with p: 0.59 mm, t: 0.33 mm, and W: 0.2 mm.

[0149] Subsequently, as shown in FIG. 8, a first dielectric substrate 211 made of soda-lime glass with a thickness of 1.98 mm, a first intermediate body 212 (PVB film) made of a PVB film with a thickness of 0.76 mm, a first frequency selective surface F21, a second dielectric substrate 213, and a second frequency selective surface F22 are laminated in this order, and heated at 130° C. for 90 minutes under a pressure of 1 MPa and then slowly cooled to fabricate the frequency selective surface loading member 210 of Example 2. In the frequency selective surface loading member 210 of Example 2, the non-conductive portion of the first frequency selective surface F21 is PVB, and the non-conductive portion of the second frequency selective surface F22 is air. The relative permittivity, dielectric loss tangent, thickness of the dielectric substrate and the intermediate body, various dimensions of the FSS, transmission phase, and total thickness are shown in Table 1.

[0150] <Example 3> First, after forming a 10-μm-thick Cu film by plating on a 0.38-mm-thick PVB film, and then etching, a double lattice stripe-shaped first frequency selective surface F31 shown in FIG. 3(A) is formed on the PVB film. The dimensions of each part of the frequency selective surface F31 shown in FIG. 3(A) are: width G: 0.03 mm, L1: 0.2 mm, L2: 0.24 mm.

[0151] Subsequently, as shown in FIG. 9, a first dielectric substrate 311 made of soda-lime glass with a thickness of 1.98 mm, a first intermediate body 312 made of a 0.38-mm-thick PVB film, a first frequency selective surface F31, a second intermediate body 313 made of a 0.38-mm-thick PVB film, and a second dielectric substrate 314 made of soda-lime glass with a thickness of 1.98 mm are laminated in this order, and heated at 130° C. for 90 minutes under a pressure of 1 MPa and then slowly cooled to fabricate the frequency selective surface loading member 310 of Example 3. In the frequency selective surface loading member 310 of Example 3, the non-conductive portion of the first frequency selective surface F31 is PVB. The relative permittivity, dielectric loss tangent, thickness of the dielectric substrate and the intermediate body, various dimensions of the FSS, transmission phase, and total thickness are shown in Table 1.

[0152] <Example 4> First, on a PET film with a thickness of 0.1 mm, a multilayer film containing Ag and zinc oxide was formed by sputtering so that the sheet resistance became 2.0 Ω / sq. Then, using a laser with a wavelength of 532 nm, the first frequency selective surface F41 in the form of a double lattice stripe shown in Fig. 3(A) was formed. The dimensions of each part of the frequency selective surface F41 shown in Fig. 3(A) were width G: 0.038 mm, L1: 0.2 mm, and L2: 0.238 mm.

[0153] Subsequently, as shown in Fig. 10, a first dielectric substrate 411 made of soda-lime glass with a thickness of 2.04 mm, a first intermediate body 412 made of a PVB film with a thickness of 0.38 mm, the first frequency selective surface F41, a third intermediate body 413 made of a PET film with a thickness of 0.1 mm, a second intermediate body 414 made of a PVB film with a thickness of 0.38 mm, and a second dielectric substrate 415 made of soda-lime glass with a thickness of 2.01 mm were laminated in this order. By heating at 130 °C for 90 minutes under a pressure of 1 MPa and then gradually cooling, the frequency selective surface loading member 410 of Example 4 was fabricated. In the frequency selective surface loading member 410 of Example 4, the non-conductive part of the first frequency selective surface F41 is PVB. The relative permittivity, dielectric loss tangent, thickness of the dielectric substrate and the intermediate body, various dimensions of the FSS, transmission phase, and total thickness are shown in Table 1.

[0154] <Example 5> First, after forming a 10-μm-thick Cu film by plating on a PVB film with a thickness of 0.38 mm, the film was etched to form the first frequency selective surface F51 in the shape of a circular loop slot shown in Fig. 3(C) on the PVB film. The dimensions of each part of the frequency selective surface F51 shown in Fig. 3(C) are a periodic regular hexagonal pattern with p: 0.54 mm, t: 0.44 mm, and W: 0.055 mm in the first frequency selective surface F51.

[0155] Subsequently, as shown in FIG. 11, a first dielectric substrate 511 made of soda-lime glass with a thickness of 1.98 mm, a first intermediate body 512 made of a PVB film with a thickness of 0.38 mm, a first frequency selective surface F51, a second intermediate body 513 made of a PVB film with a thickness of 0.38 mm, and a second dielectric substrate 514 made of soda-lime glass with a thickness of 1.98 mm are laminated in this order. By heating at 130° C. for 90 minutes under a pressure of 1 MPa and then gradually cooling, the frequency selective surface loading member 510 of Example 5 is fabricated. In the frequency selective surface loading member 510 of Example 5, the non-conductive portion of the first frequency selective surface F51 is PVB. The relative permittivity, dielectric loss tangent, thickness of the dielectric substrate and the intermediate body, various dimensions of the FSS, transmission phase, and total thickness are shown in Table 1.

[0156] <Example 6> First, on a PET film with a thickness of 0.1 mm, a multilayer film containing Ag and zinc oxide was formed by sputtering so that the sheet resistance became 2.0 Ω / □. Then, using a laser with a wavelength of 532 nm, the first frequency selective surface F61 in the form of a double lattice stripe shown in FIG. 3(A) was formed. The dimensions of each part of the frequency selective surface F61 shown in FIG. 3(A) were width G: 0.04 mm, L1: 0.18 mm, and L2: 0.24 mm.

[0157] Subsequently, as shown in FIG. 12, a first dielectric substrate 611 made of soda-lime glass with a thickness of 1.80 mm, a first intermediate body 612 made of a PVB film with a thickness of 0.38 mm, the first frequency selective surface F61, a third intermediate body 613 made of a PET film with a thickness of 0.1 mm, a second intermediate body 614 made of a PVB film with a thickness of 0.38 mm, and a second dielectric substrate 615 are laminated in this order. By heating at 130° C. for 90 minutes under a pressure of 1 MPa and then gradually cooling, the frequency selective surface loading member 610 of Example 6 was fabricated. In the frequency selective surface loading member 610 of Example 6, the non-conductive portion of the first frequency selective surface F61 is PVB. The relative permittivity, dielectric loss tangent, thickness of the dielectric substrate and the intermediate body, various dimensions of the FSS, transmission phase, and total thickness are shown in Table 1.

[0158] <Example 7> First, after forming a 10-μm-thick Cu film by plating on a 0.38-mm-thick PVB film and then etching, a double-lattice stripe-shaped first frequency selective surface F71 shown in Fig. 3(A) is formed on the PVB film. The dimensions of each part of the first frequency selective surface F71 shown in Fig. 3(A) are: width G: 0.06 mm, L1: 0.25 mm, L2: 0.30 mm.

[0159] Subsequently, as shown in Fig. 13, each member is laminated in the order of a first dielectric substrate 711 made of soda-lime glass with a thickness of 2.80 mm, a first intermediate body 712 made of a 0.38-mm-thick PVB film, the first frequency selective surface F71, a second intermediate body 713 made of a 0.38-mm-thick PVB film, and a second dielectric substrate 714 made of soda-lime glass with a thickness of 2.80 mm, and then heated at 130 °C for 90 minutes under a pressure of 1 MPa and gradually cooled to fabricate the frequency selective surface loading member 710 of Example 7. In the frequency selective surface loading member 710 of Example 7, the non-conductive part of the first frequency selective surface F71 is PVB. The relative permittivity, dielectric loss tangent, thickness of the dielectric substrate and the intermediate body, various dimensions of the FSS, transmission phase, and total thickness are shown in Table 1.

[0160] <Example 8> First, after forming a 10-μm-thick Cu film by plating on a 0.38-mm-thick PVB film and then etching, a double-lattice stripe-shaped first frequency selective surface F81 shown in Fig. 3(A) is formed on the PVB film. The dimensions of each part of the first frequency selective surface F81 shown in Fig. 3(A) are: width G: 0.03 mm, L1: 0.16 mm, L2: 0.26 mm.

[0161] Subsequently, as shown in FIG. 14, a first dielectric substrate 811 made of borosilicate glass with a thickness of 2.00 mm, a first intermediate body 812 made of a PVB film with a thickness of 0.38 mm, a first frequency selective surface F81, a second intermediate body 813 made of a PVB film with a thickness of 0.38 mm, and a second dielectric substrate 814 made of borosilicate glass with a thickness of 2.00 mm are laminated in this order, and heated at 130° C. for 90 minutes under a pressure of 1 MPa and then gradually cooled to fabricate the frequency selective surface loading member 810 of Example 8. In the frequency selective surface loading member 810 of Example 8, the non-conductive portion of the first frequency selective surface F81 is PVB. The relative permittivity, dielectric loss tangent, thickness of the dielectric substrate and the intermediate body, various dimensions of the FSS, transmission phase, and total thickness are shown in Table 1.

[0162] <Example 9> On one main surface of a second dielectric substrate 913 made of non-alkali glass with a thickness of 1.98 mm, a multilayer film containing Ag and zinc oxide was formed by sputtering so that the sheet resistance became 1.0 Ω / sq, and then, using a laser with a wavelength of 532 nm, the first frequency selective surface F91 having a circular loop slot shape shown in FIG. 3(C) was formed. The dimensions of each part of the first frequency selective surface F91 shown in FIG. 3(C) were a periodic regular hexagonal pattern with p: 0.62 mm, t: 0.42 mm, and W: 0.2 mm.

[0163] Subsequently, as shown in FIG. 15, a first dielectric substrate 911 made of non-alkali glass with a thickness of 1.98 mm, a first intermediate body 912 made of a PVB film with a thickness of 0.76 mm, a second dielectric substrate 913 made of non-alkali glass with a thickness of 1.98 mm, and the first frequency selective surface F91 are laminated in this order, and heated at 130° C. for 90 minutes under a pressure of 1 MPa and then gradually cooled to fabricate the frequency selective surface loading member 910 of Example 9. In the frequency selective surface loading member 910 of Example 9, the non-conductive portion of the first frequency selective surface F91 is air. The relative permittivity, dielectric loss tangent, thickness of the dielectric substrate and the intermediate body, various dimensions of the FSS, transmission phase, and total thickness are shown in Table 1.

[0164] <Example 10> On one main surface of a second dielectric substrate 1013 made of soda-lime glass with a thickness of 2.00 mm, a multilayer film containing Ag and zinc oxide was formed by sputtering so that the sheet resistance became 1.8 Ω / □. Then, using a laser with a wavelength of 532 nm, a double lattice stripe-shaped first frequency selective surface F101 shown in FIG. 3(A) was formed. The dimensions of each part of the first frequency selective surface F101 shown in FIG. 3(A) were set as width G: 0.03 mm, L1: 0.3 mm, and L2: 0.32 mm.

[0165] Subsequently, as shown in FIG. 16, a spacer with a thickness of 6.00 mm was provided so as to surround the periphery of a first dielectric substrate 1011 made of soda-lime glass with a thickness of 2.00 mm and the second dielectric substrate 1013. Each member was laminated and fixed in the order of a first intermediate body 1012 composed of an air layer with a thickness of 6.00 mm, the first frequency selective surface F101, and the second dielectric substrate 1013 made of soda-lime glass with a thickness of 2.00 mm, and a frequency selective surface loading member 1010 of Example 10 was fabricated. In the frequency selective surface loading member 1010 of Example 10, the non-conductive part of the first frequency selective surface F101 is air. The relative permittivity, dielectric loss tangent, thickness, various dimensions of the FSS, transmission phase, and total thickness of the dielectric substrate and the intermediate body are shown in Table 1.

[0166] <Examples 11, 12, 13, 15, 16, 17> A PVB film with a thickness of 0.76 mm was inserted as a first intermediate body between a first dielectric substrate made of soda-lime glass with a thickness of 1.98 mm and a second dielectric substrate made of soda-lime glass with a thickness of 1.98 mm, heated at 130 °C for 90 minutes under a pressure of 1 MPa, and then slowly cooled to fabricate a laminated member of Example 11. The relative permittivity, dielectric loss tangent, thickness, and total thickness of the dielectric substrate and the intermediate body are shown in Table 1.

[0167] Also, for Examples 12, 13, 15, 16, and 17, each laminated member was fabricated in the same manner as in Example 11, except that soda-lime glass or alkali-free glass or borosilicate glass was used for the first dielectric substrate and the second dielectric substrate, and at least one of the relative permittivity and thickness of the glass was changed, as shown in Table 1.

[0168] <Example 14> A 6.00 mm thick spacer was provided between a first dielectric substrate made of 2.00 mm thick soda lime glass and a second dielectric substrate made of 2.00 mm thick soda lime glass so as to surround the periphery of these dielectric substrates, and a first intermediate body made of a 6 mm thick air layer was provided to produce the laminated member of Example 14. The relative dielectric constant, dielectric loss tangent, thickness, and total thickness of the dielectric substrates and intermediate body are shown in Table 1.

[0169] [Table 1]

[0170] Table 2 shows the results of evaluation of the radio wave transmittance of the frequency selective surface loading members or laminated members of Examples 1 to 17.

[0171] [Table 2]

[0172] Comparing Example 1 and Example 11, the FSS-loaded member of Example 1, in which an FSS was placed at a specified position, had a lower reflection characteristic S11 and a higher transmission characteristic S21 at 78 GHz than Example 11, in which no FSS was provided, and thus had improved radio wave transmission.

[0173] Comparing Example 2 and Example 11, the FSS-loaded member of Example 2, in which an FSS was placed at a specified position, had a lower reflection characteristic S11 and a higher transmission characteristic S21 at 78 GHz than Example 11, in which no FSS was provided, resulting in improved radio wave transmission.

[0174] Comparing Example 3 and Example 11, the FSS-loaded member of Example 3, in which an FSS was placed at a specified position, had a lower reflection characteristic S11 and a higher transmission characteristic S21 at 78 GHz than Example 11, in which no FSS was provided, resulting in improved radio wave transmittance.

[0175] Comparing Example 4 with Example 13, the FSS-loaded member of Example 4 with the FSS disposed at a predetermined position had a lower reflection characteristic S11 and a higher transmission characteristic S21 at 28 GHz, and improved radio wave transmissivity, as compared with Example 13 without the FSS. Further, although the reflection characteristic S11 of the FSS-loaded member of Example 4 at 78 GHz was higher than that of Example 13, the transmission characteristic S21 was high.

[0176] Comparing Example 5 with Example 11, the FSS-loaded member of Example 5 with the FSS disposed at a predetermined position had a lower reflection characteristic S11 and a higher transmission characteristic S21 at 78 GHz, and improved radio wave transmissivity, as compared with Example 11 without the FSS.

[0177] Comparing Example 6 with Example 16, the FSS-loaded member of Example 6 with the FSS disposed at a predetermined position had a lower reflection characteristic S11 and a higher transmission characteristic S21 at 78 GHz, and improved radio wave transmissivity, as compared with Example 16 without the FSS.

[0178] Comparing Example 7 with Example 17, the FSS-loaded member of Example 7 with the FSS disposed at a predetermined position had a lower reflection characteristic S11 and a higher transmission characteristic S21 at 78 GHz, and improved radio wave transmissivity, as compared with Example 17 without the FSS.

[0179] Comparing Example 8 with Example 15, the FSS-loaded member of Example 8 with the FSS disposed at a predetermined position had a lower reflection characteristic S11 and a higher transmission characteristic S21 at 78 GHz, and improved radio wave transmissivity, as compared with Example 15 without the FSS.

[0180] Comparing Example 9 with Example 12, the FSS-loaded member of Example 9 with the FSS disposed at a predetermined position had a lower reflection characteristic S11 and a higher transmission characteristic S21 at 78 GHz, and improved radio wave transmissivity, as compared with Example 12 without the FSS.

[0181] Comparing Example 10 with Example 14, the FSS-loaded member of Example 10 with the FSS disposed at a predetermined position had a lower reflection characteristic S11 and a higher transmission characteristic S21 at 28 GHz, and improved radio wave transmissivity, as compared with Example 14 without the FSS.

[0182] Although the various embodiments have been described above with reference to the drawings, it goes without saying that the present invention is not limited to such examples. It is obvious that those skilled in the art can conceive of various modifications or corrections within the scope described in the claims, and it is naturally understood that they also belong to the technical scope of the present invention. Also, within the scope not departing from the gist of the invention, the respective components in the above embodiments may be arbitrarily combined.

[0183] This application is based on a Japanese patent application filed on August 3, 2020 (Japanese Patent Application No. 2020-131975), the content of which is incorporated herein by reference.

Description of Reference Numerals

[0184] 10, 40, 50, 60, 110, 210, 310, 410, 510, 610, 710, 810, 910, 1010 Frequency Selective Surface Loading Members 111, 113, 211, 213, 311, 314, 411, 415, 511, 514, 611, 615, 711, 714, 811, 814, 911, 913, 1011, 1013 Dielectric Substrates 112, 212, 312, 313, 412, 413, 414, 512, 513, 612, 613, 614, 712, 713, 812, 813, 912, 1012 Intermediates 30a, 30b, 30c, F11, F12, F13, F21, F22, F31, F41, F51, F61, F71, F81, F91, F101 Frequency Selective Surfaces 31a, 31b, 31c Conductive Parts 32a, 32b, 32c Non-Conductive Parts

Claims

1. A laminated member having a total of n dielectric layers laminated in order from the first layer to the nth layer (where n is an integer of 3 or more), A frequency selective surface that transmits radio waves of a predetermined frequency F is provided on at least one of the main surfaces of the dielectric layers constituting the laminated member, The frequency selective surface has a conductive portion and a non-conductive portion, The total thickness is 1.5 mm or more, The frequency selective surface is provided on at least one of the two outermost surfaces of the laminated member, A frequency selective surface loaded member in which the transmission phase of the frequency selective surface provided on at least one of the two outermost surfaces is -50° to +50°.

2. The frequency selective surface is provided on at least one of the space between the first layer and the second layer of the laminated member and the space between the nth layer and the n - 1th layer of the laminated member, The frequency selective surface loaded member according to claim 1, wherein the transmission phase of the frequency selective surface provided on at least one of the space between the first layer and the second layer of the laminated member and the space between the nth layer and the n - 1th layer of the laminated member is -30° to +30°.

3. It has a laminated member having a total of n dielectric layers laminated in order from the first layer to the nth layer (where n is an integer of 4 or more), A frequency selective surface that transmits radio waves of a predetermined frequency F is provided on at least one of the main surfaces of the dielectric layers constituting the laminated member, The frequency selective surface has a conductive portion and a non-conductive portion, The total thickness is 1.5 mm or more, The frequency selective surface is provided on at least one of the space between the second layer and the third layer of the laminated member and the space between the n - 1th layer and the n - 2th layer of the laminated member, A frequency selective surface loaded member in which the transmission phase of the frequency selective surface provided on at least one of the space between the second layer and the third layer of the laminated member and the space between the n - 1th layer and the n - 2th layer of the laminated member is -55° to +25°.

4. The frequency selective surface is provided on any two or more of the main surfaces of the dielectric layers constituting the laminated member, The frequency selective surface loaded member according to any one of claims 1 to 3, wherein the transmission phase of the frequency selective surface provided on the two or more surfaces is -45° to +25°.

5. The frequency selective surface loaded member according to any one of claims 1 to 4, wherein the relative permittivity of the dielectric layer of the laminated member is 1 or more and 7.2 or less.

6. The frequency selective surface loading member according to claim 5, wherein the relative permittivity of the dielectric layers of the first layer and the nth layer of the laminated member is 2.3 or more and 7.2 or less.

7. The frequency selective surface loading member according to any one of claims 1 to 6, wherein in a plan view, non-conductive portions are formed in a double lattice stripe shape, and one unit of a quadrangle is regularly arranged two-dimensionally without gaps.

8. The frequency selective surface loading member according to any one of claims 1 to 6, wherein in a plan view, conductive portions are formed in a double lattice stripe shape, and one unit of a quadrangle is regularly arranged two-dimensionally without gaps.

9. The frequency selective surface loading member according to claim 7 or 8, wherein in a plan view, the shortest distance L1 between adjacent double lattices and the length L2 formed within the double lattice are 0.05 mm to 5 mm, and the width G of the double lattice stripe is 0.03 mm to 1 mm.

10. The frequency selective surface loading member according to any one of claims 1 to 6, wherein in a plan view, a plurality of ring-shaped non-conductive portions are formed.

11. The frequency selective surface, in a plan view, a regular triangular arrangement without gaps is formed such that a regular hexagonal portion composed of the conductive portion and the ring-shaped non-conductive portion shares each side of the regular hexagonal portion, the center of the ring-shaped non-conductive portion is the same as the center of the regular hexagonal portion, and the ring-shaped non-conductive portion is formed inside the regular hexagonal portion, The frequency selective surface loading member according to claim 10, wherein the distances between the centers of adjacent ring-shaped non-conductive portions are all equal.

12. The frequency selective surface loading member according to any one of claims 1 to 11, wherein the sheet resistance of the conductive portion of the frequency selective surface is 50 Ω / □ or less.

13. The frequency selective surface loading member according to any one of claims 1 to 12, wherein the conductive portion of the frequency selective surface contains at least one selected from the group consisting of Ag, ITO, tin oxide doped with at least one of fluorine and antimony, and Cu.

14. The frequency selective surface loading member according to any one of claims 1 to 13, wherein the non-conductive portion of the frequency selective surface contains at least one selected from PVB, EVA, and air.

15. The radio wave of the frequency F is included in the range of 1 GHz to 100 GHz, and is the frequency selective surface loading member according to any one of claims 1 to 14.

16. The radio wave of the frequency F is a vertically polarized wave or a horizontally polarized wave incident at an incident angle of 0° to 80°, and is the frequency selective surface loading member according to any one of claims 1 to 15.

17. The radio wave of the frequency F is a vertically polarized wave or a horizontally polarized wave incident at an incident angle of 60° to 70°, and is the frequency selective surface loading member according to claim 16.

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