Antenna device and wireless communication device

Abstract

Provided are: an antenna device capable of protecting a resin member of an antenna from ultraviolet rays; and a wireless communication device.　This antenna device comprises an antenna that is disposed so as to face a main surface of a window glass, and a matching layer that is provided between the window glass and the antenna. In the matching layer, the transmittance of light having a wavelength of 380 nm is 5% or less, the dielectric constant ε at 4.5 GHz is 2.0 to 7.0, inclusive, and the dielectric loss tangent tanδ is 1.0×10-5 to 0.1, inclusive.

Description

Antenna device and wireless communication device

[0001] The present disclosure relates to an antenna device and a wireless communication device.

[0002] 2. Description of the Related Art Conventionally, there have been repeaters that are installed on windows and include a mounting portion that is fixed to the window glass and an array antenna that is held by the mounting portion (see, for example, Patent Document 1).

[0003] US Patent Application Publication No. 2020 / 144692

[0004] The antenna has a resin substrate, a resin cover, or other resin components that deteriorate due to ultraviolet rays. However, conventional repeater array antennas (antennas) do not protect the resin components of the antenna from ultraviolet rays.

[0005] Therefore, an object of the present invention is to provide an antenna device and a wireless communication device that can protect the resin member of the antenna from ultraviolet rays.

[0006] An antenna device according to an embodiment of the present disclosure includes an antenna disposed opposite a main surface of a window glass, and a matching layer provided between the window glass and the antenna, wherein the matching layer has a transmittance of 5% or less for light having a wavelength of 380 nm, a relative dielectric constant ε at 4.5 GHz of 2.0 or more and 7.0 or less, and a dielectric loss tangent tanδ of 1.0×10 －５ or more and 0.1 or less.

[0007] It is possible to provide an antenna device and a wireless communication device that can protect the resin member of the antenna from ultraviolet rays.

[0008] FIG. 1 is a diagram showing, in plan view, an example of a building in which a window is installed in which a wireless communication device including the antenna device of an embodiment is installed; FIG. 2 is a diagram showing an example of the configuration of the wireless communication device and the window of an embodiment; FIG. 3 is a diagram explaining details of the configuration of the antenna of the antenna device of an embodiment and an example of the interval t; FIG. 4 is a diagram showing an example of the circuit configuration of a wireless device; FIG. 5 is a diagram explaining an example of the relationship between sunlight that passes through window glass installed in a window of a building and enters the interior side and the solar altitude; FIG. 6 is a diagram explaining an example of how sunlight is incident on a comparative antenna device; FIG. 7 is a diagram showing an example of how sunlight is incident on the antenna device of an embodiment; FIG. 8 is a diagram explaining an example of calculation of the position of the upper end of the matching layer of the antenna device of an embodiment; FIG. 9 is a diagram showing an example of the cross-sectional configuration of a matching layer according to a modified example of an embodiment.

[0009] Hereinafter, embodiments to which the antenna device and wireless communication device of the present disclosure are applied will be described. In the following, the same elements will be denoted by the same reference numerals, and duplicated descriptions may be omitted.

[0010] In the following description, the XYZ coordinate system is defined. The direction parallel to the X axis (X direction), the direction parallel to the Y axis (Y direction), and the direction parallel to the Z axis (Z direction) are perpendicular to one another. The XYZ coordinate system is an example of a Cartesian coordinate system. In the following description, the length, width, thickness, etc. of each part may be exaggerated to make the configuration easier to understand. Furthermore, terms such as parallel, right angle, orthogonal, horizontal, vertical, up and down, etc., are intended to allow for deviations to the extent that they do not impair the effects of the embodiments.

[0011] In the following description, "radio waves" refers to a type of electromagnetic wave, and generally, electromagnetic waves of 3 THz or less are called radio waves. Hereinafter, electromagnetic waves of 3 THz or less emitted from an outdoor base station or relay station will be referred to as "radio waves," and electromagnetic waves in general will be referred to as "electromagnetic waves."

[0012] The radio waves relayed by the wireless communication device including the antenna device of the embodiment are preferably radio waves in a frequency band of 600 MHz to 40 GHz, including the Sub-6 frequency band and millimeter wave bands such as those of fifth-generation mobile communication systems (5G), and more preferably radio waves in a frequency band of 700 MHz to 30 GHz.The wireless communication device including the antenna device of the embodiment functions as a repeater that relays radio waves arriving from an outdoor base station or the like indoors.The repeater may also have the function of receiving radio waves arriving from an outdoor base station or the like, converting the radio waves into radio waves of a communication standard different from the communication standard of the radio waves arriving from the base station or the like, and relaying the converted radio waves indoors.

[0013] Furthermore, radio waves relayed by the wireless communication device including the antenna device of the embodiment may be Long Term Evolution (LTE), LTE-Advanced (LTE-A), Ultra Mobile Broadband (UMB), or Citizens Broadband Radio Service (CBRS). Furthermore, radio waves relayed by the wireless communication device of the embodiment may be IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, Ultra Wideband (UWB), Bluetooth (registered trademark), Low Power Wide Area (LPWA), or the like.

[0014] 1 is a plan view of an example of a building 1 in which a window 10 is installed with a wireless communication device 200 including an antenna device according to an embodiment. In addition to the building 1 and the wireless communication device 200, Fig. 1 also shows a base station BS, a PC (Personal Computer) 50, and a smartphone 60.

[0015] The building 1 may be a detached house, a building, an apartment building, or a commercial facility such as a shopping mall or a department store, an airport, a factory, a power facility, a government building, a train station (station building), or a bus stop building. The window 10 is used in these buildings 1. The window 10 includes a window glass and a window frame (the window frame on the building 1 side). The wireless communication device 200 functions as a repeater.

[0016] The antenna of the wireless communication device 200 is preferably provided on the window glass of the window 10, and the portions other than the antenna may be provided on the window 10 or on the wall 1A or bay window frame near the window 10. The antenna of the wireless communication device 200 is the antenna of the antenna device of the embodiment included in the wireless communication device 200. Furthermore, the portions other than the antenna of the wireless communication device 200 do not have to be fixed to the wall 1A, ceiling, or bay window frame near the window 10, and may simply be placed on a flat surface, for example.

[0017] Radio waves in the Sub-6 frequency band and millimeter wave bands such as those of the fifth generation mobile communication system (5G) emitted from an outdoor base station BS enter the building 1 only through the glass of the window 10, but because they have a high degree of directivity, they only reach a part of the building, making it easy for dead zones to occur. The glass of the window 10 is the entrance point for radio waves into the building 1.

[0018] Because it is difficult to create a good communication environment indoors for radio waves in the Sub-6 frequency band or millimeter wave bands such as those of the fifth-generation mobile communication system (5G), the antenna of the wireless communication device 200 is provided on the window 10 to improve the reception environment and expand the communication area. Here, providing the wireless communication device 200 on the window 10 means that, as described above, the antenna is provided on the window glass, and parts other than the antenna may be provided on the window 10 or a wall 1A or bay window frame near the window 10. When relaying radio waves, the wireless communication device 200 receives radio waves with the antenna through the window glass of the window 10, amplifies the radio waves, and radiates them indoors. In FIG. 1 , the wireless communication device 200 is provided on the indoor side of the window 10, but it may also be provided on the outdoor side of the window 10.

[0019] When relaying radio waves arriving from outside the window 10, the wireless communication device 200 amplifies the received radio waves and radiates the amplified radio waves indoors at a predetermined radiation angle using an array antenna or the like. The amplified radio waves are radiated over a wide area indoors, making it easy for indoor terminals to receive the radio waves.

[0020] For example, when relaying radio waves, the wireless communication device 200 may receive, amplify, and radiate radio waves of multiple frequencies. By relaying radio waves of multiple frequencies, the amplified radio waves can be radiated over a wider area indoors and communication performance can be improved.

[0021] Furthermore, radio waves in the Sub-6 frequency band or millimeter wave band such as that of the fifth generation mobile communication system (5G) are attenuated when they pass through the window glass of window 10. In order to suppress radio wave attenuation (loss), it is preferable to use a matching layer. By using a matching layer, when wireless communication device 200 relays radio waves, it is possible to reduce loss by adjusting the electrical length of the radio waves before or after they pass through the window glass to match the impedance.

[0022] 2 is a diagram showing an example of the configuration of the wireless communication device 200 and the window 10. The wireless communication device 200 includes an antenna device 100 and is attached to the window 10. The window 10 includes a window glass 11 and a window frame 12.

[0023] Here, the configuration of the window 10, the configuration of the wireless communication device 200 and its attachment structure to the window 10, and the configuration of the antenna device 100 will be described in that order.

[0024] <Configuration of window 10> In the following, as an example, a configuration in which the window 10 is a fixed window will be described, but the window 10 may also be a sliding window that can be opened and closed freely, a casement window, etc. Furthermore, the window glass 11 held by the window frame may be either one pane or multiple panes.

[0025] The window glass 11 has an indoor main surface 11A and an outdoor main surface. The window glass 11 may be made of commonly available glass, such as soda-lime glass, alkali-free glass, Pyrex (registered trademark) glass, or quartz glass. The window glass 11 is not limited to a glass plate, and may also be made of a resin surface material such as polycarbonate or acrylic.

[0026] The window frame 12 is a frame-shaped member that surrounds the edge of the window glass 11 and is made of metal such as aluminum, or resin.

[0027] The window glass 11 and window frame 12 of the window 10 are provided on a wall 1A perpendicular to a horizontal plane. The indoor main surface 11A of the window glass 11 is parallel to the indoor surface 12A of the window frame 12, and the thickness (thickness in the Z direction) of the window glass 11 and the window frame 12 is constant.

[0028] <Configuration of wireless communication device 200 and attachment structure to window 10> Wireless communication device 200 includes antenna device 100, waveguide 170, wireless device 210, and bracket 220. Waveguide 170 is an example of a transmission path. Bracket 220 is an example of a fixture. Wireless communication device 200 is installed, for example, on the indoor side of building 1 (see FIG. 1 ).

[0029] Note that, as an example, a configuration in which wireless communication device 200 includes waveguide 170 will be described here, but the following transmission path may be used instead of waveguide 170. For example, a coaxial cable, or an FPC (Flexible Printed Circuit) transmission path having a transmission line such as a microstrip line (MSL) or a coplanar waveguide (CPW) formed on a flexible substrate made of polyimide or the like may be used. The FPC transmission path is an example of a transmission path having a flexible substrate and a transmission line such as an MSL or a CPW formed on the flexible substrate.

[0030] Here, the XYZ coordinate system is defined based on the indoor surface 12A of the window frame 12 to which the wireless device 210 is attached. The X axis is an example of the first axis, the Y axis is an example of the second axis, and the Z axis is an example of the third axis. The X direction is an example of the first axis direction, the Y direction is an example of the second axis direction, and the Z direction is an example of the third axis direction.

[0031] The indoor-side surface 12A of the window frame 12 is a plane including the X and Y directions. The surface 12A is parallel to the XY plane. The Z direction is a direction perpendicular to the surface 12A and corresponds to the direction of the normal to the surface 12A. The +Z direction side of the surface 12A is the indoor side. The Y direction in this XYZ coordinate system is a direction connecting the wireless device 210 and the window glass 11. The X direction is a direction in which the upper part of the rectangular-annular window frame 12 extends in the XY plane (plan view). Note that, while the window glass 11 is rectangular in plan view and the window frame 12 is frame-shaped (rectangular-annular) in plan view, the window glass 11 is not limited to a rectangular shape in plan view. For example, the window glass 11 may have a shape with a curved outer edge, such as a circle or an ellipse. In this case, the window frame 12 may be a frame-shaped member that surrounds the window glass 11 having such a curved outer edge.

[0032] Furthermore, viewing the window glass 11 in a plan view (XY plane view) means viewing the window glass 11 from a direction directly opposite the main surface, and in the case of the antenna device 100 and the wireless communication device 200, viewing the window glass 11 in a direction directly opposite the main surface when attached to the window glass 11 and window frame 12 is also referred to as a plan view.

[0033] 2 are horizontal directions, and the XZ plane is parallel to the horizontal plane. The Y direction is the vertical direction, the +Y direction is the vertically upward direction, and the -Y direction is the vertically downward direction. In the following description, the +Y direction side is the upper side, and the -Y direction side is the lower side.

[0034] As an example, two waveguides 170 are provided between the antenna device 100 and the wireless device 210. The two waveguides 170 are arranged parallel to each other with a gap in the X direction and have the same length. The relative positions of the antenna device 100 and the wireless device 210 in the X direction are determined by the two waveguides 170. As an example, the antenna device 100 may be configured to guide two types of radio waves (high-frequency signals), one horizontally polarized and one vertically polarized.

[0035] The waveguide 170 has an end 151 connected to the antenna 110 of the antenna device 100 and an end (not shown) connected to the wireless device 210, and guides radio waves received by the antenna device 100. Here, as an example, a configuration in which the wireless communication device 200 includes two waveguides 170 will be described, but the number of waveguides 170 may be one, or three or more. Furthermore, four waveguides 170 may be provided corresponding to four antennas 110. Note that even when there is one waveguide 170, the relative positions of the antenna device 100 and the wireless device 210 do not need to be adjusted in the X direction, and therefore the relative positions of the antenna device 100 and the wireless device 210 in the X direction are determined by the single waveguide 170.

[0036] As described above, a coaxial cable or an FPC transmission line can be used instead of the waveguide 170. In this case, an RF component such as an amplifier may be mounted on the transparent antenna device 100. The relative positions of the antenna device 100 and the wireless device 210 in the X direction are determined by the FPC transmission line.

[0037] Waveguide 170 is, as an example, a bendable waveguide that extends from antenna 110 of antenna device 100 in the +Z direction, is bent in the +Y direction, and extends to the lower end of wireless device 210. Waveguide 170 is almost inflexible, but can be bent at any position between end 151 and the end connected to wireless device 210. As such a bendable waveguide 170, for example, a flexible waveguide can be used.

[0038] Wireless device 210 is fixed by screws 240 to two brackets 220 attached to indoor surface 12A of window frame 12. That is, wireless device 210 is attached to indoor surface 12A of window frame 12 by two screws 240 and two brackets 220. Note that instead of screws 240, a protrusion that is formed integrally with housing 231 and protrudes in the X direction may be provided.

[0039] The wireless device 210 has a wireless communication unit in addition to the array antenna 210A and the housing 231. The array antenna 210A and the wireless communication unit are arranged inside the housing 231. The wireless device 210 may also have a heat dissipation unit that dissipates heat from the wireless communication unit. The housing 231 is, for example, a rectangular parallelepiped resin case. The housing 231 is fixed to the bracket 220 with screws 240. The array antenna 210A is provided on the +Z direction side inside the housing 231. The wireless communication unit is omitted here. The wireless communication unit will be described later using FIG. 4.

[0040] The wireless communication unit is connected to the end of the waveguide 170 (the end connected to the wireless device 210), and performs processes such as amplifying the radio waves received from the antenna device 100 via the waveguide 170 and outputting the amplified waves to the array antenna 210A, and controlling the radiation direction in which the array antenna 210A radiates the radio waves. For this reason, the wireless communication unit includes an amplifier, a microcomputer, etc.

[0041] As an example, the brackets 220 are fixed to the indoor surface 12A of the window frame 12 via double-sided tape, as shown in FIG. 2 . The brackets 220 are made of resin, metal, or the like. One bracket 220 is provided on each of the +X direction side and the −X direction side of the housing 231 of the wireless device 210, and one bracket 220 is disposed so as to sandwich the ±X direction ends of the wireless device 210. The brackets 220 may also be fixed to the window frame 12 with screws or the like. Fixing with screws is particularly effective when the surface 12A of the window frame 12 is not flat or when the material makes it difficult to fix with double-sided tape.

[0042] When the wireless communication device 200 is attached to the window 10, it is better to place it on the indoor side of the building 1 (see FIG. 1 ) to protect it from wind, rain, dust, etc., and to ensure stable operation over a long period of time. For this reason, the wireless communication device 200 is placed indoors.

[0043] Furthermore, when the wireless communication device 200 is attached to the window 10, it is preferable that the antenna device 100 be provided in a portion that overlaps the window glass 11 in order to efficiently receive radio waves that pass through the window glass 11. For this reason, in the embodiment, as an example, each portion of the antenna device 100 is made transparent, and the antenna device 100 is attached to the window glass 11, thereby realizing efficient reception of radio waves propagating from outdoors and suppressing obstruction of the view of the window glass 11.

[0044] On the other hand, the amplifier, microcomputer, etc. of the wireless device 210 generate heat due to amplification processing and control of the array antenna 210A, so if the wireless device 210 is attached to the window glass 11, the heat may damage or break the window glass 11. Also, it is difficult to make the wireless device 210 itself optically transparent. For these reasons, it is more convenient to attach the wireless device 210 to the window frame 12. In particular, if the window frame 12 is made of metal, it is possible to dissipate the heat generated by the wireless device 210 via the window frame 12.

[0045] For the reasons described above, in the embodiment, the antenna device 100 is attached to the window glass 11, and the wireless device 210 is attached to the window frame 12. Here, as an example, a configuration will be described in which the antenna device 100 and the wireless device 210 are attached to the upper side (+Y direction side) of the window glass 11 and the window frame 12. However, the same applies to a configuration in which the antenna device 100 and the wireless device 210 are attached to the lower side (-Y direction side) or side (+X direction side or -X direction side) of the window glass 11 and the window frame 12.

[0046] Although the embodiment in which wireless device 210 is provided on window frame 12 will be described here, wireless device 210 may also be provided on a structural part such as a wall located near windowpane 11. Wireless device 210 may also be provided on a desk near the window, the frame of a bay window, or the like.

[0047] <Configuration of Antenna Device 100> The antenna device 100 includes an antenna 110, a matching layer 120, and a holder 160. The holder 160 is an example of a holding portion. Although there may be only one antenna 110, as an example, a configuration including multiple antennas 110 will be described here as a configuration capable of MIMO (Multi-Input Multi-Output) communication. In FIG. 2, there are four antennas 110, as an example.

[0048] The holder 160 that holds the antenna 110 and the matching layer 120 is, for example, adhered to the indoor main surface 11A of the window glass 11 by double-sided tape. For example, with this configuration, the antenna device 100 is disposed on the indoor side of the window glass 11. In addition to the antenna 110 and the matching layer 120, the holder 160 also holds a base material, an adhesive layer, etc. (not shown), but these are omitted in FIG. 2 .

[0049] The antenna device 100 may also be provided on the outdoor side of the window glass 11. In this case, the holder 160 may be fixed to the outdoor main surface of the window glass 11 with double-sided tape or the like, and the matching layer 120 and the antenna 110 may be positioned from the outdoor side to the outdoor side of the window glass 11.

[0050] <Antenna 110> The antenna 110 is disposed on the indoor side of the window glass 11, and as an example, is disposed at a distance from the window glass 11. The antenna 110 is held together with the matching layer 120 by a holder 160, and is disposed at a distance from the window glass 11. Here, an outline of the antenna 110 will first be described using Figure 2.

[0051] The four antennas 110 have the same configuration and are spaced the same distance from the main surface 11A of the window glass 11. Each antenna 110 can be realized, for example, by a phased array antenna. A phased array antenna has a plurality of antenna elements.

[0052] The four antennas 110 are connected to the wireless device 210 via the waveguide 170. The antennas 110 and the wireless device 210 may be connected by a transmission path capable of transmitting radio waves, and as an example, are connected by the waveguide 170.

[0053] The four antennas 110 receive radio waves that have passed through the window glass 11 and the matching layer 120. The radio waves radiated from the four antennas 110 are transmitted to the outside of the building 1 after passing through the matching layer 120 and the window glass 11.

[0054] The antenna 110 receives radio waves emitted from an outdoor base station BS or the like. As an example, the antenna 110 is formed on the surface of the substrate 111 on the -Z direction side. The substrate 111 is preferably transparent. Here, "transparent" means transparent to visible light. "Transparent" to visible light means that the luminous transmittance is at least 40% or more, preferably 60% or more, more preferably 70% or more, and even more preferably 80% or more.

[0055] The antenna 110 is preferably placed close to the window glass 11. This is because it is easier to receive radio waves when the antenna is closer to the window glass 11. As an example, the distance in the Z direction between the antenna 110 and the indoor-side main surface 11A of the window glass 11 is preferably about 10 mm to 50 mm, and more preferably 20 mm to 30 mm.

[0056] The substrate 111 is formed of any material that is transparent to radio waves radiated from an outdoor base station and that can support the antenna 110. "Transparent to radio waves" means, for example, that the transmission loss is 10 dB or less. "Substrate 111 is transparent to the radiated radio waves" means that the transmission loss of substrate 111 is 10 dB or less, preferably 6 dB or less, more preferably 3 dB or less, and even more preferably 1 dB or less.

[0057] As an example, a glass plate is used for the substrate 111. Alternatively, a resin base material may be used for the substrate 111. Examples of resin materials that satisfy the above conditions include acrylic resins such as polymethyl methacrylate, cycloolefin resins, polycarbonate resins, and polyethylene terephthalate (PET).

[0058] The antenna 110 is made of a conductor. Since the antenna device 100 is arranged to overlap the window 10, the antenna 110 is made of a material such as zinc oxide (ZnO), tin oxide (SnO２ It is desirable that the antenna 110 be formed from a transparent conductive film such as tin-doped indium oxide (ITO) or indium oxide-tin oxide (IZO), a metal nitride such as titanium nitride (TiN) or chromium nitride (CrN), or a low-e (low emissivity) film for low-e glass. However, the antenna 110 may be formed from a metal thin film such as copper, nickel, or gold. In the case of a metal thin film, it is preferable to form it in a mesh shape from the viewpoint of visibility.

[0059] <Details of the Configuration of Antenna 110 and Spacing t> Next, details of the configuration of antenna 110 and spacing t will be described with reference to Fig. 3 in addition to Fig. 2. Fig. 3 is a diagram illustrating an example of details of the configuration of antenna 110 and spacing t.

[0060] The antenna 110 includes a substrate 111, adhesive layers 111A and 111B, sub-substrates 112A and 112B, an antenna element 113A, and a ground layer 113B. The sub-substrates 112A and 112B are examples of resin layers of the antenna 110 and are resin members. The antenna element 113A is an example of a radiating section, and the ground layer 113B is an example of a ground section. The antenna element 113A and the ground layer 113B are formed on a plurality of conductive layers. Of these, the substrate 111 is, as described above, a glass plate as an example here, but may also be the above-described resin base material.

[0061] Here, it is also conceivable to form the antenna element 113A and the ground layer 113B directly on the substrate 111. However, when forming conductor patterns such as the antenna element 113A and the ground layer 113B on the substrate 111, there are limitations on the degree of freedom of the pattern, and it is practically difficult to realize a complex structure such as a laminated structure. For these reasons, the antenna 110 has a configuration in which sub-substrates 112A and 112B, on which the antenna element 113A and the ground layer 113B are respectively formed, are attached to the substrate 111 with adhesive layers 111A and 111B. Each component will be described below.

[0062] The sizes of the substrate 111, the adhesive layers 111A and 111B, and the sub-substrates 112A and 112B in a plan view are, for example, equal to one another, and the outer edges of the substrate 111, the adhesive layers 111A and 111B, and the sub-substrates 112A and 112B in a plan view are, for example, coincident with one another. The outer edges of the substrate 111, the adhesive layers 111A and 111B, and the sub-substrates 112A and 112B in a plan view are the outer edges of the antenna 110 in a plan view.

[0063] The adhesive layers 111A and 111B bond the sub-substrates 112A and 112B to the surfaces of the substrate 111 on the −Z direction side and the +Z direction side, respectively.

[0064] As the adhesive layers 111A and 111B, for example, an OCA (Optical Clear Adhesive) made of an acrylic adhesive, a urethane adhesive, a rubber adhesive, or a silicone adhesive can be used. The adhesive layers 111A and 111B may be transparent to radio waves emitted from an outdoor base station. "Transparent to radio waves" means, for example, that the transmission loss is 10 dB or less. "The adhesive layers 111A and 111B are transparent to the radiated radio waves" means that the transmission loss of the adhesive layers 111A and 111B is 10 dB or less, preferably 6 dB or less, more preferably 3 dB or less, and even more preferably 1 dB or less.

[0065] The adhesive layers 111A and 111B may be transparent to visible light. "Transparent" to visible light means that the visual transmittance is at least 40% or more, preferably 60% or more, more preferably 70% or more, and even more preferably 80% or more.

[0066] The adhesive layers 111A and 111B preferably have a low dielectric loss tangent because they are used in the antenna device 100 that transmits and receives radio waves in the Sub-6 frequency band or millimeter wave band such as 5G. The thickness of the OCA used as the adhesive layers 111A and 111B is preferably 5 μm to 50 μm, particularly 10 μm to 35 μm, in terms of adhesion and durability.

[0067] Due to the nature of the OCA material, there is often a trade-off between low dielectric loss tangent and adhesive strength. In this embodiment, the OCA material is configured to achieve both low dielectric loss tangent and adhesive strength, which makes it suitable for use in the antenna device 100.

[0068] Sub-substrate 112A is attached to the surface on the -Z direction side of substrate 111 by adhesive layer 111A. Antenna element 113A is formed on the surface on the -Z direction side of sub-substrate 112A. Sub-substrate 112A is, for example, a flexible substrate, and can be formed from a flexible resin material such as polycarbonate, PET (Polyethylene terephthalate), fluororesin, COP (Cyclo-Olefin Polymer), PEN (Polyethylene naphthalate), polyimide, Peek (Polyether ether ketone), LCP (Liquid Crystal Polymer), or other composite materials.

[0069] For example, when the sub-substrate 112A is made of polycarbonate, the Young's modulus is preferably 1 GPa to 10 GPa, and more preferably 2000 MPa to 3.6 GPa.

[0070] The antenna element 113A is made of a conductor and is formed on the surface of the sub-substrate 112A on the −Z direction side. The antenna element 113A has, for example, a rectangular shape in a plan view, and together with the ground layer 113B, forms a patch antenna.

[0071] Since the antenna device 100 is disposed over the window glass 11, the antenna element 113A is made of zinc oxide (ZnO), tin oxide (SnO ２ It is desirable that the antenna element 113A be formed from a transparent conductive film such as tin-doped indium oxide (ITO) or indium oxide-tin oxide (IZO), a metal nitride such as titanium nitride (TiN) or chromium nitride (CrN), or a low-e (low emissivity) film for low-e glass. However, the antenna element 113A may be formed from a metal thin film such as copper, nickel, or gold. In the case of a metal thin film, it is preferable to form it in a mesh shape from the viewpoint of visibility.

[0072] Here, the distance between the surface of the matching layer 120 on the +Z direction side (indoor side) and the surface of the sub-substrate 112B on the +Z direction side (indoor side) is defined as t (see FIG. 3). The positional relationship using the distance t between the outer edge of the matching layer 120 and the outer edge of the antenna 110 in a plan view will be described later.

[0073] Sub-substrate 112B is attached to the surface on the +Z direction side of substrate 111 by adhesive layer 111B. A ground layer 113B is formed on the surface on the +Z direction side of sub-substrate 112B. As an example, sub-substrate 112B may be a flexible substrate similar to sub-substrate 112A, and may be made of a similar resin material.

[0074] Furthermore, the transmittance of the sub-substrate 112B for light with a wavelength of 380 nm is, for example, more than 5%. Because the matching layer 120 can absorb ultraviolet light, the sub-substrate 112B may have a low ultraviolet absorption rate. This increases the degree of freedom in selecting the material for the sub-substrate 112B.

[0075] Furthermore, when the sub-substrate 112B is made of polycarbonate, for example, the Young's modulus is preferably 1 GPa to 10 GPa, and more preferably 2000 MPa to 3.6 GPa.

[0076] The ground layer 113B is made of a conductor and is formed on the surface of the sub-substrate 112B on the +Z direction side. As the conductor constituting the ground layer 113B, for example, the same conductor as the conductor constituting the antenna element 113A can be used.

[0077] A plurality of ground layers 113B are provided, and overlap with a plurality of antenna elements 113A in a planar view. The number of ground layers 113B is equal to the number of antenna elements 113A. The ground layers 113B, together with the antenna elements 113A, form a patch antenna. For example, the ground layers 113B are rectangular in a planar view and are larger than the antenna elements 113A in a planar view. In a planar view, the outer edge of the ground layers 113B encompasses the outer edge of the antenna elements 113A.

[0078] Here, a configuration in which the antenna element 113A and the ground layer 113B constitute a patch antenna will be described. However, the antenna element 113A and the ground layer 113B are not limited to a patch antenna and may be a dipole antenna or the like. In this case, if the ground layer 113B is not necessary, the antenna 110 does not need to include the adhesive layer 111B, the sub-substrate 112B, and the ground layer 113B.

[0079] <Matching layer 120> As shown in Fig. 2, the matching layer 120 is a plate-like member held by a holder 160 attached to the indoor side of the window glass 11. As an example, the matching layer 120 is held by the holders 160 at its upper and lower ends. The matching layer 120 has a function of absorbing ultraviolet rays in order to suppress deterioration of the sub-substrates 112A and 112B, mainly due to ultraviolet rays. This will be described in detail later.

[0080] The matching layer 120 is disposed between the window glass 11 and the four antennas 110, and is held by a holder 160 at a predetermined distance from the window glass 11. The matching layer 120 has a surface facing the window glass 11 and a surface facing the indoor side. The surface of the matching layer 120 facing the window glass 11 is disposed at a predetermined distance from the indoor-side main surface 11A of the window glass 11.

[0081] The matching layer 120 is provided to adjust the electrical length of the radio waves incident on the antenna 110 and match the impedance. The matching layer 120 may be made of a material that has low loss with respect to the radio waves radiated from the outdoor base station. Low loss with respect to the radio waves means, for example, a transmission loss of 10 dB or less. The matching layer 120 having low loss with respect to the radiated radio waves means that the transmission loss of the matching layer 120 is 10 dB or less, preferably 6 dB or less, more preferably 3 dB or less, and even more preferably 1 dB or less.

[0082] The matching layer 120 may be transparent to visible light. "Transparent" to visible light means that the luminous transmittance is at least 40% or more, preferably 60% or more, more preferably 70% or more, and even more preferably 80% or more.

[0083] The matching layer 120 can be made of, for example, polycarbonate, acrylic, COP (cycloolefin polymer), PET (polyethylene terephthalate), polystyrene, or glass.

[0084] The matching layer 120 also contains an ultraviolet absorbing additive to absorb ultraviolet light. Examples of the ultraviolet absorbing additive include triazine-based, benzotriazole-based, and benzophenone-based polymer additives. The matching layer 120 can be a single-layer structure containing the ultraviolet absorbing additive.

[0085] The matching layer 120 has a transmittance of 5% or less for light having a wavelength of 380 nm, a relative dielectric constant ε of 2.0 or more and 7.0 or less at 4.5 GHz, and a dielectric loss tangent tanδ of 1.0×10 －５ Therefore, the matching layer 120 can absorb most of the ultraviolet light contained in sunlight that has passed through the window glass 11 .

[0086] From the viewpoint of suppressing bending, the matching layer 120 preferably has a thickness of 0.5 mm or more. If the matching layer 120 bends, the characteristics that adjust the electrical length of the radio waves may become non-uniform in the XY plane, which may cause variations in the degree of impedance matching. By having a thickness of 0.5 mm or more, the matching layer 120 is less likely to bend and can stand on its own.

[0087] The thickness of the matching layer 120 in the Z direction is, for example, constant throughout. From the viewpoint of increasing the luminous transmittance, the thickness of the matching layer 120 is preferably 20 mm or less, and more preferably 15 mm or less. Furthermore, the thickness of the matching layer 120 is, for example, even more preferably 0.5 mm to 5 mm. A matching layer 120 with sufficient thickness can more reliably absorb ultraviolet rays. The matching layer 120 may be a single layer, or may be a configuration in which multiple layers are stacked, or multiple layers are arranged at intervals.

[0088] The Young's modulus of the matching layer 120 is preferably, for example, 1 GPa to 100 GPa, which makes it possible to realize a matching layer 120 that is not easily bent and can stand on its own.

[0089] The matching layer 120 adjusts the electrical length of the radio waves incident on the antenna 110, and therefore its effective thickness varies depending on the dielectric constant. This is because the degree of the effect of shortening the wavelength of the radio waves varies depending on the dielectric constant. Therefore, from the perspective of matching the impedance of the radio waves, the effective thickness of the matching layer 120 should be set to an appropriate effective thickness that allows impedance matching.

[0090] Furthermore, the color difference ΔE between the transmitted color of the matching layer 120 and the transmitted color of the sub-substrates 112A and 112B of the antenna 110 is, for example, 1.5 or less, which can improve the chromaticity uniformity of the entire antenna 110 and the matching layer 120 combined.

[0091] Here, ΔE is the L standardized by CIE 1976. ＊ a ＊ b ＊ The L of two colors expressed by chromaticity coordinates in the color system ＊ a ＊ b ＊ ΔE=((ΔL ＊ ) ２ + (Δa ＊ ) ２ + (Δb ＊ ) ２ ) １／２ ΔE is calculated by converting the tristimulus values ​​XYZ of the XYZ color system measured in accordance with JIS Z8722:2009 into the ΔE of JIS Z8781-4:2013. ＊ ａｂ This is calculated from the formula:

[0092] Furthermore, the outer edge of the matching layer 120 is located outside the outer edge of the antenna 110 in a planar view in order to suppress deterioration of the sub-substrates 112A and 112B, mainly due to ultraviolet rays. The outer edge of the matching layer 120 being located outside the outer edge of the antenna 110 in a planar view means that the outer edge of the matching layer 120 encompasses the outer edge of the antenna 110 in a planar view. In other words, the matching layer 120 is larger than the antenna 110 in a planar view. Details of this configuration will be described later using Figures 6A and 6B.

[0093] <Holder 160> As shown in Fig. 2, the holder 160 is attached to the indoor main surface 11A of the window glass 11, and holds, for example, the upper and lower ends of the matching layer 120. The holder 160 is made of transparent glass or resin. "Transparent" here means being transparent to visible light. Note that the holder 160 is not limited to a configuration that holds the upper and lower ends of the matching layer 120, and may be configured to hold, for example, the +X direction side and the -X direction side.

[0094] The holder 160 holds the antenna 110 and the matching layer 120, and holds the matching layer 120 at a predetermined distance from the window glass 11. The predetermined distance is the distance between the main surface 11A of the window glass 11 on the indoor side and the surface on the window glass 11 side.

[0095] <Radio Device 210> The radio device 210 will be described using Fig. 4 in addition to Fig. 2. Fig. 4 is a diagram showing an example of the circuit configuration of the radio device 210. Fig. 4 shows the configuration of a portion of the overall configuration of the radio device 210 that corresponds to one antenna 110. The antenna 110 is connected to the radio device 210 via a waveguide 170.

[0096] If the distance between the antenna 110 and the wireless device 210 is long, the transmission loss of radio waves between the antenna 110 and the wireless device 210 increases. Therefore, in order to reduce the transmission loss of radio waves, it is preferable to attach the wireless device 210 to the window glass 11 or to the wall 1A or ceiling around the window 10.

[0097] Furthermore, in order to reduce transmission loss of radio waves between antenna 110 and wireless device 210, a bendable waveguide 170 is used, as an example, as a transmission path connecting antenna 110 and wireless device 210. By using bendable waveguide 170, radio waves can be propagated efficiently between antenna 110 and wireless device 210 with little transmission loss.

[0098] The wireless device 210 includes a wireless module 211, a switch 212, a low noise amplifier (LNA) 213, a mixer 214, an analog to digital converter (ADC) 215, a digital to analog converter (DAC) 216, a mixer 217, and a power amplifier (PA) 218. The wireless module 211 to the PA 218 are an example of a wireless communication unit of the wireless device 210.

[0099] Of the wireless device 210, the switch 212, the LNA 213, the mixer 214, the ADC 215, the DAC 216, the mixer 217, and the PA 218 are provided one for each antenna 110. The wireless device 210 includes the same number of components from the switch 212 to the PA 218 as the number of antennas 110. As an example, there is one wireless module 211 that is common to the four antennas 110.

[0100] The wireless module 211 is configured, for example, by an MCU (Micro Controller Unit), and includes a control unit 211A and a relay unit 211B that performs relay processing. The control unit 211A and the relay unit 211B are functional blocks that represent the functions executed by the MCU.

[0101] When receiving radio waves through antenna 110, control unit 211A switches three-terminal switch 212 to connect antenna 110 to LNA 213. When transmitting radio waves through antenna 110, control unit 211A switches three-terminal switch 212 to connect antenna 110 to PA 218.

[0102] The relay unit 211B includes, as an example, a Bluetooth (registered trademark) communication unit, is connected to the array antenna 210A, and transmits a digital signal input from the ADC 215 from the array antenna 210A to the inside of the building 1. When the relay unit 211B transmits a signal to the inside of the building 1 via the array antenna 210A, the radio waves received by the antenna 110 from the base station BS are relayed, and the radio waves are radiated to the inside of the building 1 where the wireless communication device 200 is located. As a result, the radio waves are radiated over a wide area inside the building 1, making it easier for terminals such as the smartphone 60 located indoors to receive the radio waves. Note that the communication unit that radiates the radio waves relayed indoors by the relay unit 211B is not limited to Bluetooth, and may be Wi-Fi or the like.

[0103] The LNA 213 is provided between the switch 212 and the mixer 214, and amplifies the radio waves received by the antenna 110 and outputs them while preventing degradation of the signal-to-noise ratio.

[0104] The mixer 214 demodulates the radio wave output from the LNA 213 by mixing it with a local signal (LO) and outputs an intermediate frequency (IF) signal. By converting the signal into an IF signal, digital conversion can be easily performed by the ADC 215.

[0105] The ADC 215 converts the IF signal output from the mixer 214 into a digital signal and outputs the digital signal to the wireless module 211 .

[0106] When the wireless communication device 200 transmits a signal from the antenna 110 , the DAC 216 converts the signal output by the wireless module 211 into an analog signal and outputs the IF signal to the mixer 217 .

[0107] The mixer 217 mixes the IF signal with a local signal (LO) to modulate it, and outputs the modulated signal to the PA 218 .

[0108] The PA 218 amplifies the signal output from the mixer 217 and outputs the amplified signal to the antenna 110 via the switch 212 .

[0109] When the radio waves handled by radio device 210 are Sub-6, radio device 210 may not include mixers 214 and 217. In this case, the signal input to ADC 215 and the signal output from DAC 216 are not IF signals but signals in the Sub-6 frequency band.

[0110] <Sunlight Entering Through Window Glass 11 and Solar Altitude> Figure 5 is a diagram illustrating an example of the relationship between sunlight entering the interior of a building after passing through window glass 11 provided in a window 10 of building 1 and the solar altitude. Figure 5 shows, as an example, building 1 located in Tokyo, with the left side facing south (S) and the right side facing north (N).

[0111] 5 shows the position of the sun at noon on the summer solstice, vernal equinox, autumnal equinox, and winter solstice in Tokyo, and the sunlight passing through window glass 11 and entering the building. The sunlight at the summer solstice is shown by a solid line, the sunlight at the vernal equinox and autumnal equinox by a dashed line, and the sunlight at the winter solstice by a dashed-dotted line. The solar altitude at noon on the summer solstice in Tokyo is 78.5°, the solar altitude at noon on the vernal equinox and autumnal equinox in Tokyo is 54.9°, and the solar altitude at noon on the winter solstice in Tokyo is 31.6°.

[0112] 6A is a diagram illustrating an example of sunlight incidence on the comparative antenna device 30. The comparative antenna device 30 has a configuration in which the matching layer 120 is omitted from the antenna device 100 of the embodiment.

[0113] 6A shows the window glass 11, with the left side facing south (S) and the right side facing north (N). Fig. 6A also shows the position of the sun at noon during a certain time of year, and sunlight (indicated by a solid arrow) passing through the window glass 11 and entering the interior of the building.

[0114] 6A, the antenna 110 of the comparative antenna device 30 is directly exposed to sunlight that has passed through the window glass 11. The sub-substrates 112A and 112B of the antenna 110 are made of a resin material and are therefore subject to deterioration by ultraviolet rays contained in the sunlight.

[0115] Furthermore, since sunlight is incident on the window glass 11 at an angle, the incidence of sunlight on the sub-substrates 112A and 112B is not limited to the surface (main surface) on the -Z direction side, but can also occur on the end surface (upper end surface) on the +Y direction side as shown in Figure 6A.

[0116] On the winter solstice, the sun's altitude is low, so sunlight has difficulty reaching the inside of the sub-substrates 112A and 112B, but when the sun's altitude is high, such as on the summer solstice, sunlight penetrates into the inside of the sub-substrates 112A and 112B. On the vernal and autumnal equinoxes, sunlight also penetrates into the sub-substrates 112A and 112B to a certain extent.

[0117] Of the four side surfaces corresponding to the four sides of the sub-substrates 112A and 112B in a plan view, the surface through which sunlight is most likely to penetrate is the end surface (top end surface) on the +Y direction side. When the sun is tilting, such as in the morning and evening, sunlight can penetrate into the interiors of the sub-substrates 112A and 112B from the end surface on the +X direction side and the end surface on the −X direction side. Reflected light can also penetrate into the interiors of the sub-substrates 112A and 112B from the end surface on the −Y direction side (bottom end surface).

[0118] When sunlight penetrates into the sub-substrates 112A and 112B in this way, ultraviolet rays cause deterioration of the sub-substrates 112A and 112B. Deterioration of the sub-substrates 112A and 112B can affect the radiation characteristics of a patch antenna or the like formed by the antenna element 113A and the ground layer 113B.

[0119] Furthermore, if the substrate 111 is made of a resin base material, the substrate 111 may also be deteriorated by ultraviolet rays contained in sunlight. Furthermore, sunlight may enter the substrate 111 from the end face (top end face) on the +Y direction side, the end face on the +X direction side, the end face on the −X direction side, and the end face (bottom end face) on the −Y direction side. As a result, the radiation characteristics of the patch antenna or the like may be affected.

[0120] Furthermore, the adhesive layers 111A and 111B of the antenna 110 are made of the OCA material described above, which absorbs ultraviolet rays and may be degraded by ultraviolet rays. Sunlight may also penetrate the adhesive layers 111A and 111B from the end faces (top end faces) on the +Y direction side, the +X direction side, the −X direction side, and the −Y direction side (bottom end faces). This may affect the radiation characteristics of the patch antenna, etc.

[0121] <UV Protection Using Matching Layer 120 of Antenna Device 100 of Embodiment> Fig. 6B is a diagram showing an example of the state of sunlight incident on the antenna device 100 of the embodiment. Like Fig. 6A, Fig. 6B shows the window glass 11, with the left side facing south (S) and the right side facing north (N). Also, like Fig. 6A, it shows the position of the sun at noon during a certain time of year and sunlight (indicated by a solid arrow) passing through the window glass 11 and entering the room.

[0122] As described above, the matching layer 120 has the function of absorbing ultraviolet rays. For example, the transmittance of light with a wavelength of 380 nm is 5% or less, so that the ultraviolet rays are almost entirely absorbed by the matching layer 120 .

[0123] 6B , sunlight passing outside the outer edge of matching layer 120 may be incident on the +Y side end face of antenna 110. This phenomenon may also occur on the +X side end face, the −X side end face, and the −Y side end face of antenna 110.

[0124] 6B , the upper end (the end on the +Y direction side) of the matching layer 120 is located higher than the upper end of the antenna 110. In other words, the upper end of the matching layer 120 extends higher than the upper end of the antenna 110.

[0125] The reason for extending the upper end of the matching layer 120 upward in this manner is to position the matching layer 120 on the optical path of the sunlight, thereby reducing the amount of sunlight and suppressing the amount of light that enters the antenna 110. Reducing the amount of sunlight that enters the antenna 110 reduces the amount of ultraviolet light that enters the antenna 110.

[0126] As described above, sunlight is most likely to penetrate the end face on the +Y direction side of antenna 110, but sunlight can also penetrate from the end face on the +X direction side, the -X direction side, or the -Y direction side. For this reason, the outer edge of matching layer 120 only needs to be located outside the end (outer edge) of antenna 110 in a plan view on the end face on the +X direction side, the -X direction side, and the -Y direction side other than the end face on the +Y direction side.

[0127] Furthermore, although the following description is given of a configuration in which the antenna 110 has a rectangular shape in a plan view, the same applies to various shapes, such as shapes with curved sides. That is, the outer edge of the matching layer 120 may be located further outward than the outer edge of the antenna 110 in a plan view. When the outer edge of the antenna 110 is curved in a plan view, the portion of the outer edge of the antenna 110 corresponding to the end face on the +Y direction side described above is the portion of the outer edge of the antenna 110 that is directly visible when viewed vertically from above. For example, when the outer edge of the antenna 110 is circular in a plan view, the portion of the outer edge of the antenna 110 corresponding to the end face on the +Y direction side described above is the semicircular portion of the circular outer edge that is directly visible when viewed vertically from above.

[0128] Here, how far above the antenna 110 the upper end of the matching layer 120 should be positioned will be described with reference to Fig. 6C. Fig. 6C is a diagram for explaining an example of calculation of the position of the upper end of the matching layer 120.

[0129] 6C shows only the matching layer 120, the sub-substrate 112B, and the ground layer 113B, omitting other components. The distance t is the distance between the surface of the matching layer 120 on the +Z direction side (indoor side) and the surface of the sub-substrate 112B on the +Z direction side (indoor side).

[0130] Here, we consider sunlight at noon on the summer solstice (see arrow) in Tokyo as the most severe condition for sunlight to be incident on the end face on the +Y direction side of sub-substrate 112B. We consider that the amount of sunlight is reduced by matching layer 120. Of the end faces of sub-substrates 112A and 112B, substrate 111, and adhesive layers 111A and 111B (see FIG. 6B) that may be made of resin among the components of antenna 110, the end face of sub-substrate 112B that is farthest from matching layer 120 is the one through which sunlight is most likely to penetrate. For this reason, sub-substrate 112B is shown in FIG. 6C.

[0131] Here, we calculate the conditions under which sunlight that has grazed the +Z-direction corner of the upper end (end on the +Y-direction side) of matching layer 120 does not pass through the inside of sub-substrate 112B when it is incident as shown by the arrow. The strictest condition for not passing through the inside of sub-substrate 112B is the condition under which it does not pass through the +Z-direction end of the end surface on the +Y-direction side of sub-substrate 112B.

[0132] In the YZ plane view, the angle θ between the surface of the matching layer 120 on the +Z direction side and the sunlight at noon on the summer solstice in Tokyo is 11.5°. This is because the solar altitude at noon on the summer solstice in Tokyo is 78.5°.

[0133] If the length in the Y direction from the upper end (end on the +Y direction side) of the sub-substrate 112B to the upper end of the matching layer 120 is defined as Y1, then Y1 can be calculated as follows: Y1=t / tan 11.5°≈5t

[0134] Therefore, in order to prevent sunlight at noon on the summer solstice in Tokyo from passing through the end face of the sub-substrate 112B on the +Y direction side without passing through the matching layer 120, the upper end of the matching layer 120 should be positioned approximately 5t above the upper end of the sub-substrate 112B.

[0135] In addition, the solar altitude at noon on the summer solstice in New York City is 72.7°. In this case, Y1 takes the following value: Y1 = t / tan 18.3° ≒ 3t

[0136] From the above, using the above-mentioned distance t (the distance between the surface of matching layer 120 on the +Z direction side and the surface of sub-substrate 112B on the +Z direction side), and taking the solar altitude at noon on the summer solstice in Tokyo as a reference, the upper end of matching layer 120 should be positioned 5t or more above (outside) the upper end of sub-substrate 112B. Also, taking the solar altitude at noon on the summer solstice in New York City, USA as a reference, the upper end of matching layer 120 should be positioned 3t or more above (outside) the upper end of sub-substrate 112B.

[0137] In such a case, it is sufficient that at least a portion of the upper end of the matching layer 120, rather than the entire upper end of the matching layer 120 as described above, is positioned 3t or more above (outside) the upper end of the sub-substrate 112B, because this can prevent ultraviolet rays from penetrating the sub-substrate 112B.

[0138] Furthermore, the outer edges of the matching layer 120 on the +X, −X, and −Y sides other than the +Y side may also be positioned further outward than the outer edge of the sub-substrate 112B in a planar view. This is to reduce the penetration of reflected light and the like into the sub-substrate 112B. Using the thickness t described above, the outer edges of the matching layer 120 on the +X, −X, and −Y sides may be positioned 2t or more outward from the corresponding outer edges of the sub-substrate 112B in a planar view. Note that the +X and −X side outer edges of the matching layer 120 may be positioned further outward than the +X and −X side outer edges of the sub-substrate 112B in a planar view, while the −Y side outer edge of the matching layer 120 may not be positioned further outward than the −Y side outer edge of the sub-substrate 112B.

[0139] In order to reduce the incidence of sunlight from the end face of the sub-substrate 112B, the antenna device 100 of this embodiment is configured so that the outer edge of the matching layer 120 is larger than and located further outward than the outer edge of the antenna 110 in a planar view. Having the outer edge of the matching layer 120 larger than and located further outward than the outer edge of the antenna 110 in a planar view means that the outer edge of the matching layer 120 encompasses the outer edge of the antenna 110 in a planar view. Ultraviolet rays contained in sunlight that have passed through the window glass 11 can be absorbed by the matching layer 120 before they reach the antenna 110, and the incidence of ultraviolet rays from the end face of the antenna 110 in particular can be suppressed.

[0140] If the antenna 110 does not have the sub-substrate 112B and the ground layer 113B, the outer edge of the matching layer 120 may be located outside the outer edge of the sub-substrate 112A in a planar view. In this case, at least a part of the outer edge of the matching layer 120 may be located outside the outer edge of the sub-substrate 112A in a planar view.

[0141] <Matching Layer 120A of a Modified Example of the Embodiment> Figure 7 is a diagram showing an example of the cross-sectional configuration of a matching layer 120A according to a modified example of the embodiment. The matching layer 120A includes a polycarbonate base 121 and, for example, an ultraviolet absorbing layer 122 formed on the main surface of the base 121 on the -Z direction side. For example, the ultraviolet absorbing layer 122 is also formed on the end surfaces of the base 121 on the +Y direction side, the -Y direction side, the +X direction side, and the -X direction side. This allows for the matching layer 120A to have a two-layer structure including the ultraviolet absorbing layer 122. Furthermore, by forming the ultraviolet absorbing layer 122 on the end surfaces as well, resin members such as the sub-substrate 112B can be more reliably protected from ultraviolet rays.

[0142] As an example, the ultraviolet absorbing layer 122 may be formed on some of the end faces of the base 121 on the +Y direction side, the −Y direction side, the +X direction side, and the −X direction side, or may not be formed on the end faces of the base 121 on the +Y direction side, the −Y direction side, the +X direction side, and the −X direction side.

[0143] The substrate 121 is a thin plate-like member made of polycarbonate, acrylic, or glass, and is preferably transparent. Here, "transparent" means transparent to visible light. "Transparent" to visible light means that the luminous transmittance is at least 40% or more, preferably 60% or more, more preferably 70% or more, and even more preferably 80% or more.

[0144] The ultraviolet absorbing layer 122 is, for example, a transparent resin layer containing an ultraviolet absorbing additive. Examples of resin materials include PET and polyol. Examples of the ultraviolet absorbing additive include triazine-based, benzotriazole-based, or benzophenone-based polymer additives. The ultraviolet absorbing layer 122 may be coated on the base 121, or may be attached to the base 121 using an adhesive layer. When coating the ultraviolet absorbing layer 122, wet coating is preferred.

[0145] The ratio of the thickness of the ultraviolet absorbing layer 122 in the Z direction to the thickness of the base 121 in the Z direction is, for example, 1 / 1000 to 1 / 100. The ultraviolet absorbing layer 122 having an appropriate thickness can absorb ultraviolet rays.

[0146] As an example, the ultraviolet absorbing layer 122 may be formed on the main surface of the base 121 on the +Z direction side, and may also be formed on at least a portion of the end surface of the base 121.

[0147] <Effects> The antenna device 100 includes an antenna 110 disposed opposite the main surface 11A of the window glass 11, and a matching layer 120 provided between the window glass 11 and the antenna 110. The matching layer 120 has a transmittance of 5% or less for light having a wavelength of 380 nm, a relative dielectric constant ε at 4.5 GHz of 2.0 or more and 7.0 or less, and a dielectric loss tangent tanδ of 1.0×10 －５ Therefore, the matching layer 120 can absorb most of the ultraviolet light contained in sunlight that has passed through the window glass 11 .

[0148] Therefore, it is possible to provide the antenna device 100 that can protect the resin member of the antenna 110 from ultraviolet rays.

[0149] Furthermore, the outer edge of the matching layer 120 may be located outside the outer edge of the antenna 110 in a plan view. By having the outer edge of the matching layer 120 encompass the outer edge of the antenna 110 in a plan view, it is possible to provide an antenna device 100 that can more reliably protect the resin member of the antenna 110 from ultraviolet rays by having the matching layer 120 absorb ultraviolet rays before they reach the antenna 110.

[0150] Furthermore, the antenna 110 has a sub-substrate 112B (resin layer), and when the distance between the indoor surface of the matching layer 120 and the indoor surface of the sub-substrate 112B is t, at least a part of the outer edge of the matching layer 120 may be located 3t or more outside the outer edge of the antenna 110 in a planar view. Taking into account the harshest conditions throughout the year, namely, the time of solar noon on the summer solstice, it is possible to provide an antenna device 100 that can more reliably protect resin members such as the sub-substrate 112B of the antenna 110 from ultraviolet rays. The matching layer 120 may also be located 5t or more outside the outer edge of the antenna 110 in a planar view.

[0151] The thickness of the matching layer 120 may be 0.5 mm to 5 mm. With a matching layer 120 of sufficient thickness, it is possible to provide an antenna device 100 that can more reliably protect the resin member of the antenna 110 from ultraviolet rays.

[0152] The Young's modulus of the matching layer 120 may be 1 GPa or more and 100 GPa or less. The matching layer 120 is hard to bend and can stand on its own, making it possible to provide the antenna device 100 that can more reliably protect the resin members such as the sub-substrate 112B of the antenna 110 from ultraviolet rays.

[0153] The matching layer 120 is made of polycarbonate, acrylic, or glass, and may contain an ultraviolet absorbing additive. The single-plate matching layer 120 containing the ultraviolet absorbing additive can provide the antenna device 100 that can more reliably protect the resin components, such as the sub-substrate 112B of the antenna 110, from ultraviolet rays.

[0154] Furthermore, the matching layer 120A may include a polycarbonate base 121 and an ultraviolet absorbing layer 122 formed on the main surface of the base 121. The matching layer 120 has a two-layer structure including the ultraviolet absorbing layer 122, making it possible to provide the antenna device 100 that can more reliably protect resin members such as the sub-substrate 112B of the antenna 110 from ultraviolet rays.

[0155] The ultraviolet absorbing layer 122 may also be formed on a part of the end surface of the base 121. By absorbing ultraviolet rays incident on the end surface connecting the two main surfaces of the base 121, it is possible to provide an antenna device 100 that can more reliably protect resin members such as the sub-substrate 112B of the antenna 110 from ultraviolet rays.

[0156] The ratio of the thickness of the ultraviolet absorbing layer 122 to the thickness of the base 121 may be 1 / 1000 to 1 / 100. By absorbing ultraviolet rays with the ultraviolet absorbing layer 122 having an appropriate thickness, it is possible to provide the antenna device 100 that can more reliably protect the resin members such as the sub-substrate 112B of the antenna 110 from ultraviolet rays.

[0157] Furthermore, the transmittance of the sub-substrate 112B (resin layer) for light with a wavelength of 380 nm may be greater than 5%. Because the matching layer 120 can absorb ultraviolet light, the sub-substrate 112B (resin layer) may have a low ultraviolet absorption rate, which allows for greater freedom in selecting the material for the sub-substrate 112B (resin layer), making it possible to provide an antenna device 100 that can more reliably protect resin members such as the sub-substrate 112B from ultraviolet light.

[0158] The luminous transmittance of the matching layer 120 may be 40% to 90%, thereby providing an antenna device 100 in which the matching layer 120 is less noticeable.

[0159] Furthermore, the luminous transmittance of the sub-substrate 112B (resin layer) of the antenna 110 may be 40% to 90%, thereby providing an antenna device 100 in which the sub-substrate 112B (resin layer) is less noticeable.

[0160] The Young's modulus of the sub-substrate 112B (resin layer) of the antenna 110 may be 1 GPa to 10 GPa. The sub-substrate 112B (resin layer) is relatively hard, which makes it easy to form a conductive layer.

[0161] The color difference ΔE between the transmitted color of the matching layer 120 and the transmitted color of the sub-substrate 112B (resin layer) of the antenna 110 may be 1.5 or less, thereby providing an antenna device 100 with improved chromaticity uniformity as a whole, including the antenna 110 and the matching layer 120.

[0162] The communication frequency of the antenna 110 may be a part of the range from 600 MHz to 50 GHz. It is possible to provide an antenna device 100 that can transmit and receive radio waves in frequency bands such as Sub-6 and the fifth generation mobile communication system (5G) and can protect the resin member of the antenna 110 from ultraviolet rays.

[0163] The antenna 110 may also have multiple conductive layers (antenna element 113A, ground layer 113B). This makes it possible to provide an antenna device 100 that can protect multiple resin members (sub-substrates 112A and 112B) on which the multiple conductive layers (antenna element 113A, ground layer 113B) are formed from ultraviolet rays.

[0164] The plurality of conductive layers may include an outdoor-side conductive layer on which the radiation portion (antenna element 113A) is formed, and an indoor-side conductive layer that is disposed closer to the indoor side than the outdoor-side conductive layer and on which the ground portion (ground layer 113B) is formed. It is possible to provide an antenna device 100 that can protect the resin member (sub-substrate 112A) on which the outdoor-side conductive layer is formed and the resin member (sub-substrate 112B) on which the outdoor-side conductive layer is formed from ultraviolet rays.

[0165] The wireless communication device 200 includes the above-described antenna device 100, a waveguide 170 (transmission path) connected to the antenna device 100, and a wireless device 210 (wireless communication unit) connected to the antenna device 100 via the transmission path, and the waveguide 170 (transmission path) is connected to a portion of the antenna device 100 opposite to the window glass 11 side. Therefore, the matching layer 120 can absorb most of the ultraviolet rays contained in sunlight that has passed through the window glass 11.

[0166] Therefore, it is possible to provide a wireless communication device 200 that can protect the resin member of the antenna 110 from ultraviolet rays.

[0167] The above describes exemplary antenna devices and wireless communication devices of the present disclosure, but the present disclosure is not limited to the specifically disclosed embodiments, and various modifications and variations are possible without departing from the scope of the claims.

[0168] This international application claims priority based on Japanese Patent Application No. 2023-102005, filed on June 21, 2023, the entire contents of which are incorporated herein by reference.

[0169] 1 Building 1A Wall 10 Window 11 Window glass 12 Window frame 100 Antenna device 110 Antenna 111 Substrate 111A, 111B Adhesive layer 112A, 112B Sub-substrate (resin layer, an example of a resin member) 113A Antenna element (an example of a radiation portion) 113B Ground layer (an example of a ground portion) 120, 120A Matching layer 121 Base 122 Ultraviolet absorbing layer 160 Holder (an example of a holding portion) 170 Waveguide (an example of a transmission path) 200 Wireless communication device 210 Wireless device (an example of a wireless communication portion)

Claims

1. An antenna disposed opposite the main surface of a window glass; and a matching layer provided between the window glass and the antenna, wherein the matching layer has a transmittance of 5% or less for light having a wavelength of 380 nm, a relative dielectric constant ε of 2.0 or more and 7.0 or less at 4.5 GHz, and a dielectric loss tangent tan δ of 1.0×10 －５ An antenna device having a size of 0.1 or less.

2. The antenna device according to claim 1, wherein an outer edge of the matching layer is located outside an outer edge of the antenna in a plan view.

3. An antenna device as described in claim 1 or 2, wherein the antenna has a resin layer, and where t is the distance between the indoor surface of the matching layer and the indoor surface of the resin layer, at least a part of the outer edge of the matching layer is located 3t or more outboard from the outer edge of the antenna in a planar view.

4. An antenna device according to any one of claims 1 to 3, wherein the matching layer has a thickness of 0.5 mm to 5 mm.

5. An antenna device according to any one of claims 1 to 4, wherein the Young's modulus of the matching layer is not less than 1 GPa and not more than 100 GPa.

6. The antenna device of any one of claims 1 to 5, wherein the matching layer is made of polycarbonate, acrylic, or glass and contains an ultraviolet absorbing additive.

7. The antenna device according to any one of claims 1 to 5, wherein said matching layer includes a polycarbonate substrate and an ultraviolet absorbing layer formed on a main surface of said substrate.

8. The antenna device according to claim 7, wherein the ultraviolet absorbing layer is also formed on a portion of the end face of the base.

9. The antenna device according to claim 8, wherein the ratio of the thickness of said ultraviolet absorbing layer to the thickness of said base is 1 / 1000 to 1 / 100.

10. The antenna device according to claim 3, wherein the transmittance of said resin layer for light having a wavelength of 380 nm is greater than 5%.

11. An antenna device according to any one of claims 1 to 10, wherein the luminous transmittance of the matching layer is between 40% and 90%.

12. An antenna device as described in claim 3 or 10, wherein the resin layer of the antenna has a visual transmittance of 40% to 90%.

13. The antenna device according to claim 3, wherein the Young's modulus of the resin layer of the antenna is 1 GPa to 10 GPa.

14. The antenna device according to claim 10, wherein the color difference ΔE between the transmitted color of said matching layer and the transmitted color of said resin layer of said antenna is 1.5 or less.

15. An antenna device according to any one of claims 1 to 14, wherein the communication frequency of the antenna is a portion of the range from 600 MHz to 50 GHz.

16. The antenna device according to any one of claims 1 to 15, wherein the antenna has a plurality of conductive layers.

17. An antenna device as described in claim 16, wherein the plurality of conductive layers include an outdoor-side conductive layer on which a radiating portion is formed, and an indoor-side conductive layer arranged on the indoor side relative to the outdoor-side conductive layer and on which a ground portion is formed.

18. A wireless communication device comprising: an antenna device as claimed in any one of claims 1 to 17; a transmission path connected to the antenna device; and a wireless communication unit connected to the antenna device via the transmission path, wherein the transmission path is connected to a portion of the antenna device opposite the window glass side.