Transparent antenna, antenna array, and display module

Abstract

A transparent antenna that can communicate in at least two 5G bandwidths, and that has a reduced antenna thickness.　A transparent antenna provided with a transparent substrate and a metal thin line layer on the upper side of the transparent substrate, wherein: the transparent substrate has a thickness of not more than 200 μm; the metal thin line layer has a porosity of at least 80%; and, if the input reflectance coefficient S11 of a metal conductor having a surface resistivity ρ[Ω / sq] at a frequency of f[GHz] when placed in parallel with the antenna at a distance of 0.15 mm is defined as S11(ρ,f), and the radiation efficiency is defined as Eff(ρ,f)[%], at two frequencies f1, f2 between 2GHz < f < 50GHz, S11(0.1[Ω / sq], f1[GHz]) < -10[dB], S11(0.1[Ω / sq], f2[GHz]) < -10[dB], and | Eff(0.1[Ω / sq], f1[GHz]) - Eff(0.1[Ω / sq], f2[GHz]) | < 25%.

Description

[Technical Field]

[0001] The present invention relates to a transparent antenna, an antenna array, and a display module including a transparent antenna. [Background technology]

[0002] In recent years, the fifth generation mobile communication system (5G) or sixth generation mobile communication system (6G) has been developed as a communication technology for mobile communication devices such as smartphones, tablets, mobile phones, and laptops.

[0003] Here, millimeter waves, known as fifth-generation mobile communication systems (5G), are highly directional, have a relatively short reach, and are easily blocked by metal, etc., so technology has been proposed for 5G antennas in which transparent antennas are placed on displays (OLED, LCD, LED) or touch panels (including display-integrated metal thin-wire panels) (for example, Patent Document 1 and Patent Document 2).

[0004] Meanwhile, for the fifth-generation mobile communication system (5G), for example, some countries have allocated two or more bands. The allocated frequencies vary slightly depending on the country, but for example, two bands, 24.2 to 29.5 GHz and 37.3 to 40 GHz, or two bands, 3.3 to 5.0 GHz and 24.2 to 29.5 GHz, are allocated. Therefore, there is a demand for transparent antennas for mobile communication devices in recent years that can be placed on displays and are compatible with multiple bands. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2013-5013 [Patent Document 2] US Publication No. 2019 / 0058264 Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the technologies of Patent Document 1 and Patent Document 2, the antenna elements of any of the transparent antennas are patch antennas including a planar element formed of a mesh and a ground layer. However, the patch antenna requires a ground layer on the back surface facing the antenna pattern. Here, in the patch antenna, since the antenna characteristics are better when the ground layer is separated from the layer of the antenna pattern, the substrate in the patch antenna was thick within the mountable range.

[0007] Also, in the technologies of Patent Document 1 and Patent Document 2, single-band antennas that communicate only in one band are disclosed, and communication in two or more frequency bands in the 5G frequency band has not been studied.

[0008] Therefore, in view of the above circumstances, an object of the present invention is to provide a transparent antenna that can communicate in at least two bands of 5G and can reduce the antenna thickness.

Means for Solving the Problems

[0009] To solve the above problems, in one aspect of the present invention, a transparent antenna including a transparent base material and a metal fine wire layer on the upper side of the transparent base material, the transparent base material has a thickness of 200 μm or less, the metal fine wire layer has an aperture ratio of 80% or more, When the input reflection coefficient S11 at the frequency of f [GHz] when a metal conductor with a surface resistivity ρ [Ω / sq] is placed in parallel with the antenna at a distance of 0.15 mm is written as S11(ρ,f) and the radiation efficiency is written as Eff(ρ,f) [%], at two frequencies f1 and f2 between 2 GHz < f < 50 GHz, S11(0.1 [Ω / sq], f1 [GHz]) < -3 [dB] S11(0.1 [Ω / sq], f2 [GHz]) < -3 [dB] |Eff(0.1[Ω / sq],f1[GHz])-Eff(0.1[Ω / sq],f2[GHz])|<25% A transparent antenna is provided. [Effects of the Invention]

[0010] According to one embodiment, the transparent antenna is capable of communication in at least two 5G bands and allows for a thin antenna thickness. [Brief explanation of the drawings]

[0011] [Figure 1] An overall view of an electronic device with a display and a diagram showing the position of the transparent antenna. [Figure 2] 2 is a cross-sectional view of the electronic device of FIG. 1 taken along the line AA. [Figure 3] FIG. 1 is an exploded cross-sectional view showing details of the display module. [Figure 4] FIG. 1 is a diagram showing frequency bands allocated to 5G in each country and examples of bands for the transparent antenna of the present invention. [Figure 5] 1 is a perspective view of a transparent antenna according to a first configuration example of the present invention. [Figure 6] 1A and 1B are a top view and a bottom view, respectively, of a transparent antenna according to a first configuration example. [Figure 7] 1 is an explanatory diagram of a transparent conductor of a transparent antenna of the present invention. [Figure 8] FIG. 10 is a diagram showing a pseudo display module in which the first transparent antenna of the present invention is sandwiched between a transparent cover and a resistor that resembles a display. [Figure 9] 9 is a diagram showing the S11 parameter characteristic value when the resistance value of the resistor simulating the lower display in the pseudo display module of FIG. 8 is changed. [Figure 10] FIG. 10 is a perspective view of a transparent antenna according to a second configuration example of the present invention. [Figure 11] 10A and 10B are a top view and a bottom view, respectively, of a transparent antenna according to a second configuration example. [Figure 12] FIG. 10 is a perspective view of a transparent antenna according to a comparative example. [Figure 13]1A and 1B are a top view and a bottom view, respectively, of a transparent antenna according to a comparative example. [Figure 14] 10 is a graph showing the radiation coefficient and radiation efficiency of the transparent antennas of the first and second configuration examples of the present invention and the comparative example. FIG. [Figure 15] FIG. 10 is a perspective view of a transparent antenna according to a third configuration example of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following, identical components will be designated by the same reference numerals, and duplicated explanations may be omitted. Hereinafter, embodiments of the present invention that apply a transparent antenna will be described.

[0013] The transparent antenna 100 of the present invention is applicable to, for example, a fifth generation mobile communication system (5G) or a sixth generation mobile communication system (6G).

[0014] <Electronic equipment> 1 and 2, the configuration of an electronic device 200, which is an example of a communication device equipped with a display module D including a transparent antenna 100 of the present invention, will be described. FIG. 1 is an overall view of the electronic device 200 equipped with a display module D of the present invention and a diagram showing the position of the transparent antenna 100. FIG. 2 is a cross-sectional view of the A-side of the electronic device 200 of FIG. 1.

[0015] 1 and 2, the X direction indicates the horizontal direction of the electronic device 200, the Y direction indicates the vertical direction of the electronic device 200, and the Z direction indicates the height direction of the electronic device 200. In the following, an XYZ coordinate system is defined and explained. For convenience of explanation, a planar view refers to an XY plane view, and explanations are given using a vertical direction in which the +Z direction side is the upper side and the -Z direction side is the lower side, and a horizontal direction (side) relative to the vertical direction, but these do not represent universal vertical and horizontal directions.

[0016] Furthermore, deviations in directions such as parallel, right-angled, orthogonal, horizontal, vertical, up-down, left-right, etc. are permitted to the extent that they do not impair the effects of the disclosure in the embodiments. Furthermore, the X direction, Y direction, and Z direction represent directions parallel to the X axis, Y axis, and Z axis, respectively. The X direction, Y direction, and Z direction are perpendicular to each other. The XY plane, YZ plane, and ZX plane represent imaginary planes parallel to the X and Y directions, imaginary planes parallel to the Y and Z directions, and imaginary planes parallel to the Z and X directions, respectively.

[0017] The electronic device 200 is, for example, an information processing terminal such as a smartphone, a tablet computer, a notebook PC (Personal Computer), etc. Furthermore, the electronic device 200 is not limited to these, and may be, for example, a structure such as a pillar or a wall, digital signage, an electronic device including a display panel inside a train, or an electronic device including various display panels inside a vehicle.

[0018] 1 and 2, a display module D capable of performing a display function is disposed on the entire top surface or at least a part of the top surface of the electronic device 200. The transparent antenna 100 of the present invention is disposed above a touch panel 230 on a display panel 220. The transparent antenna 100 of the present invention is visible from outside the electronic device 200 through a transparent cover 240, and is transparent so that the display panel 220 can be seen from the outside through the transparent antenna 100.

[0019] Referring to FIG. 2, in the electronic device 200, the display panel 220, the touch panel 230, the transparent antenna 100, and the transparent cover 240 are collectively referred to as a display module D (also referred to as a display module).

[0020] In addition to the display module D, the electronic device 200 includes a housing 210, a wiring board 250, electronic components 260A, 260B, 260C, and 260D, a battery 270, and the like.

[0021] 1 and 2 show an example in which the electronic device 200 equipped with the transparent antenna 100 is a smartphone, but the electronic device equipped with the transparent antenna of the present invention may have other configurations as long as it includes a housing 210, a transparent cover 240, and a display panel 220. Furthermore, the electronic device 200 may not be equipped with a touch panel 230.

[0022] Housing 210 is, for example, a case made of metal and / or resin, and covers the bottom and side surfaces of electronic device 200. Housing 210 has opening edge 211 which is the upper end of the peripheral wall, and transparent cover 240 is attached to opening edge 211. Housing 210 has storage section 212 which is an internal space communicating with opening edge 211, and storage section 212 stores wiring board 250, electronic components 260A to 260D, battery 270, etc.

[0023] Transparent cover 240, which is an example of a cover glass, is a transparent glass plate provided on the top surface and has a size that matches open edge 211 of housing 210 in a plan view. In this example, transparent cover 240 is an example of a glass plate that is mostly flat and has both ends in the horizontal direction (+-X direction) that are gently curved downward, but it may also be a glass plate that is flat in the horizontal direction. Alternatively, transparent cover 240 may also have both ends that are gently curved downward in the vertical direction (Y direction) of electronic device 200. Here, a form in which transparent cover 240 is made of glass will be described, but transparent cover 240 may also be made of resin.

[0024] The transparent cover 240 is attached to the open end 211 of the housing 210, thereby sealing the storage section 212 of the housing 210.

[0025] The upper surface of the transparent cover 240 is an example of the outer surface of the transparent cover 240, and the lower surface of the transparent cover 240 is an example of the inner surface of the transparent cover 240. The transparent antenna 100 and the touch panel 230 are provided on the inner surface side of the transparent cover 240. Because the transparent cover 240 is transparent, the touch panel 230 and the display panel 220 provided inside can be seen through the transparent cover 240 from the outside of the electronic device 200.

[0026] Electronic components 260A to 260C are mounted on the wiring board 250. A power feed line extending from the power feed area 120 (see FIG. 5) of the transparent antenna is connected to the wiring board 250. The wiring board 250 and the power feed area 120 of the transparent antenna 100 may be connected using a connector, an ACF (Anisotropic Conductive Film), or the like, or may be connected using other components.

[0027] As an example, the electronic component 260A is a communication module that is connected to the power supply area 120 of the transparent antenna 100 via wiring on the wiring board 250 and processes signals transmitted or received via the transparent antenna 100. The central electronic component 260B is, for example, a camera.

[0028] As an example, electronic components 260C and 260D are components that perform information processing related to the operation of electronic device 200, and are realized by a computer that includes, for example, a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), an input / output interface, and an internal bus.

[0029] The battery 270 is a rechargeable secondary battery, and supplies the power required for the operation of the display module D, the electronic components 260A to 260D, and the like.

[0030] <Display module> Next, the position of the transparent antenna 100 in the display module D will be described. FIG.

[0031] Although not shown in Fig. 2, as shown in Fig. 3, the display module D has an inner adhesive layer 281, a polarizing plate 282, and an outer adhesive layer 283 between the touch panel 230 and the transparent cover 240. The inner adhesive layer 281 and the outer adhesive layer 283 are made of a transparent optical adhesive OCA (Optical Clear Adhesive).

[0032] The transparent antenna 100 of the present invention is provided either (1) between the touch panel 230 and the inner adhesive layer 281, (2) between the inner adhesive layer 281 and the polarizing plate 282, or (3) between the polarizing plate 282 and the outer adhesive layer 283, as shown by the arrows in Figure 3.

[0033] An adhesive layer may be provided between the touch panel 230 and the display panel 220. Alternatively, the touch panel 230 may be a "metallic thin wire layer for an on-cell touch panel" formed directly on the surface of the display panel 220 without providing an adhesive layer.

[0034] 2 and 3 show an example in which the touch panel 230 is provided in the display module D, but the touch panel 230 may not be mounted on the display module D mounted on the electronic device 200. When the touch panel 230 is not mounted, the transparent antenna 100 may be disposed between the display panel 220 and the inner adhesive layer 281 as the case (1).

[0035] The display panel 220 is, for example, a liquid crystal display panel, an organic EL (Electro-luminescence) or an OLED (Organic Light Emitting Diode) display panel. In either configuration, it is disposed at the bottom of the display module D.

[0036] In addition, since the transparent antenna 100 is provided partially in the display module D, the touch panel 230, the inner adhesive layer 281, the polarizing plate 282, and / or the outer adhesive layer 283 may be made thinner in the area where the transparent antenna 100 is provided than in other areas, or the inner adhesive layer 281, the polarizing plate 282, and / or the outer adhesive layer 283 may not be provided. This makes it possible to prevent the display module D from being raised only in the area of ​​the transparent antenna 100.

[0037] However, it has been found that if the transparent antenna 100 is too thick, problems arise, such as the edges of the transparent antenna being visible and air becoming more likely to become trapped at the boundary with the adhesive 283. The thickness of the transparent substrate 101 (see FIG. 5) of the transparent antenna 100 is preferably 300 μm or less, more preferably 150 μm or less, and particularly preferably 100 μm or less. Furthermore, from the viewpoint of ease of handling, the thickness of the transparent antenna 100 is preferably 10 μm or more, and more preferably 50 μm or more.

[0038] 1 and 2 show an example in which both ends of the display module D in the +Y direction are gently curved, but the display module D may have a flat shape with no curved ends. In that case, the transparent antenna 100 may also have a flat shape. Note that when the transparent antenna 100 has a partially curved surface, the power supply region, which will be described later, will have a curved shape.

[0039] <Examples of 5G frequency bands and operating bands of the transparent antenna of this invention> 4 is a diagram showing frequency bands allocated to the fifth generation mobile communication system (5G) in each country and examples of bands in which the transparent antenna of the present invention can operate. The transparent antenna 100 of the present invention can operate in two bands, f1 and f2, in the 5G band, i.e., it is set to resonate in two frequency bands.

[0040] As an example (band example 1) of the two frequency bands f1 and f2, frequency f1 is 24.2 to 29.5 GHz, and frequency f2 is 37.3 to 40 GHz. By setting these bands, it is possible to support the two 5G bands set in the United States, China, and Australia, as shown in Figure 4. In the following, the center frequency of frequency f1 is set to 28 GHz, and the center frequency of frequency f2 is set to 39 GHz.

[0041] In addition to the two frequency bands, a frequency f3 of 3.3 to 5.0 GHz may also be applicable. By setting this band, it is possible to support two 5G bands set in the United States, Canada, China, Australia, the EU, the United Kingdom, Germany, Italy, South Korea, and Japan, as well as three 5G bands set in the United States, China, and Australia, as shown in Fig. 4.

[0042] <First example of antenna configuration> Next, the configuration of a transparent antenna 100 according to a first configuration example of the present invention will be described with reference to Figs. 5 to 7. Fig. 5 is a perspective view of the transparent antenna 100 according to the first configuration example of the present invention. Fig. 6 is an explanatory diagram of the transparent antenna 100 according to the first configuration example, where (A) is a top view seen from the +Z direction and (B) is a bottom view seen from the -Z direction. Note that even when a portion of the transparent antenna 100 is arranged along a curve as in Fig. 1, Fig. 5 shows the transparent antenna 100 in a state parallel to the XY plane before it is bent.

[0043] The transparent antenna 100 has a transparent substrate 101, and an antenna pattern 110 and a feeding area 120 are provided on the transparent substrate 101. The antenna pattern 110 of this configuration is an example of a monopole antenna.

[0044] The transparent substrate (also referred to as a transparent base material) 101 is, for example, a flexible substrate made of polyimide, and can be bent in the Z direction and / or the X direction. The transparent substrate 101 is colorless and transparent.

[0045] Furthermore, the power supply area 120 is disposed at the longitudinal end (−Y direction end) of the transparent substrate 101, and is electrically connected to the first line element 111 of the antenna pattern 110. In this configuration example, the power supply area 120 is a planar power supply section on which a power supply wiring is formed, and is provided only on the upper surface side (+Z side) of the transparent substrate 101.

[0046] When the transparent antenna 100 is incorporated into the electronic device 200, the power supply area 120 is electrically connected to the wiring board 250 and the electronic component 260A, which is a communication circuit. In Fig. 5, as an example, the power supply area 120 is shown as being configured to occupy approximately half of the area from the end on the -Y direction side. Note that the range of the power supply area 120 may also be approximately 1 / 4 to 3 / 4 on the -Y direction side.

[0047] 5 illustrates an example in which the end of the power supply area 120 extends to the end (-Y side end) of the transparent substrate 101, but part or all of the power supply area 120 may be located outside the periphery of the substrate 101. Furthermore, by forming the power supply area 120 to be flexible, the power supply area 120 may be configured to wrap around the side edge or back surface of the display module D and be electrically connected on the side or back surface.

[0048] The antenna pattern 110 of this configuration has a first line element 111, a second line element 112, and a third line element 113. In this configuration, all of the elements 111 to 113 are provided on the +Z side, which is the upper surface side of the transparent substrate 101.

[0049] Specifically, one end of the first line element 111 is a feed point F that connects to the feed area 120, and extends in a first direction (+Y direction) that is the transmission direction from the feed point F. The other end of the first line element 111 is a free end.

[0050] The second line element 112 branches off from the vicinity of the feed point F of the first line element 111 and extends in a second direction (+X direction) perpendicular to the first direction.

[0051] The third line element 113 is bent from the other end of the second line element 112 and extends in the first direction (+Y direction) substantially parallel to the first line element 111. The other end of the third line element 113 is a free end, and the third line element 113 is shorter than the first line element 111.

[0052] Here, the conductor length of the first line element 111 is L111, and the wavelength on the transparent substrate 101 at the resonant frequency f1 (28 GHz) of the transparent antenna 100 is λ 01 As a result, L111 is approximately 0.25λ 01 Therefore, when it is desired to improve the antenna gain in the frequency band f1, the conductor length L111 of the first line element 111 may be adjusted to within ±10% of approximately 2.1 mm, for example.

[0053] On the other hand, the conductor length of the third line element 113 is L113, and the wavelength on the transparent substrate 101 at the resonant frequency f2 (39 GHz) of the transparent antenna 100 is λ 02 As a result, L113 is approximately 0.25λ 02 Therefore, when it is desired to improve the antenna gain in frequency band f2, the conductor length L113 of the third line element 113 may be adjusted to within ±10% of approximately 1.325 mm, for example.

[0054] <Transparent conductor for transparent antenna> Fig. 7 is an explanatory diagram of the transparent conductor 30 of the transparent antenna 100 of the present invention. The transparent conductor 30 is formed on the surface of a transparent substrate 101, and is used, for example, to constitute the antenna pattern 110 and the planar power supply portion of the power supply area 120 shown in Figs. 6 and 7. The transparent conductor 30 is a conductor with such high optical transparency that it is difficult to see with human eyesight.

[0055] Specifically, the transparent conductor 30 is a layer of conductive lines, i.e., a thin metal wire layer, formed, for example, in a mesh shape to enhance light transmittance. As shown in Fig. 7, in the mesh-shaped thin metal wire layer, a plurality of thin metal wires 31 extending in one direction and a plurality of thin metal wires 32 extending in the other direction are arranged to intersect with each other, and openings (through holes) 33, which are mesh-like gaps (openings), are formed.

[0056] When the transparent conductor 30 is formed in a mesh shape, the openings 33 of the mesh may be rectangular or rhombic. When the openings 33 of the mesh are formed in a rectangular shape, the mesh preferably has square openings, which improves design. The openings 33 of the mesh may also have a random shape formed by a self-assembly method, which can suppress moire. The line widths w31 and w32 of the fine metal wires 31 and 32 constituting the mesh are preferably 1 to 10 μm, more preferably 1 to 5 μm, and even more preferably 1 to 3 μm. The line spacings (also called openings or pitches) p31 and p32 between the fine metal wires 31 and between the fine metal wires 32 of the mesh are preferably 300 to 500 μm.

[0057] The aperture ratio, which is the ratio of the area of ​​the openings 33 to the entire mesh in the transparent conductor 30, is preferably 80% or more, and more preferably 90% or more. The greater the aperture ratio of the transparent conductor 30, the higher the visible light transmittance of the transparent conductor 30 can be.

[0058] When the transparent conductor 30 is formed in a mesh shape, the thickness of the transparent conductor 30 may be 1 to 40 μm. By forming the transparent conductor 30 in a mesh shape, it is possible to increase the visible light transmittance even if the transparent conductor 30 is thick. The thickness of the transparent conductor 30 is more preferably 5 μm or more, and even more preferably 8 μm or more. Furthermore, the thickness of the transparent conductor 30 is more preferably 30 μm or less, even more preferably 20 μm or less, and particularly preferably 15 μm or less.

[0059] In the transparent conductor 30, the conductor thickness t is set smaller than the line widths (conductor widths) w31 and w32 of the mesh-like thin lines. This is because an aspect ratio exceeding 1 results in structural imbalance, making the structure more fragile and difficult to manufacture. However, since a thicker conductor thickness t can reduce the sheet resistance value, a larger conductor thickness t is better for antenna efficiency, so it is preferable that t be smaller than w and as large as possible.

[0060] The conductive material of the thin metal wires 31 and 32 of the transparent conductor 30 can be copper, but other metal materials such as gold, silver, platinum, aluminum, chromium, tin, iron, and nickel can also be used, and the material is not limited to these.

[0061] The antenna pattern 110 and the power supply area 120 realized by such a transparent conductor 30 are transparent, have high optical transparency so that they are difficult to see with human eyesight, and can function as conductors. The transparent antenna 100 of the first configuration example formed in this way does not have a ground layer on the back side, as shown in Figure 6(B), so the thickness of the transparent antenna 100 can be made thin.

[0062] When a transparent antenna without a ground plane is installed in a mobile device such as a smartphone, which requires miniaturization, the touch panel or display is placed closer to the antenna pattern than if the antenna had a ground plane. However, because the conductive materials in the touch panel or display have finite resistivities, our research has revealed that in a transparent antenna configuration without a ground plane on the back side, a conductor with a certain resistance placed nearby can affect the electromagnetic field distribution near the antenna, potentially degrading the antenna characteristics. We also found that when the materials used to construct the display or touch panel placed underneath are different, the antenna characteristics can change depending on the surface resistance of the material (effective surface resistance at the antenna operating frequency, also known as sheet resistance).

[0063] Therefore, there is a demand for an antenna design that can operate stably even when conductors with various surface resistance values ​​are placed in close proximity to the antenna.

[0064] <Simulation example 1> Therefore, in order to confirm the influence of nearby conductors, the inventors of the present application performed various simulation measurements on a pseudo display module PD in which a transparent cover 240 and a resistive metal conductor M are provided above and below the transparent antenna 100 of the present invention as shown in Figure 5.

[0065] 8 is a diagram showing a pseudo display module PD in which the transparent antenna 100 of the first configuration example of the present invention is sandwiched between a transparent cover 240 and a metal conductor M having a predetermined resistance, simulating a display module. More specifically, a metal conductor M with a sheet resistivity of 1 Ω / sq (ohms per square, sometimes written as Ω / □) is arranged at the bottom of the pseudo display module PD, which serves as a resistor simulating a display or touch panel. An inner adhesive layer 281 is arranged on top of the metal conductive layer M.

[0066] 3(2), the transparent antenna 100 was provided between the inner adhesive layer 281 and the polarizing plate 282. Then, the outer adhesive layer 283 and the transparent cover 240 were placed on the transparent antenna 100.

[0067] The S11 parameter characteristic value and directivity measured using the transparent antenna 100 alone in FIG. 5 and the pseudo display module PD sandwiching the transparent antenna in FIG. 8 will be described below.

[0068] When the S11 parameter and directivity were measured, the dimensions of each part of the transparent antenna 100 alone of the first configuration example shown in FIGS. 5 and 6 and the transparent antenna 1 of the pseudo display module PD shown in FIG. 8 were as follows, in mm: L111:20.5 L112:0.2 L113:1.4 W11:0.2 X101:6 Y101:7.5 is.

[0069] Furthermore, the dimensions of the transparent conductor 30 that constitutes the antenna pattern 110 and the power supply area 120 are, in μm units, as follows: Conductor thickness of transparent conductor 30: 1 Conductor width w31, w32:4 Line spacing p31,p32:120 is.

[0070] The thickness of each part of the layer shown in FIG. 8 is expressed in μm as follows: Thickness of transparent cover 240: 500 Thickness of outer adhesive layer 283: 150 Thickness of polarizing plate 282: 150 Thickness of transparent conductor 30 (110, 120): 1 Thickness of transparent substrate 101: 75 Thickness of inner adhesive layer 281: 150 is. In particular, the thickness of the transparent substrate 101 is 75 μm. Since the surface impedance for setting the surface resistance is set as the boundary condition, the metal conductor M is set to have no thickness.

[0071] Figure 9 shows the S11 parameter when the resistance value of the metal conductor M simulating the lower display is changed in the pseudo display module PD sandwiching the transparent antenna of Figure 8. In this measurement, the S11 parameter was obtained for each of the cases where the sheet resistance value of the lower metal conductor M was 0.1 Ω / sq, 1 Ω / sq, and 10 Ω / sq in a co-electromagnetic field simulation in which the resonant frequency of the transparent antenna 100 shown in Figures 5 and 8 was set to 28 GHz and 39 GHz.

[0072] As shown in Fig. 9, regardless of whether the metal conductor M has a sheet resistance value of 0.1 Ω / sq, 1 Ω / sq, or 10 Ω / sq, the S11 parameter has two peaks, and good values of -3 dB or less are obtained around 28 GHz and around 39 GHz. At the peaks of the S11 parameter, it is more preferable that the value is -4 dB or less, and particularly preferable that the value is -5 dB or less.

[0073] In other words, when the input reflection coefficient S11 at a frequency of f [GHz] is written as S11(ρ,f), at two frequencies f1(28 GHz) and f2(39 GHz) between 2 GHz < f < 50 GHz, S11(0.1 [Ω / sq], 28 [GHz]) < -3 [dB] and S11(0.1 [Ω / sq], 39 [GHz]) < -3 [dB], S11(1 [Ω / sq], 28 [GHz]) < -3 [dB] and S11(1 [Ω / sq], 39 [GHz]) < -3 [dB], and it can be said that S11(10 [Ω / sq], 28 [GHz]) < -3 [dB] and S11(10 [Ω / sq], 39 [GHz]) < -3 [dB].

[0074] That is, by adopting the antenna design of the transparent antenna 100 as shown in Fig. 5, as shown by the two thick arrows in Fig. 9, at 28 GHz and 39 GHz, even if the sheet resistance value of the adjacent conductor fluctuates, the antenna characteristics are less likely to fluctuate.

[0075] Taking apart an example of an electronic device and measuring the resistance values of a touch panel and a display that form the on-cell metal fine wire layer, it was calculated to be 0.1 Ω / sq to 200 Ω / sq depending on the location and type. In the present invention, as the sheet resistance value of the touch panel, 0.1 Ω / sq to 10 Ω / sq etc. was used as the design guideline. Here, “on-cell” refers to a structure in which an electrode layer is directly formed on the surface of the display panel 220, rather than attaching a touch panel formed on a substrate independent of the display panel 220.

[0076] As shown in FIG. 9, the transparent antenna 100 of the present invention can operate relatively stably as an antenna in two bands, around 28 GHz and around 39 GHz, even when placed on any type of display or touch panel with a sheet resistance value of 0.1 Ω / sq to 10 Ω / sq. In other words, it can achieve dual band operation in two frequency bands in the 5G band.

[0077] <Second example of antenna configuration> Next, a transparent antenna 100A according to a second configuration example of the present invention will be described with reference to FIGS.

[0078] Fig. 10 is a perspective view of a transparent antenna according to a second configuration example of the present invention. Fig. 11 is an explanatory diagram of a transparent antenna 100A according to the second configuration example, where (A) is a top view seen from the +Z direction and (B) is a bottom view seen from the -Z direction. Note that even when the transparent antenna is arranged along a curve as in Fig. 1, Fig. 10 shows the transparent antenna in a state parallel to the XY plane before being folded.

[0079] The transparent antenna 100A of this configuration example has a transparent substrate 102, on which a feeding area 160 consisting of an antenna pattern 140, directors 150 (151, 152), and a microstrip line is provided. The +Y side end of the boundary where the feeding area 160 on the lower surface ends becomes a reflector 163. The antenna pattern 140 of the transparent antenna 100A is a Yagi-Uda antenna.

[0080] In this configuration example, the microstrip line that forms the power supply area 160 is a power supply line having a transmission line 161 on the upper surface side and a ground layer 162 on the lower surface side. The transmission line 161 is provided on the surface on the +Z direction side of the substrate 102, and is connected to the power supply point FDa of the first line element 141.

[0081] The ground layer 162 is provided on the surface on the −Z direction side of the substrate 102 so as to overlap the transmission line 161 in plan view. The center of the end side on the +Y direction side of the ground layer 162 is connected to the feed point FDb of the fifth line element 145.

[0082] The antenna pattern 140 in this configuration has a first line element 141, a second line element 142, a third line element 143, and a fourth line element 144 on the upper surface side.

[0083] On the upper surface side, the first line element 141 continues from a feed point FDa connected to the transmission line 161, has approximately the same thickness as the transmission line 161, and extends in a first direction (+Y direction) that is the transmission direction. The second line element 142 bends from the tip of the first line element 141 and extends in a second direction (-X direction) perpendicular to the first direction. The other end of the second line element 142 is a free end.

[0084] The third line element 143 branches off from the periphery of the connection between the second line element 142 and the first line element 141, and extends approximately parallel to the first line element 141 in a direction approaching the power supply area 160. The fourth line element 144 bends from the other end of the third line element 143, and extends in the second direction (-X direction) approximately parallel to the second line element 142. The other end of the fourth line element 144 is a free end, and the fourth line element 144 is shorter than the second line element 142.

[0085] Furthermore, the antenna pattern 140 has a fifth line element 145, a sixth line element 146, a seventh line element 147, and an eighth line element 148 on the lower surface side.

[0086] On the lower surface side, the fifth line element 145 extends in a first direction (+Y direction), which is the transmission direction, from a feed point FDb connected to the ground layer 162 of the feed area 160. The sixth line element 146 bends from the tip of the fifth line element 145 and extends in a second direction (+X direction) perpendicular to the first direction. The other end of the sixth line element 146 is a free end. As shown in FIG. 11 , the extension direction of the sixth line element 146 is opposite to the extension direction of the second line element 142.

[0087] The seventh line element 147 branches off from the periphery of the connection between the sixth line element 146 and the fifth line element 145, and extends approximately parallel to the fifth line element 145 in a direction approaching the power supply area 160. The eighth line element 148 bends from the other end of the seventh line element 147, and extends in the second direction (+X direction) approximately parallel to the sixth line element 146. The other end of the eighth line element 148 is a free end, and the eighth line element 148 is shorter than the sixth line element 146.

[0088] As shown in FIGS. 10 and 11, the antenna elements 141 to 148 on the upper surface (front surface side) and the antenna elements 145 to 148 on the lower surface (rear surface side) are symmetrical with respect to the antenna elements 141 and 145 that overlap in the vertical direction.

[0089] Here, the conductor length of the second line element 142 is L142, and the wavelength on the transparent substrate 102 at the resonant frequency f1 (28 GHz) of the transparent antenna 100A is λ 01 As a result, L142 is approximately 0.25λ 01 The conductor length L142 of the second line element 142 is set to an odd multiple of . Therefore, if it is desired to improve the antenna gain in the frequency band f1, it is advisable to adjust the conductor length L142 of the second line element 142, for example, to within ±10% of approximately 2.1 mm. The length of the sixth line element 146 on the lower surface side is set to be equal to the length of the second line element 142. The second line element 142 and the sixth line element 146 form a radiator at a frequency of 28 GHz.

[0090] The conductor length of the fourth line element 144 is L144, and the wavelength on the transparent substrate 102 at the resonant frequency f2 (39 GHz) of the transparent antenna 100A is λ 02 As a result, L144 is approximately 0.25λ 02 The conductor length L144 of the fourth line element 144 is set to an odd multiple of 1.2 mm. Therefore, if it is desired to improve the antenna gain in frequency band f2, it is advisable to adjust the conductor length L144 of the fourth line element 144, for example, to within ±10% of approximately 1.2 mm. The length of the eighth line element 148 on the underside is set to be equal to the length of the fourth line element 144. The fourth line element 144 and the eighth line element 148 form a radiator at a frequency of 39 GHz. The slight difference in the numerical value for 39 GHz from that of the monopole is the result of fine adjustments due to the slightly different bending method.

[0091] On the top surface side, the director 151 extends in the second direction, being spaced a distance D1 in the +Y direction from the second line element 142. The director 151 is longer than the second line element 142 and extends beyond the position of the first line element 141 on the +X side. The director 151 serves as a director at a frequency of 28 GHz, and the distance D1 is approximately 0.25λ at a frequency of 28 GHz. 01 The length of director 151 is set to an odd multiple of 0.5λ, which is the sum of the lengths of second line element 142 and sixth line element 146, which are radiators of 28 GHz. 01 This ensures capacitance by setting the length slightly shorter than the

[0092] On the lower surface side, the director 152 extends in the second direction, spaced a distance D2 in the +Y direction from the sixth line element 146. The director 152 is longer than the sixth line element 146 and extends on the -X side beyond the position of the fifth line element 145. The director 152 serves as a director at a frequency of 39 GHz, and the distance D2 is approximately 0.25λ at a frequency of 39 GHz. 02The length of the director 152 is set to be an odd multiple of 0.5λ, which is the sum of the lengths of the fourth line element 144 and the eighth line element 148, which are radiators for 39 GHz. 02 This ensures capacitance by setting the length slightly shorter than the

[0093] Furthermore, reflector 163, which is the boundary (gap) at the +Y side end of ground layer 162, is a reflector common to 28 GHz and 39 GHz, and is longer than the antenna elements (142 and 146 combined, approximately half the wavelength) and (144 and 148 combined, approximately half the wavelength), which are radiators.

[0094] The Yagi-Uda antenna of this configuration can be expected to have four resonant frequencies because it has directors 151 and 152 in addition to the antenna pattern 140 formed on the front and back surfaces. Therefore, the transparent antenna 100A of this configuration can be made into a triple-band (multi-band) antenna that resonates with frequency bands f1 and f2 as well as frequency band f3, which is 3.3 to 5.0 GHz, as shown in band example 2 of Fig. 4.

[0095] In addition, in this configuration example, the antenna pattern 140, the director 150, the transmission path 161 of the power supply area 160 consisting of a microstrip line, and the ground layer 162 are realized by the mesh-shaped transparent conductor 30 shown in Figure 6.

[0096] In this configuration example, unlike the first configuration example, layers are also formed on the bottom side, but the antenna elements 145 to 148, the director 152, and the ground layer 162 of the power supply area 160 on the bottom side can be formed very thinly using the transparent conductor 30.

[0097] Here, the thickness of the transparent conductor 30, which is made up of a thin metal wire layer, is thinner than the ground substrate of, for example, a patch antenna. Therefore, the overall thickness of the transparent antenna 100A in this configuration example can be thinner than that of a patch antenna because it does not have a ground substrate for the antenna pattern of a patch antenna, which requires a certain thickness. For example, in electronic devices, the allowable thickness for transparent antennas is highly restricted, being 100 μm or less, and even if the patch antenna cannot be contained within that thickness due to the combined thickness of the transparent substrate and the ground substrate, the transparent antennas in the first and second configuration examples described above are thin and can therefore be contained within the thickness restriction.

[0098] Although the first configuration example shows an example in which the feed area 120 is a planar feed section provided only on the front side, and the second configuration example shows an example in which the feed area 160 is a microstrip line provided on both the front and back sides, the configuration of the feed area may be reversed. More specifically, a planar feed section such as that shown in Fig. 5 may be applied to the feed area of ​​the Yagi-Uda antenna shown in Fig. 11, and conversely, a microstrip line such as that shown in Fig. 11 may be applied to the feed area of ​​the monopole antenna shown in Fig. 5.

[0099] <Comparative Example> Here, a transparent antenna 900 according to a comparative example will be described with reference to Figures 12 and 13. Figure 12 is a perspective view of the transparent antenna 900 according to the comparative example, and Figure 13 is an explanatory diagram of the transparent antenna 900 according to the comparative example, where (A) is a top view seen from the +Z direction and (B) is a bottom view seen from the -Z direction.

[0100] The transparent antenna 900 of this configuration example has a substrate 901, on which an antenna pattern 910 and a power supply area 920 are provided. In this configuration, the power supply area 920 is formed of a microstrip line. The antenna pattern 910 of the transparent antenna 900 is a patch antenna.

[0101] Ground layers 931 and 932 are provided on the surface of the substrate 901 that does not have the antenna pattern 910. The ground layers 931 and 932 are provided so as to overlap the antenna pattern 910 and the transmission line 921 in a plan view.

[0102] The power supply area 920 in this comparative example is a power supply line formed by a microstrip line and having a transmission line 921 on the upper surface and a power supply ground layer 932 on the lower surface. The transmission line 921 is provided on the surface on the +Z direction side of the substrate 901, and is connected to a power supply point FDx located approximately in the center of the edge of the central planar patch element 911.

[0103] The entire lower surface side of substrate 901 is a ground layer, with antenna ground layer 931 on the +Y side and power feeding ground layer 932 on the -Y side. Power feeding ground layer 932 is provided on the surface on the -Z direction side of substrate 901, overlapping transmission line 921 in plan view.

[0104] Antenna pattern 910 has a central planar patch element 911 and extensions 912, 913 that extend out from the +Y side edge of the central planar patch element to the +Y side. Grooves 914, 915 are formed at the boundary between the +Y side end of central planar patch element 911 and extensions 912, 913. In a patch antenna, dual bands are achieved by making the patch-shaped antenna pattern E-shaped, so this shape is used. However, the E-shape is merely one example of how dual bands can be achieved.

[0105] In this comparative example, the antenna pattern 910, transmission path 921, antenna ground layer 931, and power supply ground layer 932 formed on the upper surface of the substrate 901 are realized by the mesh-shaped transparent conductor 30 shown in Figure 6.

[0106] As will be described later, in the case of a patch antenna, it has been found that the operating characteristics of the antenna deteriorate when the antenna ground layer 931 and the antenna layer 910 formed by the antenna pattern 910 come close to each other. This deterioration is particularly noticeable when supporting two or more frequencies, making it difficult to set the same radiation efficiency at two or more frequencies.

[0107] <Simulation example 2> The inventors of the present application simulated the S11 parameter, which is the input reflection coefficient, and the radiation efficiency Eff for the transparent antennas of the first configuration example, the second configuration example, and the comparative example. Fig. 14 is a diagram showing the S11 parameter and the radiation efficiency Eff for the transparent antennas of the first configuration example, the second configuration example, and the comparative example of the present invention.

[0108] When this measurement was performed, the antenna alone of the first configuration example shown in Fig. 5 and the pseudo display module PD shown in Fig. 8 had the same dimensions as those described above. When the dimensions of each part of the transparent antenna 100A alone of the second configuration example shown in Fig. 10 are expressed in mm, L141:2.1 L142:2.1 L143:0.2 L144:1.21 L145:2.1 L146:2.1 L147:0.2 L148:1.21 L151:3.48 L152:2.38 D1:1.6 D2:1.4 W14, W15: 0.18 X102:9 Y102:9.5 is.

[0109] 8, the second configuration example differs in that, in addition to the above dimensions, a microstrip antenna ground layer 162 made of a 1 μm thin metal wire layer is formed on the back side of the transparent substrate 102. In particular, the thickness of the transparent base material 102 is 75 μm, the same as in the first configuration example.

[0110] Furthermore, the dimensions of each part of the transparent antenna 900 according to the comparative example shown in FIG. 12 are expressed in mm as follows: L911:25 L912:25 L921:0.15 X901:10 Y901:10 is.

[0111] Furthermore, regarding the thickness, if the unit is μm, Thickness of transparent cover 240: 500 Thickness of outer adhesive layer 283: 150 Thickness of polarizing plate 282: 150 Thickness of transparent conductor 30 (910, 921): 1 Thickness of transparent substrate 901: 75 Thickness of transparent conductor 30 (931, 932): 1 Thickness of inner adhesive layer 281: 150 is. In particular, the thickness of the transparent substrate 901 is 75 μm.

[0112] In FIG. 14, the difference in radiation efficiency represents {Eff(ρ, 28 GHz) - Eff(ρ, 39 GHz)}. That is, if it is a positive value, Eff(ρ, 28 GHz) > Eff(ρ, 39 GHz). In the transparent antenna 900, which is a patch antenna, in the pseudo display module state, the difference in Eff is as large as 33% in the two frequency bands of 28 GHz and 39 GHz. In addition, the S11 parameter also has a relatively large value at one of the frequencies. Therefore, it is considered difficult for the transparent antenna 900 according to the comparative example to operate stably as an antenna at both frequencies in response to dual bands.

[0113] In contrast, in the pseudo display module of the transparent antennas 100 and 100A of the present invention, even if the surface resistivity ρ of the metal conductor is changed in the two frequency bands of 28 GHz and 39 GHz, the differences in radiation efficiency Eff are 18%, 14%, 17%, 13%, and 4%, respectively, all within 20%. As a result, the transparent antennas 100 and 100A of the present invention can operate as antennas in two bands, around 28 GHz and around 39 GHz, i.e., they can achieve dual band operation in two frequency bands in the 5G band.

[0114] Thus, in order to realize dual band operation in the 5G band, it is preferable that the difference in radiation efficiency Eff between the two frequency bands of 28 GHz and 539 GHz be less than 25%, and more preferably less than 20%.

[0115] As shown in FIG. 14, in the pseudo display module using the transparent antenna 100 of FIG. 5, S11(0.1[Ω / sq],28[GHz])<-3[dB] S11(0.1[Ω / sq],39[GHz])<-3[dB] S11(10[Ω / sq],28[GHz])<-3[dB] S11(10[Ω / sq],39[GHz])<-3[dB] And, |Eff(0.1[Ω / sq],28[GHz])-Eff(0.1[Ω / sq],39[GHz])|<25%, It can also be seen that |Eff(10[Ω / sq],28[GHz])-Eff(10[Ω / sq],39[GHz])|<25%.

[0116] Also, S11(0.1[Ω / sq],29[GHz]) <S11(0.1[Ω / sq],38[GHz])であるが、 S11(10[Ω / sq], 29[GHz])>S11(10[Ω / sq], 38[GHz]), The magnitude of S11 at the two frequencies is reversed due to the sheet resistance of the adjacent conductor. This design reduces the degradation of characteristics due to bias toward one of the two frequencies over a wide range of sheet resistance, making stable operation possible, which is even more preferable. In such cases, keeping the magnitude of Eff constant will result in even more stable operation, which is particularly preferable.

[0117] Similarly, in the pseudo module using the transparent antenna 100A of FIG. S11(0.1[Ω / sq],28[GHz])<-3[dB] S11(0.1[Ω / sq],39[GHz])<-3[dB] S11(10[Ω / sq],28[GHz])<-3[dB] S11(10[Ω / sq],39[GHz])<-3[dB] And, |Eff(0.1[Ω / sq],28[GHz])-Eff(0.1[Ω / sq],39[GHz])|<25%, It can also be seen that |Eff(10[Ω / sq],28[GHz])-Eff(10[Ω / sq],39[GHz])|<25%.

[0118] Also, Eff(0.1[Ω / sq],29[GHz])>Eff(0.1[Ω / sq],38[GHz]), Eff(10[Ω / sq],29[GHz]) <Eff(10[Ω / sq],38[GHz])であって、 The magnitude of Eff is reversed at the two frequencies. By designing in this way, it is possible to reduce the deterioration of characteristics due to bias towards one of the two frequencies over a wide range of sheet resistance, and it is possible to achieve balanced and stable operation, which is even more preferable. In such cases, it is particularly preferable to keep the magnitude of S11 constant, as this will result in even more stable operation.

[0119] In this way, in the present invention, by setting the behavior of the values ​​of S11 and radiation efficiency Eff relative to the sheet resistance value at two frequencies, particularly stable antenna characteristics can be obtained.

[0120] For example, by being able to support dual bands in electronic devices, it is possible to switch frequency bands when one line is congested or the radio wave conditions are poor. In the present invention, the transparent antenna can operate in two frequency bands, so it is possible to switch between the two frequency bands with just one antenna.

[0121] Although the first configuration example has been described as a monopole antenna and the second configuration example as a Yagi-Uda antenna, the antenna pattern of the present invention may be a dipole antenna, a Vivaldi antenna, or a log-periodic antenna. Even in the case of a dipole antenna, a Vivaldi antenna, or a log-periodic antenna, applying the above-described design for S11 and Eff will achieve the same effect.

[0122] In the case of a dipole antenna, this can be particularly easily realized by using an antenna pattern configuration in which directors 151 and 152 are removed from the Yagi-Uda antenna shown in FIG.

[0123] (Third configuration example) 15 is a diagram showing a transparent antenna 100B according to a third configuration example of the present invention. The transparent antenna 100B of this configuration example has a transparent substrate 103, on which an antenna pattern 110M1 and a feeding region 120M1 formed of a microstrip line are provided. The antenna pattern 110M1 of the transparent antenna 100B is a Vivaldi antenna.

[0124] Similar to the second configuration example, the power feeding area 120M1 in this configuration example is a microstrip line, a power feeding line having an upper-side transmission line 121M1 and a lower-side ground layer 122M1. The transmission line 121M1 is provided linearly on the surface on the +Z direction side of the transparent substrate 103 and is connected to the upper-side element 111M1. The ground layer 122M1 is provided planarly on the surface on the -Z side of the transparent substrate 103, with the +Y side edge curved so that the center is pointed toward the +Y side and connected to the lower-side element 112M1.

[0125] The antenna pattern 110M1 has an upper element 111M1 and a lower element 112M1. The upper element 111M1 is linearly connected to the transmission line 121M1 in the power feeding area 120M1 and gradually widens, extending to the corners of the transparent substrate 103 in the +Y and +X directions. The lower element 112M1 is connected to the center of the ground layer 122M1 in the power feeding area 120M1 and gradually widens, extending to the corners of the transparent substrate 103 in the +Y and -X directions.

[0126] The power supply area 120M1 and the antenna pattern 110M1 in FIG. 15 are made up of a transparent conductor 30, which is a lattice-shaped thin metal wire layer as shown in FIG.

[0127] In this configuration example, if the above-described design is applied to S11 and Eff, the same effect can be achieved.

[0128] Furthermore, although a single transparent antenna of the present invention can achieve dual bands, in order to further improve characteristics, a plurality of transparent antennas may be arranged in an array (antenna array).

[0129] Although the transparent antenna of an exemplary embodiment of the present invention has been described above, the present invention is not limited to the specifically disclosed embodiment, and various modifications and alterations are possible without departing from the scope of the claims.

[0130] This international application claims priority based on Japanese Patent Application No. 2020-078662, filed on April 27, 2020, the entire contents of which are incorporated herein by reference. [Explanation of symbols]

[0131] 30 Transparent conductor 31 Fine metal wire 32 Fine metal wire 33 Opening 100, 100A, 100B transparent antenna 101 Transparent substrate (transparent base material) 102 Transparent substrate (transparent base material) 103 Transparent substrate (transparent base material) 110,110M1 Antenna pattern (transparent conductor, thin metal wire layer) 111 First linear element 112 Second Linear Element 113 Third Linear Element 114 Fourth Linear Element 111M1 Upper element 112M1 Lower element 120 Power supply area (surface power supply, metal thin wire layer) 120M1 power supply area 121M1 transmission line 122M1 Ground plane 140 Antenna Pattern 141 First Linear Element 142 Second Linear Element 143 Third Linear Element 144 Fourth Linear Element 145 Fifth Linear Element 146 Sixth Linear Element 147 Seventh Linear Element 148 Eighth Linear Element 151 Top side waveguide 152 Bottom side waveguide 160 Power supply area (microstrip line) 161 Transmission Line 162 Ground Layer 200 Electronic equipment 210 cabinet 220 Display Panel 230 Touch Panel 240 Transparent cover (cover glass) 250 wiring board 260A, 260B, 260C, 260D Electronic Components 270 Battery D Display Module PD pseudo display module M Metal conductor

Claims

1. A transparent antenna comprising a transparent substrate and a metal fine wire layer on the upper side of the transparent substrate, wherein the transparent substrate has a thickness of 300 μm or less, the metal fine wire layer has an aperture ratio of 80% or more, when a metal conductor with a surface resistivity ρ [Ω / sq] is placed parallel to the antenna with a separation of 0.15 mm, and the input reflection coefficient S11 at a frequency of f [GHz] is written as S11(ρ,f), and the radiation efficiency is written as Eff(ρ,f) [%], at two frequencies f1 and f2 between 2 GHz < f < 50 GHz, S11(0.1 [Ω / sq], f1 [GHz]) < -3 [dB] S11(0.1 [Ω / sq], f2 [GHz]) < -3 [dB] |Eff(0.1 [Ω / sq], f1 [GHz]) - Eff(0.1 [Ω / sq], f2 [GHz])| < 25%, a transparent antenna.

2. S11(10 [Ω / sq], f1 [GHz]) < -3 dB S11(10 [Ω / sq], f2 [GHz]) < -3 dB, |Eff(10 [Ω / sq], f1 [GHz]) - Eff(10 [Ω / sq], f2 [GHz])| < 25%, the transparent antenna according to Claim 1.

3. the sign of S11(0.1 [Ω / sq], f1 [GHz]) - S11(0.1 [Ω / sq], f2 [GHz]) and the sign of S11(10 [Ω / sq], f1 [GHz]) - S11(10 [Ω / sq], f2 [GHz]) are different, the transparent antenna according to Claim 1 or 2.

4. the sign of Eff(0.1 [Ω / sq], f1 [GHz]) - Eff(0.1 [Ω / sq], f2 [GHz]) and the sign of Eff(10 [Ω / sq], f1 [GHz]) - Eff(10 [Ω / sq], f2 [GHz]) are different, the transparent antenna according to Claim 1 or 2.

5. |Eff(0.1 [Ω / sq], 28 [GHz]) - Eff(0.1 [Ω / sq], 39 [GHz])| < 25%, and |Eff(10 [Ω / sq], 28 [GHz]) - Eff(10 [Ω / sq], 39 [GHz])| < 25% the transparent antenna according to any one of Claims 1 to 4.

6. the transparent antenna has an antenna pattern and a feeding area formed by the metal fine wire layer, the antenna pattern is a type of antenna having no background on the lower surface side the transparent antenna according to any one of Claims 1 to 5.

7. The antenna pattern is a monopole antenna, a Yagi-Uda antenna, a dipole antenna, a Vivaldi antenna, or a log-periodic antenna. The transparent antenna according to claim 6.

8. The antenna pattern is a monopole antenna, The antenna pattern is a first strip element extending in a first direction, which is a transmission direction, from a feeding point connected to the feeding region; a second strip element branching from around a connection portion of the first strip element with the feeding region and extending in a second direction orthogonal to the first direction; and a third strip element bent from the other end of the second strip element and extending in the first direction substantially parallel to the first strip element. The transparent antenna according to claim 7.

9. The antenna pattern is a Yagi-Uda antenna The antenna pattern is a first strip element extending in a first direction, which is a transmission direction, from a feeding point connected to the feeding region; a second strip element bent from the tip of the first strip element and extending in a second direction orthogonal to the first direction; a third strip element branching from around a coupling portion of the second strip element with the first strip element and extending substantially parallel to the first strip element; and a fourth strip element bent from the other end of the third strip element and extending in the second direction substantially parallel to the second strip element, a waveguide spaced apart from the second strip element and extending in the second direction, and an end edge at the leading end in the transmission direction of the feeding region functioning as a reflector. The transparent antenna according to claim 7.

10. The frequency f1 is 24.2 to 29.5 GHz, and the frequency f2 is 37.3 to 40 GHz. The transparent antenna according to any one of claims 1 to 9.

11. When the input reflection coefficient S11 at a frequency of f [GHz] is written as S11(ρ,f), at a third frequency f3 between 2 GHz < f < 50 GHz, S11(0.1 [Ω / sq], f3 [GHz]) < -3 [dB] S11(10 [Ω / sq], f3 [GHz]) < -3 [dB], and f3 is 3.3 to 5.0 GHz. The transparent antenna according to any one of claims 1 to 10.

12. Having directivity in a direction perpendicular to the antenna plane when a metal conductor is placed below. A transparent antenna according to any one of claims 1 to 11.

13. A plurality of transparent antennas according to any one of claims 1 to 12 are arranged in a row. Antenna array.

14. A transparent antenna according to any one of claims 1 to 12; A display and A cover glass, The transparent antenna is disposed below the cover glass and above the display. Display module.

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