Glass plate with EBG structure and vehicle antenna device

Abstract

This EBG structure-attached glass plate comprises: a vehicle roof glass to be attached to a metal frame of a vehicle body; an EBG structure disposed on a first main surface of the roof glass, having a predetermined conductor pattern disposed periodically thereon, and formed in a frame shape; and a radio wave transmission / reception region surrounded by the EBG structure. When an antenna transmits or receives radio waves in the radio wave transmission / reception region, propagation of radio waves on the roof glass surface is suppressed.

Description

Technical Field

[0001] The present invention relates to a glass plate with an EBG structure and an antenna device for a vehicle.

Background Art

[0002] In recent years, various antennas have been increasingly arranged on vehicles, including antennas for receiving broadcast waves with frequencies up to 710 MHz such as FM (Frequency Modulation), DAB (Digital Audio Broadcast), and terrestrial digital television broadcast waves (DTV), antennas for ITS (Intelligent Transport Systems) that receive frequencies in the 760 MHz band, GNSS (Global Navigation Satellite System) antennas in the 1.2 GHz band or 1.6 GHz band using satellite communication, and further communication antennas such as 4G-LTE (4th Generation Mobile Communication System-Long Term Evolution) antennas or 5G-Sub6 (5th Generation Mobile Communication System-Sub6) antennas that transmit and receive frequencies up to 6 GHz in the infotainment band or V2X (Vehicle to Everything) band. Attempts have been made to arrange such antennas on the glass plates of vehicles (see, for example, Japanese Patent Application Laid-Open No. 2009-44697).

[0003] Japanese Patent Application Laid-Open No. 2009-44697 discloses a technique of forming an EBG (electromagnetic bandgap) on the front glass at the boundary between the front glass and the vehicle frame, with a film antenna attached to the upper part of the front glass of the vehicle. Japanese Patent Application Laid-Open No. 2009-44697 describes that this can suppress a decrease in radiation resistance (impedance) and obtain good electrical characteristics.

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the technology described in Japanese Patent Publication No. 2009-44697 has a problem in that, because the EBG is positioned along the frame to which the film antenna is closest, surface waves propagating within the metal-framed windshield cannot be adequately controlled, resulting in a decrease in antenna gain.

[0005] Considering the above facts, the present invention aims to provide a glass plate with an EBG structure and a vehicle antenna device that can control the surface waves of the glass plate and suppress the decrease in antenna gain. [Means for solving the problem]

[0006] The EBG structure-equipped glass plate according to the present invention comprises a glass plate for a vehicle that is attached to the metal frame of the vehicle body, an EBG structure disposed on the main surface of the glass plate and formed in a frame shape by periodically arranging a predetermined conductor pattern, and a radio wave transmission and reception area surrounded by the EBG structure. [Effects of the Invention]

[0007] According to the EBG structure-equipped glass plate of the present invention, the surface wave of the glass plate can be controlled to suppress the decrease in antenna gain. [Brief explanation of the drawing]

[0008] [Figure 1] This is a plan view of a vehicle to which the vehicle antenna device according to the first embodiment is applied, as seen from the vertical direction. [Figure 2] This is a schematic plan view showing the roof glass and its surrounding components as seen from outside the vehicle interior in the thickness direction, according to the first embodiment. [Figure 3] This is a cross-sectional view showing the roof glass according to the first embodiment, and shows the AA section in Figure 2. [Figure 4] This is a perspective view showing an antenna according to the first embodiment. [Figure 5] This is a cross-sectional view showing the antenna according to the first embodiment, and shows the BB cross-section of Figure 4. [Figure 6]This is a perspective view showing a part of the EBG structure according to the first embodiment. [Figure 7] This is a plan view showing an enlarged portion of the EBG structure according to the first embodiment. [Figure 8A] This is a comparative example of an analytical model diagram showing an analytical model in which an antenna is placed on a roof glass attached to a metal frame, and it is a plan view seen from the thickness direction of the roof glass. [Figure 8B] This is a comparative example of an analytical model diagram showing an antenna placed on a roof glass attached to a metal frame, and is an enlarged plan view showing a close-up of the area around the antenna. [Figure 9] Figure 8A is an analytical diagram showing the directional characteristics of the analytical model. [Figure 10] This is an analytical model diagram showing an analytical model in which an antenna is placed on a glass plate. [Figure 11A] Figure 10 is an analysis diagram showing the results of the analysis model, illustrating the electric field distribution. [Figure 11B] Figure 10 is an analysis diagram showing the analysis results of the analysis model, illustrating the directional characteristics. [Figure 12] This is an analytical model diagram showing an analytical model in which an antenna and a single EBG structure are placed on a glass plate. [Figure 13A] Figure 12 is an analysis diagram showing the results of the analysis model, illustrating the electric field distribution. [Figure 13B] Figure 12 is an analysis diagram showing the analysis results of the analysis model, illustrating the directional characteristics. [Figure 14] This is an analytical model diagram showing an analytical model in which an antenna and a double EBG structure are placed on a glass plate. [Figure 15A] Figure 14 is an analysis diagram showing the results of the analysis model, illustrating the electric field distribution. [Figure 15B] Figure 14 is an analysis diagram showing the analysis results of the analysis model, illustrating the directional characteristics. [Figure 16] This is an analytical model diagram showing an analytical model in which an antenna and a six-layer EBG structure are arranged on a glass plate. [Figure 17A]An analysis diagram showing the analysis results of the analysis model shown in FIG. 16, which shows the electric field distribution. [Figure 17B] An analysis diagram showing the analysis results of the analysis model shown in FIG. 16, which shows the directivity characteristics. [Figure 18] A perspective view of the windshield according to the second embodiment as viewed from the interior of the vehicle toward the front of the vehicle. [Figure 19] A cross-sectional view showing the windshield according to the second embodiment, showing the C-C cross-section of FIG. 18. [Figure 20] A cross-sectional view showing the windshield according to the third embodiment, showing the C-C cross-section of FIG. 18. [Figure 21] A cross-sectional view showing the windshield according to the fourth embodiment, showing the C-C cross-section of FIG. 18. [Embodiments for Carrying Out the Invention]

[0009] [First Embodiment] Hereinafter, the glass plate with an EBG structure and the vehicle antenna device according to the first embodiment will be described with reference to the drawings. In each figure, the X-axis appropriately shown is parallel to the vehicle width direction, the Y-axis is parallel to the vehicle longitudinal direction, and the Z-axis is parallel to the vehicle vertical direction. Also, the arrow FR indicates the front in the vehicle longitudinal direction, the arrow UP indicates the upper side in the vehicle vertical direction, and the arrow RH indicates the right side in the vehicle width direction. Also, among the vertical directions, the upward direction is the zenith direction, the direction opposite to the zenith direction (downward) is the nadir direction, and the direction perpendicular to the vertical direction is the horizontal direction. Further, the XY plane is a plane passing through the X-axis and the Y-axis, the XZ plane is a plane passing through the X-axis and the Z-axis, and the YZ plane is a plane passing through the Y-axis and the Z-axis. In the following description, the vehicle 10 is located on a horizontal plane, the vehicle vertical direction and the vertical direction coincide, and the XY plane and the horizontal plane coincide, and the vertical direction corresponds to the normal direction to the horizontal plane.

[0010] An example of applying the glass plate with an EBG structure and the vehicle antenna device of the first embodiment to an ordinary automobile (hereinafter referred to as a vehicle) equipped with a roof glass will be described.

[0011] [Configuration] Figure 1 is a plan view of a vehicle 10 to which the vehicle antenna device 4A according to this embodiment is applied, viewed from the vertical direction. As shown in Figure 1, the vehicle 10 is equipped with a windshield (front glass) 16, a roof glass 14, and a rear glass 18, all of which are glass plates. Figure 2 is a plan view of the roof glass 14 as seen from outside the vehicle interior in the thickness direction, and Figure 3 is a cross-sectional view of AA in Figure 2. As shown in Figure 3, the windshield 16, the roof glass 14, and the rear glass 18 are attached to the metal frame (e.g., metal flange) 12C of the vehicle body by an adhesive G, such as urethane resin.

[0012] (Roof glass 14) As shown in Figures 2 and 3, the roof glass 14 is formed in a substantially rectangular plate shape and is installed so that the thickness direction is substantially vertical. The roof glass 14 can be a single-layer glass plate (single-pane glass) having a first main surface 14B as the main surface on the exterior side of the vehicle and a second main surface 14A as the main surface on the interior side of the vehicle. The roof glass 14 may also be laminated glass in which an interlayer film such as a resin film is sandwiched between a pair of glass plates. Furthermore, the laminated glass may be dimmable glass equipped with a dimming layer having a dimming function between a pair of glass plates. However, when an antenna 30, which will be described later, is provided with laminated glass having a functional layer such as a dimming film, the antenna 30 must be positioned so as not to overlap with the conductive film contained in the functional layer in the thickness direction of the glass plate. Hereafter, unless otherwise specified, the roof glass 14 will be described as single-pane glass or laminated glass without a conductive film.

[0013] As shown in Figure 2, the roof glass 14 has an EBG (Electromagnetic Band Gap) structure 20 and an antenna 30. The roof glass 14 with the EBG structure 20 attached constitutes a glass plate 4 with an EBG structure. The roof glass 14, the EBG structure 20, and the antenna 30 constitute a vehicle antenna device 4A.

[0014] As shown in Figure 2, when viewed from the thickness direction of the roof glass 14, the roof glass 14 has a radio wave transmission / reception region 30A, which is a region enclosed by the EBG structure 20. In other words, the radio wave transmission / reception region 30A is a region enclosed by the inner edge of the EBG structure 20, and when viewed from the thickness direction of the roof glass 14, the outer edge of the radio wave transmission / reception region 30A corresponds to the inner edge of the EBG structure 20.

[0015] (Metal frame 12) As shown in Figure 2, a metal frame 12, formed in a roughly rectangular frame shape, is arranged around the periphery of the roof glass 14. The metal frame 12 includes a first metal frame 12A located on the front side of the vehicle, a second metal frame 12B located on the rear side of the vehicle, a third metal frame 12C located on the left side of the vehicle, and a fourth metal frame 12D located on the right side of the vehicle.

[0016] The roof glass 14 is attached to the first metal frame 12A at its front end in the vehicle's longitudinal direction, and to the second metal frame 12B at its rear end. In addition, the roof glass 14 is attached to the third metal frame 12C at its left end in the vehicle's width direction, and to the fourth metal frame 12D at its right end.

[0017] (Antenna 30) Antenna 30 receives right-hand circularly polarized radio waves (an example of radio waves) in at least one of the 1.2GHz and 1.6GHz bands transmitted from GNSS (Global Navigation Satellite System). A patch antenna (microstrip antenna) can be used as a GNSS antenna (an example of a satellite communication antenna). Furthermore, antenna 30 is not limited to GNSS, but also receives SDARS (Satellite Digital Audio Radio Service) signals in the 2.3GHz S-band. Any antenna capable of receiving signals will suffice.

[0018] As shown in Figure 2, the antenna 30 is positioned in front of the center of the roof glass 14 in the vehicle's longitudinal direction and to the left of the center in the vehicle's width direction, when viewed from the thickness direction of the roof glass 14. In other words, the antenna 30 is positioned near the inner corner of the first metal frame 12A and the third metal frame 12C. That is, the antenna 30 is positioned near the corner of the roof glass 14.

[0019] As shown in Figure 3, the antenna 30 is attached to the metal frame 12 or the roof glass 14 via a bracket (not shown) such that the radiating surface 36C of the radiating plate 36 (described later) is spaced apart from the roof glass 14. The antenna 30 may be directly attached to the roof glass 14, or it may be attached indirectly via a dielectric material such as resin. Furthermore, the radiating surface 36C of the radiating plate 36 may be attached in contact with the interior side surface of a glass plate such as the roof glass 14.

[0020] The antenna 30 is installed such that its radiating surface 36C faces the second main surface 14A of the roof glass 14, and the normal of the radiating surface 36C points towards the zenith. In this case, the antenna 30 is installed with its radiating surface 36C approximately horizontal to the horizontal plane.

[0021] Figure 4 is a perspective view of the antenna 30, and Figure 5 is a cross-sectional view of the BB section of Figure 4. As shown in Figure 5, the antenna 30 comprises a dielectric substrate 32, a grounding conductor plate 34, a radiating plate (radiating conductor) 36, a feeding section 38A, and a connecting conductor 38.

[0022] <Dielectric substrate 32> The dielectric substrate 32 is a plate-shaped or film-shaped dielectric layer mainly composed of a dielectric material. The term "plate-shaped or film-shaped" here may include three-dimensional shapes, such as convex, concave, or wavy shapes. Similarly, the grounding conductor plate 34 and the radiating plate 36 can also be "plate-shaped or film-shaped." However, the grounding conductor plate 34 and the radiating plate 36 are preferably planar (two-dimensional). When these components are planar, it becomes easier to predict the antenna gain characteristics of the antenna 30.

[0023] As is clear from Figures 4 and 5, the dielectric substrate 32 is a rectangular parallelepiped, and its front shape is a rectangle in which the Y-axis dimension is larger than the X-axis dimension. However, the dielectric substrate 32 may also be a square in which the Y-axis dimension and the X-axis dimension are equal, or it may be any shape including a polygon, a circle, or a curve. As shown in Figure 5, the dielectric substrate 32 has a surface 32A, which is one surface in the thickness direction, and a surface 32B, which is the other surface. Surfaces 32A and 32B are planes parallel to each other. The dielectric substrate 32 may be made of, for example, a glass epoxy substrate, or a dielectric sheet. The dielectric material included in the dielectric substrate 32 may be, for example, glass such as quartz glass, ceramics, fluororesins such as polytetrafluoroethylene, liquid crystal polymers, or cycloolefin polymers. However, the dielectric material may be a material other than these. Furthermore, the antenna 30 may be a combination of the dielectric substrate 32 and the radiating plate 36 stacked in the thickness direction. In this case, the antenna 30 functions as a GNSS antenna that supports both the 1.2GHz and 1.6GHz frequency bands by, for example, adjusting the size of the radiating plate 36.

[0024] <Grounding conductor plate 34> A grounding conductor plate 34 is provided on the surface 32A of the dielectric substrate 32, and the grounding of the antenna 30 It functions as a grounding element. The grounding conductor plate 34 is a plate-shaped or film-shaped conductor. Both surfaces of the grounding conductor plate 34 in the thickness direction are parallel to each other. Examples of materials that make up the grounding conductor plate 34 include copper and silver, but it is not limited to these materials. The front shape of the grounding conductor plate 34 shown in the figure is a square the same size as the dielectric substrate 32. However, the front shape of the grounding conductor plate 34 may be a shape other than a square. For example, the front shape of the grounding conductor plate 34 may be a rectangle, a polygon, or a circle.

[0025] <Radiating plate 36> A radiating plate 36 is provided on the surface 32B of the dielectric substrate 32. The radiating plate 36 is a plate-shaped or film-shaped conductor, and its area is smaller than that of the ground conductor plate 34. The radiating plate 36 is a plate-shaped layer, and the radiating surface 36C, which is the side opposite to the dielectric substrate 32, is planar. The radiating plate 36 functions as a radiating element of the antenna 30. Examples of materials that make up the radiating plate 36 include copper and silver, but it is not limited to these materials. The front shape of the illustrated radiating plate 36 is approximately square, and it has notches at a pair of opposing corners. In this way, the radiating plate 36 is configured to receive circularly polarized signals by having notches. The notches correspond to known degenerate separation elements and perturbation elements, and the area of ​​the part that is removed from the square when there are no notches can be set to an area determined by the degenerate separation method. Alternatively, the antenna 30 may be configured to transmit and receive circularly polarized signals by providing two feed points on a roughly square radiating plate that does not have notches at a pair of opposing corners.

[0026] <Power supply section 38A> The power supply section 38A is a part that is supplied with power by contact or non-contact, and is the part to which one end of a power supply line (not shown in the illustration) is connected or is adjacent. Specific examples of power supply lines include coaxial cables, striplines, microstrip lines, and coplanar power supply lines. The other end of the power supply line is connected to a communication device (ECU: Electronic Control Unit) that controls the signal from the antenna 30.

[0027] <Connecting conductor 38> The connecting conductor 38 is provided inside a through-hole that penetrates the dielectric substrate 32 in the direction of its thickness. The connecting conductor 38 is, for example, the core wire or conductor pin of a coaxial cable, but is not limited to these. One end of the connecting conductor 38 is connected to the power supply section 38A, and the other end of the connecting conductor 38 is connected to the connection point 36A of the radiating plate 36. The connecting conductor 38 does not come into contact with the grounding conductor plate 34.

[0028] As shown in Figure 4, in a front view (viewed from the thickness direction of the dielectric substrate 32), the connection point 36A is located away from the center of gravity 36B of the radiating plate 36. Note that when the medium between the grounding conductor plate 34 and the radiating plate 36 includes space (air), the connecting conductor 38 can be, for example, the core wire or conductor pin of a coaxial cable, but the connecting conductor 38 in this case is not limited to these. As shown in Figure 5, the center of gravity 36B of the radiating plate 36 and the center of gravity 34A of the grounding conductor plate 34 are located on a straight line PL that passes through the radiating plate 36 in its thickness direction.

[0029] (Radio wave transmission / reception area 30A) The radio wave transmission / reception area 30A is the area in which the antenna 30 transmits and receives radio waves, or at least one of the other. As shown in Figure 2, the radio wave transmission / reception area 30A is the area enclosed by the EBG structure 20 when viewed from the thickness direction of the roof glass 14, and is formed in a rectangular shape. As shown in Figure 3, the radio wave transmission / reception area 30A is formed to be wider than the area obtained by perpendicularly projecting the outline of the radiating surface 36C onto the roof glass 14.

[0030] (EBG structure 20) As shown in Figures 2 and 3, the EBG structure 20 is bonded, for example, with an adhesive. It is attached to the second main surface 14A of the glass 14. The EBG structure 20 is formed in a rectangular frame shape, with predetermined conductor patterns (unit cells) arranged periodically to continuously surround the radio wave transmission and reception area 30A. The conductors constituting the EBG structure 20 can be made of metals such as copper and silver, but are not limited to these; using transparent conductors improves visibility. Furthermore, even if the conductors constituting the EBG structure 20 are opaque, visibility can be improved by using conductors processed into a mesh pattern.

[0031] As shown in Figure 2, the EBG structure 20 is positioned in front of the center of the roof glass 14 in the vehicle's longitudinal direction and to the left of the center in the vehicle's width direction, when viewed from the thickness direction of the roof glass 14. In other words, the EBG structure 20 is positioned near the inner corner of the first metal frame 12A and the third metal frame 12C. That is, the EBG structure 20 is positioned near the corner of the roof glass 14, but the positioning of the EBG structure 20 is not limited to the vicinity of the corner.

[0032] The EBG structure 20 is arranged in a double layer between the antenna 30 and the metal frame 12, consisting of a first EBG structure 20A and a second EBG structure 20B positioned on the outer periphery of the first EBG structure 20A. The EBG structure 20 may be formed as a single layer or as three or more layers. The EBG structure 20 may also be made of a transparent or translucent material. However, if the EBG structure 20 is made of an opaque material, an increase in the number of unit cells may reduce visibility. Furthermore, an increase in the number of unit cells may increase the amount of work required and reduce productivity (yield).

[0033] Furthermore, the roof glass 14 may have a light-shielding film (not shown) on its periphery. The light-shielding film is an opaque colored ceramic layer with a thickness of about 5 μm to 25 μm. The color is arbitrary, but dark colors such as black, brown, gray, dark blue, or white are preferred, with black being more preferred. When viewed from the thickness direction of the roof glass 14, if the light-shielding film overlaps with part or all of the EBG structure 20, visibility is improved. Furthermore, if the light-shielding film overlaps with the entire EBG structure 20, visibility is improved, but the area of ​​the opening (transmitted region) of the roof glass 14 becomes smaller, so it is advisable to adjust as appropriate. Note that the light-shielding film may also be present on the periphery of glass plates other than the roof glass 14, such as the windshield 16 and rear glass 18 in the embodiments described later, and similarly, visibility is improved.

[0034] Figure 6 is a perspective view showing a part of the EBG structure 20, and Figure 7 is an enlarged plan view showing a part of the EBG structure 20. As shown in Figure 6, the first EBG structure 20A and the second EBG structure 20B are formed in a thin, plate-like planar shape using a base material 22 and a conductor portion 24. A predetermined conductor pattern 26, which is a unit pattern formed by the conductor portion 24, is periodically arranged in the first EBG structure 20A and the second EBG structure 20B. The conductor pattern 26 is set to suppress the propagation of radio waves in a predetermined frequency band (e.g., 1.6 GHz band) transmitted and received by the antenna 30.

[0035] As shown in Figure 7, the conductor portion 24 of one conductor pattern 26 has a main patch 24A, a subpatch 24B, and a bridge portion 24C.

[0036] The main patch 24A is formed in the shape of a rectangular plate and is positioned approximately in the center of the conductor pattern 26. The sub-patches 24B are also formed in the shape of a rectangular plate and are arranged in groups of four around the main patch 24A, with a portion of each connected to the main patch 24A.

[0037] The bridge sections 24C are formed in a rectangular plate shape and four of them are provided so as to extend radially from the main patch 24A. The bridge sections 24C are formed to connect the main patches 24A of adjacent conductor patterns 26. The conductor pattern 26 is shown in Figure 6. Regardless of its shape, it can be adjusted as needed to match the corresponding frequency band.

[0038] In the example of the vehicle antenna device 4A shown in Figure 2, the shortest distance D1 between the outer edge of the EBG structure 20 on the vehicle front side and the front end edge 15A of the roof glass 14 on the vehicle front side, viewed from the thickness direction of the roof glass 14, is set to be shorter than the shortest distance D3 between the outer edge of the EBG structure 20 on the vehicle left side and the left end edge 15C of the roof glass 14 on the vehicle left side. Also, viewed from the thickness direction of the roof glass 14, the shortest distance D3 is set to be shorter than the shortest distance D2 between the outer edge of the EBG structure 20 on the vehicle rear side and the rear end edge 15B of the roof glass 14 on the vehicle rear side. Furthermore, viewed from the thickness direction of the roof glass 14, the shortest distance D2 is set to be shorter than the shortest distance D4 between the outer edge of the EBG structure 20 on the vehicle right side and the right end edge 15D of the roof glass 14 on the vehicle right side. Hereinafter, the shortest distances D1 to D4 will also be simply referred to as D1 to D4.

[0039] In other words, D1, D2, D3, and D4 are set to different distances. To put it another way, in the example of the vehicle antenna device 4A shown in Figure 2, the shortest distance between the first side forming the outer edge of the roof glass 14 and the outer edge of the EBG structure 20 is different from the shortest distance between the other second side forming the outer edge of the roof glass 14 and the outer edge of the EBG structure 20. Note that D1 and D3 may be the same distance, and D1, D2, D3, and D4 can be set to match any position where the antenna 30 is placed.

[0040] In the example of the vehicle antenna device 4A shown in Figure 2, when viewed from the thickness direction of the roof glass 14, D2 and D4 are formed to be longer than the longest distance L from the centroid P1 of the radio wave transmitting / receiving area 30A to the outer edge of the radio wave transmitting / receiving area 30A. In other words, D2 and D4 are formed to be longer than the distance from the centroid P1 of the radio wave transmitting / receiving area 30A to the corner of the radio wave transmitting / receiving area 30A. Note that at least one of D1, D2, D3, and D4 may be formed to be longer than the longest distance L from the centroid P1 of the radio wave transmitting / receiving area 30A to the outer edge of the radio wave transmitting / receiving area 30A.

[0041] Thus, in the example of the vehicle antenna device 4A shown in Figure 2, the center of gravity P1 of the radio wave transmission and reception area is formed at a different position from the center of gravity P2 of the roof glass 14.

[0042] Furthermore, when viewed from the thickness direction of the roof glass 14, the EBG structure 20 is formed at a distance G from the antenna 20. In other words, when viewed from the thickness direction of the roof glass 14, the antenna 30 is surrounded by the EBG structure 20 at equal distances G apart, and the space between them is formed in a rectangular loop shape. That is, this rectangular loop corresponds to a region consisting only of dielectric material (glass plate) that does not have a conductor. Note that the antenna 30 may be surrounded by the EBG structure 20 at different distances in the vehicle's longitudinal direction and in the vehicle's width direction.

[0043] [Electric field distribution analysis and directivity analysis] The following describes the electric field distribution analysis and directivity analysis performed to confirm the effects of the EBG structure-equipped glass plate 4 and the vehicle antenna device 4A of the first embodiment.

[0044] (Analysis 1) Figures 8A and 8B are diagrams showing an analysis model that serves as a comparative example for vehicle antenna device 4A. As shown in Figures 8A and 8B, in Analysis 1, a vehicle antenna device model of Example 1 was created as a comparative example. The vehicle antenna device model of Example 1 includes a metal frame model 12M as an analysis model of the metal frame 12, a roof glass model 14M as an analysis model of the roof glass 14, and an antenna model 30M as an analysis model of the antenna 30.

[0045] In Figure 8A, the roof glass model 14M is rectangular, and the width W1 in the vehicle width direction is The width was set to 800 mm, and the length W2 in the longitudinal direction of the vehicle was set to 500 mm. A metal frame 12 was provided around the periphery of the roof glass model 14M. In Figure 8B, the width T1 in the shorter direction of the metal frame 12 was set to 10 mm.

[0046] Antenna model 30M was set to a 30 x 30 mm square when viewed from the front. The distance T2 between antenna model 30M (the end of the grounding conductor plate 34 in Figure 3) and the first metal frame model 12AM was set to 5 mm. Furthermore, antenna model 30M was positioned in the center of the roof glass model 14M in the vehicle width direction.

[0047] For the vehicle antenna device model of Example 1 created as described above, a directivity analysis of right-hand circular polarization in the vertical plane at a frequency of 1.5754 [GHz] was performed.

[0048] Figure 9 shows the analysis results for "Analysis 1," illustrating the antenna gain and directivity of antenna model 30M as viewed from the horizontal direction of the vehicle. As can be seen from Figure 9, the following analysis results were obtained. Main robe size: 3.7 [dBi] Main robe direction: 25.0 [deg] 3dB half-width: 19.8 [deg] Side lobe level: -0.9 [dB] Furthermore, Figure 9 shows that in "Analysis 1," ripple occurs in the antenna gain, and the antenna gain in the zenith direction decreases.

[0049] (Analysis 2) Figure 10 is an analytical model diagram showing an antenna placed on a glass plate without a metal frame. As shown in Figure 10, in Analysis 2, a vehicle antenna device model for Example 2 was created as an ideal reference example. The vehicle antenna device model for Example 2 includes a roof glass model 14M as an analytical model of the roof glass 14 and an antenna model 30M as an analytical model of the antenna 30.

[0050] Antenna model 30M was positioned in the center of the vehicle width direction and in the center of the vehicle longitudinal direction of roof glass model 14M. Roof glass model 14M was rectangular, with a width W3 in the vehicle width direction of 807.4 [mm].

[0051] An electric field distribution analysis was performed on the vehicle antenna device model Example 2, which was created as described above. Figure 11A is the electric field distribution diagram of antenna model 30M along the glass surface in "Analysis 2". Figure 11B is the analysis result showing the antenna gain and directivity of antenna model 30M as viewed from the horizontal direction of the vehicle in "Analysis 2".

[0052] Figure 11A shows that the outlines of the first region R1, which has the strongest electric field strength, the second region R2, which is formed outside the first region and has a weaker electric field strength than the first region R1, the third region R3, which is formed outside the second region and has a weaker electric field strength than the second region R2, and the fourth region R4, which is formed outside the third region and has a weaker electric field strength than the third region R3, are formed in roughly concentric circles around antenna model 30M. Furthermore, a fifth region R5, which has a weaker electric field strength than the fourth region R4, is formed outside the fourth region.

[0053] Furthermore, the electric field strength at measurement point Q, located at a distance U in the vehicle width direction from antenna model 30M, was 2.3 [V / m].

[0054] Furthermore, a directivity analysis of right-hand circular polarization in the vertical plane at a frequency of 1.57542 [GHz] was performed on the vehicle antenna device model of Example 2 created as described above.

[0055] As can be seen from Figure 11B, the following analysis results were obtained. Main robe size: 3.6 [dBi] Main robe direction: 10.0 [deg] 3dB half-width: 112.0 [deg] Side lobe level: -28.5 [dB] Furthermore, Figure 11B shows that in "Analysis 2," no ripple occurs in the antenna gain, and stable directivity is obtained.

[0056] From this, it can be seen that in "Analysis 2," the directivity in the zenith direction is improved compared to "Analysis 1," in which the metal frame model 12M was created. In other words, it can be seen that the vehicle antenna device model, which has only the metal frame 12 and antenna 30, has a disturbed beam (antenna gain) and a decrease in directivity in the zenith direction.

[0057] (Analysis 3) Figure 12 is an analysis model diagram showing an antenna placed on a glass plate without a metal frame. As shown in Figure 12, in "Analysis 3," a vehicle antenna device model 4AM of Example 3, which is an embodiment of the first embodiment, was created. The vehicle antenna device model 4AM of Example 3 includes a roof glass model 14M as an analysis model of the roof glass 14, an antenna model 30M as an analysis model of the antenna 30, and a single EBG structure model 20M as an analysis model of the EBG structure 20.

[0058] Antenna model 30M was positioned at the center of the roof glass model 14M in the vehicle width direction and at the center of the vehicle in the vehicle longitudinal direction. The roof glass model 14M was rectangular, with a width W3 in the vehicle width direction of 807.4 [mm]. The distance S from the center of antenna model 30M to the inner edge of EBG structure model 20M was 36.7 [mm].

[0059] An electric field distribution analysis was performed on the vehicle antenna device model 4AM of Example 3, which was created as described above. Figure 13A is the electric field distribution diagram of antenna model 30M along the glass surface in "Analysis 3". Figure 13B is the analysis result showing the antenna gain and directivity of antenna model 30M as viewed from the horizontal direction of the vehicle in "Analysis 3".

[0060] Figure 13A shows that the outlines of the first region R1, the second region R2, the third region R3, and the fourth region R4 are formed in a roughly rectangular shape, and are smaller compared to Example 2. Also, the electric field strength at measurement point Q, which is a distance U in the vehicle width direction from antenna model 30M, was 2.1 [V / m].

[0061] This indicates that the placement of the EBG structure 20 suppresses surface waves propagating through the roof glass 14.

[0062] Furthermore, a directivity analysis of right-hand circular polarization in the vertical plane at a frequency of 1.57542 [GHz] was performed on the vehicle antenna device model 4AM of Example 3, which was created as described above.

[0063] As can be seen from Figure 13B, the following analysis results were obtained. Main robe size: 4.43 [dBi] Main robe direction: 7.0 [deg] 3dB half-width: 97.2 [deg] Side lobe level: -29.0 [dB] Furthermore, as shown in Figure 13B, in "Analysis 3," no ripple occurred in the antenna gain, and stable directivity was obtained. In addition, compared to "Analysis 2," the main lobe was larger. It becomes clear that...

[0064] This indicates that the directivity in the zenith direction is improved by arranging the EBG structure 20. Note that in "Analysis 3," a model using a glass plate without a metal frame was used for convenience, but similar results can be obtained with a model having a metal frame (roof glass), as in Example 1.

[0065] (Analysis 4) Figure 14 is an analysis model diagram showing an antenna placed on a glass plate without a metal frame. As shown in Figure 14, in "Analysis 4," a vehicle antenna device model 4AM of Example 4, which is an embodiment of the first embodiment, was created. The vehicle antenna device model 4AM of Example 4 includes a roof glass model 14M as an analysis model of the roof glass 14, an antenna model 30M as an analysis model of the antenna 30, and a double EBG structure model 20M as an analysis model of the EBG structure 20.

[0066] Antenna model 30M was positioned at the center of the roof glass model 14M in the vehicle width direction and at the center of the vehicle in the vehicle longitudinal direction. The roof glass model 14M was rectangular, with a width W3 in the vehicle width direction of 807.4 [mm]. The distance S from the center of antenna model 30M to the inner edge of EBG structure model 20M was 36.7 [mm].

[0067] An electric field distribution analysis was performed on the vehicle antenna device model 4AM of Example 4, which was created as described above. Figure 15A is the electric field distribution diagram of antenna model 30M along the glass surface in "Analysis 4". Figure 15B is the analysis result showing the antenna gain and directivity of antenna model 30M as viewed from the horizontal direction of the vehicle in "Analysis 4".

[0068] Figure 15A shows that the outlines of the first region R1, the second region R2, the third region R3, and the fourth region R4 are formed in the shape of a four-leaf clover, and are smaller compared to Example 3. Also, the electric field strength at measurement point Q, which is a distance U in the vehicle width direction from antenna model 30M, was 1.7 [V / m].

[0069] This indicates that by arranging the EBG structure 20 in a double layer, surface waves propagating through the roof glass 14 are further suppressed.

[0070] Furthermore, a directivity analysis of right-hand circular polarization in the vertical plane at a frequency of 1.57542 [GHz] was performed on the vehicle antenna device model 4AM of Example 4, which was created as described above.

[0071] As can be seen from Figure 15B, the following analysis results were obtained. Main robe size: 4.28 [dBi] Main robe direction: 3.0 [deg] 3dB half-width: 87.2 [deg] Furthermore, Figure 15B shows that in "Analysis 4," no antenna gain ripple occurred, and stable directivity was obtained. In addition, it can be seen that the half-width was narrowed by 3 dB compared to "Analysis 3."

[0072] This shows that arranging the EBG structure 20 in a double layer improves the antenna gain in the zenith direction. In "Analysis 4," for convenience, a model using a glass plate without a metal frame was used, but similar results can be obtained with a model having a metal frame (roof glass) as in Example 1.

[0073] (Analysis 5) Figure 16 is an analysis model diagram showing an antenna placed on a glass plate without a metal frame. As shown in Figure 16, in "Analysis 5", a vehicle antenna device model 4AM of Example 5, which is an embodiment of the first embodiment, was created. The vehicle antenna device model 4AM of Example 5 includes a roof glass model 14M as an analysis model of the roof glass 14, an antenna model 30M as an analysis model of the antenna 30, and a six-layer EBG structure model 20M as an analysis model of the EBG structure 20.

[0074] Antenna model 30M was positioned at the center of the roof glass model 14M in the vehicle width direction and at the center of the vehicle in the vehicle longitudinal direction. The roof glass model 14M was rectangular, with a width W3 in the vehicle width direction of 807.4 [mm]. The distance S from the center of antenna model 30M to the inner edge of EBG structure model 20M was 36.7 [mm].

[0075] An electric field distribution analysis was performed on the vehicle antenna device model 4AM of Example 5, which was created as described above. Figure 17A is the electric field distribution diagram of antenna model 30M along the glass surface in "Analysis 5". Figure 17B is the analysis result showing the antenna gain and directivity of antenna model 30M as viewed from the horizontal direction of the vehicle in "Analysis 5".

[0076] Figure 17A shows that the fourth region R4 is formed slightly outside the EBG structure model 20M. Also, the electric field strength at measurement point Q, which is a distance U in the vehicle width direction from antenna model 30M, was 1.7 [V / m].

[0077] This indicates that by arranging the EBG structure 20 in six layers, surface waves propagating through the roof glass 14 are further suppressed.

[0078] Furthermore, a directivity analysis of right-hand circular polarization in the vertical plane at a frequency of 1.57542 [GHz] was performed on the vehicle antenna device model 4AM of Example 5, which was created as described above.

[0079] As can be seen from Figure 17B, the following analysis results were obtained. Main robe size: 3.06 [dBi] Main robe direction: 7.0 [deg] 3dB half-width: 90.9 [deg] Furthermore, Figure 15B shows that in "Analysis 5," no antenna gain ripple occurred, and stable directivity was obtained. In addition, it can be seen that the half-width was narrowed by 3 dB compared to "Analysis 3."

[0080] This shows that arranging the EBG structure 20 in a six-layer configuration improves the antenna gain in the zenith direction. In "Analysis 5," for convenience, a model using a glass plate without a metal frame was used, but similar results can be obtained with a model having a metal frame (roof glass) as in Example 1.

[0081] [Operation of the First Embodiment] Next, the operation and effects of the glass plate 4 with EBG structure and the vehicle antenna device 4A of the first embodiment will be described.

[0082] In the first embodiment, the EBG structure 20 is placed on the second main surface 14A of the roof glass 14, so that when the antenna 30 transmits and receives radio waves in the radio wave transmission / reception area 30A, the propagation of radio waves on the surface of the roof glass 14 is suppressed. As a result, the radio waves transmitted and received in the radio wave transmission / reception area 30A can propagate through the glass plate and re-radiation at the metal frame 12 can be suppressed. As a result, the surface waves of the roof glass 14 can be controlled and the decrease in antenna gain can be suppressed.

[0083] Furthermore, because the EBG structure 20 is formed to surround the radio wave transmission / reception area 30A in a frame-like manner, when the antenna 30 transmits and receives radio waves in the radio wave transmission / reception area 30A, the propagation of radio waves can be suppressed in any direction within the plane of the roof glass 14. As a result, the radio waves transmitted and received by the antenna 30 in the radio wave transmission / reception area 30A can propagate through the glass plate and further suppress re-radiation in the metal frame. Consequently, the surface waves of the roof glass 14 can be controlled, and the decrease in antenna gain can be sufficiently suppressed.

[0084] Furthermore, by forming D2 and D4 to be longer than the longest distance L from the center of gravity P1 of the radio wave transmission / reception area 30A to the outer edge of the radio wave transmission / reception area 30A, the EBG structure 20 is positioned eccentrically from the center of gravity P2 of the roof glass 14. As a result, the EBG structure 20 and the radio wave transmission / reception area 30A can be made difficult for occupants to see.

[0085] Furthermore, if the radio wave transmission / reception area 30A is rectangular in shape, a rectangular antenna 30 can be installed in an appropriate position within the radio wave transmission / reception area 30A. For example, a general-purpose patch antenna can be appropriately placed within the radio wave transmission / reception area 30A.

[0086] D1 is different from D2 and at least one of D3 and D4, so that the center of gravity of the EBG structure 20 and the center of gravity P2 of the roof glass 14 are different, for example, D1 may be formed at a position eccentric with respect to the roof glass 14. As a result, the EBG structure 20 is positioned to ensure visibility for the occupants.

[0087] The EBG structure 20 is arranged in a double or double layer, which suppresses the propagation of radio waves on the surface of the roof glass 14 when transmitting and receiving radio waves in the radio wave transmission / reception area 30A. As a result, the radio waves transmitted and received by the antenna 30 in the radio wave transmission / reception area 30A propagate through the roof glass 14, further suppressing re-radiation at the metal frame 12. Consequently, the glass plate 4 with the EBG structure can adequately control the surface waves of the roof glass 14, further suppressing the decrease in antenna gain.

[0088] The planar EBG structure 20 is positioned on the second main surface 14A of the roof glass 14, so that the EBG structure 20 does not protrude from the second main surface 14A of the roof glass 14. Therefore, it is less likely that the EBG structure 20 will reduce the interior space of the vehicle.

[0089] Furthermore, the vehicle antenna device 4A is installed such that the radiating surface 36C of the antenna 30 is spaced apart from the roof glass 14, so that the radiating surface 36C does not come into contact with the roof glass 14. Alternatively, the radiating surface 36C may come into contact with the inner surface of the roof glass 14, in which case space saving can be easily achieved.

[0090] Furthermore, in the vehicle antenna device 4A, the radiating surface 36C of the antenna 30 is positioned approximately parallel to the horizontal plane, so that the radiating surface 36C is oriented towards the zenith. Note that "approximately parallel to the horizontal plane" refers to a range of ±15° with respect to the horizontal plane, but it may also be within a range of ±10°, ±5°, or ±3°, but 0° with respect to the horizontal direction is most preferable. As a result, the antenna gain of the vehicle antenna device 4A, including antennas for satellite communications such as GNSS, is improved.

[0091] [Second Embodiment] The glass plate with EBG structure and vehicle antenna device of the second embodiment differ from the glass plate with EBG structure and vehicle antenna device of the first embodiment mainly in the configuration of the antenna.

[0092] [composition] The configuration of the glass plate with EBG structure and the vehicle antenna device of the second embodiment will be described below. In addition, the same terms or reference numerals will be used to describe parts that are the same as or equivalent to those described in the first embodiment.

[0093] (Windshield 16) Figure 18 is a view of the vehicle antenna device 6A, including the windshield 16, from inside the vehicle, and Figure 19 is a cross-sectional view of the CC section in Figure 18. As shown in Figure 18, the windshield 16 is positioned above the instrument panel 15 in the vehicle's vertical direction and is formed in a substantially rectangular plate shape. As shown in Figure 19, the windshield 16 is often installed such that the plate thickness direction is inclined from the vertical direction toward the front of the vehicle. For example, the angle between the horizontal direction (here, the vehicle's longitudinal direction) and the windshield 16 is about 22.5°.

[0094] The windshield 16 is a laminated glass having a first glass plate 16-1, a second glass plate 16-2, and an interlayer 17.

[0095] The first glass plate 16-1 has a first main surface 16A as the main surface on the exterior side of the vehicle and a second main surface 16B as the main surface on the interior side of the vehicle. The second glass plate 16-2 has a third main surface 16C as the main surface on the exterior side of the vehicle and a fourth main surface 16D as the main surface on the interior side of the vehicle.

[0096] An interlayer 17 is attached to the second main surface 16B and the third main surface 16C, respectively, and two layers of interlayer 17 are interposed between the first glass plate 16-1 and the second glass plate 16-2. The interlayer 17 can be a thin film made of, for example, PVB (polyvinyl butyral), ethylene-vinyl acetate copolymer (EVA), or cycloolefin polymer (COP).

[0097] An EBG structure 20 is interposed between the two interlayer films 17. While Figure 19 shows a simplified representation of the EBG structure 20 within the laminated glass, in reality, the thin film EBG structure 20 is completely sealed by the two interlayer films 17. The thickness of each of the two interlayer films 17 can be exemplified as 0.38 mm.

[0098] Furthermore, the EBG structure 20 may be placed on at least one surface of the (single-layer) interlayer film 17 (for example, 0.76 mm thick). In other words, the EBG structure 20 can be exemplified by having a thickness of about 10 μm to 20 μm, and may be formed on at least one of the second main surface 16B and the third main surface 16C, or on either one. In this case, the EBG structure 20 may have a planar thin film shape that is thinner than the interlayer film 17, and may be formed on at least one of the first glass plate 16-1 and the second glass plate 16-2. Also, the shape and size of the conductor pattern 26 of the EBG structure 20 may be appropriately adjusted, such as by adjusting the width of the rectangular loop shape, to match the inclined windshield 16.

[0099] As shown in Figure 19, the windshield 16 has an EBG structure 20 and an antenna 130. The windshield 16 with the EBG structure 20 attached constitutes a glass plate 6 with an EBG structure. The windshield 16, the EBG structure 20, and the antenna 130 constitute a vehicle antenna device 6A.

[0100] The EBG structure 20 and the antenna 130 may be installed on the rear window 18 or on the side window.

[0101] (Metal frame 12) As shown in Figure 18, a metal frame 12, formed in a roughly rectangular frame shape, is arranged around the periphery of the windshield 16. The metal frame 12 is positioned on the upper side in the vertical direction of the vehicle. It has a first metal frame 12A, a fifth metal frame 12E positioned on the lower side in the vertical direction of the vehicle, a sixth metal frame 12F positioned on the left side in the width direction of the vehicle, and a seventh metal frame 12G positioned on the right side in the width direction of the vehicle.

[0102] The windshield 16 is attached to the first metal frame 12A at its upper end in the vehicle's vertical direction and to the fifth metal frame 12E at its lower end. In addition, the windshield 16 is attached to the sixth metal frame 12F at its left end in the vehicle's width direction and to the seventh metal frame 12G at its right end.

[0103] (Antenna 130) Antenna 130 is a patch antenna (microstrip antenna) used as a V2X antenna to transmit and receive vertically polarized radio waves (an example of radio waves) in the 5.8GHz or 5.9GHz band, which are used for vehicle-to-vehicle communication and vehicle-to-infrastructure communication.

[0104] Antenna 130 has substantially the same configuration as antenna 30 shown in the first embodiment, except that the configuration of the radiating plate 136 is different. The front shape of the radiating plate 136 is a square without a notch (unlike the aforementioned radiating plate 36). However, the front shape of the radiating plate 136 may be a rectangle other than a square, and may be a rectangle, polygon, or circle.

[0105] As shown in Figure 18, when viewed from inside the vehicle towards the front of the vehicle, the antenna 130 is positioned above the center of the windshield 16 in the vertical direction of the vehicle and to the left of the center in the width direction of the vehicle. In other words, the antenna 130 is positioned near the inner corner between the first metal frame 12A and the sixth metal frame 12F.

[0106] As shown in Figure 19, the antenna 30 is attached to the metal frame 12 or the windshield 16 via a bracket (not shown) such that the radiating surface 136C of the radiating plate 136 is spaced apart from the windshield 16. The antenna 130 is located on the interior side of the vehicle relative to the radiating surface 136C. The antenna 130 is mounted so that the normal to the radiating surface 136C is oriented horizontally. In other words, the antenna 130 is mounted so that the radiating surface 136C is approximately parallel to the vertical direction. Note that "approximately parallel to the vertical direction" refers to a range of ±15° with respect to the vertical direction, but may also be within a range of ±10°, ±5°, ±3°, or 0°.

[0107] Furthermore, the radio wave transmission and reception area 30A is formed to be larger than the area obtained by horizontally projecting the outline of the radiating surface 136C onto the windshield 16.

[0108] [Operation of the second embodiment] Next, the operation and effects of the glass plate 6 with EBG structure and the vehicle antenna device 6A of the second embodiment will be described.

[0109] In the glass plate 6 with EBG structure of the second embodiment, the windshield 16 is a laminated glass having a first glass plate 16-1, a second glass plate 16-2, and an interlayer 17 interposed between the first glass plate 16-1 and the second glass plate 16-2.

[0110] For example, by placing the EBG structure 20 between the first glass plate 16-1 and the second glass plate 16-2, the EBG structure 20 is not exposed to the outside. Therefore, the EBG structure 20 can be protected.

[0111] By arranging the radiating surface 136C approximately parallel to the vertical direction, the radiating surface 136C can ensure horizontal directivity for transmitting and receiving radio waves in vehicle-to-vehicle communication and vehicle-to-infrastructure communication, etc. In this way, the vehicle antenna device 6A can improve the antenna gain in the horizontal direction and obtain the desired directivity.

[0112] Furthermore, the other configurations and effects are substantially the same as those of the above embodiment, so their explanation will be omitted.

[0113] [Third Embodiment] The glass plate with EBG structure and vehicle antenna device of the third embodiment differ from the glass plate with EBG structure and vehicle antenna device of the second embodiment in that the arrangement of the EBG structure is different.

[0114] Figure 20 is a cross-sectional view of the CC cross section in Figure 18, showing a different arrangement of the EBG structure from the second embodiment. As shown in Figure 20, an interlayer 17 is interposed between the second main surface 16B and the third main surface 16C. An interlayer 17 (for example, 0.76 mm thick) is interposed between the first glass plate 16-1 and the second glass plate 16-2. The EBG structure 20 is attached to the fourth main surface 16D.

[0115] [Operation of the third embodiment] Next, the operation and effects of the EBG structure-equipped glass plate 106 and the vehicle antenna device 106A of the third embodiment will be described.

[0116] In the third embodiment of the glass plate 106 with an EBG structure, the EBG structure 20 is positioned on the fourth main surface 16D of the second glass plate 16-2, on the side opposite to the first glass plate 16-1.

[0117] By positioning the EBG structure 20 on the fourth main surface 16D, the EBG structure 20 is formed on the outside of the windshield 16. Therefore, it is easy to attach the EBG structure 20 to the windshield 16, such as by adding it later.

[0118] Furthermore, the other configurations and effects are substantially the same as those of the above embodiment, so their explanation will be omitted.

[0119] [Fourth Embodiment] In the second and third embodiments, examples were shown in which the antenna 130 as a V2X antenna is mounted on the windshield 16 such that the radiating surface 136C is substantially horizontal to the vertical direction of the vehicle. Figure 21 is a cross-sectional view of CC in Figure 18, showing the glass plate 206 with EBG structure and the vehicle antenna device 206A of the fourth embodiment.

[0120] As shown in Figure 21, the vehicle antenna device 206A of this embodiment uses an antenna 30 as a GNSS antenna, which is an example of a satellite communication antenna, and is mounted on the windshield 16 such that the radiating surface 136C is substantially horizontal to the horizontal plane. In this case, the radio wave transmission and reception area 30A can be formed to be wider than the area obtained by perpendicularly projecting the outer shape of the radiating surface 136C onto the windshield 16. Alternatively, the antenna 30 as a GNSS antenna may be mounted on the rear glass 18 such that the radiating surface 136C is substantially horizontal to the horizontal plane. Furthermore, in the vehicle antenna device 206A having a satellite communication antenna, the antenna 30 may be mounted on at least one of the windshield 16 and the rear glass 18 such that the radiating surface 136C is parallel to the glass surface inside the vehicle, that is, in accordance with the mounting angle of the glass with respect to the horizontal plane (for example, 22.5°). This configuration allows for space saving in the vehicle interior where the antenna 30 is located.

[0121] The glass plate with EBG structure and the vehicle antenna device have been described above based on the embodiments described. However, the specific configuration is not limited to these embodiments, and design changes are permitted as long as they do not deviate from the gist of the invention as described in each claim of the patent.

[0122] In the above embodiment, an example was shown in which the EBG structure 20 is formed continuously to surround the radio wave transmission and reception area 30A. However, the EBG structure is not limited to this embodiment, and for example, a plurality of EBG structures may be formed to surround the radio wave transmission and reception area 30A.

[0123] In the above embodiment, the EBG structure 20 was shown as being formed in the shape of a rectangular frame. However, the EBG structure may have at least one side missing from forming the rectangle, or it may be a polygon, a circle, or other shape.

[0124] In the above embodiment, an example was shown in which the EBG structure 20 is arranged in a double row to form a rectangular closed loop. However, the EBG structure 20 may be arranged in a single row, or in three or more rows.

[0125] In the above embodiment, the EBG structure 20 was shown as being formed in a thin, planar shape from a base material 22 and a conductor portion 24. However, the EBG structure is not limited to this embodiment, and may also be a three-dimensional shape in the form of a so-called mushroom structure, composed of a metal patch on a dielectric substrate and metal vias connecting the patch to a ground conductor on the back surface of the substrate, or any general EGB structure.

[0126] In the above embodiment, the antennas 30, 130 and the EBG structure 20 were shown to be positioned near the corners of the roof glass 14 or windshield 16. However, the position of the EBG structure is not limited to this embodiment, and it may be provided, for example, near the center in the width direction of the vehicle.

[0127] In the above embodiment, the antennas 30, 130 and the EBG structure 20 were shown to be provided on the roof glass 14 or the windshield 16. However, the antennas and EBG structure are not limited to this embodiment and may be provided on the rear glass 18 or the side glass, for example, as shown in Figure 1.

[0128] In the above embodiment, the roof glass 14 and windshield 16 were shown to be formed in a substantially rectangular plate shape. However, the roof glass and windshield are not limited to this embodiment and may be in other shapes.

[0129] In the above embodiment, an example was shown in which the radio wave transmission and reception area 30A is formed in a rectangular shape. However, the radio wave transmission and reception area is not limited to this embodiment and may be polygonal, circular, or other shapes, for example.

[0130] In the above embodiment, the metal frame 12 is positioned around the periphery of the roof glass 14 and the windshield 16 and is shown to be formed in a substantially rectangular frame shape. However, the metal frame may have a portion of the substantially rectangular frame shape cut out.

[0131] In the above embodiment, an example was shown in which antenna 30 is a GNSS antenna and antenna 130 is a V2X antenna. However, the antenna can be applied to various types of antennas, such as antennas for receiving broadcast waves, antennas for ITS, and 1.2GHz band antennas.

[0132] In the above embodiment, an example was shown in which the glass plates 4, 6, 106, 206 with EBG structures and the vehicle antenna devices 4A, 6A, 106A, 206A are applied to the roof glass 14 or windshield 16. However, the glass plates with EBG structures and the vehicle antenna devices are not limited to this embodiment and may be applied to, for example, the rear glass 18.

[0133] In the above embodiment, an example was shown in which the EBG structure-equipped glass plates 4, 6, 106, 206 and the vehicle antenna device are applied to a vehicle 10 equipped with a roof glass 14. However, the EBG structure-equipped glass plates and the vehicle antenna device may also be applied to a vehicle that does not have a roof glass. The disclosure of Japanese Patent Application No. 2021-213430, filed on 27 December 2021, is incorporated herein by reference in its entirety. [Explanation of symbols]

[0134] 4. Glass plate with EBG structure 4A Vehicle Antenna Device 10 vehicles 12 Metal Frame 14. Roof glass (an example of a glass panel) 20 EBG structure 30A Radio wave transmission and reception area 36C radiation surface 16. Windshield (an example of a glass panel) 16-1 First Glass Plate 16-2 Second Glass Plate 17 Interlayer

Claims

1. A glass panel for vehicles that is attached to the metal frame of the vehicle body, An EBG structure is formed in a frame shape by periodically arranging a predetermined conductive pattern, which is a unit pattern formed by the conductive portion, on the main surface of the glass plate, It has a radio wave transmission and reception area surrounded by the aforementioned EBG structure, The conductor portion of the conductor pattern includes a main patch formed in a plate shape and positioned approximately in the center of the conductor pattern, sub-patches formed in a plate shape and provided around the main patch, with a portion connected to the main patch, and bridge portions formed in a plate shape, extending from the main patch and connecting adjacent main patches. Glass plate with EBG structure.

2. Viewed from the thickness direction of the glass plate, the shortest distance from the outer edge of the EBG structure to any one of the edges of the glass plate is longer than the longest distance from the centroid of the radio wave transmission / reception area to the outer edge of the radio wave transmission / reception area. Glass plate with EBG structure according to claim 1.

3. The aforementioned radio wave transmission and reception area is rectangular in shape when viewed from the thickness direction of the glass plate. Glass plate with EBG structure according to claim 1 or claim 2.

4. The shortest distance from the first edge forming the outer edge of the glass plate to the outer edge of the EBG structure is different from the shortest distance from the second edge forming the outer edge of the glass plate to the outer edge of the EBG structure. Glass plate with EBG structure according to claim 1 or claim 2.

5. The EBG structure is positioned near the corner of the glass plate. Glass plate with EBG structure according to claim 1 or claim 2.

6. The EBG structure has the conductor pattern arranged in two or more parallel rows between the radio wave transmitting / receiving area and the metal frame. Glass plate with EBG structure according to claim 1 or claim 2.

7. The EBG structure has a planar shape and is arranged on the main surface of the glass plate. Glass plate with EBG structure according to claim 1 or claim 2.

8. The glass plate is a laminated glass having a first glass plate, a second glass plate, and an interlayer interposed between the first glass plate and the second glass plate. The EBG structure is positioned between the first glass plate and the second glass plate. Glass plate with EBG structure according to claim 1 or claim 2.

9. The glass plate is a laminated glass having a first glass plate, a second glass plate, and an interlayer interposed between the first glass plate and the second glass plate. The EBG structure is positioned on the main surface of the second glass plate opposite to the first glass plate side. Glass plate with EBG structure according to claim 1 or claim 2.

10. A glass plate with an EBG structure according to claim 1 or claim 2, The antenna comprises an antenna having a radiating surface positioned opposite the radio wave transmission and reception area. Vehicle antenna device.

11. The radiating surface is spaced apart from the glass plate. The vehicle antenna device according to claim 10.

12. The aforementioned antenna is a satellite communication antenna. The vehicle antenna device according to claim 10.

13. The aforementioned antenna is a GNSS antenna. The vehicle antenna device according to claim 12.

14. The aforementioned radiating surface is arranged substantially parallel to the horizontal plane. The vehicle antenna device according to claim 12.

15. The aforementioned glass panel is a roof glass, windshield, or rear glass. The vehicle antenna device according to claim 10.

16. The aforementioned radiating surface is arranged substantially parallel to the vertical direction. The vehicle antenna device according to claim 10.

17. The aforementioned glass plate is a windshield, rear window, or side window. The aforementioned antenna is a V2X antenna. The vehicle antenna device according to claim 16.

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