Vehicle antenna device

Abstract

[Problem] To prevent worsening of antenna gain in a prescribed direction of a communication antenna which is provided to a vehicle window glass so as to be spaced apart in a vehicle width direction from an electronic device provided to a center section in the vehicle width direction at or near an upper portion of the vehicle window glass. [Solution] The present invention comprises: a vehicle window glass 28, 34 that can be attached to a vehicle 10 so as to constitute a windshield and / or a rear glass; an electronic device 32 that is provided near a center section in the vehicle width direction at or near an upper portion in a vehicle up-down direction of the vehicle window glass; and an antenna 50 that is attached to the upper portion of the vehicle window glass so that a normal line of a radiation plane passes through a principal surface. A central position CP2 in the vehicle width direction of the antenna is spaced apart from a reference position CP1 which is at the center in the vehicle width direction of the electronic device. The radiation plane is tilted so that, when viewed in the vehicle up-down direction, a second end 50E2, which is the end on the side opposite the reference position side of the radiation plane, is positioned more toward a lower edge side of the vehicle window glass than a first end 50E1, which is the end on the reference position side.

Description

Technical Field

[0001] The present disclosure relates to a vehicle antenna device.

Background Art

[0002] In recent years, various electronic devices may be fixed by brackets and installed inside a vehicle cabin at the upper part of a vehicle windshield. These electronic devices include, for example, sensors including a visible light camera and a millimeter wave radar.

[0003] Furthermore, in recent years, with the evolution of vehicle driving support control, attempts have been made to perform high-speed and large-capacity communication using radio waves in a high-frequency band including the GHz band. In particular, as the level of autonomous driving improves, as a fifth-generation mobile communication system (5G) using a frequency band of GHz, a communication system using V2X (Vehicle to Everything) such as vehicle-to-vehicle communication and road-vehicle communication is being realized. In the V2X communication system, a communication antenna for V2X is installed in a vehicle, and this may be arranged near the windshield inside the vehicle cabin (see International Publication No. 2019 / 208453). In this case, both the above-mentioned electronic device and the communication antenna may be attached to the upper side portion of the windshield.

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, when arranging the communication antenna and the electronic device near the windshield with a short distance between them, there is a possibility of radio wave interference between the communication antenna and the electronic device. Also, when arranging the communication antenna and the electronic device with a long vertical distance on the windshield so as not to cause interference, there is a possibility that the communication antenna or the electronic device may obstruct the driver's field of view. Therefore, in order to solve these problems, it is necessary to arrange both of them near the windshield while maintaining a certain interval in the vehicle width direction between the communication antenna and the electronic device.

[0005] However, in-vehicle units equipped with electronic devices such as image sensors, fixed by brackets and covered by cover members, are typically mounted in the center of the vehicle's width, above the windshield inside the vehicle. Therefore, if the communication antenna is spaced a predetermined distance away from the electronic devices in the vehicle's width direction, the communication antenna will be positioned biased to one side in the vehicle's width direction relative to the center of the vehicle's width. In this case, the antenna gain in the predetermined direction for radio waves in the frequency band transmitted and received by the communication antenna tends to decrease, making it difficult to obtain the desired directivity.

[0006] This disclosure, taking the above facts into consideration, aims to provide a vehicle antenna device that can suppress the reduction in antenna gain in a predetermined direction and has excellent directivity, for a communication antenna provided on a vehicle window so as to be away in the vehicle width direction from electronic equipment provided in the upper part of the vehicle window or the central part in the vehicle width direction near the upper part of the vehicle window. [Means for solving the problem]

[0007] The vehicle antenna device according to this disclosure includes a vehicle window glass that can be attached to a vehicle so as to constitute at least one of the windshield and the rear window, an electronic device provided on the upper part of the vehicle window glass in the vertical direction of the vehicle or in the center in the vehicle width direction near the upper part when the vehicle window glass is attached to the vehicle, and a radiator that transmits and receives radio waves in a predetermined frequency band. The vehicle window glass has a surface and is equipped with a radiating conductor mounted on the upper part of the main surface on the interior side of the vehicle window glass such that the normal of the radiating surface passes through the main surface, wherein the center position of the antenna in the vehicle width direction is a predetermined distance in the vehicle width direction from a reference position which is the center in the vehicle width direction of the electronic equipment provided in the upper part or the central part near the upper part of the vehicle window glass, and the radiating surface is inclined with respect to the vehicle width direction and the vehicle front-rear direction such that when the vehicle window glass mounted on the vehicle is viewed from the vehicle up-down direction, the second end, which is the end of the radiating surface opposite to the reference position side, is located on the lower edge side of the vehicle window glass than the first end, which is the end of the radiating surface on the reference position side. [Effects of the Invention]

[0008] The vehicle antenna device according to this disclosure makes it possible to suppress the reduction in antenna gain in a predetermined direction and provides excellent directivity for a communication antenna that is installed on a vehicle window so as to be away in the vehicle width direction from an electronic device installed in the upper part of the vehicle window or near the upper part in the center in the vehicle width direction. [Brief explanation of the drawing]

[0009] [Figure 1] This is a plan view from the vertical direction of a vehicle to which the vehicle antenna device according to the embodiment of this disclosure is applied. [Figure 2] These are schematic side views of the front and rear of the vehicle, viewed along the arrow DRf in Figure 1, showing the roof, windshield, and rear window in cross-section. [Figure 3] This is a front view of the vehicle's antenna device and roof section. [Figure 4] This is a side view of a vehicle antenna device, showing a cross-sectional view of the windshield. [Figure 5] This is a perspective view of a portion of the vehicle's antenna system and the leading edge of the roof section. [Figure 6] This is a cross-sectional view of a vehicle antenna device along the line 6-6 in Figure 3. [Figure 7] This is a schematic plan view of a vehicle antenna device. [Figure 8] This figure shows the measurement results of the directivity of a vehicle antenna device in Example 1, where the distance WP is 200 mm and the inclination angle θH is 20°. [Figure 9] This figure shows the measurement results of the directivity of a vehicle antenna device in Example 2, where the distance WP is 200 mm and the inclination angle θH is 30°. [Figure 10] This figure shows the measurement results of the directivity of a vehicle antenna device in Example 3, where the distance WP is 200 mm and the inclination angle θH is 40°. [Figure 11] This figure shows the measurement results of the directivity of a vehicle antenna device in Example 4, where the distance WP is 200 mm and the inclination angle θH is 0°. [Figure 12] This figure shows the measurement results of the directivity of a vehicle antenna device in Example 5, where the distance WP is 360 mm and the inclination angle θH is 25°. [Figure 13] This figure shows the measurement results of the directivity of a vehicle antenna device in Example 6, where the distance WP is 360 mm and the inclination angle θH is 40°. [Figure 14] This figure shows the measurement results of the directivity of a vehicle antenna device in Example 7, where the distance WP is 360 mm and the inclination angle θH is 55°. [Figure 15] This figure shows the measurement results of the directivity of a vehicle antenna device in Example 8, where the distance WP is 360 mm and the inclination angle θH is 0°. [Modes for carrying out the invention]

[0010] The vehicle antenna device 40A according to the embodiment of this disclosure will be described below with reference to the attached drawings. In the following description, the vehicle antenna device 40A will be simply referred to as "antenna device 40A". As will be described later, the antenna device 40A of this embodiment is installed on a vehicle 10. The X-axis, as shown appropriately in each figure, is parallel to the vehicle width direction of the vehicle 10, the Y-axis is parallel to the vehicle's longitudinal direction, and the Z-axis is parallel to the vehicle's vertical direction and is also called the "vertical direction". Furthermore, arrow FR indicates the front in the vehicle's longitudinal direction, arrow UP indicates the upper in the vehicle's vertical direction, and arrow LF indicates the left in the vehicle width direction. The XY plane is a plane that passes through the X-axis and Y-axis and is also called the "horizontal plane". In other words, in the following description, the vehicle 10 is positioned on a horizontal plane, the vehicle's vertical direction coincides with its vertical direction, and the XY plane coincides with the horizontal plane, with the vertical direction corresponding to the normal direction to the horizontal plane. Furthermore, the XZ plane is a plane passing through the X and Z axes, and the YZ plane is a plane passing through the Y and Z axes.

[0011] As shown in Figure 1, the vehicle 10 according to this embodiment has a body 12 including a metal body. This metal body includes, for example, a roof portion 14, an A-pillar (front pillar) 16, and a C-pillar (rear pillar) 20. The roof portion 14 is the upper part of the vehicle body 12.

[0012] The upper ends (rear ends) of the pair of left and right A-pillars 16 are respectively connected to the front edge (flange) 14A of the roof portion 14. The left and right A-pillars 16 are inclined with respect to the Y-axis and Z-axis such that the lower ends are positioned forward of the upper ends in a side view (viewpoint from the X-axis direction) of the vehicle body 12. Further, the left and right A-pillars 16 are inclined with respect to the X-axis and Y-axis such that the lower ends (front ends) are positioned outside in the vehicle width direction of the upper ends (rear ends) in a viewpoint from the vertical direction (Z-axis direction).

[0013] The upper ends (front ends) of the pair of left and right C-pillars 20 are respectively connected to the rear edge (flange) 14B of the roof portion 14. The left and right C-pillars 20 are inclined with respect to the Y-axis and Z-axis such that the lower ends (rear ends) are positioned rearward of the upper ends (front ends) in a side view (viewpoint from the X-axis direction) of the vehicle body 12. Further, the left and right C-pillars 20 are inclined with respect to the X-axis and Y-axis such that the lower ends (rear ends) are positioned outside in the vehicle width direction of the upper ends (front ends) in a viewpoint from the vertical direction (Z-axis direction).

[0014] A substantially rectangular front opening 22 is formed in the front portion of the vehicle body 12. The upper edge portion of the front opening 22 is adjacent to the front edge portion 14A of the roof portion 14, and the left and right side edge portions of the front opening 22 are adjacent to the left and right A-pillars 16. A windshield (vehicle window glass) 28 is fitted in the front opening 22, and the peripheral portion of the windshield 28 is fixed to the peripheral portion of the front opening 22 with an adhesive such as urethane resin. As shown in FIGS. 2 and 4, the windshield 28 is inclined at an angle θ1 with respect to the XY plane 70 corresponding to the horizontal plane such that the lower end is positioned forward of the upper end in a side view. The windshield 28 is one of the components of the antenna device 40A.

[0015] At the rear of the vehicle body 12, a substantially rectangular rear opening 24 is formed. The upper edge of the rear opening 24 is adjacent to the rear edge 14B of the roof portion 14, and the left and right side edges of the rear opening 24 are adjacent to the left and right C-pillars 20. A rear glass (vehicle window glass) 34 is fitted into the rear opening 24, and the peripheral edge of the rear glass 34 is fixed to the peripheral edge of the rear opening 24 with an adhesive such as urethane resin. As shown in FIG. 2, the rear glass 34 is inclined at an angle θ2 with respect to the XY plane 70 corresponding to the horizontal plane such that the lower end portion is located behind the upper end portion in a side view. Note that the rear glass 34 is not limited to the example of being attached to the vehicle body 12 shown in FIG. 1, and may be attached to a back door made of resin having a metal reinforcement (not shown) so as to cover an opening formed in the back door.

[0016] As shown in FIGS. 1 and 2, a hollow box-shaped case 30 facing the main surface (rear surface) on the vehicle interior side of the windshield 28 is provided at the center in the vehicle width direction at the upper part in the vehicle vertical direction of the main surface. The case 30 may be directly attached to the main surface of the windshield 28 using an adhesive or the like, or may be attached using a bracket (not shown) for fixing the vehicle body 12 and the case 30. Further, a spacer fixed to the case 30 may be attached to the main surface of the windshield 28 using an adhesive or the like. One or more electronic devices 32 are housed inside the case 30. These electronic devices 32 include, for example, a visible light camera , a millimeter wave radar, and a rain sensor. Note that the electronic devices 32 only need to be fixed to the windshield 28 in the vehicle interior, and it is not necessary that the periphery of the electronic devices 32 be covered by the case 30.

[0017] Here, as shown in Figure 2, when the vehicle window glass (windshield 28, rear glass 34) is fixed to the vehicle 10, the vertical distance between the upper edge 28U and the lower edge 28D of the windshield 28, and the vertical distance between the upper edge 34U and the lower edge 34D of the rear glass 34 are defined as Lud. Furthermore, a predetermined portion in the vertical middle of the vehicle window glass is defined as Pm. Furthermore, when the vehicle window glass is fixed to the vehicle 10, the vertical distance between the upper edges 28U, 34U of the vehicle window glass and portion Pm is defined as Lm. When Lm / Lud = 0.3, the region between the upper edges 28U, 34U of the vehicle window glass and portion Pm corresponds to the "upper part of the vehicle window glass" according to this embodiment.

[0018] As shown in Figure 1, the reference position CP1 is defined as the center point of the electronic device 32 in the vehicle width direction when viewed from the vertical direction of the vehicle 10. The symbol CL shown in Figure 1 is the center line of the vehicle 10 that passes through the reference position CP1 in the Y-axis direction (vehicle travel direction) when viewed from above. Furthermore, in this specification, the "reference position of the electronic device 32" is assumed to coincide with the reference position CP1. However, even if the reference position, which is the center of the electronic device 32 in the vehicle width direction, does not perfectly coincide with the reference position CP1 from a vertical viewpoint and is slightly shifted in the vehicle width direction, in this specification, the reference position CP1 is considered to be the reference position of the electronic device 32.

[0019] Furthermore, in this specification, "an electronic device 32 is provided in the center of the vehicle width direction of the main surface on the interior side of the vehicle window glass (windshield 28, rear glass 34)" means that, from a vertical perspective, at least a part of the electronic device 32 (case 30) is located on the center line CL.

[0020] Furthermore, as shown in Figures 1 and 4, a communication antenna 50, which is one of the components of the antenna device 40A, is attached to the upper part of the main surface of the windshield 28 in the vehicle's vertical direction via a bracket or the like (not shown). The communication antenna 50 in this embodiment is, for example, a vertically polarized antenna, which has a higher antenna gain when transmitting and receiving vertically polarized waves compared to horizontally polarized waves. However, the communication antenna 50 may also be a horizontally polarized antenna, which has a higher antenna gain when transmitting and receiving horizontally polarized waves compared to vertically polarized waves, or an antenna whose vertical and horizontal polarized antenna gains are at the same level. The V2X antenna described below is an antenna that can transmit and receive using vertical polarization, and can utilize radio waves in the 5.8GHz band or the 5.9GHz band.

[0021] The greater the distance between the electronic device 32 and the antenna 50, the more interference between their radio waves can be suppressed and isolation can be ensured. In particular, the level of interference between the electronic device 32 and the antenna 50 changes depending on the shortest distance between the radio wave emitting parts. The shortest distance should be 50 mm or more, preferably 70 mm or more, more preferably 100 mm or more, even more preferably 150 mm or more, and especially preferably 180 mm or more. However, if this shortest distance is too far, it may obstruct the occupant's field of view over a wide area, so the shortest distance may be set appropriately as long as adequate isolation can be achieved. Note that if the shortest distance is too far, the antenna 50 will come close to the A-pillar 16, and the antenna gain of radio waves of a predetermined frequency may decrease due to the conductor of the A-pillar. For this reason, the distance of the antenna 50 from the A-pillar 16 should be 20 mm or more, preferably 30 mm or more, more preferably 50 mm or more, even more preferably 80 mm or more, and especially preferably 100 mm or more.

[0022] Next, the communication antenna 50 (hereinafter simply referred to as "antenna 50") of the vehicle antenna device 40A according to this embodiment will be described. As shown in Figures 3 to 7, The antenna 50 comprises a dielectric substrate 52, a conductive plate 54, a radiating plate (radiating conductor) 56, a feeding section 60, and a connecting conductor 62. As will be described later, the antenna 50 may also include a first element 66 and a second element 68. The antenna 50 in this embodiment is a patch antenna (microstrip antenna). The antenna 50 in this embodiment can be used, for example, as the above-mentioned V2X antenna, but the antenna 50 may be configured to transmit and receive radio waves in different frequency bands.

[0023] The dielectric substrate 52 is a plate-shaped or film-shaped dielectric layer mainly composed of a dielectric material. Here, "plate-shaped or film-shaped" may have a three-dimensional shape, including, for example, convex, concave, or wavy shapes. The same applies to the "plate-shaped or film-shaped" form of the conductor plate 54, radiating plate 56, first element 66, and second element 68. However, the conductor plate 54, radiating plate 56, first element 66, and second element 68 are preferably planar (two-dimensional) in shape. When these components are planar, it becomes easier to predict the antenna gain characteristics of the antenna 50. As is clear from Figures 5 and 6, the dielectric substrate 52 is a rectangular parallelepiped, and its front shape is a rectangle where the X-axis dimension is greater than the Z-axis dimension. However, the dielectric substrate 52 may also be a square with equal X-axis and Z-axis dimensions. The dielectric substrate 52 has a surface 52A, which is one surface in the thickness direction, and a surface 52B, which is the other surface. Surfaces 52A and 52B are planes parallel to each other. The dielectric substrate 52 may be made of, for example, a glass epoxy substrate or a dielectric sheet. The dielectric material included in the dielectric substrate 52 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 made of a material other than these.

[0024] A conductive plate 54 is provided on the surface 52A of the dielectric substrate 52. The conductive plate 54 functions as the ground for the antenna 50. The conductive plate 54 is a plate-shaped or film-shaped conductor. Both sides of the conductive plate 54 in the thickness direction are parallel to each other. Examples of materials that make up the conductive plate 54 include silver and copper, but materials other than silver and copper may also be used. The front shape of the conductive plate 54 shown is a square with a dimension in the X-axis direction smaller than that of the dielectric substrate 52. However, the front shape of the conductive plate 54 may be a shape other than a square. For example, the front shape of the conductive plate 54 may be a rectangle, a polygon, or a circle.

[0025] A radiating plate 56 is provided on the surface 52B of the dielectric substrate 52. The radiating plate 56 is a plate-shaped or film-shaped conductor, and its area is smaller than that of the conductor plate 54. The radiating plate 56 is a planar layer, and its front surface, the radiating surface 56C, is planar. As shown in Figure 2, the normal vector Dnf of the radiating surface 56C, which extends forward from the radiating surface 56C, passes through the windshield 28. Note that the normal vector Dnf in Figure 2 is the normal when the inclination angle α, which will be described later, is 0°. The radiating plate 56 functions as a radiating element of the antenna 50. Examples of materials that make up the radiating plate 56 include silver and copper, but materials other than silver and copper may also be used. The front shape of the illustrated radiating plate 56 is square. However, the front shape of the radiating plate 56 may be other than square. For example, the front shape of the radiating plate 56 may be polygonal or circular.

[0026] The power supply section 60 is a part that is supplied with power by contact or non-contact, and is a part to which one end of a power supply line (not shown in the figure) is connected or is adjacent. Specific examples of power supply lines include coaxial cables, microstrip lines, and coplanar power supply lines. The other end of the power supply line is connected to a communication device that communicates with the outside of the vehicle using the antenna 50.

[0027] In this embodiment, the connecting conductor 62 is provided inside a through-hole that penetrates the dielectric substrate 52, which is the medium between the conductor plate 54 and the radiating plate 56, in the direction of its plate thickness. The connecting conductor 62 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 62 is connected to the power supply unit 60, and the other end is connected to the connection point 56A of the radiating plate 56. One end of the connecting conductor 62 is not in contact with the conductor plate 54. As shown in Figure 3, in a front view, the connection point 56A is away from the centroid 56B of the radiating plate 56. Note that when the medium between the conductor plate 54 and the radiating plate 56 includes space (air), the connecting conductor 62 is, for example, the core wire or conductor pin of a coaxial cable, but the connecting conductor 62 in this case is not limited to these. As shown in Figure 6, the centroid 56B of the radiating plate 56 and the centroid 54A of the conductor plate 54 are located on a straight line PL that passes through the radiating plate 56 in its thickness direction. In this configuration, the antenna gain of the antenna 50 in the direction from the conductor plate 54 side to the radiating plate 56 side is improved.

[0028] As shown in Figures 3 and 7, the antenna 50 may further include at least one of a first element 66 and a second element 68, which are unpowered conductors. In this case, the first element 66 and the second element are spaced apart from each other in the vehicle width direction (horizontal direction) and are provided on the surface 52B of the dielectric substrate 52. However, at least one of the first element 66 and the second element 68 may be positioned away from the surface 52B of the dielectric substrate 52 on the Y-axis towards arrow FR, or away from the surface 52B on the opposite side of arrow FR. Also, when the antenna 50 is viewed along the thickness direction of the dielectric substrate 52, the radiating plate 56 is located between the first element 66 and the second element 68. Furthermore, as shown in Figure 7, when the antenna 50 is viewed along the Z-axis, the radiating plate 56 (its radiating surface 56C), the first element 66, and the second element 68 are located on the same plane.

[0029] Furthermore, as shown in Figure 2, the antenna 50 is arranged such that the normal vectors Dnef extending forward from the first element 66 and the second element 68 pass through the windshield 28. Note that the normal vector Dnef in Figure 2 is the normal when the inclination angle α, which will be described later, is 0°. Moreover, as shown in Figure 3, the first element 66 and the second element 68 of the antenna 50 are symmetrical with respect to the axis of symmetry SX passing through the connection point 56A in a front view, and the radiating plate 56 is symmetrical with respect to the axis of symmetry SX. When the first element 66 and the second element 68 are provided on the antenna 50 in this manner, the antenna gain of the antenna 50 in the vehicle width direction is improved. Note that when the first element 66 and the second element 68 are not provided, the antenna gain of the antenna 50 in the vehicle front-rear direction tends to be large, and the antenna gain of the antenna 50 in the vehicle width direction tends to be relatively small.

[0030] The areas of the first element 66 and the second element 68 may be smaller than the area of ​​the conductor plate 54 and also smaller than the area of ​​the radiating plate 56. However, the relative sizes of the areas of the first element 66, the second element 68, the conductor plate 54, and the radiating plate 56 are not limited to this. For example, if the antenna 50 can satisfy the desired directivity, the area of ​​at least one of the first element 66 and the second element 68 may be larger than the area of ​​the radiating plate 56.

[0031] Examples of materials that make up the first element 66 and the second element 68 include silver and copper, but materials other than silver and copper may also be used. In addition, although the front shape of the first element 66 and the second element 68 shown in the figure is rectangular, other shapes may also be used. For example, the front shape of the first element 66 and the second element 68 may be a square, a triangle, a polygon with pentagons or more sides, or a circle.

[0032] In particular, when at least one of the first element 66 and the second element 68 is included, the antenna gain of the antenna 50 (placed near the windshield) in the vehicle forward direction is appropriately distributed to the antenna gain in the vehicle width direction. Furthermore, when both the first element 66 and the second element 68 are included, the antenna 50 is more likely to obtain appropriate antenna gain in both the vehicle forward direction and the vehicle width direction.

[0033] In this specification, the 90° direction in the simulation results of the antenna gain of antenna 50 refers to the right side in the vehicle width direction (see Figure 1), and the 270° direction refers to the left side in the vehicle width direction. Yes. In this specification, the 0° direction in the simulation results of the antenna gain of antenna 50 refers to the front side (direction of travel) in the vehicle's longitudinal direction.

[0034] Here, we consider the case where the antenna 50 is configured such that the radiating surface 56C of the radiating plate 56, the first element 66, and the second element 68 are located on the same plane, as shown in Figure 7. Here, as shown in Figures 1 and 3, the right end of the antenna 50 when viewed in the Y-axis direction or the Z-axis direction is defined as the first end 50E1, and the left end of the antenna 50 is defined as the second end 50E2. That is, the right end of the first element 66 is defined as the first end 50E1, and the left end of the second element 68 is defined as the second end 50E2.

[0035] The antenna 50 is mounted on the upper part of the main surface on the interior side of the windshield 28 in the specific inclination state shown in Figure 1. Here, the specific inclination state of the antenna 50 is a state in which, from a viewpoint in the vertical direction (Z-axis direction) of the vehicle 10, the second end 50E2 is located closer to the lower edge of the windshield 28 than the first end 50E1. That is, the specific inclination state is an inclination state in which the radiating surface 56C of the radiating plate 56 (and the first element 66 and the second element 68) is inclined with respect to the X-axis and Y-axis directions. That is, the second end 50E2 of the antenna 50 in the specific inclination state is located further forward in the vehicle's longitudinal direction than the first end 50E1. Here, the angle (inclination angle) that the antenna 50 in the specific inclination state makes with the vehicle width direction (X-axis) in a plan view is defined as θH[°](0°<θH<90°). Furthermore, in order to improve the antenna gain of antenna 50, a range of 15°≦θH≦60° is preferred, and 20°≦θH≦55° is more preferred.

[0036] Furthermore, as shown in Figure 1, the distance in the vehicle width direction from the center line CL to the center position CP2 of the antenna 50 is defined as WP [mm]. Note that the symbol AL shown in Figure 1 is a virtual straight line that passes through the center position CP2 in the Y-axis direction from a viewpoint in the vertical direction. In this specification, the center position CP2 of the antenna 50 is the geometric center of the antenna 50, and corresponds to, for example, the centroid of the radiating plate 56. Furthermore, the vehicle width at the same longitudinal position as the center position CP2 of the vehicle 10 is defined as WA [mm]. In the vehicle 10 and antenna device 40A (windshield 28, antenna 50) of this embodiment, the following equation (1a) holds true. (WA / 2) × 0.2 ≤ WP ≤ (WA / 2) × 0.8 ... Equation (1a) For example, if WA = 1900 mm, antenna device 40A can be designed such that 100 mm ≤ WP ≤ 500 mm. However, WA = 1900 mm is just an example, and depending on the width of WA, WP may be less than 100 mm or greater than 500 mm.

[0037] Furthermore, in the vehicle 10 and antenna device 40A of this embodiment, it is preferable that the following equation (1b) holds, and it is even more preferable that equation (1c) holds. (WA / 2) × 0.2 ≤ WP ≤ (WA / 2) × 0.7 ... Equation (1b) (WA / 2) × 0.2 ≤ WP ≤ (WA / 2) × 0.6 ... Equation (1c)

[0038] Furthermore, in the vehicle 10 and antenna device 40A of this embodiment, the following equation (2a) holds between θH, WP, and WA. Note that in equation (2a), {WP / (WA / 2)×100} represents the relative position of the antenna 50 in the vehicle width direction with respect to the vehicle width WA of the vehicle 10. 0.50 ≤ θH / {(WP / (WA / 2)) × 100} ≤ 2.00 ... Equation (2a)

[0039] Furthermore, in the vehicle 10 and antenna device 40A of this embodiment, between θH, WP, and WA It is preferable that equation (2b) holds, more preferably that equation (2c) holds, even more preferably that equation (2d) holds, and particularly preferably that equation (2e) holds. 0.60 ≤ θH / {(WP / (WA / 2)) × 100} ≤ 1.95 ... Equation (2b) 0.65 ≤ θH / {(WP / (WA / 2)) × 100} ≤ 1.90 ... Equation (2c) 0.80 ≤ θH / {(WP / (WA / 2)) × 100} ≤ 1.50 ... Equation (2d) 0.85 ≤ θH / {(WP / (WA / 2)) × 100} ≤ 1.25 ... Equation (2e)

[0040] Next, the elevation and depression angles of the antenna 50 will be explained. As shown in Figure 2, when the front of the vehicle 10 is viewed from the left along the arrow DRf in Figure 1, it is preferable that the antenna 50 be installed such that the inclination angle α of the radiating surface 56C of the radiating plate 56 with respect to the vertical direction 71 is ±15° or less. Here, the arrow DRf in Figure 1 is parallel to the width direction of the antenna 50 in a plan view. Also, as shown by the solid line in Figure 2, when the radiating surface 56C is located behind the vertical direction 71, the value of the inclination angle α is + (positive). On the other hand, as shown by the dashed line in Figure 2, when the radiating surface 56C is located in front of the vertical direction 71, the value of the inclination angle α is - (negative). In other words, if the inclination angle α is greater than 0°, it is preferable that the elevation angle between the normal direction of the radiating surface 56C of the radiating plate 56 and the horizontal plane be greater than 0° and +15° or less. Furthermore, when the inclination angle α is less than 0°, it is desirable that the depression angle between the normal direction of the radiating surface 56C of the radiating plate 56 and the horizontal plane be less than 0° and greater than or equal to -15°. In this specification, the magnitude of the elevation angle is positive, and the magnitude of the depression angle is negative.

[0041] In particular, if the antenna 50 satisfies a predetermined directivity in the horizontal plane, and the elevation or depression angle of the radiating surface 56C becomes too large, the antenna gain in the horizontal plane will decrease. For example, if the antenna 50 is a V2X antenna, the efficiency of transmitting and receiving radio waves along the horizontal plane will decrease. Thus, if the inclination angle α of the radiating surface 56C of the radiating plate 56 exceeds ±15°, the balance of the antenna gain in the direction parallel to the XY plane 70 of the antenna 50 may be disrupted.

[0042] Furthermore, the inclination angle α of the radiating surface 56C of the radiating plate 56 of the antenna 50 is preferably ±10° or less, more preferably ±5° or less, even more preferably ±1° or less, and most preferably 0°. By reducing the absolute value of the inclination angle α in this way, the antenna gain along the horizontal plane can be improved.

[0043] Furthermore, it is necessary that no conductors such as the roof portion 14 are arranged in the forward and normal direction of the radiating surface 56C of the radiating plate 56 of the antenna 50. Moreover, when the elevation angle is φ[°] with respect to the forward and normal direction of the radiating surface 56C, it is desirable that no conductors (of the vehicle) are arranged in the range of φ from 0° to 20°, preferably no conductors are arranged in the range of 30°, and more preferably no conductors are arranged in the range of 45°. Similarly, in the case of a negative φ[°] (depression angle), it is desirable that no conductors (of the vehicle) are arranged in the range of φ from 0° to -20°, preferably no conductors are arranged in the range of -30°, and more preferably no conductors are arranged in the range of -45°. Note that an example of a conductor that may be arranged in the forward and normal direction of the radiating surface 56C when φ[°] is negative is a heating wire that extends vertically to heat the windshield and is arranged on the windshield at predetermined intervals in the vehicle width direction.

[0044] Next, Examples 1-3 and 5-7, which are embodiments of the above-described model, will be explained in comparison with comparative examples 4 and 8. Note that the dimensions of each part of the antenna 50 in Examples 1-8, and the distance between the antenna 50 and the surrounding members, are represented by reference numerals L20, L21, L50, L51, L53, L54, L55, L60, L61, L62, and L63 in Figures 3-5 and 7, respectively, as follows: As shown above. The unit of each dimension is mm. L55 is the distance in the Y-axis direction between the first element 66 and the second element 68 and the radiating surface 56C. L63 is the shortest distance between the antenna 50 and the metal body of the vehicle body 12. In this embodiment, L63 is the shortest distance between the upper edge of the conductor plate 54 and the front edge 14A of the roof portion 14. L20:19 L21:19 L50:18 L51:2 L53:22 L54:26 L55:0 L60:25 L61:24 L62:3 L63:35 Also, θ1: 22.5° WA: 1900mm WP: 200mm α:0° That is the case.

[0045] The values ​​of WP and θH for Examples 1-4 are as follows. <Example 1> WP: 200mm θH:20° <Example 2> WP: 200mm θH:30° <Example 3> WP: 200mm θH:40° <Example 4> WP: 200mm θH: 0°

[0046] Figures 8 to 11 show examples of measurement results for the directivity of antenna 50 in Examples 1 to 4. Each of these figures shows the simulation results of the antenna gain in each direction in the XY plane 70. 90° represents the right side in the vehicle width direction, 270° represents the left side in the vehicle width direction, 0° represents the front side in the vehicle longitudinal direction, and 180° represents the rear side in the vehicle longitudinal direction. The same applies to Figures 12 to 15, which will be described later.

[0047] As is clear from Figures 8 to 11, the antenna gain of antenna 50 in the range of 0° to +90° for Examples 1 to 3, where θH is greater than 0°, is better than the antenna gain of antenna 50 in Example 4, also in the range of 0° to +90°. In particular, in Figures 8 to 11, there is an area (null) near +75° where the amount of radio waves emitted is small, but in the comparative example Figure 11 (Example 4), the null is more pronounced than in Figures 8 to 10 (Examples 1 to 3: Embodiments), and the area that interferes with the transmission and reception of radio waves is particularly expanded.

[0048] The values ​​of WP and θH for Examples 5-7 and Example 8 are as follows. <Example 5> WP: 360mm θH:25° <Example 6> WP: 360mm θH:40° <Example 7> WP: 360mm θH: 55° <Example 8> WP: 360mm θH: 0°

[0049] Figures 12 to 15 show examples of the measurement results of the directivity of antenna 50 in Examples 5 to 8. As is clear from Figures 12 to 15, the antenna gain in the range of 0° to +90° for antenna 50 in Examples 5 to 7, where θH is greater than 0°, is better than the antenna gain in the range of 0° to +90° for antenna 50 in Example 8. In particular, in Figures 12 to 14 (Examples 5 to 7: Embodiments), there are no noticeable nulls in the range of 0° to +90°, but in the comparative example Figure 14 (Example 8), noticeable nulls are present near +60° and near +85°, confirming that these angles may interfere with the transmission and reception of radio waves.

[0050] As explained above, in the antenna device 40A of this embodiment, the antenna 50 is positioned to the left of the electronic device 32. In this case, when θH is set to 0°, the antenna gain on the right side of the antenna device 40A tends to decrease due to interference of radio waves between the electronic device 32 and the antenna device 40A. For example, an area with a small amount of radio wave radiation (null) is likely to occur in the range of 0° to +90°. However, as is clear from the measurement results of the directivity of the antenna 50 in Examples 1 to 3 and 5 to 7, when θH is greater than 0° under conditions where θH is less than 90°, the antenna gain of the antenna 50 in the range of 0° to ±90° is improved compared to the case where θH is 0°, regardless of the size of WP. That is, in this embodiment, nulls are less likely to occur in the range of 0° to +90°. In other words, according to this embodiment, it is possible to suppress the decrease in antenna gain in a predetermined direction of the antenna 50 provided on the windshield 28 so as to be away in the vehicle width direction from the electronic device 32 provided in the center of the upper part of the windshield 28 in the vehicle width direction.

[0051] Furthermore, if equation (1a) is satisfied, it is easier to suppress the decrease in antenna gain of antenna 50 in a predetermined direction compared to the case where equation (1a) is not satisfied. Furthermore, if equation (1b) is satisfied, it is easier to suppress the decrease in antenna gain of antenna 50 in a predetermined direction compared to the case where equation (1b) is not satisfied. Furthermore, if equation (1c) is satisfied, it is easier to suppress the decrease in antenna gain of antenna 50 in a predetermined direction compared to the case where equation (1c) is not satisfied.

[0052] Furthermore, if equation (2a) is satisfied, it is easier to suppress the decrease in antenna gain of antenna 50 in a predetermined direction compared to the case where equation (2a) is not satisfied. Furthermore, if equation (2b) is satisfied, it is easier to suppress the decrease in antenna gain of antenna 50 in a predetermined direction compared to the case where equation (2b) is not satisfied. Furthermore, if equation (2c) is satisfied, it is easier to suppress the decrease in antenna gain of antenna 50 in a predetermined direction compared to the case where equation (2c) is not satisfied. Furthermore, if equation (2d) is satisfied, it is easier to suppress the decrease in antenna gain of antenna 50 in a predetermined direction compared to the case where equation (2d) is not satisfied. Furthermore, if equation (2e) is satisfied, it is easier to suppress the decrease in antenna gain of antenna 50 in a predetermined direction compared to the case where equation (2e) is not satisfied.

[0053] Furthermore, in this embodiment, L is the shortest distance between the conductive plate 54 and the metal body of the vehicle body 12. The 63 is set to 20mm or more. Therefore, the transmission and reception of radio waves by antenna 50 is less likely to be interfered with by the metal body.

[0054] Furthermore, in this embodiment, there is only one antenna 50 provided on the windshield 28. Therefore, compared to the case where multiple antennas 50 are provided on the windshield 28, the area occupied by the antenna 50 in the vehicle interior space is smaller, and the field of view of the vehicle occupants is less likely to be obstructed by the antenna 50. Furthermore, compared to the case where multiple antennas 50 are provided on the windshield 28, the wiring structure and electrical circuit applied to the antenna 50 can be simplified. Moreover, for example, if the antenna 50 is a V2X antenna that transmits and receives vertically polarized waves in the 5.8GHz band or 5.9GHz band, good V2X communication can be achieved with a single antenna 50.

[0055] While embodiments of this disclosure have been described above, this disclosure is not limited to these embodiments.

[0056] For example, as shown in Figures 1 and 2, a case 30A containing one or more electronic devices 32A is provided in the center of the vehicle width direction at the top of the main surface (front) on the interior side of the rear window 34 in the vehicle width direction, and an antenna 50A located to the right of the case 30A may be mounted on the top of the main surface on the interior side of the rear window 34 in a specific inclined position. The case 30A has the same structure as the case 30, and the antenna 50A has the same structure as the antenna 50. In this case, the rear window 34 and the antenna 50A are components of the antenna device 40B.

[0057] However, in some vehicles, resin aero parts such as roof spoilers, rear spoilers, and tailgate spoilers may be provided so as to be away from the main surface of the rear glass 34, and the electronic equipment 32A may be attached to these aero parts. In this case, the electronic equipment 32A may not be provided on the upper part of the main surface of the rear glass 34 on the interior side of the vehicle, but rather away from the upper part of the main surface of the rear glass 34. That is, the electronic equipment 32A may be provided near the upper part of either one of the main surfaces of the rear glass 34. In this specification, "the electronic equipment 32A is provided near the upper part of either one of the main surfaces of the rear glass 34" means that the electronic equipment 32A is provided on the vehicle 10 such that the electronic equipment 32A and the upper part of either one of the main surfaces of the rear glass 34 are separated from each other by a distance of 200 mm or less. For example, if the electronic equipment 32A is provided on the tailgate spoiler, the electronic equipment 32A may also be provided near the upper part of the main surface of the rear glass 34 on the exterior side of the vehicle. Furthermore, even when the electronic device 32A is installed near the upper part of either the main surface of the rear glass 34, the electronic device 32A is installed in the center of the rear glass 34 in the vehicle width direction. That is, as shown in Figure 1, at least a part of the electronic device 32A (case 30A) is located on the center line CL when viewed from the vertical direction. Examples of electronic devices 32A installed near the upper part of the rear glass 34 include an antenna built into the spoiler, an image sensor such as a visible light camera, and a high-mounted stop lamp.

[0058] The specific inclination state of the antenna device 40B is an inclination state in which the radiating surface 56C, which is the rear surface of the radiating plate 56 (and the first element 66 and the second element 68), is inclined with respect to the X-axis and Y-axis directions such that, in a plan view, the second end 50E2 is located on the lower edge side of the rear glass 34 than the first end 50E1. That is, the second end 50E2 of the antenna 50A in the specific inclination state is located on the rear side in the vehicle's longitudinal direction than the first end 50E1. With respect to the inclination angle θH [°] made between the antenna 50A in the specific inclination state and the vehicle width direction (X-axis) in a plan view, the condition 0 < θH < 90 holds. In order to improve the antenna gain of the antenna 50A, 15 ≤ θH ≤ 60 is preferable. Furthermore, if 20 ≤ θH ≤ 55, the antenna gain of the antenna 50A is further improved. Thus, by making the θH of antenna 50A greater than 0° under conditions where θH is less than 90°, the antenna gain of antenna 50A in the horizontal plane in the range of 0° to ±90° is improved compared to the case where θH is 0°, regardless of the size of WP. In particular, the antenna gain in the range of 0° to ±60° is improved. Note that in this case, 90° refers to the left in the vehicle width direction. The angle indicates the side, with 270° representing the right side in the vehicle width direction, 0° representing the rear side in the vehicle's longitudinal direction, and 180° representing the front side in the vehicle's longitudinal direction. In this case, the measurement results of the directivity of antenna 50A are almost the same as those in Figures 8 to 10 and Figures 12 to 14.

[0059] In this case, as shown in Figure 2, when the rear of the vehicle 10 is viewed from the left along the arrow DRr in Figure 1, the inclination angle α of the radiating surface 56C of the radiating plate 56 of the antenna 50A with respect to the vertical direction 72 is preferably ±15° or less. An inclination angle α of ±10° or less is preferable. Furthermore, an inclination angle α of ±5° or less is more preferable, ±1° or less is even more preferable, and 0° is optimal.

[0060] When an antenna 50A is installed on the rear window 34 of the vehicle 10, an antenna 50 may or may not be installed on the windshield 28 of the vehicle 10. In the configuration shown in Figure 1, when an antenna 50 is installed on the windshield 28 and an antenna 50A is installed on the rear window 34, the desired antenna gain can be achieved in the range of 0° to 360° in the horizontal plane by the combined value of the antenna gains of antenna 50 and antenna 50A.

[0061] When mounting the case 30 and antenna 50 to the windshield 28, the center position CP2 of the antenna 50 may be located to the right of the reference position CP1 of the electronic equipment 32. Also, when mounting the electronic equipment 32A and antenna 50A to the rear glass 34, the center position CP2 of the antenna 50A may be located to the left of the reference position CP1 of the electronic equipment 32A.

[0062] If the center position CP2 of the antenna 50 is located to the left of the reference position CP1 of the electronic equipment 32, the right end of the antenna 50 and the left end of the electronic equipment 32 may be located on a straight line parallel to the center line CL in a plan view from the vertical direction. Similarly, if the center position CP2 of the antenna 50 is located to the right of the reference position CP1 of the electronic equipment 32, the left end of the antenna 50 and the right end of the electronic equipment 32 may be located on a straight line parallel to the center line CL in a plan view from the vertical direction. Furthermore, if the center position CP2 of the antenna 50A is located to the right of the reference position CP1 of the electronic equipment 32A, the left end of the antenna 50A and the right end of the electronic equipment 32A may be located on a straight line parallel to the center line CL in a plan view from the vertical direction. Similarly, if the center position CP2 of the antenna 50A is located to the left of the reference position CP1 of the bracket 30A, the right end of the antenna 50A and the left end of the electronic equipment 32A may be located on a straight line parallel to the center line CL in a plan view from the vertical direction.

[0063] The medium between the conductor plate 54 and the radiating plate 56 of antenna 50 and antenna 50A may include at least one of space (air) and a dielectric substrate. If the medium is space (air), the radiating plate 56, conductor plate 54, first element 66, and second element 68 may be fixed to the bracket (not shown).

[0064] Multiple antennas 50 may be attached to the windshield 28. Alternatively, multiple antennas 50A may be attached to the rear window 34.

[0065] At least one of antennas 50 and 50A may be a slot antenna. In this case, when viewing the vehicle window glass in the vertical direction of the vehicle, the planar radiating surface of the slot antenna is tilted with respect to the vehicle width direction and the vehicle front-rear direction.

[0066] At least one of the first element 66 and the second element 68 may be omitted from at least one of antenna 50 and antenna 50A.

[0067] A rear window 34 may be provided in a back door (not shown) that opens and closes an opening at the rear of the vehicle 10.

[0068] The disclosure of Japanese Patent Application No. 2021-159730, filed on 29 September 2021, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are incorporated by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually noted to be incorporated by reference. [Explanation of Symbols]

[0069] 10 vehicles 14. Roof section 28. Windshield (vehicle window glass) 32 Electronic equipment 34. Rear window (vehicle window glass) 40A 40B Vehicle Antenna System (Antenna System) 50 50A (communication) antenna (patch antenna) 50E1 1st end 50E2 2nd end 56 Radiating plate (radiating conductor) 56C Radiation surface 66. First Element 68. Second Element 70 XY plane (horizontal plane) CL center line CP1 Reference position CP2 center position WA Vehicle width WP distance Inclination angle θH

Claims

1. A vehicle window glass that can be mounted on a vehicle to constitute at least one of the windshield and the rear window, When the vehicle window glass is installed in the vehicle, an electronic device is provided in the upper part of the vehicle window glass in the vertical direction of the vehicle or in the central part in the vehicle width direction near the upper part, An antenna having a radiating surface for transmitting and receiving radio waves in a predetermined frequency band, and a radiating conductor attached to the upper part of the main surface on the interior side of the vehicle window glass such that the normal to the radiating surface passes through the main surface, Equipped with, The center position of the antenna in the vehicle width direction is separated by a predetermined distance in the vehicle width direction from a reference position which is the center in the vehicle width direction of the electronic device provided in the upper part or the central part near the upper part of the vehicle window glass, When the vehicle window glass installed in the vehicle is viewed from the top and bottom of the vehicle, the radiating surface is inclined with respect to the vehicle width direction and the vehicle longitudinal direction such that the second end, which is the end of the radiating surface opposite to the reference position, is located on the lower edge side of the vehicle window glass, compared to the first end, which is the end of the radiating surface on the reference position side. The position of a part of the electronic device in the vehicle width direction coincides with the center line that passes through the center of the vehicle width direction in the vehicle longitudinal direction. When the width of the vehicle at the aforementioned center position is WA [mm], and the distance in the vehicle width direction from the center line to the aforementioned center position of the antenna is WP [mm], (WA / 2) × 0.2 ≤ WP ≤ (WA / 2) × 0.8 Satisfied, When the angle between the antenna and the vehicle width direction is defined as θH [°], 0.50≦θH / {(WP / (WA / 2))×100}≦2.00 A vehicle antenna device that satisfies the following requirements.

2. The vehicle antenna device according to claim 1, wherein the electronic device is attached to the main surface on the interior side of the vehicle.

3. The vehicle antenna device according to claim 1, wherein the angle θH [°] is between 15° and 60°.

4. The vehicle antenna device according to claim 1 or 3, wherein the distance WP [mm] is 100 mm to 500 mm.

5. The vehicle antenna device according to claim 1 or 2, wherein the shortest distance between the antenna and the metal body of the vehicle is 20 mm or more.

6. The vehicle antenna device according to claim 1 or 2, wherein the shortest distance between the part of the electronic device that emits radio waves and the part of the antenna that emits radio waves is 50 mm or more.

7. The vehicle antenna device according to claim 1 or 2, wherein the antenna is installed on the vehicle window glass such that, when the vehicle is viewed along the width direction of the antenna, the angle between the radiating surface of the antenna and the vertical direction of the vehicle is within ±15°.

8. Only one of the aforementioned vehicle window glass is provided with the aforementioned antenna, and the aforementioned antenna is The vehicle antenna device according to claim 1 or 2, having only one radiating conductor connected to one power supply section via a connecting conductor.

9. The vehicle antenna device according to claim 1 or 2, wherein the antenna is a patch antenna.

10. The vehicle antenna device according to claim 1 or 2, wherein the antenna is capable of transmitting and receiving radio waves in the 5.8 GHz band or the 5.9 GHz band.

11. The vehicle antenna device according to claim 1 or 2, wherein the vehicle window glass includes the windshield and the rear glass.

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