Antenna device and method for mounting antenna device

Abstract

The antenna device has an antenna that radiates radio waves from the other side in a predetermined direction toward a radio wave transmitting body that has both end portions located on opposite sides from each other, and is inclined at a predetermined angle with respect to the predetermined direction between the both end portions as the antenna extends from one side in the predetermined direction toward the other side. A portion of the radio wave penetrating body that overlaps an image projected by the antenna in the predetermined direction is located at a position shifted toward a side where the one of the end portions of the radio wave penetrating body is located with respect to a center portion between the end portions of the radio wave penetrating body.

Description

Technical Field

[0001] The present invention relates to an antenna device and a method for mounting the antenna device. Background Art

[0002] In recent years, various V2X (Vehicle-to-Everything) antennas have been developed. In one example, a V2X antenna comprises a square radiating element and a passive element, arranged outside two opposing sides of the radiating element and extending along the two opposing sides. For example, as described in Patent Document 1, a V2X antenna is placed on at least one of the front or rear windshield of a vehicle, such as an automobile. Prior art literature Patent Literature

[0003] Patent Document 1: International Publication No. 2019 / 073667 Summary of the Invention

[0004] Some communications, such as V2X communications, require stable communication regardless of the vehicle's front, rear, left, or right orientation. That is, antenna systems for some communications, such as V2X communications, require non-directionality. As described in Patent Document 1, antennas are sometimes placed on the front and rear windshields. However, even if antennas are placed on the front and rear windshields, it is sometimes difficult to obtain sufficient gain in the left and right directions of the vehicle. That is, even if antennas are placed on the front and rear windshields, it is sometimes difficult to ensure directivity over a large area around the vehicle. In order to ensure directivity over a large area, antennas are sometimes added to the left and right sides of the vehicle. However, if antennas are added to the left and right sides of the vehicle, it is also necessary to add antennas and processing units, which increases costs.

[0005] One object of the present invention is to ensure directivity over a wide range using a small number of antennas. Other objects of the present invention will become apparent from the description of this specification.

[0006] One embodiment of the present invention is an antenna device, wherein: An antenna radiates radio waves from the other side of a predetermined direction toward a radio wave penetrating body, wherein the radio wave penetrating body has two end portions located on opposite sides of each other, and is inclined at a predetermined angle relative to the predetermined direction between the two end portions as it moves from one side in the predetermined direction toward the other side. The portion of the radio wave penetrating body that overlaps with the image projected by the antenna in the prescribed direction is located at a position offset toward the side where the end portion of one of the two end portions of the radio wave penetrating body is located, relative to the central portion between the two end portions of the radio wave penetrating body.

[0007] One embodiment of the present invention is a method for mounting an antenna device, wherein: An antenna that radiates radio waves from the other side in a predetermined direction toward a radio wave penetrating body is positioned, wherein the radio wave penetrating body has two end portions located on opposite sides of each other and is inclined at a predetermined angle relative to the predetermined direction between the two end portions as it moves from one side in the predetermined direction toward the other side. The portion of the radio wave penetrating body that overlaps with the image projected by the antenna in the prescribed direction is located at a position offset toward the side where the end portion of one of the two end portions of the radio wave penetrating body is located, relative to the central portion between the two end portions of the radio wave penetrating body.

[0008] According to the above aspect of the present invention, directivity can be ensured over a wide range using a small number of antennas. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1A It is a plan view of a vehicle equipped with the antenna device according to the embodiment. Figure 1B This is a diagram showing a front windshield of a vehicle equipped with the antenna device according to the embodiment and its surroundings as viewed from the left side of the vehicle. Figure 1C This is a diagram showing a rear windshield and its surroundings of a vehicle equipped with the antenna device according to the embodiment, as viewed from the left side of the vehicle. Figure 2 It is a perspective view showing a configuration example of a front antenna according to an embodiment. Figure 3A 1 is a horizontal plane directivity gain pattern of the antenna device according to the first embodiment when mounted on a vehicle. Figure 3B 1 is a horizontal plane directivity gain pattern of the antenna device of the comparative example when mounted on a vehicle. Figure 4 It is a plan view of a vehicle equipped with an antenna device according to a comparative example. Figure 5A This is the directivity gain pattern in the horizontal plane when the front antenna overlaps the upper end, center, or lower end of the front windshield in the front-rear direction of the vehicle. Figure 5B This is the directivity gain pattern in the vertical plane when the front antenna overlaps the upper end, center, or lower end of the front windshield in the front-rear direction of the vehicle. Figure 6A This is a diagram showing a partial configuration of a vehicle in which a leading body is provided below and in front of a front antenna. Figure 6B This is a diagram showing a partial configuration of a vehicle in which no leading body is provided below and in front of a front antenna. Figure 7A The figure shows the directivity gain pattern in the horizontal plane when a leading conductor is provided at the front lower portion of the front antenna and when it is not provided. Figure 7B The vertical plane directivity gain diagrams are shown for the case where a leading conductor is provided at the front lower portion of the front antenna and for the case where no leading conductor is provided. Figure 8 The diagrams show model examples in which the leading body has different angles with respect to the horizontal direction. Figure 9A It is the directivity gain diagram in the horizontal plane at different angles of the leading conductor relative to the horizontal direction. Figure 9B It is the vertical in-plane directivity gain diagram at different angles of the leading conductor relative to the horizontal direction. Figure 10A This is a diagram showing a first example of a back conductor according to the embodiment. Figure 10B This is a diagram showing a second example of the back conductor according to the embodiment. Figure 11 This diagram shows the black ceramic of the front windshield and the placement of the front antenna, viewed from the left side of the vehicle. Figure 12 This is a picture of the front antenna, front windshield, and black ceramic as viewed from the front of the vehicle. Figure 13 This is a diagram showing the arrangement of the front antenna and the front windshield as viewed from the left side of the vehicle. DETAILED DESCRIPTION

[0010] Hereinafter, the embodiment and modification of the present invention will be described using the drawings. In all the drawings, the same components are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

[0011] In this specification, approximate terms such as "substantially," "approximately," and "substantially" when used to modify the shape, position, or numerical value of an element mean that a person skilled in the art would understand that the intended purpose of the state is achieved. For example, "substantially parallel," depending on the context, includes not only a state of being completely parallel but also a state where the deviation from completely parallel is within a specified angular range.

[0012] To illustrate directions, the X, Y, and Z directions are defined. The Z direction is a direction parallel to the vertical direction. The X direction is a direction in the horizontal direction perpendicular to the Z direction. The Y direction is a direction in the horizontal direction perpendicular to both the Z and X directions. In the embodiments, the X direction is described as the front-to-back direction, the Y direction is described as the left-to-right direction, and the Z direction is described as the up-down direction. In the embodiments, the directions indicated by the arrows on the X-axis, Y-axis, and Z-axis are defined as the forward direction, the left direction, and the upward direction, respectively. Figure 1A、 Figure 1B 、 Figure 1C 、 Figure 4 、 Figure 6A 、 Figure 6B 、 Figure 8 、 Figure 10A 、 Figure 10B 、 Figure 11 、 Figure 12 as well as Figure 13 In the figure, a white circle with a black dot representing the X-axis, Y-axis or Z-axis indicates that the arrow indicated by the white circle points to the near side of the paper.

[0013] Figure 1A It is a plan view of a vehicle 50 equipped with the antenna device 1 according to the embodiment. Figure 1B This is a diagram showing a front windshield 510 of a vehicle 50 on which the antenna device 1 according to the embodiment is mounted and its surroundings as viewed from the left side of the vehicle 50 . Figure 1C This is a diagram showing a rear windshield 520 and its surroundings of a vehicle 50 on which the antenna device 1 according to the embodiment is mounted, as viewed from the left side of the vehicle 50 . Figure 1A The mounting position of the antenna device 1 of the embodiment on the vehicle 50 is shown. Figures 1A to 1C The matters described relate not only to the antenna device 1 according to the embodiment but also to a method of mounting the antenna device 1 according to the embodiment.

[0014] like Figure 1A As shown, the antenna device 1 of the embodiment includes a front antenna 10A and a rear antenna 10B. Thus, the front antenna 10A ensures directivity in front of the vehicle 50 and on both sides in the left and right directions, while the rear antenna 10B ensures directivity in the rear of the vehicle 50 and on both sides in the left and right directions. The front antenna 10A and the rear antenna 10B are located on opposite sides of each other in the X direction. Therefore, the antenna device 1 can have omnidirectional directivity using the front antenna 10A and the rear antenna 10B. In other words, compared to the case where only one of the front antenna 10A and the rear antenna 10B is used, directivity can be ensured over a wider range. However, the antenna device 1 does not need to include both the front antenna 10A and the rear antenna 10B, but may include only one of the front antenna 10A and the rear antenna 10B. Alternatively, the antenna device 1 may include an additional antenna corresponding to the front antenna 10A or the rear antenna 10B in addition to at least one of the front antenna 10A and the rear antenna 10B. Additional antennas can be installed on vehicle glass other than the front windshield 510 and rear windshield 520, such as side windows and rear quarter windows, or on components of vehicle 50 such as spoilers, bumpers, pillars, and roof 502. The glass on which the additional antenna is installed serves as a dielectric material, such as a radio wave or light-transmitting material. Additional antennas are installed to ensure the design of vehicle 50 and to avoid obstructing vision from within the vehicle 50.

[0015] The front antenna 10A and the rear antenna 10B of the embodiment are V2X (Vehicle-to-Everything) antennas. However, the front antenna 10A and the rear antenna 10B may be other antennas such as DSRC (Dedicated Short Range Communications), ETC (Electronic Toll Collection), WiFi (registered trademark), Bluetooth (registered trademark), GNSS (Global Navigation Satellite System), 5G (5th Generation Mobile Communication System), LTE (Long Term Evolution), etc. At least one of the transmission and reception of radio waves by the front antenna 10A is performed, for example, by using a Figure 2 The antenna element covered by the front antenna housing 110A described above performs transmission and reception of radio waves by the rear antenna 10B in the same manner.

[0016] In the embodiment, the front antenna 10A and the rear antenna 10B are identical antennas. Therefore, the directional characteristics, half-value angle, corresponding frequencies, and corresponding media of the front antenna 10A are identical to those of the rear antenna 10B. However, the directional characteristics, half-value angle, corresponding frequencies, and corresponding media of the front antenna 10A and the directional characteristics, half-value angle, corresponding frequencies, and corresponding media of the rear antenna 10B may differ.

[0017] Figure 1A 、 Figure 1B as well as Figure 1C In the figure, the front antenna 10A and the rear antenna 10B are schematically shown as a substantially rectangular parallelepiped antenna housing that houses an antenna element such as a patch antenna. In the following figures, unless otherwise specified, the front antenna 10A and the rear antenna 10B are schematically shown as a substantially rectangular parallelepiped antenna housing. The substantially rectangular parallelepiped antenna housings of the front antenna 10A and the rear antenna 10B are, for example, used in conjunction with the antenna described later. Figure 2 The front antenna housing 110A described above has the same configuration.

[0018] The vehicle 50 in the embodiment is a sedan-type motor vehicle. However, the vehicle 50 may be any type of motor vehicle. For example, the vehicle 50 may be a non-sedan type motor vehicle, such as a van or an SUV (Sport Utility Vehicle). Unless otherwise specified, the vehicle 50 in the embodiment will be described as a sedan-type motor vehicle.

[0019] like Figure 1AAs shown, the vehicle 50 of the embodiment includes a body 500, a front windshield 510, and a rear windshield 520. The body 500 includes a roof 502, a hood 504, and a trunk lid 506. The roof 502 is not particularly limited, but may be, for example, a steel roof, a glass roof, a resin roof, a carbon fiber roof, or a combination of these. The hood 504 and the trunk lid 506 are conductive sheet metal made of, for example, aluminum, steel, or the like. However, portions of the hood 504 and the trunk lid 506 may also be made of resin. A hatchback may be used in place of the trunk lid 506. When viewed in the Z direction, the roof 502 is located approximately in the center of the body 500 in the X direction. When viewed in the Z direction, the hood 504 is located at the front portion of the body 500 in the X direction. When viewed in the Z direction, the front windshield 510 is located between the front end of the roof 502 and the rear end of the hood 504 in the X direction. The front windshield 510 is a dielectric. Specifically, the front windshield 510 is a radio wave transmitting member that allows radio waves to pass between the interior of the vehicle 50 and the space in front of the vehicle 50. Furthermore, the front windshield 510 is a light transmitting member that allows visible light and other light to pass between the interior of the vehicle 50 and the space in front of the vehicle 50. When viewed from the Z direction, the trunk lid 506 is located at the rear portion of the vehicle body 500 in the X direction. When viewed from the Z direction, the rear windshield 520 is located between the rear end of the roof 502 and the front end of the trunk lid 506 in the X direction. The rear windshield 520 is a dielectric. Specifically, the rear windshield 520 is a radio wave transmitting member that allows radio waves to pass between the interior of the vehicle 50 and the space behind the vehicle 50. Furthermore, the rear windshield 520 is a light transmitting member that allows visible light and other light to pass between the interior of the vehicle 50 and the space behind the vehicle 50.

[0020] like Figure 1B As shown, the front antenna 10A is arranged in a state where a radiation surface of the front antenna 10A that radiates radio waves faces the front of the vehicle 50 . Figure 1BIn the example shown, the radiating surface of front antenna 10A is the front surface of front antenna 10A. The antenna type of front antenna 10A is not particularly limited. For example, front antenna 10A can be a patch antenna, a dipole antenna, or any other type of antenna. The front windshield 510 is positioned in front of the radiating surface of front antenna 10A. That is, front antenna 10A is positioned rearward relative to front windshield 510. Thus, front antenna 10A is positioned inside the vehicle interior relative to front windshield 510. Therefore, front antenna 10A radiates radio waves toward front windshield 510. The hood 504 is located below and in front of front antenna 10A. In one example, front antenna 10A is fixed to the rear surface of front windshield 510. The rear surface of front windshield 510 is the surface of front windshield 510 facing the vehicle interior. In other examples, front antenna 10A can also be positioned above or inside the instrument panel between the lower end of front windshield 510 and the rear end of hood 504. The front antenna 10A may be disposed in a state covered with a resin cover together with other electrical components.

[0021] Hereinafter, as needed, the portion of the front windshield 510 that overlaps with the image projected in the X direction by the front antenna 10A is referred to as a front overlapping portion 510a. Figure 1B As shown, this image of the front antenna 10A is formed by projecting the substantially rectangular parallelepiped antenna housing of the front antenna 10A toward the front windshield 510 in parallel with respect to the X direction. Figure 1B In FIG. 1 , two dotted lines representing the front overlap portion 510a extend forward from the upper and lower surfaces of the front antenna 10A. The front overlap portion 510a is the portion of the front windshield 510 located between the two dotted lines. Figure 6A 、 Figure 6B 、 Figure 8 、 Figure 11 as well as Figure 13 The same is true for the front overlapping portion 510a shown.

[0022] like Figure 1A As shown, when viewed from the Z direction, the front overlapping portion 510a is located approximately in the left-right center of the front windshield 510. However, if other electrical components such as wipers, sensors, and a drive recorder, and black ceramic are located near the front antenna 10A, the front overlapping portion 510a may be located at a position offset in the Y direction from the approximately left-right center of the front windshield 510.

[0023] like Figure 1BAs shown, when viewed from the Y direction, the front windshield 510 is tilted at a predetermined angle relative to the X direction between the lower and upper ends of the front windshield 510. Specifically, when viewed from the Y direction, the front windshield 510 tilts upward as it moves from the rear end of the hood 504 toward the front end of the roof 502. Thus, when viewed from the Y direction, the lower end of the front windshield 510 is positioned forward relative to the upper end of the front windshield 510, while the upper end of the front windshield 510 is positioned rearward relative to the lower end of the front windshield 510. When viewed from the Y direction, the front overlapping portion 510a is positioned offset to one side of the lower end of the front windshield 510, relative to the center portion between the upper and lower ends of the front windshield 510. Specifically, the front overlapping portion 510a is located at the lower end of the front windshield 510. However, when wipers, sensors, other electrical components such as a drive recorder, and black ceramics are located near the front antenna 10A, the front overlapping portion 510a may be located appropriately offset from the lower end portion of the front windshield 510.

[0024] like Figure 1C As shown in FIG. 1 , the rear antenna 10B is arranged with the radiation surface of the rear antenna 10B for radiating radio waves facing the rear of the vehicle 50. Figure 1C In the example shown, the radiation surface of the rear antenna 10B is the rear surface of the rear antenna 10B. The antenna type of the rear antenna 10B is not particularly limited. For example, the rear antenna 10B can be a patch antenna and a dipole type antenna, or can be an antenna of any other type. The rear windshield 520 is arranged behind the radiation surface of the rear antenna 10B. That is, the rear antenna 10B is arranged on the front side relative to the rear windshield 520. Therefore, the rear antenna 10B is arranged on the inner side of the vehicle interior relative to the rear windshield 520. Therefore, the rear antenna 10B radiates radio waves toward the rear windshield 520. The trunk lid 506 is located at the rear and lower part of the rear antenna 10B. In one example, the rear antenna 10B is fixed to the front surface of the rear windshield 520. The front surface of the rear windshield 520 is the surface of the rear windshield 520 facing the inner side of the vehicle interior. In another example, the rear antenna 10B may be disposed above or inside a rear package tray located between the lower end of the rear windshield 520 and the front end of the trunk lid 506. The rear antenna 10B may also be disposed while being covered with a resin cover along with other electrical components.

[0025] Hereinafter, as needed, the portion of the rear windshield 520 that overlaps with the image projected in the X direction by the rear antenna 10B is referred to as a rear overlapping portion 520a. Figure 1C As shown, the image of the rear antenna 10B is formed by projecting the substantially rectangular parallelepiped antenna housing of the rear antenna 10B toward the rear windshield 520 in parallel with respect to the X direction. Figure 1C In FIG. 1 , two dotted lines representing the rear overlapping portion 520a extend from the upper and lower surfaces of the rear antenna 10B toward the rear. The rear overlapping portion 520a is the portion located between the two dotted lines of the rear windshield 520. Figure 10A as well as Figure 10B The same is true for the rear overlapping portion 520a shown.

[0026] like Figure 1A As shown, when viewed from the Z direction, the rear overlapping portion 520a is located approximately in the left-right center of the rear windshield 520. However, if other electrical components such as wipers, sensors, and a drive recorder, and black ceramic are located near the rear antenna 10B, the rear overlapping portion 520a may be located at a position offset in the Y direction from the approximately left-right center of the rear windshield 520.

[0027] like Figure 1C As shown, when viewed from the Y direction, the rear windshield 520 is tilted at a predetermined angle relative to the X direction between the lower and upper ends of the rear windshield 520. Specifically, when viewed from the Y direction, the rear windshield 520 tilts upward as it moves from the front end of the trunk lid 506 toward the rear end of the roof 502. Thus, when viewed from the Y direction, the lower end of the rear windshield 520 is positioned rearward relative to the upper end of the rear windshield 520, while the upper end of the rear windshield 520 is positioned forward relative to the lower end of the rear windshield 520. When viewed from the Y direction, the rear overlapping portion 520a is offset from the center portion between the upper and lower ends of the rear windshield 520, toward the side where the lower end of the rear windshield 520 is located. Specifically, the rear overlapping portion 520a is located at the lower end of the rear windshield 520. However, when other electrical components such as wipers, sensors, and a drive recorder, and black ceramics are located near the rear antenna 10B, the rear overlapping portion 520a may be located appropriately offset from the lower end portion of the rear windshield 520.

[0028] Figure 2 This is a perspective view showing a configuration example of the front antenna 10A according to the embodiment. Figure 2 The matters described for the front antenna 10A can also be applied to the rear antenna 10B. Figure 2 The configuration example shown.

[0029] like Figure 2 As shown, the front antenna 10A has a front antenna housing 110A and a front cable 120A.

[0030] The front antenna housing 110A is in the shape of a rectangular parallelepiped. Figure 2 The antenna element (not shown) is covered. This antenna element is, for example, a patch antenna. However, the antenna covered by front antenna housing 110A is not limited to a patch antenna. Front antenna housing 110A has radio wave permeability. Front antenna housing 110A is made of, for example, resin. Front antenna housing 110A is provided with a mounting structure. Front antenna housing 110A is secured to a mounting structure such as a bracket provided on vehicle 50 via this mounting structure.

[0031] Front cable 120A extends from front antenna housing 110A. Front cable 120A is electrically connected to the antenna element covered by front antenna housing 110A. Signals received from the antenna element covered by front antenna housing 110A are output via front cable 120A. However, the method for outputting signals from the antenna element is not limited to using front cable 120A. For example, a substrate such as a printed circuit board (PCB) carrying the antenna element and a connector such as a coaxial connector may be electrically connected. When the substrate and connector are electrically connected, the signals received from the antenna element are output via the substrate and connector.

[0032] Figure 3A 1 is a horizontal plane directivity gain pattern when the antenna device 1 according to the first embodiment is mounted on the vehicle 50 . Figure 3B 1 is a directivity gain pattern in a horizontal plane when the antenna device 1K of the comparative example is mounted on a vehicle 50 . Figure 4 1K is a plan view of a vehicle 50 equipped with an antenna device 1K of a comparative example. In the first embodiment and the comparative example, unless otherwise specified, a horizontal plane refers to a plane perpendicular to the Z direction.

[0033] The antenna device 1 of the first embodiment is an example of an antenna device 1 according to an embodiment. In the first embodiment, the front overlapping portion 510a is located at the lower end of the front windshield 510. In the first embodiment, the rear overlapping portion 520a is located at the lower end of the rear windshield 520. In the first embodiment, the front antenna 10A and the rear antenna 10B are identical antennas. That is, the half-value angle of the characteristic of the front antenna 10A and the half-value angle of the characteristic of the rear antenna 10B are the same.

[0034] Reference Figure 4 Next, an antenna device 1K according to a comparative example will be described. The antenna device 1K according to the comparative example is similar to the antenna device 1 according to the first embodiment except for the following points.

[0035] The front antenna 10A of the first embodiment and the front antenna 10A of the comparative embodiment are identical. When viewed from the Z direction, the front overlapping portion 510aK of the comparative embodiment is located in the center of the front windshield 510 in the left-right direction, similar to the front overlapping portion 510a of the first embodiment. When viewed from the Y direction, the front overlapping portion 510aK of the comparative embodiment, unlike the front overlapping portion 510a of the first embodiment, is located in the center between the upper and lower ends of the front windshield 510.

[0036] The rear antenna 10B of the first embodiment and the rear antenna 10B of the comparative example are identical. When viewed from the Z direction, the rear overlapping portion 520aK of the comparative example, like the rear overlapping portion 520a of the first embodiment, is located in the center of the rear windshield 520 in the left-right direction. Unlike the rear overlapping portion 520a of the first embodiment, the rear overlapping portion 520aK of the comparative example is located in the center between the upper and lower ends of the rear windshield 520 when viewed from the Y direction.

[0037] Reference Figure 3A as well as Figure 3B The horizontal plane directivity gains of the antenna device 1 according to the first embodiment and the antenna device 1K according to the comparative example will be described.

[0038] exist Figure 3A as well as Figure 3B The numbers marked on the periphery of the gain graph indicate the direction (unit: °). Figure 3A as well as Figure 3B The number marked in the center of the gain graph towards 270° represents the gain (unit: dBi). Figure 3A as well as Figure 3B , the 0° direction is the front side of the vehicle 50 , the 180° direction is the rear side of the vehicle 50 , the 90° direction is the left side of the vehicle 50 , and the 270° direction is the right side of the vehicle 50 . Figure 3A The solid line pattern represents the horizontal plane directivity gain of the front antenna 10A according to the first embodiment. Figure 3A The dotted line pattern represents the horizontal plane directivity gain of the rear antenna 10B of the first embodiment. Figure 3B The solid line pattern represents the in-horizontal-plane directivity gain of the front antenna 10A of the comparative example. Figure 3B The dotted line pattern represents the horizontal plane directivity gain of the rear antenna 10B of the comparative example.

[0039] The 90° directional gain of the front antenna 10A of the first embodiment is -1.58 dBi. In contrast, the 90° directional gain of the front antenna 10A of the comparative example is -12.15 dBi. This shows that the 90° directional gain of the front antenna 10A of the first embodiment is significantly higher than that of the front antenna 10A of the comparative example. Therefore, even though the front antenna 10A of the first embodiment and the front antenna 10A of the comparative example are identical, changing the mounting position of the front antenna 10A can increase the half-value width of the front antenna 10A, thereby improving the gain of the front antenna 10A in the left-right direction of the vehicle 50.

[0040] The 90° directional gain of the rear antenna 10B of the first embodiment is -1.53 ​​dBi. In contrast, the 90° directional gain of the rear antenna 10B of the comparative example is -11.24 dBi. This shows that the 90° directional gain of the rear antenna 10B of the first embodiment is significantly higher than that of the rear antenna 10B of the comparative example. Therefore, even though the rear antenna 10B of the first embodiment and the rear antenna 10B of the comparative example are identical, changing the mounting position of the rear antenna 10B can increase the half-value width of the rear antenna 10B, thereby improving the gain of the rear antenna 10B in the left-right direction of the vehicle 50.

[0041] Figure 3A The difference between the maximum and minimum values ​​of the gain of the front antenna 10A in the range of 0° to 90° and 270° to less than 360° and the gain of the rear antenna 10B in the range of 90° to 270° is 8.21 dB. Figure 3B The difference between the maximum and minimum gain of the front antenna 10A in the range from 0° to 90° and from 270° to 360°, and the gain of the rear antenna 10B in the range from 90° to 270°, is 16.02 dB. Therefore, the first embodiment exhibits reduced ripple compared to the comparative example. Therefore, it can be seen that the antenna device 1 of the first embodiment maintains directivity over a wider range than the antenna device 1K of the comparative example. In particular, it can be said that the antenna device 1 of the first embodiment exhibits omnidirectional directivity.

[0042] In the first embodiment, the half-value angle of the characteristic of the front antenna 10A and the half-value angle of the rear antenna 10B are the same. However, the half-value angle of the characteristic of the front antenna 10A and the half-value angle of the rear antenna 10B may be different. If the half-value angle of the characteristic of the front antenna 10A and the half-value angle of the rear antenna 10B are different, for example, the half-value angles of the front antenna 10A and the rear antenna 10B can be determined so that the combined horizontal plane directional gain of the front antenna 10A and the rear antenna 10B has omnidirectional directivity.

[0043] Next, basic technical requirements of the antenna device 1 according to the embodiment and the first example will be described.

[0044] The radiation characteristics of front antenna 10A are described below when the front windshield 510 is located in front of the radiation surface of front antenna 10A. As the angle of incidence of the radio waves radiated from front antenna 10A on the rear surface of front windshield 510 approaches 0°, the radio waves radiated from front antenna 10A are less likely to be scattered on the rear surface of front windshield 510, making it easier for the radio waves to penetrate front windshield 510 and increasing the gain. In contrast, as the angle of incidence of the radio waves radiated from front antenna 10A on the rear surface of front windshield 510 approaches a right angle, the radio waves radiated from front antenna 10A are more likely to be scattered on the rear surface of front windshield 510, making it harder for the radio waves to penetrate front windshield 510 and decreasing the gain. In the comparative example, front antenna 10A overlaps the center portion between the upper and lower ends of front windshield 510 in the front-to-back direction of vehicle 50. In contrast, in the embodiment and the first example, the front antenna 10A partially overlaps the lower end of the front windshield 510 in the front-to-back direction of the vehicle 50. Consequently, the area of ​​the rear surface of the front windshield 510 illuminated by the radio waves radiated forward and downward from the front antenna 10A in the embodiment and the first example can be smaller than the area of ​​the rear surface of the front windshield 510 illuminated by the radio waves radiated forward and downward from the front antenna 10A in the comparative example. Consequently, the embodiment and the first example can suppress the scattering of the radio waves radiated forward and downward from the front antenna 10A on the rear surface of the front windshield 510 compared to the comparative example. Consequently, due to the suppressed scattering of radio waves on the rear surface of the front windshield 510, the gain of the embodiment and the first example can be higher than that of the comparative example.

[0045] Figure 5A This is the horizontal plane directivity gain pattern when the front antenna 10A overlaps the upper end portion, the center portion, or the lower end portion of the front windshield 510 in the front-rear direction of the vehicle 50. Figure 5A In the description of the front windshield 510, the central portion refers to the front windshield 510. Figure 1B The central portion between the upper end portion and the lower end portion of the front windshield 510 when viewed from the Y direction. Figure 5A , the 0° direction is the front side of the vehicle 50 , the 180° direction is the rear side of the vehicle 50 , the 90° direction is the left side of the vehicle 50 , and the 270° direction is the right side of the vehicle 50 . Figure 5A In FIG, the front windshield 510 is arranged on the 0° direction side of the front antenna 10A. Figure 5A The dotted line pattern, the dashed line pattern, and the solid line pattern respectively represent the horizontal plane directivity gain when the front antenna 10A overlaps the upper end portion, the central portion, and the lower end portion of the front windshield 510 in the X direction. Figure 5A In the data, the 90° directional gains when the front antenna 10A overlaps the upper, center, and lower portions of the front windshield 510 in the X direction are -11.99 dBi, -12.15 dBi, and -1.58 dBi, respectively. The 90° directional gains when the front antenna 10A overlaps the upper portion of the front windshield 510 in the X direction and when the front antenna 10A overlaps the center portion of the front windshield 510 in the X direction remain almost unchanged. In contrast, it can be seen that the directional gain in the left-right direction of the vehicle 50 increases as the front overlapping portion 510a approaches the lower end of the front windshield 510.

[0046] Figure 5B It is the directivity gain pattern in the vertical plane when the front antenna 10A overlaps the upper end portion, the center portion, or the lower end portion of the front windshield 510 in the front-back direction of the vehicle 50. Unless otherwise specified, Figure 5B In the description of the front windshield 510, the central portion refers to the front windshield 510. Figure 1B The central portion between the upper end portion and the lower end portion of the front windshield 510 when viewed from the Y direction. Figure 5B , the 90° direction is the front side of the vehicle 50 , the −90° direction is the rear side of the vehicle 50 , the 0° direction is the upper side of the vehicle 50 , and the 180° direction is the lower side of the vehicle 50 . Figure 5B In FIG, the front windshield 510 is arranged on the 90° direction side of the front antenna 10A. Figure 5B The dotted line pattern, the dashed line pattern, and the solid line pattern respectively represent the vertical in-plane directivity gains when the front antenna 10A overlaps the upper end portion, the central portion, and the lower end portion of the front windshield 510 in the X direction. Figure 5B As can be seen in the figure, the gain deviation (the difference between the maximum and minimum gain values) in the range of 60° to 120° decreases as the front overlapping portion 510a moves from the upper end of the windshield 510 toward the lower end. In other words, the gain of the front antenna 10A is higher when the front antenna 10A overlaps the lower end of the windshield 510 in the X direction than when the front antenna 10A overlaps the upper end of the windshield 510 in the X direction. This is because the area of ​​the rear surface of the windshield 510 illuminated by the radio waves radiated forward and downward from the front antenna 10A is smaller when the front antenna 10A overlaps the lower end of the windshield 510 in the X direction than when the front antenna 10A overlaps the upper end of the windshield 510 in the X direction, thereby suppressing the scattering of the radio waves on the rear surface of the windshield 510.

[0047] In the first embodiment, the front antenna 10A overlaps with the lower end of the front windshield 510 in the X direction. Thus, in the first embodiment, compared to a case where the front antenna 10A overlaps with the upper end or center of the front windshield 510 in the X direction, stable directivity can be maintained over a wide range. The wide-range directivity ensured in the first embodiment can be achieved without adding antennas to the left and right sides of the vehicle 50. Thus, in the first embodiment, directivity can be maintained over a wide range using a small number of antennas. The stable wide-range directivity ensured in the first embodiment is improved as the half-value angle of the front antenna 10A increases.

[0048] When viewed from the Y direction, the front overlapping portion 510a may be located in a portion that is not located at the lower end portion of the windshield 510 but is located at a predetermined distance forward of the center portion in the Z direction of the windshield 510. When the front overlapping portion 510a is located forward of the center portion in the Z direction of the windshield 510 when viewed from the Y direction, directivity can be ensured over a wide range with a smaller number of antennas, compared to a case where the front overlapping portion 510a is located at the center portion in the Z direction of the windshield 510 or at the upper end portion of the windshield 510 when viewed from the Y direction.

[0049] use Figure 3A 、 Figure 3B 、 Figure 4 、 Figure 5A as well as Figure 5B The matters described for the front antenna 10A can also be similarly applied to the rear antenna 10B.

[0050] Next, the characteristics of radio waves radiated from front antenna 10A or rear antenna 10B propagating within a conductor will be described. The embodiment and first example utilize the characteristics of radio waves radiated from front antenna 10A or rear antenna 10B propagating within conductive sheet metal, such as the hood 504 and trunk lid 506. The embodiment and first example utilize the characteristics of radio waves radiated from each antenna propagating within a conductor to ensure the gain of antenna device 1 in the left-right direction of vehicle 50. A hatchback door can also be used as a conductor for radio wave propagation, instead of trunk lid 506. Similar to trunk lid 506, the hatchback door can also be used for radio wave propagation.

[0051] Figure 6A 1 is a diagram showing a partial configuration of a vehicle 50 in which a front conductor 500a is provided at the front lower portion of a front antenna 10A. Figure 6B This figure shows a partial configuration of a vehicle 50 in which the front conductor 500a is not provided at the front lower portion of the front antenna 10A. Figure 6A as well as Figure 6B A comparative structure is shown with and without the front conductor 500 a at the front lower portion of the front antenna 10A. Figure 6A In the example shown, the engine cover 504 is the leading conductor 500a. Figure 6A In the example shown, when viewed from the Y direction, the leading conductor 500a is disposed forward relative to the lower end portion of the front windshield 510. Specifically, when viewed from the Y direction, the leading conductor 500a extends from the lower end portion of the front windshield 510 toward the front and downward direction.

[0052] Figure 7A : : The directional gain diagram in the horizontal plane when the front conductor 500a is provided at the front lower part of the front antenna 10A and when it is not provided. Figure 7A The relationship between the numbers marked on the periphery of the gain graph and the directions indicated by the numbers is the same as that in Figure 5A The relationship between the numbers marked on the periphery of the gain graph and the directions indicated by the numbers is the same. Figure 7A In the figure, the dotted line pattern indicates that Figure 6A As shown, the horizontal plane directivity gain when the front conductor 500a is provided at the front lower portion of the front antenna 10A. Figure 7A In the figure, the solid line pattern indicates that Figure 6B The figure shows the directivity gain in the horizontal plane when the front conductor 500 a is not provided at the front lower portion of the front antenna 10A.

[0053] Figure 7B The vertical plane directivity gain diagrams are shown in FIG. 1 and FIG. 2 when the front conductor 500a is provided at the front lower portion of the front antenna 10A and when the front conductor 500a is not provided. Figure 7B The relationship between the numbers marked on the periphery of the gain graph and the directions indicated by the numbers is the same as that in Figure 5B The relationship between the numbers marked on the periphery of the gain graph and the directions indicated by the numbers is the same. Figure 7B In the figure, the dotted line pattern indicates that Figure 6A As shown, the directivity gain in the vertical plane is obtained when the front conductor 500 a is provided at the front lower portion of the front antenna 10A. Figure 7B In the figure, the solid line pattern indicates that Figure 6B The figure shows the in-vertical-plane directivity gain when the front conductor 500 a is not provided in the front lower portion of the front antenna 10A.

[0054] like Figure 7A As shown in FIG, whether or not there is a leading conductor 500a, the directivity gain in the horizontal plane is almost the same. Figure 7BAs shown, the gain deviation (the difference between the maximum and minimum gain values) in the vertical plane directional gain within the forward 60° to 120° range of the front antenna 10A's radiation direction is significantly reduced with the front conductor 500a compared to the case without the front conductor 500a. In other words, even when the radiation direction of the radio waves from the front antenna 10A is nearly parallel to the rear surface of the windshield 510 at the lower front side of the front antenna 10A's radiation plane, the radio waves radiated from the front antenna 10A can propagate on the upper surface of the front conductor 500a, which is located forward of the windshield 510 (outward as viewed from the vehicle interior). Therefore, compared to the case without the front conductor 500a, the gain of the front antenna 10A in the left-right direction of the vehicle 50 can be maintained. The greater the half-value angle of the front antenna 10A, the better the gain maintained in the left-right direction of the vehicle 50.

[0055] use Figure 6A 、 Figure 6B 、 Figure 7A as well as Figure 7B The matters described for the front antenna 10A can also be similarly applied to the rear antenna 10B.

[0056] Next, the shapes of the hood 504 and the trunk lid 506 will be described.

[0057] According to the verification results of the inventors, the angles of the hood 504 and the trunk lid 506 relative to the X direction will affect the radiation characteristics of the front antenna 10A and the rear antenna 10B.

[0058] Figure 8 1 and 2 are diagrams showing model examples of different angles of the leading body 500 a relative to the horizontal direction. Figure 8 In the illustrated example, as indicated by the arrow near the leading conductor 500a, the front end of the leading conductor 500a is movable downward with the portion of the leading conductor 500a near the lower end of the front windshield 510 as the center.

[0059] Figure 9A : is the in-horizontal-plane directivity gain diagram at different angles of the leading conductor 500a relative to the horizontal direction. Figure 9B is the vertical plane directivity gain diagram of the front conductor 500a at different angles relative to the horizontal direction. Figure 9A The relationship between the numbers marked on the periphery of the gain graph and the directions indicated by the numbers is the same as that in Figure 5A The relationship between the numbers marked on the periphery of the gain graph and the directions indicated by the numbers is the same. Figure 9B The relationship between the numbers marked on the periphery of the gain graph and the directions indicated by the numbers is the same as that in Figure 5BThe relationship between the numbers marked on the periphery of the gain graph and the directions indicated by the numbers is the same.

[0060] Figure 9A as well as Figure 9B In, such as Figure 8 As shown, with respect to the state where the leading conductor 500a is tilted at 0° relative to the X direction, the front end of the leading conductor 500a is tilted downward by 30°, 60° or 90° with the portion near the lower end of the forward windshield 510 of the leading conductor 500a as the center. Figure 9A as well as Figure 9B In FIG. 5 , the inclination angle of the leading conductor 500 a with respect to the X direction is 0°, which means that the leading conductor 500 a is parallel to the X direction. Figure 9A as well as Figure 9B The solid line pattern, the dashed line pattern, the dotted line pattern, and the dashed line pattern represent gains when the inclination angles of the front conductor 500 a with respect to the X direction are 0°, 30°, 60°, and 90°, respectively.

[0061] like Figure 9A As shown, the directional gain in the horizontal plane (between 0° and 90°, and between 270° and less than 360°) is lowest when the front conductor 500a is tilted at 90° with respect to the X-direction, and gradually increases as the front conductor 500a approaches the X-direction. When the front conductor 500a is perpendicular to the X-direction, it can be said that the front conductor 500a contributes little to the radiation of radio waves from the front antenna 10A. However, as the front conductor 500a approaches the X-direction, the radio waves radiated from the front antenna 10A can propagate along the front conductor 500a, and the gain on the front side of the front antenna 10A can be improved. For example, when the front conductor 500a is tilted at -6° with respect to the X-direction (an angle close to downward relative to the X-direction), the radio waves propagate at an elevation angle of -6°, resulting in a higher gain in the depression direction relative to the horizontal plane. Therefore, when communicating with others via V2X communication using the front antenna 10A, the tilt angle of the front conductor 500a with respect to the X-direction is preferably set to, for example, between -30° and +30°. By setting the inclination angle of the front conductor 500 a with respect to the X direction within this range, the gain of the front antenna 10A can be improved.

[0062] like Figure 9B As shown, the fluctuation in the directional gain in the vertical plane within the elevation angle range on the front side of the front antenna 10A, that is, the fluctuation in the directional gain in the vertical plane within the range of 60° to 120°, is smaller when the front conductor 500a is tilted at 0° with respect to the X-direction than when the front conductor 500a is tilted at a greater angle than 0°. Therefore, when the front conductor 500a is positioned close to the X-direction, the front antenna 10A can stably radiate radio waves in the elevation angle range on the front side.

[0063] The shape of the leading conductor 500a is not particularly limited. For example, the leading conductor 500a may be a flat plate. Alternatively, a portion of the leading conductor 500a may be provided with a concave-convex shape or an R-shaped shape. For example, by providing a shape in which the leading conductor 500a tilts downward as it approaches the front end of the vehicle body 500, the propagation characteristics of radio waves directed downward from the horizontal plane can be improved, thereby increasing the directivity gain at the depression angle.

[0064] use Figure 8 、 Figure 9A as well as Figure 9B The matters described for the front antenna 10A can also be similarly applied to the rear antenna 10B.

[0065] Figure 10A This is a diagram showing a first example of the back conductor 500b according to the embodiment. Figure 10B This is a diagram showing a second example of the back conductor 500b according to the embodiment.

[0066] Figure 10A or Figure 10B The rear conductor 500b shown is a hatchback door or a structure similar to a hatchback door. For example, the hatchback door of a van is nearly vertical relative to the X direction. Figure 10A or Figure 10B As shown, a portion of the rear conductor 500b may extend substantially parallel to the X-direction from the lower end portion of the rear windshield 520. When a portion of the rear conductor 500b extends substantially parallel to the X-direction from the lower end portion of the rear windshield 520, the in-horizontal-plane directional gain of the rear antenna 10B can be improved compared to a case where the rear conductor 500b is simply perpendicular to the X-direction. Figure 10A In the illustrated example, the rear conductor 500 b includes a portion substantially parallel to the X direction and a portion extending from a front end of the portion substantially parallel to the X direction and substantially parallel to the Z direction. Figure 10B In the illustrated example, the rear conductor 500 b includes a portion substantially parallel to the X direction and a portion extending from a rear end of the portion substantially parallel to the X direction and substantially parallel to the Z direction.

[0067] The rear conductor 500b can be formed using a variety of methods. For example, a portion of the vehicle body 500 can be bent into an L-shape. Alternatively, a conductor roughly parallel to the Z direction can be pre-installed, and then a conductor roughly parallel to the X direction can be added later. Alternatively, a spoiler can be used. The rear conductor 500b can also be a single conductor. Alternatively, the rear conductor 500b can be integrated with the vehicle body 500. The rear conductor 500b can also be attached to the vehicle body 500 by being located on at least one of the outer side or inner side of the resin material.

[0068] use Figure 10Aas well as Figure 10B The matters described for the rear antenna 10B can also be similarly applied to the front antenna 10A.

[0069] Next, the influence of black ceramic 512 provided on front windshield 510 and the distance between black ceramic 512 and front antenna 10A will be described. The following description of the influence of black ceramic 512 provided on front windshield 510 and the distance between black ceramic 512 and front antenna 10A also applies to the influence of black ceramic provided on rear windshield 520 and the distance between black ceramic and rear antenna 10B.

[0070] Black ceramic is printed on the peripheral surfaces of vehicle windows such as the front windshield 510 and rear windshield 520. The black ceramic protects the adhesive used when assembling the front windshield 510 and rear windshield 520 to the vehicle body 500. Black ceramic typically contains aluminum oxide and titanium carbide added to the aluminum oxide, and may contain other substances as needed. Aluminum oxide has a low dissipation factor. On the other hand, titanium carbide is conductive. Therefore, a portion of the electromagnetic waves that penetrate the black ceramic flows as current through the titanium carbide, potentially converting it into heat. This phenomenon is similar to the performance of dielectric loss-type radio wave absorbers and can hinder radio wave penetration. Therefore, when antennas such as the front antenna 10A and the rear antenna 10B are placed at the ends of vehicle windows such as the front windshield 510 and rear windshield 520, it is preferable to place the antennas at a predetermined distance from the black ceramic. Specifically, the front overlapping portion 510a and the black ceramic are preferably offset from each other. Similarly, the rear overlapping portion 520a and the black ceramic are preferably offset from each other.

[0071] Figure 11 This is a diagram showing the arrangement of the black ceramic 512 of the front windshield 510 and the front antenna 10A as viewed from the left of the vehicle 50 . Figure 11 In FIG. 1 , the front antenna 10A is shown as a substantially rectangular parallelepiped antenna case that houses an antenna element.

[0072] Figure 11 In the example shown, black ceramic 512 is provided on the rear surface of the lower end of windshield 510. Light hardly penetrates black ceramic 512. Therefore, the portion of the lower end of windshield 510 where black ceramic 512 is provided does not function as a light-transmitting element. Therefore, the lower end of the portion of windshield 510 that functions as a light-transmitting element serves as the upper end of black ceramic 512.

[0073] Figure 11In the example shown, the front overlap portion 510a and the black ceramic 512 are offset from each other. The distance L from the upper end of the black ceramic 512 to the lower surface of the front antenna 10A is, for example, 20 mm. As long as the black ceramic 512 does not interfere with the radio waves radiated from the rear antenna 10B, Figure 11 The distance L shown can be freely set. If black ceramic 512 is present in the radio wave radiation direction of front antenna 10A, the gain of front antenna 10A may be reduced. Therefore, front antenna 10A is arranged at a predetermined distance from black ceramic 512 in the Z direction.

[0074] Similar to the front antenna 10A, the rear antenna 10B can be positioned at a predetermined distance from the black ceramic provided at the lower end of the rear windshield 520. The distance from the top of the black ceramic provided at the lower end of the rear windshield 520 to the lower surface of the rear antenna 10B housing is, for example, 5 mm. This distance can be freely set as long as the black ceramic 512 does not interfere with the radio waves radiated from the rear antenna 10B.

[0075] Figure 12 This is a diagram showing the front antenna 10A, the front windshield 510 , and the black ceramic 512 as viewed from the front of the vehicle 50 . Figure 12 In FIG, the front antenna 10A is shown as a substantially rectangular parallelepiped antenna case that houses an antenna element.

[0076] When viewed from the front, the black ceramic 512 defines a recess 512a. When viewed from the front, the recess 512a at least partially surrounds the front overlapping portion 510a. Specifically, when viewed from the front, the recess 512a at least partially surrounds the lower end of the front antenna 10A. Thus, the recess 512a prevents overlap of the front antenna 10A and the black ceramic 512 in the X direction. Therefore, compared to a case where the recess 512a is not provided, the degree of freedom in the mounting position of the front antenna 10A can be increased. Thus, compared to a case where the recess 512a is not provided, the front antenna 10A can be positioned closer to the lower end of the front windshield 510 when viewed from the front, thereby improving the gain of the front antenna 10A.

[0077] use Figure 12 The matters described with respect to the front antenna 10A, the front windshield 510, and the black ceramic 512 also apply to the rear antenna 10B, the rear windshield 520, and the black ceramic provided on the rear windshield 520. In other words, the black ceramic provided on the rear windshield 520 may also be provided with a recessed portion corresponding to the recessed portion 512a of the black ceramic 512 provided on the front windshield 510.

[0078] Next, the angle of the front windshield 510 with respect to the X direction, the angle of the rear windshield 520 with respect to the X direction, the distance between the front antenna 10A and the front windshield 510 , and the distance between the rear antenna 10B and the rear windshield 520 are described.

[0079] The angle of the front windshield 510 relative to the X direction contributes to at least one of the penetration and scattering of the radio waves irradiated from the front antenna 10A. In particular, if the angle of the rear surface of the front overlapping portion 510a relative to the X direction is set to be greater than 10° and less than 40°, the reflection of radio waves based on the front windshield 510 can be minimized. The same applies to the angle of the rear windshield 520 relative to the X direction. In the first embodiment, the angle of the front windshield 510 relative to the X direction is approximately 31°. In the first embodiment, the angle of the rear windshield 520 relative to the X direction is approximately 23.5°. However, in order to obtain the desired antenna gain within an arbitrary range of elevation and azimuth angles, the angles of the front windshield 510 and the rear windshield 520 relative to the X direction can be freely set.

[0080] The distance between the front antenna 10A and the front windshield 510 also contributes to the radiation of radio waves from the front antenna 10A. Therefore, the front antenna 10A and the front windshield 510 are preferably arranged with a predetermined distance therebetween. The same applies to the rear antenna 10B and the rear windshield 520.

[0081] Figure 13 This is a diagram showing the arrangement of the front antenna 10A and the front windshield 510 as viewed from the left side of the vehicle 50 . Figure 13 In FIG, the front antenna 10A is shown as a substantially rectangular parallelepiped antenna case that houses an antenna element.

[0082] like Figure 13 As shown, in the first embodiment, the X-direction gap Gx between the front surface of the front antenna 10A and the portion of the rear surface of the front windshield 510 closest to the front surface of the front antenna 10A in the X direction is 20 mm, and the Z-direction gap Gz between the top surface of the front antenna 10A and the portion of the rear surface of the front windshield 510 closest to the top surface of the front antenna 10A in the Z direction is 11.8 mm. In the first embodiment, the X-direction gap between the rear surface of the rear antenna 10B and the portion of the front surface of the rear windshield 520 closest to the rear surface of the rear antenna 10B in the X direction is 20 mm, and the Z-direction gap between the top surface of the rear antenna 10B and the portion of the front surface of the rear windshield 520 closest to the top surface of the rear antenna 10B in the Z direction is 8.5 mm.

[0083] The radiation characteristics, impedance, and other characteristics of the front antenna 10A may sometimes change depending on the proximity of the front antenna 10A and the front windshield 510. Figure 13 The interval Gx shown is preferably 1 / 4 times or more of the wavelength of the operating frequency of the front antenna 10A. On the other hand, if the front antenna 10A and the front windshield 510 are separated from each other, the radio waves radiated from the front antenna 10A may be reflected by the front windshield 510. Therefore, Figure 13 The interval Gx shown is preferably equal to or smaller than, for example, 1 / 2 times the wavelength of the operating frequency of the front antenna 10A. Figure 13 The distance Gz shown is preferably equal to or greater than, for example, 1 / 10 times the wavelength of the operating frequency of the front antenna 10A. The same applies to the distance between the rear antenna 10B and the rear windshield 520.

[0084] The distance between the front antenna 10A and the front windshield 510 and the distance between the rear antenna 10B and the rear windshield 520 are not limited to the above examples, and these distances can be freely set so as to obtain desired antenna gains in any elevation and azimuth angle ranges.

[0085] Next, modifications of the radio wave penetrating body will be described.

[0086] Antennas such as the front antenna 10A and the rear antenna 10B can overlap with a radio wave penetrating body that is different from the vehicle glass such as the front windshield 510 and the rear windshield 520. Examples of radio wave penetrating bodies include resin bodies such as resin panels, resin covers, and resin parts. The resin body has radio wave permeability. The resin body may also have light permeability, or it may not have light permeability. The resin body is, for example, arranged inside the vehicle interior. The resin body is provided for purposes such as fixing the antenna or its peripheral parts, improving the aesthetics and design, and improving dustproofing, waterproofing, or durability.

[0087] In one example, a resin body such as a resin panel may be present on the radiation direction side of the antenna. In this example, for example, the resin body may be disposed between the antenna and the vehicle window.

[0088] In other examples, a resin body such as a resin cover may cover at least a portion of the antenna. In this other example, for example, the resin body may cover the antenna while the side of the resin body on which the vehicle glass is located relative to the antenna is open. In the case where the resin body covers the antenna while the side of the resin body on which the vehicle glass is located relative to the antenna is open, the antenna may be arranged in a space surrounded by the resin body and the vehicle glass. Alternatively, in this other example, the resin body may include the side on which the vehicle glass is located relative to the antenna and cover the antenna. In the case where the resin body includes the side on which the vehicle glass is located relative to the antenna and covers the antenna, the antenna may be arranged in a space surrounded by the resin body.

[0089] In another example, a resin body such as a resin component may be provided as a bracket for fixing the antenna to the vehicle.

[0090] The following describes an example in which the resin body tilts upward diagonally relative to the front-to-back direction as it moves from the front to the back. The antenna radiates radio waves from the back toward the resin body. Hereinafter, the portion of the resin body that overlaps with the image of the antenna projected in the front-to-back direction is referred to as the overlapping portion of the resin body. Similar to the front overlapping portion 510a of the embodiment, the overlapping portion of the resin body is located at a position offset toward the lower end of the resin body relative to the center portion between the upper and lower ends of the resin body. Thus, similar to the embodiment, compared to the case where the overlapping portion of the resin body is located at the center of the resin body and the case where the overlapping portion of the resin body is located at a position offset toward the upper end of the resin body relative to the center portion of the resin body, the scattering of radio waves radiated from the antenna on the resin body can be suppressed, thereby improving the directional gain. Similar to the embodiment, a conductor such as a sheet metal can be provided at the front lower portion of the antenna. Similar to the embodiment, the conductor is distributed forward relative to the lower end of the resin body. Similar to the embodiment, the provision of a conductor can improve the directional gain compared to the case where no conductor is provided.

[0091] As mentioned above, although embodiment and modification of this invention were demonstrated referring drawings, these are examples of this invention, and various structures other than what was described above can also be adopted.

[0092] According to this specification, an antenna device and a method for mounting an antenna device according to the following aspects are provided. (Method 1) In method 1, the antenna device has an antenna that radiates radio waves toward a radio wave penetrating body from the other side in a prescribed direction, the radio wave penetrating body has two end portions located on opposite sides of each other, and is inclined at a prescribed angle relative to the prescribed direction between the two end portions as it moves from one side in the prescribed direction toward the other side. The portion of the radio wave penetrating body that overlaps with the image projected by the antenna in the prescribed direction is located at a position offset toward the side where the end portion of one of the two end portions of the radio wave penetrating body is located, relative to the central portion between the two end portions of the radio wave penetrating body.

[0093] The "predetermined direction" corresponds to the "X direction" in the above-mentioned embodiment and its variations. The "radio wave penetrating body" corresponds to the "front windshield" and "rear windshield" in the above-mentioned embodiment and its variations. The "antenna" corresponds to the "front antenna" and "rear antenna" in the above-mentioned embodiment and its variations.

[0094] According to the above embodiment, the scattering of radio waves radiated from the antenna on the radio wave penetrating body can be suppressed compared to a case where the portion of the radio wave penetrating body that overlaps with the image of the antenna is located in the center of the radio wave penetrating body, or is located at a position offset from the center of the radio wave penetrating body toward the other end portion of the radio wave penetrating body. Thus, compared to a case where the portion of the radio wave penetrating body that overlaps with the image of the antenna is located in the center of the radio wave penetrating body, or is located at a position offset from the center of the radio wave penetrating body toward the other end portion of the radio wave penetrating body, directivity can be ensured over a wide range using a small number of antennas.

[0095] (Method 2) In aspect 2, the plurality of antennas are located on opposite sides to each other in the predetermined direction.

[0096] According to the above aspect, compared with the case of using a single antenna, directivity can be ensured over a wider range.

[0097] (Method 3) In aspect 3, the antenna is positioned with a conductor disposed on the one side relative to the end portion on the one side of the radio wave penetrating body.

[0098] According to the above aspect, the radio waves radiated from the antenna can propagate on the conductor, thereby ensuring the gain of the antenna compared to a case where no conductor is provided.

[0099] (Method 4) In aspect 4, the antenna is positioned in a state where the portion of the radio wave penetrating body that overlaps with the image of the antenna and the black ceramic provided on the radio wave penetrating body are offset from each other.

[0100] According to the above embodiment, compared to a case where the portion of the radio wave penetrating body that overlaps with the antenna image and the black ceramic overlaps, it is possible to suppress the penetration of radio waves radiated from the antenna by being blocked by the black ceramic. Thus, compared to a case where the portion of the radio wave penetrating body that overlaps with the antenna image and the black ceramic overlaps, it is possible to increase the gain of the antenna.

[0101] (Method 5) In aspect 5, the black ceramic defines a recessed portion that at least partially surrounds the portion of the radio wave penetrating body that overlaps with the image of the antenna.

[0102] According to the above aspect, the recessed portion can prevent the antenna and the black ceramic from overlapping in a predetermined direction, thereby increasing the degree of freedom of the antenna mounting position compared to a case where no recessed portion is provided.

[0103] (Method 6) In mode 6, the antenna and the portion of the radio wave penetrating body overlapping with the image of the antenna are arranged in the predetermined direction at an interval of not less than 1 / 4 times and not more than 1 / 2 times the wavelength of the operating frequency of the antenna.

[0104] According to the above embodiment, compared to a case where the spacing in a predetermined direction between the antenna and the portion of the radio wave penetrating object where the image of the antenna overlaps is less than 1 / 4 times the wavelength of the antenna's operating frequency, changes in the antenna's characteristics can be suppressed. According to the above embodiment, compared to a case where the spacing in a predetermined direction between the antenna and the portion of the radio wave penetrating object where the image of the antenna overlaps is greater than 1 / 2 times the wavelength of the antenna's operating frequency, reflection of radio waves radiated from the antenna on the radio wave penetrating object can be suppressed.

[0105] (Method 7) In mode 7, the radio wave penetrating body is a light penetrating body.

[0106] According to the above aspect, in a state where the antennas are arranged on the light-transmitting body, directivity can be ensured over a wide range by a small number of antennas.

[0107] (Method 8) In method 8, the antenna is a V2X antenna.

[0108] According to the above method, directivity can be ensured over a wide range using a small number of V2X antennas.

[0109] (Method 9) In method 9, in a method for mounting an antenna device, an antenna that radiates radio waves from the other side in a prescribed direction toward a radio wave penetrating body is positioned, the radio wave penetrating body having two end portions located on opposite sides of each other, and being inclined at a prescribed angle relative to the prescribed direction between the two end portions as it moves from one side in the prescribed direction toward the other side, so that a portion of the radio wave penetrating body that overlaps with an image projected by the antenna in the prescribed direction is located at a position offset toward a side where an end portion on one side of the two end portions of the radio wave penetrating body is located, relative to a central portion between the two end portions of the radio wave penetrating body.

[0110] According to the above aspect, similar to aspect 1, directivity can be ensured over a wide range using a small number of antennas.

[0111] (Method 10) In aspect 10, the plurality of antennas are located on opposite sides to each other in the predetermined direction.

[0112] According to the above aspect, compared with the case of using a single antenna, directivity can be ensured over a wider range.

[0113] (Method 11) In aspect 11, the antenna is positioned with a conductor disposed on the one side relative to the end portion on the one side of the radio wave penetrating body.

[0114] According to the above aspect, similarly to aspect 3, the gain of the antenna can be ensured compared to the case where no conductor is provided.

[0115] (Method 12) In aspect 12, the antenna is positioned so that the portion of the radio wave penetrating body that overlaps with the image of the antenna and the black ceramic provided on the radio wave penetrating body are offset from each other.

[0116] According to the above aspect, similarly to aspect 4, the gain of the antenna can be improved compared to the case where the portion of the radio wave penetrating body that overlaps with the image of the antenna overlaps with the black ceramic.

[0117] (Method 13) In aspect 13, the black ceramic defines a recessed portion that at least partially surrounds the portion of the radio wave penetrating body that overlaps with the image of the antenna.

[0118] According to the above aspect, similarly to aspect 5, the degree of freedom of the mounting position of the antenna can be increased compared to a case where no recess is provided.

[0119] (Method 14) In aspect 14, the antenna and the portion of the radio wave penetrating body overlapping with the image of the antenna are arranged in the predetermined direction at an interval of not less than 1 / 4 times and not more than 1 / 2 times the wavelength of the operating frequency of the antenna.

[0120] According to the above aspect, similarly to aspect 6, it is possible to suppress changes in antenna characteristics and reflection of radio waves radiated from the antenna on a radio wave penetrating body.

[0121] (Method 15) In mode 15, the radio wave penetrating body is a light penetrating body.

[0122] According to the above aspect, in a state where the antennas are arranged on the light-transmitting body, directivity can be ensured over a wide range by a small number of antennas.

[0123] (Method 16) In method 16, the antenna is a V2X antenna.

[0124] According to the above method, directivity can be ensured over a wide range using a small number of V2X antennas.

[0125] This application claims priority based on U.S. Provisional Patent Application No. 63 / 453,773 filed on March 22, 2023, and incorporates all of its disclosures herein. Description of Reference Signs

[0126] 1. 1K antenna assembly, 10A front antenna, 10B rear antenna, 50 vehicle, 110A front antenna housing, 120A front cable, 500 vehicle body, 500a front conductor, 500b rear conductor, 502 roof, 504 hood, 506 trunk lid, 510 front windshield, 510a and 510aK front overlapping portion, 512 black ceramic, 512a recess, 520 rear windshield, 520a and 520aK rear overlapping portion.

Claims

1. An antenna device, wherein: An antenna radiates radio waves from the other side of a predetermined direction toward a radio wave penetrating body, wherein the radio wave penetrating body has two end portions located on opposite sides of each other, and is inclined at a predetermined angle relative to the predetermined direction between the two end portions as it moves from one side in the predetermined direction toward the other side. The portion of the radio wave penetrating body that overlaps with the image projected by the antenna in the prescribed direction is located at a position offset toward the side where the end portion of one of the two end portions of the radio wave penetrating body is located, relative to the central portion between the two end portions of the radio wave penetrating body.

2. The antenna device according to claim 1, wherein The plurality of antennas are located on opposite sides to each other in the predetermined direction.

3. The antenna device according to claim 1 or 2, wherein: The antenna is positioned with respect to the end portion on the one side of the radio wave penetrating body in a state where a conductor is arranged on the one side.

4. The antenna device according to claim 1 or 2, wherein: The antenna is positioned in a state where the portion of the radio wave penetrating body that overlaps with the image of the antenna and the black ceramic provided on the radio wave penetrating body are offset from each other.

5. The antenna device according to claim 4, wherein: The black ceramic defines a recessed portion that at least partially surrounds the portion of the radio wave penetrating body that overlaps with the image of the antenna.

6. The antenna device according to claim 1 or 2, wherein: The antenna and the portion of the radio wave penetrating body overlapping with the image of the antenna are arranged in the predetermined direction at an interval of not less than 1 / 4 times and not more than 1 / 2 times the wavelength of the operating frequency of the antenna.

7. The antenna device according to claim 1 or 2, wherein: The radio wave penetrating body is a light penetrating body.

8. The antenna device according to claim 1 or 2, wherein: The antenna is a V2X antenna.

9. A method for mounting an antenna device, wherein: An antenna that radiates radio waves from the other side in a predetermined direction toward a radio wave penetrating body is positioned, wherein the radio wave penetrating body has two end portions located on opposite sides of each other and is inclined at a predetermined angle relative to the predetermined direction between the two end portions as it moves from one side in the predetermined direction toward the other side. The portion of the radio wave penetrating body that overlaps with the image projected by the antenna in the prescribed direction is located at a position offset toward the side where the end portion of one of the two end portions of the radio wave penetrating body is located, relative to the central portion between the two end portions of the radio wave penetrating body.

10. The method for mounting an antenna device according to claim 9, wherein: The plurality of antennas are positioned on opposite sides to each other in the predetermined direction.

11. The method for mounting an antenna device according to claim 9 or 10, wherein: The antenna is positioned with respect to the end portion on the one side of the radio wave penetrating body in a state where a conductor is arranged on the one side.

12. The method for mounting an antenna device according to claim 9 or 10, wherein: The antenna is positioned so that the portion of the radio wave penetrating body that overlaps with the image of the antenna and the black ceramic provided on the radio wave penetrating body are offset from each other.

13. The method for mounting an antenna device according to claim 12, wherein: The black ceramic defines a recessed portion that at least partially surrounds the portion of the radio wave penetrating body that overlaps with the image of the antenna.

14. The method for mounting an antenna device according to claim 9 or 10, wherein: The antenna and the portion of the radio wave penetrating body overlapping with the image of the antenna are arranged in the predetermined direction at an interval of not less than 1 / 4 times and not more than 1 / 2 times the wavelength of the operating frequency of the antenna.

15. The method for mounting an antenna device according to claim 9 or 10, wherein: The radio wave penetrating body is a light penetrating body.

16. The method for mounting an antenna device according to claim 9 or 10, wherein: The antenna is a V2X antenna.

Images