Vehicle antenna device and vehicle

Abstract

Provided are a vehicle antenna device and a vehicle, the vehicle antenna device having a good average gain of horizontally polarized waves and vertically polarized waves arriving at a housing of a vehicle from a horizontal direction, and having a good appearance without protruding to the outside of the roof of the vehicle.　This vehicle antenna device is attached to a vehicle body and has a first opening provided in a first metal member of a roof part of the vehicle body and a second opening provided in a second metal member of a side part of the vehicle body and adjacent to the first opening. The vehicle antenna device includes a dielectric substrate provided in the first opening, and an antenna element for a monopole antenna formed on a vehicle interior-side main surface of the dielectric substrate, the antenna element being provided with a first radiation element extending parallel to the inner edge of the first opening. When the wavelength in free space of a radio wave transmitted or received by the antenna element is denoted by λ, the length in a lateral direction of the second opening is 0.05-0.25 λ when the second opening is viewed from the front.

Description

Vehicle antenna device and vehicle

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

[0002] Known examples of antenna devices mounted on vehicles include shark fin antennas, which house various antenna elements in a protruding cover on the vehicle roof. Some vehicle models have an opening in the roof, with roof glass placed in the opening. When the roof glass is placed in the opening, a through-hole is formed in the roof glass, and power lines, signal lines, and the like for the shark fin antenna are connected to a power source or signal source inside the vehicle through the through-hole. The antenna device is mounted on the roof glass using a fastener provided in the through-hole. The fastener is fixed to a seat inside the vehicle interior by screwing it in via elastic layers (sealing members) provided on the exterior and interior surfaces of the roof glass and inside the through-hole (see, for example, Patent Document 1).

[0003] Special Publication No. 2010-510954

[0004] Conventional antenna devices receive radio waves arriving from the horizontal direction, so the antenna is placed on the window glass installed in the opening on the side of the vehicle to avoid being blocked by the vehicle housing. Similarly, antennas installed on the vehicle roof also receive radio waves arriving from the horizontal direction, so they are installed in a way that protrudes outside the vehicle roof, like a pole antenna or shark fin antenna, to avoid being blocked by the vehicle housing. Antennas that protrude outside the vehicle roof look unattractive and can detract from the overall design of the vehicle.

[0005] Therefore, the object is to provide a vehicle antenna device and a vehicle that has a good average gain of horizontally polarized waves and vertically polarized waves arriving from the horizontal direction relative to the vehicle housing, does not protrude outside the vehicle roof, and has a good appearance.

[0006] A vehicle antenna device according to an embodiment of the present disclosure is a vehicle antenna device that is attached to a vehicle body and has a first opening provided in a first metal member on a roof portion of the vehicle body and a second opening provided in a second metal member on a side of the vehicle body and adjacent to the first opening, and includes a dielectric substrate provided in the first opening, and an antenna element for a monopole antenna formed on a main surface of the dielectric substrate facing the interior of the vehicle, the antenna element having a first radiating element extending parallel to the inner edge of the first opening, wherein, when the wavelength in free space of the radio waves transmitted or received by the antenna element is λ, the lateral length of the second opening, when viewed from the front, is 0.05λ or more and 0.25λ or less.

[0007] To provide a vehicle antenna device and a vehicle having a good appearance, which has a good average gain of horizontally polarized waves and vertically polarized waves arriving from the horizontal direction relative to a vehicle housing and does not protrude outside the roof of the vehicle.

[0008] 1 is a diagram showing an example of the configuration of a vehicle 1 equipped with a vehicle antenna device 100 according to an embodiment. FIG. 1 is a diagram showing an example of the configuration of the vehicle antenna device 100. FIG. 2 is a diagram showing an example of a simulation model of the vehicle 1 including the vehicle antenna device 100 according to the embodiment. FIG. 3 is a diagram showing an example of a simulation model of a comparative vehicle antenna device 50. FIG. 4 is a diagram showing an example of a simulation result of the frequency characteristics of the gain of an antenna element 120. FIG. 5 shows the electric field distribution of radio waves radiated from the antenna element 120 of the comparative simulation model. FIG. 6 shows the electric field distribution of radio waves radiated from the antenna element 120 of the simulation model according to the embodiment. FIG. 7 is a diagram explaining an example of the definition of the width and height of an opening of a vehicle body 10. FIG. 8 is a diagram showing an example of a simulation result of the average gain of the antenna element 120 relative to the distance D. FIG. 9 is a diagram showing an example of a simulation result of the average gain of the antenna element 120 relative to the width Ws of the opening 12. FIG. 10 is a diagram showing an example of a simulation result of the average gain of the antenna element 120 relative to the height Hs of the opening 12. FIG. 11 is a diagram showing an example of a simulation result of the average gain of the antenna element 120 relative to the width Wr of the opening 13R for the rear window. FIG. 12 is a diagram showing an example of a simulation result of the average gain of the antenna element 120 relative to the width Wf of the opening 13F for the windshield. FIG. 1 is a diagram showing an example of a simulation result of the average gain of the antenna element 120 relative to the width Wf of the windshield opening 13F and the width Wr of the rear window opening 13R. FIG. 2 is a diagram showing an example of a simulation result of the average gain of the antenna element 120 relative to the width Wf of the windshield opening 13F and the width Wr of the rear window opening 13R. FIG. 3 is a diagram showing an example of a simulation result of the average gain of the antenna element 120 relative to the vehicle width. FIG. 4 is a characteristic diagram showing an example of the dimensions of the opening required for the average gain of the antenna element 120 to be −7 dB or more. FIG. 5 is a diagram explaining an example of a variation of the antenna element 120. FIG. 6 is a diagram explaining an example of a variation of the antenna element 120. FIG. 7 is a diagram explaining an example of a variation of the antenna element 120.

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

[0010] In the following description, the XYZ coordinate system is defined. The direction parallel to the X axis (X direction), the direction parallel to the Y axis (Y direction), and the direction parallel to the Z axis (Z direction) are perpendicular to each other. For ease of explanation, the -Z direction may be referred to as the lower side or bottom, and the +Z direction may be referred to as the upper side or top, but this does not indicate a universal vertical relationship. Planar view refers to a view from the XY plane. In the following description, the length, width, thickness, etc. of each part may be exaggerated to make the configuration easier to understand. Terms such as parallel, right angle, orthogonal, horizontal, vertical, and top and bottom may be misaligned to the extent that they do not impair the effects of the embodiments.

[0011] Examples of the vehicle antenna device in this embodiment include roof glass attached to the ceiling of the vehicle, a windshield (front glass) attached to the front of the vehicle, fixed side glass (including front bench glass and rear quarter glass) attached to the side of the vehicle, and rear glass attached to the rear of the vehicle. The vehicle antenna device is not limited to these examples. Below, as an example, a form in which the vehicle antenna device is used as roof glass will be described.

[0012] The vehicle may be, for example, an automobile such as an electric vehicle (EV), a plug-in hybrid electric vehicle (PHEV), a hybrid vehicle (HV), a gasoline-powered vehicle, or a diesel-powered vehicle. The vehicle may also be a train or steam locomotive. A vehicle is an example of a moving body that transports passengers.

[0013] In the following description, the term "outside the cabin" refers to the outside of the vehicle (outside the cabin), and the term "inside the cabin" refers to the inside of the vehicle (inside the cabin). In the following description, the terms "left" and "right" refer to the left and right directions in the direction of travel of the vehicle.

[0014] FIG. 1 is a diagram showing an example of the configuration of a vehicle 1 to which a vehicle antenna device 100 according to an embodiment is attached.

[0015] The vehicle 1 includes a vehicle body 10 and a vehicle antenna device 100. The vehicle 1 is, for example, an electric vehicle (EV), a plug-in hybrid electric vehicle (PHEV), a hybrid vehicle (HV), a gasoline vehicle, a diesel vehicle, or other automobile. The vehicle may also be a train or steam locomotive.

[0016] <Vehicle body 10> The vehicle body 10 has an opening 11 provided in the roof (roof portion), openings 12 provided on the left and right sides, an opening 13F for a windshield (front window), and an opening 13R for a rear window. The opening 11 is an example of a first opening, and the opening 12 is an example of a second opening.

[0017] The vehicle body 10 is made of steel, for example, but may also be made of aluminum or other metals. The vehicle body 10 may also be made of a material other than metal, as long as the roof panel on the surface of the roof where the opening 11 is provided, or the structure inside the roof that surrounds the opening 11, is made of metal. The vehicle body 10 may also be made of metal, as long as the door panel, door sash, belt line, A-pillar, B-pillar, C-pillar, or portion of the roof located at the top of the side window that surrounds the opening 12 when the door is closed, is made of metal. In the case of a vehicle body without door sashes, the opening 12 is defined by the portion surrounded by the top of the door, the A-pillar, the B-pillar, or the C-pillar, and the portion of the roof located at the top of the side window when the door is closed.

[0018] The metal structure surrounding the opening 11 is an example of a first metal member. The metal member surrounding the opening 12 when the door is closed is an example of a second metal member.

[0019] <Opening 11> The opening 11 is, for example, an opening for a roof glass, but is not limited to the roof glass and may be an opening for providing a dielectric outer panel or the like provided on the roof of the vehicle body 10. The opening 11 is a window frame provided on the roof of the vehicle body 10 and is provided with a flange.

[0020] The roof glass, the dielectric outer panel, etc. may be movable relative to the opening 11 for opening and closing, or may be fixedly attached to the opening 11. If the roof glass, the outer panel, etc. are movable relative to the opening 11 for opening and closing, they may be configured to be freely opened and closed relative to the opening 11 by a drive mechanism such as a motor or regulator provided on the vehicle body 10. Here, as an example, a configuration will be described in which the vehicle antenna device 100 is roof glass that is fixedly attached to the opening 11.

[0021] <Openings 12> The openings 12 are, for example, openings for side windows on the left and right sides. In the vehicle 1 shown in Fig. 1, for example, there are three openings 12 on each side. The three openings 12 on the left side of the vehicle 1 shown in Fig. 1 are provided for a left front side window, a left rear side window, and a left rear quarter window. The same applies to the right side of the vehicle 1.

[0022] The opening 12 is not limited to the front side window, the left rear side window, and the left rear quarter window, but may also be an opening provided with a front quarter window, a dielectric outer panel, or the like provided on the left or right side of the vehicle body 10. The opening 12 is a window frame provided on the left or right side of the vehicle body 10. These side windows, dielectric outer panels, etc. may be movable relative to the opening 12, or may be fixedly attached to the opening 12.

[0023] <Configuration of Vehicle Antenna Device 100> Fig. 2 is a diagram showing an example of the configuration of the vehicle antenna device 100. Fig. 2 shows a flange 11A provided at the opening 11 of the vehicle body 10. The vehicle antenna device 100 includes a laminated glass 110 and an antenna element 120. The laminated glass 110 is an example of a dielectric substrate. The vehicle antenna device 100 may be configured to include a single-layer glass instead of the laminated glass 110, but here, as an example, a configuration including the laminated glass 110 will be described.

[0024] In FIG. 2 , the XYZ coordinate system is defined and explained. The direction parallel to the X axis (X direction), the direction parallel to the Y axis (Y direction), and the direction parallel to the Z axis (Z direction) are perpendicular to one another. The +Z direction side is the exterior side of the vehicle body 10. The Z axis extends in the normal direction of the laminated glass 110. In the following, a planar view refers to viewing an object in the XY plane in the extension direction of the Z axis. As an example, the +X direction is the forward direction of the vehicle 1, and the +Y direction is the leftward direction of the vehicle 1.

[0025] <Laminated Glass 110> The laminated glass 110 has glass plates 111 and 112, an intermediate film 113, a ceramic layer 114, and a Low-E (Low Emissivity) film 115. The glass plate 111 is an example of a first glass plate, and the glass plate 112 is an example of a second glass plate. The ceramic layer 114 is an example of a shielding layer. The Low-E film 115 is an example of a conductive film. The laminated glass 110 is fixed to the flange 11A with an adhesive 20.

[0026] The laminated glass 110 is formed by bonding a glass plate 111 provided on the exterior side of the vehicle body 10 and having a ceramic layer 114 and a Low-E film 115 formed thereon to a glass plate 112 provided on the interior side of the vehicle body 10 via an intermediate film 113 disposed between the glass plates 111 and 112.

[0027] <Glass Plates 111 and 112> The glass plates 111 and 112 are transparent, flat glass plates. The glass plate 111 has an outdoor-side main surface 111A and an indoor-side main surface 111B. The main surface 111A is an example of a first main surface, and the indoor-side main surface 111B is an example of a second main surface. The glass plate 112 has an outdoor-side main surface 112A and an indoor-side main surface 112B. The main surface 112A is an example of a third main surface, and the indoor-side main surface 112B is an example of a fourth main surface. The main surfaces 111B and 112B are examples of indoor-side main surfaces.

[0028] The glass plates 111 and 112 may be inorganic glass or organic glass. Examples of inorganic glass that can be used include, without particular limitation, soda-lime glass, aluminosilicate glass, borosilicate glass, alkali-free glass, and quartz glass. Among these, soda-lime glass is particularly preferred from the viewpoints of manufacturing cost and formability. The forming method of the glass plates 111 and 112 is not particularly limited. For example, in the case of inorganic glass, glass plates formed by a float method or the like are preferred.

[0029] When the glass plates 111 and 112 are inorganic glass, they may be either untempered glass or tempered glass. Untempered glass is produced by forming molten glass into a plate shape and slowly cooling it. Tempered glass is produced by forming a compressive stress layer on the surface of untempered glass, and may be either air-cooled tempered glass or chemically tempered glass.

[0030] When the tempered glass is physically tempered glass (e.g., air-cooled tempered glass), the glass surface may be tempered by a process other than slow cooling, such as rapidly cooling a uniformly heated glass sheet from a temperature near its softening point during bending, thereby generating a compressive stress layer on the glass surface due to the temperature difference between the glass surface and the interior of the glass. When the tempered glass is chemically tempered glass, the glass surface may be tempered by generating compressive stress on the glass surface using an ion exchange method or the like after bending. Furthermore, glass that absorbs ultraviolet or infrared light may be used as the glass sheets 111 and 112. The glass sheets 111 and 112 are preferably transparent, but may also be colored to the extent that transparency is not impaired. Furthermore, the glass sheets 111 and 112 do not have to be transparent.

[0031] The laminated glass 110 may have a curved shape such that the exterior side is convex when attached to the vehicle body 10. The laminated glass 110 may have a single-curve shape bent in only one direction, or may have a complex-curve shape bent in two directions (for example, the vertical direction when the laminated glass 110 is attached to the vehicle body 10 and the horizontal direction perpendicular to the vertical direction). Gravity forming, press forming, roller forming, or the like is used to bend the laminated glass 110. When the laminated glass 110 is bent to a predetermined curvature, the radius of curvature of the laminated glass 110 may be 1,000 mm or more and 100,000 mm or less.

[0032] Furthermore, when the laminated glass 110 is attached to the vehicle body 10, the thickness of the glass plate 111 located on the exterior side and the thickness of the glass plate 112 located on the interior side may be the same or different. The thickness of the glass plate 111 is preferably 1.0 mm or more and 3.0 mm or less. A thickness of 1.0 mm or more of the glass plate 111 provides sufficient strength, such as resistance to stone chips, while a thickness of 3.0 mm or less prevents the laminated glass 110 from becoming too heavy, which is preferable in terms of vehicle fuel economy. The thickness of the glass plate 112 is preferably 0.3 mm or more and 2.3 mm or less. A thickness of 0.3 mm or more of the glass plate 112 provides good handling, while a thickness of 2.3 mm or less prevents the laminated glass 110 from becoming too heavy. It is preferable that the thicknesses of the glass plates 111 and 112 are each 1.8 mm or less, since this allows the laminated glass 110 to achieve both lightweight and sound insulation. The total thickness of the laminated glass 110 is preferably 2.5 mm or more and 7 mm or less. When the thickness of the glass plate 112 is 1.0 mm or less, the glass plate 112 may be chemically strengthened glass. When the glass plate 112 is chemically strengthened glass, it is preferable that the compressive stress value of the glass surface is 300 MPa or more and the depth of the compressive stress layer is 2 μm or more.

[0033] When the glass plates 111 and 112 are made of organic glass, examples of the material for the organic glass include transparent resins such as polycarbonate and acrylic resins (for example, polymethyl methacrylate).

[0034] When single-layer glass is used instead of the laminated glass 110, the single-layer glass is preferably tempered glass, for example. Physically tempered glass (e.g., air-cooled tempered glass) can be used as the tempered glass. In the case of single-layer glass, the thickness of the glass plate is preferably 2.0 mm or more and 5.0 mm or less. A glass plate thickness of 2.0 mm or more provides sufficient strength for stone chip resistance, while a glass plate thickness of 5.0 mm or less prevents the glass plate from becoming too heavy, which is preferable in terms of fuel efficiency of the vehicle.

[0035] <Interlayer Film 113> The interlayer film 113 is a transparent or translucent dielectric material having dielectric properties and interposed between the glass plates 111 and 112. The glass plates 111 and 112 are bonded together by the interlayer film 113. Here, as an example, the Low-E film 115 is formed on the main surface 111B of the glass plate 111. More specifically, the interlayer film 113 bonds the Low-E film 115 and the glass plate 112 together. Examples of materials for the interlayer film 113 include thermoplastic polyvinyl butyral (PVB) and ethylene vinyl acetate copolymer (EVA). The interlayer film 113 may be transparent or colored. The interlayer film 113 may also be composed of two or more layers. In addition, the interlayer film 113 is disposed between the ceramic layer 114 and the glass plate 112 in the area where the ceramic layer 114 is present in a plan view.

[0036] <Ceramic layer 114> The ceramic layer 114 is, for example, a fired body of a dark-colored ceramic paste, and is formed by applying and firing a ceramic color paste containing a fusible glass frit containing a black pigment. The ceramic layer 114 is formed to prevent deterioration of the adhesive caused by ultraviolet rays when the vehicle antenna device 100 is adhered to the vehicle body 10, and to improve the appearance by preventing the connection portion between the vehicle antenna device 100 and the vehicle body 10 from being seen from the outside of the vehicle body 10.

[0037] As an example, the ceramic layer 114 is provided on the indoor-side surface (-Z direction side) of a Low-E film 115 provided on the indoor-side main surface 111B of the glass plate 111. In this way, the ceramic layer 114 is provided on the indoor-side main surface 111B of the glass plate 111 via the Low-E film 115. Note that, as an example, the ceramic layer 114 may be provided on the indoor-side main surface 111B of the glass plate 111. In this case, the Low-E film 115 may be provided on the indoor-side main surface 111B of the glass plate 111 in areas where the ceramic layer 114 is not present, and may be provided on the indoor-side (-Z direction) surface of the ceramic layer 114 in areas where the ceramic layer 114 is present. The ceramic layer 114 may be provided as a layer on each of the indoor-side main surfaces 111B and 112B of the glass plates 111 and 112, or may be provided only on the indoor-side main surface 112B of the glass plate 112. The ceramic layer 114 may be provided on the main surface 112A of the glass plate 112 instead of the main surface 111B or 112B. The ceramic layer 114 may be provided only on the main surface 112A of the glass plate 112. When single-layer glass is used instead of the laminated glass 110, the ceramic layer 114 is provided on the indoor-side main surface of the single-layer glass.

[0038] As an example, the ceramic layer 114 is provided on the peripheral portion of the main surface 111B of the laminated glass 110 in a plan view. The peripheral portion of the laminated glass 110 is a peripheral portion of the laminated glass 110 that is slightly inside the outer edge of the laminated glass 110 in a plan view and follows the outer edge. The peripheral portion of the laminated glass 110 is the peripheral portions of the glass sheets 111 and 112, and the outer edge of the laminated glass 110 is the outer edges of the glass sheets 111 and 112.

[0039] <Low-E Film 115> The Low-E film 115 is a film that reflects far-infrared rays and is provided to improve the heat insulating or heat blocking performance of the laminated glass 110. The Low-E film 115 is produced by, for example, forming (coating) a transparent conductive film made of tin oxide, silver, ITO, or the like on the main surface 112B of the glass plate 112. Note that the Low-E film 115 may also be, for example, a conductive film other than a transparent conductive film made of tin oxide, silver, ITO, or the like.

[0040] Here, a configuration will be described in which the Low-E film 115 is formed on the main surface 111B (second main surface) of the glass plate 111. However, the Low-E film 115 may be formed on a main surface other than the main surface 111B (second main surface), for example, on the main surface 112A (third main surface) of the glass plate 112 or the main surface 112B (fourth main surface) of the glass plate 112. When single-layer glass is used instead of the laminated glass 110, the Low-E film 115 is provided on the main surface of the single-layer glass facing the interior.

[0041] Furthermore, the main surface 112A (third main surface) of the glass plate 112 extends along the main surface 111B (second main surface) of the glass plate 111 and the main surface 112B (fourth main surface) of the glass plate 112. Therefore, forming the Low-E film 115 on the main surface 112A (third main surface) of the glass plate 112 corresponds to forming the Low-E film 115 along the main surface 111B (second main surface) of the glass plate 111 or the main surface 112B (fourth main surface) of the glass plate 112.

[0042] <Antenna Element 120> For example, the antenna element 120 is formed on the main surface 112B of the glass plate 112 of the laminated glass 110 and extends in the X direction at a position overlapping the ceramic layer 114 in a plan view. It is preferable that the antenna element 120 is not visible when the vehicle antenna device 100 is viewed from the exterior. For example, the antenna element 120 extends parallel to a portion of the inner edge of the opening 11 extending in the X direction. While FIG. 2 shows a configuration in which the antenna element 120 extends in the X direction in the X-Z cross section, the antenna element 120 may extend in a direction other than the X direction as long as it extends parallel to the inner edge of the opening 11. Furthermore, at least a portion of the antenna element 120 may be located in a region of the laminated glass 110 that does not overlap the ceramic layer 114. For example, a configuration in which at least a portion of the antenna element 120 is located inside the ceramic layer 114 provided on the peripheral edge of the laminated glass 110 is possible.

[0043] Furthermore, when the ceramic layer 114 is provided on the outdoor-side main surface 112A of the glass plate 112, the antenna element 120 may be provided between the main surface 112A and the ceramic layer 114. In other words, the antenna element 120 may be formed on the outdoor-side main surface 112A of the glass plate 112 and covered with the ceramic layer 114.

[0044] The antenna element 120 is an antenna element for a monopole antenna. The antenna element 120 is fed with power from a wireless communication device mounted on the vehicle body 10 through a feed point (not shown in FIG. 2 ). A cable connecting the feed point and the wireless communication device is preferably positioned so as to overlap the ceramic layer 114 in a plan view. The antenna element 120, together with the metal part of the vehicle body 10, uses the metal part of the vehicle body 10 as a ground plane and operates as a monopole antenna.

[0045] As an example, the antenna element 120 can be produced by applying silver paste to the main surface 112B of the glass plate 112 of the laminated glass 110 by screen printing and then firing the paste. However, the antenna element 120 is not limited to this configuration, and may be produced, for example, by forming a metal foil such as a copper foil on the main surface 112B and patterning it.

[0046] Furthermore, the antenna element 120 is not limited to being formed on the main surface 112B of the glass plate 112 of the laminated glass 110, but may also be formed on the main surface 112A of the glass plate 112 at a position that overlaps with the ceramic layer 114 in a planar view, or may be formed on the surface of the ceramic layer 114 on the -Z direction side (indoor side).

[0047] Furthermore, when the ceramic layer 114 is formed on the main surface 112A of the glass plate 112 of the laminated glass 110, the antenna element 120 may be formed on a portion of the main surface 112B that overlaps with the ceramic layer 114 in a planar view.

[0048] Furthermore, when the ceramic layer 114 is formed on the main surface 112B of the glass plate 112 of the laminated glass 110, the antenna element 120 only needs to be formed on the surface of the ceramic layer 114 facing the interior of the vehicle in a plan view.

[0049] Furthermore, when the vehicle antenna device 100 includes single-layer glass instead of laminated glass 110, the antenna element 120 may be formed on the interior surface of the ceramic layer 114 formed on the interior main surface of the single-layer glass.

[0050] The antenna element 120 is an antenna element that transmits or receives radio waves in a predetermined frequency band. The antenna element 120 may be an antenna element capable of receiving radio waves in the frequency range from the very high frequency (VHF) band to the ultra high frequency (UHF) band. Specifically, the antenna element 120 may be an antenna element capable of receiving radio waves with a frequency range from 30 MHz to 3 GHz. The antenna element 120 may also be an antenna element capable of receiving at least one of radio waves in Band III (174 MHz to 240 MHz) of DAB (Digital Audio Broadband) and radio waves of terrestrial digital television broadcast waves (470 MHz to 710 MHz), which are included in the VHF band to the UHF band. The antenna element 120 may be an antenna element capable of receiving narrowband ITS (Intelligent Transport Systems) radio waves including the AM broadcast wave frequency band (522 kHz to 1710 kHz), the FM broadcast wave frequency band (76 MHz to 108 MHz), and 760 MHz. A coil may be inserted into the antenna element 120 to miniaturize it for the FM / DAB bands, which have long wavelengths.

[0051] Furthermore, the antenna element 120 may be an antenna element capable of transmitting and receiving radio waves in the LTE (Long Term Evolution) frequency band, an antenna element capable of receiving radio waves in a satellite communication frequency band such as GNSS (Global Navigation Satellite System) and SDARS (Satellite Digital Audio Radio Service), or an antenna element capable of transmitting and receiving radio waves in the 5G (fifth generation mobile communication system) frequency band. An example of an antenna element for 5G is an antenna element capable of transmitting and receiving radio waves in a frequency band (e.g., 5.8 GHz band) for short-range communication called DSRC (Dedicated Short Range Communication) used for V2X (Vehicle to Everything) such as vehicle-to-vehicle communication and road-to-vehicle communication. Furthermore, the antenna element 120 is not limited to one of the antenna elements exemplified above, but may include multiple radiating elements and be integrated and arranged in one location, or multiple antenna elements may be individually distributed and arranged on the laminated glass 110. The antenna element 120 may include multiple antennas capable of transmitting and receiving radio waves in the same frequency band, or multiple antennas capable of transmitting and receiving radio waves in different frequency bands. A more specific configuration example of the antenna element 120 will be described later with reference to Figures 11A to 11D.

[0052] <Simulation Model> Fig. 3A is a diagram showing an example of a simulation model of a vehicle 1 including the vehicle antenna device 100 of the embodiment. Fig. 3B is a diagram showing an example of a simulation model of a comparative vehicle antenna device 50. In Fig. 3A , the +X direction is the forward direction of the vehicle 1, and the +Y direction is the left direction of the vehicle 1.

[0053] In the simulation model of the vehicle 1 including the vehicle antenna device 100 shown in Figure 3A, the vehicle body 10 is represented by a three-dimensional box-shaped housing. Hereinafter, the simulation model of the vehicle 1 including the vehicle antenna device 100 shown in Figure 3A will be referred to as the simulation model of the embodiment. Also, below, the simulation model including the comparative vehicle antenna device 50 and metal plate 51 shown in Figure 3B will be referred to as the comparative simulation model. Note that in both the simulation model of the embodiment and the comparative simulation model, the laminated glass 110 is tempered glass having a thickness of 3.1 mm, and is fixed to the opening 11 with a urethane adhesive 20 having a thickness of 5 mm.

[0054] In the simulation model of the embodiment, the vehicle body 10 is made of a perfect conductor (PEC), for example. The vehicle body 10 has an opening 11 in the roof, openings 12 on the left and right sides, an opening 13F for a windshield, and an opening 13R for a rear window. There are two openings 12 on each side of the vehicle body 10 in the front-rear direction, corresponding to the front side window and the rear side window.

[0055] In FIG. 3A, D shown for the opening 11 is the distance from the center of the width of the opening 11 in the Y direction to the antenna element 120.

[0056] 3A, Ws shown for the left opening 12 is the width in the front-to-rear direction of the left opening 12, and Hs is the height (length in the height direction) of the left opening 12. The width Ws and height Hs also apply to the right opening 12.

[0057] 3A, Wf shown for the windshield opening 13F is the width in the left-right direction of the opening 13F, and Hf is the height (length in the height direction) of the opening 13F. Also, Wr shown for the rear side window opening 13R is the width in the left-right direction of the opening 13R, and Hr is the height (length in the height direction) of the opening 13R.

[0058] A comparative vehicle antenna device 50 shown in Fig. 3B includes a laminated glass 110 and an antenna element 120, similar to the vehicle antenna device 100 of the embodiment, but is not provided on the three-dimensional vehicle body 10, but is provided in an opening 52 provided in a flat metal plate 51. The metal plate 51 shown in Fig. 3B has the same size as the roof portion of the vehicle body 10 shown in Fig. 3A and is made of a perfect conductor (PEC). The size of the opening 52 shown in Fig. 3B is equal to the size of the opening 11 shown in Fig. 3A.

[0059] 3B, D shown for the opening 52 is the distance from the center of the width of the opening 52 in the Y direction to the antenna element 120. The distance D shown in FIG. 3B corresponds to the distance D shown in FIG. 3A.

[0060] In the simulation model of the embodiment shown in FIG. 3A, antenna element 120 is a single linear element, and as an example, extends in the +X direction from near the corner on the +Y direction side on the −X direction side of the inner edge of rectangular opening 11, parallel to the part of the inner edge of opening 11 on the +Y direction side that extends in the X direction.

[0061] Similarly, in the comparative simulation model shown in Fig. 3B, antenna element 120 is a single linear element, and as an example, extends in the +X direction from near the corner on the +Y direction side on the -X direction side of the inner edge of rectangular opening 52, parallel to the part of the inner edge of opening 52 extending in the X direction on the +Y direction side. Note that the lengths of antenna elements 120 shown in Fig. 3A and Fig. 3B are the same, and other conditions are also the same.

[0062] <Simulation Results of Gain Frequency Characteristics> Fig. 4 is a diagram showing an example of simulation results of the frequency characteristics of the gain of the antenna element 120 when radio waves are emitted from the antenna element 120. Fig. 4 shows an example of calculation results for the antenna element 120 of the simulation model of the embodiment (see Fig. 3A) and the comparative simulation model (see Fig. 3B).

[0063] Here, an electromagnetic field simulator was used to calculate the frequency characteristics of gain when horizontally polarized and vertically polarized radio waves were emitted in two simulation models.

[0064] Good values ​​were obtained for the horizontally polarized antenna gain in both the comparative simulation model and the simulation model of the embodiment. In particular, the horizontally polarized antenna gain of the comparative simulation model was approximately -6 dB to approximately -7 dB, which was better than the horizontally polarized antenna gain of the simulation model of the embodiment (approximately -13 dB to approximately -14 dB). However, the horizontally polarized antenna gain of the simulation model of the embodiment was also sufficiently good.

[0065] The gain of the vertically polarized antenna in the comparative simulation model was low at about -38 dB to about -40 dB, but the gain of the simulation model of the embodiment was about -3.5 dB to about -10 dB, which was a very good value. The gain of the vertically polarized antenna in the simulation model of the embodiment was a very good value compared to the gain of the horizontally polarized antenna in the comparative simulation model.

[0066] This difference is thought to arise from the fact that the simulation model of the embodiment is configured such that the vehicle antenna device 100 of the embodiment is provided in an opening 11 in the roof of the three-dimensional vehicle body 10, compared to a configuration in which the comparative vehicle antenna device 50 is provided in an opening 52 in a flat metal plate 51 as in the comparative simulation.

[0067] The vehicle antenna device 100 of the embodiment has a configuration including an antenna element 120 arranged in an XY plane parallel to the horizontal plane, and has good antenna gain for vertical polarization. Furthermore, the vehicle antenna device 100 of the embodiment also has good antenna gain for horizontal polarization because it includes an antenna element 120 arranged in an XY plane parallel to the horizontal plane.

[0068] The following will consider the fact that the vehicle antenna device 100 is capable of transmitting and receiving vertically polarized radio waves, even though it has a configuration including the antenna element 120 arranged in an XY plane parallel to the horizontal plane.

[0069] <Simulation results of electric field distribution> Here, we will mainly consider vertically polarized radio waves using a simulation model of the embodiment including the vehicle antenna device 100 and a comparison simulation model including a comparative vehicle antenna device 50.

[0070] <Simulation Results of the Comparative Simulation Model> Figure 5A shows the electric field distribution of radio waves radiated from the antenna element 120 of the comparative simulation model (see Figure 3B). The simulation of the electric field distribution was performed using an electromagnetic field simulator, with the frequency of the radio waves radiated from the antenna element 120 set to 93 MHz, as an example. 93 MHz is a frequency included in the frequency band of FM broadcast waves. In Figure 5A, the direction of the arrow indicating the electric field distribution represents the direction of the electric field, and the brightness of the arrow represents the strength of the electric field. The higher the strength of the electric field, the higher the brightness of the arrow.

[0071] 5A shows the electric field distribution in the YZ cross section of a comparative simulation model. Antenna element 120 extends parallel to the side extending in the X direction on the +Y direction side of the inner edge of opening 52. The position in the X direction of the YZ cross section shown in FIG. 5A is the center of the X direction length of opening 52.

[0072] Among the many arrows showing the electric field distribution in Figure 5A, the comparative vehicle antenna device 50, metal plate 51, and laminated glass 110 are shown extending in the Y direction. Of the three double-headed arrows shown below the many arrows, the central double-headed arrow indicates the section in the Y direction where the comparative vehicle antenna device 50 is located. The feed point of the antenna element 120 is located on the +Y direction side of the comparative vehicle antenna device 50, and the antenna element 120 extends in the X direction at the position of the feed point. Of the three double-headed arrows, the two double-headed arrows at both ends indicate the section in the Y direction where the metal plate 51 is located.

[0073] In Fig. 5A, the electric field distribution is approximately symmetrical above and below the comparative vehicle antenna device 50, and the vertical components of the electric field are canceled out. Null points are present to the right and left of the feed point. This cancellation of the vertical components is thought to be the reason why the gain of the vertically polarized radio wave in the comparative simulation model was low in the simulation results shown in Fig. 4.

[0074] <Simulation Results of Simulation Model of Embodiment> Fig. 5B shows the electric field distribution of radio waves radiated from antenna element 120 of the simulation model of the embodiment (see Fig. 3A). As an example, the simulation of the electric field distribution was performed by setting the frequency of the radio waves radiated from antenna element 120 to 93 MHz. The direction of the arrow indicating the electric field distribution represents the direction of the electric field, and the brightness of the arrow represents the strength of the electric field. The higher the strength of the electric field, the higher the brightness.

[0075] Among the many arrows showing the electric field distribution in Figure 5B, a YZ cross section of the vehicle body 10 is shown. Figure 5B also shows the vehicle antenna device 100 installed in the opening 11 in the roof of the vehicle body 10, and the metal plate portions of the roof on both sides of the opening 11. Of the three double-headed arrows shown below the many arrows, the central double-headed arrow indicates the section in the Y direction where the vehicle antenna device 100 is located within the opening 11. The feed point is located in the +Y direction side of the vehicle antenna device 100, and the antenna element 120 extends in the X direction at the position of the feed point. Of the three double-headed arrows, the two double-headed arrows at both ends indicate the section where the metal plate portions of the roof located on both sides of the opening 11 are located.

[0076] The position in the X direction of the YZ cross section shown in Fig. 5B is the center of the X direction length of the opening 11. Fig. 5B shows the YZ cross section when viewing the vehicle body 10 from the front side to the rear side, so the +Y direction side is the left side of the vehicle body 10 and the -Y direction side is the right side of the vehicle body 10.

[0077] 5B also shows openings 12 on the +Y and −Y direction sides corresponding to the left and right front side windows of the vehicle body 10. The section in which the openings 12 are located in the Z direction is indicated by a double-headed arrow on the left side of the multiple arrows.

[0078] In Figure 5B, the electric field distribution is asymmetric above and below the vehicle antenna device 100. In particular, the electric field distribution around the opening 12 provided on the +Y direction side (left side) closer to the power feeder is different from the electric field distribution above the vehicle antenna device 100 and the roof. For this reason, it is thought that a downward electric field is obtained around the opening 12 provided on the +Y direction side (left side) closer to the power feeder. Also, in Figure 5B, a downward electric field is generated on the left side and an upward electric field is generated on the right side, making the left and right electric fields asymmetric above and below, and the generation of a null is suppressed.

[0079] From the simulation results shown in Figures 5A and 5B as described above, it was confirmed that in the simulation model of the embodiment, the presence of opening 12 for the front side window on the side of vehicle body 10 adjacent to opening 11 in the roof of vehicle body 10 prevents the vertical component of the electric field from being canceled out, and therefore vertically polarized radio waves can be received by antenna element 120 parallel to the XY plane.

[0080] In this way, it is the opening 12 provided on the side of the vehicle body 10 and adjacent to the roof opening 11 that contributes to the reception of vertically polarized radio waves. "Opening 12 adjacent to opening 11" means that, among the openings 12 on the side of the vehicle body 10, the opening contributes to generating a vertical electric field in the electric field distribution shown in Fig. 5B. Therefore, for example, as shown in Fig. 3A, if the roof opening 11 is located on the front side of the roof, opening 12 for a front side window may be provided on the side of the vehicle body 10 and be the opening 12 adjacent to the roof opening 11.

[0081] 3A , if the roof opening 11 is located in front of the roof, even if there is no overlapping section between the roof opening 11 and the opening 12 in the rear side window or the rear quarter window in the X direction (the fore-and-aft direction of the vehicle body 10), as long as it contributes to generating a vertical electric field, it will be considered adjacent to the opening 11. Also, if the roof opening 11 is located behind the roof, even if there is no overlapping section between the roof opening 11 and the opening 12 in the front side window or the front quarter window in the X direction (the fore-and-aft direction of the vehicle body 10), it will be considered adjacent to the opening 11 as long as it contributes to generating a vertical electric field.

[0082] Furthermore, since the antenna element 120 can receive radio waves by performing the reverse operation to transmitting the radio waves, in the simulation model of the embodiment, the antenna element 120 parallel to the XY plane can receive vertically polarized radio waves.

[0083] <Definition of Width and Height of Opening in Vehicle Body 10> Fig. 6 is a diagram illustrating an example of the definition of the width and height of the opening in the vehicle body 10. The opening in the vehicle body 10 is, for example, the openings 11, 12, 13R, and 13F described above. Here, the opening 12 corresponding to the front side window will be used as an example for explanation.

[0084] As described above, from the simulation results shown in Figures 5A and 5B, it was found that in the simulation model of the embodiment, the presence of the side opening 12 adjacent to the opening 11 in the roof of the vehicle body 10 makes it possible to radiate vertically polarized radio waves from the antenna element 120 parallel to the XY plane.

[0085] Since the opening 12 on the side adjacent to the opening 11 in the roof of the vehicle body 10 is thought to affect the radiation characteristics of radio waves, in the simulations below, the definitions of width W and height H will be explained assuming that the opening 12 is an opening that allows radio waves to pass through.

[0086] Here, as an example, the method of defining the horizontal width W and vertical height H of the metal part of the car body 10 at the opening through which radio waves pass is defined as follows.

[0087] For example, if the opening is an opening 12 corresponding to a front side window, and the door of the vehicle body 10 has a window frame, the opening is the portion surrounded by the belt line and the window frame. Also, if the door of the vehicle body 10 does not have a window frame, the opening is the portion where the belt line and the metal portion of the A-pillar, B-pillar, or C-pillar of the vehicle body 10 surround the window.

[0088] Therefore, as an example, the method of defining the horizontal width W and vertical height H of the metal part of the vehicle body 10 at the opening through which radio waves pass is defined as follows: As shown in Figure 6, a rectangle inscribed in the opening 12 is determined, and the length of the horizontal side of the rectangle projected onto the XZ plane as seen from the side of the vehicle body 10 is defined as the width W, and the length of the vertical side is defined as the height H.

[0089] While the description here has been given using the opening 12 corresponding to the front side window, the same applies to the openings 11, 13R, and 13F. For the opening 11, a rectangle inscribed with the opening surrounded by the metal portion of the vehicle body 10 is determined, and the length of the front-to-rear side of the rectangle is defined as the length of the opening 11, and the length of the horizontal side is defined as the width. For the openings 13R and 13F, a rectangle inscribed with the opening surrounded by the metal portion of the vehicle body 10 is determined, and the length of the horizontal side of the rectangle is defined as the width W of the openings 13R and 13F, and the length of the vertical side is defined as the height H.

[0090] <Simulation Results of Average Gain of Antenna Element 120 with Respect to Distance D> Fig. 7 is a diagram showing an example of simulation results of the average gain of the antenna element 120 with respect to the distance D. Fig. 7 shows calculation results for a comparative simulation model (see Fig. 3B) and a simulation model of the embodiment (see Fig. 3A). The average gain of the antenna element 120 is the average gain of the antenna element 120 at five frequencies: 88 MHz, 93 MHz, 98 MHz, 103 MHz, and 108 MHz.

[0091] 3A and 3B , it is assumed that antenna element 120 extends parallel to a portion of the inner edge of openings 11 and 52 extending in the X direction on the +Y direction side. The position where distance D is 0 mm indicates that antenna element 120 is located at the center of the Y direction width of openings 11 and 52. The Y direction width of openings 11 and 52 is 1000 mm, and the position where distance D is 500 mm corresponds to the portion of the inner edge of openings 11 and 52 extending in the X direction on the +Y direction side.

[0092] Here, an electromagnetic field simulator was used to calculate the average gains of horizontally polarized waves and vertically polarized waves in two simulation models.

[0093] Good values ​​were obtained for the average gain of horizontal polarization in both the comparative simulation model and the simulation model of the embodiment, and there was little dependence on the distance D, but there was a tendency for it to decrease when the distance D exceeded 400 mm.

[0094] The average gain of vertically polarized waves in the comparative simulation model was low at approximately -38 dB to approximately -44 dB, and tended to increase as the distance D increased. The simulation model of the embodiment showed very good values ​​at approximately -11 dB to approximately -13 dB, and tended to decrease when the distance D exceeded 400 mm.

[0095] The average gain of horizontally polarized waves for the comparative simulation model (see Figure 3B) and the simulation model of the embodiment (see Figure 3A) decreased when the distance D exceeded 400 mm, indicating that the average gain decreases when the antenna element 120 is placed too close to the inner edges of the openings 11 and 52.

[0096] Furthermore, the average gain of the vertically polarized wave for the simulation model of the embodiment (see Figure 3A) decreased when the distance D exceeded 400 mm, and it was therefore found that the average gain decreased when the antenna element 120 was placed too close to the inner edges of the openings 11 and 52.

[0097] <Simulation Results of Average Gain of Antenna Element 120 with Respect to Width Ws of Opening 12> Figure 8A is a diagram showing an example of simulation results of the average gain of the antenna element 120 with respect to the width Ws of the opening 12. Here, an example of calculation results of the average gain of the antenna element 120 when the width Ws of the opening 12 is changed in the simulation model of the embodiment (see Figure 3A) will be described. Note that the width Ws of the opening 12 refers to the width Ws of four openings 12 where the left and right front side windows and rear side windows of the vehicle body 10 are provided, and the widths Ws of all four openings 12 were set to the same value. In addition, the heights Hs of all four openings 12 were also set to the same value.

[0098] As an example, the average gain of antenna element 120 is calculated at five frequencies, 88 MHz, 93 MHz, 98 MHz, 103 MHz, and 108 MHz, of the radio waves radiated by antenna element 120. Fig. 8A also shows the average gain when the height Hs of opening 12 is set to 11 values ​​from 0.016 to 0.310.

[0099] In Figure 8A, the horizontal axis represents the width Ws normalized by the wavelength of a 98 MHz radio wave in free space. If the wavelength of a radio wave in free space is λ, then 0.25 corresponds to λ / 4. The vertical axis represents the average gain (dB).

[0100] The same tendency was observed for all heights Hs, and the average gain of the antenna element 120 tended to be maximum when the width Ws was in the range of approximately 0.17 to approximately 0.23.

[0101] Furthermore, when the width Ws is set to the lower limit at a practical average sensitivity of -6.5 dB, it is found from the characteristics in Figure 8A that the lower limit of the width Ws is 0.05. A width Ws of 0.05 corresponds to 150 mm for FM radio waves and 73 mm for DAB radio waves.

[0102] <Simulation Results of Average Gain of Antenna Element 120 with Respect to Height Hs of Opening 12> Fig. 8B is a diagram showing an example of simulation results of the average gain of the antenna element 120 with respect to the height Hs of the opening 12. Here, an example of calculation results of the average gain of the antenna element 120 when the height Hs of the opening 12 is changed in the simulation model of the embodiment (see Fig. 3A) will be described.

[0103] As an example, the average gain of antenna element 120 is calculated at five frequencies, 88 MHz, 93 MHz, 98 MHz, 103 MHz, and 108 MHz, of the radio waves radiated by antenna element 120. Fig. 8B also shows the average gain when the width Ws of opening 12 is set to six values ​​from 0.033 to 0.278.

[0104] In Figure 8B, the horizontal axis represents the height Hs normalized by the wavelength of a 98 MHz radio wave in free space. If the wavelength of the radio wave in free space is λ, then 0.25 corresponds to λ / 4. The vertical axis represents the average gain (dB).

[0105] The same tendency was observed for all widths Ws, with the average gain of the antenna element 120 tending to be greatest at a height Hs of approximately 0.05. The average gain of the antenna element 120 dropped sharply when the height Hs was approximately 0.01 or less, and also decreased when the height Hs exceeded approximately 0.20. This confirmed that a height Hs in the range of 0.01 to 0.20 was favorable. Note that an Hs of 0.01 corresponds to a height Hs of 30 mm, and an Hs of 0.20 corresponds to a height Hs of 612 mm.

[0106] <Simulation Results of Average Gain of Antenna Element 120 with Respect to Width Wr of Rear Windshield Opening 13R> Fig. 9A is a diagram showing an example of simulation results of the average gain of antenna element 120 with respect to width Wr of rear windshield opening 13R. Fig. 9A shows the results of calculations performed while changing width Wr in the simulation model of the embodiment (see Fig. 3A ).

[0107] The average gain of the antenna element 120 is, for example, the average gain calculated at five frequencies of vertically polarized radio waves radiated by the antenna element 120: 88 MHz, 93 MHz, 98 MHz, 103 MHz, and 108 MHz.

[0108] Here, it is assumed that the antenna element 120 extends parallel to the portion of the inner edge of the openings 11 and 52 on the +Y direction side, which extends in the X direction, as shown in FIGS. 3A and 3B.

[0109] The average gain of the vertically polarized antenna element 120 increases when the width Wr is in the range of approximately 1000 mm to approximately 1200 mm, reaching a maximum value (approximately -4 dB) at approximately 1100 mm, and even around that, it is around -5 dB in the range of 100 mm to 1400 mm, with no significant fluctuations observed.

[0110] It covers the width of the rear window of a typical vehicle, and we were able to confirm that it can be used for a variety of vehicle models.

[0111] <Simulation Results of Average Gain of Antenna Element 120 vs. Width Wf of Windshield Opening 13F> Fig. 9B is a diagram showing an example of simulation results of the average gain of antenna element 120 vs. width Wf of windshield opening 13F. Fig. 9B shows the results of calculations performed while changing width Wf in the simulation model of the embodiment (see Fig. 3A ).

[0112] The average gain of the antenna element 120 is, for example, the average gain calculated at five frequencies of vertically polarized radio waves radiated by the antenna element 120: 88 MHz, 93 MHz, 98 MHz, 103 MHz, and 108 MHz.

[0113] Here, it is assumed that the antenna element 120 extends parallel to the portion of the inner edge of the openings 11 and 52 on the +Y direction side, which extends in the X direction, as shown in FIGS. 3A and 3B.

[0114] The average gain of the vertically polarized radio wave was approximately constant at about -6 dB within the width Wf range of 100 mm to 1400 mm, and no large fluctuations were observed.

[0115] It covers the width of windshields of common vehicles, and we were able to confirm that it can be used for a variety of vehicle models.

[0116] <Simulation Results of Average Gain of Antenna Element 120 for Width Wf of Windshield Opening 13F and Width Wr of Rear Windshield Opening 13R> Fig. 9C is a diagram showing an example of simulation results of the average gain of antenna element 120 for width Wf of windshield opening 13F and width Wr of rear windshield opening 13R. Fig. 9C shows calculation results when the widths Wf and Wr are changed while being set to the same values ​​in the simulation model of the embodiment (see Fig. 3A ).

[0117] The average gain of the antenna element 120 is, for example, the average gain calculated at five frequencies of vertically polarized radio waves radiated by the antenna element 120: 88 MHz, 93 MHz, 98 MHz, 103 MHz, and 108 MHz.

[0118] Here, it is assumed that the antenna element 120 extends parallel to the portion of the inner edge of the openings 11 and 52 on the +Y direction side, which extends in the X direction, as shown in FIGS. 3A and 3B.

[0119] The average gain of antenna element 120 for vertical polarization increased when widths Wf and Wr were in the range of approximately 1000 mm to approximately 1200 mm, reaching a maximum value (approximately -4 dB) at approximately 1100 mm, and did not fluctuate significantly even around this range, remaining around -5 dB in the range of 100 mm to 1400 mm. This was approximately the same as the result obtained when the width Wr of rear window opening 13R shown in Figure 9A was changed.

[0120] It covers the width of windshields and rear windows of common vehicles, and we were able to confirm that it can be used for a variety of vehicle models.

[0121] <Simulation results of the average gain of the antenna element 120 for the width Wf of the windshield opening 13F and the width Wr of the rear window opening 13R> Figure 9D is a diagram showing an example of the simulation results of the average gain of the antenna element 120 for the width Wf of the windshield opening 13F and the width Wr of the rear window opening 13R.

[0122] FIG. 9D shows a simulation result in which antenna element 120 extends parallel to the side of the inner edge of opening 52 on the −X direction side extending in the Y direction, unlike the extending direction in FIG. 3B.

[0123] The average gain of the antenna element 120 is, for example, the average gain calculated at five frequencies of vertically polarized radio waves radiated by the antenna element 120: 88 MHz, 93 MHz, 98 MHz, 103 MHz, and 108 MHz.

[0124] FIG. 9D shows the results of calculations performed in the simulation model of the embodiment (see FIG. 3A) when the widths Wf and Wr are set to the same value but are changed.

[0125] The average gain of the vertically polarized radio wave was approximately constant at about -6.5 (dB) within the range of widths Wf and Wr from 100 mm to 1400 mm, with almost no fluctuations observed.

[0126] <Simulation Results of Average Gain of Antenna Element 120 with Respect to Vehicle Width> Fig. 9E is a diagram showing an example of simulation results of the average gain of the antenna element 120 with respect to the vehicle width. The vehicle width is the width of the vehicle body 10 in the Y direction.

[0127] The average gain of the antenna element 120 is, for example, the average gain calculated at five frequencies of vertically polarized radio waves radiated by the antenna element 120: 88 MHz, 93 MHz, 98 MHz, 103 MHz, and 108 MHz.

[0128] 9E shows the results of calculations performed on the simulation model of the embodiment (see FIG. 3A) when the vehicle width is changed from 1000 mm to 2000 mm. Note that when the vehicle width is changed, the widths Ws, Wf, and Wr also change.

[0129] Here, it is assumed that the antenna element 120 extends parallel to the portion of the inner edge of the openings 11 and 52 on the +Y direction side, which extends in the X direction, as shown in FIGS. 3A and 3B.

[0130] The average gain of the vertically polarized antenna element 120 varied from approximately −5.5 dB to approximately −10.5 dB as the vehicle width varied between 1000 mm and 2000 mm, reaching a maximum value (approximately −5.5 dB) at approximately 1350 mm and a minimum value (approximately −10.5 dB) at approximately 1800 mm.

[0131] Although the average gain of the vertically polarized antenna element 120 varies with the vehicle width, it was confirmed that it covers the width of common vehicles and is compatible with a variety of vehicle types.

[0132] <Principle of how the horizontal length of the opening 12 affects the average gain of vertically polarized radio waves> For vertically polarized radio waves, when the width W of the opening 12 is short, the potentials generated at the upper and lower edges of the opening 12 that receive the vertically polarized radio waves become close to each other, and the radio waves are significantly attenuated as they penetrate into the body (metal plate), and no longer cancel out the radio waves propagating from outside the vehicle. This improves the receiving sensitivity of the vertically polarized waves. When the width W of the opening 12 is long, the potential difference generated at the upper and lower edges of the opening 12 increases, and more radio waves enter the vehicle interior. This causes the radio waves that enter the vehicle interior to cancel out the radio waves propagating from outside the vehicle, resulting in a decrease in the receiving sensitivity of the vertically polarized waves.

[0133] For horizontally polarized radio waves, if the height H of the opening 12 is short, they are reflected by the equipotential surface of the body and do not penetrate inside. However, if the height H of the opening 12 is long, the amount of radio waves that penetrate inside the body increases, similar to the behavior of vertically polarized waves, but because the directions of the radio waves propagating outside and inside the vehicle reinforce each other, as with vertically polarized waves, the receiving sensitivity of horizontally polarized waves increases, contrary to the tendency of vertically polarized waves.

[0134] <Dimensions of opening required for the average gain of antenna element 120 to be −7 dB or more> Fig. 10 is a characteristics diagram showing an example of dimensions of the opening required for the average gain of antenna element 120 to be −7 dB or more. The horizontal axis of Fig. 10 represents the width Ws (mm) of opening 12, and the vertical axis represents the height Hs (mm) of opening 12.

[0135] The lower limit of the height Hs is 0.01, which is the lower limit of the preferred range of the height Hs in FIG. 8B . A height Hs of 0.01 corresponds to 30 mm for FM radio waves and 15 mm for DAB radio waves. The upper limit of the height Hs in FIG. 10 is 0.25, at which the height Hs and width Ws are equal. A height Hs of 0.25 corresponds to 750 mm for FM radio waves and 365 mm for DAB radio waves. Furthermore, a width Ws of 0.25 corresponds to 750 mm for FM radio waves and 365 mm for DAB radio waves. The upper limit of the height Hs (0.25) obtained in FIG. 10 was greater than the upper limit of the height Hs (0.20) obtained from the characteristics in FIG. 8B .

[0136] 11A to 11D are diagrams illustrating examples of variations of the antenna element 120. Each of Fig. 11A to 11D shows the laminated glass 110 and the antenna element 120 of the vehicle antenna device 100, as well as XYZ coordinates. As an example, the +X direction is the forward direction of the vehicle 1, and the +Y direction is the leftward direction of the vehicle 1.

[0137] Furthermore, antenna element 120 has first radiating element 120A, second radiating element 120B, and power feeding portion 121. Here, as an example, a configuration in which antenna element 120 receives radio waves will be described, but antenna element 120 may also be configured to transmit radio waves.

[0138] 11A, the power supply part 121 is provided in the center in the Y direction of the end part on the −X direction side of the laminated glass 110, and the first radiating element 120A and the second radiating element 120B extend in the +Y direction and the −Y direction, respectively, from the power supply part 121. As an example, the length of the first radiating element 120A is 405 mm, and the length of the second radiating element 120B is 445 mm.

[0139] In the antenna element 120 shown in Figure 11B, the power supply portion 121 is provided at a corner on the -X direction side and the +Y direction side of the laminated glass 110, and the first radiating element 120A extends in the -Y direction from the power supply portion 121. The second radiating element 120B extends in the -Y direction together with the first radiating element 120A, then branches off from the first radiating element 120A, bends in the -X direction, and bends again in the -Y direction, extending again in the -Y direction. As an example, the length of the first radiating element 120A is 690 mm (50 mm + 640 mm), and the length of the second radiating element 120B is 450 mm (50 mm + 400 mm). The length of the common section of the first radiating element 120A and the second radiating element 120B is 50 mm.

[0140] 11C , the power supply portion 121 is provided at a corner on the −X direction side and the +Y direction side of the laminated glass 110, and the first radiating element 120A extends in the −Y direction from the power supply portion 121. The second radiating element 120B extends in the +X direction from the power supply portion 121, then bends in the −Y direction, and continues extending in the −Y direction. As an example, the length of the first radiating element 120A is 350 mm, and the length of the second radiating element 120B is 600 mm (150 mm + 450 mm).

[0141] 11D, the power feeding portion 121 is provided at a corner on the −X direction side and the +Y direction side of the laminated glass 110, and the first radiating element 120A extends in the −Y direction from the power feeding portion 121. The second radiating element 120B extends in the +X direction from the power feeding portion 121. As an example, the length of the first radiating element 120A is 900 mm, and the length of the second radiating element 120B is 600 mm.

[0142] As shown in FIGS. 11A to 11D, the first radiating element 120A and the second radiating element 120B have different lengths, allowing the antenna element 120 to receive radio waves of various FM channels and radio waves other than FM.

[0143] 11A to 11D , the configuration of the antenna element 120 is not limited to the configurations shown in Fig. 11A to 11D. In addition, when the antenna element 120 is configured with one radiating element, the one radiating element that configures the antenna element 120 is a first radiating element.

[0144] <Effects> The vehicle antenna device 100 is attached to a vehicle body 10 having an opening 11 (first opening) provided in a first metal member on the roof portion of the vehicle body 10 and an opening 12 (second opening) provided in a second metal member on a side of the vehicle body 10 and adjacent to the opening 11, and includes a laminated glass 110 (dielectric substrate) provided in the opening 11, and an antenna element 120 for a monopole antenna formed on a main surface of the laminated glass 110 facing the interior of the vehicle, the antenna element 120 including a first radiating element 120A extending parallel to the inner edge of the opening 11. Therefore, the antenna element 120 and the metal portion of the vehicle body 10 serving as a ground plane function as a monopole antenna to enable communication, and the antenna element 120 is provided on the main surface of the laminated glass 110 facing the interior of the vehicle, and does not protrude from the vehicle body 10. Furthermore, if the wavelength in free space of the radio waves transmitted or received by antenna element 120 is λ, the horizontal length of opening 12 may be 0.05λ or more and 0.25λ or less when viewed from the front of opening 12. It is preferably 0.06λ or more and 0.25λ or less, more preferably 0.07λ or more and 0.25λ or less, and even more preferably 0.08λ or more and 0.25λ or less. By setting the horizontal length of opening 12 to a value within this range, a good average gain of antenna element 120 can be obtained.

[0145] Therefore, it is possible to provide a good-looking vehicle antenna device 100. Furthermore, the antenna element 120 provided on the laminated glass 110 can transmit and receive horizontally polarized and vertically polarized radio waves, and in particular, even if the antenna element 120 is arranged parallel to a horizontal plane, it can transmit and receive vertically polarized radio waves.

[0146] The antenna element 120 may further include a second radiating element 120B extending parallel to the inner edge of the opening 11. By including the second radiating element 120B that does not protrude from the vehicle body 10, it is possible to provide a vehicle antenna device 100 that has a good appearance and enhanced transmission and reception sensitivity.

[0147] Furthermore, the extending direction of the first radiating element 120A and the extending direction of the second radiating element 120B may be different from each other, which can further enhance the sensitivity of transmission and reception.

[0148] Furthermore, the length of the first radiating element 120A and the length of the second radiating element 120B may be different from each other, thereby providing a vehicle antenna device 100 with a wider transmittable and receiveable band.

[0149] The laminated glass 110 may further include a ceramic layer 114 (shielding layer) formed on the main surface facing the interior of the vehicle, and the antenna element 120 may be formed on the surface of the ceramic layer 114 facing the interior of the vehicle in a plan view. When viewed from the exterior, the antenna element 120 is hidden by the ceramic layer 114, further improving the appearance.

[0150] Furthermore, at least a portion of the antenna element 120 may be located in a region of the laminated glass 110 that does not overlap with the ceramic layer 114. It is also possible to realize a configuration in which at least a portion of the antenna element 120 is located inside the ceramic layer 114 provided on the peripheral edge of the laminated glass 110.

[0151] The dielectric substrate may be made of tempered glass, which can provide a vehicle antenna device 100 with a good appearance.

[0152] The laminated glass 110 is a laminated glass including a glass plate 111 (first glass plate) having a main surface 111A (first main surface) on the outside of the vehicle cabin and a main surface 111B (second main surface) on the inside of the vehicle cabin, a glass plate 112 (second glass plate) located closer to the inside of the vehicle cabin than the glass plate 111 and having a main surface 112A (third main surface) on the outside of the vehicle cabin and a main surface 112B (fourth main surface) on the inside of the vehicle cabin, and an intermediate film 113 provided between the glass plate 111 and the glass plate 112, and further including a ceramic layer 114 formed on the main surface 111B, the main surface 112A, or the main surface 112B. When ceramic layer 114 is formed on main surface 111B, antenna element 120 is formed on the surface of ceramic layer 114 facing the interior of the vehicle in a plan view, or on a portion of main surface 112A or main surface 112B that overlaps with ceramic layer 114 in a plan view, and when ceramic layer 114 is formed on main surface 112A, antenna element 120 may be formed on a portion of main surface 112B that overlaps with ceramic layer 114 in a plan view, or when ceramic layer 114 is formed on main surface 112B, antenna element 120 may be formed on the surface of ceramic layer 114 facing the interior of the vehicle in a plan view. The vehicle antenna device 100 includes laminated glass 110 as a dielectric substrate, and when viewed from the exterior, antenna element 120 is concealed by ceramic layer 114, making it possible to provide a vehicle antenna device with a better appearance.

[0153] Furthermore, if the wavelength of radio waves in free space is λ, the vertical length of opening 12 may be 0.01λ or more and 0.20λ or less when viewed from the front of opening 12. By setting the vertical length of opening 12 to a value within this range, a good average gain of antenna element 120 can be obtained.

[0154] The vehicle 1 includes a vehicle body 10 and a vehicle antenna device 100, the vehicle body 10 having an opening 11 provided in a first metal member of the roof portion and an opening 12 provided in a second metal member of the side portion adjacent to the opening 11, the vehicle antenna device 100 having a laminated glass 110 provided in the opening 11 and an antenna element 120 for a monopole antenna formed on a main surface of the laminated glass 110 on the interior side of the vehicle, the antenna element 120 including a first radiating element 120A extending parallel to the inner edge of the opening 11. Therefore, the antenna element 120 and the metal portion of the vehicle body 10, which is a ground plane, function as a monopole antenna to enable communication, and the antenna element 120 is provided on the main surface of the laminated glass 110 on the interior side of the vehicle, and does not protrude from the vehicle body 10.

[0155] Therefore, a vehicle 1 with a good appearance can be provided.

[0156] The above describes an exemplary vehicle antenna device and vehicle of the present disclosure, but the present disclosure is not limited to the specifically disclosed embodiments, and various modifications and variations are possible without departing from the scope of the claims.

[0157] This international application claims priority based on Japanese Patent Application No. 2023-220277, filed on December 27, 2023, the entire contents of which are incorporated herein by reference.

[0158] DESCRIPTION OF SYMBOLS 1 Vehicle 10 Vehicle body 11, 12, 13F, 13R Opening 11A Flange 100 Vehicle antenna device 110 Laminated glass 111 Glass plate (an example of a first glass plate) 111A Main surface (an example of a first main surface) 111B Main surface (an example of a second main surface) 112 Glass plate (an example of a second glass plate) 112A Main surface (an example of a third main surface) 112B Main surface (an example of a fourth main surface) 113 Intermediate film 114 Ceramic layer (an example of a shielding layer) 115 Low-E film (an example of a conductive film) 120 Antenna element 120A First radiating element 120B Second radiating element 121 Power supply section

Claims

1. A vehicle antenna device attached to a vehicle having a first opening provided in a first metal member of a roof portion of a vehicle body and a second opening provided in a second metal member of a side portion of the vehicle body and adjacent to the first opening, a dielectric substrate provided in the first opening, and an antenna element for a monopole antenna formed on a main surface on the vehicle interior side of the dielectric substrate, the antenna element including a first radiation element extending parallel to an inner edge of the first opening, wherein when a wavelength in free space of radio waves transmitted or received by the antenna element is λ, in a front view of the second opening, a lateral length of the second opening is 0.05λ or more and 0.25λ or less.

2. The vehicle antenna device according to claim 1, wherein the antenna element further includes a second radiation element extending parallel to an inner edge of the first opening.

3. The vehicle antenna device according to claim 2, wherein a direction in which the first radiation element extends and a direction in which the second radiation element extends are different from each other.

4. The vehicle antenna device according to claim 2, wherein a length of the first radiation element and a length of the second radiation element are different from each other.

5. The vehicle antenna device according to any one of claims 1 to 4, further including a shielding layer formed on a main surface on the vehicle interior side of the dielectric substrate, wherein the antenna element is formed on a surface on the vehicle interior side of the shielding layer in a plan view.

6. The vehicle antenna device according to claim 5, wherein at least a part of the antenna element is located in a region of the dielectric substrate that does not overlap with the shielding layer.

7. The vehicle antenna device according to any one of claims 1 to 6, wherein the dielectric substrate is tempered glass.

8. The dielectric substrate includes a first glass plate having a first main surface on the outside of the vehicle cabin and a second main surface on the inside of the vehicle cabin, a second glass plate located on the inside of the vehicle cabin with respect to the first glass plate and having a third main surface on the outside of the vehicle cabin and a fourth main surface on the inside of the vehicle cabin, and an intermediate film provided between the first glass plate and the second glass plate, and is a laminated glass further including a shielding layer formed on the second main surface, the third main surface, or the fourth main surface. The antenna element is formed on the surface on the inside of the vehicle cabin of the shielding layer in a plan view when the shielding layer is formed on the second main surface, or is formed on a portion overlapping the shielding layer in a plan view among the third main surface or the fourth main surface. When the shielding layer is formed on the third main surface, it is formed on a portion overlapping the shielding layer in a plan view of the fourth main surface, or is formed on the third main surface and covered by the shielding layer. When the shielding layer is formed on the fourth main surface, it is formed on the surface on the inside of the vehicle cabin of the shielding layer in a plan view. The vehicle antenna device according to any one of claims 1 to 7.

9. The longitudinal length of the second opening is 0.01λ or more and 0.20λ or less. The vehicle antenna device according to any one of claims 1 to 8.

10. A vehicle including a vehicle body and a vehicle antenna device. The vehicle body has a first opening provided in a first metal member of a roof portion and a second opening provided in a second metal member of a side portion and adjacent to the first opening. The vehicle antenna device includes a dielectric substrate provided in the first opening and an antenna element for a monopole antenna formed on the main surface on the inside of the vehicle cabin of the dielectric substrate, the antenna element including a first radiation element extending parallel to the inner edge of the first opening. When the wavelength of the radio wave transmitted or received by the antenna element in free space is λ, in a front view of the second opening, the lateral length of the second opening is 0.05λ or more and 0.25λ or less.

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