Vehicle antenna equipment and antenna module

Abstract

Provided is a vehicle antenna device that can ensure desired antenna characteristics for both a satellite antenna and a communication antenna.　This vehicle antenna device comprises: a dielectric plate attached to a vehicle; a conductor plate disposed in proximity to the dielectric plate; a satellite antenna that is provided below the conductor plate and that receives radio waves arriving through the dielectric plate from satellites; and a communication antenna that is provided below the satellite antenna and that transmits / receives radio waves in a horizontal direction through the dielectric plate to / from the outside of the vehicle. The satellite antenna is provided with a radiation conductor that does not overlap with the conductor plate in a vertical view, and a ground conductor positioned between the radiation conductor and the communication antenna.

Description

Technical Field

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

Background Art

[0002] Conventionally, a case for accommodating a substrate on which a plurality of antennas for communicating with the outside of the vehicle, such as a GNSS (Global Navigation Satellite System) antenna, a V2X (Vehicle to Everything) antenna, and an LTE (Long Term Evolution) antenna, are mounted is attached to the inner surface of the front windshield of the vehicle. (For example, see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when a satellite antenna such as a GNSS antenna and a communication antenna such as a V2X antenna are mounted on a common single substrate, it is difficult to ensure isolation between the two antennas, and it may be difficult to ensure desired antenna characteristics such as the antenna gain and directivity of each antenna. For example, radio waves transmitted and received horizontally between the communication antenna and the outside of the vehicle may interfere with radio waves coming from satellites in the zenith direction, and the antenna characteristics of each of the satellite antenna and the communication antenna may deteriorate.

[0005] The present disclosure provides a vehicle antenna device and an antenna module capable of ensuring desired antenna characteristics for each of a satellite antenna and a communication antenna.

Means for Solving the Problems

[0006] In one aspect of this disclosure, A dielectric plate attached to the vehicle, A conductive plate adjacent to the dielectric plate, A satellite antenna is provided below the conductive plate to receive radio waves arriving from the satellite via the dielectric plate, It includes a communication antenna located below the aforementioned satellite antenna, which transmits and receives radio waves horizontally between the vehicle and the outside via the dielectric plate, The provided vehicle antenna device comprises a satellite antenna with a radiating conductor that does not overlap with the conductor plate when viewed from the vertical, and a grounding conductor located between the radiating conductor and the communication antenna.

[0007] In another aspect of this disclosure, An antenna module that can be installed near a conductive plate adjacent to a dielectric plate attached to a vehicle, When the antenna module is installed near the conductor plate, A satellite antenna is provided below the conductive plate to receive radio waves arriving from the satellite via the dielectric plate, It includes a communication antenna located below the aforementioned satellite antenna, which transmits and receives radio waves horizontally between the vehicle and the outside via the dielectric plate, The satellite antenna is provided as an antenna module comprising a radiating conductor that does not overlap with the conductor plate when viewed from the vertical direction, and a grounding conductor located between the radiating conductor and the communication antenna. [Effects of the Invention]

[0008] According to this disclosure, it is possible to provide a vehicle antenna device and antenna module that can ensure desired antenna characteristics for both the satellite antenna and the communication antenna. [Brief explanation of the drawing]

[0009] [Figure 1] This figure shows a side view of one example configuration of a vehicle antenna device according to one embodiment. [Figure 2]This figure shows a top view of a first arrangement example of a vehicle antenna device according to one embodiment. [Figure 3] This figure shows a top view of a second arrangement example of a vehicle antenna device according to one embodiment. [Figure 4] This figure shows a top view of a third arrangement example of a vehicle antenna device according to one embodiment. [Figure 5] This figure shows a top view of a fourth arrangement example of a vehicle antenna device according to one embodiment. [Figure 6] This figure shows an example of the measured directivity of a satellite antenna. [Figure 7] This figure shows an example of the measured directivity results of a communication antenna. [Modes for carrying out the invention]

[0010] The embodiments will be described below with reference to the drawings. For ease of understanding, the scale of each part in the drawings may differ from the actual scale. In directions such as parallel, right angles, orthogonal, horizontal, vertical, up and down, and left and right, deviations are permitted to the extent that they do not impair the function and effect of the embodiments. The shape of the corners is not limited to right angles, but may be rounded in an arc shape. The X-axis direction, Y-axis direction, and Z-axis direction represent the direction parallel to the X-axis, the direction parallel to the Y-axis, and the direction parallel to the Z-axis, respectively. The X-axis direction, Y-axis direction, and Z-axis direction are orthogonal to each other. Furthermore, "opposing" does not mean that all of them are opposing, but may also include the meaning that some are opposing, and "overlapping" does not mean that all of them overlap, but may also include the meaning that some overlap.

[0011] Examples of vehicle windows in this embodiment include a windshield mounted on the front of the vehicle, a rear window mounted on the rear of the vehicle, a side window mounted on the side of the vehicle, and a roof window mounted on the ceiling of the vehicle. Vehicle windows are not limited to these examples; for example, a roof window may be integrated with either or both of the windshield or the rear window.

[0012] FIG. 1 is a side view showing a configuration example of a vehicle antenna device according to an embodiment. The antenna device 101 shown in FIG. 1 is an example of a vehicle antenna device mounted on a vehicle. The antenna device 101 includes a dielectric plate 1 attached to the vehicle, a conductor plate 2 close to the dielectric plate 1, and an antenna module 201 installed in the vicinity of the conductor plate 2.

[0013] In FIG. 1, the X-axis direction represents the front-rear direction of the vehicle, the Y-axis direction represents the left-right direction (vehicle width direction) of the vehicle, and the Z-axis direction represents the up-down direction of the vehicle. In FIG. 1, the positive side of the X-axis direction is the rear side (inside the vehicle) of the vehicle, and the negative side of the X-axis direction represents the front side (outside the vehicle) of the vehicle. The XY plane is parallel to the horizontal plane, and the Z-axis direction corresponds to the vertical direction (direction perpendicular to the horizontal plane).

[0014] The dielectric plate 1 is a plate-like member mainly composed of a dielectric. The dielectric may be glass or resin. Specific examples of the dielectric plate 1 other than the window glass include a resin window, a resin plate, a resin door, etc. FIG. 1 illustrates the case where the dielectric plate 1 is a window glass (more specifically, a windshield).

[0015] The dielectric plate 1 may be a transparent (including translucent) member that transmits visible light, or a member provided with a light-shielding film (not shown) that partially blocks visible light. Specific examples of the light-shielding film include ceramics such as a black ceramic film. When the antenna module 201 and a housing 302 described later are arranged so as to overlap the light-shielding film at a viewpoint in the vertical direction from above the outside of the vehicle, the antenna module 201 and the housing 302 are less visible from the outside of the vehicle, and the design of the vehicle is improved.

[0016] The conductor plate 2 is a conductive plate-like member that is close to the dielectric plate 1. The form of being close to the dielectric plate 1 is not limited to a form separated from the dielectric plate 1 by a predetermined distance, and may include a form of contacting the dielectric plate 1. In the example shown in FIG. 1, the conductor plate 2 is located inside the vehicle with respect to the dielectric plate 1, but may be located outside the vehicle with respect to the dielectric plate 1. Also, in the example shown in FIG. 1, the conductor plate 2 is located so as to face the main surface of the dielectric plate 1 (in this example, the surface inside the vehicle), but may be located outside the periphery of the dielectric plate 1.

[0017] The conductor plate 2 may be a plate material exposed (inside the vehicle) or a plate material covered with a resin member. FIG. 1 illustrates a form in which the conductor plate 2 is covered with a resin housing 302. The conductor plate 2 may include a metal plate inside a housing 302 that houses an electronic device 301 for acquiring external information of the vehicle. Examples of the metal plate include a bracket for fixing the electronic device 301 to the vehicle body and a heat sink for releasing heat generated by the electronic device 301. The electronic device 301 may include an imaging device for imaging the outside of the vehicle. The imaging device acquires information outside the vehicle imaged through the dielectric plate 1. The electronic device 301 for acquiring external information of the vehicle is not limited to an imaging device, and may be other electronic devices such as an antenna device for wirelessly acquiring external information of the vehicle, a rain sensor for detecting rain, and a sensor for detecting the temperature and humidity inside the vehicle cabin. In particular, when the electronic device 301 is a device in which a plurality of electronic devices including an imaging device are integrated, heat management becomes important, so a metal heat sink is often mounted.

[0018] The conductor plate 2 is not limited to a metal plate housed in the housing 302, and may be other conductive plate-like members. For example, the conductor plate 2 may be a plate-like portion of the vehicle body frame or vehicle door, or a window frame such as a flange to which a window glass is attached.

[0019] The antenna module 201 is a module equipped with multiple antennas and is positioned near the dielectric plate 1 and the conductor plate 2. The antenna module 201 is positioned in the space inside the vehicle relative to the dielectric plate 1 and is fixed by fixing members (not shown) so as to fix its positional relationship with the dielectric plate 1. The antenna module 201 includes a satellite antenna 10 that receives radio waves arriving from a satellite via the dielectric plate 1, and a communication antenna 20 that transmits and receives radio waves horizontally between the vehicle and the outside via the dielectric plate 1.

[0020] In the antenna device 101, the conductor plate 2, the satellite antenna 10, and the communication antenna 20 are arranged in this order from the top to the bottom of the vehicle. In other words, the satellite antenna 10 is located below the conductor plate 2, and the communication antenna 20 is located below the satellite antenna 10.

[0021] The statement that the satellite antenna 10 is positioned below the conductor plate 2 means that the satellite antenna 10 is located in the space between the conductor plate 2 and the underside of the vehicle. Therefore, the configuration in which the satellite antenna 10 is positioned below the conductor plate 2 is not limited to the configuration in which the satellite antenna 10 overlaps with the conductor plate 2 from a vertical viewpoint, but may also include configurations such as Figure 1 in which the satellite antenna 10 does not overlap with the conductor plate 2 from a vertical viewpoint.

[0022] Similarly, when we say that the communication antenna 20 is positioned below the satellite antenna 10, it means that the communication antenna 20 is located in the space between the satellite antenna 10 and the underside of the vehicle. Therefore, the configuration in which the communication antenna 20 is positioned below the satellite antenna 10 is not limited to the configuration shown in Figure 1, where the communication antenna 20 overlaps with the satellite antenna 10 from a vertical viewpoint, but may also include configurations in which the communication antenna 20 does not overlap with the satellite antenna 10 from a vertical viewpoint.

[0023] In this example, the satellite antenna 10 has a radiating conductor 11 whose normal direction is upward and a grounding conductor 15 whose normal direction is also upward. The radiating conductor 11 and the grounding conductor 15 are arranged in this order from the top to the bottom of the vehicle.

[0024] The radiating conductor 11 does not overlap with the conducting plate 2 when viewed from the vertical direction. As a result, radio waves arriving from satellites in the zenith direction are less likely to be blocked by the conducting plate 2, and the radiating conductor 11 can receive these radio waves with high gain and desired directivity.

[0025] The grounding conductor 15 is located between the radiating conductor 11 and the communication antenna 20. The position of the grounding conductor 15 between the radiating conductor 11 and the communication antenna 20 means that the grounding conductor 15 exists in the space between the radiating conductor 11 and the communication antenna 20. In other words, the grounding conductor 15 is located at a position that crosses a line segment connecting any point on the radiating conductor 11 and any point on the radiating plate 21 of the communication antenna 20.

[0026] The grounding conductor 15 is positioned between the radiating conductor 11 and the communication antenna 20, so that the grounding conductor 15 functions as a means of providing isolation between the satellite antenna 10 and the communication antenna 20. Therefore, interference between the radio waves transmitted and received horizontally by the communication antenna 20 to and from the outside of the vehicle and the radio waves arriving from the satellite in the zenith direction is suppressed, thereby ensuring the respective antenna characteristics of the satellite antenna 10 and the communication antenna 20.

[0027] The satellite antenna 10 is, for example, a patch antenna in which a dielectric layer is interposed between the radiating conductor and the ground conductor. In the example shown in Figure 1, the satellite antenna 10 is a patch antenna having a radiating conductor 11, a dielectric layer 12, a radiating conductor 13, an insulating layer 14, and a ground conductor 15. The configuration of the satellite antenna 10 may be different from that of a patch antenna.

[0028] Radiating conductor 11 is a first radiating element that receives radio waves in the first frequency band arriving from the satellite, and radiating conductor 13 is a second radiating element that receives radio waves in the second frequency band arriving from the satellite. The second frequency band is a different frequency band from the first frequency band. For example, if the satellite antenna 10 is a GNSS antenna, the first frequency band is the 1.2 GHz band including the frequency of the L5 wave, and the second frequency band is the 1.6 GHz band including the frequency of the L1 wave.

[0029] Radiating conductors 11 and 13 are radiating elements of different sizes; in this example, radiating conductor 13 is larger than radiating conductor 11. Radiating conductors 11 and 13 can be, for example, planar rectangular conductor patterns that receive circular polarization, but the shape of radiating conductors 11 and 13 is not limited to this. For example, if the rectangular conductors of radiating conductors 11 and 13 have diagonal notches at the two corners that form the diagonals, the feed point connected to radiating conductors 11 and 13 can be limited to just one. The notches correspond to known degenerate separation elements or perturbation elements, and the area of ​​the notches removed from the rectangular conductor can be set as an area determined by the degenerate separation method. Furthermore, the satellite antenna 10 may have a configuration that has only one of radiating conductors 11 and 13. For example, if the satellite antenna 10 is a GNSS antenna, it may be an antenna that can receive only the first frequency band (1.2 GHz band), or an antenna that can receive only the second frequency band (1.6 GHz band). In this case, the satellite antenna 10 may have only one of the dielectric layers 12 and 14, and may have a structure in which one radiating conductor, one dielectric layer, and a grounding conductor 15 are stacked from top to bottom.

[0030] The dielectric layer 12 is a dielectric interposed between the radiating conductor 11 and the radiating conductor 13. The dielectric layer 12 is, for example, a dielectric substrate having a surface on which the radiating conductor 11 is formed and a back surface on which the radiating conductor 13 is formed. The radiating conductor 11 is formed in the approximate center of the surface of the dielectric layer 12, and the radiating conductor 13 is formed over almost the entire back surface of the dielectric layer 12. A specific example of the dielectric layer 12 is a ceramic substrate.

[0031] The insulating layer 14 is an insulator interposed between the radiating conductor 13 and the grounding conductor 15. The insulating layer 14 is, for example, a base made of resin or the like.

[0032] The grounding conductor 15 is a ground plate with a larger area than the insulating layer 14. The grounding conductor 15 has a larger area than the radiating conductor 13.

[0033] The radiating conductors 11 and 13 are electrically connected to one end of the signal line of a power supply cable such as a coaxial cable, and the grounding conductor 15 is electrically connected to the grounding wire of the power supply cable. The other end of the signal line is connected to a receiving device that processes the signal output from the satellite antenna 10.

[0034] The satellite antenna 10 is, for example, a GNSS antenna. GNSS (Global Navigation Satellite System) is a general term for satellite positioning systems such as the US GPS, Japan's Quasi-Zenith Satellite System (QZSS), Russia's GLONASS, Europe's Galileo, China's BeiDou, and India's NAVIC. The satellite antenna 10 is not limited to a GNSS antenna; it may also be an antenna used for satellite digital voice radio services (SDARS) or low-Earth orbit satellite communications.

[0035] The communication antenna 20 is, for example, a patch antenna in which a dielectric layer is interposed between a radiating conductor and a grounding conductor. In the example shown in Figure 1, the communication antenna 20 is a patch antenna having a radiating plate 21, a dielectric layer 22, and a grounding plate 23. The form of the communication antenna 20 may be different from that of a patch antenna; for example, it may be a slot antenna.

[0036] The radiating plate 21 is a radiating element that transmits and receives radio waves in the third frequency band to and from external communication equipment. The third frequency band transmitted and received by the radiating plate 21 of the communication antenna 20 may or may not overlap with the first frequency band received by the radiating conductor 11 of the satellite antenna 10, or the second frequency band received by the radiating conductor 13 of the satellite antenna 10. The radiating plate 21 is, for example, a planar rectangular conductor pattern that transmits and receives vertically polarized or horizontally polarized waves, but the shape of the radiating plate 21 is not limited to this.

[0037] The dielectric layer 22 is a dielectric interposed between the radiating plate 21 and the grounding plate 23. The dielectric layer 22 is, for example, a dielectric substrate having a surface on which the radiating plate 21 is formed and a back surface on which the grounding plate 23 is formed. The radiating plate 21 is formed in the approximate center of the surface of the dielectric layer 22, and the grounding plate 23 is formed over almost the entire back surface of the dielectric layer 22. A specific example of the dielectric layer 12 is a ceramic substrate.

[0038] The grounding plate 23 is a conductive plate having the same area as or a larger area than the radiating plate 21.

[0039] The radiating plate 21 is electrically connected to one end of the signal line of a power supply cable such as a coaxial cable, and the grounding plate 23 is electrically connected to the grounding wire of the power supply cable. The other end of the signal line is connected to a communication device that processes the signals input and output to and from the communication antenna 20. The communication antenna 20 may also include one or more (not shown) unpowered conductor plates spaced apart from the radiating plate 21 and the grounding plate 23. For example, two unpowered conductor plates may be provided on the surface of the dielectric layer 22, the same as the radiating plate 21, one each in the vehicle width direction (+Y axis direction and -Y axis direction) spaced apart from the radiating plate 21. When the communication antenna 20 is equipped with unpowered conductor plates, the antenna gain in the vehicle width direction in the horizontal plane is improved, and it becomes easier to obtain a wide range of directivity.

[0040] The third frequency band transmitted and received by the communication antenna 20 is a high-frequency band such as microwaves or millimeter waves (e.g., 0.3 GHz to 300 GHz). Specific examples of frequency bands included in the third frequency band are sub6 (e.g., 3.6 GHz to 6 GHz), 2.4 GHz band, 5.2 GHz band, 5.3 GHz band, 5.6 GHz band, 5.8 GHz band, and 5.9 GHz band.

[0041] The communication antenna 20 is preferably a V2X (Vehicle to Everything) antenna used for applications such as vehicle-to-vehicle communication and vehicle-to-infrastructure communication. V2X antennas can transmit and receive narrowband radio waves, such as in the 5.8GHz or 5.9GHz band, and are used in various applications such as the ETC (Electronic Toll Collection) system in Europe. The communication antenna 20 is not limited to a V2X antenna, but may also be an antenna used in other applications such as fifth-generation mobile communication systems, sixth-generation mobile communication systems, and in-vehicle radar systems.

[0042] As illustrated in Figure 1, the communication antenna 20 may be positioned on the conductor plate 2 side with respect to a virtual plane 4 that passes through the centroid 11a of the radiating conductor 11 of the satellite antenna 10 and is perpendicular to the radiating conductor 11. The virtual plane 4 faces the dielectric plate 1. By positioning the communication antenna 20 on the conductor plate 2 side with respect to the virtual plane 4, the positional relationship between the communication antenna 20, the conductor plate 2, and the radiating conductor 11 of the satellite antenna 10 becomes closer compared to a configuration where the communication antenna 20 is positioned on the opposite side of the virtual plane 4 from the conductor plate 2. This closer positional relationship allows for miniaturization of the antenna device 101. In this example, the virtual plane 4 corresponds to the YZ plane.

[0043] The end 15a of the ground conductor 15 of the satellite antenna 10 on the conductor plate 2 side and the end 23a of the conductor of the communication antenna 20 on the conductor plate 2 side may lie on a single vertical plane 5 corresponding to the YZ plane. This brings the communication antenna 20 and the satellite antenna 10 closer to the conductor plate 2, allowing the antenna device 101 to be made smaller. The end 23a is, for example, the upper end of the ground plate 23 or a part at the same potential as the ground plate 23. A part at the same potential as the ground plate 23 is, for example, the ground terminal of a connector to which one end of a coaxial cable is connected. The end 23a of the conductor of the communication antenna 20 on the conductor plate 2 side may also be in the +X axis direction (inside the vehicle) rather than the arrangement shown in Figure 1, and the vertical plane 5 may be arranged to pass through the end 15a of the ground conductor 15 of the satellite antenna 10 on the conductor plate 2 side and the upper end 21a of the radiating plate 21. In this case as well, the antenna device 101 can be made smaller.

[0044] The communication antenna 20 is, for example, a patch antenna having a radiating plate 21 whose normal direction extends at an angle of ±5° or less with respect to the horizontal plane, and a grounding plate 23 facing the conductor plate 2 side of the radiating plate 21. This reduces the angle at which radio waves transmitted horizontally from the communication antenna 20 are reflected by the grounding conductor 15 of the satellite antenna 10, compared to a configuration in which the normal direction of the radiating plate 21 extends (tilts) at an angle greater than ±5° with respect to the horizontal plane. As a result, the radio waves around the normal of the radiating plate 21 become stronger, and the communication antenna 20 can transmit and receive radio waves horizontally with high gain between the vehicle and the outside via the dielectric plate 1. If the communication antenna 20 is a V2X antenna, the normal direction (elevation or depression angle) of the radiating plate 21 may be adjusted as appropriate within the range of ±5°, according to the communication standard.

[0045] The angle θ between the straight line 6 connecting the upper end 21a of the radiating plate 21 and the end 15b of the grounding conductor 15 opposite to the conductor plate 2, and the reference plane 7 that passes through the upper end 21a of the radiating plate 21 and is perpendicular to the radiating plate 21, may be 10° or more. When the angle θ is 10° or more, the radio waves around the normal of the radiating plate 21 become stronger, and the communication antenna 20 can transmit and receive radio waves horizontally with high gain between the vehicle and the outside via the dielectric plate 1. In terms of enabling the communication antenna 20 to transmit and receive radio waves horizontally with high gain, the angle θ is preferably 12° or more, more preferably 15° or more, and even more preferably 20° or more.

[0046] The dielectric plate 1 may be inclined with respect to the horizontal plane, or it may be parallel to the horizontal plane. An example of a dielectric plate 1 inclined with respect to the horizontal plane is a window pane (more specifically, a windshield) inclined with respect to the horizontal plane at an angle α greater than 0° and less than or equal to 50°. The angle α between the dielectric plate 1 and the horizontal plane may be 40° or less, or 30° or less. Also, the angle α may be 10° or more, 15° or more, or 20° or more. An example of a dielectric plate 1 parallel to the horizontal plane (a dielectric plate 1 where the angle α is approximately equal to 0) is a roof pane.

[0047] The satellite antenna 10 and the communication antenna 20 may be housed in a single housing 3, or they may be housed in separate housings. By housing them in a single housing 3, the antenna module 201 can be made smaller.

[0048] Figures 2 to 5 show a top view of an example arrangement of a vehicle antenna device (antenna devices 101A to 101D) according to one embodiment. Figures 2 to 5 show variations in the overlapping relationship between the satellite antenna 10, the communication antenna 20, and the conductor plate 2 from a vertical viewpoint.

[0049] As shown in Figures 2 to 4, if the conductor plate 2 does not overlap with the radiating conductor 13 and the ground conductor 15 from a vertical viewpoint, the radio waves arriving from the satellite to the radiating conductors 11 and 13 will not be easily blocked by the conductor plate 2. As a result, the satellite antenna 10 can receive these radio waves with high antenna gain and desired directivity, ensuring the antenna characteristics of the satellite antenna 10. Note that, as shown in Figure 5, the conductor plate 2 does not overlap with the radiating conductor 13 from a vertical viewpoint, but may overlap with the ground conductor 15. In this configuration as well, the reduction in the antenna gain of the satellite antenna 10 can be suppressed, and the antenna characteristics of the satellite antenna 10 can be ensured.

[0050] As shown in Figures 2 to 5, the communication antenna 20 may include a conductor 24 that overlaps with at least one of the radiating conductors 11, 13, and grounding conductor 15 when viewed from a vertical direction. More preferably, the conductor 24 may overlap with the radiating conductors 11, 13, and 15 when viewed from a vertical direction. This brings the satellite antenna 10 and the communication antenna 20 closer to each other compared to a configuration in which the conductor 24 does not overlap with any of the radiating conductors 11, 13, and 15, thus allowing for miniaturization of the antenna devices 101A to 101D. The conductor 24 of the communication antenna 20 may be the radiating plate 21 or grounding plate 23 as described above, or an unpowered conductor plate (not shown), or a part at the same potential as the grounding plate 23.

[0051] As shown in Figures 2 to 5, the conductor plate 2, satellite antenna 10, and communication antenna 20 may overlap a vertical plane 8 that is substantially perpendicular to the dielectric plate 1. The vertical plane 8 is a virtual plane perpendicular to the horizontal plane, and in this example, it corresponds to the XZ plane. By having the conductor plate 2, satellite antenna 10, and communication antenna 20 overlap a vertical plane 8, the external dimensions in the Y-axis direction can be reduced, and the antenna device and antenna module can be miniaturized. The vertical plane 8 is, for example, a plane that passes through the center of the vehicle's width.

[0052] Note that the conductor plate 2, satellite antenna 10, and communication antenna 20 do not necessarily have to overlap on a single vertical plane 8. For example, two of the conductor plate 2, satellite antenna 10, and communication antenna 20 may overlap on a single vertical plane 8, while one does not. For example, the satellite antenna 10 may be positioned on the positive side of the Y-axis direction relative to the vertical plane 8 so as not to overlap with the vertical plane 8, and the communication antenna 20 may be positioned on the negative side of the Y-axis direction relative to the vertical plane 8 so as not to overlap with the vertical plane 8.

[0053] Figure 6 shows an example of the measured directivity results of a satellite antenna 10 receiving a 1575.42 MHz L1 wave (right-hand circular polarization) in the configuration shown in Figure 1, where the dielectric plate 1 is a windshield. The overlap amount L shown in Figure 6 represents the distance in the X-axis direction between the end 2a of the conductor plate 2 and the end 15a of the ground conductor 15 in Figure 1. When L is a positive value, it indicates that the end 15a is located on the positive side of the X-axis direction with respect to the YZ plane passing through the end 2a. When L is a value of zero, it indicates that the end 15a is located on the YZ plane passing through the end 2a. When L is a negative value, it indicates that the end 15a is located on the negative side of the X-axis direction with respect to the YZ plane passing through the end 2a.

[0054] The average gain of the upper hemisphere of the satellite antenna 10 was measured at +3.2 dBi when L = -10 mm and at +3.0 dBi when L = 0 mm. In other words, when the satellite antenna 10 is shifted 10 mm on the negative side (vehicle front side) in the X-axis direction relative to the conductor plate 2 (L = -10 mm), the effect of radio wave shielding by the conductor plate 2 is reduced compared to when it is not shifted (L = 0 mm), thus improving the antenna characteristics of the satellite antenna 10.

[0055] Figure 7 shows an example of measured directivity results for a communication antenna 20 receiving 5850 MHz vertical polarization in the configuration shown in Figure 1, where the dielectric plate 1 is a windshield. Figure 7 shows the directivity in a plane inclined at 10° with respect to the horizontal plane (XY plane) passing through the centroid of the radiating plate 21, i.e., a plane with an elevation angle of +10°. Also, during the measurement in Figure 7, the radiating plate 21 is positioned along the YZ plane parallel to the vertical direction, and the vertical plane 5 shown in Figure 1 is defined as the vertical plane passing through the end 2a of the conductor plate 2. In Figure 1, the intersection point of the reference plane 7 and the dielectric plate 1 is defined as intersection point 1a.

[0056] Furthermore, in the configuration shown in Figure 1, the communication antenna 20 has two unpowered conductor plates (not shown) on the dielectric layer 22, on the same main surface as the radiating plate 21, spaced apart from the radiating plate 21 in the +Y axis direction and the -Y axis direction, respectively. The unpowered conductor plates are rectangular conductor plates with the longer side in the Z axis direction and the shorter side in the Y axis direction, as viewed from the X axis direction of the communication antenna 20.

[0057] Figure 7(a) shows the configuration shown in Figure 1, but without the satellite antenna 10 and with the communication antenna 20 located towards the rear of the vehicle. The measurement conditions in Figure 7(a) are: Horizontal distance from radiation plate 21 to intersection 1a: 176 mm Horizontal distance from vertical plane 5 to contact plate 23: -2 mm (contact plate 23 is on the front side of the vehicle relative to vertical plane 5) That's what I decided.

[0058] Figure 7(b) shows the configuration shown in Figure 1, but with a satellite antenna 10 and a communication antenna 20 located towards the rear of the vehicle. The measurement conditions in Figure 7(b) are: Horizontal distance from radiation plate 21 to intersection 1a: 176 mm Horizontal distance from vertical plane 5 to contact plate 23: -2 mm (contact plate 23 is on the front side of the vehicle relative to vertical plane 5) Horizontal distance from vertical plane 5 to end 15a of grounding conductor 15: 10.4 mm (end 15a is on the rear side of the vehicle relative to vertical plane 5) Horizontal distance from vertical plane 5 to the end of radiating conductor 13: -12 mm (the end of radiating conductor 13 is on the front side of the vehicle relative to vertical plane 5) The angle θ of the straight line connecting the upper end 21a of the radiation plate 21 and the end 15b of the grounding conductor 15 with respect to the horizontal plane is 20°. That's what I decided.

[0059] Figure 7(c) shows the configuration shown in Figure 1, but without the satellite antenna 10 and with the communication antenna 20 located towards the front of the vehicle. The measurement conditions in Figure 7(c) are: Horizontal distance from radiation plate 21 to intersection 1a: 126 mm Horizontal distance from vertical plane 5 to contact plate 23: -52 mm (contact plate 23 is on the front side of the vehicle relative to vertical plane 5) That's what I decided.

[0060] Figure 7(d) shows the configuration shown in Figure 1, but with a satellite antenna 10 and a communication antenna 20 located towards the front of the vehicle. The measurement conditions in Figure 7(d) are: Horizontal distance from radiation plate 21 to intersection 1a: 126 mm Horizontal distance from vertical plane 5 to contact plate 23: -52 mm (contact plate 23 is on the front side of the vehicle relative to vertical plane 5) Horizontal distance from vertical plane 5 to end 15a of grounding conductor 15: 10.4 mm (end 15a is on the rear side of the vehicle relative to vertical plane 5) Horizontal distance from vertical plane 5 to the end of radiating conductor 13: -12 mm (the end of radiating conductor 13 is on the front side of the vehicle relative to vertical plane 5) The angle θ of the straight line connecting the upper end 21a of the radiation plate 21 and the end 15b of the grounding conductor 15 with respect to the horizontal plane is 72°. That's what I decided.

[0061] The average gain around the entire circumference in a plane inclined at 10° with respect to the horizontal plane passing through the centroid of the radiator 21 was measured as +2.0 dBi in the case of Figure 7(a) and as +2.4 dBi in the case of Figure 7(b). In the case of Figure 7(b), the radio waves are reflected by the ground conductor 15 of the satellite antenna 10, strengthening the radio waves around the normal to the radiator 21. As a result, the antenna characteristics of the communication antenna 20 are improved compared to the case of Figure 7(a), where there is no ground conductor 15.

[0062] The average gain around the entire circumference in a plane inclined at 10° with respect to the horizontal plane passing through the centroid of the radiator 21 was measured as +2.2 dBi in the case of Figure 7(c) and as +2.6 dBi in the case of Figure 7(d). In the case of Figure 7(d), the radio waves are reflected by the ground conductor 15 of the satellite antenna 10, strengthening the radio waves around the normal to the radiator 21. As a result, the antenna characteristics of the communication antenna 20 are improved compared to the case of Figure 7(c), where the ground conductor 15 is absent.

[0063] Although embodiments have been described above, the technology of this disclosure is not limited to the embodiments described above. Various modifications and improvements are possible, such as combinations or substitutions with some or all of the other embodiments. Furthermore, the entire contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2022-019909, filed on February 10, 2022, are incorporated herein by reference as disclosure of the present invention. [Explanation of symbols]

[0064] 1 Dielectric plate 2 Conductor plates 2a end 3 cabinets 4. Virtual plane 5 Vertical plane 6 straight lines 7 Reference plane 8 Vertical plane 10 Satellite Antennas 11 Radiating conductors 11a Center of gravity 12 Dielectric layer 13 Radiating conductors 14. Insulating layer 15 Ground conductor 15a,15b end 20 Communication Antennas 21 Radiation plate 21a top end 22 Dielectric layer 23 Ground plate 23a End 24 Conductors 101, 101A, 101B, 101C, 101D Antenna equipment 201 Antenna Module 301 Electronic equipment 302 enclosures α,θ angle

Claims

1. A dielectric plate attached to the vehicle, A conductive plate adjacent to the dielectric plate, A satellite antenna is provided below the conductive plate to receive radio waves arriving from the satellite via the dielectric plate, It includes a communication antenna located below the aforementioned satellite antenna, which transmits and receives radio waves horizontally between the vehicle and the outside via the dielectric plate, The satellite antenna is a vehicle antenna device comprising a radiating conductor that does not overlap with the conductor plate when viewed from the vertical direction, and a grounding conductor located between the radiating conductor and the communication antenna.

2. The vehicle antenna device according to claim 1, wherein the conductor plate does not overlap with the radiating conductor and the grounding conductor when viewed from a vertical direction.

3. The vehicle antenna device according to claim 1 or 2, wherein the communication antenna includes a conductor that, in view from a vertical direction, overlaps with at least one of the radiating conductor and the grounding conductor.

4. The vehicle antenna device according to claim 3, wherein the conductor of the communication antenna overlaps with the radiating conductor and the grounding conductor when viewed from a vertical direction.

5. The vehicle antenna device according to claim 1 or 2, wherein the dielectric plate is inclined with respect to a horizontal plane.

6. The vehicle antenna device according to claim 1 or 2, wherein the communication antenna is positioned on the conductor plate side with respect to a virtual plane that passes through the centroid of the radiating conductor and is perpendicular to the radiating conductor, and is facing the dielectric plate.

7. The vehicle antenna device according to claim 6, wherein the end of the grounding conductor on the conductor plate side and the end of the conductor of the communication antenna on the conductor plate side lie on a single vertical plane.

8. The vehicle antenna device according to claim 1 or 2, wherein the conductive plate includes a metal plate in a housing that houses electronic equipment for acquiring external information of the vehicle.

9. The vehicle antenna device according to claim 8, wherein the metal plate is a heat sink that releases heat generated by the electronic device.

10. The vehicle antenna device according to claim 8, wherein the electronic device includes an imaging device for imaging the outside of the vehicle.

11. The vehicle antenna device according to claim 1 or 2, wherein the communication antenna is a patch antenna having a radiating plate whose normal direction extends at an angle of ±5° or less with respect to the horizontal plane, and a grounding plate facing the conductor plate side of the radiating plate.

12. The vehicle antenna device according to claim 11, wherein the angle θ formed by the straight line connecting the upper end of the radiating plate and the end of the grounding conductor opposite to the conductor plate, which passes through the upper end of the radiating plate and is perpendicular to the radiating plate, is 10° or more.

13. The vehicle antenna device according to claim 1 or 2, wherein the dielectric plate is a window pane.

14. The vehicle antenna device according to claim 13, wherein the window glass is inclined at an angle of 0° to 50° with respect to the horizontal plane.

15. The vehicle antenna device according to claim 1 or 2, wherein the satellite antenna is a GNSS antenna.

16. The vehicle antenna device according to claim 1 or 2, wherein the communication antenna is a V2X antenna.

17. The vehicle antenna device according to claim 1 or 2, wherein the satellite antenna and the communication antenna are housed in a single housing.

18. The vehicle antenna device according to claim 1 or 2, wherein the conductor plate, the satellite antenna, and the communication antenna overlap on a vertical plane substantially perpendicular to the dielectric plate.

19. The vehicle antenna device according to claim 18, wherein the vertical plane is a plane that passes through the center of the vehicle's width.

20. An antenna module that can be installed near a conductive plate adjacent to a dielectric plate attached to a vehicle, When the antenna module is installed near the conductor plate, A satellite antenna is provided below the conductive plate to receive radio waves arriving from the satellite via the dielectric plate, It includes a communication antenna located below the aforementioned satellite antenna, which transmits and receives radio waves horizontally between the vehicle and the outside via the dielectric plate, The satellite antenna is an antenna module comprising a radiating conductor that does not overlap with the conductor plate when viewed from the vertical direction, and a grounding conductor located between the radiating conductor and the communication antenna.

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