Antenna device and vehicle

Abstract

This antenna device comprises an antenna element disposed in a recess 2 on the exterior of a moving body, and a non-feeding element of which the center is disposed at a position higher than the horizontal plane in which the center of the antenna element is positioned in the recess. In the antenna device, furthermore, the moving body is a vehicle, and the recess may be provided in a roof 1 of the vehicle.

Description

[Technical field]

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

[0002] Advances are being made in developing technology that will embed an antenna device in the roof of a vehicle, thereby eliminating the need for the antenna device to protrude from the roof and thus preserving the aesthetic appearance of the vehicle's exterior.

[0003] For example, Patent Document 1 discloses a recess (in other words, a concave antenna storage section) in the roof, which stores an antenna device and is closed by a storage lid that constitutes part of the roof. With this configuration, there is no part that protrudes outside the vehicle body, which does not mar the design of the vehicle and prevents the antenna from being broken. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2003-017916 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the antenna device disclosed in Patent Document 1 does not sufficiently consider the possibility that the performance (or characteristics) may be degraded when the antenna device is embedded in the roof of a vehicle, for example.

[0006] The present disclosure provides, for example, a technique capable of suppressing degradation in the performance or characteristics of an antenna device embedded in the exterior of a moving object. [Means for solving the problem]

[0007] The antenna device of the present disclosure comprises an antenna element arranged in a recess in the exterior of a moving body, and a parasitic element having a center arranged in the recess at a position higher than a horizontal plane in which the center of the antenna element is located.

[0008] In addition, these comprehensive or specific aspects may be realized by a system, a method, an integrated circuit, a computer program, or a recording medium, or may be realized by any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium. Effect of the Invention

[0009] According to one aspect of the present disclosure, when an antenna device is embedded in the exterior of a moving object, degradation in the performance or characteristics of the antenna device can be suppressed.

[0010] Further advantages and benefits of an embodiment of the present disclosure will become apparent from the specification and drawings, in which such advantages and / or benefits are provided by some of the embodiments and features described in the specification and drawings, respectively, but not necessarily all of which are provided to obtain one or more identical features. [Brief description of the drawings]

[0011] [Figure 1] 1A and 1B are a perspective view and a cross-sectional view showing an example of a configuration of a vehicle roof embedded antenna device according to an embodiment of the present disclosure; [Diagram 2] 1A and 1B are a perspective view and a cross-sectional view showing a configuration of a vehicle roof embedded antenna device that is used as a comparison target for a vehicle roof embedded antenna device according to an embodiment of the present disclosure; [Diagram 3] 1A and 1B are a perspective view and a cross-sectional view showing a configuration of a vehicle roof-protruding antenna device that is used as a comparison target for a vehicle roof embedded antenna device according to an embodiment of the present disclosure; [Figure 4] FIG. 1 is a diagram showing an example of a radiation pattern of a vehicle roof embedded antenna device according to an embodiment of the present disclosure. [Diagram 5]FIG. 1 is a side view showing an example of a vehicle equipped with a vehicle roof embedded antenna device according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, the embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed explanation than necessary may be omitted. For example, detailed explanation of already well-known matters or duplicate explanation of substantially the same configuration may be omitted. This is to avoid the following explanation becoming unnecessarily redundant and to facilitate understanding by those skilled in the art.

[0013] It should be noted that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0014] (One embodiment) Hereinafter, one embodiment of the present disclosure will be described with reference to FIGS.

[0015] [1. Configuration] FIG. 1 is a diagram showing an example of the configuration of a vehicle roof embedded antenna device according to an embodiment of the present disclosure, in which FIG. 1(a) is a perspective view and FIG. 1(b) is an XZ cross-sectional view. In FIGS. 1 to 5, the X direction is the longitudinal length direction of the vehicle (+X is the front, -X is the rear), the Y direction is the lateral width direction of the vehicle, and the Z direction is the vertical height direction of the vehicle. In this specification, a vehicle is an example of a moving body (or mobility), and may include an automobile, a train, or a small electric vehicle. Non-limiting examples of small electric vehicles include an electric stand-up two-wheeler, an electric cart, an electric dolly, or an electric baby cart.

[0016] 1, a vehicle roof embedded antenna device 100 is used by being embedded in a recess 2 of a vehicle roof 1. The vehicle roof 1 may be painted with a conductive metal, or may be made of metal. Although the recess 2 of the vehicle roof 1 is shown as being made of a plurality of flat surfaces, it may be a curved surface or a combination of flat and curved surfaces, and does not have to be made of a conductive metal.

[0017] A patch antenna element 102-k (k=1, 2, 3, or 4) is disposed on the front surface of the dielectric substrate 101-k (k=1, 2, 3, or 4), and a GND (not shown) is formed on the back surface. The patch antenna element 102-k (k=1, 2, 3, or 4) is a square conductor with one side being, for example, half the effective wavelength taking into account wavelength shortening due to the dielectric constant of the dielectric substrate 101-k (k=1, 2, 3, or 4). The GND is a square conductor with one side being longer than half the free space wavelength.

[0018] A patch antenna is a type of planar antenna and is also called a microstrip antenna.

[0019] For example, when the radio wave used is 28 GHz, one side of the patch antenna element 102-k (k=1, 2, 3, or 4) is about 2.5 mm, and one side of the GND is about 6 mm or more, and about 10 mm is sufficient.

[0020] The dielectric substrates 101-k (k=1, 2, 3, or 4) are arranged, for example, on the inclined portion of the recess 2 of the vehicle roof 1 so as to surround (in other words, radially) the center of the bottom of the recess 2 of the vehicle roof 1. The inclined portion of the recess 2 of the vehicle roof 1 has, for example, a tilt angle α in the elevation direction with respect to the horizontal plane (XY plane) on which the bottom of the recess 2 of the vehicle roof 1 is located. As a non-limiting example, the tilt angle α is α=30 degrees. The patch antennas in each of the dielectric substrates 101-k (k=1, 2, 3, or 4) may correspond to sector antennas. In other words, a four-sector antenna may be configured by four patch antennas. The distance between the patch antenna elements 102 constituting the sector antennas facing each other on the inclined portion of the recess 2 of the vehicle roof 1 is, for example, about 18 mm. This is determined by the positional relationship including the parasitic elements described below in order to obtain the desired directivity.

[0021] Feed point 103-k (k=1, 2, 3, or 4) is provided at a position where matching with the radio circuit is obtained.

[0022] The parasitic element 104 is a conductor arranged approximately at the central axis of the four-sector antenna, for example, approximately equidistant from each of the two opposing sector antennas. The center of the parasitic element 104 is arranged at a position higher than the horizontal plane 21 where the center of the patch antenna element 102-k (k=1, 2, 3, or 4) is located. The parasitic element 104 is not in contact with the bottom surface of the recess 2 of the vehicle roof 1, but is arranged at a predetermined distance, and its length is set to be shorter than half the wavelength. The parasitic element 104 may be integrated with a resin cover (not shown) that covers the recess 2 of the vehicle roof 1, or may be fixed somewhere in the recess 2 of the vehicle roof 1, for example, to the bottom at a predetermined distance from the bottom.

[0023] [2. Operation] An example of the operation of the vehicle roof embedded antenna device 100 configured as above will be described below in comparison with the operation of a comparative antenna device shown in Figs.

[0024] 2A and 2B are diagrams showing a configuration of a vehicle roof embedded antenna device 200 to be compared with the vehicle roof embedded antenna device 100 according to an embodiment of the present disclosure. Fig. 2A is a perspective view of the vehicle roof embedded antenna device 200, and Fig. 2B is a cross-sectional view thereof.

[0025] The difference between the vehicle roof embedded antenna device 100 shown in Fig. 1 and the vehicle roof embedded antenna device 200 shown in Fig. 2 is the presence or absence of a parasitic element 104. For example, the vehicle roof embedded antenna device 100 in Fig. 1 is provided with a parasitic element 104, whereas the vehicle roof embedded antenna device 200 in Fig. 2 is not provided with a parasitic element.

[0026] Fig. 2 shows a four-sector antenna consisting of four sectors, just like Fig. 1, but since each sector has the same configuration, Fig. 2 will be described focusing on the front sector. Patch antenna element 202-1 is arranged on the front surface of dielectric substrate 201-1, and GND (not shown) is formed on the back surface, where feeding point 203-1 is also provided. Dielectric substrate 201-1 is radially arranged along recess 2 of vehicle roof 1 in the elevation direction with respect to the horizontal plane (XY plane) at a tilt angle α = 30 degrees, for example, to form a four-sector antenna.

[0027] FIG. 3 is a diagram showing the configuration of a vehicle roof protruding antenna device 300 as another comparison target with the vehicle roof embedded antenna device 100 according to an embodiment of the present disclosure. FIG. 3(a) is a perspective view of the vehicle roof protruding antenna device 300, and FIG. 3(b) is a cross-sectional view thereof. The vehicle roof protruding antenna device 300 configures a four-sector antenna along a protruding portion 3 of a vehicle roof 1. The vehicle roof embedded antenna device 100 shown in FIG. 1 is an example in which the antenna device 100 is below the surface of the vehicle roof 1 (in other words, does not protrude from the roof surface). In contrast, the vehicle roof protruding antenna device 300 shown in FIG. 3 is formed in such a way that the antenna device 300 protrudes above the surface of the vehicle roof 1. Therefore, in the vehicle roof protruding antenna device 300 shown in FIG. 3, the antenna device 300 protrudes from the vehicle roof 1, which impairs the aesthetic appearance of the vehicle.

[0028] Fig. 3 shows a four-sector antenna consisting of four sectors, just like Fig. 1, but since each sector may have the same configuration, Fig. 3 will be described focusing on the front sector. Patch antenna element 302-1 is arranged on the front surface of dielectric substrate 301-1, and GND (not shown) is formed on the back surface, and feeding point 303-1 is provided. Dielectric substrate 301-1 is radially arranged along protrusion 3 of vehicle roof 1 in the elevation direction with respect to the horizontal plane (XY plane) at a tilt angle α = 30 degrees, for example, to form a four-sector antenna.

[0029] Fig. 4 shows an example of the radiation pattern of each of the antenna devices 100, 200, and 300 shown in Fig. 1 to Fig. 3, where Fig. 4(a) shows the radiation pattern of each of the antenna devices in the XZ plane, and Fig. 4(b) shows the radiation pattern of each of the antenna devices in the XY plane. In Fig. 4(a) and Fig. 4(b), the actual gain (sensitivity) is shown in dBi.

[0030] A solid line 401 in Figures 4(a) and 4(b) indicates the radiation pattern of the patch antenna element 102 of the vehicle roof embedded antenna device 100 shown in Figure 1. A dashed line 402 in Figures 4(a) and 4(b) indicates the radiation pattern of the patch antenna element 202 of the vehicle roof embedded antenna device 200 shown in Figure 2. A dashed line 403 in Figures 4(a) and 4(b) indicates the radiation pattern of the patch antenna element 302 of the vehicle roof protruding antenna device 300 shown in Figure 3.

[0031] Each radiation pattern shows the characteristics when GND (not shown) is grounded to the vehicle roof 1, the recessed portion 2 or the protruding portion 3.

[0032] First, let us look at the gain in the +X direction (e.g., the forward direction of the vehicle) (Z=0) in Fig. 4(a). The antenna with the highest gain among these is the vehicle roof protruding antenna device 300 (dashed line 403) shown in Fig. 3, which protrudes from the vehicle roof 1 and is therefore relatively less affected by the vehicle roof 1. The antenna with the lowest gain among these is the vehicle roof embedded antenna device 200 (dashed line 402) shown in Fig. 2, which does not have the parasitic element 104, which is therefore embedded in the vehicle roof and has no parasitic element, and is therefore most affected by the vehicle roof 1.

[0033] The vehicle roof embedded antenna device 100 (solid line 401) shown in Fig. 1 equipped with the parasitic element 104 has a lower gain in the +X direction compared to the vehicle roof protruding antenna device 300 (dash line 403), but has a higher gain in the +X direction compared to the vehicle roof embedded antenna device 200 (dashed line 402) not equipped with the parasitic element 104. This is because the parasitic element 104 provided in the vehicle roof embedded antenna device 100 shown in Fig. 1 operates as a director element. Note that the parasitic element 104 exists at approximately the same distance as seen from all four patch antenna elements 102-k (k=1, 2, 3 or 4), and therefore operates as a director element in the same manner for these four patch antenna elements.

[0034] Next, let us look at the gain in the horizontal plane (XY plane) shown in Fig. 4(b). Here, +X is the forward direction of the vehicle, and Y is the width direction of the vehicle. The vehicle roof embedded antenna device 100 (solid line 401) having the parasitic element 104 shown in Fig. 1 has the narrowest half-power angle. This can be compensated for by increasing the number of sectors. For example, the number of sectors in the vehicle roof embedded antenna device 100 shown in Fig. 1 is 4, but this can be compensated for by increasing the number of sectors to 5, 6, 7, etc.

[0035] 5 shows the vehicle roof embedded antenna device 100 shown in FIG. 1 mounted on a vehicle 50. An embodiment in which the vehicle roof embedded antenna device 100 is attached to a vehicle roof 1 is shown. It can be seen that the vehicle roof embedded antenna device 100 does not protrude from the vehicle roof 1.

[0036] [3. Effects, etc.] As described above, in this embodiment, vehicle roof embedded antenna device 100 is embedded in recess 2 of vehicle roof 1, and is radially arranged along recess 2 of vehicle roof 1 with tilt angle α=30 degrees in the elevation direction with respect to the horizontal plane (XY plane) to form a four-sector antenna. Parasitic element 104 is arranged approximately on the central axis of the four-sector antenna.

[0037] As described with reference to Figure 5, this configuration does not impair the aesthetic appearance of the vehicle since there is no protrusion from the vehicle roof, and even if it is embedded in the vehicle roof, it is possible to suppress a decrease in gain in the horizontal plane.

[0038] (Other embodiments) As described above, the embodiments have been described as examples of the technology disclosed in this application. However, the technology in this disclosure is not limited to these, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made. In addition, it is also possible to combine the components described in the above embodiments to create new embodiments.

[0039] Therefore, other embodiments will be exemplified below.

[0040] In the embodiment, a patch antenna made of a dielectric substrate 101-k (k=1, 2, 3, or 4) has been described as an example of an antenna element. The antenna element may be any element capable of transmitting and receiving electromagnetic waves at a desired frequency. For example, the antenna element may be a linear antenna, a loop antenna, or a combination of these. Therefore, the antenna element is not limited to a patch antenna made of a dielectric substrate. A patch antenna made of a dielectric substrate has the advantage that an antenna device can be easily and inexpensively realized.

[0041] In the embodiment, a tilt angle α of 30 degrees has been described as an example. The tilt angle α may be any angle that can obtain a desired radiation directivity. Therefore, the tilt angle α is not limited to 30 degrees. The tilt angle α may be large as long as the parasitic elements do not protrude from the vehicle roof, which is also desirable from the viewpoint of suppressing a decrease in horizontal plane gain.

[0042] In the embodiment, the case where the number of sectors is four has been described. The number of sectors may be any number that allows communication to be established with a base station or access point that emits radio waves to be received. Therefore, the number of sectors may be less than or greater than four and is not limited to four. The spacing between the sectors is also not limited. In order to increase the coverage rate in the horizontal plane, it is preferable to increase the number of sectors, but if the purpose is to cover a specific direction in the horizontal plane, the number of antennas may be one without a sector configuration.

[0043] In the embodiment, the case where the number of parasitic elements 104 is one and the parasitic elements are arranged on the central axis of the sector antenna array has been described. It is preferable to arrange the parasitic elements 104 at a position higher than the horizontal plane where the antenna elements are located in order to suppress a gain decrease in the horizontal plane, but the number of parasitic elements and their horizontal arrangement positions may be any positions that suppress a gain decrease in the horizontal plane caused by the vehicle roof. Therefore, the number of parasitic elements is not limited to one, and their arrangement is not limited to the central axis of the sector antenna array. However, since a configuration in which one parasitic element is arranged on the central axis of the sector antenna array can obtain the same effect in suppressing a gain decrease in the horizontal plane for each element of the sector antenna, a configuration in which one parasitic element is arranged on the central axis of the sector antenna array can be one of effective candidates for a simple configuration.

[0044] The present disclosure can be realized in software, hardware, or software in conjunction with hardware.

[0045] Each functional block used in the description of the above embodiments may be partially or entirely realized as an LSI, which is an integrated circuit, and each process described in the above embodiments may be partially or entirely controlled by one LSI or a combination of LSIs. The LSI may be composed of individual chips, or may be composed of one chip that includes some or all of the functional blocks. The LSI may have data input and output. Depending on the degree of integration, the LSI may be called an IC, a system LSI, a super LSI, or an ultra LSI.

[0046] The method of integration is not limited to LSI, and may be realized by a dedicated circuit, a general-purpose processor, or a dedicated processor. Also, after LSI manufacturing, a programmable FPGA (Field Programmable Gate Array) or a reconfigurable processor that can reconfigure the connections and settings of circuit cells inside the LSI may be used. The present disclosure may be realized as digital processing or analog processing.

[0047] Furthermore, if a new integrated circuit technology that can replace LSI appears due to the progress of semiconductor technology or a derivative technology, it is possible to integrate the functional blocks using that technology. The application of biotechnology is also a possibility.

[0048] The present disclosure may be implemented in any type of apparatus, device, or system with communications capabilities (collectively, communications apparatus), including, but not limited to, telephones (e.g., cell phones, smartphones, etc.), tablets, personal computers (PCs) (e.g., laptops, desktops, notebooks, etc.), cameras (e.g., digital still / video cameras), digital players (e.g., digital audio / video players), wearable devices (e.g., wearable cameras, smart watches, tracking devices, etc.), game consoles, digital book readers, telehealth / telemedicine devices, communications-enabled vehicles or mobile conveyances (e.g., cars, planes, ships, etc.), and combinations of the above-mentioned devices.

[0049] Communications Equipment includes, but is not limited to portable or mobile equipment, non-portable or fixed equipment, devices and systems of any kind, such as smart home devices (appliances, lighting equipment, smart meters or metering devices, control panels, etc.), vending machines and any other "Things" that may exist on an Internet of Things (IoT) network.

[0050] Communications include data communications via cellular systems, wireless LAN systems, communications satellite systems, etc., as well as data communications via combinations of these.

[0051] A communications apparatus also includes devices, such as controllers and sensors, connected or coupled to a communications device that performs the communications functions described in this disclosure, such as controllers and sensors that generate control and data signals used by the communications device to perform the communications functions of the communications apparatus.

[0052] The communication apparatus also includes infrastructure facilities, such as base stations, access points, and any other apparatus, device, or system that communicates with or controls the various apparatuses listed above, but are not limited to these.

[0053] It should be noted that the above-described embodiments are intended to illustrate the technology of the present disclosure, and various modifications, substitutions, additions, omissions, and the like can be made within the scope of the claims or their equivalents.

[0054] <Summary of this disclosure> The antenna device of the present disclosure comprises an antenna element arranged in a recess in the exterior of a moving body, and a parasitic element having a center arranged in the recess at a position higher than a horizontal plane in which the center of the antenna element is located.

[0055] In the antenna device of the present disclosure, the moving body is a vehicle, and the recess is provided in a roof of the vehicle.

[0056] In the antenna device of the present disclosure, the antenna element is a patch antenna configured using a dielectric substrate.

[0057] In the antenna apparatus of the present disclosure, the antenna element is tilted in an elevation direction with respect to the horizontal plane.

[0058] In the antenna device of the present disclosure, a plurality of the antenna elements are arranged surrounding the center of the bottom of the recess to form a sector configuration.

[0059] In the antenna device of the present disclosure, the parasitic element is disposed on the central axis of the sector configuration.

[0060] In the antenna device of the present disclosure, the parasitic element has a rod-like shape.

[0061] In the antenna device of the present disclosure, the parasitic element is attached to the rear surface of a lid that covers the recess.

[0062] The vehicle of the present disclosure comprises a recess provided in a roof, an antenna device housed in the recess, and a lid covering the recess in which the antenna device is housed, the antenna device comprising an antenna element arranged in the recess, and a parasitic element attached to the back surface of the lid or to the recess, the center of the parasitic element being located at a position higher than the horizontal plane in which the center of the antenna element is located when the recess is covered by the lid.

[0063] The disclosures of the specification, drawings and abstract contained in Japanese Patent Application No. 2019-182438, filed on October 2, 2019, are incorporated herein by reference in their entirety. [Industrial Applicability]

[0064] The present disclosure is applicable to an antenna device that is embedded in the roof of a vehicle, for example. [Explanation of symbols]

[0065] 1 Vehicle roof 2 Recess 3 Convex 21 horizontal plane 50 vehicles 100 Vehicle roof embedded antenna device 101-1 Dielectric substrate 101-2 Dielectric substrate 101-3 Dielectric substrate 101-4 Dielectric substrate 102-1 Patch antenna element 102-2 Patch antenna element 102-3 Patch antenna element 102-4 Patch antenna element 103-1 Power supply point 103-2 Power supply point 103-3 Power supply point 103-4 Power supply point 104 Parasitic element 200 Vehicle roof embedded antenna device 201-1 Dielectric substrate 202-1 Patch antenna element 203-1 Power supply point 300 Vehicle roof protruding antenna device 301-1 Dielectric substrate 302-1 Patch antenna element 303-1 Power supply point

Claims

1. An antenna element disposed in a recess in the exterior of a moving object; a parasitic element having a center disposed at a position higher than a horizontal plane on which the center of the antenna element is located in the recess; Equipped with The antenna elements are tilted in an elevation direction relative to the horizontal plane. Antenna device.

2. An antenna element disposed in a recess in the exterior of a moving object; a parasitic element having a center disposed at a position higher than a horizontal plane on which the center of the antenna element is located in the recess; Equipped with A plurality of the antenna elements are arranged around a bottom center of the recess to form a sector configuration. Antenna device.

3. The parasitic element is arranged on a central axis of the sector configuration.

3. The antenna device according to claim 2.

4. An antenna element disposed in a recess in the exterior of a moving object; a parasitic element having a center disposed at a position higher than a horizontal plane on which the center of the antenna element is located in the recess; Equipped with The parasitic element is rod-shaped. Antenna device.

5. An antenna element disposed in a recess in the exterior of a moving object; a parasitic element having a center disposed at a position higher than a horizontal plane on which the center of the antenna element is located in the recess; Equipped with The parasitic element is attached to the back surface of a cover portion that covers the recess portion. Antenna device.

6. The moving body is a vehicle, and the recess is provided in a roof of the vehicle. An antenna device according to any one of the preceding claims.

7. The antenna element is a patch antenna constructed using a dielectric substrate. An antenna device according to any one of the preceding claims.

8. A recess provided in the roof; an antenna device accommodated in the recess; a cover portion for covering the recess portion in which the antenna device is housed, The antenna device comprises: an antenna element disposed in the recess; a parasitic element attached to the rear surface of the lid or to the recess; a center of the parasitic element is located at a position higher than a horizontal plane on which a center of the antenna element is located when the recess is covered by the lid portion; vehicle.

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