Vehicle-mounted antenna device

Abstract

The vehicle-mounted antenna device (10) comprises: an antenna base (100) having a bottom portion (102); a substrate (200) arranged above the bottom portion and opposite to the bottom portion; and an antenna vibrator (400) arranged on the periphery and constituting a slot antenna by using the side ends of the antenna base as opposite sides of a slot.

Description

Technical Field

[0001] The present invention relates to a vehicle-mounted antenna device having an antenna element operating as a slot antenna. Background Art

[0002] As a method of feeding power to a slot antenna, a method using a transmission line disposed on a substrate is known (for example, refer to Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-41994 Summary of the invention

[0006] In recent years, in the field of automobile communications, the demand for in-vehicle information services (Telematics) has increased, and an in-vehicle antenna device that meets this demand has been sought. From the viewpoint of vehicle design, it is desired to achieve a low-profile in-vehicle antenna device.

[0007] Since the vehicle-mounted antenna device uses the roof of the vehicle for installation as a ground plane, a monopole antenna is often used as an antenna element. In the vehicle-mounted antenna device for vehicle-mounted information services, a high gain in the horizontal direction is desired, but if the monopole antenna is made low-profile in order to achieve a low-profile vehicle-mounted antenna device, the gain in the horizontal direction will be degraded.

[0008] Therefore, the use of a slot antenna is considered as an antenna element mounted on a vehicle-mounted antenna device. However, the conventional method of using a slot antenna has the following problems. When a transmission line is used to supply power to the slot antenna, the substrate on which the transmission line is disposed is usually disposed opposite to the metal plate on which the slot is disposed, which prevents the vehicle-mounted antenna device from being low-profile. As the slot antenna is sought to be low-profile, the area on which the substrate can be disposed becomes narrower.

[0009] One example of the purpose of the present invention is to propose a new technology for achieving a low-profile vehicle-mounted antenna device having a slot antenna.

[0010] One embodiment of the present invention is a vehicle-mounted antenna device, which comprises: an antenna base having a bottom portion; a substrate arranged above the bottom portion and opposite to the bottom portion; and an antenna vibrator arranged on the periphery and forming a slot antenna by using the side ends of the antenna base as opposite sides of the slot.

[0011] According to this scheme, in a vehicle-mounted antenna device having an antenna vibrator constituting a slot antenna, a low profile can be achieved. A slot antenna is configured in which the side ends of the antenna base are opposite sides of the slot. Therefore, when the bottom portion is arranged in the horizontal direction, the long side direction of the slot of the slot antenna also becomes a direction along the horizontal direction, and a horizontal gain can be obtained as a slot antenna. Since the substrate is arranged above the bottom portion and opposite to the antenna base, a low profile of the vehicle-mounted antenna device can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is an example of installing an in-vehicle antenna device.

[0013] Figure 2 This is a perspective view of the appearance of the vehicle-mounted antenna device.

[0014] Figure 3 This is a perspective view of the vehicle-mounted antenna device with the outer cover removed.

[0015] Figure 4 This is an exploded perspective view of a vehicle-mounted antenna device.

[0016] Figure 5 This is a cross-sectional view of the main parts of the vehicle-mounted antenna device.

[0017] Figure 6 is a top plan view of the substrate.

[0018] Figure 7 It is a bottom-up plan view of the substrate.

[0019] Figure 8 It is a cross-sectional view of a main part of a vehicle-mounted antenna device showing another embodiment of a spring. DETAILED DESCRIPTION

[0020] Hereinafter, an example of a preferred embodiment of the present invention will be described with reference to the drawings. In addition, the present invention is not limited to the embodiment described below, and the mode to which the present invention can be applied is not limited to the following embodiment.

[0021] [structure]

[0022] Figure 1 FIG. 1 is a diagram showing an example of a state in which the vehicle-mounted antenna device 10 of the present embodiment is mounted on the vehicle 1. Figure 1As shown, the vehicle-mounted antenna device 10 is used by being mounted in the recess 5 of the roof 3 of the vehicle 1. The vehicle-mounted antenna device 10 is formed in a thin rectangular parallelepiped shape with a thin thickness (length in the vertical direction) as a whole, and a recess 5 conforming to the shape of the vehicle-mounted antenna device 10 is formed on the roof 3. In the recess 5 in which the vehicle-mounted antenna device 10 is stored, a cover 7 is embedded in the recess 5 so as to block its opening. In order not to damage the vehicle design, the cover 7 is painted the same as the roof 3. In addition, the cover 7 is formed in a state where the upper surface of the cover 7 is a flat surface that is integrated with the roof 3 when embedded in the recess 5. By providing a waterproof elastic member such as a gasket on the cover 7, a structure is formed in which the gap between the cover 7 and the recess 5 is sealed watertightly to prevent water from entering the recess 5. Instead of forming the recess 5 on the roof 3, the vehicle-mounted antenna device 10 stored in a waterproof box or the like can be installed on the upper surface of the roof 3 for use. The exterior cover 500 of the vehicle-mounted antenna device 10 described later may also function as a waterproof box.

[0023] The front-rear, left-right, and up-down directions of the vehicle-mounted antenna device 10 are set to be the same as those of the vehicle 1 when it is installed on the vehicle 1. Figure 1 In the example shown, the vehicle-mounted antenna device 10 is installed so that the short side direction of the thin rectangular parallelepiped shape is consistent with the front-rear direction of the vehicle 1. Specifically, the thickness direction is set as the up-down direction of the vehicle-mounted antenna device 10, the direction along the long side direction is set as the left-right direction, and the direction along the short side direction is set as the front-rear direction. The up-down direction can also be called the height direction.

[0024] [Appearance]

[0025] Figure 2 to Figure 5 It is a diagram for explaining the structure of the vehicle-mounted antenna device 10 . Figure 2 It is a perspective view of the appearance of the vehicle-mounted antenna device 10 . Figure 3 It is a perspective view of the appearance of the vehicle-mounted antenna device 10 with the exterior cover 500 removed. Figure 4 It is an exploded perspective view of the vehicle-mounted antenna device 10 . Figure 5 This is a cross-sectional view of a main part of the vehicle-mounted antenna device 10 along the longitudinal direction, and is a schematic view in which the outer cover 500 and the intermediate cover 300 are omitted in order to make the electrical connection structure easier to understand.

[0026] like Figure 3As shown, the vehicle-mounted antenna device 10 has an antenna element 400 with a slot 12 extending in the front-to-back direction formed on the left and right sides, i.e., the short sides, of the thin rectangular shape after the outer packaging cover 500 is removed. The antenna element 400 is used for vehicle-mounted information services, such as in LTE (Long Term Evolution) communications. The slot 12 is formed so that both ends span the adjacent long side surfaces. Since the slot 12 has a shape along the horizontal direction (the horizontal direction is along the upper surface of the roof 3 that serves as the ground contact surface when installed on the vehicle 1), it works as a slot antenna for vertically polarized waves. Figure 3 In the figure, since it is a stereoscopic view, the slit 12 formed only on one side (left side) of the short side is shown to be easy to understand, but the slit 12 is also formed on the other side (right side) of the short side. The length (long diameter) of the slit 12 is determined according to the wavelength λ of the frequency used when operating as a slot antenna. Although the vehicle-mounted antenna device 10 of this embodiment has an antenna vibrator 400 formed with a slit 12 extending in the front-to-back direction on the short side, it may also have an antenna vibrator formed with a slit extending in the left-right direction on the long side.

[0027] In the antenna element 400, a slit 14 extending upward and having an upper end extending across the upper surface is provided on the short side surface at the upper edge of the slot 12. By providing the slit 14, the types of frequency bands that can be used in the vehicle-mounted antenna device 10 can be increased. The length (long diameter) of the slit 14 and the position of the opening end of the slit 14 in the slot 12 are determined according to the wavelength λ of the frequency in the usable frequency band whose types are increased by providing the slit 14. The antenna element 400 may also be a structure without the slit 14.

[0028] like Figure 2 , Figure 3 As shown, the vehicle-mounted antenna device 10 is provided with a connector 20 for connecting a signal cable drawn from the vehicle 1 to be installed, which is exposed on the long side of the front side of the thin rectangular parallelepiped. In this embodiment, the connector 20 is a structure provided on the long side of the front side of the vehicle-mounted antenna device 10, but it can also be provided on other sides. The vehicle-mounted antenna device 10 can output analog signals to the vehicle 1, and can also output digital signals.

[0029] like Figure 4 As shown, the vehicle-mounted antenna device 10 is configured such that a substrate 200 , an intermediate cover 300 , and an antenna element 400 are housed in order from the bottom in a space defined between a metal antenna base 100 and an outer cover 500 covering the upper portion of the antenna base 100 .

[0030] The antenna base 100 has a rectangular metal bottom portion 102 and a low metal edge portion 104 that stands up along the outer periphery of the bottom portion 102, forming a shallow flat plate shape that is rectangular in a plan view and opens upward. In order to allow the connector portion 20 provided on the substrate 200 to protrude from the front, the center of the edge portion 104 on the front side is cut away.

[0031] The substrate 200 is elastically supported by an elastic support portion sandwiched between the antenna base 100 and the substrate 200, and is arranged above the bottom surface 102 and opposite to the bottom surface 102. The elastic support portion is, for example, a metal spring 220. The spring 220 is one of the structures for ensuring the ground potential when the slot 12 is operated as a slot antenna, and is provided near the slot 12. The upper end of the spring 220 is mounted on the ground pattern on the lower surface of the substrate 200. In other words, the spring 220 is electrically connected to the ground pattern. When the substrate 200 is placed on the upper surface of the claw 106 of the antenna base 100 and screwed, the spring 220 is pressed against the upper surface of the bottom surface 102 of the antenna base 100 by the lower end, and the substrate 200 is elastically supported relative to the antenna base 100. As a result, the spring 220 also plays a function of electrically connecting the ground pattern of the substrate 200 and the antenna base 100. The spring 220 can be composed of, for example, a metal coil spring or a leaf spring.

[0032] The antenna base 100 is provided with a plurality of claws 106 in an inverted L-shaped shape when viewed from the side, by cutting through the bottom surface 102 and lifting it. The claws 106 are provided with screw holes 108 penetrating in the vertical direction. The substrate 200 elastically supported by the springs 220 is located above the claws 106. The substrate 200 is mounted above the antenna base 100 by inserting the screws 110 from below into the screw holes 108 of the claws 106 and screw holes 210 formed in the substrate 200 corresponding to the screw holes 108. The screws are fastened so that a gap is formed between the lower end of the electronic components of the substrate 200 elastically supported by the springs 220 and the bottom surface 102, so that the electronic components mounted on the lower surface of the substrate 200 do not contact the bottom surface 102. In order to stably fix the substrate 200 to the antenna base 100, it is desirable that the claws 106 are provided, for example, near the four corners of the bottom surface 102 or near the peripheral edge.

[0033] After the substrate 200 is disposed on the antenna base 100 , the intermediate cover 300 is disposed to cover the upper portion of the substrate 200 , and the antenna element 400 is disposed on the outer periphery of the intermediate cover 300 .

[0034] The intermediate cover 300 is formed of a synthetic resin having insulating properties. The intermediate cover 300 is formed in a rectangular cover shape as a whole with an opening in the center when viewed from above. The lower peripheral portion of the intermediate cover 300 is protruded downward so as to ensure a predetermined gap above the substrate 200 without interfering with the electronic components mounted on the upper surface of the substrate 200. The outer peripheral surface of the lower peripheral portion is arranged to abut against the inner peripheral surface of the edge 104 of the antenna base 100. If the lower peripheral portion is located inside the edge 104, it is not necessary to abut. Insertion holes 302 for inserting the feeding element 430 provided below the first antenna element 410 and the second antenna element 420 in the vertical direction are formed on the left and right sides of the peripheral portion of the intermediate cover 300. In addition, in order to make the connector part 20 provided on the substrate 200 protrude from the front, the lower peripheral portion of the front side is cut out near the center.

[0035] The antenna element 400 is a metal component formed by, for example, sheet metal processing of a metal plate, and is arranged on the outer periphery of the intermediate cover 300. When the antenna element 400 is arranged on the intermediate cover 300, a gap 12 is formed between the antenna element 400 and the edge 104 of the antenna base 100 opposite to it. The antenna element 400 has a first antenna element 410 and a second antenna element 420, wherein when viewed from above in a plane (when viewed from above), the first antenna element 410 is arranged at the left end portion of the first direction side, and the second antenna element 420 is arranged at the right end portion of the second direction side which is the opposite side to the first direction side. Here, the opposite side refers to a direction 180 degrees opposite to a certain direction, that is, a side (one side) in the opposite direction. For example, the opposite side of the left side surface is the right side surface.

[0036] The first antenna element 410 includes a part 412 disposed on the front side of the left end of the intermediate cover 300, and a part 414 disposed on the rear side. The parts 412 and 414 each include an upper surface portion that is L-shaped when viewed from above and is used to be placed on the intermediate cover 300, and a side surface portion that extends downward from the outer edge of the upper surface portion. The side surface portions are provided with protruding pieces 412a and 414a that protrude further downward on the front side or the rear side of the intermediate cover 300 when disposed on the outer periphery of the intermediate cover 300. The protruding pieces 412a and 414a are used to define the length (long diameter) of the slit 12. The parts 412 and 414 are formed so that, when disposed on the outer periphery of the intermediate cover 300, the gap between the ends at the left end of the intermediate cover 300 constitutes the slit 14. In this embodiment, in order to form the slit 14 forwardly relative to the open end of the slot 12 on the left side of the vehicle-mounted antenna device 10 , the length of the part 414 in the front-rear direction is formed longer than that of the part 412 .

[0037] When the first antenna element 410 is arranged at the left end of the outer peripheral portion of the intermediate cover 300, the lower portions of the protruding pieces 412a and 414a of the parts 412 and 414 abut against the upper portion of the edge 104 of the antenna base 100, thereby forming the gap 12. The gap 12 is formed between the lower sides of the side portions of the parts 412 and 414 and the upper sides of the edge 104 of the antenna base 100 facing each other, and straddling the left side surface and the adjacent front and rear side surfaces of the vehicle-mounted antenna device 10. The gap between the parts 412 and 414 forms the slit 14.

[0038] The second antenna element 420 is also configured in the same manner as the first antenna element 410. The slit 14 of the second antenna element 420 is formed at a rearward position. The second antenna element 420 is a structure in which the first antenna element 410 is arranged point-symmetrically in a plan view. That is, the second antenna element 420 includes a part 422 arranged at the rear side of the right end of the intermediate cover 300, and a part 424 arranged at the front side. The parts 422 and 424 are respectively provided with protruding pieces 422a and 424a for defining the length (long diameter) of the slit 12.

[0039] The antenna element 400 is provided with a feeding element 430 as a feeding structure for operating the slot 12 as a slot antenna. Regarding the first antenna element 410, the feeding element 430 is provided on the part 414 arranged on the rear side, and regarding the second antenna element, the feeding element 430 is provided on the part 424 arranged on the front side. Figure 5 As shown in FIG. 1 , the feeding element 430 is formed in an L shape when viewed from the side. One end of the feeding element 430 is connected to the lower edge of the antenna element 400 in a manner that the cross section of the one end is parallel to a plane formed by the up-down direction and the front-back direction. The other end of the feeding element 430 is connected to the feeding line 206 arranged on the substrate 200 in a manner that the cross section of the other end is parallel to a plane formed by the front-back direction and the left-right direction. The connection position of the feeding element 430 in the antenna element 400 becomes the feeding position for the slot antenna, and is positioned according to the wavelength λ of the frequency to be used.

[0040] The outer cover 500 is formed of a synthetic resin having radio wave permeability. The outer cover 500 is a cover for covering the entire upper portion of the vehicle-mounted antenna device 10. In order to allow the connector portion 20 provided on the substrate 200 to protrude from the front, the central portion of the front side of the outer cover 500 is cut away. The inner dimensions of the outer cover 500 are formed to be slightly larger than the outer dimensions of the antenna base 100. After the substrate 200, the intermediate cover 300, and the antenna vibrator 400 are arranged in order above the antenna base 100, the outer cover 500 is installed in a manner that covers them as a whole from above.

[0041] The substrate 200 is a double-sided substrate on which electronic components are mounted on the upper surface and the lower surface. Figure 6 This is a diagram for explaining the wiring structure on the upper surface of the substrate 200 , and is a plan view schematically showing a part of the substrate 200 as viewed from above. Figure 7 This is a diagram for explaining the wiring structure on the lower surface of the substrate 200 , and is a plan view schematically showing a part of the substrate 200 as viewed from below. Figure 6 , Figure 7 Although the right end portion of the substrate 200 is shown, the left end portion has the same structure.

[0042] like Figure 6 As shown, the upper surface of the substrate 200 has an electronic circuit arrangement portion 202 in the central portion when viewed in a plan view, and a ground pattern 204 and a feeder line 206 for the slot antenna are provided so as to surround the outer side of the electronic circuit arrangement portion 202. The electronic circuit arrangement portion 202 includes a feeder circuit, other antenna elements such as a patch antenna, and various electronic circuits for antennas such as a signal processing circuit.

[0043] exist Figure 6 , the arrangement of the feeding element 430 is shown by a dotted line. In the upper surface of the substrate 200, the feeding line 206 extends from the electronic circuit arrangement portion 202 to the vicinity of the edge of the substrate 200 where the lower end of the feeding element 430 contacts. The connection between the feeding line 206 and the feeding element 430 can be, for example, a structure as follows: an insertion port for inserting the lower end of the feeding element 430 into the feeding line 206 is provided on the substrate 200, and the lower end of the feeding element 430 is inserted into the insertion port for connection. The connection between the feeding line 206 and the feeding element 430 can also be performed by soldering. Any structure is acceptable as long as the two can be electrically connected.

[0044] An antenna matching circuit 208 is provided in the middle of the feed line 206. The antenna matching circuit 208 is arranged close to the connection portion between the feed line 206 and the feed element 430. The antenna matching circuit 208 is a circuit for performing impedance matching between the antenna element 400 and the subsequent circuit connected via the feed line 206. The antenna matching circuit 208 can increase the number of frequency bands that can be used in the vehicle-mounted antenna device 10.

[0045] The ground pattern 204 is an area other than the electronic circuit arrangement portion 202, and is formed in an area other than the arrangement area of ​​the feed line 206 and the antenna matching circuit 208, and other areas other than the non-ground area. The non-ground area is an area within a predetermined distance from the edge where the antenna element 400 is located, and is an area provided to separate the antenna element 400 and the ground pattern 204 by a predetermined distance or more. The predetermined distance is determined based on the wavelength λ of the frequency in the frequency band that can be used in the vehicle-mounted antenna device 10. The ground pattern 204 is formed as a so-called integral pattern in which the entire area is a planar ground electrode in order to counteract noise.

[0046] like Figure 7 As shown in FIG. 1 , the lower surface of the substrate 200 is similarly provided with an electronic circuit arrangement portion 212 in the central portion when viewed in a plan view, and a ground pattern 214 is provided so as to surround the outer side of the electronic circuit arrangement portion 212. The electronic circuit arrangement portion 212 is formed in a region substantially overlapping with the electronic circuit arrangement portion 202 on the upper surface of the substrate 200 when viewed in a plan view. The ground pattern 214 is extended to the vicinity of the edge of the substrate 200 so as to include a region corresponding to the arrangement region of the feed line 206 and the antenna matching circuit 208 on the upper surface of the substrate 200 in addition to the region substantially overlapping with the ground pattern 204 on the upper surface of the substrate 200 when viewed in a plan view. A spring 220 is installed in the extended area of ​​the ground pattern 214. It is desirable that the installation position of the spring 220 is a position corresponding to the connection position of the feed element 430 and the feed line 206 on the upper surface of the substrate 200, or close to the connection position. Specifically, it is desirable to set the distance between the upper surface position where the feeding element 430 and the feeding line 206 are connected on the upper surface of the substrate 200 and the lower surface position where the spring 220 is installed on the lower surface of the substrate 200 to be 3 cm or less. The ground pattern 204 on the upper surface of the substrate 200 and the ground pattern 214 on the lower surface are electrically connected through through holes provided at any plurality of locations and are set to the same ground potential.

[0047] As described above, the antenna element 400, which is the upper edge of the slot 12, is powered from the substrate 200 via the feed element 430 connected to the antenna element 400 and the feed line 206 connected to the feed element 430. The edge 104 of the antenna base 100, which is the lower edge of the slot 12, is grounded by being electrically connected to the ground pattern 214 on the lower surface of the substrate 200 via the antenna base 100 and the spring 220, both of which are made of metal. Thus, the slot 12 operates as a slot antenna.

[0048] The substrate 200 is arranged between the antenna base 100 and the intermediate cover 300. As described above, the substrate 200 is elastically supported by the spring 220, and is fixed above the claw 106 in a manner that the interval between the substrate 200 and the antenna base 100 is maintained. Thus, it can be said that the substrate 200 is fixedly arranged in a manner that it floats in the air, and a gap of a predetermined height is ensured between the antenna base 100 below. Therefore, interference with electronic components mounted on the lower surface of the substrate 200 is suppressed. A gap of a predetermined height is ensured above the substrate 200 by the intermediate cover 300. Thus, interference with electronic components mounted on the upper surface of the substrate 200 is suppressed.

[0049] [Effects]

[0050] The vehicle-mounted antenna device 10 includes an antenna element 400 having a slot 12 formed with the edge 104 of the metal antenna base 100 as an opposing side. Therefore, when the antenna base 100 is arranged in the horizontal direction, the long side direction of the slot 12 is also in the horizontal direction, and the slot 12 can be operated as a slot antenna for vertically polarized waves. The antenna element 400 is powered from the feed line 206 provided on the substrate 200 via the feed element 430. Since the substrate 200 and the antenna base 100 are arranged between the antenna base 100 and the intermediate cover 300 so as to face each other, a sufficient substrate area can be ensured, and the vehicle-mounted antenna device 10 can be made low-profile.

[0051] As a method of feeding the slot antenna, a method using a coaxial cable is known. When the slot antenna is powered by a coaxial cable, the core wire of the coaxial cable is directly connected to a metal plate having a slot to supply power. Therefore, it is impossible to induct the antenna matching circuit for the slot antenna, and it is difficult to increase the number of frequency bands that can be used in the vehicle-mounted antenna device. In order to perform communications in multiple frequency bands such as LTE (Long Term Evolution) communications and / or V2X (Vehicle to X) communications in a vehicle-mounted antenna device that supports vehicle-mounted information services, it is desired to increase the number of frequency bands that can be used in the vehicle-mounted antenna device.

[0052] In the vehicle-mounted antenna device 10 of the present embodiment, since the antenna matching circuit 208 is provided on the substrate 200, the number of frequency bands that can be used in the vehicle-mounted antenna device 10 can be increased. As described above, according to the present embodiment, in the vehicle-mounted antenna device 10 having the antenna element 400 constituting the slot antenna, the number of frequency bands that can be used in the vehicle-mounted antenna device 10 can be increased.

[0053] In addition, the embodiment to which the present invention can be applied is not limited to the above-mentioned embodiment, and it is of course possible to make appropriate changes within the scope not departing from the gist of the present invention.

[0054] (A) Spring

[0055] For example, the structure in which the spring 220 is inserted between the bottom surface 102 of the antenna base 100 and the substrate 200 may be as follows: Figure 8 The structure shown.

[0056] Figure 8 is a diagram showing another example of spring installation. Figure 5 The main part cross-sectional view shown is similarly a main part cross-sectional view of the vehicle-mounted antenna device 10 along the longitudinal direction, and is a schematic diagram in which the outer cover 500 and the intermediate cover 300 are omitted in order to make the electrical connection structure easier to understand. Figure 8 In the example shown, one end of the spring 222 is mounted on the lower surface of the substrate 200 in the region where the ground pattern 214 is formed, and the other end of the spring 222 is connected to the edge 104 of the antenna base 100. The edge 104 and the spring 222 are preferably connected at a position close to the lower edge of the slit 12, that is, the upper edge of the edge 104. The spring 222 can be mounted, for example, at a right angle. In this case, one end of the spring 222 is fixedly mounted to the substrate 200 at a right angle in advance, and the other end of the spring 222 is connected to the edge 104 of the antenna base 100 by soldering when the antenna device is assembled.

[0057] (B) Overall shape of the device

[0058] Although the overall shape of the vehicle-mounted antenna device 10 is a thin rectangular parallelepiped shape, it may be a polygonal shape in a plan view, or may be another shape such as a cylindrical shape or an elliptical cylindrical shape.

[0059] (C) Number of antennas

[0060] Although the vehicle-mounted antenna device 10 has two slot antennas, it may have three or more slot antennas. For example, slot antennas may be disposed on the front side surface and / or the rear side surface, or two or more slot antennas may be disposed on one side surface.

[0061] (D) Feeding element

[0062] One end of the feeding element 430 formed in an L shape in a side view is connected to the lower edge of the antenna element 400 in such a manner that the cross section of the one end is parallel to the plane formed by the up-down direction and the front-back direction. The other end is connected to the feeding line 206 arranged on the substrate 200 in such a manner that the cross section of the other end is parallel to the plane formed by the front-down direction and the left-right direction. However, one end of the feeding element 430 formed in an L shape in a side view may be connected to the lower edge of the antenna element 400 in such a manner that the cross section of the one end is parallel to the plane formed by the front-down direction and the left-right direction. In this case, the other end of the feeding element 430 is connected to the feeding line 206 in such a manner that the cross section of the other end is parallel to the plane formed by the up-down direction and the front-back direction. In addition, one end of the feeding element 430 formed in an L shape in a side view may be connected to the upper surface portion of the antenna element 400 in such a manner that the cross section of the one end is parallel to the plane formed by the front-down direction and the left-right direction. In this case, the other end of the feeding element 430 is connected to the feeding line 206 so that the cross section of the other end is parallel to a plane formed by the up-down direction and the front-rear direction.

[0063] Although the feeding element 430 is formed in an L-shape when viewed from the side, any shape is acceptable as long as the length of the feeding element 430 is short. For example, when the feeding element 430 is a straight plate, the feeding element 430 may be provided parallel to the vertical direction, and one end of the feeding element 430 may be connected to the upper surface of the antenna element 400, and the other end may be connected to the feeding line 206. The connection portion between the one end of the feeding element 430 and the upper surface of the antenna element 400 may be near the slit 14 or may not be near the slit 14.

[0064] Although the feeding element 430 is provided in the antenna element 400 , the feeding element 430 may also be provided in the feeding line 206 .

[0065] (E) Antenna base

[0066] Although the antenna base 100 has the bottom portion 102 and the edge portion 104, the antenna base 100 may have only the bottom portion 102. In this case, when the antenna element 400 is disposed on the intermediate cover 300, a gap 12 is formed between the antenna element 400 and the side end (edge) of the bottom portion 102 of the antenna base 100 facing the antenna element 400.

[0067] The disclosure of this specification can be summarized as follows.

[0068] The scheme of the present invention is a vehicle-mounted antenna device, which includes: an antenna base having a bottom portion; a substrate arranged above the bottom portion and opposite to the bottom portion; and an antenna vibrator arranged on the periphery and forming a slot antenna by using the side ends of the antenna base as opposite sides of the slot.

[0069] According to this scheme, in a vehicle-mounted antenna device having an antenna vibrator constituting a slot antenna, a low profile can be achieved. A slot antenna is formed with the side ends of the antenna base as opposite sides. Therefore, when the bottom portion is arranged in the horizontal direction, the long side direction of the slot of the slot antenna also becomes a direction along the horizontal direction, and a horizontal gain can be obtained as a slot antenna. Since the substrate is arranged above the bottom portion and opposite to the antenna base, a low profile of the vehicle-mounted antenna device can be achieved.

[0070] The substrate may include an antenna matching circuit, and the antenna matching circuit may be arranged close to a feeding portion of the antenna element.

[0071] Thus, the antenna matching circuit can be arranged close to the feeding portion of the antenna element, so that the transmission loss between the slot antenna and the antenna matching circuit can be reduced, thereby maintaining the antenna characteristics of the slot antenna well.

[0072] The antenna element may include a first antenna element disposed on a first direction side and a second antenna element disposed on a second direction side opposite to the first direction side.

[0073] Thus, two slot antennas can be provided in the vehicle-mounted antenna device, and since the two slot antennas face opposite sides to each other, interference between the two slot antennas can be suppressed.

[0074] The substrate may include a feeder line, an electronic circuit arrangement portion, and a ground pattern, and the feeder line may electrically connect the electronic circuit arrangement portion and the antenna element.

[0075] Thus, the feeder line, the electronic circuit arrangement portion, and the ground pattern can be arranged on the substrate, so that the substrate is less susceptible to the influence of noise from the outside and the effect of suppressing the emission of noise to the outside can be obtained.

[0076] An elastic support portion for elastically supporting the substrate with respect to the bottom surface portion may be provided.

[0077] Thus, the elastic support portion can elastically support the substrate relative to the bottom surface portion. Although electronic circuits are often mounted on the upper surface of the substrate, since both surfaces of the substrate can be supported in a state that can be said to be floating, electronic circuits can be mounted on both surfaces of the substrate.

[0078] The elastic support portion may be made of metal, and a ground pattern of the substrate and the antenna base may be electrically connected via the elastic support portion.

[0079] Thus, the ground pattern of the substrate and the antenna base can be electrically connected via the metal elastic support portion.

[0080] The distance between the feeding portion of the antenna element and the portion where the substrate and the elastic support portion come into contact may be 3 cm or less.

[0081] Thus, the feeding portion of the antenna element and the portion in contact with the substrate and the elastic support portion are located close to each other, and in the case of a structure grounded via the elastic support portion, the antenna characteristics of the slot antenna can be well maintained.

[0082] The antenna base may include an edge portion provided to stand upright from the bottom surface portion, and the elastic support portion may be connected to the edge portion.

[0083] Thus, the elastic support portion is connected to the edge portion erected from the bottom surface portion. Since the distance of the ground path can be shortened, the degradation of the antenna characteristics related to the ground path can be reduced.

[0084] The antenna element may include a slit.

[0085] Thus, the antenna element has a slit, and the types of frequency bands that can be used increase compared to a case where the antenna element does not have a slit, and the number of frequency bands that can be used in the vehicle-mounted antenna device can be increased.

[0086] Alternatively, the antenna element is used for in-vehicle information services.

[0087] Thereby, the vehicle-mounted antenna device can cope with the vehicle-mounted information service.

[0088] Description of Reference Numerals

[0089] 1…Vehicle, 3…Roof, 5…Dent, 7…Cover

[0090] 10…In-vehicle antenna device

[0091] 12…slit, 14…slit

[0092] 20…Connector

[0093] 100…Antenna base

[0094] 102 ... bottom portion, 104 ... edge portion

[0095] 200...Substrate

[0096] 202, 212…Electronic circuit configuration department

[0097] 204, 214…ground pattern

[0098] 206 ...feeding circuit, 208 ...antenna matching circuit

[0099] 220…Spring

[0100] 300…Intermediate cover

[0101] 400…Antenna vibrator

[0102] 410 ... first antenna element, 420 ... second antenna element

[0103] 430…Feeding element

[0104] 500…Outer packaging cover.

Claims

1. A vehicle-mounted antenna device, comprising: An antenna base having a bottom portion; a substrate disposed above the bottom portion and opposite to the bottom portion; An intermediate cover covering the substrate; and an antenna element disposed on the outer periphery of the intermediate cover and constituting a slot antenna by using the side ends of the antenna base as opposite sides of the slot, The intermediate cover is formed of a synthetic resin having insulating properties. The antenna element is a metal component formed by performing sheet metal processing on a metal plate, and is a separate component from the intermediate cover.

2. The vehicle-mounted antenna device according to claim 1, wherein: The substrate has an antenna matching circuit, The antenna matching circuit is arranged close to a feeding portion of the antenna element.

3. The vehicle-mounted antenna device according to claim 1 or 2, wherein: The antenna element has: a first antenna element disposed on the first direction side; and A second antenna element is arranged on a second direction side which is opposite to the first direction side.

4. The vehicle-mounted antenna device according to claim 1 or 2, wherein: The substrate has a feed line, an electronic circuit configuration portion, and a ground pattern, The feeder line electrically connects the electronic circuit configuration section and the antenna element.

5. The vehicle-mounted antenna device according to claim 1 or 2, wherein: An elastic support portion is provided for elastically supporting the substrate with respect to the bottom surface portion.

6. The vehicle-mounted antenna device according to claim 5, wherein: The elastic support part is made of metal. The ground pattern of the substrate and the antenna base are electrically connected via the elastic support portion.

7. The vehicle-mounted antenna device according to claim 5, wherein: The distance between the feeding portion of the antenna element and the portion where the substrate and the elastic support portion abut is 3 cm or less.

8. The vehicle-mounted antenna device according to claim 5, wherein: The antenna base has an edge portion erected from the bottom portion. The elastic support portion is connected to the edge portion.

9. The vehicle-mounted antenna device according to claim 1 or 2, wherein: The antenna element has a slit.

10. The vehicle-mounted antenna device according to claim 1 or 2, wherein: The antenna vibrator is used for vehicle-mounted information services.

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