Vehicle antenna

Abstract

To provide an on-vehicle antenna capable of receiving a wide-band electromagnetic wave of which the height is low and it is in compact.SOLUTION: An on-vehicle antenna comprises: a power supply pin 31 that is stood to a body 10; a first radiant element 32 that is extended to a rear side of a vehicle from the power supply pin 31 in a horizontal inner surface; and a second radiant element 35 that is extended to a front side of the vehicle from the power supply pin 31 in the horizontal inner surface. In the first radiant element 32, a first tip end part 32a is fixed to the body 10 via a first insulation member 37. The second radiant element 35 is longer than the first radiant element 32, and a second tip end part 35a is connected to the body 10. An intermediate part 36 between the power supply pin 31 and the second tip end part 35a is fixed to the body 10 via a second insulation member 38.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a vehicle antenna structure that is attached to the body of a vehicle. To make Regarding. [Background technology]

[0002] Various wideband vehicle-mounted antennas have been proposed. For example, Patent Document 1 discloses a vehicle-mounted antenna that integrates a loop antenna, whose element length is approximately 1 / 2 the wavelength of UHF radio waves, and a monopole antenna, whose element length is approximately 1 / 4 the wavelength of VHF radio waves, and feeds each antenna from a common feed point. Patent Document 2 also discloses a wideband antenna that enables impedance matching at the feed point by using a feed element with a diameter of 0.01 wavelength or more and a short-circuit conductor with a diameter of 0.01 wavelength or more. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-13847 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-88198 Summary of the Invention [Problem to be solved by the invention]

[0004] Recently, there has been a demand for vehicles to be equipped with digital televisions (DTVs). In this case, an antenna for receiving the wideband frequency of DTV is installed in the vehicle. To receive the wideband frequency, a method of attaching multiple antennas to the window glass of the vehicle is sometimes used, as disclosed in Patent Document 1. In this case, there is a problem that the antennas are visible to passengers, which is unsightly.

[0005] Therefore, an object of the present disclosure is to provide an in-vehicle antenna that can be positioned so as not to be visible to passengers and that can receive radio waves over a wide band. [Means for solving the problem]

[0006] The vehicle antenna of the present disclosure is an vehicle antenna attached to a body of a vehicle, and comprises: a feed pin erected on the body; a first radiating element extending from the feed pin in a first direction in a horizontal plane; and a second radiating element extending from the feed pin in a second direction opposite to the first direction in the horizontal plane, wherein a first tip of the first radiating element is fixed to the body via a first insulating member; and the second radiating element is longer than the first radiating element, has a second tip connected to the body, and an intermediate portion between the feed pin and the second tip is fixed to the body via a second insulating member.

[0007] As a result, the second radiating element receives radio waves at a higher frequency than the frequency received by the first radiating element and adjusts the input impedance of the vehicle-mounted antenna, thereby achieving impedance matching over a wide bandwidth. Therefore, the vehicle-mounted antenna of the present disclosure can obtain high gain over a wide bandwidth. Furthermore, the vehicle-mounted antenna of the present disclosure has the first radiating element and the second radiating element fixed to the vehicle body via insulating members, respectively, so that mutual coupling occurs between the vehicle body and the first radiating element and between the vehicle body and the second radiating element, allowing it to receive radio waves over a wide bandwidth. Furthermore, the vehicle-mounted antenna of the present disclosure has a compact configuration and can be attached to the vehicle body so as not to be visible to occupants.

[0008] In the vehicle-mounted antenna of the present disclosure, the second radiating element may include a proximal portion close to the feed pin and a distal portion far from the feed pin, the distal portion being thicker than the proximal portion, and the intermediate portion being a portion of the proximal portion on the distal portion side.

[0009] This adjusts the input impedance of the vehicle antenna, enabling impedance matching over a wide bandwidth, thereby increasing gain over a wide bandwidth.

[0010] In the vehicle-mounted antenna of the present disclosure ,before First tip Below The end segment may have an end portion extending in a direction perpendicular to the axis of the shaft, and the end portion may be fixed to the body together with the first tip portion via the first insulating member.

[0011] This adjusts the input impedance of the vehicle-mounted antenna in the low-frequency range received by the first radiating element, achieving impedance matching in the low-frequency range, thereby increasing the gain in the low-frequency range. [Effects of the Invention]

[0016] The vehicle-mounted antenna of the present disclosure has a low, compact configuration, can be positioned so as not to be visible to passengers, and can receive radio waves over a wide band. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is an elevation view showing a vehicle equipped with an in-vehicle antenna according to an embodiment and a rear quarter panel. [Figure 2] 2 is an elevational view showing a cross section taken along line AA in FIG. 1, illustrating a cross section of a rear quarter panel and an in-vehicle antenna. [Figure 3] 2 is a detailed elevational view of part B shown in FIG. 1 with the quarter glass removed. FIG. [Figure 4] 4 is a graph showing a change in voltage standing wave ratio (VSWR) with respect to frequency of the vehicle-mounted antenna of the embodiment. [Figure 5] 5 is a current distribution diagram in the low frequency region G1 and the high frequency region G2 shown in FIG. 4. FIG. [Figure 6] FIG. 10 is an elevation view showing a vehicle-mounted antenna according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, the embodiments will be described with reference to the drawings. In-vehicle antenna 30 mounted did Vehicle 100 and ,car The configuration of the vehicle-mounted antenna 30 attached to the vehicle 100 will now be described. Furthermore, The arrows FR, UP, and RH shown in each figure indicate the front, top, and right sides of the vehicle 100, respectively. The opposite directions of the arrows FR, UP, and RH indicate the rear, bottom, and left sides. Hereinafter, when the directions of front, rear, left, right, and up and down are used in explanations, they will refer to the front and rear in the front-rear direction of the vehicle 100, the left and right in the left-right direction, and the up and down in the up and down direction, unless otherwise specified.

[0019] As shown in FIG. 1, a vehicle 100 includes a body 10 and an on-board antenna 30 attached to the body 10 .

[0020] The body 10 includes a rear quarter panel 11 behind the rear door. The rear quarter panel 11 is provided with a rear quarter window 20. The rear quarter window 20 is composed of a window opening 14 provided in the rear quarter panel 11 and a rear quarter glass 21 attached to the window opening 14. The rear quarter glass 21 is the window glass described in the claims.

[0021] As shown in Figure 2, the rear quarter panel 11 is made up of an outer panel 12 and an inner panel 13. A step 15 is provided around the outer periphery of a window opening 14 in the outer panel 12, recessed from the vehicle outer surface of the outer panel 12 toward the vehicle inner side. A bottom edge 16, a top edge 18, a front vertical edge 17, and a rear vertical edge 19 of the step 15 define the window opening 14. An on-board antenna 30 is attached to the bottom edge 16. The configuration of the on-board antenna 30 will be described later with reference to Figure 3.

[0022] A rear quarter glass 21 is attached to the outer surface of the stepped portion 15 with adhesive 25. As shown in FIG. 1 , the rear quarter glass 21 has a central transparent area 24 and a peripheral masking area 22. The masking area 22 is opaque, for example, colored black. When the rear quarter glass 21 is attached to the stepped portion 15, the lower part of the masking area 22 overlaps the vehicle-mounted antenna 30 in the thickness direction of the rear quarter glass 21. This prevents the vehicle-mounted antenna 30 from being seen from the outside. An interior panel 50 is attached to the interior side of the rear quarter panel 11. A tip portion 51 of the interior panel 50 contacts the masking area 22 on the inner surface of the rear quarter glass 21, covering the vehicle-mounted antenna 30 from the inside of the vehicle 100. This prevents the vehicle-mounted antenna 30 from being seen from inside the vehicle. In this way, the vehicle-mounted antenna 30 is not visible to occupants, improving the aesthetics of the vehicle 100.

[0023] Next, we will explain the on-board antenna 30. As shown in Fig. 3, the on-board antenna 30 is a T-shaped antenna including a feed pin 31, a first radiating element 32, a second radiating element 35, a first insulating member 37, and a second insulating member 38.

[0024] The feed pin 31 is a metal plate-like member erected on the lower side 16 of the window opening 14. The feed pin 31 extends from the lower side 16 toward the upper side of the vehicle. A connector 40 is attached to the lower end of the feed pin 31. A cable for feeding power to the first radiating element 32 and the second radiating element 35 is connected to the connector 40.

[0025] The first radiating element 32 is a thin, rectangular metal plate member that extends from the top of the feed pin 31 toward the rear of the vehicle in a horizontal plane so as to receive horizontally polarized DTV radio waves. The height in the vehicle vertical direction from the bottom side 16 to the top end face of the first radiating element 32 is height H1. Here, the rear of the vehicle is the first direction recited in the claims. A first tip end 32a of the first radiating element 32 at the rear of the vehicle is fixed to the bottom side 16 via a first insulating member 37. The first insulating member 37 is made of resin or the like.

[0026] The second radiating element 35 is a thin, rectangular metal plate member longer than the first radiating element 32. The second radiating element 35 extends from above the feed pin 31 toward the front of the vehicle in a horizontal plane so as to receive horizontally polarized DTV radio waves. Here, the front of the vehicle is the opposite direction to the rear of the vehicle and corresponds to the second direction in the claims. A second tip 35a of the second radiating element 35 at the front of the vehicle is connected to the front vertical side 17 of the window opening 14. The second radiating element 35 includes a proximal portion 33 close to the feed pin 31 and a distal portion 34 farther from the feed pin 31. The thickness of the distal portion 34 is greater than the thickness of the proximal portion 33. The input impedance of the on-board antenna 30 is adjusted by the thickness and height H22 of the distal portion 34. Therefore, the thickness and height H22 of the distal portion 34 are adjusted to achieve impedance matching over a wide band.

[0027] Additionally, an intermediate portion 36 between the power feed pin 31 and the second tip portion 35a is fixed to the lower side 16 via a second insulating member 38. As shown in FIG. 3, the intermediate portion 36 is the portion of the proximal portion 33 on the distal portion 34 side. The height of the upper end surface of the proximal portion 33 from the lower side 16 in the vehicle vertical direction is height H21. The height of the upper end surface of the distal portion 34 from the lower side 16 is height H22.

[0028] 3, when the rear quarter glass 21 is attached to the step portion 15, the height of the lower part of the masking area 22 from the lower edge 16 is height H3. The height H1 of the upper end of the first radiating element 32 from the lower edge 16, the height H21 of the upper end of the proximal portion 33 from the lower edge 16, and the height H22 of the distal portion 34 from the lower edge 16 are all lower than height H3. Therefore, as described above, when the rear quarter glass 21 is attached to the step portion 15, the feed pin 31, the first radiating element 32, and the second radiating element 35 overlap the lower part of the masking area 22 in the thickness direction of the rear quarter glass 21. This makes the in-vehicle antenna 30 invisible from the outside.

[0029] Next, the characteristics of the on-board antenna 30 will be described with reference to FIGS. 4 and 5. As shown in FIG. 4, the first radiating element 32 receives radio waves in the low-frequency region G1, and the second radiating element 35 receives radio waves in the high-frequency region G2. FIG. 5 shows the current distribution in the low-frequency region G1 and the high-frequency region G2 in this case. In FIG. 5, the larger the current, the whiter the color, and the smaller the current, the darker the color. As shown in the left diagram of FIG. 5, in the low-frequency region G1, the first radiating element 32 is white, indicating that the current in the first radiating element 32 is large. Furthermore, in the right diagram of FIG. 5, the proximal portion 33 of the second radiating element 35 is white, indicating that the current in the proximal portion 33 is large. Furthermore, the second radiating element 35 adjusts the input impedance of the on-board antenna 30, enabling impedance matching over a wide bandwidth. Furthermore, by fixing the first tip portion 32a and the intermediate portion 36 to the bottom side 16 via the first and second insulating members 37 and 38, respectively, mutual coupling occurs between the body 10 and the first radiating element 32, and between the body 10 and the second radiating element 35. As a result, even if the vehicle-mounted antenna 30 is configured so that the heights H1, H21, and H22 from the bottom side 16 are lower than the height H3 of the masking area 22 from the bottom side 16, the voltage standing wave ratio (VSWR) between the lower limit frequency F1 and the upper limit frequency F2 of the DTV radio waves can be reduced to less than a predetermined threshold value Rs, as shown in Fig. 4, and the gain of the vehicle-mounted antenna 30 can be increased.

[0030] As described above, the in-vehicle antenna 30 has the first radiating element 32 and the second radiating element 35 receiving the low-frequency region G1 and the high-frequency region G2, respectively, and the second radiating element 35 performs impedance matching over a wide band, and further reduces the voltage standing wave ratio (VSWR) in the DTV frequency range due to mutual coupling between the in-vehicle antenna 30 and the body 10. As a result, the in-vehicle antenna 30 can receive wide-band radio waves with high gain with a compact configuration in which the heights H1, H21, and H22 from the bottom edge 16 are each lower than the height H3 of the masking region 22 from the bottom edge 16, and can be positioned so as not to be seen by occupants.

[0031] Next, a vehicle-mounted antenna 130 according to another embodiment will be described with reference to Fig. 6. The same components as those of the vehicle-mounted antenna 30 previously described with reference to Figs. 1 to 4 are designated by the same reference numerals, and description thereof will be omitted.

[0032] The in-vehicle antenna 130 has an end segment 39 extending downward from the first tip 32a of the first radiating element 32. The end segment 39 is fixed to the lower side 16 together with the first tip 32a via a first insulating member 37. The rest of the configuration is the same as that of the in-vehicle antenna 30 described above.

[0033] By providing the end segment 39, the input impedance of the in-vehicle antenna 30 in the low-frequency region G1 received by the first radiating element 32 is adjusted, and impedance matching in the low-frequency region G1 is achieved. This makes it possible to increase the gain in the low-frequency region G1. Furthermore, like the in-vehicle antenna 30, the in-vehicle antenna 130 is low in height, compact, and capable of receiving radio waves over a wide band.

[0034] In the above description, the first radiating element 32 extends rearward from the feed pin 31, and the second radiating element 35 extends forward from the feed pin 31, but this is not limiting. For example, the first radiating element 32 may extend forward from the feed pin 31, and the second radiating element 35 may extend rearward from the feed pin 31, with the second tip 35a connected to the rear vertical side 19.

[0035] Alternatively, the power supply pin 31 may be erected downward from the upper edge 18 of the window opening 14, the first radiating element 32 may be fixed to the upper edge 18 via a first insulating member 37, and the second radiating element 35 may be fixed to the upper edge 18 via a second insulating member 38.

[0036] In this case, too, when the rear quarter glass 21 is attached to the step portion 15, the upper part of the masking area 22 overlaps with the vehicle-mounted antenna 30 in the thickness direction of the rear quarter glass 21, so that the vehicle-mounted antenna 30 is no longer visible to the occupants, improving the aesthetic appearance of the vehicle 100.

[0037] The in-vehicle antenna 30 may also be attached to a window opening other than the window opening 14 of the rear quarter panel 11. For example, it may be attached to a window opening for a rear window in the rear panel. In this case, the first radiating element 32 and the second radiating element 35 extend in a first direction in the vehicle width direction and a second direction opposite to the first direction. For example, the first radiating element 32 may extend to the right of the vehicle, and the second radiating element 35 may extend to the left of the vehicle.

[0038] Furthermore, the thickness of the distal portion 34 may be adjusted according to the structure of the body 10 to adjust the input impedance of the in-vehicle antenna 30, thereby achieving impedance matching over a wide band. Also, the thickness of the distal portion 34 may be configured to be the same as the thickness of the proximal portion 33.

[0039] In the above explanation, the first radiating element 32 and the second radiating element 35 are described as extending in a horizontal plane, but the horizontal here does not have to be strictly horizontal, as long as it is horizontal enough to be able to receive horizontally polarized DTV radio waves. Therefore, the first radiating element 32 and the second radiating element 35 may extend in a plane that is slightly inclined relative to a strictly horizontal plane.

[0040] Furthermore, in the above description, the vehicle-mounted antennas 30 and 130 have been described as receiving DTV radio waves, but this is not limiting and the invention can also be applied to antennas that transmit and receive radio waves such as WiFi and V2X. [Explanation of symbols]

[0041] 10 body, 11 rear quarter panel, 12 outer panel, 13 inner panel, 14 window opening, 15 step portion, 16 bottom edge, 17 front vertical edge, 18 top edge, 19 rear vertical edge, 20 rear quarter window, 21 rear quarter glass, 22 masking area, 24 transparent area, 25 adhesive, 30, 130 vehicle antenna, 31 feed pin, 32 first radiating element, 33 proximal portion, 34 distal portion, 35 second radiating element, 36 intermediate portion, 37 first insulating member, 38 second insulating member, 39 end segment, 40 connector, 50 interior panel, 51 tip portion, 100 vehicle Both.

Claims

1. An on-board antenna attached to a vehicle body, a power supply pin provided upright on the body; a first radiating element extending in a first direction from the feed pin in a horizontal plane; a second radiating element extending in a second direction opposite to the first direction from the feed pin in a horizontal plane; The first radiating element has a first tip portion fixed to the body via a first insulating member, the second radiating element is longer than the first radiating element, a second tip end is connected to the body, and an intermediate portion between the feed pin and the second tip end is fixed to the body via a second insulating member; An in-vehicle antenna characterized by the above.

2. The vehicle-mounted antenna according to claim 1, the second radiating element includes a proximal portion close to the feed pin and a distal portion far from the feed pin, the distal portion being thicker than the proximal portion, and the intermediate portion being a portion of the proximal portion on the distal portion side; An in-vehicle antenna characterized by the above.

3. The vehicle-mounted antenna according to claim 2, the first tip portion includes an end segment extending downward, and the end segment is fixed to the body together with the first tip portion via the first insulating member; An in-vehicle antenna characterized by the above.

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