Glass antenna for vehicle

Abstract

To provide a glass antenna for a vehicle, constructing a diversity antenna that is used for an electric vehicle, and hardly receives an influence of an electromagnetic noise.SOLUTION: A glass antenna A for a vehicle, provided to an electric vehicle 1 that can be traveled by a driving force of a motor receiving a power supply from a battery, comprises: a glass plate 2 for separating an internal part and an external part of the electric vehicle 1; and a first antenna element 10 that is fixed to a plate surface 2a of the glass plate 2, and can receive an electric wave that is propagated in the air to an external part of the electric vehicle 1. The first antenna element 10 constructs a diversity antenna in cooperation with a second antenna element 20 that can receive the electric wave via a disconnection part 7 that can disconnect an electromagnetic noise discharged from a current transformer arranged between a device to which the power is supplied from the battery and the battery while being provided to the external part of the electric vehicle 1.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a glass antenna for a vehicle. [Background technology]

[0002] Automobiles are equipped with antennas for receiving broadcast waves and for transmitting and receiving various systems. As the automobile moves, the reception conditions of these radio waves change from moment to moment. In such a situation, diversity antennas that receive radio waves with multiple antennas are sometimes used to stabilize the reception conditions of radio waves.

[0003] Patent Document 1 describes a vehicle glass antenna that can receive FM broadcast waves in a good diversity manner even when the space above the defogger on the rear window of the vehicle is narrow by providing two antennas in the space. This vehicle glass antenna is composed of two antennas for FM broadcast waves arranged in the space above the defogger on the rear window of the vehicle, and each antenna has a power supply unit arranged at a distance from the left and right at the upper end of the rear window, a vertical wire connected to the power supply unit and hanging down, and a horizontal wire connected to the lower end of the vertical wire. The horizontal wires of the two antennas are each arranged close to the heating horizontal wire at the top of the defogger and are capacitively coupled to the heating horizontal wire at the top. At least one auxiliary wire for adjusting the directional characteristics is connected to the vertical wire or the power supply unit of at least one of the two antennas.

[0004] Patent Document 2 describes a vehicle glass antenna that is a separate antenna for receiving AM and FM broadcast waves and is provided in the margin of the defogger on the rear window of an automobile, and that can receive FM broadcast waves with high gain and has excellent directional characteristics. This antenna has an AM broadcast wave antenna with a position provided via a lead wire from a plurality of horizontal wires spaced apart from each other and an AM broadcast wave feed point provided at the top horizontal wire, and an FM broadcast wave antenna that extends in a clockwise and counterclockwise direction from two FM feed points provided on both the left and right sides of the AM feed point along a part of the outermost circumference of the AM broadcast wave antenna. This FM broadcast wave antenna is configured to effectively perform diversity reception by extending the lengths of the pair of second vertical wires on the left and right sides in different directions.

[0005] Patent Document 3 describes a glass antenna for vehicles (a diversity glass antenna for automobiles in Patent Document 3) suitable for receiving AM broadcasts, FM broadcasts, and television broadcasts. This glass antenna has a first antenna conductor capacitively coupled to a defogger on the rear window of the automobile and a second antenna conductor not capacitively coupled to the defogger, connects the second antenna conductor to the defogger through a capacitor selected to have high impedance in the AM broadcast wave band, and performs diversity reception with the first antenna conductor and the second antenna conductor. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2012-248981 A [Patent Document 2] JP 2010-109958 A [Patent Document 3] Japanese Patent Application Publication No. 9-130120 Summary of the Invention [Problem to be solved by the invention]

[0007] Recently, the number of automobiles equipped with motors as a driving source (such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), battery electric vehicles (BEVs), and fuel cell electric vehicles (FCEVs), hereinafter also referred to as "electric vehicles") has been increasing. In electric vehicles, a high-voltage battery is arranged inside the electric vehicle, and a DC-DC converter is used to obtain voltage for operating various on-board electronic devices, but electromagnetic noise generated during voltage conversion interferes with signal reception by a diversity antenna. The vehicle glass antennas described in Patent Documents 1 to 3 each have two antennas for diversity reception arranged on the rear window of the automobile.

[0008] Recent diversity antennas use a phase diversity method for processing received signals, which calculates interference from the difference between the received signals of two antennas and subtracts the interference from the received signals of the two antennas. For this reason, it is preferable that the performance difference between the two antennas that make up the diversity reception, that is, the difference in the strength of the received signals, is not too large. On the other hand, it is not preferable for the distance between the two antennas to be too close. If the distance is too close, the difference between the received signal and interference at each antenna will be small, which may make it difficult to calculate the interference.

[0009] Therefore, there is a demand for a vehicle glass antenna that constitutes a diversity antenna for use in electric vehicles and is less susceptible to the effects of electromagnetic noise. [Means for solving the problem]

[0010] One embodiment of the vehicle glass antenna according to the present invention is a vehicle glass antenna provided on an electric vehicle that can run by the driving force of a motor supplied with power from a battery, and includes a glass plate that separates the inside and outside of the electric vehicle, and a first antenna element that is fixed to a plate surface of the glass plate and is capable of receiving radio waves propagating through the air outside the electric vehicle, and the first antenna element is provided on the outside of the electric vehicle via a blocking section that can block electromagnetic noise emitted from a transformer that is arranged between the battery and a device that receives power from the battery, and cooperates with a second antenna element that can receive the radio waves to form a diversity antenna.

[0011] According to this embodiment, the vehicle glass antenna includes a glass plate that separates the inside and outside of the electric vehicle, and a first antenna element that can receive radio waves propagating through the air outside the electric vehicle. The first antenna element is provided outside the electric vehicle through a cut-off section that can cut off electromagnetic noise emitted from a transformer that is arranged between the battery and a device that receives power from the battery, and cooperates with a second antenna element that can receive radio waves to form a diversity antenna. In this way, the first antenna element fixed to the plate surface of the glass plate cooperates with the second antenna element that receives radio waves through a cut-off section that can cut off electromagnetic noise to form a diversity antenna, so that the first antenna element is less susceptible to the influence of electromagnetic noise from the transformer of the electric vehicle and can receive radio waves stably.

[0012] In another embodiment of the glass antenna for a vehicle according to the present invention, the blocking portion is made of a metal plate.

[0013] According to this embodiment, since the blocking portion is made of metal, it is possible to reliably block electromagnetic noise emitted from the transformer and suppress the effect of the electromagnetic noise on the second antenna element.

[0014] In another embodiment of the glass antenna for vehicles according to the present invention, the blocking portion is a metal exterior panel of the electric vehicle.

[0015] According to this embodiment, when the blocking portion is a metal exterior panel of the electric vehicle, there is no need to provide a separate structure for blocking electromagnetic noise, and the electric vehicle can be manufactured at low cost.

[0016] In another embodiment of the glass antenna for a vehicle according to the present invention, the diversity antenna is used for a phase diversity receiving method.

[0017] According to this embodiment, if the diversity antenna employs a phase diversity receiving method, radio waves can be received stably even in a location where multipath fading is likely to occur, such as a canyon between buildings.

[0018] In another embodiment of the glass antenna for a vehicle according to the present invention, the frequency band includes a frequency band used for FM radio broadcasting.

[0019] According to this embodiment, FM radio broadcasts can be received stably.

[0020] In another embodiment of the vehicle glass antenna according to the present invention, the second antenna element has a power supply portion and an element, and is arranged in the order of the power supply portion and the element in a direction away from the blocking portion.

[0021] According to this embodiment, the performance of the second antenna element is improved, and radio waves can be received stably.

[0022] In another embodiment of the glass antenna for a vehicle according to the present invention, the first antenna element is disposed at a position capable of being capacitively coupled with the metal exterior panel.

[0023] According to this embodiment, the reception performance of the first antenna element can be changed by changing the coupling capacitance between the first antenna element and the metal exterior panel.

[0024] In another embodiment of the glass antenna for a vehicle according to the present invention, the first antenna element has a receiving gain equal to that of the second antenna element.

[0025] According to this embodiment, if the reception gains of the first antenna element and the second antenna element are equal, the diversity antenna performance can be fully utilized, and radio waves can be received stably.

[0026] In another embodiment of the vehicle glass antenna according to the present invention, an outer edge portion of the glass plate is fixed so as to cover an opening area formed in the metal exterior panel of the electric vehicle, and the first antenna element includes a horizontal element arranged perpendicular to the opening edge of the opening area in the left-right direction of the electric vehicle and at a distance along the plate surface of the glass plate of 20 mm or less.

[0027] According to this embodiment, by arranging the horizontal element perpendicular to the left-right direction of the electric vehicle and at a distance of 20 mm or less along the surface of the glass plate, the receiving gain with the second antenna element can be made equivalent, enabling stable reception of radio waves.

[0028] In another embodiment of the glass antenna for a vehicle according to the present invention, the horizontal element is disposed on the central side of the glass plate with respect to the opening edge of the opening region.

[0029] According to this embodiment, by arranging the horizontal element toward the center of the glass plate relative to the opening edge of the opening area, the reception gain can be made equal to that of the second antenna element, enabling stable reception of radio waves.

[0030] In another embodiment of the glass antenna for a vehicle according to the present invention, the horizontal element is disposed on the outer edge side of the glass plate with respect to the opening edge of the opening region.

[0031] According to this embodiment, by arranging the horizontal element on the outer edge side of the glass plate relative to the opening edge of the opening area, the receiving gain can be made equal to that of the second antenna element, enabling stable reception of radio waves.

[0032] In another embodiment of the glass antenna for a vehicle according to the present invention, the glass plate is a rear glass of the electric vehicle, and the blocking portion is a roof.

[0033] According to this embodiment, when the glass plate is the rear glass of an electric vehicle and the blocking part is the roof, the first antenna element does not interfere with driving, no special configuration is required for the blocking part to block electromagnetic noise, radio waves can be received stably, and the electric vehicle can be manufactured inexpensively.

[0034] In another embodiment of the glass antenna for a vehicle according to the present invention, the first antenna element is disposed below the rear glass in the up-down direction.

[0035] According to this embodiment, it is possible to provide an appropriate distance between the first antenna element and the second antenna element, thereby making it possible to fully utilize the diversity antenna performance and stably receive radio waves. [Brief description of the drawings]

[0036] [Figure 1] 1 is a side view showing an electric vehicle using a vehicle glass antenna according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a front view showing a glass antenna for a vehicle. [Diagram 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. [Figure 4]FIG. 11 is a front view showing another vehicle glass antenna. [Figure 5a] FIG. 11 is a front view showing the configuration of another vehicle glass antenna. [Figure 5b] 1 is a graph showing the difference in reception gain between an antenna element and a shark fin antenna in the domestic reception frequency band. [Figure 6a] FIG. 11 is a front view showing the configuration of another vehicle glass antenna. [Figure 6b] FIG. 11 is a front view showing the configuration of another vehicle glass antenna. [Figure 6c] 1 is a graph showing a difference in reception gain between an antenna element and a shark fin antenna in a reception frequency band. [Figure 7a] FIG. 11 is a front view showing the configuration of another vehicle glass antenna. [Figure 7b] 1 is a graph showing a difference in reception gain between an antenna element and a shark fin antenna in a reception frequency band. [Figure 8a] FIG. 11 is a front view showing the configuration of another vehicle glass antenna. [Figure 8b] 1 is a graph showing a difference in reception gain between an antenna element and a shark fin antenna in a reception frequency band. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] Hereinafter, embodiments of the glass antenna for vehicles according to the present invention will be described in detail with reference to the drawings. Note that the embodiments described below are merely examples for explaining the present invention, and the present invention is not limited to these embodiments. Therefore, the present invention can be embodied in various forms without departing from the gist of the present invention.

[0038] As shown in Figs. 1 and 2, a glass antenna A for vehicles according to the present invention is used in an automobile (such as a hybrid electric vehicle (HEV), plug-in hybrid electric vehicle (PHEV), battery electric vehicle (BEV), or fuel cell electric vehicle (FCEV)) equipped with a motor 3 as a driving source for traveling. Hereinafter, these automobiles are collectively referred to as an electric vehicle 1. Hereinafter, the up-down direction of the electric vehicle 1 is defined as the X direction, and the left-right direction with respect to the traveling direction is defined as the Y direction. The upper side of the electric vehicle 1 in the X direction is defined as the X1 side, and the lower side is defined as the X2 side. Also, the right side with respect to the traveling direction in the Y direction is defined as the Y1 side, and the left side is defined as the Y2 side.

[0039] The electric vehicle 1 is equipped with a battery 4 that supplies power to a motor 3 that is a driving source for traveling. The output voltage of the battery 4 is several hundred volts DC. Therefore, in order to supply power from the battery 4 to an on-board electronic device 6 (one example of an equipment, for example, a car navigation system, a radio, and an audio device) that is mounted on the electric vehicle 1 and operates at a low voltage such as 12 V DC, it is necessary to step down the output of the battery 4 using a DC-DC converter 5 (one example of a transformer). The DC-DC converter 5 radiates electromagnetic noise due to switching for this step-down. This electromagnetic noise may adversely affect the reception of radio waves propagating through the air outside the electric vehicle 1 by an antenna provided on the electric vehicle 1. The outside of the electric vehicle 1 is the outer space on the opposite side to the vehicle interior 1a with respect to a metal exterior panel 7 (one example of a cutoff part, a metal plate) of the electric vehicle 1. Hereinafter, the inner space including the vehicle interior 1a located on the opposite side to the outside with respect to the metal exterior panel 7 is referred to as the inside of the electric vehicle 1.

[0040] In the present embodiment, a diversity antenna is used for the antenna in order to stably receive radio waves in response to the changing radio wave reception conditions while the electric vehicle 1 is traveling. The diversity antenna in this embodiment is configured to cooperate with a vehicle glass antenna A and a shark fin antenna 20 (an example of a second antenna element). The diversity antenna uses a phase diversity method that can combine desired waves and remove multipath fading by adjusting the amplitude and phase of the radio waves (received signals) received by the vehicle glass antenna A and the shark fin antenna 20, respectively. This can improve the quality of the received signal. The diversity antenna in this embodiment is configured to be able to receive a frequency band used in particular for FM radio broadcasting. The principle of the diversity antenna of the phase diversity method is publicly known, so a detailed description will be omitted. Note that in Figs. 1 to 4, except for the shark fin antenna 20 shown in Fig. 3, the transmission line 26 that connects the FM radio receiver included in the in-vehicle electronic device 6 to the vehicle glass antenna A and the shark fin antenna 20 is omitted.

[0041] The glass antenna A for a vehicle includes a rear window 2 (an example of a glass plate) of an electric vehicle 1, and an antenna element 10 (an example of a first antenna element) fixed to an inner surface 2a (an example of a plate surface) of the rear window 2 (see FIG. 3). The shark fin antenna 20 is disposed on a roof 7c (an example of a blocking portion, a metal plate) formed by a metal exterior panel 7 of the vehicle in order to reduce adverse effects from electromagnetic noise generated from inside the electric vehicle 1. This makes it possible to block electromagnetic noise radiated by the DC-DC converter 5, so that the shark fin antenna 20 can stably receive radio waves propagating through the air outside.

[0042] 2, the rear glass 2 is attached to a metal exterior panel 7 of the electric vehicle 1 by applying an adhesive to an outer edge portion 2b of an inner surface 2a located inside the electric vehicle 1. In other words, the part of the rear glass 2 through which light passes is an inner region 7b (an example of an opening region) of a window frame 7a (an example of an opening edge) formed in the metal exterior panel 7. Here, the window frame 7a means the outer edge of the inner region 7b of the metal exterior panel 7. In other words, the window frame 7a means the boundary between the metal exterior panel 7 and the inner region 7b of the metal exterior panel 7.

[0043] The antenna element 10 is formed by baking a conductive material such as silver paste printed on the inner surface 2a of the rear window 2. As shown in FIG. 2 and FIG. 3, the antenna element 10 has a linear shape extending along the X direction, and includes a power supply unit 12 and a horizontal conductor 14 (an example of a horizontal element) along the X direction. The power supply unit 12 of the antenna element 10 of this embodiment is disposed outside the defog area 2c of the inner surface 2a of the rear window 2 and inside the window frame 7a. The horizontal conductor 14 is disposed outside the defog area 2c formed on the inner surface 2a of the rear window 2 and outside the window frame 7a. That is, as shown in FIG. 2, when the electric vehicle 1 is viewed forward from the rear, the horizontal conductor 14 of the antenna element 10 is disposed so as to overlap the metal exterior panel 7. In other words, the horizontal conductor 14 of the antenna element 10 is disposed on the side of the outer edge portion 2b of the rear window 2 with respect to the window frame 7a, which is the outer edge of the inner region 7b.

[0044] In Fig. 3, the antenna element 10 formed on the inner surface 2a of the rear glass 2 and the metal exterior panel 7 are spaced apart, but this is because the thickness of the adhesive layer 8 that bonds the rear glass 2 and the metal exterior panel 7 is thicker than the thickness of the antenna element 10. In Fig. 3, the thicknesses of the antenna element 10 and the adhesive layer 8 are exaggerated. In reality, the thickness of the antenna element 10 is approximately 3 µm to 30 µm, and the thickness of the adhesive layer 8 is approximately 1 mm to 15 mm.

[0045] The horizontal conductor 14 is divided into two, the horizontal conductor 14 arranged on the Y1 side is called the first horizontal conductor 14a (an example of a horizontal element), and the horizontal conductor 14 arranged on the Y2 side is called the second horizontal conductor 14b (an example of a horizontal element). The power supply unit 12 is connected to the end on the Y1 side of the first horizontal conductor 14a. The power supply unit 12 is not connected to the second horizontal conductor 14b. Each of the horizontal conductors 14 extends from the end in the Y direction of the rear glass 2 to the center, but the tips on the center side are spaced apart from each other. As described above, the horizontal conductor 14 of the antenna element 10 and the metal exterior panel 7 are spaced apart, but the horizontal conductor 14 of the antenna element 10 is capacitively coupled to the metal exterior panel 7.

[0046] As another embodiment, the horizontal conductor 14 of the antenna element 10 may be disposed outside the defog region 2c of the inner surface 2a of the rear window 2 and inside the window frame 7a, as shown in Fig. 4. In this case, when the electric vehicle 1 is viewed from the rear to the front, the horizontal conductor 14 of the antenna element 10 does not overlap the metal exterior panel 7. In other words, the horizontal conductor 14 of the antenna element 10 is disposed on the center side in the X direction of the rear window 2 with respect to the window frame 7a, which is the outer edge of the inner region 7b. Even when the horizontal conductor 14 of the antenna element 10 is disposed in such a position, the horizontal conductor 14 of the antenna element 10 is capacitively coupled to the metal exterior panel 7.

[0047] As shown in Figs. 1 to 4, the shark fin antenna 20 is disposed outside the electric vehicle 1 with respect to the roof 7c of the metal exterior panel 7. As shown in Fig. 3, the shark fin antenna 20 includes a power supply unit 22, an antenna unit 24 (one example of an element) connected to the power supply unit 22, and a transmission line 26 for transmitting received radio waves to the in-vehicle electronic device 6. In the shark fin antenna 20 of this embodiment, the power supply unit 22 and the antenna unit 24 are disposed in this order from the roof 7c (metal exterior panel 7) outside the electric vehicle 1 toward a direction away from the roof 7c. Since the shark fin antenna 20 is disposed outside the electric vehicle 1 with respect to the roof 7c, electromagnetic noise generated from inside the electric vehicle 1 (particularly the DC-DC converter 5) is blocked by the roof 7c, and radio waves can be stably received. The roof 7c may be a sunroof or may be composed of only a metal plate. When the roof 7c is a sunroof, it is preferable that the shark fin antenna 20 is disposed on the metal exterior panel 7 other than the glass portion.

[0048] In order to stably receive radio waves in a diversity antenna of the phase diversity system, it is necessary to reduce the difference (hereinafter simply referred to as the gain difference) in the reception performance (reception gain) between the antenna element 10 and the shark fin antenna 20 of the vehicle glass antenna A in the desired frequency band (76 MHz to 108 MHz used for FM radio broadcasting in this embodiment. Hereinafter, this frequency band is also referred to as the reception frequency band). Specifically, the gain difference between the antenna element 10 and the shark fin antenna 20 needs to be within ±15 dB over the entire reception frequency band, preferably within ±10 dB, and more preferably within ±5 dB. If the gain difference between the antenna element 10 and the shark fin antenna 20 is within ±5 dB over the entire reception frequency band, it can be said that the reception gains of the antenna element 10 and the shark fin antenna 20 are equivalent.

[0049] It is difficult to change the reception performance of the shark fin antenna 20 due to the shape constraints. On the other hand, since the antenna element 10 is capacitively coupled with the metal exterior panel 7 as described above, the reception performance of the antenna element 10 can be changed by changing the distance d between the horizontal conductor 14 of the antenna element 10 and the window frame 7a of the metal exterior panel 7 in a direction perpendicular to the Y direction and along the inner surface 2a of the rear window 2 (hereinafter referred to as the inner surface direction) to change the coupling capacitance. The reference for the distance d (where d=0) is the point where the normal to the rear window 2 contacts the window frame 7a, as shown in FIG. 3. In order to reduce the difference in reception gain between the antenna element 10 and the shark fin antenna 20, the distance d between the horizontal conductor 14 of the antenna element 10 and the window frame 7a is preferably within ±20 mm in the inner surface direction with respect to the reference. If it is within this range, the difference in reception gain with the shark fin antenna 20 can be reduced. In the following, when the separation distance d is displayed as a plus sign, it indicates that the device is disposed outside the defog area 2c on the inner surface 2a of the rear window 2 and inside the window frame 7a, as shown in Fig. 4. When the separation distance d is displayed as a minus sign, it indicates that the device is disposed outside the defog area 2c on the inner surface 2a of the rear window 2 and outside the window frame 7a, as shown in Figs. 2 and 3.

[0050] The receiving frequency band of 76 MHz to 108 MHz is roughly divided into a domestic receiving frequency band of 76 to 96 MHz and an overseas receiving frequency band of 88 MHz to 108 MHz. Figures 5 to 8 show the gain difference between the shark fin antenna 20 and the antenna element 10 of the vehicle glass antenna A when the separation distance d between the horizontal conductor 14 of the antenna element 10 and the window frame 7a is changed in the receiving frequency band.

[0051] 5a, 6a, 6b, 7a, and 8a show the configuration of a diversity antenna in which the shape of the horizontal conductor 14 of the antenna element 10 of the vehicle glass antenna A and the distance d from the window frame 7a are changed. The antenna element 10 shown in FIG. 5a, FIG. 6a, FIG. 6b, and FIG. 7a is for the domestic reception frequency band, and the antenna element 10 shown in FIG. 8a is for the overseas reception frequency band. FIG. 5b, FIG. 6c, FIG. 7b, and FIG. 8b show the gain difference when using a diversity antenna including each antenna element 10. Hereinafter, when distinguishing between these five types of antenna elements 10, the antenna element 10 shown in FIG. 5a is referred to as antenna element 10a. The antenna elements 10 shown in FIG. 6a and FIG. 6b are referred to as antenna element 10b and antenna element 10c, respectively. The antenna element 10 shown in FIG. 7a is referred to as antenna element 10d. The antenna element 10 shown in FIG. 8a is referred to as antenna element 10e. In any of antenna elements 10a to 10e, power supply unit 12 is disposed outside defog area 2c on inner surface 2a of rear window 2 and inside window frame 7a.

[0052] FIG. 5a shows an antenna element 10a in which the distance d between the first horizontal conductor 14a arranged on the Y1 side and the window frame 7a is +45 mm, and part of the heating wire in the defog area 2c is made into the horizontal conductor 14. FIG. 5b shows the gain difference when the antenna element 10a is used. Hereinafter, the horizontal conductor 14 made of part of the heating wire in the defog area 2c is referred to as the third horizontal conductor 14c (an example of a horizontal element). The third horizontal conductor 14c extends downward from the center of the defog area 2c, and extends horizontally in both left and right directions from the extending end. The distance d between the third horizontal conductor 14c and the window frame 7a is +25 mm. The tip of the part of the third horizontal conductor 14c extending to the right overlaps the tip of the first horizontal conductor 14a in the vertical direction (X direction).

[0053] In the antenna element 10a shown in Fig. 5a, as shown in Fig. 5b, the gain difference exceeds +15 dB at 80 MHz to 84 MHz in the domestic reception frequency band of 76 MHz to 96 MHz. Therefore, the antenna element 10a is not suitable for use as a diversity antenna for domestic FM radio broadcasts.

[0054] Fig. 6a shows antenna element 10b in which the distance d between horizontal conductor 14 (first horizontal conductor 14a) arranged on the Y1 side and window frame 7a is set to +10 mm. Fig. 6b shows antenna element 10c in which the distance d is set to -10 mm. Fig. 6c shows the gain difference when antenna element 10b and antenna element 10c are used.

[0055] In the antenna element 10b shown in Fig. 6a, the gain difference is within ±15 dB over the entire domestic reception frequency band from 76 MHz to 96 MHz, as shown in Fig. 6c. Therefore, the antenna element 10b can be used as a diversity antenna for domestic FM radio broadcasts.

[0056] In the antenna element 10c shown in Fig. 6b, the gain difference is within ±7 dB over the entire domestic reception frequency band, as shown in Fig. 6c. Therefore, the antenna element 10c can be used as a diversity antenna for domestic FM radio broadcasts, which has better reception performance than the antenna element 10b.

[0057] FIG. 7a shows an antenna element 10d having a horizontal conductor 14 (first horizontal conductor 14a) arranged on the Y1 side with a distance d between the window frame 7a and the horizontal conductor 14 (first horizontal conductor 14a) arranged on the Y1 side and a horizontal conductor 14 (second horizontal conductor 14b) connected to a busbar 2d on the Y2 side among the busbars 2d arranged outside the defog area 2c that supply power to the heating wires of the defog area 2c. FIG. 7b shows a gain difference when the antenna element 10d is used. The second horizontal conductor 14b in FIG. 7a extends downward from the busbar 2d on the Y2 side and extends along the Y direction toward the center (Y1 side) of the rear window 2 at a position where the distance d between the second horizontal conductor 14b and the window frame 7a is −8 mm. Then, it is folded back 180 degrees near the center of the rear window 2 and extends toward the Y2 side. This folded-back portion is spaced from the window frame 7a by a distance d of +7 mm, and extends from the end of the rear glass 2 on the Y2 side to a position about one-third of the left-right length of the rear glass 2 inward.

[0058] In the antenna element 10d shown in Fig. 7a, the gain difference is within ±5 dB over the entire domestic reception frequency band as shown in Fig. 7b. Therefore, the antenna element 10d can be used as an optimal diversity antenna for domestic FM radio broadcasts, which has better reception performance than the antenna elements 10b and 10c.

[0059] FIG. 8a shows an antenna element 10e having a horizontal conductor 14 (first horizontal conductor 14a) arranged on the Y1 side with a distance d between the window frame 7a and the horizontal conductor 14 (second horizontal conductor 14b) connected to the busbar 2d on the Y2 side among the busbars 2d arranged outside the defog area 2c. FIG. 8b shows the gain difference when the antenna element 10e is used. The second horizontal conductor 14b in FIG. 8a extends downward from the busbar 2d on the Y2 side, and extends along the Y direction toward the center (Y1 side) of the rear window 2 at a position where the distance d between the window frame 7a and the horizontal conductor 14 is -7 mm. This configuration is adjusted so that the gain difference is small in the overseas reception frequency band of 88 MHz to 108 MHz.

[0060] In the antenna element 10e shown in Fig. 8a, the gain difference is within ±5 dB over the entire overseas receiving frequency band as shown in Fig. 8b. Therefore, the antenna element 10e can be used as an optimal diversity antenna for overseas FM radio broadcasts.

[0061] Other embodiments Next, the configuration of the antenna, including the glass antenna A for a vehicle according to another embodiment of the present invention will be described. In this embodiment, the configuration of the antenna, etc. is different from that of the above embodiment. Other than that, the configuration is the same as that of the above embodiment. Therefore, in the description of this embodiment, the same reference numerals are used for the parts of the configuration that are the same as those of the above embodiment, and detailed description of the similar configuration is omitted.

[0062] (1) In the above embodiment, the shark fin antenna 20 has been described as one of the antennas constituting the diversity antenna of the phase diversity system, but the present invention is not limited to this. For example, an antenna of any shape can be used at any location on the electric vehicle 1, such as a rod antenna, an antenna built into the rear spoiler, or an antenna built into the rear wing, as long as a diversity antenna can be formed between the antenna and the vehicle glass antenna A. However, it is preferable to place the antenna in a position where electromagnetic noise generated from inside the electric vehicle 1 (particularly the DC-DC converter 5) is blocked by the metal exterior panel 7.

[0063] (2) In the above embodiment, the horizontal conductor 14 of the antenna element 10 extends along the X direction, but may extend at an angle with respect to the X direction. In this case, the horizontal conductor 14 may be configured to intersect with the window frame 7a of the metal exterior panel 7 when the electric vehicle 1 is viewed from the rear to the front.

[0064] (3) In the above embodiment, the antenna element 10 is disposed below the rear window 2 in the X direction (X2 side). However, it may be configured to be disposed above the rear window 2 (X1 side). [Industrial Applicability]

[0065] The present invention can be used for a glass antenna for a vehicle. [Explanation of symbols]

[0066] 1: Electric vehicles 2: Rear glass (glass plate) 2a:Inner surface (plate surface) 2b: Outer edge 3: Motor 4: Battery 5: DC-DC converter (transformer) 6:In-vehicle electronic equipment (equipment) 7: Metal exterior panel (blocking part, metal plate) 7a: Window frame (opening edge) 7b: Internal area (opening area) 7c: Roof (blocking part, metal plate) 10: Antenna element (first antenna element) 10a: Antenna element (first antenna element) 10b: Antenna element (first antenna element) 10c: Antenna element (first antenna element) 14: Horizontal conductor (horizontal element) 14a: First horizontal conductor (horizontal element) 14b: Second horizontal conductor (horizontal element) 14c: Third horizontal conductor (horizontal element) 20: Shark fin antenna (second antenna element) 22: Power supply unit 24: Antenna part (element) A: Vehicle glass antenna

Claims

1. A glass antenna for a vehicle is provided on an electric vehicle that can run by a driving force of a motor supplied with power from a battery, A glass plate separating the inside and the outside of the electric vehicle; a first antenna element fixed to a plate surface of the glass plate and capable of receiving radio waves propagating through the air outside the electric vehicle; The first antenna element is provided outside the electric vehicle via a blocking section capable of blocking electromagnetic noise emitted from a transformer arranged between the battery and an equipment supplied with power from the battery, and cooperates with a second antenna element capable of receiving the radio waves to form a diversity antenna.

2. 2. The glass antenna for a vehicle according to claim 1, wherein the blocking portion is made of a metal plate.

3. 3. The glass antenna for vehicles according to claim 2, wherein the blocking portion is a metal exterior panel of the electric vehicle.

4. 4. The glass antenna for a vehicle according to claim 1, wherein the diversity antenna is used for a phase diversity receiving system.

5. 4. The glass antenna for a vehicle according to claim 1, wherein the radio waves include a frequency band used for FM radio broadcasting.

6. The second antenna element has a power feed portion and an element, 4. The glass antenna for a vehicle according to claim 1, wherein the power supply portion and the element are arranged in this order in a direction away from the blocking portion.

7. 4. The glass antenna for a vehicle according to claim 3, wherein the first antenna element is disposed at a position capable of being capacitively coupled with the metal exterior panel.

8. 8. The glass antenna for a vehicle according to claim 7, wherein the first antenna element has a receiving gain equal to that of the second antenna element.

9. an outer edge portion of the glass plate is fixed so as to cover an opening area formed in the metal exterior panel of the electric vehicle; 9. The glass antenna for a vehicle according to claim 8, wherein the first antenna element includes a horizontal element arranged perpendicular to an opening edge of the opening region in the left-right direction of the electric vehicle and at a distance along the plate surface of the glass plate of 20 mm or less.

10. 10. The glass antenna for a vehicle according to claim 9, wherein the horizontal element is disposed closer to the center of the glass plate than the edge of the opening region.

11. 10. The glass antenna for a vehicle according to claim 9, wherein the horizontal element is disposed on the outer edge side of the glass plate with respect to the opening edge of the opening region.

12. 10. The glass antenna for a vehicle according to claim 9, wherein the glass plate is a rear glass of the electric vehicle, and the blocking portion is a roof.

13. The glass antenna for a vehicle according to claim 12, wherein the first antenna element is disposed below the rear glass in a vertical direction.

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