Window antenna for a vehicle, window pane for a vehicle and antenna system for a vehicle

Abstract

A window antenna (103, 104, 105) for a vehicle, which is provided on a window pane (1) attached to a window frame (2) of a vehicle body and can receive a vertically polarized electromagnetic wave in a first frequency band and a horizontally polarized electromagnetic wave in a second frequency band, the window antenna (103, 104, 105) for a vehicle comprising: a supply electrode (3) configured to supply power; a first element (10) extending from the supply electrode (3) in a direction toward a frame edge (2a) of the window frame (2) or in a direction away from the frame edge (2a); a second element (20) extending from the first element (10) along the frame edge (2a); a third element (30) extending along the second element (20); and a fourth element (40) extending from the feed electrode (3) in a direction towards the frame edge (2a) or in a direction away from the frame edge (2a), wherein a length of the first element (10) is shorter than a length of the second element (20), and the third element (30) extends from the fourth element (40), and a length of the third element (30) is longer than a length of the fourth element (40).

Description

Background of the invention 1. Field of the invention

[0001] The present invention relates to a window antenna for a vehicle, a window pane for a vehicle and an antenna system for a vehicle. 2. Description of the state of the art

[0002] With a variety of antennas (window antennas) for various frequency bands, such as AM broadcasting, FM broadcasting, DAB (Digital Audio Broadcasting), remote keyless entry, digital TV broadcasting, 5G communications, and the like, it is desirable to provide them on a single window glass of a motor vehicle. However, installing various types of antennas on a single window glass of a motor vehicle requires considerable effort. Therefore, window antennas capable of receiving electromagnetic waves in multiple frequency bands have been developed (see, for example, Japanese Patent Laid-Open Publication No. 2015-142162).

[0003] JP 2012-085 153 A describes an antenna, in particular a glass antenna, which is suitable for receiving terrestrial digital radio waves (DAB: Digital Audio Broadcasting) and is mounted on a vehicle window. Summary of the invention

[0004] The claimed invention is defined by the independent claims, while preferred embodiments form the subject matter of the dependent claims. Problems to be solved by the invention

[0005] However, conventional disc antennas cannot easily receive electromagnetic waves in multiple bands unless elements are folded back or bent back.

[0006] Therefore, the present disclosure provides a glass antenna for a vehicle, a window glass for a vehicle, and an antenna system for a vehicle that can receive electromagnetic waves in multiple bands regardless of whether a member is folded back or folded back. Means to solve the problems

[0007] The present disclosure provides a window antenna for a vehicle that is provided on a window pane attached to a window frame of a vehicle body and can receive a vertically polarized electromagnetic wave in a first frequency band and a horizontally polarized electromagnetic wave in a second frequency band, the window antenna for a vehicle including: a feed electrode arranged along a frame edge of the window frame and configured to supply power; a ground electrode arranged along the frame edge of the window frame and configured to provide a ground potential; a first element extending from the feed electrode in a direction toward the frame edge or in a direction away from the frame edge; a second element extending from the first element along the frame edge in a direction away from the ground electrode;and a grounding element extending from the grounding electrode along the frame edge in a direction away from the feed electrode, wherein a length of the first element is shorter than a length of the second element.

[0008] The present disclosure provides a window antenna for a vehicle that is provided on a window pane attached to a window frame of a vehicle body and can receive a vertically polarized electromagnetic wave in a first frequency band and a horizontally polarized electromagnetic wave in a second frequency band, the window antenna for a vehicle including: a feed electrode configured to supply power, a first element extending from the feed electrode in a direction toward a frame edge of the window frame or in a direction away from the frame edge, a second element extending from the first element along the frame edge, a third element extending along the second element, and a fourth element extending from the feed electrode in a direction toward the frame edge or in a direction away from the frame edge,wherein a length of the first element is shorter than a length of the second element and the third element extends from the fourth element and a length of the third element is longer than a length of the fourth element.,

[0009] The present disclosure provides a window glass for a vehicle to which the above-described window antenna for a vehicle is attached.

[0010] The present disclosure provides an antenna system for a vehicle including a plurality of window antennas spaced apart from each other, each of the plurality of window antennas being the window antenna for a vehicle described above. Advantageous effects of the invention

[0011] According to the technique of the present disclosure, there can be provided a glass antenna for a vehicle, a window glass for a vehicle, and an antenna system for a vehicle that can receive electromagnetic waves in multiple bands regardless of whether a member is folded back or folded back. Short description of the drawing Fig. 1 is a drawing figure showing a configuration example of a window antenna for a vehicle according to a first embodiment. Fig. 2 is a drawing figure showing a configuration example of a window antenna for a vehicle according to a second embodiment. Fig. 3 is a drawing figure showing a configuration example of a window antenna for a vehicle according to a third embodiment. Fig.4 is a drawing figure showing a configuration example of a window antenna for a vehicle according to a fourth embodiment. Fig. 5 is a drawing figure showing a configuration example of a window antenna for a vehicle according to a fifth embodiment. Fig. 6 is a drawing figure showing a configuration example of an antenna system for a vehicle according to an embodiment. Detailed description of the preferred embodiments

[0012] Embodiments according to the present disclosure will be described below with reference to the drawings. In each embodiment, deviations of directions such as a parallel direction, a perpendicular direction, a horizontal direction, and a vertical direction are tolerated to the extent that they do not impair the effects of the present invention. In addition, an X-axis direction, a Y-axis direction, and a Z-axis direction represent a direction parallel to the X-axis, a direction parallel to the Y-axis, and a direction parallel to the Z-axis, respectively. The X-axis direction, the Y-axis direction, and the Z-axis direction are perpendicular to each other.An XY plane, a YZ plane, and a ZX plane represent an imaginary plane parallel to the X-axis direction and the Y-axis direction, an imaginary plane parallel to the Y-axis direction and the Z-axis direction, and an imaginary plane parallel to the Z-axis direction and the X-axis direction, respectively.

[0013] Fig. 1 is a drawing figure showing a configuration example of a glass antenna for a vehicle according to a first embodiment. Fig. 1 shows a plan view of a part of a window glass 1 with a window antenna 101 attached thereto. The window antenna 101 is an example of a window antenna for a vehicle, and the window glass 1 is an example of a window pane for a vehicle.

[0014] The window pane 1 is attached to a window frame 2 of a vehicle body. The window frame 2 is a part of a conductive metal body that can be used for grounding and is also referred to as a flange. The window pane 1 can be, for example, a rear window pane attached to a window frame 2 at a rear part of a vehicle body, or a windshield pane attached to a window frame 2 at a front part of a vehicle body. In a case where the window pane 1 is a rear window pane or a windshield pane, the vertical direction (Y-axis direction) in Fig.1 corresponds to the vertical direction of the vehicle. The horizontal direction (X-axis direction) corresponds to the width direction of the vehicle. The window pane 1 is not limited to a rear window or a windshield and can also be, for example, a side window attached to a window frame 2 on one side of the vehicle.

[0015] The window antenna 101 is provided on the window pane 1 and is configured to receive vertically polarized electromagnetic waves in a first frequency band and horizontally polarized electromagnetic waves in a second frequency band.

[0016] The shape of the disc antenna 101 is suitable for transmitting and receiving electromagnetic waves in the VHF (Very High Frequency) band with a frequency of 30 MHz to 300 MHz and in the UHF (Ultra High Frequency) band with a frequency of 300 MHz to 3 GHz. The electromagnetic waves in the VHF band include electromagnetic waves in Band III (174 MHz to 240 MHz) of the DAB standard. The electromagnetic waves in Band III of the DAB standard are vertically polarized. The frequency band in Band III of the DAB standard is an example of a first frequency band. The electromagnetic waves in the UHF band include broadcast waves of digital terrestrial television from 470 MHz to 720 MHz. The broadcast waves of digital terrestrial television are horizontally polarized. The frequency band for the broadcast waves of digital terrestrial television is an example of a second frequency band.The disc antenna 101 resonates both in a frequency band in the VHF band (in particular band III of the DAB standard) and in a frequency band in the UHF band (in particular the band for the broadcast waves of digital terrestrial television).

[0017] The disc antenna 101 includes a feed electrode 3, a ground electrode 4, a first element 10, a second element 20, and a ground element 60.

[0018] The supply electrode 3 and the ground electrode 4 are arranged along a frame edge 2a on an upper side of the window frame 2 so that they are positioned away from each other. For example, the supply electrode 3 and the ground electrode 4 are provided along a glass edge 1a on the upper side of the window glass 1 so that they are located along the frame edge 2a when the window glass 1 is attached to the window frame 2. The frame edge 2a and the glass edge 1a extend in the X-axis direction in plan view, but may be curved or bent to an extent that does not impair the effects of the present invention.

[0019] The supply electrode 3 is a first electrode for supplying power and is known as a "hot-side" supply section, which is electrically connected to a signal line via a first conductive element (not shown). The supply electrode 3 is connected, for example, to a tuner via the first conductive element. An amplifier that amplifies the signal can be arranged between the supply electrode 3 and the tuner.

[0020] The grounding electrode 4 is a second electrode for grounding and is known as a "ground-side" lead section, which is grounded via a second conductive member (not shown). The grounding electrode 4 is connected, for example, to a metal body of the vehicle (e.g., the window frame 2 and the like) via the second conductive member.

[0021] The first element 10 is a conductor pattern extending from the feed electrode 3 in a direction away from the frame edge 2a or extending from the feed electrode 3 in a direction toward the frame edge 2a. As shown in Fig. 1, for example, one end of the first element 10 is connected to the supply electrode 3, the first element 10 extending in the direction away from the frame edge 2a, while the other end of the first element 10 is connected to the second element 20. The first element 10 is, for example, a line-shaped element that extends linearly from the supply electrode 3 toward a negative side in the Y-axis direction to a distal end portion 11, which is an end portion of the extension of the first element 10 toward the negative side in the Y-axis direction. An element length A of the first element 10 is a length from the supply electrode 3 to the distal end portion 11.

[0022] The direction in which the first element 10 extends from the feed electrode 3 can be either a direction away from the frame edge 2a (negative side in the Y-axis direction) or a direction toward the frame edge 2a (positive side in the Y-axis direction). This also applies to other embodiments. The first element 10 is preferably a conductor pattern of the former case, that is, a conductor pattern extending from the feed electrode 3 in the direction away from the frame edge 2a, because, compared to a conductor pattern of the latter case, the conductor pattern of the former case can have a longer distance between the second element 20 and the frame edge 2a, thereby easily preventing a reduction in antenna gain due to a metal body in the vicinity of the first element 10.Furthermore, the conductor pattern of the former case is preferable because the glass antenna 101 can be arranged close to the frame edge 2a while increasing the distance between the second element 20 and the frame edge 2a, so that the glass antenna 101 is less conspicuous in the window pane 1 (in particular, the glass antenna 101 does not reduce the view through the window pane 1).

[0023] The distance between the second member 20 and the frame edge 2a may be 1 mm or more, and preferably 10 mm or more. If the distance between the two is longer than necessary, the glass antenna 101 in the window glass 1 will be conspicuous. Therefore, the distance between the two may be 140 mm or less, and preferably 80 mm or less. Hereinafter, the first member 10 will be described as a conductor pattern extending from the feed electrode 3 in the direction away from the frame edge 2a. Also, since the flange and the glass antenna 101 are spaced apart by a certain distance in the Z-axis direction, the distance between the two when viewed in the Z-axis direction may be 3 mm or more, and preferably 10 mm or more. Since the shortest distance between the metal flange and the glass antenna 101 is configured to be a certain value or more, the antenna gain can be prevented from decreasing.

[0024] The second element 20 is a conductor pattern extending from the first element 10 along the frame edge 2a in a direction away from the ground electrode 4. One end of the second element 20 is connected to a distal end portion 11 of the first element 10, while a distal end portion 21 at the other end of the second element 20 is an open end. The second element 20 is, for example, a line-shaped element extending linearly from the distal end portion 11 toward a negative side in the X-axis direction to a distal end portion 21, which is an end portion of the extension of the second element 20 toward the negative side in the X-axis direction. An element length B of the second element 20 is a length from a connection point between one end of the second element 20 and the first element 10 (distal end portion 11 in the case shown in Fig. 1) to the distal end portion 21.

[0025] The grounding member 60 is a conductor pattern extending from the grounding electrode 4 along the frame edge 2a in a direction away from the feed electrode 3. One end of the grounding member 60 is connected to the grounding electrode 4, for example, while a distal end portion 61 at the other end of the grounding member 60 is an open end. The grounding member 60 is a linear member extending linearly from the grounding electrode 4 toward a positive side in the X-axis direction to a distal end portion 61, which is an end portion of the positive-side extension of the grounding member 60 in the X-axis direction. An element length E of the grounding member 60 is a length from the grounding electrode 4 to the distal end portion 61.

[0026] According to the window antenna 101 having the above-described configuration, the direction in which the first element 10 extends can be closer to a direction perpendicular to the horizontal plane (vertical direction), thus improving the reception sensitivity (antenna gain) when receiving vertically polarized electromagnetic waves, for example, in Band III of the DAB standard and the like. In addition, the direction in which the second element 20 and the grounding element 60 extend can be closer to a direction parallel to the horizontal plane (horizontal direction), thus improving the reception sensitivity (antenna gain) when receiving horizontally polarized electromagnetic waves, for example, in the broadcast waves of digital terrestrial television and the like. Therefore, the window antenna 101 as shown in Fig.1, vertically polarized electromagnetic waves in the first frequency band and horizontally polarized electromagnetic waves in the second frequency band are received even if the element is not folded back or bent back.

[0027] Note that even if at least one of the distal end portion 21 and the distal end portion 61 is a bent or folded-back open end, the disk antenna 101 can receive vertically polarized electromagnetic waves in the first frequency band and horizontally polarized electromagnetic waves in the second frequency band. This also applies to other embodiments. Fig.For example, in the aspect illustrated in FIG. 1, a bend in the Y-axis direction may be present in at least one of the distal end portion 21 and the distal end portion 61. Both the distal end portion 21 and the distal end portion 61 are preferably each an open end terminating in the extending direction of each of the linearly extending elements. This is because a simpler configuration of the elements without a folded-back portion and the like can contribute to preventing a reduction in performance due to interaction between the metal body of the vehicle and the antenna and improving the design.

[0028] Furthermore, since vertically polarized electromagnetic waves can be received in the first frequency band and horizontally polarized electromagnetic waves can be received in the second frequency band, the number of types (e.g., the number of items) of window antennas can be reduced. For example, a window glass 1 of the same type can be used regardless of whether vehicles equipped with the window glass 1 with the window antenna 101 attached thereto are delivered to a region where a broadcast service using vertically polarized electromagnetic waves is provided, such as Band III of the DAB standard and the like, or to a region where a broadcast service using horizontally polarized electromagnetic waves is provided, such as broadcast waves of digital terrestrial television and the like.

[0029] In the window antenna 101, the length of the first element 10 is shorter than the length of the second element 20. A longer length of the first element 10 has the advantage of improving the antenna gain for vertical polarization. Although the length of the first element 10 is shorter than the length of the second element 20 in the window antenna 101, the antenna gains can still be ensured for both vertically polarized electromagnetic waves in the first frequency band and horizontally polarized electromagnetic waves in the second frequency band. Furthermore, a reduction in size in the Y-axis direction (low profile) can be realized. Since the window antenna 101 is designed as a low-profile antenna, the window antenna 101 does not significantly obstruct the view through the window pane 1.

[0030] If the feed electrode 3 is connected to a signal line of a tuner via the first conductive element, the disc antenna 101 can receive vertically polarized electromagnetic waves in the first frequency band even if no wire is connected to the ground electrode 4 (that is, even if the second conductive element is not connected to the ground electrode 4). In other words, if vertically polarized electromagnetic waves in the first frequency band are to be received, the disc antenna 101 can be used as a monopole antenna. Alternatively, if the feed electrode 3 is connected to a signal line of a tuner via the first conductive element and the ground electrode 4 is grounded via the second conductive element, the disc antenna 101 can receive horizontally polarized electromagnetic waves in the second frequency band.In other words, in a case where horizontally polarized electromagnetic waves in the second frequency band are to be received, the disk antenna 101 can be used as a dipole antenna.

[0031] The second element 20 is not limited to extending from the distal end portion 11 of the first element 10. Alternatively, the second element 20 may also extend from a portion near the distal end portion 11.

[0032] The element length E of the grounding element 60 is preferably 5 mm or more and 160 mm or less, and more preferably 30 mm or more and 100 mm or less, in order to improve the antenna gain for horizontally polarized electromagnetic waves in the second frequency band.

[0033] Fig. 2 is a drawing figure showing a configuration example of a window antenna for a vehicle according to a second embodiment. Fig. 2 is a plan view of a portion of a window pane 1 with a glass antenna 102 attached thereto. The glass antenna 102 is an example of a glass antenna for a vehicle. Explanations regarding the same configurations and effects as those in the above-described embodiment are omitted or simplified by referring to the above explanations.

[0034] The disc antenna 102 differs from the disc antenna 101 in that the disc antenna 102 additionally includes a third element 30 compared to the disc antenna 101.

[0035] The third element 30 is a conductor pattern electrically connected to the feed electrode 3 and extending along the frame edge 2a in the direction away from the ground electrode 4. The third element 30 extends from an intermediate portion 12 of the first element 10, and the length of the third element 30 is shorter than the length of the second element 20. For example, one end of the third element 30 is connected to the intermediate portion 12 of the first element 10, while a distal end portion 31 at the other end of the third element 30 is an open end. The third element 30 is a line-shaped element that extends linearly from the intermediate portion 12 toward a negative side in the X-axis direction to the distal end portion 31, which is an end portion of the extension of the third element 30 toward the negative side in the X-axis direction.An element length D of the third element 30 is a length from a connection point between one end of the third element 30 and the first element 10 (i.e. intermediate section 12 in the case of the third element 30 shown in . Fig. 2) to the distal end portion 31. If the element length A of the first element 10 is defined as 1, the intermediate portion 12 of the first element 10 is located, for example, at a position away from the distal end portion 11 at a distance of 0.05 to 0.95.

[0036] According to the disc antenna 102 having the above-described configuration, the directions in which the second element 20, the third element 30, and the grounding element 60 extend can be brought closer to a direction parallel to the horizontal plane (i.e., horizontal direction), and therefore the reception sensitivity (antenna gain) when receiving horizontally polarized electromagnetic waves, such as broadcast waves of digital terrestrial television and the like, is improved. Therefore, the disc antenna 102, as shown in Fig. 2, vertically polarized electromagnetic waves in the first frequency band and horizontally polarized electromagnetic waves in the second frequency band are received even if the element is not folded back or bent back.

[0037] Note that even if the distal end portion 31 is a bent or folded-back open end, the disk antenna 102 can receive vertically polarized electromagnetic waves in the first frequency band and horizontally polarized electromagnetic waves in the second frequency band. This also applies to other embodiments. Fig.For example, in the aspect illustrated in Figure 2, a bend in the Y-axis direction may be present in the distal end portion 31. The distal end portion 31 is preferably an open end that terminates in the extending direction of the linearly extending third element 30. This is because a simpler configuration of the elements without a folded-back portion and the like can contribute to preventing performance degradation due to interaction between the metal body of the vehicle and the antenna and to improving the design.

[0038] In the Fig.2, the shortest distance G between the second element 20 and the third element 30 is preferably 5 mm or more, more preferably 15 mm or more, and even more preferably 25 mm or more. Since the shortest distance G is set to this length, the antenna gains for both vertically polarized electromagnetic waves in the first frequency band and horizontally polarized electromagnetic waves in the second frequency band improve. Note that the shortest distance G is preferably 100 mm or less, and particularly preferably 65 mm or less, thereby preventing the window antenna 102 from significantly obstructing the view through the window pane 1.

[0039] In the Fig.2, the first total length (A+B) between the feeding electrode 3 and the distal end portion 21 of the second element 20 is different from a second total length (C+D) between the feeding electrode 3 and the distal end portion 31 of the third element 30. Therefore, the first total length (A+B) may be configured as a length suitable for receiving vertically polarized electromagnetic waves in the first frequency band, while the second total length (C+D) may be configured as a length suitable for receiving horizontally polarized electromagnetic waves in the second frequency band, which is different from the first frequency band.

[0040] In the Fig.2, the first total length (A+B) is longer than the second total length (C+D), and the shortest distance between the second element 20 and the frame edge 2a (hereinafter also referred to as distance BF) is longer than the shortest distance between the third element 30 and the frame edge 2a (hereinafter also referred to as distance DF). Therefore, the first total length (A+B) can be configured as a length suitable for receiving vertically polarized electromagnetic waves in the first frequency band, while the second total length (C+D) can be configured as a length suitable for receiving horizontally polarized electromagnetic waves in the second frequency band higher than the first frequency band.In a case where the first element 10 extends from the feed electrode 3 in the direction away from the frame edge 2a, the second element 20 can be kept farther away from the frame edge 2a than the third element 30 because the distance BF is longer than the distance DF. Therefore, the second element 20 and the frame edge 2a are kept apart from each other with extension in the horizontal direction, so that a reduction in antenna performance for vertically polarized electromagnetic waves in the first frequency band can be prevented.

[0041] As with the Fig.2, the first element 10 extends from the feed electrode 3 in the direction away from the frame edge 2a, and the distance DF may be 1 mm or more, and more preferably 10 mm or more. If the distance BF is longer than necessary, the glass antenna 102 becomes conspicuous in the windowpane 1. Therefore, the distance BF may be 140 mm or less, and preferably 80 mm or less. In a case where the first element 10 extends from the feed electrode 3 in a direction toward the frame edge 2a, the glass antenna 102 is in a symmetrical pattern (not shown) with respect to an imaginary line parallel to the X-axis passing through the center of the feed electrode 3 and the center of the ground electrode 4.In a case where the glass antenna 102 is configured in this pattern (not shown), the second element 20 comes closest to the flange, and accordingly, the distance BF may be 1 mm or more, and preferably 10 mm or more. If the distance between the glass antenna 102 and the flange is longer than necessary, the glass antenna 102 will become conspicuous in the window glass 1. Therefore, in the glass antenna 102 having this pattern (not shown), the distance DF may be 140 mm or less, and preferably 80 mm or less. Since the flange and the glass antenna 102 are also spaced apart by a certain distance in the Z-axis direction, the distance between the two when viewed in the Z-axis direction may be 3 mm or more, and preferably 10 mm or more.Since the shortest distance between the metal flange and the glass antenna 102 is configured as a certain value or more, a reduction in antenna performance can be prevented.

[0042] The first total length (A+B) between the supply electrode 3 and the distal end portion 21 of the second element 20 is L V the central wavelength of the first frequency band is denoted by λ V and the wavelength shortening rate of the window pane 1 is denoted by k (for example, 0.64). To improve the antenna gain in the first frequency band, it is preferable if the following expression v1 is satisfied. 0.13×λv×k≤Lv≤0.33×λv×k

[0043] It is more preferred if the following expression v2 is satisfied. 0.17×λv×k≤Lv≤0.29×λv×k

[0044] For example, if the first frequency band is in Band III of the DAB standard, LV preferably 130 mm or more and 300 mm or less, and more preferably 160 mm or more and 270 mm or less, in order to improve the antenna gain in Band III.

[0045] The second total length (C+D) between the supply electrode 3 and the distal end portion 31 of the third element 30 is L H the central wavelength of the second frequency band is denoted by λ H and the wavelength shortening rate of the window pane 1 is denoted by k. In order to improve the antenna gain in the second frequency band, it is preferred if the following expression h1 is satisfied 0.16×λH×k≤LH≤0.60×λH×k

[0046] It is more preferred if the following expression h2 is satisfied 0.23×λH×k≤LH≤0.47×λH×k

[0047] For example, if the second frequency band is in a band of broadcast waves of digital terrestrial television, then L H preferably 50 mm or more and 180 mm or less, and more preferably 70 mm or more and 140 mm or less, in order to improve the antenna gain.

[0048] Fig. 3 is a drawing figure showing a configuration example of a window antenna for a vehicle according to a third embodiment. Fig. 3 is a plan view of a portion of a window pane 1 with a glass antenna 103 attached thereto. The glass antenna 103 is an example of a glass antenna for a vehicle. Explanations regarding the same configurations and effects as those in the previously described embodiments are omitted or simplified by referring to the above explanations.

[0049] The disc antenna 103 differs from the disc antenna 101 in that the disc antenna 103 additionally includes a third element 30 and a fourth element 40 compared to the disc antenna 101.

[0050] The third element 30 is a conductor pattern electrically connected to the feed electrode 3 and extending along the frame edge 2a in the direction away from the ground electrode 4. The third element 30 extends from the fourth element 40, and the length of the third element 30 is longer than the length of the fourth element 40. For example, one end of the third element 30 is connected to the distal end portion 41 of the fourth element 40, while a distal end portion 31 at the other end of the third element 30 is an open end. The third element 30 is, for example, a line-shaped element that extends linearly from the distal end portion 41 toward a negative side in the X-axis direction to a distal end portion 31, which is an end portion of the extension of the third element 30 toward the negative side in the X-axis direction.An element length D of the third element 30 is a length from a connection point between one end of the third element 30 and the fourth element 40 (i.e. distal end portion 41 in the case shown in . Fig. 3) to the distal end portion 31.

[0051] The fourth element 40 is a conductor pattern extending from the feed electrode 3 in a direction away from the frame edge 2a or extending from the feed electrode 3 in a direction toward the frame edge 2a. As shown in Fig.3, for example, one end of the fourth element 40 is connected to the supply electrode 3 and extends in the direction away from the frame edge 2a, while the other end of the fourth element 40 is connected to one end of the third element 30. The fourth element 40 is, for example, a line-shaped element that extends linearly from the supply electrode 3 toward a negative side in the Y-axis direction to a distal end portion 41, which is an end portion of the extension of the fourth element 40 toward the negative side in the Y-axis direction. The element length C of the fourth element 40 is the length from the supply electrode 3 to the distal end portion 41.

[0052] The direction in which the fourth element 40 extends from the feed electrode 3 can be either the direction away from the frame edge 2a (i.e., the negative side in the Y-axis direction) or a direction toward the frame edge 2a (positive side in the Y-axis direction). This also applies to other embodiments. The fourth element 40 is preferably a conductor pattern of the former case, that is, a conductor pattern extending from the feed electrode 3 in the direction away from the frame edge 2a, because, compared to a conductor pattern of the latter case, the conductor pattern of the former case can have a longer distance between the third element 30 and the frame edge 2a, thereby easily preventing a reduction in antenna gain caused by a metal body in the vicinity of the fourth element 40.Furthermore, the conductor pattern of the former case is preferable because the window antenna 103 can be arranged near the frame edge 2a while increasing the distance between the third element 30 and the frame edge 2a, so that the window antenna 103 becomes less conspicuous in the window pane 1 (in particular, the window antenna 103 does not significantly reduce the view through the window pane 1).

[0053] The distance between the third member 30 and the frame edge 2a may be 1 mm or more, and preferably 10 mm or more. If the distance between the two is longer than necessary, the glass antenna 103 in the window glass 1 will be conspicuous. Therefore, the distance between the two may be 140 mm or less, and preferably 80 mm or less. Hereinafter, the third member 30 will be described as a conductor pattern extending on the side opposite to the frame edge 2a from the feed electrode 3. Since the flange and the glass antenna 103 are also located a certain distance apart in the Z-axis direction, the distance between the two when viewed in the Z-axis direction may be 3 mm or more, and preferably 10 mm or more. Since the shortest distance between the metal flange and the glass antenna 103 is configured to be a certain value or more, a reduction in antenna gain can be prevented.

[0054] According to the window antenna 103 having the above-described configuration, the direction in which the second element 20, the third element 30, and the grounding element 60 extend can be made closer to a direction parallel to the horizontal plane (i.e., horizontal direction), and therefore the reception sensitivity (antenna gain) when receiving horizontally polarized electromagnetic waves, for example, broadcast waves of digital terrestrial television and the like, is improved. As shown in Fig. 3, the window antenna 103 can therefore receive vertically polarized electromagnetic waves in the first frequency band and horizontally polarized electromagnetic waves in the second frequency band even if the element is not folded back or bent back.

[0055] Fig.4 is a drawing figure showing a configuration example of a window antenna for a vehicle according to a fourth embodiment. Fig. 4 is a plan view of a portion of a window pane 1 with a glass antenna 104 attached thereto. The glass antenna 104 is an example of a glass antenna for a vehicle. Explanations regarding the same configurations and effects as those in the above-described embodiments are omitted or simplified by referring to the above-described explanations.

[0056] The disc antenna 104 differs from the disc antenna 103 in that the disc antenna 104 additionally has a fifth element 50 compared to the disc antenna 103.

[0057] The fifth element 50 is a conductor pattern extending between the second element 20 and the third element 30 from the intermediate portion 13 of the first element 10 in the direction away from the ground electrode 4. One end of the fifth element 50 is connected, for example, to the intermediate portion 13 of the first element 10, while a distal end portion 51 at the other end of the fifth element 50 is an open end. The fifth element 50 is, for example, a line-shaped element extending linearly from the intermediate portion 13 toward a negative side in the X-axis direction and extending parallel to the second element 20 to the distal end portion 51, which is an end portion of the negative-side extension of the fifth element 50 in the X-axis direction.An element length F of the fifth element 50 is a length from a connection point between one end of the fifth element 50 and the first element 10 (i.e., the intermediate portion 13 in the case shown in . Fig. 4) to the distal end portion 51. An element not shown may be present and establish a connection between the distal end portion 21 or a portion near the distal end portion 21 and the distal end portion 51 or a portion near the distal end portion 51.

[0058] The disc antenna 104 of the Fig. 4, the fifth element 50 is connected to the window antenna 103, which in Fig. 3; however, in one aspect, the fifth element 50 may also be added to the window antenna 102 shown in Fig. 2 shown, may be added.

[0059] According to the window antenna 104 having the above-described configuration, the direction in which the second element 20, the third element 30, the fifth element 50, and the grounding element 60 extend can be made closer to a direction parallel to the horizontal plane (i.e., horizontal direction), and therefore the reception sensitivity (antenna gain) when receiving horizontally polarized electromagnetic waves, for example, broadcast waves of digital terrestrial television and the like, is improved. Therefore, as shown in Fig. 4, the disc antenna 104 can receive vertically polarized electromagnetic waves in the first frequency band and horizontally polarized electromagnetic waves in the second frequency band even if the element is not folded back or bent back.

[0060] Note that even if the distal end portion 51 is a bent or folded-back open end, the disk antenna 104 can receive vertically polarized electromagnetic waves in the first frequency band and horizontally polarized electromagnetic waves in the second frequency band. This also applies to other embodiments. Fig.For example, in the aspect illustrated in Figure 4, a bend in the Y-axis direction may be present in the distal end portion 51. The distal end portion 51 is preferably an open end that terminates in the extending direction of the linearly extending fifth element 50. This is because a simpler configuration of the elements without a folded-back portion and the like can contribute to preventing performance degradation due to interaction between the metal body of the vehicle and the antenna and to improving the design.

[0061] Fig. 5 is a drawing figure showing a configuration example of a window antenna for a vehicle according to a fifth embodiment. Fig.5 is a plan view of a portion of the window pane 1 with a glass antenna 105 attached thereto. The glass antenna 105 is an example of a glass antenna for a vehicle. Explanations regarding the same configurations and effects as those in the above-described embodiments are omitted or simplified by referring to the above-described explanations.

[0062] The disc antenna 105 is different from the disc antenna 103 in that the disc antenna 105 does not include the ground electrode 4 and the grounding element 60 compared to the disc antenna 103.

[0063] According to the window antenna 105 having the above-described configuration, the direction in which the second element 20 and the third element 30 extend can be made closer to a direction parallel to the horizontal plane (i.e., horizontal direction), and therefore the reception sensitivity (antenna gain) when receiving horizontally polarized electromagnetic waves, for example, broadcast waves of digital terrestrial television and the like, is improved. Therefore, as shown in Fig. 5, the disc antenna 105 can receive vertically polarized electromagnetic waves in the first frequency band and horizontally polarized electromagnetic waves in the second frequency band even if the element is not folded back or bent back.

[0064] Furthermore, since the feed electrode 3 is connected to a signal line of a tuner via the first conductive member, the disc antenna 105 can receive vertically polarized electromagnetic waves in the first frequency band and horizontally polarized electromagnetic waves in the second frequency band without the ground electrode 4 and the ground member 60. In other words, when vertically polarized electromagnetic waves in the first frequency band are to be received, the disc antenna 105 can be used as a monopole antenna.

[0065] Fig. 6 is a drawing figure showing a configuration example of an antenna system for a vehicle according to an embodiment. Fig. The antenna system 100 shown in Figure 6 is an example of an antenna system for a vehicle that includes multiple window antennas spaced apart from each other. Fig.6, the plurality of glass antennas arranged remotely from each other are, for example, the glass antennas 103A, 103B, which have a configuration similar to that of the above-described glass antenna 103. The glass antennas arranged remotely from each other on the window pane 1 may be glass antennas according to other embodiments.

[0066] In this way, a two-channel diversity antenna can be formed by disposing two disk antennas away from each other according to this embodiment. Additionally, a four-channel diversity antenna can be formed by disposing four disk antennas away from each other according to this embodiment.

[0067] Next, shown in Tables 1 to 10 are measurement results of antenna gains in the bands of both Band III of the DAB standard and broadcast waves of digital terrestrial television for window antennas mounted on a window surface of a real vehicle's rear window.

[0068] Please note that "DAB gain" indicates an average value of antenna gains (in dBd) measured every 3 MHz for vertically polarized electromagnetic waves in a frequency band (from 174 MHz to 240 MHz) in Band III of the DAB standard. "DTV gain" indicates an average value of antenna gains (in dBd) measured every 18 MHz for horizontally polarized electromagnetic waves in a frequency band (from 473 MHz to 713 MHz) of digital terrestrial television broadcast waves. [Table 1] A B A+B DAB amplification DTV amplification a1 40 mm 170 mm 210 mm 7,1 4,3 a2 35 mm 175 mm 210 mm 6,9 3,6 a3 30 mm 180 mm 210 mm 6,8 2,9 a4 25 mm 185 mm 210 mm 6,5 2,7 a5 20 mm 190 mm 210 mm 6,4 1,6 a6 15 mm 195 mm 210 mm 5,9 0,7

[0069] Table 1 shows a characteristic of the antenna gain of the disc antenna 103 as a function of a change in the ratio between the element length A of the first element 10 and the element length B of the second element 20, while as in the Fig. 3, the first total length (A+B) is fixed at 210 mm. The other element lengths and spacings were fixed at C = 10 mm, D = 90 mm, E = 50 mm, and the spacing DF = 34 mm. The second element 20 and the third element 30 were arranged in parallel, with the shortest distance G between the two elements being adjusted within a range of 5 mm to 35 mm. In this case, the spacing BF was within a range of 39 mm to 69 mm.

[0070] Even when the element length A was shortened to reduce the height, both the DAB and DTV gains achieved gains of 0 dBd or more, which is sufficient for reception of both electromagnetic waves. When the element length A was 40 mm and the element length B was 170 mm, both the DAB and DTV gains reached their maximum antenna gains. [Table 2] C D C+D DAB amplification DTV amplification b7 0 mm 100 mm 100 mm 7,3 4,2 b1 10 mm 90 mm 100 mm 7,1 4,3 b2 15 mm 85 mm 100 mm 7,3 4,0 b3 20 mm 80 mm 100 mm 7,2 3,9 b4 25 mm 75 mm 100 mm 7,3 3,6 b5 30 mm 70 mm 100 mm 7,2 3,4 b6 35 mm 65 mm 100 mm 7,2 2,4

[0071] Table 2 shows a characteristic of the antenna gain of the disc antenna 103 as a function of a change in the ratio between the element length D of the third element 30 and the element length C of the fourth element 40, while in the Fig.3, the second total length (C+D) was fixed at 100 mm. The other element lengths and spacings were fixed at A = 40 mm, B = 170 mm, E = 50 mm, and the spacing BF = 64 mm. The second element 20 and the third element 30 were arranged in parallel, with the shortest distance G between the two elements being adjusted within a range of 5 mm to 35 mm. In this case, the spacing DF was within a range of 29 mm to 59 mm.

[0072] The more the element length D of the third element 30 increased in the horizontal direction, the more the DTV gain improved while the DAB gain was ensured. [Table 3] A+B C+D G DAB amplification DTV amplification c7 210 mm 100 mm 40 mm 7,3 4,2 c1 210 mm 100 mm 30 mm 7,1 4,3 c2 210 mm 100 mm 25 mm 7,3 4,0 c3 210 mm 100 mm 20 mm 7,2 3,9 c4 210 mm 100 mm 15 mm 7,3 3,6 c5 210 mm 100 mm 10 mm 7,2 3,4 c6 210 mm 100 mm 5 mm 7,2 2,4

[0073] Table 3 shows a characteristic of the antenna gain of the disc antenna 103 with a reduction of the shortest distance G corresponding to an increase of the element length C, while in the Fig.In the aspect shown in Figure 3, the first total length (A+B) was fixed at 210 mm, the second total length (C+D) was fixed at 100 mm, and the distance BF was fixed at 64 mm. In this case, the element length E was fixed at 50 mm. In this case, the distance DF was in a range from 24 mm to 59 mm.

[0074] When the shortest distance G was decreased by increasing the element length C, the DAB gain did not decrease significantly because the element length A was fixed. The DTV gain improved as the shortest distance G increased. In other words, the longer the shortest distance G, the more the DAB gain and the DTV gain improved. [Table 4] A+B C+D G DAB amplification DTV amplification d1 210 mm 100 mm 30 mm 7,1 4,3 d2 210 mm 100 mm 25 mm 6,9 3,6 d3 210 mm 100 mm 20 mm 6,8 2,9 d4 210 mm 100 mm 15 mm 6,5 2,7 d5 210 mm 100 mm 10 mm 6,4 1,6 d6 210 mm 100 mm 5 mm 5,9 0,7

[0075] Table 4 shows a characteristic of the antenna gain of the disc antenna 103 with a reduction of the shortest distance G corresponding to an increase of the element length A, while in the Fig.In the aspect shown in Figure 3, the first total length (A+B) was fixed at 210 mm, the second total length (C+D) was fixed at 100 mm, and the distance DF was fixed at 34 mm. In this case, the element length E was fixed at 50 mm. In this case, the distance BF was in a range from 39 mm to 64 mm.

[0076] When the shortest distance G was reduced by decreasing the element length A, the DAB gain decreased due to the decrease in the element length A. As the shortest distance G decreased, the DTV gain also decreased. In other words, the longer the shortest distance G, the more the DAB gain and the DTV gain improved. [Table 5] E DAB amplification DTV amplification e1 70 mm 7,0 3,8 e2 60 mm 7,0 4,1 e3 50 mm 7,1 4,3 e4 40 mm 7,1 4,1 e5 30 mm 7,1 3,4 e6 20 mm 7,1 2,8 e7 10 mm 7,1 2,6 e8 0 mm 7,1 2,8

[0077] Table 5 shows a characteristic of the antenna gain of the disc antenna 103 as a function of a change in the element length E for the Fig.3. The other element lengths and distances were fixed at A = 40 mm, B = 170 mm, C = 10 mm, D = 90 mm, G = 30 mm, distance BF = 64 mm and distance DF = 34 mm. In Table 5, the case where the element length E is 0 mm corresponds to a Fig. 5 presented aspect.

[0078] Even in a case where the element length E is 0 mm, both the DAB gain and the DTV gain could achieve a gain of 0 dBd or more, which is sufficient for the reception of both electromagnetic waves. [Table 6] B A+B DAB amplification DTV amplification f1 250 mm 290 mm 5,8 0,7 f2 230 mm 270 mm 6,1 1,0 f3 210 mm 250 mm 7,8 1,6 f4 190 mm 230 mm 7,8 2,9 f5 170 mm 210 mm 7,1 4,3 f6 150 mm 190 mm 5,7 5,2 f7 130 mm 170 mm 3,8 5,2 f8 110 mm 150 mm 2,3 4,6 f9 90 mm 130 mm 0,9 4,1 f10 70 mm 110 mm 0,2 3,6 f11 50 mm 90 mm -0,9 3,1 f12 30 mm 70 mm -1,3 3,2 f13 0 mm 40 mm -2,6 2,6

[0079] Table 6 shows a characteristic of the antenna gain of the disc antenna 103 as a function of a change in the element length B, while in the Fig. 3, the element length A was fixed at 40 mm. The other element lengths and spacings were fixed at C = 10 mm, D = 90 mm, G = 30 mm, spacing BF = 64 mm, spacing DF = 34 mm, and E = 50 mm. The longer the element length B, the more the DAB gain improved. [Tabelle 7] D C+D DAB-Verstärkung DTV-Verstärkung g1 140 mm 150 mm 6,9 4,0 g2 120 mm 130 mm 7,1 4,1 g3 100 mm 110 mm 7,1 4,7 g4 90 mm 100 mm 7,1 4,9 g5 80 mm 90 mm 7,1 4,3 g6 60 mm 70 mm 7,2 3,0 g7 40 mm 50 mm 7,2 0,5 g8 20 mm 30 mm 7,2 0,6 g9 0 mm 10 mm 7,2 2,2

[0080] Table 7 shows a characteristic of the antenna gain of the disc antenna 103 as a function of a change in the element length D, while in the Fig. 3, the element length C was fixed at 10 mm. The other element lengths and spacings were fixed at A = 40 mm, B = 170 mm, G = 30 mm, spacing BF = 64 mm, spacing DF = 34 mm, and E = 50 mm. As the element length D increases, the DTV gain improves proportionally. [Tabelle 8] F DAB-Verstärkung DTV-Verstärkung h1 250 mm 5,2 1,2 h2 230 mm 6,5 2,7 h3 210 mm 7,1 3,8 h4 190 mm 7,5 4,5 h5 170 mm 7,4 4,8 h6 150 mm 7,1 4,8 h7 130 mm 7,1 4,7 h8 110 mm 7,1 4,6 h9 90 mm 7,1 4,4 h10 70 mm 7,1 2,1 h11 50 mm 7,1 3,5 h12 30 mm 7,1 4,2 h13 0 mm 7,1 4,3

[0081] Table 8 shows a characteristic of the antenna gain of the disc antenna 104 as a function of a change in the element length F of the fifth element 50, which is parallel to the second element 20 and the third element 30, in which Fig. 4. The other element lengths and distances were fixed at A = 40 mm, B = 170 mm, C = 10 mm, D = 90 mm, G = 30 mm, the distance BF = 64 mm, the distance DF = 34 mm, and E = 50 mm. One end of the fifth element 50 was connected to the intermediate section 13 of the first element 10, while the distance between the feed electrode 3 and the intermediate section 13 was 10 mm. Since the fifth element 50 having the element length F was added, the properties improved compared to the Fig. 3, in which the fifth element 50 was omitted, both the DAB gain and the DTV gain decreased. However, when the element length F became too long relative to the element length B (about 210 mm or more, see Table 8), the DAB gain and the DTV gain began to decrease. [Tabelle 9] H DAB-Verstärkung DTV-Verstärkung i1 20 mm 7,1 4,3 i2 15 mm 7,0 4,4 i3 10 mm 7,1 4,2 i4 5 mm 7,0 4,2 i5 0 mm 7,2 3,4

[0082] Table 9 shows a characteristic of the antenna gain of the window antenna 103 as a function of a change in the separation distance H between the first element 10 and the fourth element 40 in the Fig. 3. The other element lengths and distances were fixed at A = 40 mm, B = 170 mm, C = 10 mm, D = 90 mm, G = 30 mm, distance BF = 64 mm, distance DF = 34 mm, and E = 50 mm. In Table 9, the case where H is 0 mm corresponds to the case shown in Fig. 2, assuming that one end of the third element 30 is connected to the intermediate portion 12 of the first element 10 and the distance between the feed electrode 3 and the intermediate portion 12 is 10 mm. For each of the above-described distances, both the DAB gain and the DTV gain could achieve a gain sufficient for reception of both electromagnetic waves. [Table 10] A B A+B DAB-Verstärkung DTV-Verstärkung 10 mm 240 mm 250 mm 5,5 -1,6 10 mm 220 mm 230 mm 5,6 -1,7 10 mm 210 mm 220 mm 5,7 -1,4 10 mm 200 mm 210 mm 5,13 -1,1 10 mm 180 mm 190 mm 4,1 -0,7 10 mm 130 mm 140 mm -0,7 0,5 10 mm 110 mm 120 mm -2,4 1,3 10 mm 100 mm 110 mm -3,4 2 10 mm 90 mm 100 mm -4,3 2,3 10 mm 80 mm 90 mm -5,5 2,8 10 mm 60 mm 70 mm -7,2 2,1 A B A+B DAB-Verstärkung DTV-Verstärkung 20 mm 240 mm 260 mm 5,8 -0,8 20 mm 220 mm 240 mm 6,2 -0,5 20 mm 210 mm 230 mm 5,9 -0,3 20 mm 200 mm 220 mm 6,2 0,1 20 mm 180 mm 200 mm 5 0,2 20 mm 130 mm 150 mm 0,9 0,5 20 mm 110 mm 130 mm -1,3 1,5 20 mm 100 mm 120 mm -1,9 1,6 20 mm 90 mm 110 mm -3,2 2,5 20 mm 80 mm 100 mm -3,9 2,4 20 mm 60 mm 80 mm -5,5 2,5 A B A+B DAB-Verstärkung DTV-Verstärkung 30 mm 240 mm 270 mm 6,4 0,2 30 mm 220 mm 250 mm 6,5 0,2 30 mm 210 mm 240 mm 7,2 0,6 30 mm 200 mm 230 mm 6,4 0,8 30 mm 180 mm 210 mm 6,5 1,2 30 mm 130 mm 160 mm 2,4 0,7 30 mm 110 mm 140 mm 0 1,2 30 mm 100 mm 130 mm -0,4 1,1 30 mm 90 mm 120 mm -1,8 1,9 30 mm 80 mm 110 mm -2,4 1,8 30 mm 60 mm 90 mm -4,5 2,6

[0083] Table 10 shows a characteristic of the antenna gain of the disc antenna 101 as a function of a change in the element length B, while in the Fig. In the aspect shown in Figure 1, the element length A was fixed at 10 mm, 20 mm, and 30 mm. In this case, the other element length and spacing were fixed at E = 50 mm and spacing BF = 64 mm.

[0084] In a case where the first total length (A+B) was within a preferred range (190 mm or more and 270 mm or less) in Band III of the DAB standard, sufficient DAB gain was ensured. In a case where the first total length (A+B) was within a preferred range (70 mm or more and 130 mm or less) of the digital terrestrial television broadcast waves, sufficient DTV gain was ensured. Furthermore, when A = 30 mm and B = 180 mm (with A+B = 210 mm), both the DAB gain and the DTV gain could achieve a gain sufficient for reception of both electromagnetic waves.

[0085] Although the glass antenna for a vehicle, the window glass for a vehicle, and the antenna system for a vehicle have been described above based on embodiments, the present invention is not limited to the above-described embodiments. Various modifications and improvements, such as combinations and replacements with a part or all of another embodiment, can be made within the scope of the present invention.

[0086] For example, an "end portion" of an antenna may be a starting or ending point of the element's extension, or a portion near the starting or ending point that is a conductor portion adjacent to the starting or ending point thereof. Furthermore, a connecting portion between conductors may be connected with a bend. An "end portion" of an element may be bent or folded back without giving up the effects of the present invention. An "end portion" may include "an end," "another end," "the further end," "a distal end portion," or "an open end" as described in the specification of the present application. Furthermore, a connecting portion between elements may be connected with a bend.

[0087] Antenna elements and electrodes are formed, for example, by printing and firing a paste containing a conductive metal (such as silver paste) on a vehicle-inside side surface of a window glass. However, the method of forming antenna elements and electrodes is not limited to this method. Antenna elements and electrodes can also be formed, for example, by providing a straight material or a sheet-like material containing a conductive substance such as copper on a vehicle-inside side surface or a vehicle-outside side surface of a window glass. Alternatively, antenna elements and electrodes can be attached to the window glass with an adhesive or the like, or provided inside the window glass.

[0088] With regard to assembly, the shape of the electrode is preferably rectangular or polygonal, for example, square, approximately square, rectangular, or approximately rectangular. Circular shapes, such as circular, approximately circular, elliptical, or approximately elliptical, can also be used.

[0089] It is also possible to employ a structure in which a conductive layer constituting at least one of an antenna element and an electrode is provided inside or on a surface of a resin film, the resin film having the conductive layer being applied to a vehicle-inside side surface or a vehicle-outside side surface of a window glass. It is also possible to employ a structure in which a flexible printed circuit board formed with at least one of an antenna element and an electrode is provided on a vehicle-inside side surface or a vehicle-outside side surface of a window glass.

[0090] As in Fig. 6, an electrode and an antenna element may be partially or entirely disposed on a light-shielding film 5 formed on a glass surface at the periphery of the window glass 1. A specific example of the light-shielding film 5 includes ceramics, such as a black ceramic film. When the window glass is viewed from the outside of the vehicle, a part of the window glass 1 on a glass edge side relative to a film edge 5a of the light-shielding film 5 is not visible from the outside of the vehicle, and a window glass with an excellent design is obtained.

[0091] The window antenna according to the present embodiment is not limited to the aspect in which it is arranged along the window edge 1a at the top of the window glass 1 (in other words, at the frame edge 2a at the top of the window frame 2) as shown in Fig. 6. The glass antenna according to the present embodiment may be provided, for example, along any one of the glass edge 1b on a lower side of the window glass 1 (i.e., a frame edge on a lower side of the window frame 2), the glass edge 1c on the left side of the window glass 1 (i.e., a frame edge on the left side of the window frame 2), and the glass edge 1d on the right side of the window glass 1 (i.e., a frame edge on the right side of the window frame 2).

[0092] Furthermore, at least one of the first element 10 and the fourth element 40 may extend from the feed electrode 3 in a direction toward a nearest frame edge (for example, the frame edge 2a in Fig. 1) extend.

[0093] The shape of a corner of an antenna element is not limited to a right angle, but can also be rounded in an arc.

Claims

[1] A window antenna (103, 104, 105) for a vehicle, which is provided on a window pane (1) attached to a window frame (2) of a vehicle body and can receive a vertically polarized electromagnetic wave in a first frequency band and a horizontally polarized electromagnetic wave in a second frequency band, the window antenna (103, 104, 105) for a vehicle comprising: a supply electrode (3) configured to supply power; a first element (10) extending from the supply electrode (3) in a direction toward a frame edge (2a) of the window frame (2) or in a direction away from the frame edge (2a); a second element (20) extending from the first element (10) along the frame edge (2a); a third element (30) extending along the second element (20); and a fourth element (40) extending from the supply electrode (3) in a direction towards the frame edge (2a) or in a direction away from the frame edge (2a), wherein a length of the first element (10) is shorter than a length of the second element (20), and the third element (30) extends from the fourth element (40), and a length of the third element (30) is longer than a length of the fourth element (40). [2] A window antenna (103, 104, 105) for a vehicle according to claim 1, wherein the first element (10) and the fourth element (40) extend from the feed electrode (3) in a direction away from the frame edge (2a). [3] A glass antenna (103, 104, 105) for a vehicle according to any one of claims 1 to 2, wherein a shortest distance between the second element (20) and the third element (30) is 5 mm or more. [4] A window antenna (103, 104, 105) for a vehicle according to any one of claims 1 to 3, wherein a first total length between the feed electrode (3) and a distal end portion (21) of the second element (20) is different from a second total length between the feed electrode (3) and a distal end portion (31) of the third element (30). [5] A window antenna (103, 104, 105) for a vehicle according to any one of claims 1 to 4, wherein a first total length between the feed electrode (3) and a distal end portion (21) of the second element (20) is longer than a second total length between the feed electrode (3) and a distal end portion (31) of the third element (30), and a first shortest distance between the second element (20) and the frame edge (2a) is longer than a second shortest distance between the third element (30) and the frame edge (2a). [6] A windshield antenna (104) for a vehicle according to any one of claims 1 to 5, further comprising: a fifth element (50) extending between the second element (20) and the third element (30), the fifth element (50) extending from an intermediate portion of the first element (10) through a part. [7] A windscreen antenna (103, 104, 105) for a vehicle according to any one of claims 1 to 6, wherein the inequality 0.16 × λ H × k ≤ L H ≤ 0.60 × λ H × k, where a second total length between the supply electrode (3) and a distal end portion (31) of the third element (30) with L H is designated, a central wavelength of the second frequency band with λ H and a wavelength shortening rate of the window pane (1) is denoted by k. [8] A window antenna (103, 104, 105) for a vehicle according to any one of claims 1 to 7, wherein a second total length between the feed electrode (3) and a distal end portion (31) of the third element (30) is L H and L H is equal to 50 mm or more and 180 mm or less. [9] A window antenna (103, 104, 105) for a vehicle according to any one of claims 1 to 8, wherein the inequality 0.13 × λ V × k ≤ L v ≤ 0.33 × λ V × k, where a first total length between the supply electrode (3) and a distal end portion (21) of the second element (20) is L V is designated, a central wavelength of the first frequency band with λ V and a wavelength shortening rate of the window pane (1) is denoted by k. [10] A window antenna (103, 104, 105) for a vehicle according to any one of claims 1 to 9, wherein a first total length between the feed electrode (3) and a distal end portion (21) of the second element (20) is L V and L V is equal to 130 mm or more and 300 mm or less. [11] A window antenna (103, 104, 105) for a vehicle according to any one of claims 1 to 10, wherein the frame edge (2a) is a frame edge on an upper side of the window frame (2). [12] A window antenna (103, 104, 105) for a vehicle according to any one of claims 1 to 11, wherein the first frequency band is a frequency band in band III of the DAB standard, and the second frequency band is a frequency band for the broadcast wave of digital terrestrial television. [13] Window pane (1) for a vehicle, to which the window antenna (103, 104, 105) for a vehicle according to one of claims 1 to 12 is attached. [14] An antenna system (100) for a vehicle comprising a plurality of glass antennas (103, 104, 105) arranged remotely from each other, each of the plurality of glass antennas (103, 104, 105) being the glass antenna (103, 104, 105) for a vehicle according to any one of claims 1 to 12.

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