GLASS-INTEGRATED ANTENNA AND VEHICLE-USE GLAZING PROVIDED WITH SAME

Abstract

 A glass antenna arranged at a window glass (23) includes a signal-side feeding portion (16) and a ground-side feeding portion (17) that are aligned in a vertical direction; an F-shaped element that is formed into an F-shape by a linear conductor (1) connected to the signal-side feeding portion (16) and extending in the horizontal direction and linear conductors (2, 3) extending in the vertical direction from the linear conductor (1) as an origin; and an L-shaped element formed into an L-shape by a linear conductor (4) connected to the ground-side feeding portion (17) and extending in the horizontal direction and a linear conductor (5) extending upward from the linear conductor (4) as an origin.

Description

TECHNICAL FIELD

[0001] The present invention relates to a glass antenna arranged at a glass plate. The present invention also relates to a window glass for vehicle having the glass antenna.

BACKGROUND ART

[0002] Glass antennas that are capable of receiving DAB (Digital Audio Broadcasting) are known in the prior art (See e.g., Patent Documents 1 to 4). DAB uses two different frequency bands; namely, Band III having a frequency range of 174 to 240 MHz, and L-Band having a frequency range of 1452 to 1492 MHz.

[Prior Art Documents]

[0003] 

[Patent Document 1] Japanese Laid-Open Patent Publication No. 10-327009

[Patent Document 2] Japanese Laid-Open Patent Publication No. 2000-307321

[Patent Document 3] U.S. Patent No. 6924771

[Patent Document 4] European Patent Publication No. 1732160

DISCLOSURE OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0004] In the case where a frequency band is dual-band such as the DAB, it is difficult to design a glass antenna having a reception performance sufficient to support both the bands because the bands are set apart from one another. Thus, there is a demand for a glass antenna having high reception sensitivity that can be used for a dual-band.

[0005] It is an object of the present invention to provide a glass antenna having high reception sensitivity that can be used for a dual-band such as the DAB and a window glass for vehicle having the glass antenna.

MEANS FOR SOLVING THE PROBLEMS

[0006] According to the present invention, in order to achieve the object, there is provided a glass antenna arranged at a glass plate, as viewed from a side facing a surface of the glass plate, includes a first feeding portion, a second feeding portion that is aligned with the first feeding portion, and an antenna conductor including a first antenna element that is connected to the first feeding portion and a second antenna element that is connected to the second feeding portion. One of the first feeding portion or the second feeding portion is a signal-side feeding portion, and the other one of the first feeding portion or the second feeding portion is a ground-side feeding portion. The first antenna element includes an F-shaped element that is formed into an F-shape by a first linear conductor having one end connected either directly or via a connection conductor to the first unit and extending in a horizontal direction, a second linear conductor extending in a vertical direction from another end of the first linear conductor as an origin, and a third linear conductor extending in the same direction as the second linear conductor from an intermediate point of the first linear conductor as an origin. The second antenna element includes an L-shaped element that is formed into an L-shape by a fourth linear conductor having one end connected either directly or via a connection conductor to the second feeding portion and extending in a horizontal direction on a side of the first linear conductor from which the second linear conductor extends and a fifth linear conductor extending in a vertical direction from another end of the fourth linear conductor as an origin.

[0007] According to the present invention, in order to achieve the object, there is provided a window glass includes the glass antenna of the present invention.

EFFECTS OF THE PRESENT INVENTION

[0008] According to an aspect of the present invention, a glass antenna having high reception sensitivity that can be used for a dual-band such as the DAB may be provided.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] 

FIG. 1 is a plan view of a glass antenna 100 for vehicle;

FIG. 2 is a plan view of a glass antenna 200 for vehicle;

FIG. 3 is a plan view of a glass antenna 300 for vehicle;

FIG. 4 is a plan view of a glass antenna 400 for vehicle;

FIG. 5 is a plan view of a glass antenna 500 for vehicle;

FIG. 6 is a plan view of a glass antenna 600 for vehicle;

FIG. 7 is a plan view of a glass antenna 700 for vehicle;

FIG. 8A is a graph representing measurement data of the antenna gain for Band III when a conductor length L3 is varied;

FIG. 8B is a graph representing measurement data of the antenna gain for L-Band when the conductor length L3 is varied;

FIG. 9A is a graph representing measurement data of the antenna gain for Band III when a conductor length L5 is varied;

FIG. 9B is a graph representing measurement data of the antenna gain for L-Band the conductor length L5 is varied;

FIG. 10A is a graph representing measurement data of the antenna gain for Band III when a conductor length L2 is varied;

FIG. 10B is a graph representing measurement data of the antenna gain for L-Band when the conductor length L2 is varied;

FIG. 10C is a graph representing measurement data of the frequency characteristics of the antenna gain for Band III when the conductor length L2 is varied;

FIG. 11A is a graph representing measurement data of the antenna gain for Band III when a conductor length L6 is varied;

FIG. 11B is a graph representing measurement data of the antenna gain for L-Band when the conductor length L6 is varied;

FIG. 12 is a graph representing measurement data of the frequency characteristics of the antenna gain for each glass antenna; and

FIG. 13 is a graph representing measurement data of the frequency characteristics of the antenna gain for each glass antenna.

MODE FOR CARRYING OUT THE INVENTION

[0010] In the following, a mode for carrying out the present invention will be described with reference to the drawings. It is noted that unless specified otherwise, directions in the descriptions below correspond to directions as illustrated in the drawings, and a given reference direction in a drawing corresponds to the direction represented by a corresponding reference symbol or number. Also, in the descriptions below, directional terms such as "parallel" and "perpendicular" are not used in their strict sense and are meant to allow some degree of deviation. Also, the plan views each illustrate a glass antenna as seen from a side facing a glass surface. It is noted that although the plan views correspond to views from inside a vehicle when a window glass including a glass antenna of the present invention is installed in the vehicle, the plan views may also be regarded as views from outside the vehicle. Also, vertical directions in the plan views correspond to vertical directions of the vehicle, and a downside direction in the drawings correspond to a direction toward the road surface. Also, in the case where the window glass corresponds to a side window arranged at a side of the vehicle, right-left directions in the drawings correspond to front-back directions of the vehicle. Further, it is noted that the present invention is not limited to being arranged at a side window of a vehicle and may also be arranged at a rear window mounted at the rear side of a vehicle, a windshield mounted at the front side of a vehicle, or a window glass other than that of a vehicle (e.g., window glass of a building, window glass of a vessel, etc.).

[First Group of Preferred Embodiments]

[0011] FIG. 1 is a plan view of a glass antenna 100 for a vehicle according to a first embodiment of the present invention. FIG. 2 is a plan view of a glass antenna 200 for a vehicle according to a second embodiment of the present invention. The glass antennas 100 and 200 are configured to be arranged at a window glass 23 corresponding to a side window of a vehicle. It is noted that FIGS. 1 and 2 are views from the interior of a vehicle and the left sides of FIGS. 1 and 2 correspond to the rear side of the vehicle.

[0012] A glass antenna according to the present invention includes a first feeding portion, a second feeding portion that is aligned with the first feeding portion, and an antenna conductor that are arranged at a window glass. The antenna conductor includes a first antenna element that is connected to the first feeding portion and a second antenna element that is connected to the second feeding portion. For example, the first feeding portion may be a signal-side feeding portion that is electrically connected to a signal path of an external signal processing unit (e.g., vehicle-mounted amplifier) via a predetermined first conductive member and is made of a conductor having a predetermined area for enabling connection with the first conductive member, and the second feeding portion may be a ground-side feeding portion that is electrically connected to an external ground path (e.g., ground of the signal processing unit or the vehicle body) via a predetermined second conductive member and is made of a conductor having a predetermined area for enabling connection with the second conductive member. The first feeding portion and the second feeding portion comprise a feeding point of the antenna conductor.

[0013] The glass antennas 100 and 200 illustrated in FIGS. 1 and 2 correspond to dipole antennas that are arranged into planar configurations at their corresponding window glasses 23. The glass antennas 100 and 200 each include an antenna conductor, a signal-side feeding portion 16, and a ground-side feeding portion 17. The signal-side feeding portion 16 and the ground-side feeding portion 17 are arranged to be vertically spaced apart from one another along a rim 23a of the window glass 23, the signal-side feeding portion 16 being positioned at the upper side and the ground-side feeding portion 17 being positioned at the lower side. The glass antennas 100 and 200 each include as patterns of the antenna conductor at least a first antenna element connected to the signal-side feeding portion 16 and a second antenna element connected to the ground-side feeding portion 17. It is noted that in other embodiments, the positions of the signal-side feeding portion 16 and the ground-side feeding portion 17 may be reversed, or the signal-side feeding portion 16 and the ground-side feeding portion 17 may be spaced apart in the horizontal direction, for example.

[0014] The first antenna element includes an F-shaped element that is formed into an F-shape by a first linear conductor having one end connected either directly or via a connection conductor to the signal-side feeding portion 16 and extending in a horizontal direction, a second linear conductor extending in a vertical direction from the other end of the first linear conductor as an origin, and a third linear conductor extending in the same direction as the second linear conductor from an intermediate point of the first linear conductor as an origin. For example, the second linear conductor and the third linear conductor may extend in a direction substantially perpendicular to the extending direction of the first linear conductor to form the F-shaped element.

[0015] In FIGS. 1 and 2, a linear conductor 1 as an exemplary embodiment of the first linear conductor extends linearly in the leftward direction from end "a" connected to the signal-side feeding portion 16 as an origin, a linear conductor 2 as an exemplary embodiment of the second linear conductor extends linearly in the downward direction from end "c" corresponding to the left side extending end of the linear conductor 1 as an origin, and a linear conductor 3 as an exemplary embodiment of the third linear conductor extends linearly in the downward direction from an intermediate point "b" of the leftward extending linear conductor 1 as an origin. The linear conductor 2 extends downward to end "d", and the linear conductor 3 extends downward to end "e". It is noted that the intermediate point "b" corresponds to a point between end "a" and end "c" of the linear conductor 1.

[0016] The second antenna element includes an L-shaped element that is formed into an L-shape by a fourth linear conductor and a fifth linear conductor. The fourth linear conductor has one end connected either directly or via a connection conductor to the ground-side feeding portion 17 and extends horizontally on a side of the first linear conductor from which the second linear conductor extends. The fifth linear conductor extends vertically between the second linear conductor and the third linear conductor from the other end of the fourth linear conductor as an origin. For example, the fifth linear conductor may extend in a direction substantially perpendicular to the extending direction of the fourth linear conductor to form the L-shaped element.

[0017] In FIG. 1, a linear conductor 4 as an exemplary embodiment of the fourth linear conductor extends linearly in the leftward direction at the lower side of the linear conductor 1 (linear conductor 2 extending direction side) from end "f" connected to the ground-side feeding portion 17 as an origin, and a linear conductor 5 as an exemplary embodiment of the fifth linear conductor extends upward between the linear conductor 2 and the linear conductor 3 from end "h" corresponding to the left side extending end of the linear conductor 4 as an origin. The linear conductor 5 extends upward to end "i".

[0018] In FIG. 2, a linear conductor 7 is illustrated as a connection conductor that connects the linear conductor 4 to the ground-side feeding portion 17. The linear conductor 7 extends linearly in the downward direction from end "g" connected to the ground-side feeding portion 17 as an origin. The linear conductor 7 is configured to connect end "g" to end "f" corresponding to one end of linear conductor 4. It is noted that the linear conductor 7 does not necessarily have to extend vertically downward and may alternatively extend diagonally toward the lower left side from end "g" connected to the ground-side feeding portion 17, for example.

[0019] It is noted that although FIG. 2 illustrates an exemplary arrangement in which end "f" of the linear conductor 4 is connected to the ground-side feeding portion 17 via the linear conductor 7, in other alternative arrangements, end "a" of the linear conductor 1 may be connected to the signal-side feeding portion 16 via a connection conductor, for example.

[0020] Also, in one embodiment, the first antenna element of the glass antennas 100 and 200 may include a sixth linear conductor that is connected to end "c" corresponding to the other end of the first linear conductor and extends in a horizontal direction. In FIGS. 1 and 2, a linear conductor 6 as an exemplary embodiment of the sixth linear conductor extends linearly in the horizontal direction from end "c" of the linear conductor 1 as an origin. The linear conductor 6 extends in the leftward direction to end "j".

[0021] It is noted that although the antenna conductor illustrated in FIGS 1 and 2 has the first antennal element and the second antenna element extending in the leftward direction, the first antenna element and the second antenna element may alternatively be arranged to extend in the rightward direction. That is, the arrangements of FIGS. 1 and 2 may be rearranged to be horizontally line-symmetric with respect to the signal-side feeding portion. Also, the positions of the signal-side feeding portion, the first antenna element, the ground-side feeding portion, and the second antenna element may alternatively be reversed. That is, the arrangements of FIGS. 1 and 2 may be rearranged to be line-symmetric or point-symmetric with respect to the signal-side feeding portion.

[0022] In the present embodiment, broadcasting frequency bands to be received include a predetermined first broadcasting frequency band and a predetermined second broadcasting frequency band that is lower than the first broadcasting frequency band. Assuming λ₀₁ represents the wavelength in air of the central frequency of the first broadcasting frequency band, k₁ represents the shortening coefficient of wavelength by glass (where k₁ = 0.74), and λ_g1=λ₀₁· λ₁ represents the wavelength in glass, favorable results may be obtained in terms of improving the antenna gain for the first broadcasting frequency band in the glass antennas illustrated in FIGS. 1 and 2 when the conductor length L3 of the linear conductor 3 corresponding to the third linear conductor, which is a vertical component of the first antenna element, is arranged to be greater than or equal to (1/5) λ_g1, and more preferably greater than or equal to (1/4)λ_g1, provided the conductor length L3 is confined within a range that keeps the linear conductor 3 from coming into contact with the linear conductor 4.

[0023] In a case where the first broadcasting frequency band corresponds to L-Band (1452 to 1492 MHz), the central frequency of the first broadcasting frequency band is 1472 MHz. Thus, to improve the antenna gain for L-Band, assuming the speed of the radio wave is 3.0×10⁸ m/s, the conductor length L3 of the linear conductor 3 is preferably arranged to be greater than or equal to 30 mm, and more preferably greater than or equal to 40 mm. Also, in consideration of the occupying area of the glass antenna, the conductor length L3 is preferably arranged to be less than or equal to 80 mm.

[0024] As described above, in the present embodiment, the broadcasting frequency bands to be received include the predetermined first broadcasting frequency band and the predetermined second broadcasting frequency band that is lower than the first broadcasting frequency band. Assuming λ₀₂ represents the wavelength in air of the central frequency of the second broadcasting frequency band, k₂ represents the shortening coefficient of wavelength by glass (where k₂ = 0.54), and λ_g2=λ₀₂· k₂ represents the wavelength in glass, favorable results may be obtained in terms of improving the antenna gain for the second broadcasting frequency band in the glass antennas illustrated in FIGS. 1 and 2 when the conductor length L5 of the linear conductor 5 as the fifth linear conductor, which is a vertical component of the second antenna element, is arranged to be greater than or equal to (1/26) λ_g2, and more preferably, greater than or equal to (1/20) λ_g2, provided the conductor length L5 is confined within a range that keeps the linear conductor 5 from coming into contact with the linear conductor 1.

[0025] In the case where the second broadcasting frequency band corresponds to Band III (174 to 240 MHz), the central frequency of the second broadcasting frequency is 207 MHz. Thus, to improve the antenna gain for Band III, assuming the speed of the radio wave is 3.0×10⁸ m/s, the conductor length L5 of the linear conductor 5 is preferably arranged to be greater than or equal to 30 mm, and more preferably, greater than or equal to 40 mm. Increasing the conductor length L5 may be particularly effective in improving the antenna gain for a high frequency band from 200 MHz and higher of the Band III frequency band. Also, it is noted that in consideration of the occupying area of the glass antenna, the conductor length L5 is preferably arranged to be less than or equal to 80 mm.

[0026] Also, in the glass antennas illustrated in FIGS. 1 and 2, favorable results may be obtained in terms of improving the antenna gain for Band III when the conductor length L2 of the linear conductor 2 corresponding to the second linear conductor, which is a vertical component of the first antenna element, is arranged to be greater than or equal to 30 mm and less than or equal to 120 mm, provided the conductor length 2 is confined within a range that keeps the linear conductor 2 from coming into contact with other conductors and within a range that keeps the linear conductor 2 from extending outside the window glass 23. The conductor length L2 is more preferably arranged to be greater than or equal to 30 mm and less than or equal to 100 mm. Also, favorable results may be obtained in terms of improving the antenna gain for L-Band when the conductor length L2 is arranged to be greater than or equal to 40 mm and less than or equal to 100 mm.

[0027] Also, in the glass antennas illustrated in FIGS. 1 and 2, favorable results may be obtained in terms of improving the antenna gain for Band III when the conductor length L6 of the linear conductor 6 corresponding to the sixth linear conductor, which is a horizontal component of the first antenna element, is arranged to be greater than or equal to 20 mm and less than or equal to 100 mm, provided the conductor length L6 is within a range that keeps the linear conductor 6 from coming into contact with other conductors and within a range that keeps the linear conductor 6 from extending outside the window glass 23. Increasing the conductor length L6 may be particularly effective in improving the antenna gain for a low frequency band from 220 MHz and lower of the Band III frequency band. Also, favorable results may be obtained in terms of improving the antenna gain for L-Band when the conductor length L6 is arranged to be greater than or equal to 20 mm and less than or equal to 60 mm.

[0028] Also, in the glass antennas illustrated in FIGS. 1 and 2, favorable results may be obtained in terms of improving the antenna gain for Band III and L-Band when the distance between the linear conductor 2 and the linear conductor 5 that are arranged in parallel is greater than or equal to 2 mm and less than or equal to 20 mm.

[0029] FIG. 3 is a plan view of a glass antenna 300 for a vehicle according to a third embodiment of the present invention. FIG. 4 is a plan view of a glass antenna 400 for a vehicle according to a fourth embodiment of the present invention. It is noted that features of the third and fourth embodiments and advantages achieved by these features that are identical to those of the above-described embodiments are omitted. In the glass antennas 300 and 400 illustrated in FIGS. 3 and 4, the positions of the linear conductors 2, 3, and 5 are altered from those of the glass antenna 200 illustrated in FIG. 2.

[0030] In FIG. 3, the linear conductors 2 and 3 that are connected to the signal-side feeding portion 16 via the linear conductor 1 are arranged to extend vertically at a region on a side of the linear conductor 5 that is opposite a side on which the signal-side feeding portion 16 and the ground-side feeding portion 17 are arranged of the linear conductor 5 that is connected to the ground-side feeding portion 17 via the linear conductors 4 and 7. In other words, the linear conductor 5 is arranged to extend vertically at a region closer toward the signal-side feeding portion 16 and the ground-side feeding portion 17 with respect to the linear conductors 2 and 3.

[0031] In FIG. 4, the linear conductors 2 and 3 that are connected to the signal-side feeding portion 16 via the linear conductor 1 are arranged to extend vertically at a region closer toward the signal-side feeding portion 16 and the ground-side feeding portion 17 with respect to the linear conductor 5 that is connected to the ground-side feeding portion 17 via the linear conductors 4 and 7. In other words, the linear conductor 5 is arranged to extend vertically at a region on a side opposite the side on which the signal-side feeding portion 16 and the ground-side feeding portion 17 are arranged with respect to the linear conductors 2 and 3.

[0032] It is noted that although the antenna conductors illustrated in FIGS. 3 and 4 have the first antenna element and the second antenna element extending in the leftward direction, the first antenna element and the second antenna element may alternatively be arranged to extend in the rightward direction. That is, the first antenna element and the second antenna element illustrated in FIGS. 3 and 4 may be rearranged to be line-symmetrical with respect to the signal-side feeding portion. Also, the arrangement of the signal-side feeding portion, the first antenna element, the ground-side feeding portion, and the second antenna element may be reversed vertically. That is, the arrangements illustrated in FIGS. 3 and 4 may be rearranged to be line-symmetrical in the vertical direction or point-symmetrical with respect to the signal-side feeding portion.

[0033] According to an aspect of the embodiments illustrated in FIGS. 1 to 4, by electrically connecting the signal-side feeding portion 16 to a signal path of an external signal processing device (e.g., vehicle-mounted amplifier) via a predetermined first conductive member, and electrically connecting the ground-side feeding portion 17 to an external ground path (e.g., ground of the signal processing device) via a predetermined second conductive member, reception characteristics compatible with a dual-band such as the DAB may be obtained. Moreover, by arranging the glass antenna at the window glass 23 in a manner such that at least one or more of the linear conductors that extend in the upward or downward direction such as the linear conductor 2, the linear conductor 3, the linear conductor 5, and/or the linear conductor 7 includes a vertical component that is perpendicular to the ground surface (i.e., horizontal plane), reception sensitivity for the radio wave of a vertical polarization wave of a dual-band such as the DAB may be further improved. It is noted that the mounting angle at which the window glass 23 is mounted to the vehicle is preferably arranged to be 30 to 90 degrees, and more preferably 60 to 90 degrees with respect to the ground surface.

[0034] As the first and second conductor members, a feeder cable such an AV cable or a coaxial cable may be used, for example. In the case of using a coaxial cable, the internal conductor of the coaxial cable may be electrically connected to the signal-side feeding portion 16, and the external conductor of the coaxial cable may be electrically connected to the ground-side feeding portion 17. Also, in one embodiment, a male connector may be attached to the front end of the coaxial cable and a female connector may be mounted to the signal-side feeding portion 16 and the ground-side feeding portion 17. By using such connectors, the internal conductor of the coaxial cable may be easily attached to the signal-side feeding portion 16 and the external conductor of the coaxial cable may be easily attached to the ground-side feeding portion 17. Further, in one embodiment, protruding conductive members may be arranged at the signal-side feeding portion 16 and the ground-side feeding portion 17 so that the protruding conductive members may come into engaging contact with connection parts arranged at a flange of the vehicle to which the window glass 23 is mounted.

[0035] According to another aspect of the embodiments illustrated in FIGS. 1 to 4, even when the length of the third linear conductor is tuned to enable reception of a radio wave of the higher frequency band of the dual-band according to a predetermined reception criteria, such adjustment may be implemented without substantially affecting the reception characteristics for the radio wave of the lower frequency band of the dual-band. Similarly, even when the length of the fifth linear conductor is tuned to enable reception of a radio wave of the lower frequency band of the dual-band according to a predetermined reception criteria, such adjustment may be implemented without substantially affecting the reception characteristics for the radio wave of the higher frequency band of the dual-band. That is, tuning may be facilitated in the glass antennas of the above embodiments.

[0036] It is noted that the term "end" used in the present descriptions may refer to a start point or an endpoint of an extending direction of a linear conductor. The term may also be used to refer to portions of the linear conductor in the vicinity of such start point or endpoint. Also, connection parts for connecting the linear conductors may be arranged to have some curvature.

[0037] The antenna conductors, the signal-side feeding portion 16, and the ground-side feeding portion 17 may be formed by printing corresponding patterns using a paste including conductive metal such as a silver paste on the inner surface of the window glass 23 at the interior side of the vehicle, for example. However, the present invention is not limited to such an example. In other examples, a line or a foil made of conductive material such as copper may be arranged on the inner surface or the outer surface of the window glass. The conductive material may be attached to the surface of the window glass using adhesive or the like, or the conductive material may alternatively be arranged within the window glass, for example.

[0038] The shapes of the signal-side feeding portion 16 and the ground-side feeding portion 17, and the distance between the signal-side feeding portion 16 and the ground-side feeding portion 17 may be determined according to the shapes of the mounting faces of the above conductive members and connectors and the distance between these mounting faces. For example, the signal-side feeding portion 16 and the ground-side feeding portion 17 may be arranged into square shapes, nearly square shapes, rectangular shapes, nearly rectangular shapes, and other quadrangular or polygonal shapes. The signal-side feeding portion 16 and the ground-side feeding portion 17 may also be arranged into circular shapes, nearly circular shapes, oval shapes, or nearly oval shapes, for example. Also, the areas of the signal-side feeding portion 16 and the ground-side feeding portion 17 may be arranged to be the same or different.

[0039] In one embodiment, a conductive layer including the antenna conductor may be arranged inside or on the surface of a synthetic resin film, and the synthetic resin film including the conductive layer may be arranged on the inner surface or outer surface of the window glass plate to fabricate a glass antenna. In a further embodiment, a flexible circuit board on which the antenna conductor is formed may be arranged on the inner surface or outer surface of the window glass to fabricate the glass antenna.

[0040] In another embodiment, a masking film may be arranged on the surface of the window glass 23, and the signal-side feeding portion 16, the ground-side feeding portion 17, and a part or all of the antenna conductor may be arranged on the masking film. It is noted that a film made of ceramic such as a black ceramic film may be used as the masking film, for example. In this way, the antenna conductor arranged on the masking film may be invisible from outside the vehicle by the masking film to thereby improve the design of the window glass. In the case of using the masking film in the arrangements illustrated in the drawings, the signal-side feeding portion 16, the ground-side feeding portion 17, and a part of the antenna conductor may be arranged on the masking film (i.e., between the rim of the masking film and the rim 23a of the window glass 23) so that only fine lines corresponding to a part of the antenna conductor may be seen from outside the vehicle and the arrangements may be improved from a design perspective.

[0041] It is particularly noted that favorable results in terms of improving the antenna gain for Band III may be obtained in the case where at least one linear conductor that is connected to the signal-side feeding portion 16 (e.g., linear conductor 3) extends vertically at a region closer toward the signal-side feeding portion 16 with respect to at least one linear conductor that is connected to the ground-side feeding portion 17 (e.g., linear conductor 5) as illustrated in FIGS. 1, 2, and 4, for example.

[Second Group of Preferred Embodiments]

[0042] FIG. 5 is a plan view of a glass antenna 500 for a vehicle according to a fifth embodiment of the present invention. FIG. 6 is a plan view of a glass antenna 600 for a vehicle according to a sixth embodiment of the present invention. FIG. 7 is a plan view of a glass antenna for a vehicle according to a seventh embodiment of the present invention. It is noted that in the following descriptions, features of the embodiments illustrated in FIGS. 5 to 7 and advantages obtained by these features that are identical to those of the previously-described embodiments are omitted.

[0043] As one of the differences between the glass antennas illustrated in FIGS. 1 to 4 and the glass antennas illustrated in FIGS. 5 to 7, in the glass antennas illustrated in FIGS. 5 to 7 the first feeding portion corresponds to the ground-side feeding portion 17 and the second feeding portion corresponds to the signal-side feeding portion 16.

[0044] Also, while the glass antennas illustrated in FIGS. 1 to 4 have the first antenna element including the F-shaped element that is formed into an F-shape connected to the signal-side feeding portion 16, the glass antennas illustrated in FIGS. 5 to 7 has the first antenna element including an F-shaped element that is formed into an F-shape connected to the ground-side feeding portion 17. Further, while the glass antennas illustrated in FIGS. 1 to 4 have the second antenna element including the L-shaped element that is formed into an L-shape connected to the ground-side feeding portion 17, the glass antennas illustrated in FIGS. 5 to 7 has the second antenna element including an L-shaped element that is formed into an L-shape connected to the signal-side feeding portion 16.

[0045] In FIGS. 5 to 7, the first antenna element includes the F-shaped element that is formed into an F-shape by a first linear conductor having one end connected either directly or via a connection conductor to the ground-side feeding portion 17 and extending in a horizontal direction, a second linear conductor extending vertically from the other end of the first linear conductor as an origin, and a third linear conductor extending in the same direction as the second linear conductor from an intermediate point of the first linear conductor as an origin. For example, the second linear conductor and the third linear conductor may be arranged to extend in a direction substantially perpendicular to the extending direction of the first linear conductor to form the F-shaped element.

[0046] In FIGS. 5 to 7, a linear conductor 11 as an exemplary embodiment of the first linear conductor extends linearly in the leftward direction from end "a1" that connects the linear conductor 11 to the ground-side feeding portion 17 as an origin, a linear conductor 12 as an exemplary embodiment of the second linear conductor extends linearly in the upward direction from end "c1" corresponding to the left side extending end of the linear conductor 11 as an origin, and a linear conductor 13 as an exemplary embodiment of the third linear conductor extends linearly in the upward direction from an intermediate point "b1" of the leftward extending linear conductor 11 as an origin. The linear conductor 12 extends upward to end "d1", and the linear conductor 13 extends upward to end "e1". It is noted that the intermediate point "b1" corresponds to a point between end "a1" and end "c1" of the linear conductor 11.

[0047] Also, in FIGS. 5 to 7, a linear conductor 19 is illustrated as a connection conductor for connecting the first linear conductor to the ground-side feeding portion 17. The linear conductor 19 extends linearly in the downward direction from end "g1" that connects the linear conductor 19 to the ground-side feeding portion 17 as an origin. The linear conductor 19 is configured to connect end "g1" to end "c1" corresponding to one end of the linear conductor 11. It is noted that the linear conductor 19 does not necessarily have to extend vertically downward and may alternatively be arranged to extend diagonally toward the lower-left side from end "g1" that is connected to the ground-side feeding portion 17, for example.

[0048] Also, in FIGS. 5 to 7, the second antenna element includes the L-shaped element that is formed into an L-shape by a fourth linear conductor and a fifth linear conductor. The fourth linear conductor has one end connected either directly or via a connection conductor to the signal-side feeding portion 16 and extends in a horizontal direction on a side of the first linear conductor on which the second linear conductor extends. The fifth linear conductor extends vertically from the other end of the fourth linear conductor as an origin. For example, the fifth linear conductor may be arranged to extend in a direction substantially perpendicular to the extending direction of the fourth linear conductor to form the L-shaped element.

[0049] In FIG. 5, a linear conductor 14 as an exemplary embodiment of the fourth linear conductor extends linearly in the leftward direction from end "f1" that connects the linear conductor 14 to the signal-side feeding portion 16 as an origin. The linear conductor 14 extends at a region on the upper side of the linear conductor 11 (linear conductor 12 extending direction side). Also, a linear conductor 15 as an exemplary embodiment of the fifth linear conductor extends downward between the linear conductor 12 and the linear conductor 13 from end "h1" corresponding to the left side extending end of the linear conductor 14 as an origin. The linear conductor 15 is arranged to extend downward to end "i1".

[0050] In FIG. 5, the linear conductor 15 that is connected to the signal-side feeding portion 16 via the linear conductor 14 extends vertically at a region closer toward the signal-side feeding portion 16 and the ground-side feeding portion 17 with respect to the linear conductor 12 that is connected to the ground-side feeding portion 17 via the linear conductors 11 and 19.

[0051] In FIG. 6, the linear conductor 14 as an exemplary embodiment of the fourth linear conductor extends linearly in the leftward direction from end "f1" that connects the linear conductor 14 to the signal-side feeding portion 16 as an origin. The linear conductor 14 extends at a region on the upper side of the linear conductor 11 (linear conductor 12 extending direction side). Also, the linear conductor 15 as an exemplary embodiment of the fifth linear conductor extends downward from end "h1" corresponding to the left side extending end of the linear conductor 14 as an origin. The linear conductor 15 extends at a region closer toward the signal-side feeding portion 16 and the ground-side feeding portion 17 with respect to the linear conductors 12 and 13. In other words, the linear conductors 12 and 13 are arranged to extend vertically at a region on the opposite side of the linear conductor 15 from the side on which the signal-side feeding portion 16 and the ground-side feeding portion 17 are arranged.

[0052] In FIG. 7, the linear conductor 14 as an exemplary embodiment of the fourth linear conductor extends linearly in the leftward direction from end "f1" that connects the linear conductor 14 to the signal-side feeding portion 16 as an origin. The linear conductor 14 extends at a region on the upper side of the linear conductor 11 (linear conductor 12 extending direction side). Also, the linear conductor 15 as an exemplary embodiment of the fifth linear conductor extends downward from end "h1" corresponding to the left side extending end of the linear conductor 14 as an origin. The linear conductor 15 extends at a region on the opposite side of the signal-side feeding portion 16 and the ground-side feeding portion 17 with respect to the linear conductor 12 and the linear conductor 13. The linear conductor 15 is arranged to extend downward to end "i1".

[0053] In FIG. 7, the linear conductor 15 that is connected to the signal-side feeding portion 16 via the linear conductor 14 extends vertically at a region on the opposite side of the signal-side feeding portion 16 and the ground-side feeding portion 17 with respect to the linear conductors 12 and 13 that are connected to the ground-side feeding portion 17 via the linear conductors 11 and 19. In other words, the linear conductors 12 and 13 extend vertically at a region closer toward the signal-side feeding portion 16 and the ground-side feeding portion 17 with respect to the linear conductor 15.

[0054] Also, the first antenna element of the glass antennas illustrated in FIGS. 5 to 7 may include a sixth linear conductor that extends horizontally and is connected to end "h1" corresponding to the other end of the fourth linear conductor. In FIGS. 5 to 7, a linear conductor 18 as an exemplary embodiment of the sixth linear conductor extends linearly in the leftward direction from end "h1" as an origin. The linear conductor 18 is arranged to extend leftward to end "j1".

[0055] It is noted that although end "a1" of the linear conductor 11 is arranged to be connected to the ground-side feeding portion 17 via the linear conductor 19 in the embodiments illustrated in FIGS. 5 to 7, in other embodiments, end "f1" of the linear conductor 14 may be arranged to be connected to the signal-side feeding portion 16 via a connection conductor.

[0056] Also, although the antenna conductors illustrated in FIGS. 5 to 7 has the first antenna element and the second antennal element extending in the leftward direction, the first antenna element and the second antenna element may alternatively be arranged to extend in the rightward direction. That is, arrangements that are horizontally line symmetric to the arrangements illustrated in FIGS. 5 to 7 may be used, for example. In other embodiments, the positions of the signal-side feeding portion, the first antenna element, the ground-side feeding portion, and the second antenna element may be reversed vertically. That is, arrangements that are vertically line-symmetric or point-symmetric to the arrangements illustrated in FIGS. 5 to 7 may be used, for example.

[0057] According to an aspect the embodiments illustrated in FIGS. 5 to 7, by electrically connecting the signal-side feeding portion 16 to a signal path of an external signal processing device (e.g., vehicle-mounted amplifier) via a predetermined first conductive member, and electrically connecting the ground-side feeding portion 17 to an external ground path (e.g., ground of the signal processing device) via a predetermined second conductive member, reception characteristics compatible with a dual-band such as the DAB may be obtained.

[0058] Further, favorable results may be obtained in terms of improving the antenna gain for Band III in arrangements such as those illustrated in FIGS. 5 and 6 where at least one linear conductor that is connected to the signal-side feeding portion 16 (linear conductor 15) extends vertically at a region closer toward the signal-side feeding portion 16 with respect to at least one linear conductor that is connected to the ground-side feeding portion 17 (linear conductor 12). Also, favorable results may be obtained in terms of improving the antenna gain for Band III in an arrangement such as that illustrated in FIG. 5 where the linear conductor 15 extends vertically between the linear conductor 12 and the linear conductor 13.

[Working Examples]

[0059] In the following, working examples of the glass antenna and window glass of the present invention applied to a window glass for vehicle are described. First, measurement results of measuring the antenna gain of an glass antenna for automobile fabricated by mounting the glass antenna illustrated in FIG. 1 or 2 at a side window of a vehicle are described.

[0060] The window glass for automobile having the glass antenna formed thereon was mounted to a window frame of an automobile placed on a turntable to be tilted approximately 75 degrees with respect to a horizontal plane, and the antenna gain of the automobile glass antenna was measured in this state. Connectors were attached to the signal-side feeding portion and the ground-side feeding portion to establish connection with a network analyzer via feeder cables. The turntable was arranged to rotate so that radio waves may be horizontally irradiated on the window glass from all directions.

[0061] The antenna gain was measured by setting the vehicle center of the automobile having the window glass with the glass antenna to the center of the turntable and rotating the automobile 360 degrees. Specifically, at every rotational angle of 5 degrees, the antenna gain was measured at intervals of 3 MHz within the Band III frequency band and at intervals of 1.7 MHz within the L-Band frequency band. The position and elevation angle of the antenna conductor and outgoing radio was substantially horizontal (elevation angle = 0°, assuming the elevation angle of a plane parallel to the ground = 0° and the elevation angle of the zenith direction = 90°). The antenna gain was normalized based on the half-wave dipole antenna so that the antenna gain of the half-wave dipole antenna may be equal to 0 dB.

[Example 1]

[0062] FIGS. 8A and 8B represent measurement data of the antenna gain of a high frequency glass antenna for an automobile that is fabricated by mounting the glass antenna 200 illustrated in FIG. 2 to a side window of an automobile, the antenna gain being measured while varying the conductor length L3 of the linear conductor 3. The vertical axis of FIG. 8A represents the average value of the antenna gains for Band III (174 to 240 MHz) measured at intervals of 3 MHz and at rotational angle intervals of 5 degrees. The vertical axis of FIG. 8B represents the average value of the antenna gains for L-Band (1452 to 1492 MHz) measured at intervals of 1.7 MHz and at rotational angle intervals of 5 degrees.

[0063] Assuming dimensions are represented in millimeter (mm) units, the dimensions of parts of the glass antenna that is subject to the measurements of FIGS. 8A and 8B are as follows:

L1: 60

L2: 80

L4: 50

L5: 50

L6: 35

L7: 30

It is noted that L* (where * is a numeral) represents the conductor length of the corresponding linear conductor *. The conductor width of each of the linear conductors is 0.8 mm. The signal-side feeding portion 16 and the ground-side feeding portion 17 are arranged into square shapes having a side dimension of 12 mm. The distance between the signal-side feeding portion 16 and the ground-side feeding portion 17 is 13 mm.

[0064] As can be appreciated from FIGS. 8A and 8B, the antenna gain for L-Band can be improved by increasing the conductor length L3 of the linear conductor 3. For example, as illustrated in FIG. 8B, when the conductor length L3 of the linear conductor 3 is greater than or equal to 30 mm, the antenna gain for L-Band may be improved while the antenna gain for Band III may be prevented from substantially changing.

[Example 2]

[0065] FIGS. 9A and 9B represent measurement data of the antenna gain of a high frequency glass antenna for an automobile that is fabricated by mounting the glass antenna 200 illustrated in FIG. 2 to a side window of an automobile, the antenna gain being measured while varying the conductor length L5 of the linear conductor 5. The vertical axis of FIG. 9A represents the average value of the antenna gains for Band III (174 to 240 MHz) measured at intervals of 3 MHz and at rotational angle intervals of 5 degrees. The vertical axis of FIG. 9B represents the average value of the antenna gains for L-Band (1452 to 1492 MHz) measured at intervals of 1.7 MHz and at rotational angle intervals of 5 degrees.

[0066] Assuming dimensions are represented in millimeter (mm) units, the dimensions of parts of the glass antenna that is subject to the measurements of FIGS. 9A and 9B are as follows:

L1: 60

L2: 80

L3: 60

L4: 50

L6: 35

L7: 30

It is noted that other dimensions are the same as those of Example 1.

[0067] As can be appreciated from FIGS. 9A and 9B, the antenna gain for L-Band can be improved by increasing the conductor length L5 of the linear conductor 5. For example, as illustrated in FIG. 9A, when the conductor length L5 of the linear conductor 5 is greater than or equal to 30 mm, the antenna gain for Band III may be improved while the antenna gain for the L-Band may be prevented from substantially changing.

[Example 3]

[0068] FIGS. 10A to 10C represent measurement data of the antenna gain of a high frequency glass antenna for an automobile that is fabricated by mounting the glass antenna 200 illustrated in FIG. 2 to a side window of an automobile, the antenna gain being measured while varying the conductor length L2 of the linear conductor 2. The vertical axis of FIG. 10A represents the average value of the antenna gains for Band III (174 to 240 MHz) measured at intervals of 3 MHz and at rotational angle intervals of 5 degrees. The vertical axis of FIG. 10B represents the average value of the antenna gains for L-Band (1452 to 1492 MHz) measured at intervals of 1.7 MHz and at rotational angle intervals of 5 degrees. The vertical axis of FIG. 10C represents the average value of the antenna gains measured at rotation angle intervals of 5 degrees for each frequency.

[0069] Assuming dimensions are represented in millimeter (mm) units, the dimensions of parts of the glass antenna that is subject to the measurements of FIGS. 10A to 10C are as follows:

L1: 60

L3: 60

L4: 50

L5: 50

L6: 35

L7: 30

It is noted that other dimensions are the same as those of Example 1.

[0070] As can be appreciated from FIG. 10A, the antenna gain for Band III may be improved by arranging the conductor length L2 of the linear conductor 2 to be greater than or equal to 30 mm and less than or equal to 100 mm. Moreover, as can be appreciated from FIG. 10C, as the conductor length L2 of the linear conductor 2 is increased, the antenna gain for a high frequency band from 210 MHz and higher of the Band III frequency band may be improved (e.g., comparing the cases where the conductor length L2 is equal to 10 mm and 100 mm, the antenna gain may be improved by approximately 4 dB). Also, as can be appreciated from FIG. 10B, the antenna gain for L-Band may be improved when the conductor length L2 of the linear conductor 2 is arranged to be greater than or equal to 40 mm and less than or equal to 100 mm.

[Example 4]

[0071] FIGS. 11A and 11B represent measurement data of the antenna gain of a high frequency glass antenna for an automobile that is fabricated by mounting the glass antenna 200 illustrated in FIG. 2 to a side window of an automobile, the antenna gain being measured while varying the conductor length L6 of the linear conductor 6. The vertical axis of FIG. 11A represents the average value of the antenna gains for Band III (174 to 240 MHz) measured at intervals of 3 MHz and at rotational angle intervals of 5 degrees. The vertical axis of FIG. 11B represents the average value of the antenna gains for L-Band (1452 to 1492 MHz) measured at intervals of 1.7 MHz and at rotational angle intervals of 5 degrees.

[0072] Assuming dimensions are represented in millimeter (mm) units, the dimensions of parts of the glass antenna that is subject to the measurements of FIGS. 11A and 11B are as follows:

L1: 60

L2: 80

L3: 60

L4: 50

L5: 50

L7: 30

It is noted that other dimensions are the same as those of Example 1.

[0073] As can be appreciated from FIG. 11A, the antenna gain for Band III may be improved when the conductor length L6 of the linear conductor 6 is arranged to be greater than or equal to 20 mm and less than or equal to 100 mm. Also, as can be appreciated from FIG. 11B, the antenna gains for L-Band may be improved when the conductor length L6 of the linear conductor 6 is arranged to be greater than or equal to 20 mm and less than or equal to 60 mm.

[Example 5]

[0074] FIG. 12 represents measurement data of the antenna gains for Band III of high frequency glass antennas for automobiles fabricated by mounting the glass antennas 200, 300, and 400 respectively illustrated in FIGS. 2, 3, and 4 to side windows of the automobiles. The vertical axis of FIG. 12 represents the average value of antenna gains measured at rotational angle intervals of 5 degrees for each frequency.

[0075] Assuming dimensions are represented in millimeter (mm) units, the dimensions of parts of the glass antennas that are subject to the measurements of FIG. 12 are as follows:

[Glass Antenna 200]

[0076] 

L1: 60

L2: 40

L3: 60

L4: 50

L5: 60

L6: 50

L7: 30

H1: 35

between a and b: 40

[Glass Antenna 300]

[0077] 

L1: 70

L2: 60

L3: 40

L4: 50

L5: 60

L6: 40

L7: 30

H1: 35

between a and b: 60

[Glass Antenna 400]

[0078] 

L1: 40

L2: 60

L3: 60

L4: 50

L5: 60

L6: 70

L7: 30

H1: 35

between a and b: 30

It is noted that other dimensions in the present example are identical to those of Example 1.

[0079] The average values of the antenna gains at the Band III frequency band are -1.0 dBd for the glass antenna 200, -1.8 dBd for the glass antenna 300, and -0.9 dBd for the glass antenna 400. As can be appreciated from above, adequate antenna gains may be obtained for the Band III frequency band in the glass antennas 200, 300, and 400 having an F-shaped element and an L-shaped element facing each other.

[0080] It is particularly noted that the antenna gain for Band III may be further improved in an arrangement such as those of glass antennas 200 and 400 in which at least one of the linear conductors 2 and 3 connected to the signal-side feeding portion 16 extends vertically at a region closer toward the signal-side feeding portion1 16 and the ground-side feeding portion 17 with respect to the linear conductor 5 that is connected to the ground-side feeding portion 17.

[Example 6]

[0081] FIG. 13 represents measurement data of the antenna gains for Band III of high frequency glass antennas for automobiles fabricated by mounting the glass antennas 200, 500, 600, and 700 respectively illustrated in FIGS. 2, 5, 6, and 7 to side windows of the automobiles. The vertical axis of FIG. 13 represents the average value of antenna gains measured at rotational angle intervals of 5 degrees for each frequency.

[0082] Assuming dimensions are represented in millimeter (mm) units, the dimensions of parts of the glass antennas that are subject to the measurements of FIG. 13 are as follows:

[Glass Antenna 200]

Same as Example 5

[Glass Antenna 500]

[0083] 

L11: 50

L12: 40

L13: 60

L14: 40

L15: 60

L18: 70

L19: 30

H1: 35

between a1 and b1: 30

[Glass Antenna 600]

[0084] 

L11: 60

L12: 60

L13: 30

L14: 40

L15: 60

L18: 70

L19: 30

H1: 35

between a1 and b1: 50

[Glass Antenna 700]

[0085] 

L11: 30

L12: 60

L13: 60

L14: 40

L15: 60

L18: 70

L19: 30

H1: 35

between a1 and b1: 20

It is noted that other dimensions of the present example are the same as those of Example 1.

[0086] The average values of the antenna gains of Band III frequency band are -1.0 dBd for the glass antenna 200, -1.1 dBd for the glass antenna 500, -1.2 dBd for the glass antenna 600, and -1.4 dBd for the glass antenna 700. As can be appreciated from above, adequate antenna gains may be obtained for the Band III frequency band in the glass antennas 200, 500, 600, and 700 having an F-shaped element and an L-shaped element facing each other.

[0087] It is particularly noted that the antenna gain for Band III may be further improved in an arrangement such as those of the glass antennas 500 and 600 in which the linear conductor 15 that is connected to the signal-side feeding portion 16 extends vertically at a region closer toward the signal-side feeding portion 16 and the ground-side feeding portion 17 with respect to at least one of the linear conductors 12 and 13 that are connected to the ground-side feeding portion 17.

[0088] The present application is based on and claims the benefit of priority of Japanese Patent Application No. 2011-023359 filed on February 4, 2011, the entire contents of which are hereby incorporated by reference.

DESCRIPTION OF THE REFERENCE NUMERALS

[0089] 

1 to 7, 11 to 15, 18, 19

LINEAR CONDUCTOR

16

SIGNAL-SIDE FEEDING PORTION

17

GROUND-SIDE FEEDING PORTION

23

WINDOW GLASS

23A

RIM

100, 200, 300, 400, 500, 600, 700

GLASS ANTENNA FOR VEHICLE

Claims

1. A glass antenna that is arranged at a glass plate, as viewed from a side facing a surface of the glass plate, comprising:

a first feeding portion;

a second feeding portion that is aligned with the first feeding portion; and

an antenna conductor including a first antenna element that is connected to the first feeding portion and a second antenna element that is connected to the second feeding portion; wherein

one of the first feeding portion and the second feeding portion is a signal-side feeding portion, and the other one of the first feeding portion and the second feeding portion is a ground-side feeding portion;

the first antenna element includes an F-shaped element that is formed into an F-shape by a first linear conductor having one end connected either directly or via a connection conductor to the first feeding portion and extending in a horizontal direction, a second linear conductor extending in a vertical direction from another end of the first linear conductor as an origin, and a third linear conductor extending in the same direction as the second linear conductor from an intermediate point of the first linear conductor as an origin; and

the second antenna element includes an L-shaped element that is formed into an L-shape by a fourth linear conductor having one end connected either directly or via a connection conductor to the second feeding portion and extending in a horizontal direction on a side of the first linear conductor on which the second linear conductor extends and a fifth linear conductor extending in a vertical direction from another end of the fourth linear conductor as an origin.

2. The glass antenna according to claim 1, wherein
at least one of the second linear conductor, the third linear conductor, and the fifth linear conductor that is connected to the signal-side feeding portion extends at a region closer toward the signal-side feeding portion with respect to at least another one of the second linear conductor, the third linear conductor, and the fifth linear conductor that is connected to the ground-side feeding portion.

3. The glass antenna according to claim 1 or 2, wherein
the fifth linear conductor extends between the second linear conductor and the third linear conductor.

4. The glass antenna according to any one of claims 1 to 3, wherein
the first feeding portion is the signal-side feeding portion and the second feeding portion is the ground-side feeding portion.

5. The glass antenna according to claim 4, wherein
the antenna conductor is a common antenna conductor configured to be used for a first frequency band and a second frequency band that is lower than the first frequency band; and
provided λ₀₁ represents a wavelength in air of a central frequency of the first frequency band, k₁ represents a shortening coefficient of wavelength by glass (where k₁ = 0.74), and λ_g1 = λ₀₁·k₁ represents a wavelength in glass, a conductor length of the third linear conductor is greater than or equal to (1/5) λ_g1.

6. The glass antenna according to claim 4, wherein
a conductor length of the third linear conductor is greater than or equal to 30 mm.

7. The glass antenna according to any one of claims 4 to 6, wherein
the antenna conductor is a common antenna conductor configured to be used for a first frequency band and a second frequency band that is lower than the first frequency band; and
provided λ₀₂ represents a wavelength in air of a central frequency of the second frequency band, k₂ represents a shortening coefficient of wavelength by glass (where k₂ = 0.54), and λ_g2 = λ₀₂· k₂ represents a wavelength in glass, a conductor length of the fifth linear conductor is greater than or equal to (1/26) λ_g2.

8. The glass antenna according to any one of claims 4 to 6, wherein
a conductor length of the fifth linear conductor is greater than or equal to 30 mm.

9. The glass antenna according to any one of claims 4 to 8, wherein
a conductor length of the second linear conductor is greater than or equal to 30 mm and less than or equal to 100 mm.

10. The glass antenna according to any one of claims 1 to 9, wherein
the antenna conductor includes a sixth linear conductor that is connected to the other end of the first linear conductor or the fourth linear conductor that is connected to the signal-side feeding portion.

11. The glass antenna according to claim 10, wherein
a conductor length of the sixth linear conductor is greater than or equal to 20 mm and less than or equal to 100 mm.

12. The glass antenna according to any one of claims 1 to 11, wherein
the antenna conductor is a common antenna conductor configured to be used for 174 to 240 MHz and 1452 to 1492 MHz.

13. A window glass for vehicle comprising the glass antenna according to any one of claims 1 to 12.

Drawing