EP3499639B1

EP3499639B1 - Glass antenna

Info

Publication number: EP3499639B1
Application number: EP18210663.3A
Authority: EP
Inventors: Kazuo Shigeta; Tatsuaki Taniguchi; Yoshiaki Hirasa; Koichi Miyake
Original assignee: Mazda Motor Corp
Current assignee: Mazda Motor Corp
Priority date: 2017-12-13
Filing date: 2018-12-06
Publication date: 2021-10-13
Anticipated expiration: 2038-12-06
Also published as: EP3499639A1; JP2019106642A; JP6540782B2

Description

TECHNICAL FIELD

The present invention relates to a glass antenna, and more particularly to a glass antenna provided to a vehicle window glass.

BACKGROUND ART

In a vehicle such as an automobile, there has been known a glass antenna having a conductor wire printed on a rear window glass. This glass antenna can be used to receive FM radio broadcasts or the like. Such a glass antenna comprises an antenna element composed of a conductor wire printed on a rear window glass, and a feeding terminal to which the antenna element is connected and which is connected to a receiver via an antenna amplifier. The feeding terminal is connected, for example, to an antenna element for receiving FM radio broadcasts and an antenna element for receiving digital radio broadcasts (DAB).
As one example, a glass antenna disclosed in JP 2015-142162A is configured to receive FM radio broadcasts and digital radio broadcasts, wherein a first element and a second element are connected to a feeding terminal connected to an antenna amplifier. The second element has an element body portion extending from the feeding terminal, and a folded-back portion folded back from an end of the element body portion and disposed along the element body portion.
EP 3 101 733 A1 provides a glass antenna arranged on a window glass for a vehicle, comprising a first antenna. The first antenna includes a first power feeding point connected to a receiver, a first element connected to the first power feeding point, and a second element connected to the first power feeding point. The second element includes a main body portion extending from the first power feeding point, and a folded portion connected to the main body portion. The folded portion is folded back from the main body portion and is arranged along the main body portion.
EP 3 101 734 A1 teaches a glass antenna arranged on a window glass for a vehicle, comprising a power feeding point connected to a receiver, a first element extending from the power feeding point. The first element includes an overlap portion arranged along a second element that is not connected to the power feeding point so as to be spaced apart from the second element with a predetermined spacing, and a non-overlap portion prevented from being arranged along the second element. Each length of the overlap portion and the non-overlap portion are adjusted so that the overlap portion is tuned to a first frequency band, and the non-overlap portion is tuned to a second frequency band.
WO 2017/208569 A1 discloses a glass antenna arranged in a vehicle window glass. This glass antenna is provided with: a power supply terminal that is connected to an antenna amplifier; a first antenna that is connected to the power supply terminal and set so as to receive high-frequency signals of a first frequency band in which the wavelength of the center frequency is a first wavelength; a coupling element that has a length set on the basis of the length obtained by multiplying 1/2 of the first wavelength by a glass reduction rate and that is connected to the power supply terminal; and a second antenna that is capacitively coupled to the coupling element and set so as to receive high-frequency signals of a second frequency band in which the wavelength of the center frequency is a second wavelength.
A dual band glass antenna for a vehicle, which includes: a feeding part; and an antenna conductor adapted to be disposed in or on a window glass for the vehicle, including: a loop element formed into a loop; a L-shaped element, including: a first antenna element, extending in a first direction from a first point of the loop element; and a second antenna element, extending in a second direction roughly perpendicular to the first direction from an end point of the first antenna element; and a connection element, connecting the feeding part with the second point of the loop element is provided by EP 2 159 872 A1 .

SUMMARY OF INVENTION

[Technical Problem]

In a case where an FM-digital radio antenna element (i.e., an antenna element having functions of both an FM antenna element for receiving FM radio broadcasts, and a digital radio antenna element for receiving digital radio broadcasts) is provided at a rear window glass of a vehicle, a radio wave received by the FM-digital radio antenna element can be transmitted from a feeding terminal connected directly to the FM-digital radio antenna element, to a receiver via an antenna amplifier.
As depicted in FIG. 5, a glass antenna 110 provided to a rear window glass 101 of a vehicle comprises an FM-digital radio antenna element 120 configured to receive FM radio broadcasts and digital radio broadcasts, and a feeding terminal 130 connected directly to the FM-digital radio antenna element 120. A radio wave received by the FM-digital radio antenna element 120 is transmitted from the feeding terminal 130 to a non-depicted receiver via an antenna connection wire 111, an antenna amplifier 112, and coaxial cable 113.
By connecting the feeding terminal directly to the FM-digital radio antenna element, it becomes possible to receive FM radio broadcasts and digital radio broadcasts with good quality, and share a single feeding terminal for both the FM radio broadcasts and the digital radio broadcasts to reduce the number of components.
However, in a case where the feeding terminal to be connected to the FM-digital radio antenna element is attached to a feeding terminal base portion of the FM-digital radio antenna element from the side of a vehicle interior, the feeding terminal base portion which is formed of an electro-conductive silver paste is exposed to the inside of the vehicle interior, and the feeding terminal is also exposed to the inside of the vehicle interior. Thus, if a passenger on a rear seat of the vehicle comes into contact with the feeding terminal, the feeding terminal is likely to be damaged.
As one measure against this problem, it is conceivable to cover the feeding terminal with a cover member from the side of the vehicle interior so as to suppress damage to the feeding terminal. However, even in this case, there still remains the possibility that the feeding terminal is damaged due to contact of a passenger on the rear seat with the feeding terminal. Moreover, the cover member can lead to increases in the number of components and an assembling process time.
It is therefore object of the present invention to provide a glass antenna having a structure in which a single feeding terminal is shared by an FM antenna element and a digital radio antenna element, and a capability of ensuring a good receiving sensitivity of the FM antenna element and the digital radio antenna element, and preventing damage to the feeding terminal.

[Solution to Technical Problem]

In order to solve the above problem, the present invention is characterized in that it has the following feature.
The present invention provides a glass antenna provided to a vehicle window glass as defined in claim 1. The glass antenna comprises: the vehicle window glass; an FM-digital radio antenna element provided at the vehicle window glass, wherein the FM-digital radio antenna element functions as an FM antenna element configured to receive a high-frequency signal in an FM broadcast band of which center-frequency wavelength is a first wavelength, and a digital radio antenna element configured to receive a high-frequency signal in a digital radio broadcast band from 170 MHz to 240 MHz of which center-frequency wavelength is a second wavelength; a first conductor wire at least partly disposed on the vehicle window glass, and formed to have a length such that the sum of a length obtained by dividing the length of the portion of the first conductor wire disposed at the vehicle window glass by a glass wavelength reduction rate of the vehicle window glass and the length of the remaining portion of the first conductor wire which is not disposed at the vehicle window glass becomes a length within a range of +/-20% with respect to the length equal to one-half of the second wavelength; a second conductor wire provided at the vehicle window glass and connected to one end of the first conductor wire, wherein the second conductor wire is formed to have a length such that a length obtained by dividing the length of the second conductor wire by the glass wavelength reduction rate becomes a length falling within a range of +/-20% with respect to the length equal to one-quarter of the second wavelength, and disposed adjacent to the FM-digital radio antenna element such that it is capacitively coupled with the FM-digital radio antenna element; and a feeding terminal connected to the first conductor wire, wherein the first conductor wire extends outward in the vehicle-width direction from the one end of the first conductor wire beyond the second conductor wire and the FM-digital radio antenna element to connect to the feeding terminal, and the feeding terminal is disposed on an outer portion of the vehicle window glass in the vehicle-width direction to be covered by a rear pillar cover.
Preferably, in the glass antenna of the present invention, the FM-digital radio antenna element is provided at each of two laterally opposite portions of the vehicle window glass in the vehicle-width direction, wherein the vehicle window glass is a rear window glass.
Preferably, the glass antenna of the present invention comprises an AM antenna element configured to receive a high-frequency signal in an AM radio broadcast band and disposed on a vehicle-width directional central portion of the vehicle window glass, wherein the AM antenna element is connected to the second conductor wire.
Further preferably, in the glass antenna of the present invention, the second conductor wire is disposed to avoid capacitive coupling with the panel member of the vehicle body.

[Effect of Invention]

The glass antenna of the present invention comprises: the vehicle window glass; an FM-digital radio antenna element functioning as both an FM antenna element configured to receive a high-frequency signal in an FM broadcast band (center-frequency wavelength: a first wavelength), and a digital radio antenna element configured to receive a high-frequency signal in a digital radio broadcast band from 170 MHz to 240 MHz (center-frequency wavelength: a second wavelength); a first conductor wire at least partly disposed on a vehicle window glass, and formed to have a length such that the sum of a length obtained by dividing the length of the portion of the first conductor wire disposed at the vehicle window glass by a glass wavelength reduction rate of the vehicle window glass and the length of the remaining portion of the first conductor wire which is not disposed at the vehicle window glass becomes a length within a range of +/-20% with respect to the length equal to one-half of the second wavelength; a second conductor wire provided at the vehicle window glass and connected to one end of the first conductor wire, wherein the second conductor wire is formed to have a length such that a length obtained by dividing the length of the second conductor wire by the glass wavelength reduction rate becomes a length within a range of +/-20% with respect to the length equal to one-quarter of the second wavelength, and disposed adjacent to the FM-digital radio antenna element such that it is capacitively coupled with the FM-digital radio antenna element; and a feeding terminal connected to the first conductor wire, wherein the first conductor wire extends outward in the vehicle-width direction from the one end of the first conductor wire beyond the second conductor wire and the FM-digital radio antenna element to connect to the feeding terminal, and the feeding terminal is disposed on an outer portion of the vehicle window glass in the vehicle-width direction to be covered by a rear pillar cover.
According to this feature, the feeding terminal can be covered by the rear pillar cover, so that it becomes free from being exposed to the inside of a vehicle interior of a vehicle. Thus, in the present invention, it becomes possible to prevent a passenger on a rear seat of the vehicle from coming into contact with the feeding terminal and thus avoid damage to the feeding terminal, without additionally providing a cover member for covering the feeding terminal.
The first conductor wire connected to the feeding terminal is capacitively coupled to the FM-digital radio antenna element through the second conductor wire, so that, regarding an impedance in the FM radio broadcast band, an inductive reactance caused by an inductance arising based on a difference between the length of the first conductor wire and a length equal to one-quarter of the first wavelength can be cancelled out by a capacitive reactance caused by a capacitance of the capacitive coupling between the FM-digital radio antenna element and the second conductor wire. Thus, in the present invention, it becomes possible to suppress deterioration in receiving sensitivity as the FM antenna element in the FM-digital radio antenna element and thus ensure a good receiving sensitivity of the FM antenna element.
Further, the second conductor wire connected to the first conductor wire is formed to have a length set based on a length equal to one-quarter of the second wavelength, and is disposed adjacent to the FM-digital radio antenna element. Thus, the glass antenna of the present invention can be deemed to have a configuration in which the one end of the first conductor wire is connected directly to the FM-digital radio antenna element. Further, the first conductor wire is formed to have a length set based on a length equal to one-half of the second wavelength, so that it is possible to approximately equalize the receiving sensitivity of the digital radio antenna element at one end and the other end of the first conductor wire. Thus, in the present invention, it becomes possible to suppress deterioration in receiving sensitivity of the FM-digital radio antenna element as the digital radio antenna element, and thus ensure a good receiving sensitivity of the digital radio antenna element.
Therefore, the glass antenna of the present invention can ensure a good receiving sensitivity of the FM antenna element and the digital radio antenna element while enabling the FM antenna element and the digital radio antenna element to share the feeding terminal, and prevent damage to the feeding terminal.
According to the present invention, the first conductor wire is configured such that the portion thereof provided at the vehicle window glass has a length obtained by subtracting a length of the remaining portion which is not provided at the vehicle window glass, from a length falling within the range of +/-20% with respect to the length equal to one-half of the second wavelength to calculate a value, and multiplying the calculated value by the glass wavelength reduction rate, and the second conductor wire is configured such that the portion thereof provided at the vehicle window glass has a length obtained by multiplying a length falling within the range of +/-20% with respect to the length equal to one-quarter of the second wavelength, by the glass wavelength reduction rate. According to this feature, it becomes possible to specifically attain the above advantageous effect.
In another specific embodiment of the present invention, the FM-digital radio antenna element is provided at each of two laterally opposite portions of the vehicle window glass in the vehicle-width direction, and wherein the vehicle window glass is a rear window glass. According to this feature, the FM-digital radio antenna element can be formed in a diversity system, and thus it becomes possible to improve receiving sensitivities of the FM antenna element and the digital radio antenna element.
In another specific embodiment of the present invention, the glass antenna comprises an AM antenna element configured to receive a high-frequency signal in an AM radio broadcast band and disposed on a vehicle-width directional central portion of the vehicle window glass, wherein the AM antenna element is connected to the second conductor wire. According to this feature, it becomes possible to enable the AM antenna element to additionally share the feeding terminal of the FM antenna element and the digital radio antenna element.
In yet another specific embodiment of the present invention, in the glass antenna, the second conductor wire is disposed to avoid capacitive coupling with the panel member of the vehicle body. According to this feature, the present invention can maintain a good receiving performance in a certain wide frequency range, for example in DAB and FM broadcast bands.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram depicting the configuration of a glass antenna according to one embodiment of the present invention.
FIG. 2 is an enlarged diagram of a main part of the glass antenna depicted in FIG. 1.
FIG. 3 is a graph indicating a frequency characteristic of the glass antenna in a digital radio broadcast band.
FIG. 4 is a graph indicating a frequency characteristic of the glass antenna in an FM radio broadcast band.
FIG. 5 is a diagram depicting the configuration of a conventional glass antenna.

DESCRIPTION OF EMBODIMENTS

With reference to the accompanying drawings, the present invention will now be described based on an embodiment thereof.
FIG. 1 depicts the configuration of a glass antenna according to one embodiment of the present invention. As depicted in FIG. 1, the glass antenna 10 according to this embodiment is provided at a rear window glass 1 among various vehicle window glasses. FIG. 1 depicts a state of the glass antenna 10 when viewed from the side of a vehicle interior of a vehicle. A peripheral portion of the rear window glass (window pane) 1 is attached to a flange of a panel member of a vehicle body (not depicted) from the side of a rear end of the vehicle body.
The glass antenna 10 is provided at least at an upper side of and on one of the laterally opposite sides in the vehicle-width direction (on a vehicle-left side) of the rear window glass 1. The glass antenna 10 comprises: an FM-digital radio antenna element 20 functioning as both an FM antenna element and a digital radio antenna element; a first conductor wire 30 at least partly provided at the rear window glass 1, correspondingly to the FM-digital radio antenna element 20; a second conductor wire 40 provided at the rear window glass 1 and connected to a first one of opposite ends of the first conductor wire 30, wherein the second conductor wire 40 is disposed adjacent to the FM-digital radio antenna element 20 such that it is capacitively coupled with the FM-digital radio antenna element 20; and a feeding terminal 45 connected to the other, second, end of the first conductor wire 30. On the rear window glass 1, each of the FM-digital radio antenna element 20, the first conductor wire 30 and the second conductor wire 40 is formed of a conductor wire composed of an electroconductive silver paste printed on the rear window glass 1.
FIG. 2 is an enlarged diagram of a main part of the glass antenna depicted in FIG. 1. The FM-digital radio antenna element 20 is used as both an FM antenna element configured to receive a high-frequency signal in an FM broadcast band (in this embodiment, the frequency of this signal is in the range of 88 to 108 MHz, wherein a center frequency thereof is 98MHz) (a wavelength at this center frequency (center-frequency wavelength) will be referred to as "first wavelength"), and a digital radio antenna element configured to receive a high-frequency signal in a digital radio broadcast band (according to the invention, the frequency of this signal is in the range of 170 to 240 MHz, wherein a center frequency thereof is 205MHz) (a wavelength at this center frequency (center-frequency wavelength) will be referred to as "second wavelength").
As depicted in FIG. 2, the FM-digital radio antenna element 20 has: a plurality of horizontal parts extending horizontally in a vehicle-width direction in mutually parallel relation (specifically, a first horizontal part 21, a second horizontal part 22, a third horizontal part 23, a fourth horizontal part 24, and a fifth horizontal part 25 which are arranged in this order along a downward direction at intervals of a given distance); and a first vertical part 26 and a second vertical part 27 each extending vertically (i.e., in an upward-downward direction or a vehicle-height direction), while connecting a respective one of a group of vehicle-left ends of and a group of vehicle-right ends of the plurality of horizontal parts 21, 22, 23, 24, 25.
The length L1 of each of the first horizontal part 21, the second horizontal part 22, the third horizontal part 23, the fourth horizontal part 24 and the fifth horizontal part 25 is set to 150 mm. Each of a distance L2 between the first horizontal part 21 and the second horizontal part 22, a distance L3 between the second horizontal part 22 and the third horizontal part 23, a distance L4 between the third horizontal part 23 and the fourth horizontal part 24 and a distance L5 between the fourth horizontal part 24 and the fifth horizontal part 25 is set to 30 mm. The length L6 of each of the first vertical part 26 and the second vertical part 27 is set to 120 mm.
In FIGS. 1 and 2, a rear pillar cover 2 for covering an outer portion of the rear window glass 1 in the vehicle-width direction from the side of the vehicle interior, and a roof lining 3 for covering a vehicle-height directional upper portion of the rear window glass 1 from the side of the vehicle interior are indicated by two-dot chain lines. The feeding terminal 45 for the FM-digital radio antenna element 20 is attached to the rear window glass 1 at a position on the side of the vehicle interior, such that it is disposed on the outer portion of the rear window glass 1 in the vehicle-width direction to be covered by the rear pillar cover 2. More specifically, the feeding terminal 45 is disposed on the center side of the rear window glass 1 in the vehicle-width direction, with respect to an inner edge of the flange of the panel member of the vehicle body.
The second end of the first conductor wire 30 is provided with a feeding terminal base portion 30a exposed to the inside of the vehicle interior. The feeding terminal 45 is attached to the feeding terminal base portion 30a from the side of the vehicle interior. The feeding terminal base portion 30a is also formed of an electroconductive silver paste printed on the rear window glass 1. The feeding terminal 45 is provided at a position overlapping the fourth horizontal part 24 of the FM-digital radio antenna element 20 in the upward-downward direction.
As above, the feeding terminal 45 can be disposed on the vehicle-width directional outer portion of the rear window glass 1 in a state in which it is covered by the rear pillar cover 2, so that the feeding terminal 45 is not exposed to the inside of the vehicle interior. This makes it possible to prevent damage to the feeding terminal 45 due to contact of a passenger on a rear seat of the vehicle with the feeding terminal 45, without additionally providing a cover member covering the feeding terminal 45.
In this embodiment, after attaching the feeding terminal 45 to the rear window glass 1 to which the roof lining 3 has been attached, the rear pillar 2 can be attached to the rear window glass 1, so that it is possible to prevent damage to the feeding terminal 45 in a relatively easy manner.
An antenna connection wire 11 functions as part of the first conductor wire 30 to connect the feeding terminal 45 and an antenna amplifier 12 together, although the antenna connection wire 11 is not provided at the rear window glass 1. The antenna amplifier 12 is connected to a receiver (not depicted) via a coaxial cable 13. A radio wave received by the FM-digital radio antenna element 20 is input to the antenna amplifier 12 via the feeding terminals 45, and, after being amplified by the antenna amplifier 12, transmitted to the receiver. The antenna amplifier 12 is grounded and fixed to a rear pillar of the vehicle.
The first conductor wire 30 provided at the rear window glass 1 is disposed such that the first end thereof is located at a position spaced apart upwardly from an upper end of the second vertical part 27 of the FM-digital radio antenna element 20 by a given distance, and the second end thereof is connected to the feeding terminal 45. In the glass antenna 10, a distance L7 between the first end of the first conductor wire 30 and the upper end of the second vertical part 27 of the FM-digital radio antenna element 20 is set to 15 mm.
The first conductor wire 30 is formed to have a length set based on a length equal to one-half of the wavelength at the center frequency of the digital radio broadcast band (second wavelength). The first conductor wire 30 has a first portion disposed on the rear window glass 1, and a second portion (the antenna connection wire 11). The length of the first conductor wire 30 is set such that the sum of a length obtained by dividing the length of the first portion disposed on the rear window glass 1 by a glass wavelength reduction rate α of the rear window glass 1, and the length of the second portion (antenna connection wire 11), becomes a length falling within a given range with respect to the length equal to one-half of the second wavelength. With a view to ensuring ease of assembling, the length of the antenna connection wire 11 is set to about 150 mm. The glass wavelength reduction rate α of the rear window glass 1 is set to 0.7.
Specifically, the length of the first conductor wire 30 is set such that it falls within a given range (e.g., within ± 20%) with respect to the length equal to one-half of the wavelength at the center frequency of the digital radio broadcast band of 170 to 240 MHz (second wavelength). For example, the given range is set such that an average receiving sensitivity equal to or greater than a given receiving sensitivity (e.g., a given receiving sensitivity of around - 10 dB relative to a receiving sensitivity of a dipole antenna) is obtained in the frequency characteristic in the digital radio broadcast band of 170 to 240 MHz
Further, the first conductor wire 30 is formed to have a length around or close to a length equal to one-quarter of the wavelength (first wavelength) at the center frequency of the FM radio broadcast band of 88 to 108 MHz. The length of the first conductor wire 30 is set such that the sum of a length obtained by dividing the length of the first portion disposed on the rear window glass 1 by the glass wavelength reduction rate α of the rear window glass 1, and the length of the antenna connection wire 11, becomes a length around or close to the length equal to one-quarter of the first wavelength.
The first portion of the first conductor wire 30 disposed on the rear window glass 1 has: a first vertical part 31 extending upwardly from the first end of the first conductor wire 30; a first horizontal part 32 extending from an upper end of the first vertical part 31 toward the vehicle-left side in an approximately horizontal direction; and a second vertical part 33 extending downwardly from a vehicle-left end of the first horizontal part 32 and connected to the feeding terminal 45.
Thus, the sum of a length obtained by dividing the sum of respective lengths of the first vertical part 31, the first horizontal part 32 and the second vertical part 33 by the glass wavelength reduction rate α of the rear window glass 1, and the length of the antenna connection wire 11, is a length falling within the given range with respect to the length equal to one-half of the second wavelength. The first portion disposed on the vehicle window glass 1 has a length obtained by subtracting the length of the second portion 11 which is not provided at the vehicle window glass 1, from the length falling within the given range with respect to the length equal to one-half of the second wavelength to obtain a calculated value, and multiplying the calculated value by the glass wavelength reduction rate α.
In the glass antenna 10, the length L8 of the first vertical part 31 is set to 15 mm, and the sum of respective lengths of the first horizontal part 32 and the second vertical part 33 is set to 340 mm. The portion of the first conductor wire 30 disposed on the rear window glass 1 is set to 355 mm. The length of the antenna connection wire 11 is set to about 150 mm.
The second conductor wire 40 is disposed adjacent to and apart by a given distance from the FM-digital radio antenna element 20, such that it is capacitively coupled with the FM-digital radio antenna element 20. The second conductor wire 40 has: a first horizontal part 41 extending from the first end P1 of the first conductor wire 30 toward the vehicle-left side horizontally in parallel relation to the first horizontal part 21 of the FM-digital radio antenna element 20; a first vertical part 42 extending downwardly from a vehicle-left end of the first horizontal part 41; and a second horizontal part 43 extending from a lower end of the first vertical part 42 toward a vehicle-right side horizontally in parallel relation to the first horizontal part 21 of the FM-digital radio antenna element 20.
In the glass antenna 10, a distance L9 between the second horizontal part 43 of the second conductor wire 40 and the first horizontal part 21 of the FM-digital radio antenna element 20, and a distance L10 between the first horizontal part 41 and the first horizontal part 21, are set, respectively, to 5 mm and 15 mm. A distance L11 between the first horizontal part 41 and the inner edge of the flange 4 of the panel member (formed of a metal such as a steel sheet) of the vehicle body (see the dotted line in FIG. 2) is set to 20 mm. That is, the second conductor wire 40 is disposed to avoid capacitive coupling with the panel member of the vehicle body.
The second conductor wire 40 is formed to have a length set based on a length equal to one-quarter of the wavelength (second wavelength) at the center frequency of the digital radio broadcast band of 170 to 240 MHz. The length of the second conductor wire 40 is set such that a length obtained by dividing the length of the second conductor wire 40 disposed on the rear window glass 1 by the glass wavelength reduction rate α of the rear window glass 1 becomes a length falling within a given range with respect to the length equal to one-quarter of the second wavelength.
Specifically, in the second conductor wire 40, the length obtained by dividing the length of the second conductor wire 40 disposed on the rear window glass 1 by the glass wavelength reduction rate α of the rear window glass 1 is set such that it falls within a given range (e.g., within ± 20%) with respect to the length equal to one-quarter of the wavelength (second wavelength) at the center frequency of the digital radio broadcast band of 170 to 240 MHz. In the glass antenna 10, the length L12 of each of the first horizontal part 41 and the second horizontal part 43 is set to 150 mm, and the length L13 of the first vertical part 42 is set to 10 mm. That is, the length of the second conductor wire 40 disposed on the rear window glass 1 is set to 310 mm. For example, the given range is set such that an average receiving sensitivity equal to or greater than a given receiving sensitivity (e.g., a given receiving sensitivity of around - 10 dB relative to a receiving sensitivity of a dipole antenna) is obtained in the frequency characteristic in the digital radio broadcast band of 170 to 240 MHz.
Frequency characteristics of the glass antenna 10 according to this embodiment measured in the digital radio broadcast band and the FM radio broadcast band were as follows.
FIG. 3 is a graph indicating the frequency characteristic of the glass antenna in the digital radio broadcast band. In FIG. 3, the horizontal axis represents the frequency in the digital radio broadcast band, and the vertical axis represents the receiving sensitivity to the frequency in the digital radio broadcast band. In regard to the receiving sensitivity on the vertical axis, a smaller minus value (i.e., a larger receiving sensitivity) means a better receiving sensitivity. This receiving sensitivity indicates a receiving sensitivity before the amplification by the antenna amplifier 12, and is expressed relative to a receiving sensitivity of a dipole antenna. Although FIG. 3 indicates a receiving sensitivity measured via the feeding terminal 45 located on the vehicle-left side, the same characteristic could be obtained in regard to a receiving sensitivity measured via the aftermentioned feeding terminal 75 located on the vehicle-right side exhibited.
As indicated in FIG. 3, in the glass antenna 10, receiving sensitivities at frequencies around 174 to 180 MHz and around 194 to 202 MHz are less than those at other frequencies. However, an average of receiving sensitivities at all frequencies in the digital radio broadcast band is equal to or greater than the given receiving sensitivity of around - 10 dB, which shows that a good receiving sensitivity is obtained.
FIG. 4 is a graph indicating the frequency characteristic of the glass antenna in the FM radio broadcast band. In FIG. 4, the horizontal axis represents the frequency in the FM radio broadcast band, and the vertical axis represents the receiving sensitivity to the frequency in the FM radio broadcast band. In regard to the receiving sensitivity on the vertical axis, a smaller minus value (i.e., a larger receiving sensitivity) means a better receiving sensitivity. This receiving sensitivity indicates a receiving sensitivity before the amplification by the antenna amplifier 12, and is expressed relative to a receiving sensitivity of a dipole antenna. Although FIG. 4 indicates a receiving sensitivity measured via the feeding terminal 45 located on the vehicle-left side, the same characteristic could be obtained in regard to a receiving sensitivity measured via the aftermentioned feeding terminal 75 located on the vehicle-right side exhibited.
As indicated in FIG. 4, in the glass antenna 10, receiving sensitivities at frequencies around 88 to 93 MHz are less than those at other frequencies. However, an average of receiving sensitivities at all frequencies in the FM radio broadcast band is equal to or greater than the given receiving sensitivity of around - 10 dB, which shows that a good receiving sensitivity is obtained.
Here, receiving performance of the glass antenna in the digital radio broadcast band and the FM radio broadcast band will be described.
As depicted in FIG. 2, the second conductor wire 40 connected to the first end P1 of the first conductor wire 30 is formed to have a length set based on the length equal to one-quarter of the wavelength (second wavelength) at the center frequency of the digital radio broadcast band, and disposed adjacent to the FM-digital radio antenna element 20. Thus, the glass antenna 10 can be deemed to have a configuration in which, in the digital radio broadcast band, the first end P1 of the first conductor wire 30 is connected directly to the FM-digital radio antenna element 20.
Further, the first conductor wire 30 is formed to have a length set based on the length equal to one-half of the wavelength (second wavelength) at the center frequency of the digital radio broadcast band, so that it is possible to approximately equalize the receiving sensitivity of the digital radio antenna element at the first end P1 and the second end P2 of the first conductor wire 30.
Therefore, the glass antenna 10 can suppress a situation where the receiving sensitivity of the FM-digital radio antenna element 20 serving as the digital radio antenna element deteriorates in the digital radio broadcast band, and thus ensure a good receiving sensitivity of the digital radio antenna element in the digital radio broadcast band.
In the glass antenna 10, the first conductor wire 30 connected to the feeding terminal 45 is also formed to have a length around the length equal to one-quarter of the wavelength (first wavelength) at the center frequency of the FM radio broadcast band, and the first end P1 of the first conductor wire 30 is capacitively coupled to the FM-digital radio antenna element 20 through the second conductor wire 40.
According to this configuration, regarding an impedance in the FM radio broadcast band, an inductive reactance caused by an inductance arising based on a difference between the length of the first conductor wire 30 and a length equal to one-quarter of the first wavelength can be cancelled out by a capacitive reactance caused by a capacitance of the capacitive coupling between the FM-digital radio antenna element 20 and the second conductor wire 40.
Therefore, the glass antenna 10 can suppress a situation where the receiving sensitivity of the FM-digital radio antenna element 20 serving as the FM antenna element deteriorates in the FM radio broadcast band, and thus ensure a good receiving sensitivity of the FM antenna element in the FM radio broadcast band.
As depicted in FIG. 1, the glass antenna 10 further comprises: an FM-digital radio antenna element 50 provided at the upper side of and on the other side (vehicle-right side) of the rear window glass 1, wherein the FM-digital radio antenna element 50 functions as both an FM antenna element and a digital radio antenna element; a first conductor wire 60 at least partly provided at the rear window glass 1, correspondingly to the FM-digital radio antenna element 60; a second conductor wire 70 provided at the rear window glass 1 and connected to a first one of opposite ends of the first conductor wire 60, wherein the second conductor wire 70 is disposed adjacent to the FM-digital radio antenna element 50 such that it is capacitively coupled with the FM-digital radio antenna element 50; and a feeding terminal 75 connected to the other, second, end of the first conductor wire 60. On the rear window glass 1, each of the FM-digital radio antenna element 50, the first conductor wire 60 and the second conductor wire 70 is formed of a conductor wire composed of an electroconductive silver paste printed on the rear window glass 1.
The FM-digital radio antenna element 50 and the FM-digital radio antenna element 20 are formed on the rear window glass 1 such that they are arranged along the vehicle-width direction in bilaterally symmetric relation. The FM-digital radio antenna element 50 is used as both an FM antenna element configured to receive a high-frequency signal in the FM broadcast band (of which center-frequency wavelength is a first wavelength), and a digital radio antenna element configured to receive a high-frequency signal in a digital radio broadcast band (of which center-frequency wavelength is a second wavelength).
The FM-digital radio antenna element 50 has: a plurality of horizontal parts extending horizontally in the vehicle-width direction in mutually parallel relation (specifically, a first horizontal part 51, a second horizontal part, a third horizontal part, a fourth horizontal part and a fifth horizontal part which are arranged in this order along a downward direction at intervals of a given distance); and a first vertical part 56 and a second vertical part 57 each extending vertically (i.e., in the upward-downward direction or the vehicle-height direction), while connecting a respective one of a group of vehicle-left ends of and a group of vehicle-right ends of the plurality of horizontal parts 51.
The feeding terminal 75 for the FM-digital radio antenna element 50 is formed in the same manner as that in the feeding terminal 45 for the FM-digital radio antenna element 20. More specifically, the feeding terminal 75 is disposed on the vehicle-width directional outer portion of the rear window glass 1, and attached to the rear window glass 1 at a position on the side of the vehicle interior in a state in which it is covered by the rear pillar cover 2. Further, the feeding terminal 75 is disposed on the side of the vehicle-width directional center of the rear window glass 1, with respect to the inner edge of the flange of the panel member of the vehicle body to which the rear window glass 1 is attached.
The feeding terminal 75 is connected to an antenna amplifier 15 via an antenna connection wire 14 which is not disposed on the rear window glass 1 and functions as part of the first conductor wire 60. The antenna amplifier 15 is connected to a receiver (not depicted) via a coaxial cable 16. A radio wave received by the FM-digital radio antenna element 50 is input to the antenna amplifier 15 via the feeding terminals 75, and, after being amplified by the antenna amplifier 15, transmitted to the receiver. The antenna amplifier 15 is grounded and fixed to the rear pillar of the vehicle.
The first conductor wire 60 provided at the rear window glass 1 is formed such that the first conductor wire 60 and the first conductor wire 30 are arranged along the vehicle-width direction in approximately symmetric relation, and disposed such that the first end thereof is located at a position spaced apart upwardly from the first horizontal part 51 by a given distance in the vicinity of an upper end of the second vertical part 57 of the FM-digital radio antenna element 50, and the second end thereof is connected to the feeding terminal 75. In the glass antenna 10, a distance between the first end of the first conductor wire 60 and the first horizontal part 51 of the FM-digital radio antenna element 50 is set to 15 mm.
The first conductor wire 60 is formed to have a length set based on the length equal to one-half of the wavelength (second wavelength) at the center frequency of the digital radio broadcast band. The length of the first conductor wire 60 is set such that the sum of a length obtained by dividing the length of a portion thereof disposed on the rear window glass 1 by the glass wavelength reduction rate α of the rear window glass 1, and the length of the antenna connection wire 14, becomes a length falling within a given range (e.g., within ± 20%) with respect to the length equal to one-half of the second wavelength. With a view to ensuring ease of assembling, the length of the antenna connection wire 14 is set to about 150 mm.
Further, the first conductor wire 60 is formed to have a length around a length equal to one-quarter of the wavelength (first wavelength) at the center frequency of the FM radio broadcast band of 88 to 108 MHz. The length of the first conductor wire 60 is set such that the sum of a length obtained by dividing the length of the portion disposed on the rear window glass 1 by the glass wavelength reduction rate α of the rear window glass 1, and the length of the antenna connection wire 14, becomes a length around the length equal to one-quarter of the first wavelength.
The portion of the first conductor wire 60 disposed on the rear window glass 1 has: a first vertical part extending upwardly from the first end of the first conductor wire 60; a first horizontal part extending from an upper end of the first vertical part toward the vehicle-right side in an approximately horizontal direction; and a second vertical part extending downwardly from a vehicle-right end of the first horizontal part and connected to the feeding terminal 75.
Thus, the sum of a length obtained by dividing the sum of respective lengths of the first vertical part, the first horizontal part and the second vertical part by the glass wavelength reduction rate α of the rear window glass 1, and the length of the antenna connection wire 14, is a length falling within the given range with respect to the length equal to one-half of the second wavelength. The portion disposed on the vehicle window glass 1 has a length obtained by subtracting the length of the portion 14 which is not provided at the vehicle window glass 1, from the length falling within the given range with respect to the length equal to one-half of the second wavelength, and multiplying a resulting value by the glass wavelength reduction rate α.
In the first conductor wire 60, the length of the first vertical part is set to 15 mm, and the sum of respective lengths of the first horizontal part and the second vertical part is set to 340 mm. The portion of the first conductor wire 60 disposed on the rear window glass 1 is set to 355 mm. The length of the antenna connection wire 14 is set to about 150 mm.
The second conductor wire 70 is disposed adjacent to and apart by a given distance from the FM-digital radio antenna element 50, such that it is capacitively coupled with the FM-digital radio antenna element 50. The second conductor wire 70 has: a first horizontal part extending from the first end of the first conductor wire 60 toward the vehicle-right side horizontally in parallel relation to the first horizontal part 51 of the FM-digital radio antenna element 50; a first vertical part extending downwardly from a vehicle-right end of the first horizontal part; and a second horizontal part extending from a lower end of the first vertical part toward the vehicle-left side horizontally in parallel relation to the first horizontal part 51 of the FM-digital radio antenna element 50.
In the glass antenna 10, a distance between the second horizontal part of the second conductor wire 70 and the first horizontal part 51 of the FM-digital radio antenna element 50, and a distance between the first horizontal part of the second conductor wire 70 and the first horizontal part 51, are set, respectively, to 5 mm and 15 mm. A distance between the first horizontal part and the inner edge of the flange of the panel member (formed of a metal such as a steel sheet) of the vehicle body is set to 20 mm. That is, the second conductor wire 70 is disposed to avoid capacitive coupling with the panel member of the vehicle body.
The second conductor wire 70 is formed to have a length set based on a length equal to one-quarter of the wavelength (second wavelength) at the center frequency of the digital radio broadcast band of 170 to 240 MHz. The length of the second conductor wire 70 is set such that a length obtained by dividing the length of the second conductor wire 70 disposed on the rear window glass 1 by the glass wavelength reduction rate α of the rear window glass 1 becomes a length falling within a given range with respect to the length equal to one-quarter of the second wavelength.
Specifically, in the second conductor wire 70, the length obtained by dividing the length of the second conductor wire 70 disposed on the rear window glass 1 by the glass wavelength reduction rate α of the rear window glass 1 is set such that it falls within a given range (e.g., within ± 20%) with respect to the length equal to one-quarter of the wavelength (second wavelength) at the center frequency of the digital radio broadcast band of 170 to 240 MHz. In the glass antenna 10, lengths of the first horizontal part and the second horizontal part are set, respectively, to 140 mm and 150 mm, and the length of the first vertical part is set to 10 mm. That is, the length of the second conductor wire 70 disposed on the rear window glass 1 is set to 300 mm. For example, the given range is set such that an average receiving sensitivity equal to or greater than a given receiving sensitivity (e.g., a given receiving sensitivity of around - 10 dB relative to a receiving sensitivity of a dipole antenna) is obtained in the frequency characteristic in the digital radio broadcast band of 170 to 240 MHz.
Thus, the FM-digital radio antenna element 50 can also suppress deterioration in receiving sensitivity of the FM-digital radio antenna element 50 as the FM antenna element and the digital radio antenna element, and thus ensure a good receiving sensitivity of the FM-digital radio antenna element 50 in the FM radio broadcast band and the digital radio broadcast band.
As above, the glass antenna 10 is configured such that the FM-digital radio antenna elements 20, 50 are provided, respectively, on the vehicle-width directional opposite lateral portions of the rear window glass 1, to form a diversity system, so that it is possible to improve respective receiving sensitivities of the FM antenna element and the digital radio antenna element.
An AM antenna element 80 configured to receive a high-frequency signal in an AM radio broadcast band is disposed on a vehicle-width directional central portion of the rear window glass 1, and connected to the second conductor wire 70 disposed adjacent to the FM-digital radio antenna element 50 located on the vehicle-right side.
Specifically, the AM antenna element 80 is configured to receive AM radio broadcasts in an AM radio broadcast band of 500 to 1700 kHz. The AM antenna element 80 has: a plurality of horizontal parts 81 extending horizontally in the vehicle-width direction in mutually parallel relation (specifically, a first horizontal part 81, a second horizontal part, a third horizontal part, a fourth horizontal part, a fifth horizontal part and a sixth horizontal part which are arranged in this order along a downward direction at intervals of a given distance); a first vertical part 82 extending vertically (i.e., in the upward-downward direction or the vehicle-height direction), while connecting vehicle-left ends of the plurality of horizontal parts 81; and a second vertical part 83 extending downwardly from a vehicle-right end of the first horizontal part 81 and connected to a vehicle-left end of the second horizontal part of the second conductor wire 70.
In the glass antenna 10, the distance between any adjacent two of the plurality of horizontal parts 81 is set to 30 mm, and a distance between each of the vehicle-left ends of the second to sixth horizontal parts of the AM antenna element 80 and the FM-digital radio antenna element 20 and a distance between each of vehicle-right ends of the second to sixth horizontal parts of the AM antenna element 80 and the FM-digital radio antenna element 50 are set, respectively, to 50 mm and 60 mm.
The AM antenna element 80 is also formed of an electroconductive silver paste printed on the rear window glass 1.
In the glass antenna 10, a radio wave received by the AM antenna element 80 can be transmitted to the receiver via the feeding terminals 75 through amplification by the antenna amplifier 15.
As above, the AM antenna element 80 provided at the vehicle-width directional central portion of the rear window glass 1 is configured to receive a high-frequency signal in the AM radio broadcast band, and connected to the second conductor wire 70, so that it is possible to share the feeding terminal 75 with the FM antenna element and the digital radio antenna element.
The rear window glass 1 is further provided with a defogger 90. The defogger 90 is disposed over the range from one of the vehicle-width directional opposite sides to the other side of the rear window glass 1. The FM-digital radio antenna elements 20, 50, the first conductor wires 30, 60, the second conductor wires 40, 70 and the AM antenna element 80 are disposed just above the defogger 90.
The defogger 90 comprises a plurality of heating wires 91 extending over the range from the vehicle-left side to the vehicle-right side of the rear window glass 1 in approximately parallel relation in a bilaterally symmetric manner; a pair of right and left bus bars 92 each extending in the upward-downward direction, while connecting a respective one of two groups of vehicle-left ends and vehicle-right end of the plurality of heating wires 91. The defoggers 90 is configured to defog the rear window glass 1 in response to supply of current from a power source (not depicted) to the plurality of heating wires 91 via the bus bars 92. It should be noted that FIG. 1 depicts only the uppermost and lowermost heating wires among the plurality of heating wires 91.
The defogger 90 further comprises a plurality of conductor wires 93 each extending from the uppermost heating wire among the plurality of heating wires 91 toward the remaining downward-side heating wires while intersecting them. In the glass antenna 10, three conductor wires 93a, 93b, 93c are provided, respectively, on the vehicle-left side, on the vehicle-right side, and at the vehicle-width directional center.
Each of the conductor wires 93a, 93b is formed to extend between the uppermost heating wire 91 and the lowermost heating wire 91. The conductor wire 93c is formed to extend from the uppermost heating wire 91 to a lower end thereof located below the lowermost heating wire 91, and further extend from the lower end toward both the vehicle-left side and the vehicle-right side.
The defogger 90 is disposed just below and in adjacent relation to the FM-digital radio antenna elements 20, 50, so that it can also be used as an antenna element for assisting the FM antenna element in each of the FM-digital radio antenna elements 20, 50, so as to further improve the receiving sensitivity of the FM antenna element.
Each of the heating wires 91 and the conductor wires 93 is formed of an electroconductive silver paste printed on the rear window glass 1.
As above, the glass antenna 10 according to the above embodiment comprises: an FM-digital radio antenna element 20 disposed on a vehicle window glass 1 and functioning as an FM antenna element and a digital radio antenna element each configured to receive a respective one of a high-frequency signal in an FM broadcast band of which center-frequency wavelength is a first wavelength and a high-frequency signal in a digital radio broadcast band of which center-frequency wavelength is a second wavelength; a first conductor wire 30 at least partly disposed on the vehicle window glass 1 and formed to have a length set based on a length equal to one-half of the second wavelength; a second conductor wire 40 provided at the vehicle window glass 1 and connected to one end of the first conductor wire 30, wherein the second conductor wire is formed to have a length set based on a length equal to one-quarter of the second wavelength, and disposed adjacent to the FM-digital radio antenna element 20 such that it is capacitively coupled with the FM-digital radio antenna element 20; and a feeding terminal 45 connected to the other end of the first conductor wire 30, wherein the feeding terminal 45 is disposed on a vehicle-width directional outer portion of the vehicle window glass 1 to be covered by a rear pillar cover 2.
According to this configuration, the feeding terminal 45 can be covered by the rear pillar cover 2, so that it becomes free from being exposed to the inside of a vehicle interior of a vehicle. Thus, in the above embodiment, it becomes possible to prevent a passenger on a rear seat of the vehicle from coming into contact with the feeding terminal 45 and thus avoid damage to the feeding terminal 45, without additionally providing a cover member for covering the feeding terminal 45.
The first conductor wire 30 connected to the feeding terminal 45 is capacitively coupled to the FM-digital radio antenna element 20 through the second conductor wire 40, so that, regarding an impedance in the FM radio broadcast band, an inductive reactance caused by an inductance arising based on a difference between the length of the first conductor wire 30 and a length equal to one-quarter of the first wavelength can be cancelled out by a capacitive reactance caused by a capacitance of the capacitive coupling between the FM-digital radio antenna element 20 and the second conductor wire 40. Thus, in the above embodiment, it becomes possible to suppress deterioration in receiving sensitivity as the FM antenna element in the FM-digital radio antenna element 20 and thus ensure a good receiving sensitivity of the FM antenna element.
Further, the second conductor wire 40 connected to the first conductor wire 30 is formed to have a length set based on a length equal to one-quarter of the second wavelength, and is disposed adjacent to the FM-digital radio antenna element 20. Thus, the glass antenna according to the above embodiment can be deemed to have a configuration in which the one end of the first conductor wire 30 is connected directly to the FM-digital radio antenna element 20. Further, the first conductor wire 30 is formed to have a length set based on a length equal to one-half of the second wavelength, so that it is possible to approximately equalize the receiving sensitivity of the digital radio antenna element at one end P1 and the other end P2 of the first conductor wire 30. Thus, in the above embodiment, it becomes possible to suppress deterioration in receiving sensitivity of the FM-digital radio antenna element 20 as the digital radio antenna element, and thus ensure a good receiving sensitivity of the digital radio antenna element.
Therefore, the glass antenna according to the above embodiment can ensure a good receiving sensitivity of the FM antenna element and the digital radio antenna element, while enabling the FM antenna element and the digital radio antenna element to share the feeding terminal 45, and prevent damage to the feeding terminal 45.
Although the glass antenna 10 is provided with the two FM-digital radio antenna elements 20, 50, the FM-digital radio antenna element 50 may be omitted. Further, in the glass antenna 10, the AM antenna 80 may be omitted.
It should be noted that the present invention is not limited to the exemplified embodiment, but various modifications and design changes may be made therein without departing from the scope of the present invention as set forth in the appended claims.

INDUSTRIAL APPLICABILITY

As described above, the present invention makes it possible to ensure a good receiving sensitivity of an FM antenna element and a digital radio antenna element, while enabling the FM antenna element and the digital radio antenna element to share a feeding terminal, and prevent damage to the feeding terminal. Thus, the present invention is suitably usable in the industrial field of manufacturing of a vehicle such as an automobile equipped with a glass antenna.

LIST OF REFERENCE SIGNS

1:: vehicle window glass
2:: rear pillar cover
10:: glass antenna
11, 14:: antenna connection wire
20, 50:: FM-digital radio antenna element
30, 60:: first conductor wire
40, 70:: second conductor wire
45, 75:: feeding terminal
80:: AM antenna element

Claims

A glass antenna (10) provided at a vehicle window glass (1), comprising:
the vehicle window glass (1);

an FM-digital radio antenna element (20; 50) provided at the vehicle window glass (1), the FM-digital radio antenna element (20; 50) configured to function as an FM antenna element configured to receive a high-frequency signal in an FM broadcast band whose center-frequency wavelength is a first wavelength, and

a digital radio antenna element configured to receive a high-frequency signal in a digital radio broadcast band from 170 MHz to 240 MHz whose center-frequency wavelength is a second wavelength;

a first conductor wire (30; 60) at least partly disposed at the vehicle window glass (1), and formed to have a length such that the sum of a length obtained by dividing the length of the portion (31, 32, 33) of the first conductor wire (30; 60) disposed at the vehicle window glass (1) by a glass wavelength reduction rate of the vehicle window glass (1) and the length of the remaining portion (11; 14) of the first conductor wire (30; 60) which is not disposed at the vehicle window glass (1) becomes a length falling within a range of +/-20% with respect to the length equal to one-half of the second wavelength;

a second conductor wire (40; 70) provided at the vehicle window glass (1) and connected to a first end (P1) of the first conductor wire (30; 60), the second conductor wire (40; 70) being formed to have a length such that a length obtained by dividing the length of the second conductor wire (40; 70) by the glass wavelength reduction rate becomes a length falling within a range of +/-20% with respect to the length equal to one-quarter of the second wavelength, and disposed adjacent to the FM-digital radio antenna element (20; 50) such that it is capacitively coupled with the FM-digital radio antenna element (20; 50); and

a feeding terminal (45; 75) connected to the second end of the first conductor wire (30; 60), said glass antenna (10) being characterized in that the first conductor wire (30; 60) extends outward in a vehicle window glass width direction from the first end (P1) of the first conductor wire (30; 60) beyond the second conductor wire (40; 70) and the FM-digital radio antenna element (20; 50) such as to connect to the feeding terminal (45; 75), and the feeding terminal (45; 75) is disposed on an outer portion of the vehicle window glass (1) in the vehicle window glass width configured to be covered by a rear pillar cover (2) of the vehicle.
The glass antenna (10) as recited in claim 1, wherein the FM-digital radio antenna element (20; 50) is provided at each of two laterally opposite portions of the vehicle window glass (1) in the vehicle window glass width direction, and wherein the vehicle window glass (1) is a rear window glass.
The glass antenna (10) as recited in any one of claims 1 or 2, further comprises an AM antenna element (80) configured to receive a high-frequency signal in an AM radio broadcast band and disposed at a central portion of the vehicle window glass (1) in the vehicle window glass width direction, the AM antenna element (80) being connected to the second conductor wire (70).
The glass antenna (10) as recited in any one of claims 1 to wherein the second conductor wire (40; 70) is disposed such as to avoid capacitive coupling with a panel member (4) of a vehicle body to which the vehicle window glass is configured to be attached.