Window glass for vehicle and antenna

Window glass for vehicle may include an antenna conductor having electrodes provided on a surface of a dielectric on a side opposite from a conductive film. The conductive film may include a slot with a first end part that opens at a peripheral edge part of the conductive film. The antenna conductor may include a loop-shaped antenna element which electrodes serve as a feeding point, and projections of the electrodes onto a glass plate are located at positions not overlapping the conductive film, and a projection of the loop-shaped antenna element onto the glass plate forms a crossover part that crosses the slot.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to window glass for vehicle, having an antenna that utilizes a conductive film provided on a glass plate, and to the antenna utilizing the conductive film.

2. Description of the Related Art

FIG. 1is a cross sectional view illustrating window glass for vehicle, having a conductive film3and an intermediate film4interposed between glass plates1and2. InFIG. 1, an arrow D1indicates a vehicle exterior side, and an arrow D2indicates a vehicle interior side. Conventionally, in a case in which an antenna conductor5for receiving radio waves is formed on the vehicle interior side D2of the glass plate2of the laminated glass, the radio waves arriving from the vehicle exterior side D1may be blocked by the conductive film3, and it may be difficult to sufficiently obtain a reception characteristic required of the antenna conductor5.

In order to eliminate such inconvenience, known window glass may have an antenna function by utilizing a conductive film (for example, refer to Japanese Laid-Open Patent Publications No. 6-45817, No. 9-175166, and No. 2000-59123, and U.S. Pat. No. 5,012,255).

The Japanese Laid-Open Patent Publications No. 6-45817, No. 9-175166, and the U.S. Pat. No. 5,012,255 propose a slot antenna that utilizes a slot between the conductive film and a flange of a vehicle body to which the glass plate is fixed. In the case of the slot antenna that utilizes the slot between the conductive film and the flange of the vehicle body, the size of the slot is determined for each vehicle model, and it is difficult to cause resonance at a predetermined frequency, specifically, in order to receive radio waves in a high frequency band. Further, in order to receive radio waves in a high frequency band, a positional relationship of the flange and the conductive film needs to be accurately controlled. However, because there are differences among individual glass plates and the glass plate is fixed to the flange of the vehicle body by an adhesive, various errors may be generated in the adhesive thickness, the fixing position of the glass plate with respect to the flange, and the like. Accordingly, there is a problem in that it is difficult to form slots of identical sizes in mass production.

In addition, when a slot is provided in the conductive film in addition to the slot between the conductive film and the flange of the vehicle body as in the case of the U.S. Pat. No. 5,012,255, the effects of the conductive film may deteriorate when the additional slot is large, and there is a problem in that, when the glass plate is bent and formed by heating, a large heat distribution is generated on the glass plate depending on the existence of the conductive film, to thereby deteriorate the forming accuracy.

SUMMARY OF THE INVENTION

Accordingly, embodiments of the present invention may provide window glass for vehicle, such as automotive glass, utilizing a conductive film, and an antenna, that enable operation at a predetermined frequency regardless of the size of a slot between the conductive film and a flange of a vehicle body, and does not require accuracy in setting a glass plate to the flange of the vehicle body.

According to one aspect of the present invention, window glass for vehicle may include a glass plate, a dielectric, a conductive film arranged between the glass plate and the dielectric, and an antenna conductor having electrodes provided on a surface of the dielectric on a side opposite from the conductive film, wherein the conductive film is formed with a slot having a first end part that opens at a peripheral edge part of the conductive film, the antenna conductor includes a loop-shaped antenna element which the electrodes serve as a feeding point, wherein projections of the electrodes on a side of the glass plate are located at positions not overlapping the conductive film, and a projection of the loop-shaped antenna element on the side of the glass plate forms a crossover part that crosses the slot.

According to another aspect of the present invention, an antenna may include a glass plate, a dielectric, a conductive film arranged between the glass plate and the dielectric, and an antenna conductor having electrodes provided on a surface of the dielectric on a side opposite from the conductive film, wherein the conductive film is formed with a slot having a first end part that opens at a peripheral edge part of the conductive film, the antenna conductor includes a loop-shaped antenna element which the electrodes serve as a feeding point, projections of the electrodes on a side of the glass plate are located at positions not overlapping the conductive film, and a projection of the loop-shaped antenna element on the side of the glass plate forms a crossover part that crosses the slot.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A description will hereinafter be given of embodiments of the present invention with reference to the drawings. In the drawings used to describe the embodiments, directions refer to the directions in the figures unless otherwise indicated, and reference directions in the figures correspond to the directions indicated by symbols or reference numerals. In addition, directions that are parallel, perpendicular, and the like may tolerate an error to a certain extent that does not impair the effects of the embodiments. Further, the embodiments may be applied to a windshield mounted at the front of a vehicle, a rear window mounted at the rear of the vehicle, a side window mounted at the side of the vehicle and a window glass other than the vehicle window glass (for example, a building window glass, a ship window glass, and the like).

FIG. 2is a disassembled perspective view of vehicle window glass100in a first embodiment of the present invention. The vehicle window glass100is a laminated glass formed by laminating a glass plate11that is an example of a first glass plate arranged on the vehicle exterior side D1, and a glass plate12that is an example of a second glass plate arranged on the vehicle interior side D2. The vehicle window glass100may be flat or may have a curved shape.FIG. 2illustrates constituent elements of the vehicle window glass100in a state separated along a direction of a normal with respect to a surface of the glass plate11(or the glass plate12).

The vehicle window glass100includes the glass plate11, the glass plate12, a conductive film13, and an antenna conductor17. The glass plate12is used as a dielectric that sandwiches the conductive film13with the first glass plate11. The glass plate11and the glass plate12have the same size, and outer peripheral edges11athrough11dof the glass plate11and outer peripheral edges12athrough12dof the glass plate12have matching shapes when viewed in a direction (hereinafter referred to as a “laminating direction”) in which the glass plate12, the conductive film13, and the glass plate11are laminated. An peripheral edge part13aof the conductive film13, that is interposed between the glass plate11and the glass plate12, is offset by a predetermined distance in an in-plane direction from the outer peripheral edge11aof the glass plate11, and a slot23, having a first end part23athat opens at the peripheral edge part13aof the conductive film13, is formed. In addition, an antenna conductor17includes a loop-shaped antenna element15, which a pair of electrodes16formed by electrodes16A and16B serve as a feeding point, on the glass plate12opposite to the conductive film13.

The electrodes16are provided on a surface of the glass plate12opposite to the conductive film13, at positions not overlapping the conductive film13when the electrodes16are projected onto the glass plate11, that is, at positions closer to the outer peripheral edge11aof the glass plate11than the peripheral edge part13aof the conductive film13. In other words, as illustrated inFIG. 2, the electrodes16are provided at positions such that, when the electrodes16are projected from the laminating direction, projections21and22of the electrodes16are formed at positions where the conductive film13is not formed.

The loop-shaped antenna element15is provided on the surface of the glass plate12on the opposite side from the conductive film13, so as to intersect with the slot23in the laminating direction. In other words, as illustrated inFIG. 2, the loop-shaped antenna element15is provided at a position such that, when the loop-shaped antenna element15is projected from the laminating direction, a projection25of the loop-shaped antenna element15crosses the slot23and form a crossover part26. When viewed from the laminating direction, the loop-shaped antenna element15and the slot23may cross at an angle of 90° or at an angle other than 90°. The loop shape of the loop-shaped antenna element15is not limited to a rectangular shape, and may have other polygonal shapes including a square shape and the like, a circular shape, and an oval shape.

According to such a configuration, when the electrodes16is fed, the loop-shaped antenna element15and the slot23that mutually cross in the laminating direction are electromagnetically coupled at the crossover part26, to thereby excite a current flowing along the slot23. As a result, compared to a case in which the slot23is not provided, an antenna gain may be improved. In addition, according to such a configuration, an operation at a predetermined frequency may be enabled regardless of the size of the slot between the conductive film and a flange of a vehicle body, and an antenna utilizing the conductive film may be realized without requiring accuracy in setting the glass plate to the flange of the vehicle body.

Next, a more detailed description will be given of the embodiment of the present invention. The vehicle window glass100illustrated inFIG. 2has a laminated structure in which the conductive film13is laminated between the glass plate11and the glass plate12.

An intermediate film14A is arranged between the glass plate11and the conductive film13, and an intermediate film14B is arranged between the conductive film13and the glass plate12. The glass plate11and the conductive film13are bonded by the intermediate film14A, and the conductive film13and the glass plate12are bonded by the intermediate film14B. The intermediate films14A and14B are formed from thermoplastic polyvinyl butyral, for example. A relative permittivity ∈rof the intermediate films14A and14B is 2.8 or higher and 3.0 or lower, which is the relative permittivity of a general intermediate film of laminated glass, for example.

The glass plates11and12are formed from a transparent plate-shaped dielectric. In addition, one of the glass plates11and12may be semitransparent, and both of the glass plates11and12may be semitransparent.

The conductive film13is a heat reflecting film capable of reflecting heat from the outside. The conductive film13may be transparent or semitransparent. For example, the conductive film13may be a conductive film formed on a surface of a film-shaped polyethylene terephthalate, or a conductive film formed on a surface of a glass plate, as illustrated inFIGS. 4A,4C, and4D. In addition, the conductive film13may be a conductive film adhered on the surface of the glass plate, as illustrated inFIG. 4E. The slot23has the open end (first end part)23aat the peripheral edge part13aof the conductive film13.

The slot23is formed from the peripheral edge part13aof the conductive film13towards the in-plane direction. The peripheral edge part13aforms an outer peripheral edge of the conductive film13. For example, the slot23may be formed by linearly cutting out the conductive film13from the open end23ato a tip end (second end part)23b.

In addition, the pair of electrodes16formed by the electrode16A and the electrode16B is arranged on the opposite side with respect to the position of the conductive film13via the glass plate12. The electrodes16are exposed at the surface (that is, the surface on the opposite side with respect to the surface opposing the conductive film13) on the vehicle interior side D2of the glass plate12, so that when the electrodes16are projected from the laminating direction, the projections21and22of the electrodes16are located at positions closer to the outer peripheral edge11aof the glass plate11than the peripheral edge part13aof the conductive film13. The electrodes16A and16B are arranged side by side in a direction perpendicular to a longitudinal direction of the slot23and parallel to the surface of the glass plate12. The positional relationship of the electrode16A and the electrode16B is not limited to the above. For example, the electrodes16A and16B may be arranged in an up and down direction (that is, the direction parallel to the longitudinal direction of the slot23inFIG. 2). When the electrodes16are viewed from the laminating direction, an intermediate part between the electrodes16A and16B may be located at a position on an extension of the longitudinal direction of the slot23, or the intermediate part may be offset with respect to the extension.

Moreover, the loop-shaped antenna element15and the electrodes16are arranged on the same surface of the glass plate12. The loop-shaped antenna element15is connected to the electrodes16. In other words, the antenna conductor17forms a so-called loop antenna of dipole type together with the loop-shaped antenna element15and the electrodes16provided on the glass plate12.

For example, in a case in which the electrode16A is used as a signal line electrode and the electrode16B is used as a ground line electrode, the electrode16A is electrically connected to a signal line that is connected to a signal processing unit (for example, an amplifier and the like) that is mounted in the vehicle, and the electrode16B is electrically connected to the ground line that is connected to a grounding part of the vehicle. For example, the grounding part may be the ground of the vehicle body, the ground of the signal processing unit to which the signal line connected to the electrode16A connects, and the like. The electrode16A may be used as the ground line electrode, and the electrode16B may be used as the signal line electrode.

Reception signals of radio waves, corresponding to the current excited along the slot23and the current excited in the loop-shaped antenna element15, are transmitted to the signal processing unit mounted in the vehicle via conductive members that are electrically connected to the pair of electrodes16. Preferably, the conductive members are feeders, such as AV cables (low-voltage electric cables for automobiles) and coaxial cables.

In a case in which the coaxial cable is used as the feeders to feed to the antenna via the electrodes16A and16B, an inner conductor of the coaxial cable is electrically connected to the electrode16A, and an outer conductor of the coaxial cable is electrically connected to the electrode16B. In addition, a configuration may be employed in which connectors for electrically connecting the electrodes16A and16B to the conductive members, such as cables, that are connected to the signal processing unit, are mounted on the electrodes16A and16B. By use of such connectors, the mounting of the inner conductor of the coaxial cable to the electrode16A is facilitated, and the mounting of the outer conductor of the coaxial cable to the electrode16B is facilitated. Further, a configuration may be employed in which conductive members in the form of conductive projections are provided on the electrodes16A and16B, and the conductive projections fit into and make contact with feeding parts provided in a flange of the vehicle body to which the window glass100is mounted.

The shape of the electrode16A and the electrode16B and the separation between the electrodes16A and16B may be determined by taking into consideration the shapes of the conductive members or the connectors and the separation of the mounting surfaces. For example, a quadrate and a polygonal shape, such as a square shape, an approximately square shape, a rectangular shape, an approximately rectangular shape and the like, are preferable electrode shapes in view of mounting. Round shapes, such as a circular shape, an approximately circular shape, an oval shape, an approximately oval shape and the like are also preferable electrode shapes.

In addition, the antenna conductor17, including the electrodes16A and16B and the loop-shaped antenna element15, may be formed by printing and baking a paste that includes a conductive metal, for example a silver past, onto the surface of the glass plate12on the vehicle interior side D2. The method of forming the antenna conductor17is not limited to this method, and for example, a strips or films made of a conductive material such as copper and the like may be formed on the surface of the glass plate12on the vehicle interior side D2, and the conductive material may be adhered on the glass plate12by an adhesive or the like.

In addition, the antenna conductor17may be provided on a surface of a synthetic resin film, and the conductive film13formed with the slot23may be provided on the other surface of the synthetic resin film, in order to form a glass antenna. Moreover, a substrate such as a flexible substrate and the like may be used in place of the synthetic resin film. Such a glass antenna may be used by mounting the glass antenna on the surface of the glass plate12on the vehicle interior side D2or on the vehicle exterior side D1.

Further, the position of the loop-shaped antenna element15on the glass plate is not limited to a particular position as long as the position is suited for receiving radio waves in a predetermined frequency band. For example, the antenna in the embodiment may be arranged in a vicinity of a vehicle body opening edge that is a mounting part to which the vehicle window glass is mounted. As illustrated inFIG. 3, it may be preferable from the point of view of improving the antenna gain when the antenna is arranged in a vicinity of a vehicle body opening edge41on the vehicle roof side. In addition, the antenna may be arranged at a position moved to the right or left from the position illustrated inFIG. 3, to a vicinity of a vehicle body opening edge42or44on the vehicle body pillar side. Moreover, the antenna may be arranged at a position in a vicinity of a vehicle body opening edge43on the vehicle body chassis side. In the example illustrated inFIG. 3, the longitudinal direction of the slot23is perpendicular to the vehicle body opening edge41, and matches a direction that is perpendicular to the peripheral edge part13aof the conductive film13.

FIG. 3is a front view (viewed within vehicle) of vehicle window glass200in a second embodiment of the present invention.FIG. 3illustrates a state in which the vehicle window glass200is mounted in the vehicle body opening. The vehicle window glass200is a laminated glass having a configuration similar to that illustrated inFIG. 2. The vehicle window glass200is mounted on a flange, which is a window frame formed on the vehicle body, using adhesive or the like. The vehicle opening edges41through44also form flange peripheral edge parts. The glass plate12having the same size as the glass plate11is used as the dielectric that sandwiches the conductive film13with the glass plate11. From the point of view of improving the antenna gain, a mounting angle of the window glass with respect to the vehicle is preferably 15° to 90°, and more preferably 30° to 90°, with respect to a horizontal plane (ground plane).

The peripheral edge parts13athrough13dforming the outer peripheral edges of the conductive film13are offset by the predetermined distance towards the inside from the outer peripheral edges11athrough11dof the glass plate11. By providing such an offset, the conductive film13may be prevented from corrosion caused by immersion and the like from matching surfaces of the glass plate11and the glass plate12. In addition, in the example illustrated inFIG. 3, a recess is formed at the top peripheral edge part13aof the conductive film13, in a region where the conductive film13is receded towards the in-plane side and is not formed. The slot23is formed from a boundary line of this recess, and the electrodes16are provided in regions of the glass plate12corresponding to this recess. According to this configuration of the embodiment, the region where the antenna is to be formed may be secured even in a case in which the conductive film13is formed to a vicinity of the outer peripheral edge of the glass plate11. The antenna may also be formed without providing the recess in the conductive film13.

A concealing film may be formed on the glass plate12, and a part or all of the antenna conductor17may be provided on this concealing film. Alternatively, a concealing film may be formed on the glass plate11in a region corresponding to a part or all of the antenna conductor17. The part of the antenna conductor17is preferably a part of the loop-shaped antenna element15and the electrodes16. For example, a ceramic film such as a black ceramic film and the like may be used as the concealing film. In this case, when viewed from the vehicle exterior side D1of the vehicle window glass200, the part of the antenna conductor provided on the concealing film is either not visible or difficult to identify due to the concealing film, to thereby improve the design of the window glass. In the example illustrated inFIG. 3, it may be preferable to provide the concealing film to cover the entire region corresponding to the recess, from the point of view of shielding heat wave by the concealing film, in place of the conductive film13.

FIGS. 4A through 4Eare cross sectional views of the vehicle window glass200along a line A-A inFIG. 3.FIGS. 4A through 4Eillustrate variations of the laminated configuration employed by the vehicle window glass and the antenna in the embodiments. As illustrated inFIGS. 4A through 4E, the conductive film13is arranged between the glass plate11and the dielectric (that is, the glass plate12or the dielectric substrate32). The conductive film13makes contact with a bonding layer between the glass plate and the dielectric.

In the cases illustrated inFIGS. 4A through 4C, the conductive film13and the intermediate film14(or the intermediate films14A and14B) are arranged between the glass plate11and the glass plate12.FIG. 4Aillustrates a state in which the conductive film13is coated on the glass plate12, by a deposition process that deposits the conductive film13on the surface of the glass plate12opposing the glass plate11.FIG. 4Billustrates a state in which the film-shaped conductive film13is interposed between the intermediate film14A, which makes contact with the surface of the glass plate11opposing the glass plate12, and the intermediate film14B, which makes contact with the surface of the glass plate12opposing the glass plate11. The film-shaped conductive film13may be coated on a film by a deposition process that deposits the conductive film13.FIG. 4Cillustrates a state in which the conductive film13is coated on the glass plate11, by a deposition process that deposits the conductive film13on the surface of the glass plate11opposing the glass plate12.

In addition, as illustrated inFIGS. 4D and 4E, the vehicle window glass in the embodiments does not need to be laminated glass. In this case, the dielectric does not need to have the same size as the glass plate11, and the dielectric may be formed by a dielectric substrate or the like having a size that enables forming of the antenna conductor17. In the cases illustrated inFIGS. 4D and 4E, the conductive film13is arranged between the glass plate11and the dielectric substrate32.FIG. 4Dillustrates a state in which the conductive film13is coated on the glass plate11, by a deposition process that deposits the conductive film13on the surface of the glass plate11opposing the dielectric substrate32. The conductive film13and the dielectric substrate32are bonded by an adhesive38, and the glass plate11and the dielectric substrate32are bonded by the adhesive38.FIG. 4Eillustrates a state in which the conductive film13is bonded on the surface of the glass plate11opposing the dielectric substrate32by an adhesive38A. The conductive film13and the dielectric substrate32are bonded by the adhesive38A, and the glass plate11and the dielectric substrate32are bonded by an adhesive38B. The dielectric substrate32may be formed by a resin substrate that is made of a resin, and may be provided with the electrodes16and the loop-shaped antenna element15. The resin substrate may be a printed substrate having the electrodes16and the loop-shaped antenna element15printed thereon.

As may be seen fromFIGS. 4A through 4E, the electrodes16are provided on the glass plate12or the dielectric substrate32at positions closer to the outer peripheral edge of the glass plate than the peripheral edge part of the conductive film13(so as not to overlap the conductive film13when viewed from the laminating direction).

FIG. 5Ais a front view of an antenna19illustrating an antenna part ofFIGS. 2 and 3on an enlarged scale. The loop-shaped antenna element15has a shape and dimensions suited for receiving radio waves in a predetermined frequency band. The shape and dimensions of the loop-shaped antenna element15are not limited to particular values as long as the shape and dimensions are set to satisfy the required value of the antenna gain that is required to receive the radio waves in the predetermined frequency band.

When a wavelength in air at a center frequency of the predetermined frequency band of the loop-shaped antenna element15is denoted by λ0, a shortening coefficient of wavelength for glass is denoted by k (where k=0.64), and λg=λ0·k, preferable results may be obtained from the point of view of improving the antenna gain in the predetermined frequency band when a loop length L1of the loop-shaped antenna element15(=H1×2+W1×2) is λgor longer and (7/5)·λgor shorter. The loop length as used in the embodiments includes the separation between the electrodes16A and16B.

For example, in order to improve the antenna gain the predetermined frequency band having the center frequency of 310 MHz, and the velocity of the radio waves is 3.0×108m/s, the loop length L1of the loop-shaped antenna element15may be adjusted to 640 mm or longer and 900 mm or shorter.

In addition, when the slot length H2from the crossover part26where the loop-shaped antenna element15and the slot23cross to the tip end23bof the slot23is ( 3/16)·λgor longer and ( 5/16)·λgor shorter, preferable results may be obtained from the point of view of improving the antenna gain in the predetermined frequency band.

For example, in order to improve the antenna gain the predetermined frequency band having the center frequency of 310 MHz, and the velocity of the radio waves is 3.0×108m/s, the slot length H2may be adjusted to 120 mm or longer and 200 mm or shorter.

FIG. 5Bis a front view of an antenna20in a third embodiment of the present invention, including the dielectric12, the conductive film13, and the antenna conductor17. As illustrated inFIG. 5B, other independent slots may be formed in the conductive film13at a position separated from the slot23. Independent slots24A and24B are formed in the conductive film13and have one end thereof that opens at the peripheral edge part13a, in a manner similar to the slot23. The independent slots24A and24B are arranged on both sides of the slot23at positions separated from the slot23, so that the projection of the loop-shaped antenna element15on the glass plate11does not intersect the slot23. In addition, although not specifically illustrated, an independent slot that is not continuous with the slot23may be formed adjacent to the slot23, so that this independent slot closes within the conductive film13without making contact with the outer peripheral edge of the conductive film13. By providing such an independent slot, the band of the antenna may be broadened when compared to a case in which such an independent slot is not provided.

Practical Example 1

Numerical calculation was performed on a computer with respect to the antenna19of the embodiment illustrated inFIG. 5A, by assuming the window glass to be laminated glass formed by two glass plate11and12having a square shape with vertical and horizontal sides of 500 mm and a thickness of 2.0 mm that are bonded via two intermediate films14A and14B as illustrated inFIG. 4B. The pair of electrodes16A and16B are arranged on the surface, assumed to be on the vehicle interior side D2, of the glass plate12, assumed to be on the vehicle interior side D2, and the conductive film13formed with the slot23is arranged between the two intermediate films14A and14B. The conductive film13has a size such that a vertical side is 250 mm and a horizontal side is 500 mm. The peripheral edge part13ais set to pass a center along the up and down direction of the glass plate, and the slot23is set to pass a center along the right and left direction of the glass plate. The antenna conductor17is arranged so that the center along the right and left direction of the loop-shaped antenna element, the intermediate part between the electrodes16A and16B, and the extension along the longitudinal direction of the slot23match. It is assumed that the vehicle body and a defogger do not exist.

In addition, dimensions of each of the other parts are set as follows, where the units of the values are in mm.H1: 48.75H2: 163.125H3: 187.5

With respect to the antenna19set with these numerical values, an electromagnetic field simulation based on the FDTD method (Finite-Difference Time-Domain method) was made to perform numerical calculation of a return loss (reflection coefficient) (S11) for every 5 Hz in frequencies of 200 MHz to 400 MHz. The closer the S11value is to zero the larger the return loss and the smaller the antenna gain, and the larger the negative value of the S11the smaller the return loss and the larger the antenna gain.

FIG. 6is a graph illustrating an example of simulation results of the S11. InFIG. 6, “a” indicates the simulation results with respect to the embodiment ofFIG. 5Awhen no conductive film13is provided, “b” indicates the simulation results with respect to the embodiment ofFIG. 5Awhen no slot23is provided (conductive film13is provided), and “c” indicates the simulation results with respect to the embodiment ofFIG. 5A.

As may be seen from a comparison of the simulation results for the case “a” and the case “b”, the provision of the conductive film13not formed with the slot23will not enable an antenna function. However, by providing the slot23that crosses the loop-shaped antenna element15with respect to the case “b”, the loop-shaped antenna element15and the slot23become electromagnetically coupled and a current may flow along the slot23, to thereby enable satisfactory matching in a vicinity of 300 MHz as indicated in the case “c” and enable the antenna function.

Hence, according to the configuration described above, an antenna utilizing a conductive film may be configured without using a slot between a flange of a vehicle body and the conductive film. Because the flange of the vehicle body is not utilized, accuracy in setting a glass plate to the flange of the vehicle body may not be required. In addition, since it is unnecessary to form a hole in the glass plate and it is unnecessary to provide a feeding conductor that uses a detour route on an outer side of the outer peripheral edge of the glass plate, the antenna utilizing the conductive film may be realized with a simple configuration.

According to the embodiments, it is possible to realize an antenna utilizing a conductive film, that enables operation at a predetermined frequency regardless of the size of the slot between the conductive film and the flange of the vehicle body, and does not require accuracy in setting a glass plate to the flange of the vehicle body.

The embodiments may preferably be utilized as an antenna for an automobile to receive digital terrestrial television broadcasting, analog television broadcasting in the UHF band, digital television broadcasting in the United States, digital television broadcasting in the European Union states, or digital television broadcasting in the People's Republic of China, for example. Other usages of the antenna may include the FM broadcasting band (76 MHz to 90 MHz) in Japan, the FM broadcasting band (88 MHz to 108 MHz) in the U. S., television VHF bands (90 MHz to 108 MHz, 170 MHz to 222 MHz), or keyless entry system (300 MHz to 450 MHz) for vehicles, for example.

In addition, other usages may include communication in the 800 MHz band (810 MHz to 960 MHz) for mobile phones, the 1.5 GHz band (1.429 GHz to 1.501 GHz) for mobile phones, GPS (Global Positioning System) (the satellite GPS signal: 1575.42 MHz), and the VICS (registered trademark) (Vehicle Information and Communication System: 2.5 GHz).

Furthermore, other usages may include communication in the ETC (Electronic Toll Collection system: non-stop automatic toll collection system) communication (transmission frequency of road side wireless device: 5.795 GHz or 5.805 GHz, reception frequency of road side wireless device: 5.835 GHz or 5.845 GHz), the DSRC (Dedicated Short Range Communication, 915 MHz band, 5.8 GHz band, 60 GHz band), the microwave communication (1 GHz to 3 THz), the millimeter-wave communication (30 GHz to 300 GHz), and the SDARS (Satellite Digital Audio Radio Service, 2.34 GHz, 2.6 GHz).

The vehicle window glass and the antenna are described above with reference to the embodiments, however, it may be apparent to those skilled in the art that the present invention is not limited to the above embodiments, and various variations and modifications may be made without departing from the spirit and scope of the present invention.