WO2010119856A1 - Vehicle glass antenna, vehicle window glass, and vehicle glass antenna feeding structure - Google Patents

Abstract

A vehicle glass antenna in which an earth portion is a region for electrically connecting a non-feeding conductor to a vehicle body and a feeding portion and the earth portion are disposed side by side along a reference direction. An antenna conductor comprises: a first element having a starting point at the feeding portion and extending in a first direction that is a direction parallel with the reference direction and pointing toward the opposite side of the earth portion; a second element connected to a first terminal portion that is an end of the first element on the opposite side from the feeding portion and extending in a second direction that is a direction orthogonal to the first element and pointing toward the inner side with respect to the outer circumference of a window glass; and a third element having a starting point at the second element and extending in a third direction that is the opposite direction to the first direction. The non-feeding conductor includes non-feeding element that is an element, at least a part of which extends in the second direction with a starting point at the earth portion.

Description

VEHICLE GLASS ANTENNA, VEHICLE WINDOW GLASS, AND VEHICLE GLASS ANTENNA FEEDING STRUCTURE

The present invention relates to a vehicle glass antenna and a vehicle window glass in which an antenna conductor and a parasitic conductor are provided on a window glass, and a power supply structure of the vehicle glass antenna.

Conventionally, there has been known a glass antenna that is provided on the surface of a window glass of an automobile and transmits / receives radio waves in a high frequency band, as described in Japanese Patent Application Laid-Open No. 2007-110390. The glass antenna described in Japanese Patent Application Laid-Open No. 2007-110390 includes a parasitic line disposed in the vicinity of the antenna line.

However, the conventional glass antenna exhibits excellent reception sensitivity in the vehicle front-rear direction by being installed on at least one of the windshield and the rear glass, but sufficient antenna gain is obtained on the side of the vehicle. Not. On the other hand, miniaturization of antennas is required for reasons such as designability and occupant visibility.

Accordingly, the present invention provides a glass antenna for a vehicle and a window glass for a vehicle that can improve the reception sensitivity on the side of the vehicle while miniaturizing a glass antenna suitable for receiving radio waves in a high frequency band such as terrestrial digital broadcasting. An object of the present invention is to provide a feeding structure for a glass antenna for a vehicle.

In order to achieve the above object, the present invention provides a vehicle in which an antenna conductor, a feeding portion connected to the antenna conductor, a parasitic conductor, and a ground portion connected to the parasitic conductor are provided on a window glass. In the glass antenna for use, when the window glass is mounted on a vehicle, the power feeding portion is a portion for electrically connecting the antenna conductor to a signal processing circuit mounted on the vehicle, and the ground portion is , A portion for electrically connecting the parasitic conductor to the vehicle body, the feeding portion and the grounding portion are arranged along a reference direction, and the antenna conductor starts from the feeding portion, A first element extending in a first direction that is parallel to the reference direction and directed toward the opposite side of the ground portion, and a first termination that is the end of the first element on the opposite side of the power feeding portion Connected to the A second element extending in a second direction that is orthogonal to the first element and directed inward with respect to the outer periphery of the window glass; and starting from the second element, in the first direction And a third element extending in a third direction that is the opposite direction, and the parasitic conductor is an element that extends at least partially in the second direction from the ground portion. Provided is a glass antenna for a vehicle comprising a parasitic element.

Further, it is preferable that the antenna conductor includes a fourth element extending in the first direction starting from the second element.

In addition, it is preferable that the parasitic conductor includes an accessory parasitic element that is parallel to the reference direction and connected to the parasitic element.

In order to achieve the above object, the present invention provides a vehicle window glass provided with the vehicle glass antenna according to the present invention.

In order to achieve the above object, the present invention provides a vehicle window glass according to the present invention, a first conductive member that electrically connects the power feeding portion to the signal processing circuit, and the ground portion as a vehicle body. And a second conductive member electrically connected to the vehicle glass antenna feeding structure.

According to the present invention, it is possible to improve the reception sensitivity on the side of a vehicle while reducing the size of a glass antenna suitable for receiving radio waves in a high frequency band such as terrestrial digital broadcasting.

It is a top view of the glass antenna 100 for vehicles. It is a top view of the glass antenna 200 for vehicles. It is a top view of the glass antenna 300 for vehicles. It is a top view of the glass antenna 400 for vehicles. It is a top view of the glass antenna 500 for vehicles. It is a top view of the glass antenna 600 for vehicles. It is a top view of the glass antenna 700 for vehicles. It is a top view of the glass antenna 800 for vehicles. It is a top view of the glass antenna 900 for vehicles. It is sectional drawing which showed the electric power feeding structure of an electric power feeding part. It is sectional drawing which showed the electric power feeding structure of an earth part. It is a schematic diagram of the electric power feeding structure of the glass antenna 100 for vehicles which is embodiment of this invention. It is a schematic diagram of the electric power feeding structure of the conventional glass antenna X for vehicles. It is a frequency characteristic figure of antenna gain of glass antenna 100 and glass antenna X. It is a direction characteristic figure of the directivity of glass antenna 100 and glass antenna X. This is actual measurement data of antenna gain when the conductor length x4 is changed. This is measured data of antenna gain when the overlap distance xs1 in the horizontal direction between the terminal end 3g and the terminal end 6g is changed. FIG. 6 is a frequency characteristic diagram of antenna gain of glass antennas 100 to 600. FIG. 5 is a frequency characteristic diagram of antenna gains of glass antennas 100A, 100B, 700 to 900. It is sectional drawing of the aspect different from FIG. 10B which showed the electric power feeding structure of an earth | ground part. It is a perspective view of the elastic connection member 31 which is a 2nd electroconductive member. It is sectional drawing of the aspect different from FIG. 10B which showed the electric power feeding structure of an earth | ground part.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. Note that in the drawings for describing the embodiments, the directions on the drawings are used unless otherwise specified. In addition, these drawings are views of the interior of the vehicle with the window glass attached to the vehicle, but may be referred to as a view of the exterior of the vehicle. For example, when the window glass is a windshield attached to the front portion of the vehicle, the left-right direction on the drawing corresponds to the vehicle width direction. Further, in the present invention, the power feeding part and the ground part are arranged side by side along the reference direction, but the reference direction can be freely set by the installation area of the glass antenna, and particularly if it is a window glass for a vehicle, It is preferable to set the direction parallel to the edge of the window glass, the horizontal direction or the vertical direction.
In the form described below, the horizontal plane when the vehicle window glass is mounted on the vehicle is the reference direction. In addition, this invention is not limited to a windshield, The rear glass attached to the rear part of a vehicle, and the side glass attached to the side part of a vehicle may be sufficient.

FIG. 1 is a plan view of a glass antenna 100 for a vehicle according to the present invention. The glass antenna 100 for a vehicle includes an antenna conductor, a parasitic conductor disposed in the vicinity of the antenna conductor, and a feeding portion 16A and a ground portion 16B that are separated from each other in a predetermined reference direction (for example, a horizontal or substantially horizontal direction). This is an antenna provided in a plane on the vehicle window glass 12.

The glass antenna for vehicle 100 includes, as an antenna conductor pattern, an antenna element 1 that is a first element, an antenna element 2 that is a second element, an antenna element 3 that is a third element, and a fourth element. An antenna element 4 is provided. The antenna element 1 extends in a first direction (right direction in the drawing), which is a direction parallel to the reference direction and toward the opposite side of the ground portion 16B, starting from the feeding portion 16A.
The antenna element 2 is connected to the first terminal end 1g (that is, the terminal opposite to the power feeding unit 16A) that is the terminal of the extension of the antenna element 1 in the first direction, and is orthogonal to the antenna element 1 and the window glass. 12 extends in the second direction (downward in the drawing), which is the direction toward the inside with respect to the outer periphery of 12. The antenna element 2 may extend linearly in the second direction starting from the terminal end 1g, or may be curved and extended in the second direction. The antenna element 3 starts in the third direction (left direction in the drawing) that is the direction opposite to the first direction, starting from the second terminal end 2g that is the terminal end of the extension of the antenna element 2. Stretch. And the 3rd termination | terminus part 3g which is the termination | terminus of the extending | stretching to the 3rd direction of the antenna element 3 is located in the 1st direction side with respect to the below-mentioned parasitic element 5 (namely, in the parasitic element 5). On the right hand side). The antenna element 4 extends in the first direction starting from a point on the antenna element 2. The starting point of the antenna element 4 in FIG. 1 extends in the first direction starting from the terminal end 2g.

The antenna element 4 may be omitted. However, as described later, the glass antenna provided with the antenna element 4 improves the average sensitivity of the glass antenna as compared with the case where the antenna element 4 is not provided.

The glass antenna 100 for a vehicle includes a parasitic element 5 that is a parasitic element and a parasitic element 6 that is an attached parasitic element as a parasitic conductor pattern. The parasitic element 5 is an element that extends at least partially in the second direction from the ground portion 16B. The parasitic element 6 extends in parallel with the reference direction and is connected to the parasitic element 5, and is a fifth termination portion 5 g that is a termination of the parasitic element 5 in the second direction. Pass through.

Although the parasitic element 6 may be omitted, the glass antenna provided with the parasitic element 6 improves the average sensitivity of the glass antenna as compared to the case where the parasitic element 6 is not provided.

Here, the “termination part” may be an end point of extension of the parasitic element or the antenna element, or may be in the vicinity of the end point which is a conductor portion before the end point.

The antenna conductor connected to the power feeding unit 16A and the power feeding unit 16A, and the parasitic conductor connected to the ground unit 16B and the ground unit 16B are made of a paste containing a conductive metal, such as silver paste, on the inside of the window glass plate. It is formed by printing on the surface and baking. However, the present invention is not limited to this forming method, and a linear body or a foil-like body made of a conductive material such as copper may be formed on the vehicle-side surface or the vehicle-outside surface of the window glass, and the window glass is adhesive. It may be attached by, for example, or may be provided inside the window glass itself.

If it is a conventional glass antenna, it is used as a dipole antenna if it has a power feeding part and a grounding part, and connects the inner conductor of the coaxial cable and the power feeding part, and the outer conductor and the grounding part of the coaxial cable. And connect the glass antenna to the amplifier via a coaxial cable. The glass antenna for a vehicle of the present invention is different in that the ground portion 16B is directly connected to the vehicle body panel, and is a monopole antenna. A radio wave reception signal received by the antenna conductor is transmitted to a signal processing circuit mounted on the vehicle via a first conductive member electrically connected to a power feeding portion 16A corresponding to a power feeding point. On the other hand, the parasitic conductor is grounded to the vehicle body via a second conductive member for electrically connecting the ground portion 16B and the vehicle body. The term “electrically connected” includes that the conductors are in direct contact with each other and are connected in a direct current, and that the conductors are separated from each other by a predetermined distance to form a capacitor and are electrically connected at a high frequency.

FIG. 10A is a cross-sectional view showing an example of a connection structure for electrically connecting the power feeding unit 16A and the signal processing circuit 20. FIG. FIG. 10B is a cross-sectional view showing an example of a connection structure for grounding the ground portion 16B and the vehicle body.

In FIGS. 10A and 10B, 12 is a vehicle window glass, 11 is a vehicle body panel (entire view is omitted) consisting of an inner panel 11a and an outer panel 11b, and its end is L for installing the window glass 12 on the vehicle body. A flange is formed in a letter shape. 13 is an adhesive (or packing) for bonding the flange of the vehicle body panel 11 and the window glass 12, 14 is an antenna unit disposed in the vehicle interior (lower side in the figure), and 18 is fixed on the vehicle interior side of the inner panel 11a. 20 is a signal processing circuit (for example, a printed wiring board on which a receiving circuit such as an amplifier is mounted), 22 is an insulating sheet, and 28A and 28B are insulating resins such as ABS. A holder 29A made of a material is held in a cylindrical portion of the holder 28A so as to be extendable and contracted, and a joining member as a first conductive member disposed oppositely below the power feeding portion 16A. 29B is a cylindrical portion of the holder 28B. A joining member as a second conductive member, which is held so as to be stretchable and is opposed to the lower side of the ground portion 16B, 30A is a lower end surface of the joining member 29A Conductive connecting member for electrically connecting the signal processing circuit 20, 30B are connected electrically conductive member which electrically connects the cover 24 of the lower end surface of joint member 29B and the amplifier case 18.

The amplifier case 18 includes a base member 23 having a substantially cross-sectional crank shape and a cover 24 held by the base member 23. The base member 23 is held by the inner panel 11a by screwing bolts 27 into nuts 26 fixed to the inner panel 11a which is a ground member on the vehicle body side. The base member 23 and the cover 24 may be made of metal, or may be made by attaching a conductor to the entire resin surface.

With such a connection structure, a radio wave reception signal received by the antenna conductor of the glass antenna is reliably supplied to the signal processing circuit 20 via the power supply portion 16A, the joining member 29A, and the connecting member 30A. be able to. Further, the ground portion 16B of the glass antenna and the parasitic conductor connected to the ground portion 16B can be securely grounded to the vehicle body via the joining member 29B, the coupling member 30B, and the amplifier case 18 (the cover 24). .

Note that the further detailed structure of FIG. 10A is the same as the content disclosed in Japanese Patent Application Laid-Open No. 2003-347817, so the description thereof is omitted.
Further, instead of the joining member 29B and the connecting member 30B, as shown in FIG. 18, an elastic connecting member 31 may be provided as a second conductive member in the ground portion 16B to be electrically connected to the vehicle body. As shown in FIG. 19, the elastic connection member 31 is provided with a metal plate 35 having a connection portion 34 to be electrically connected to the ground portion 16B by soldering or the like, and the metal plate 35 being curved in an arch shape. It consists of an elastic plate 33. The elastic connecting member 31 may adhere the metal plate 35 to the ground portion 16B with an adhesive or the like and connect it to the ground portion 16B at high frequency. When the window glass 12 is bonded to the end portion of the vehicle body panel 11 via the adhesive 13, the elastic plate 33 is elastically deformed to contact the surface of the elastic connection member 31 installed on the ground portion 16B with the vehicle body panel 11 on the surface. To do. As a result, the ground portion 16B can be grounded to the vehicle body panel 11 without any special configuration on the vehicle body side.
On the other hand, the outer surface of the outer panel 11b of the vehicle body panel 11 is usually coated with a paint or the like to form an insulating paint film 32, and a DC connection is not ensured only by contacting the elastic connecting member 31. . However, since the elastic plate 33 is elastically deformed and the area in contact with the coating film 32 is sufficiently large, the elastic connecting member 31 is connected to the outer panel 11b in a high frequency manner, so that the ground portion 16B is grounded to the vehicle body. be able to.
As a 2nd electroconductive member, the form of FIG. 10B and FIG. 18 is an example, What is necessary is just a means to electrically connect to the vehicle body panel 11. FIG. It is good also as a structure which installs a protrusion-shaped electroconductive member in the earth part 16B, and a protrusion-shaped electroconductive member contacts and fits the flange of the vehicle body to which a window glass plate is attached. Moreover, you may provide the convex part 36 as shown in FIG. 20 in the edge part of the outer panel 11b of the vehicle body panel 11 instead of a 2nd electroconductive member. When the ground portion 16B comes into contact with the convex portion 36, the ground portion 16B comes into direct contact with the vehicle body panel 11 and can be grounded. In this case as well, even if the insulating paint film 32 is formed on the outer panel 11b, the area where the ground portion 16B and the convex portion 36 are opposed to each other is sufficiently large, so that the convex portion 36 is high frequency in terms of the outer panel. Since it is connected to 11b, the ground part 16B can be grounded to the vehicle body. The same applies even if the ground portion 16B and the convex portion 36 are not in direct contact.

When a coaxial cable is used as a power supply line for supplying power to the antenna conductor via the power supply portion 16A, the inner conductor of the coaxial cable is electrically connected to the power supply portion 16A, and the outer conductor of the coaxial cable is connected to the vehicle body. Connect to ground. Further, the outer conductor of the coaxial cable may be connected to the ground part 16B and grounded to the vehicle body via the ground part 16B.

Moreover, you may employ | adopt the structure which mounts in the electric power feeding part 16A the connector for electrically connecting electroconductive members, such as conducting wire connected to the signal processing circuit, and the electric power feeding part 16A. Moreover, you may employ | adopt the structure which mounts in the earth | ground part 16B the connector for electrically connecting electrically conductive members, such as conducting wire currently earth | grounded by the vehicle body, and the earth | ground part 16B.
In addition, a connector for electrically connecting the inner conductor of the coaxial cable and the feeding portion 16A and electrically connecting the outer conductor of the coaxial cable and the ground portion 16B is mounted on the feeding portion 16A and the ground portion 16B. A configuration may be adopted. In this case, the ground portion 16B is electrically connected to the vehicle body separately from the connector, and the outer conductor of the coaxial cable is grounded to the vehicle body via the ground portion 16B. With such a connector, it is easy to attach the inner conductor of the coaxial cable to the power feeding portion 16A, and it is easier to attach the outer conductor to the ground portion 16B. Further, an amplifier may be mounted on the connector.
The conductor length of the path required for electrically connecting the ground portion 16B to the vehicle body panel 11 is preferably 50 mm or less from the viewpoint of improving the reception sensitivity. That is, it is preferable that the second conductive member has a conductor length from the ground portion 16B to the vehicle body of 50 mm or less. More preferable is 30 mm or less, and further 15 mm or less. The conductor length from the ground portion 16B to the vehicle body is the conductor length D of the joining member 29B and the connecting member 30B in the case of FIG. 10B. In the case of FIG. 18, the elastic connecting member 31 is attached to the vehicle body panel 11. It is a conductor length D in a state of being elastically deformed. The conductor length D may be 0 mm, and the conductor length D is 0 mm in the embodiment of FIG. In the case of connection at a high frequency, the conductor interval forming the capacitor is excluded.

The shape of the grounding part 16B and the power feeding part 16A and the distance between the grounding part 16B and the power feeding part 16A include the shape of the joint member 29A, 29B, the elastic connection member 31, the convex part 36 of the vehicle body panel or the mounting surface of the connector, It may be determined according to the interval between the mounting surfaces. For example, a square shape or a polygonal shape such as a square, a substantially square, a rectangle, or a substantially rectangle is preferable for mounting. It may be a circle such as a circle, a substantially circle, an ellipse, or a substantially ellipse. Further, the area of the ground part 16B and the area of the power feeding part 16A may be the same or different. In the case of FIG. 1, the ground portion 16B is provided in the vicinity of the third direction side (left side) of the power feeding portion 16A, and the right edge portion of the ground portion 16B and the left edge portion of the power feeding portion 16A face each other. Further, an imaginary straight line connecting the center of gravity of the ground portion 16B and the center of gravity of the feeding portion 16A is parallel to the extending direction of the parasitic element 6 and parallel to the extending direction of the antenna element 1 and to the extending direction of the antenna element 3. It is a preferred embodiment that they are parallel.

FIGS. 2 to 6 are plan views of a glass antenna for a vehicle in which the antenna element 4 of the glass antenna 100 for a vehicle in FIG. 1 is modified. For example, as shown in FIGS. 2 to 6, the antenna element 4 extends from a point on the antenna element 2 (including the terminal end 1g and the terminal end 2g) as a starting point. In the case of FIG. 2, the antenna element 4 extends in the right direction starting from the terminal end 1g. In the case of FIG. 3, the antenna element 4 extends downward from the element base 4 a extending rightward from the terminal end 1 g and the base terminal end 4 ag, which is the terminal of the element base 4 a extending rightward. Folded portions (4b, 4c) that are folded in the left direction and extend along the element base portion 4a in parallel. In the case of FIG. 4, after the antenna element 4 extends upward from the element base portion 4a extending rightward from the end portion 2g and the base end portion 4ag that is the terminal end of the element base portion 4a extending rightward. Folded portions (4b, 4c) that are folded in the left direction and extend along the element base portion 4a in parallel. 3 and 4, the extension end portion 4 cg of the component 4 c of the folded portion (4 b, 4 c) is located on the right side with respect to the antenna element 2. In the case of FIGS. 5 and 6, the antenna element 4 includes, as constituent elements of the element base 4a, an element base 4aa extending rightward from the terminal end 1g and an element base 4ab extending rightward from the terminal end 2g. With. In other words, the antenna element 4 may be provided with one antenna base extending rightward from one point on the antenna element 2 (see FIGS. 1 to 4), and a plurality of points on the antenna element 2 may be provided. A plurality of antenna bases extending in the right direction may be provided as starting points (see FIGS. 5 and 6). Furthermore, the antenna element 3 in the case of FIG. 6 is an additional element part (a part of the antenna element 3) that extends upward from the terminal end 3 ag, then turns rightward and extends along the antenna element 3 a in parallel. 3b, 3c). The terminal portion of the additional element portion (3b, 3c) extending in the right direction of the component 3c is located on the left side with respect to the antenna element 2.

On the other hand, in FIG. 1, the parasitic element 5 may be extended from the point on the lower side of the ground part 16B as a starting point and the terminal part 5g as the end point. The starting point of the antenna element 1 in FIG. 1 is a point on the lower side on the left side of the center point of the lower side of the ground portion 16B. It is good also as an intersection of the left side and lower side of earthing part 16B.

The parasitic element 6 may be extended in the right direction starting from the terminal end 5g and starting from the terminal end 6g.

7 and 8 are plan views of the vehicle glass antenna obtained by modifying the parasitic element 6 of the vehicle glass antenna 100 of FIG. As shown in FIGS. 7 and 8, the parasitic element 6 may extend in the horizontal direction through the terminal end 5g. In the case of FIG. 7, the parasitic element 6 extends in the left direction starting from the terminal end 5g and starting from the terminal end 6g. In the case of FIG. 8, the parasitic element 6 extends in the left and right directions starting from the terminal end 5g and starting from the terminal ends 6rg and 6lg.

By the way, in the present invention, the wavelength in the air at the center frequency of the broadcast frequency band to be received is λ ₀ , the glass wavelength shortening rate is k (where k = 0.64), and λ _g = λ ₀ · k. Then, the sum of the conductor length x5 of the parasitic element 5 and the conductor length x6 of the parasitic element 6 is (4/64) λ _g to (13/64) λ _g (in particular, (6/64) λ _g (11/64) λ _g ) is preferable in terms of improving the antenna gain in the broadcast frequency band. In particular, x5 is preferably (1/64) λ _g to (5/64) λ _g (particularly (2/64) λ _g to (4/64) λ _g ), and x6 is ( 3/64) λ _g to (8/64) λ _g (particularly, (4/64) λ _g to (7/64) λ _g ) is preferable.

Here, for example, the center frequency of the terrestrial digital television broadcasting band (470 to 770 MHz) in Japan is 620 MHz, and λ _{g at} 620 MHz is 309.7 mm. Of the terrestrial digital television broadcast bands, when 470 to 600 MHz, which is currently being broadcast, is used as the reception frequency band, 535 MHz can be set as the center frequency, and among the terrestrial digital television broadcast bands, 470 to 710 MHz. 590 MHz as the reception frequency band, 590 MHz can be set as the center frequency.

Therefore, for example, when it is desired to improve the antenna gain of the terrestrial digital television broadcasting band (473 to 713 MHz), the center frequency of the terrestrial digital television broadcasting band (473 to 713 MHz) is about 600 MHz (strictly 593 MHz). x5 + x6) may be adjusted to 20 to 65 mm (particularly 30 to 55 mm). At this time, x5 may be adjusted to 5 to 25 mm (particularly 10 to 20 mm), and x6 may be adjusted to 15 to 40 (particularly 20 to 35 mm).

In the present invention, when the wavelength in the air at the center frequency of the broadcast frequency band to be received is λ ₀ , the glass wavelength shortening rate is k (where k = 0.64), and λ _g = λ ₀ · k. The sum of the conductor length x1 of the antenna element 1, the conductor length x2 of the antenna element 2, and the conductor length x3 of the antenna element 3 is (37/64) λ _g to (57/64) λ _g (in particular, (42 / 64) λ _g to (52/64) λ _g ) is preferable in terms of improving the antenna gain in the broadcast frequency band. In particular, x1 is preferably (16/64) λ _g to (24/64) λ _g (particularly (18/64) λ _g to (22/64) λ _g ), and x2 is ( 1/64) λ _g to (5/64) λ _g (particularly, (2/64) λ _g to (4/64) λ _g ), and x3 is (20/64) λ _g It is preferable to be (28/64) λ _g (particularly (22/64) λ _g to (26/64) λ _g ).

Therefore, for example, when it is desired to improve the antenna gain of the terrestrial digital television broadcasting band (473 to 713 MHz), the center frequency of the terrestrial digital television broadcasting band (473 to 713 MHz) is about 600 MHz (strictly 593 MHz). x1 + x2 + x3) may be adjusted to 185 to 285 mm (especially 210 to 260 mm). At this time, x1 may be adjusted to 80 to 120 mm (particularly 90 to 110 mm), x2 may be adjusted to 5 to 25 mm (particularly 10 to 20 mm), and x3 may be adjusted to 100 to 140 mm. (In particular, it may be adjusted to 110 to 130 mm).

In the present invention, when the wavelength in the air at the center frequency of the broadcast frequency band to be received is λ ₀ , the glass wavelength shortening rate is k (where k = 0.64), and λ _g = λ ₀ · k. The conductor length L1 from the starting point on the antenna element 2 to the end point where the extension stops after extending in the right direction (corresponding to x4 in FIGS. 1 and 2 and (x4a + x4b + x4c in FIGS. 3 and 4)) 5 and 6 (corresponding to x4aa (x4ab)) is (3/64) λ _g to (14/64) λ _g (in particular, (6/64) λ _g to (13/64). ) Λ _g ) is preferable in terms of improving the antenna gain in the broadcast frequency band.

Therefore, for example, when it is desired to improve the antenna gain of the terrestrial digital television broadcasting band (473 to 713 MHz), the center frequency of the terrestrial digital television broadcasting band (473 to 713 MHz) is about 600 MHz (strictly 593 MHz). Is preferably adjusted to 15 to 70 mm (particularly 30 to 65 mm).

In the present invention, when the wavelength in the air at the center frequency of the broadcast frequency band to be received is λ ₀ , the glass wavelength shortening rate is k (where k = 0.64), and λ _g = λ ₀ · k. The horizontal component distance xs1 between the antenna conductor end on the leftmost side of the antenna element 3 and the parasitic conductor end on the rightmost of the elements forming the parasitic conductor is − (5/64) λ _g It is preferable that ˜ (1/64) λ _g (particularly − (4/64) λ _g ˜ (1/64) λ _g ) is obtained in terms of improving the antenna gain in the broadcast frequency band. .

Here, the leftmost antenna conductor end of the antenna element 3 corresponds to the terminal end 3g in the case of FIG. 1 or the like, and corresponds to the constituent element 3b of the additional element in the case of FIG. The parasitic conductor end on the rightmost side of the elements forming the parasitic conductor corresponds to the terminal end 6g in the case of FIG. 1 and the like, and corresponds to the parasitic element 5 in the case of FIG. In the case of FIG. 8, this corresponds to the terminal end 6rg.

Also, for the positive and negative signs of xs1, the position of the parasitic conductor end is on the right side with respect to the virtual straight line 21 that passes through the leftmost antenna conductor end and is parallel to the second direction. It is positive, and the case where it is on the left side with respect to the virtual straight line 21 is negative.

Therefore, for example, when it is desired to improve the antenna gain of the terrestrial digital television broadcasting band (473 to 713 MHz), the center frequency of the terrestrial digital television broadcasting band (473 to 713 MHz) is about 600 MHz (strictly 593 MHz), so xs1 Is adjusted to −25 to 5 mm (particularly −20 to 5 mm).

As described above, the terrestrial digital TV broadcasting band in Japan has been described as an example, but it is also suitable for receiving terrestrial digital TV broadcasting bands in other countries, and is a broadcasting frequency band that is received within a range of 470 to 862 MHz. If there is, it functions suitably as a glass antenna.
1 to 8 show examples in which the glass antenna is arranged on the window glass 12. A vehicle body opening edge 15 a on the upper side of the vehicle body is arranged in the upper region of the window glass 12. By reducing the size of the glass antenna, a defogger (not shown) is formed in the central region of the window glass 12, so that even if the upper region of the window glass 12 becomes narrow, it can be easily arranged in the narrow region. . Moreover, you may arrange | position in the center upper area | region of the window glass 12, a center left area | region, a center right area | region, and a lower area | region.

Further, in the present invention, when the glass antenna is disposed in the upper left region of the window glass 12 in the form of FIGS. 1 to 8, the upper right region of the window glass 12 is symmetrical to the form of FIGS. It may be arranged. The same applies to the lower region. When a plurality of glass antennas are installed as described above, diversity reception is achieved and reception characteristics are improved, which is preferable.

Also, a glass antenna may be formed by providing a conductor layer made of an antenna conductor inside or on the surface of a synthetic resin film, and forming a synthetic resin film with a conductor layer on the inside or outside surface of the window glass plate. Furthermore, it is good also as a glass antenna by forming the flexible circuit board in which the antenna conductor was formed in the vehicle inner surface or vehicle outer surface of a window glass board.

The angle of the window glass attached to the vehicle is preferably 15 to 90 °, particularly 30 to 90 ° with respect to the horizontal direction.

Further, a concealing film may be formed on the surface of the window glass, and a part or the whole of the antenna conductor may be provided on the concealing film. The concealing film may be a ceramic such as a black ceramic film. In this case, when viewed from the outside of the window glass, the portion of the antenna conductor provided on the masking film by the masking film becomes invisible from the outside of the vehicle, and the window glass has an excellent design. In the configuration shown in the drawing, at least a part of the feeding part, the ground part, the antenna conductor, and the parasitic conductor is formed on the concealment film, so that only a thin straight line part of the conductor is seen in the vehicle external view, which is preferable in terms of design. .

A description will be given of measurement results such as frequency characteristics and directivity characteristics of an automotive high-frequency glass antenna manufactured by attaching the glass antenna shown in FIG. 1 to the upper left side of an actual vehicle windshield when viewed from inside the vehicle. FIG. 11A is a schematic diagram of a feeding structure of a glass antenna 100 according to the present invention, and FIG. 11B is a schematic diagram of a feeding structure of a conventional glass antenna X (Japanese Patent Laid-Open No. 2007-110390). The glass antenna 100 is suitable for reception of radio waves in a high frequency band, but is particularly suitable for reception of a terrestrial digital television broadcast band (470 to 770 MHz). The dimensions of each part of each glass antenna are the values shown in FIGS. 11A and 11B (unit: mm).

The conductor width of each element is 0.8 mm. The sizes of the power feeding unit 16A and the ground unit 16B are the same. The same applies to other figures described later.

In the case of FIG. 11A, the inner conductor of the coaxial cable connected to the signal processing circuit is connected to the power feeding section 16A, and the outer conductor is grounded to the vehicle body. The ground portion 16B is also grounded to the vehicle body. In the case of FIG. 11B, the inner conductor of the coaxial cable connected to the signal processing circuit is connected to the power feeding portion, and the outer conductor is grounded to the vehicle body. That is, in the case of the feeding structure shown in FIG. 11A, the parasitic conductor of the glass antenna 100 is grounded to the vehicle body, whereas in the case of the feeding structure shown in FIG. 11B, the parasitic conductor of the glass antenna X is grounded to the vehicle body. Not connected.

The antenna gain was measured by radiating radio waves to a vehicle mounted with the window glass inclined at 15 ° with respect to the horizontal direction, and rotating the vehicle 360 ° every angle of 3 °. The radio wave was horizontally polarized, and the frequency was changed every 6 MHz in the range of 473 to 713 MHz. The elevation angle between the radio wave transmission position and the antenna conductor was measured in the horizontal direction (when the plane parallel to the ground is elevation angle = 0 ° and the zenith direction is elevation angle = 90 °, the elevation angle = 0 °). The antenna gain was standardized so that the half-wave dipole antenna was 0 dB with reference to the half-wave dipole antenna.

FIG. 12 is a frequency characteristic diagram of the antenna gain of the glass antenna 100 and the glass antenna X. FIG. In the frequency characteristics diagram of the antenna gain, the antenna gain on the vertical axis indicates the average value of the antenna gain measured every 3 ° by rotating the vehicle 360 ° (the antenna for every 6 MHz at all frequencies 473 to 713 MHz). Average gain). The same applies to other figures described later.

FIG. 13 is a directivity characteristic diagram of the directivity of the glass antenna 100 and the glass antenna X for each reception frequency. The directivity characteristic diagram represents the directivity characteristic of the glass antenna attached to the windshield over the entire circumference of the vehicle, and shows the average value of the antenna gain for every 6 MHz in every frequency of 473 to 713 MHz every 3 °. In the drawing, the upper half corresponds to the front area of the vehicle, and the lower half corresponds to the rear area of the vehicle.

Table 1 summarizes the data of FIGS. When the average gain in all frequency bands of 473 to 713 MHz is calculated, the glass antenna 100 is −3.5 dB, the glass antenna X is −3.5 dB, and the average gain in all frequency bands is the same as the conventional gain. Secured. On the other hand, when the F / B ratio is calculated, the glass antenna 100 is 6.0, the glass antenna X is 9.1, and the glass antenna 100 has a smaller difference in sensitivity between the front and the rear of the vehicle than in the past. Further, FIG. 13 shows that the antenna gain in the vehicle width direction is superior to the conventional glass antenna X.

The F / B ratio is -90 ° to + 90 ° in the horizontal direction (front side of the vehicle) when the vehicle front is 0 “zero” °, the vehicle left is + 90 °, and the vehicle rear is + 180 °. The difference between the average antenna gain (every 1 °) and the average antenna gain (every 1 °) of + 90 ° to + 270 ° (on the rear side of the automobile) in the horizontal direction.

If the F / B ratio is small, the difference in antenna gain between the front direction of the vehicle and the rear direction of the vehicle is small, and the directivity is close to omnidirectional in the horizontal direction. On the other hand, if the F / B ratio is large, it has a strong directivity in the front direction of the automobile. The area average calculation method was applied to the calculation of the average antenna gain.

Also, the horizontal width of the glass antenna 100 of FIG. 11A is 190 (= 30 + 5 + 120 + 35) mm, whereas the horizontal width of the glass antenna X of FIG. 11B is 200 (= 140-60 + 120) mm. Therefore, the glass antenna 100 is smaller than the conventional glass antenna X.

FIG. 14 shows measured data of antenna gain when the conductor length x4 is changed in the glass antenna 100 having the pattern of FIG. In order to confirm the effect of the conductor length x4, the glass antenna 100 when the data shown in FIG. 14 is actually measured is not provided with a ground portion and a parasitic conductor. When the conductor length x4 is zero, it indicates that there is no antenna element 4, and x4 increases as it extends in the right direction.

The dimensions of each part of the glass antenna 100 shown in FIG.
x1: 100 mm
x2: 10 mm
x3: 120 mm
And

As shown in FIG. 14, in the case of the terrestrial digital television broadcasting band (470 to 770 MHz), the conductor length x4 is 15 mm to 70 mm (particularly, 30 mm to 65 mm), which improves the antenna gain. This is preferable.

15 shows a pattern in which the antenna element 4 is not provided in the glass antenna 100 shown in FIG. 1, when the overlap distance xs1 in the horizontal direction between the terminal end 3g and the terminal end 6g is changed. It is actual measurement data of antenna gain. When the overlap distance xs1 on the horizontal axis is a positive value, the two elements 3 and 6 are in a positional relationship in which the vertical projection of one element overlaps the other element. On the other hand, when the overlap distance xs1 is a negative value, it indicates that there is a non-overlapping positional relationship. That is, when the value is positive, it indicates that the antenna element 3 and the parasitic element 6 overlap each other. When the value is negative, there is a gap in the horizontal direction between the terminal end 3g and the terminal end 6g. Represents something. When x6 is 35 mm, xs1 is zero.

The dimensions of each part of the glass antenna 100 when measuring the data of FIG.
x1: 100 mm
x2: 10 mm
x3: 120 mm
x4: 0 mm
x5: 15 mm
And

As shown in FIG. 15, the antenna gain is improved when the vertical projections of the elements 3 and 6 do not overlap each other. For example, in the case of a terrestrial digital television broadcast band (470 to 770 MHz), the horizontal gap between the terminal end 3g and the terminal end 6g is −25 to 5 mm (particularly −20 to 5 mm). From the viewpoint of improving the antenna gain.

FIG. 16 is a frequency characteristic diagram of the antenna gain of the glass antennas 100 to 600. FIG. The change in antenna gain due to the difference in the antenna conductor pattern of the glass antenna according to the present invention was compared.

The dimensions of the antenna conductor of each glass antenna shown in FIGS.
x1: 100 mm
x2: 10 mm
x3: 120 mm
x3a: 100 mm
x3b: 5 mm
x3c: 25 mm
x4: 30 mm
x4a: 20 mm
x4b: 10 mm
x4c: 10 mm
x4aa: 30 mm
x4ab: 30 mm
And

The dimensions of the parasitic conductor of each glass antenna shown in FIGS. 1 to 6 are equal between the glass antennas.
x5: 15 mm
x6: 30 mm
And

Table 2 summarizes the data of FIG. When the average gain in the entire frequency band of 473 to 713 MHz is calculated, the average gain of the glass antenna 100 in the entire frequency band is the highest.

Further, the glass antennas 100 to 600 are reduced in size while ensuring an antenna gain equivalent to that of the conventional glass antenna X (see Table 1).

FIG. 17 is a frequency characteristic diagram of the antenna gain of the glass antennas 100A, 100B, 700 to 900. The change of the antenna gain by the difference in the pattern of the parasitic conductor of the glass antenna according to the present invention was compared. The difference between 100A and 100B is the conductor length x5 of the parasitic element 5 in the form of the glass antenna 100 shown in FIG.

The dimensions of the antenna conductor of each glass antenna shown in FIGS.
x1: 100 mm
x2: 10 mm
x3: 120 mm
x3: 150 mm (in the case of glass antenna 700)
x4: 30 mm
And

The dimensions of the parasitic conductor of each glass antenna shown in FIGS.
x5: 15 mm
x5: 10 mm (in the case of glass antenna 100B)
x5: 0 mm (for glass antenna 900)
x6: 30 mm
x6: 40 mm (in the case of glass antenna 800)
x6l: 20 mm (in the case of glass antenna 800)
x6r: 20 mm (for glass antenna 800)
x6: 0 mm (for glass antenna 900)
And

Table 3 summarizes the data of FIG. When the average gain in the entire frequency band of 473 to 713 MHz is calculated, all of the average gains of the glass antennas 100A, 100B, 700, and 800 are higher than those of the glass antenna 900 having no parasitic conductor.

Therefore, by providing a feeding structure for grounding the parasitic conductor to the vehicle body in an antenna configuration such as the glass antenna 100 to 800, the antenna pattern can be reduced in size while ensuring excellent antenna characteristics covering a wide band. Further, by attaching the glass antennas 100 to 800 to the windshield or rear glass, it is possible to increase the reception sensitivity of radio waves from the vehicle width direction. Furthermore, by attaching the glass antennas 100 to 800 to both the windshield and the rear glass, a substantially round directional antenna characteristic centered on the vehicle can be obtained, and the reception sensitivity of radio waves from the vehicle width direction can be increased. it can.

Although this application has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on a Japanese patent application filed on April 16, 2009 (Japanese Patent Application No. 2009-100213), the contents of which are incorporated herein by reference.

The present invention receives terrestrial digital TV broadcasts, UHF analog TV broadcasts and US digital TV broadcasts (698-806 MHz), European Union digital TV broadcasts (470-862 MHz) or People's Republic of China digital TV broadcasts. Used for automotive glass antennas. In addition, Japanese FM broadcast band (76-90 MHz), US FM broadcast band (88-108 MHz), TV VHF band (90-108 MHz, 170-222 MHz), 800 MHz band for automobile telephones (810-960 MHz), automobile 1.5 GHz band for telephone (1.429 to 1.501 GHz), UHF band (300 MHz to 3 GHz), GPS (Global Positioning System), artificial satellite GPS signal 1575.42 MHz), VICS (registered trademark) (Vehicle Information and Communication System: 2.5 GHz).

Furthermore, ETC communication (Electronic Toll Collection System: non-stop automatic toll collection system, roadside wireless device transmission frequency: 5.795 GHz or 5.805 GHz, roadside wireless device reception frequency: 5.835 GHz or 5.845 GHz), dedicated narrow Area communication (DSRC: Dedicated Short Range Communication, 915 MHz band, 5.8 GHz band, 60 GHz band), microwave (1 GHz to 3 THz), millimeter wave (30 to 300 GHz), automotive keyless entry system (300 to 450 MHz), and And SDARS (Satellite Digital Audio Radio Service IV (2.34 GHz, 2.6 GHz)).

1 to 4 Antenna elements 5, 6 Parasitic element 11 Car body panel 11a Inner panel 11b Outer panel 12 Window glass 13 Adhesive 14 Antenna unit 15a Car body opening edge 16A Feeding part 16B Grounding part 18 Amplifier case 19 Amplifier case 18 Internal 20 Signal processing circuit 21 Virtual straight line 22 Insulating sheet 23 Base member 24 Cover 26 Nut 27 Bolt 28A, 28B Holder 29A First joint member 29B Second joint member 30A First joint member 30B Second joint member 31 Elasticity Connecting member 32 Paint film 33 Elastic plate 34 Connecting portion 35 Metal plate 36 Convex portion 100 to 800 Glass antenna for vehicle (with parasitic conductor)
900 Glass antenna for vehicles (no parasitic conductor)
X Conventional glass antenna for vehicles (with parasitic conductor)

Claims (15)

1. In the vehicle glass antenna in which the antenna conductor, the feeding portion connected to the antenna conductor, the parasitic conductor, and the ground portion connected to the parasitic conductor are provided on the window glass,
   When the window glass is mounted on a vehicle, the power feeding unit is a part for electrically connecting the antenna conductor to a signal processing circuit mounted on the vehicle, and the ground unit is connected to the vehicle body. It is a part for electrically connecting the feeding conductor,
   The power feeding part and the ground part are arranged side by side along a reference direction,
   The antenna conductor is
   A first element extending in a first direction which is a direction parallel to the reference direction and toward the opposite side of the ground portion, starting from the power supply portion;
   A second end that is connected to a first end portion that is the end opposite to the power feeding portion of the first element, is orthogonal to the first element and is directed inward with respect to the outer periphery of the window glass. A second element extending in the direction;
   A third element extending from the second element as a starting point in a third direction which is a direction opposite to the first direction;
   The glass antenna for a vehicle according to claim 1, wherein the parasitic conductor includes a parasitic element that is an element extending at least partially in the second direction from the ground portion.
2. The antenna conductor is
   The glass antenna for vehicles according to claim 1 provided with the 4th element extended in said 1st direction from said 2nd element as the starting point.
3. The glass antenna for a vehicle according to claim 2, wherein a plurality of the fourth elements are extended in the first direction starting from the second element.
4. The fourth element extends in the first direction, then extends in a direction opposite to the second direction or the second direction, and is further folded back and extended toward the third direction. The glass antenna for vehicles according to claim 2 or 3 provided with a return part.
5. When the wavelength in the air at the center frequency of the broadcast frequency band to be received is λ ₀ , the glass wavelength reduction rate is k (where k = 0.64), and λ _g = λ ₀ · k,
   The conductor length of the fourth element, (3/64) lambda _g or more (14/64) is lambda _g or less, a vehicle glass antenna according to any one of claims 2 to 4.
6. The parasitic conductor is
   The glass antenna for vehicles according to any one of claims 1 to 5 provided with an attachment parasitic element parallel to said reference direction and connected to said parasitic element.
7. When the wavelength in the air at the center frequency of the broadcast frequency band to be received is λ ₀ , the glass wavelength reduction rate is k (where k = 0.64), and λ _g = λ ₀ · k,
   The sum of the conductor length of the parasitic element and the accessory parasitic element, (4/64) lambda _g or more (13/64) is lambda _g or less, a vehicle glass antenna according to claim 6.
8. When the wavelength in the air at the center frequency of the broadcast frequency band to be received is λ ₀ , the glass wavelength reduction rate is k (where k = 0.64), and λ _g = λ ₀ · k,
   The sum of the conductor lengths of the first element, the second element, and the third element is (37/64) λ _g or more and (57/64) λ _g or less. The glass antenna for vehicles as described in any one.
9. The third element extends in the third direction, then extends in the direction opposite to the second direction or the second direction, and is further folded and extended toward the first direction. The glass antenna for vehicles according to any one of claims 1 to 8 provided with an additional element part.
10. The first portion between the antenna conductor end portion closest to the third direction of the third element and the parasitic conductor end portion closest to the first direction among the elements forming the parasitic conductor. The distance of one direction component is
    When the position of the parasitic conductor end is on the first direction side with respect to a virtual straight line passing through the antenna conductor end and parallel to the second direction,
    When the position of the parasitic conductor end is on the third direction side with respect to the virtual straight line is negative,
    The glass antenna for a vehicle according to any one of claims 1 to 9, wherein the glass antenna is -25 mm or more and 5 mm or less.
11. The vehicle glass antenna according to any one of claims 1 to 10, wherein a broadcast frequency band to be received is in a range of 470 to 862 MHz.
12. A vehicle window glass comprising the vehicle glass antenna according to any one of claims 1 to 11.
13. The vehicle window glass according to claim 12, wherein the grounding portion includes a second conductive member that electrically connects the grounding portion to the vehicle body.
14. The vehicle window glass according to claim 12 or 13, wherein the second conductive member is configured such that a conductor length from the ground portion to the vehicle body is 50 mm or less.
15. The vehicle window glass according to claim 12,
    A first conductive member for electrically connecting the power feeding unit to the signal processing circuit;
    A power supply structure for a glass antenna for a vehicle, comprising: a second conductive member that electrically connects the ground portion to a vehicle body.

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