JPH077318A - Window glass antenna - Google Patents

Abstract

PURPOSE:To improve the field of vision, to save the space and to improve fitting work. CONSTITUTION:A divercity window glass antenna 1 is constituted by arranging a monopole antenna on one face 2a of a film 2 folding into two and a spectacles-type antenna 4 on another face 2b. On the other hand, the monopole side face is stuck to an inclined window glass face 7, and the spectacles-type face is folded almost perpendicularly. Thus, since the directivity of two antennas is made different each other almost at 90 deg., a divercity effect is improved even when those antennas are adjacently arranged and since the monopole side to hardly change reception sensitivity corresponding to the fitting angle is fitted on the slope and the spectacles-type side to most improve sensitivity in the case of making the fitting angle almost perpendicular is fitted almost perpendicularly, reception sensitivity is improved as well. Further, since it is enough only to stick the face of one film to window glass, the field of vision is improved, the space is saved and fitting work can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a window antenna mounted on a window glass of an automobile, and more particularly to improvement of a diversity antenna.

[0002]

2. Description of the Related Art A so-called diversity antenna having a plurality of antennas that resonate at the same frequency and any one of the antennas is selectively connected to a transmitting or receiving apparatus is known.

As a conventional diversity antenna for an automobile telephone, for example, a rod antenna attached to the outside of the vehicle body and having two antennas at the top and bottom, and two antennas provided inside the automobile such as a rear tray are provided. Antenna boxes and the like are known. However, in the case of the bar antenna, the mounting work is complicated because it is mounted outside, and in the case of the antenna box, a dedicated space for providing this is required. Therefore, it was considered to arrange two sets of antenna patterns on the window glass and use them as diversity antennas.

A window glass antenna in which an antenna pattern is provided on a film and the film is attached to a window glass of an automobile is also known.

By the way, in a car telephone, the frequency is 8
Since the ultra high frequency band (UHF) such as the 00 MHz band is used, it is necessary to dispose not only the radiation pattern but also the ground pattern on the window glass. Also, the frequency is about 800
Since it is as high as MHz, it was necessary to widen the width of each pattern.

The three window glass antennas filed by the present applicant as conventional antennas of this type will be described. First, FIG. 7 shows a pattern diagram of a monopole antenna (Japanese Patent Application No. 4-38628). This monopole antenna 80
In the above, the radiation pattern 81 is arranged in the vertical direction of the glass surface, and the hollow grounding pattern 82 is arranged below. The feeding point 81a is provided at the lower end of the radiation pattern 81, and the grounding point 82a is provided at the center of the upper end of the grounding pattern 82.

Next, an eyeglass-type antenna (Japanese Patent Application No. 4-343).
No. 261) is shown in FIG. This spectacle-type antenna 90 is a spectacle-shaped radiation pattern 91 formed by combining two substantially circular patterns 91a and 91b, and a horizontally-long grounding pattern 92 disposed between the connection portions 91c and 91d of the patterns 91a and 91b. It consists of and. Further, both ends of the patterns 91a and 91b have protrusions 91 protruding outward.
e, 91f are formed. Then, the connecting portion 91
A feeding point 91g was provided near d, and a grounding point 91h was provided near the center of the grounding pattern 92.

Next, a half-loop type antenna (actual Kaihei 1-5
FIG. 9 shows a pattern diagram of Japanese Patent No. 7807). This semi-loop type antenna 100 has two semi-circular patterns 101.
a radiation pattern 101 formed by combining a and 101b,
It is composed of a horizontally long ground pattern 102 short-circuited at both ends 101c and 101d of these patterns. And
Connection part 101 of the semicircular patterns 101a and 101b
A feeding point 101f was provided near e, and a grounding point 102a was provided near the center of the grounding pattern 102.

The feeding points 81a, 91g, 10
The core wire of a coaxial cable (not shown) is connected to 1f, the braided wire of the coaxial cable is connected to the ground points 82a, 91h, and 102a, and the other end of the coaxial cable is connected to an antenna terminal of a telephone device for automobiles. It was connected.

A diversity antenna can be constructed by arranging two sets of such antennas on the window glass. In this case, the radiation pattern and the ground pattern are 2
It is necessary to arrange a total of four each.

[0011]

However, the increase in the number of patterns not only hinders the visibility, but also expands the occupied space. Further, since the pattern is arranged on the window glass by printing or the like, it is necessary to print it on the window glass in advance, which is one of the problems in terms of improving workability. Therefore, an object of the present invention is to provide a window glass antenna capable of improving the field of view and saving space and also improving the workability of pattern mounting.

[0012]

According to the present invention, in order to solve the above-mentioned problems, a film is provided in the shape of a letter V in a side view, and antenna patterns having different directivities are arranged on each side of the film. One of the film surfaces was attached to the window glass.

An antenna pattern is provided on the film surface on the side of the window glass so that the receiving sensitivity is less likely to change even if the mounting angle changes, and the receiving sensitivity increases on the other film surface as the mounting angle becomes closer to vertical. A pattern may be provided.

A monopole antenna is used as an antenna pattern in which the receiving sensitivity does not easily change even if the mounting angle changes.
A spectacle-type or half-loop type antenna may be used as an antenna pattern in which the receiving sensitivity increases as the mounting angle becomes closer to vertical.

A material having high transparency may be used as the film.

[0016]

The antenna pattern is provided on each surface of the V-shaped film in a side view, and only one of the surfaces is attached to the window glass, so that the space for one antenna pattern is sufficient. Therefore, it is possible to improve the visibility and save space. Also, if you attach this film to the window glass,
After that, the workability is improved because the antenna installation work is completed simply by connecting the power supply cable. Further, since a set of antennas is composed of antenna patterns having different directivities, the diversity effect can be effectively exhibited even if the patterns are close to each other.

Further, since an antenna is generally attached to an inclined window glass, an antenna whose reception sensitivity is unlikely to change even if the attachment angle changes is used as the antenna on the side of the window glass, and the reception sensitivity becomes closer to the other antenna as it is closer to vertical. If an antenna having a high value is used, the receiving sensitivity can be improved as a whole.

The pattern is simplified by using a monopole antenna as an antenna whose reception sensitivity does not easily change even if the mounting angle changes, and by using a spectacle-type or half-loop antenna as an antenna whose reception sensitivity increases as it gets closer to the vertical. Can be achieved.

If a material having high transparency is used as the film, the field of view can be further improved.

[0020]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram of a first embodiment of a window glass antenna according to the present invention. A window glass antenna 1 according to the present invention includes a half-folded film 2 formed of a relatively thin member such as resin, and a monolayer film 2 disposed on one surface 2 a of the film 2. It is composed of a pole antenna 3 and a spectacle antenna 4 arranged on the other surface 2b of the film 2. Further, power feeding coaxial cables 5 and 6 are connected to the respective antennas 3 and 4 between the power feeding portions and the ground portions.

Further, these antennas 3 and 4 are set to have such a length that they resonate at the same frequency, and the other ends of the cables 5 and 6 are connected through a control box (not shown) to the antenna terminals of one automobile telephone device. Is a diversity antenna connected to.

The monopole antenna 3 and the spectacles-type antenna 4 are the same as the above-described conventional antennas 80 and 90, and the description thereof will be omitted.

In the present embodiment, an 800 MHz band car telephone antenna will be described as an example, but the present invention is not limited to this. Further, the antenna operates as a diversity antenna in the case of reception, and in the case of transmission, the control box controls so that either one of the antennas is selected.

FIG. 2 is an external view showing a state in which the window glass antenna is attached to the window glass. The window glass antenna 1 is mounted, for example, on the lower left side of a rear window glass 7 of an automobile that is inclined about 30 degrees from the vertical (so that the lower side faces the outside of the vehicle). Then, the film 2a side on which the monopole antenna 3 is disposed is attached from the vehicle interior side of the window glass 7 so that the bent portion 2c faces upward. In FIG. 1, the monopole antenna 3 is shown by a solid line for easy understanding of the drawing, but it is correctly shown by a broken line. In this way, the monopole antenna 3 is attached so as to be inclined.

Further, the four corners 2h of the film surface 2a,
Although 2i, 2j, and 2k are attached to the window glass with an adhesive, the present invention is not limited to this. For example, the entire surface of the film 2a may be attached to the window glass.

On the other hand, the film 2b provided with the spectacle-type antenna 4 is not attached to the window glass 7 and is bent substantially vertically from the bent portions 2c of the films 2a and 2b.

When a slightly hard sheet-like material is used as the films 2a and 2b, the mounting angle of the film 2b becomes substantially vertical after the film 2a is attached to the window glass 7. Can be adjusted as

When soft films 2a and 2b are used, the lower ends of the films 2b are fixed by, for example, surface fasteners so that the mounting angle does not change due to vibration of the vehicle during running. Can be fixed to the rear tray of the car.

Although a film obtained by folding one film in two was used as the film, two films may be connected in a V shape.

FIG. 3 is a directivity characteristic diagram of the glasses-type antenna 4, and FIG. 4 is a directivity characteristic diagram of the monopole antenna 3.

This characteristic diagram is obtained by measuring each antenna alone. That is, each antenna is erected at the center of a circular copper plate having a diameter of 1 m so that the pattern surface forms an angle of 90 degrees with respect to the surface of the copper plate, and the copper plate is raised to a height of 1.
The device was installed at a height of 3 m, and the gain was measured over a 360 degree angle with a predetermined angular interval. The standard dipole antenna was measured with a gain of 0 dBμ.

According to FIG. 3, the spectacle-type antenna 4 is moved in the traveling direction of the vehicle (angle 0 °) or in the opposite direction (angle 180 °).
It has the characteristic that the directivity becomes stronger.

According to FIG. 4, the monopole antenna 3
Has the characteristic that the directivity becomes stronger in the left-right direction with respect to the traveling direction. That is, it has a directivity different from the spectacles type antenna 4 by approximately 90 degrees.

Since the antennas 3 and 4 whose directivities are different from each other by about 90 degrees are arranged on the respective surfaces of the bifold film in this manner, a good diversity effect can be exhibited even when the antennas 3 and 4 are close to each other.

FIG. 5 is a characteristic diagram of the reception sensitivity of the monopole antenna and the spectacle-type antenna versus the antenna installation angle. According to this characteristic diagram, the spectacle-type antenna 4 has a large change in reception sensitivity depending on the antenna installation angle, and the sensitivity increases as the antenna installation angle approaches 90 degrees (vertical).
It can be seen that the monopole antenna 3 has a small change in reception sensitivity depending on the installation angle.

As described above, the monopole antenna 3 whose reception sensitivity is little changed depending on the installation angle is arranged on the film 2a on the window glass 7 side (inclination side), and the installation angle is about 90.
Since the spectacle-type antenna 4 having the highest reception sensitivity in the case of the second degree is arranged on the other film (the substantially vertical side) 2b,
Both antennas 3 and 4 can be operated with high reception sensitivity.

That is, according to this structure, a diversity antenna having a high diversity effect and a high reception sensitivity can be realized.

Further, since it is realized by simply attaching one surface of the film having the antenna pattern to the window glass,
The visibility can be improved, the space occupied by the window glass can be reduced, and the workability of attaching the antenna can be improved.

Even if the conventional half-loop type antenna described above is used instead of the spectacle-type antenna 3, the characteristics close to those of the spectacle-type antenna can be obtained.

FIG. 6 is a schematic configuration diagram of the second embodiment. In the window glass antenna 10, the monopole antenna 3 is arranged on the first surface 11a of the film 11 which is folded in three, and the eyeglass-type antenna 4 is arranged on the second surface 11b. Is connected. Then, if the first surface 11a is attached to the window glass, both the diversity effect and the reception sensitivity can obtain the same performance as that of the window glass antenna 1.

Further, in the case of being formed into three folds in this way, the third surface 11c (bottom surface) can be attached to, for example, a rear tray (not shown) or the like to further improve the field of view. Further, there is an effect that it is easy to keep the angles of the first surface and the second surface constant.

In the case of the film 11 as well, one film may not be folded in three, but three films may be connected to each other, or a two-fold film and one film may be connected. But needless to say.

Further, if a material having a relatively high transparency such as glass epoxy resin is used for the films 2 and 11, the field of view can be further improved.

[0044]

EFFECTS OF THE INVENTION Since the antenna pattern is provided on each surface of the V-shaped film in side view, and only one surface is attached to the window glass, the space for one antenna pattern is sufficient. . Therefore, it is possible to improve the visibility and save space. Further, since the arrangement of the antenna pattern is completed only by attaching this film to the window glass, workability is also improved. Moreover, since the antenna patterns having different directivities are combined, the diversity effect can be exhibited even if the patterns are close to each other.

Since the window glass is generally attached to the body in a tilted state, an antenna whose reception sensitivity is unlikely to change even if the attachment angle changes is used as the antenna on the side of the window glass, and the reception sensitivity becomes closer to the other antenna as it is closer to vertical. If an antenna having a high value is used, the receiving sensitivity can be improved as a whole.

Simplification of the pattern by using a monopole antenna as an antenna whose reception sensitivity does not easily change even if the mounting angle changes, and using a spectacle-type or half-loop antenna as an antenna whose reception sensitivity increases as it approaches vertical. Can be achieved.

The visibility can be further improved by using a material having high transparency as the film.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a first embodiment of a window glass antenna according to the present invention.

FIG. 2 is an external view showing a state in which the window glass antenna is attached to the window glass.

FIG. 3 is a directivity characteristic diagram of an eyeglass-type antenna that constitutes the window glass antenna.

FIG. 4 is a directivity characteristic diagram of a monopole antenna that constitutes the window glass antenna.

FIG. 5 is a reception sensitivity vs. antenna installation angle characteristic diagram of a monopole antenna and a glasses-type antenna that compose the window glass antenna.

FIG. 6 is a schematic configuration diagram of a second embodiment of the window glass antenna.

FIG. 7 is a pattern diagram of a conventional monopole antenna.

FIG. 8 is a pattern diagram of the glasses-type antenna.

FIG. 9 is a pattern diagram of the same half-loop type antenna.

[Explanation of symbols] 1 window glass antenna 2 film 2a film surface 2b film surface 3 monopole antenna pattern 4 eyeglass type antenna pattern 7 rear window glass 10 window glass antenna 11 film 11a film surface 11b film surface

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoshiro Okamoto 1 Toyota-cho, Toyota-shi, Aichi Toyota Automobile Co., Ltd.

Claims (4)

[Claims] 1. A film is provided in a V shape in a side view, antenna patterns having different directivities are provided on each surface of the film, and one of the film surfaces is attached to a window glass. Window glass antenna. 2. An antenna pattern is provided on the film surface on the window glass side so that the receiving sensitivity does not easily change even if the mounting angle changes, and the receiving sensitivity becomes higher as the mounting angle becomes closer to vertical on the other film surface. The window glass antenna according to claim 1, further comprising: 3. A monopole antenna is used as an antenna pattern whose reception sensitivity is unlikely to change even when the mounting angle changes, and a spectacle-type or half-loop antenna is used as an antenna pattern whose reception sensitivity increases as the mounting angle approaches vertical. The window glass antenna according to claim 2, which is used. 4. The window glass antenna according to claim 1, wherein a material having high transparency is used as the film.