JPH0738318A - Glass antenna for vehicle - Google Patents

Abstract

PURPOSE:To prevent receiving energy energy from leaking from an internal conductor of a coaxial cable, and to improve the receiving sensitivity by shielding a feeding part, the vicinity of the feeding part and the tip part of the coaxial cable with a metallic case. CONSTITUTION:On a windowpane plate 1, an antenna conductor 30 of a prescribed pattern is provided, and in the vicinity of a feeding part of the antenna conductor 30, a ground conductor 4 of a prescribed pattern is provided. Also, an internal conductor 51 of a coaxial cable 50 and the antenna conductor 30, and an external conductor 52 and a ground conductor 4 are connected with solder, a conductive adhesive agent, a brazing filler metal, etc. The coaxial cable 50 is extended to a receiver, an amplifier circuit, a resonance circuit, etc., and a receiving signal transmitted to the internal conductor 51 is sent to the receiver, etc. In this glass antenna for a vehicle, the feeding part, the vicinity of the feeding part and the tip part of the coaxial cable 50 are shielded with a metallic case 7. The metallic case 7 is insulated from the antenna conductor 30 by air or an insulator, and also, contributes to improvement of a receiving characteristic, when it is provided right under the feeding part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle glass antenna suitable for the UHF band.

[0002]

2. Description of the Related Art Conventionally, automobiles used in the UHF band
Various glass antenna structures have been proposed in the fields of mobile phones, train / aircraft phones, and satellite communications. In either case, a coaxial cable is directly attached as a power feeding system from the antenna, or a simple structure in which, for example, a BNC type or SMB type high frequency coaxial connector is used.

However, with such a structure, there is a drawback that the transmission energy of the reception signal excited in the glass antenna leaks from the inner conductor of the coaxial cable attached near the feeding portion of the glass antenna and the reception sensitivity is lowered. there were.

[0004]

SUMMARY OF THE INVENTION The present invention aims to overcome the above-mentioned drawbacks of the prior art, and provides a novel glass antenna for a vehicle, which has not been heretofore known.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. "An antenna conductor having a predetermined pattern is provided on a window glass plate of a vehicle, and the predetermined pattern is provided in the vicinity of a feeding portion of the antenna conductor. In the glass antenna for a vehicle, the ground conductor of the coaxial cable is connected to the inner conductor of the coaxial cable, and the outer conductor of the coaxial cable is connected to the ground conductor. The vehicle glass antenna is characterized in that the above is shielded by a metal box.

The present invention also provides the "glass antenna for a vehicle, wherein the metal box is grounded".

The present invention also provides the "glass antenna for a vehicle, wherein the grounding conductor is grounded to the vehicle body".

[0008]

[Embodiment 1] FIG. 1 is a side view of a vehicle glass antenna of the embodiment, and FIG. 2 is a plan view of the embodiment.
1 and 2, 1 is an automobile window glass plate, 30 is an antenna conductor, 4 is a ground conductor, 50 is a coaxial cable, 5
1 is an inner conductor of the coaxial cable 50, 52 is an outer conductor of the coaxial cable 50, and 6 is a conductive adhesive made of solder or the like for connecting the inner conductor 51 and the antenna conductor 30 at a feeding portion of the antenna conductor 30. Reference numeral 7 indicates a metal box.

As shown in FIGS. 1 and 2, in the structure of the glass antenna for vehicle of the embodiment, the antenna conductor 30 having a predetermined pattern is provided on the window glass plate 1, and the antenna conductor 30 is provided.
A ground conductor 4 having a predetermined pattern is provided in the vicinity of the power feeding portion.

The inner conductor 51 and the antenna conductor 30 of the coaxial cable 50, and the outer conductor 52 and the ground conductor 4 are bonded and connected with solder, a conductive adhesive, a brazing material or the like, respectively.
The coaxial cable 50 is extended to a receiver, an amplifier circuit, a resonance circuit, etc., and the reception signal transmitted to the internal conductor 51 is sent to the receiver etc.

The metal box 7 is insulated from the antenna conductor 30 by air or an insulator, and if it is provided directly below the power feeding portion, it contributes to the improvement of the reception characteristics. However, the size of the metal box 7 is larger than that of the metal box 7. In the case of a circular shape, it is more preferable that the distance between the feeding point and the radius is 10 mm at least around the feeding point, and it is particularly preferable that the distance reaches just above the ground conductor 4. It is desirable from the viewpoint of reception characteristics that the metal box 7 is not provided on the antenna conductor 30 as much as possible. The area of the metal box 7 is
It is not limited to FIG. 2 and may be determined according to the specifications.

Further, the distance between the metal box 7 and the feeding portion, that is, the distance between the edge 8 of the metal box 7 and the antenna conductor 30 is 1 to
3 mm is preferable. If it is less than 1 mm, the antenna conductor 3
A leak occurs from 0 to the metal box 7 and the reception sensitivity is reduced.

Further, although the metal box 7 improves the receiving characteristics to some extent even if it is not grounded, it is more desirable if it is grounded to the body of the vehicle. In the embodiment, the metal box 7 is connected and grounded at a portion where the edge of the metal box 7 and the ground conductor 4 intersect. The shape of the metal box 7 is not limited to that shown in FIG. 2, and may be another shape such as a circle, an ellipse, a trapezoid, or a rhombus as long as the above requirements are satisfied.

In the embodiment, the ground conductor 4 is used in a state where it is not grounded to the body on or near the window glass plate 1, but it can also be used by being directly grounded or capacitively coupled to the body. In the embodiment, the external conductor 52 connected to the ground conductor 4 is grounded on the receiver side.

Further, it is desirable that the area of the ground conductor 4 is larger in view of reception characteristics, but there are certain restrictions due to factors such as aesthetics and visual field. The shape is not limited to that shown in FIG. 2 and may be a circle, an ellipse, a trapezoid, a rhombus, or the like.

The antenna conductor 30 and the ground conductor 4 are obtained by forming silver paste on the window glass plate 1 by printing and firing it. However, the present invention is not limited to this, and a metal box, a metal plate or the like can be used for the window glass plate 1.
It may be adhered or the like on top. In the embodiment, the shape of the antenna conductor 30 is substantially triangular as shown in FIG. 2, but the shape is not limited to this, and a shape in which several antenna wires are radially extended from the feeding portion, a rhombus, a trapezoid, a circle, It may be oval or the like. The antenna length of the example is about 75 mm.

In FIG. 2, the antenna structure combined with the antenna conductor 30 and the ground conductor 4 conforms to a Brown (ground plane) antenna in which the current distribution is maximized near the feeding point. Further, by the ground conductor 4, 31 patterns shown by the broken line in the figure (the antenna 3 by the electric image method)
An antenna image image of 0) is created, and the antenna becomes a dipole twin fan antenna.

Therefore, by surrounding the antenna feeding portion with the metal box 7, there is an effect that the above-mentioned antenna image image 31 is easily formed, and the gain of the antenna is improved. Further, as described above, the leakage of the transmission energy in the vicinity of the feeding point of the antenna is suppressed, which contributes to the gain improvement. Regarding the reception characteristic of the embodiment, the carrier frequency 84
2d at 0MHz compared to the case without metal box 7
B or more improved.

[Embodiment 2] FIG. 3 is a side view showing a case where a coaxial cable is connected to a power feeding portion and a ground conductor through a connector. In the figure, 50 is a coaxial cable, 3 is a plug, 4 is a receptacle, 9 and 10 are positive and negative electrodes of the receptacle, and 7 is a metal box. In the second embodiment, like the first embodiment, leakage waves are prevented, an antenna image image is produced by an electric image method, and it is useful for improving the antenna gain, and by using the plug 3 and the receptacle 2, the standing wave ratio is small. Becomes, coaxial cable 50 and antenna conductor 3
The match of 0 is better. In Example 2, the standing wave ratio was 1.2.

[0020]

According to the present invention, the energy of the received signal excited by the metal box from the inner conductor of the coaxial cable to the antenna conductor is unlikely to leak to the outside, and the reception characteristic, particularly the reception sensitivity, is remarkably improved. .

[Brief description of drawings]

FIG. 1 is a side view of a glass antenna according to a first embodiment.

FIG. 2 is a plan view of the glass antenna according to the first embodiment.

FIG. 3 is a side view of the glass antenna according to the second embodiment.

[Explanation of symbols]

 1: Window glass plate 7: Metal box 30: Antenna conductor 4: Ground conductor 50: Coaxial cable 51: Inner conductor 52: Outer conductor

Claims (3)

[Claims] 1. A coaxial cable, wherein an antenna conductor having a predetermined pattern is provided on a window glass plate of a vehicle, and a ground conductor having a predetermined pattern is provided in the vicinity of the feeding portion of the antenna conductor, and the inner conductor of the coaxial cable is connected to the feeding portion. In the glass antenna for a vehicle, which is formed by connecting the outer conductor of the above to a ground conductor, the glass portion for a vehicle, characterized in that the feeding portion, the vicinity of the feeding portion and the tip of the coaxial cable are shielded by a metal box. 2. The glass antenna for a vehicle according to claim 1, wherein the metal box is grounded. 3. The glass antenna for a vehicle according to claim 1, wherein the ground conductor is grounded to the body of the vehicle.