JPH06276008A - Windshield glass antenna system for automobile telephone - Google Patents

Abstract

PURPOSE:To reduce the mixing of a noise from other electronic equipment such as a radio receiver and a television image receiver mounted on an automobile with a signal reaching an antenna for automobile telephone. CONSTITUTION:A ground-side conductor (external conductor) 4a is grounded to the automobile body by using grounding metallic fittings 5, etc., by stripping a halfway part of the jacket of a coaxial feeder cable 4 which connects the antenna 3 for automobile telephone arranged on the windshield glass 2 of the automobile to an automobile telephone set.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a window glass antenna device for an automobile telephone, in which noise contamination is reduced by connecting a vehicle body ground at an intermediate portion of a power feeding cable.

[0002]

2. Description of the Related Art The applicant of the present invention has disclosed a twin-loop type window glass antenna device for an automobile telephone shown in FIG.
No. 4 publication proposes this. The conventional window glass antenna device 101 for a car telephone shown in FIG. 5 has two half-loop conductors 103a,
103b, reactance element conductors 104a and 104b added to the respective half-loop conductors 103a and 103b, and a ground conductor 105. Each reactance element conductor 1
04a and 104b are the half loop conductors 103a and 103, respectively.
The end portion of b and the ground conductor 105 are connected to each other in an L shape.

Then, each half-loop conductor 103a, 103
The connection point of b is the feeding point 106, the core wire 107a of the feeding cable 107 is connected to the feeding point 106, the outer conductor 107b of the feeding cable 107 is connected to the ground conductor 105, and the antenna 101 is unbalanced. Power is being supplied.

[0004]

Since the ground pattern of the conventional car telephone antenna is not connected to the car body ground, noise generated from other electronic devices such as FM receivers and TV receivers mounted on the car. Are easily affected by and may interfere with the call.

Therefore, it is conceivable to reduce the mixing of noise by connecting the ground pattern of the car telephone antenna to the vehicle body ground. However, since the existing ground pattern is not provided with connecting terminals and the like, the vehicle body It may be difficult to connect a connection line for grounding, and the antenna characteristics may change due to the grounding of the vehicle body directly from the grounding pattern, whereby desired performance may not be obtained.

The present invention has been made to solve such a problem, and provides a window glass antenna device for an automobile, which is designed to reduce the noise mixture from other electronic devices without significantly affecting the antenna characteristics. The purpose is to provide.

[0007]

In order to solve the above-mentioned problems, a window glass antenna device according to the present invention is a power supply cable for connecting an automobile telephone antenna arranged on a window glass of an automobile and an automobile telephone. In part, the ground side conductor of this power supply cable is electrically connected to the vehicle body ground.

[0008]

Operation: By grounding the vehicle body in the middle of the power feeding cable, it is possible to reduce the noise mixed in without significantly affecting the antenna characteristics.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram of a window glass antenna device for an automobile telephone according to the present invention. This car phone window glass antenna device 1 is a midway portion of a coaxial power supply cable 4 for connecting a car phone antenna 3 arranged on a car window glass 2 to a car phone (not shown).
The power supply cable 4 is stripped off, and the grounding metal 5 is used to press the ground-side conductor (outer conductor) 4a of the power supply cable 4 into pressure contact with, for example, the window frame portion 6 made of a conductive material to make a vehicle body ground connection. Is. Reference numeral 7 is a screw for fixing the ground fitting 5 to the window frame portion 6.

The power supply cable 4 is model number 2.5D-2V
The coaxial cable is used to make the vehicle body ground connection at a point of about 200 mm (cable length) from the power feeding point (the connection point between the power feeding cable 4 and the car phone antenna 3). Further, the car phone antenna 3 is arranged near the lower edge of the glass on the left side of the window glass 2 by about 500 mm from the center in the left-right direction.

FIG. 2 is a detailed pattern diagram of the car telephone antenna according to the present invention. The car phone antenna 3 includes a radiation pattern 31 and a ground pattern 32. The radiation pattern 31 includes a radiation pattern body 31a extending vertically, an extension portion 31b extending leftward from a lower end portion of the radiation pattern body 31a, and a first feeding portion 31c formed at a tip of the extension portion 31b.

The ground pattern 32 includes a ground pattern main body 32a located to the right of the radiation pattern 31, a surrounding portion 32b expanded so as to surround the extending portion 31b of the radiation pattern 31 and the first feeding portion 31c, and a surrounding portion. And a spell top element 32c extending from the middle of the lower part 32b of the lower part 32b to the right and widening the left end part of the surrounding part 32b.
The power feeding unit 32d is used.

The core wire 4b of the power feeding cable 4 is connected to the first power feeding portion 31c, and the ground side conductor (outer conductor) 4a of the power feeding cable 4 is connected to the second power feeding portion 32d. The radiation pattern body 31a and the ground pattern body 3
Although 2a has a hollow pattern, the hollow pattern may be omitted.

The car telephone antenna 3 shown in FIG.
The impedance of the power feeding cable 4 and the impedance of the antenna are sufficiently matched so that the antenna characteristics do not change significantly even if the power feeding cable 4 is connected to the vehicle body ground midway.

FIG. 3 is a graph showing the frequency characteristics of the average gain of the car telephone antenna shown in FIG. The solid line is the characteristic when the power feeding cable 4 is connected to the vehicle body ground, and the dotted line is the characteristic when the vehicle body ground is not connected. The alternate long and short dash line is the characteristic of the standard pole antenna. It can be seen that even if the vehicle body is grounded via the power feeding cable 4, there is almost no difference in the frequency characteristics of the average sensitivity. Further, the average sensitivity of the car phone antenna 3 shown in FIG. 2 is within 2 dB as compared with the standard pole antenna, and it has a good sensitivity-frequency characteristic as a window glass antenna. Recognize.

FIG. 4 is a graph showing the frequency characteristic of the voltage standing wave ratio of the car telephone antenna shown in FIG. FIG. 4A shows the characteristics when the power feeding cable 4 is connected to the vehicle body ground, and FIG. 4B shows the characteristics when the vehicle body is not grounded. Even if the vehicle body is connected to earth, the voltage standing wave ratio hardly changes. This indicates that the car phone antenna 3 realizes stable impedance matching regardless of whether or not the vehicle body is connected to the ground.

As described above, the window glass antenna device 1 for a car telephone according to the present invention is provided with the coaxial feed cable 4 for connecting the car telephone antenna 3 arranged on the window glass 2 to the car telephone. In the portion, the coating of the power supply cable 4 is stripped off and the ground side conductor (outer conductor) 4a is connected to the vehicle body ground using the grounding metal fitting 5 or the like. Therefore, the impedance of the ground pattern 32 of the car telephone antenna 3 to the vehicle body ground Is reduced, and noise contamination from other electronic devices is reduced.

The shape of the pattern of the antenna for a car telephone is arbitrary as long as the impedance matching can be sufficiently achieved, and the antenna is not limited to the modified monopole type shown in FIG. 2, but for example, the loop type shown in FIG. May be

[0019]

As described above, the window glass antenna device for a car telephone according to the present invention has a structure in which the vehicle body is grounded in the middle of the power feeding cable, so that the antenna characteristics are not significantly affected and the noise is suppressed. Mixing can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a window glass antenna device for an automobile telephone according to the present invention.

FIG. 2 is a detailed pattern diagram of a car phone antenna according to the present invention.

FIG. 3 is a graph showing the frequency characteristics of the average gain of the car phone antenna shown in FIG.

FIG. 4 is a graph showing the frequency characteristic of the voltage standing wave ratio of the car phone antenna shown in FIG.

FIG. 5 is a schematic structural diagram of a conventional window glass antenna device for an automobile telephone.

[Explanation of symbols]

 1 Window glass antenna device for car phone 2 Window glass 3 Antenna for car phone 4 Power cable 5 Grounding metal

Claims (1)

[Claims] 1. A grounding side conductor of the power feeding cable is electrically connected to a vehicle body ground at an intermediate portion of a power feeding cable for connecting a car telephone antenna arranged on a window glass of a car and a car telephone. A window glass antenna device for a car telephone, which is characterized by: