JPH0653722A - High frequency glass antenna for automobile - Google Patents

Abstract

PURPOSE:To receive a GPS signal in an excellent way by providing an antenna conductor on a window glass of an automobile, using two points at both sides of the antenna conductor in the vicinity of its opening as feeding points and sending the signal to a receiver via a preamplifier circuit. CONSTITUTION:One side of a quadrangular is missing in an antenna conductor 2, and the missing one side is an opening part. The conductor 2 is formed through baking with Ag paste, and leg parts 5a, 5b and a feeding point connecting to an end of the opening of the conductor 2 are connected by soldering. It is preferred that the shape of the conductor 2 being a line or stripe conductor pattern is almost circular, elliptic, triangle or polygonal. The length of the conductor 2 is preferred to be within a range of 80-120% with respect to a reception wavelength. A preamplifier circuit is built in an insulation box 3, one end of the leg part 5a is connected to an input section of the preamplifier circuit and one end of the leg part 5b is connected to ground. A relay terminal 4 is a coaxial terminal, has a characteristic impedance of 50ohms and is used to apply a GPS signal to a receiver.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency glass antenna for automobiles.

[0002]

2. Description of the Related Art Conventional high frequency antennas for automobiles, especially G
As for the antenna for PS satellites, a GPS antenna with a preamplification circuit is arranged in the vicinity of a microstrip antenna in which conductor layers are formed on the front and back surfaces of a three-dimensional dielectric plate to serve as an antenna conductor and a ground conductor. It is already on the market.

This conventional GPS antenna is used by fixing it on the roof and trunk of an automobile by a magnet attached to a case or a mounting bracket, or by fixing it in a vehicle interior near the opening of the automobile by a method such as screwing. It had been. However, the conventional GPS antenna has a large shape, and when it is installed on the roof and the trunk, there is a problem in that it is aesthetically unpleasant, and there is a high risk of theft. In addition, since it is installed outside the vehicle, there is a problem that it will change over time.

Further, even when installed in the vehicle interior near the window of the vehicle, a large space is required for installation, and when the window of the vehicle through which radio waves enter the vehicle interior is seen from the installed position, the field of view is There is a problem that the reception range becomes narrow because the angle becomes narrow.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is to eliminate the above-mentioned drawbacks of the prior art. That is, since it can be installed in the vehicle compartment, there is less risk of theft, less change over time, and a small antenna that does not impair aesthetics. Is intended to be newly provided.

[0006]

The present invention has been made to solve the above-mentioned problems, and a linear or band-shaped antenna conductor is formed on a glass plate of an automobile window in a substantially circular shape having an opening, A vehicle characterized by being provided in a substantially elliptical shape or a substantially polygonal shape, with two points on both sides in the vicinity of the opening of the antenna conductor as feeding points, and a reception signal at both feeding points is amplified by a preamplifier circuit and sent to a receiver. The present invention provides a high frequency glass antenna. The present invention also provides the high frequency glass antenna for an automobile, wherein the antenna conductor is provided with a branch line. The present invention also provides the above high-frequency glass antenna for an automobile, characterized in that a reflector wire is provided near the antenna conductor.

[0007]

[Embodiment 1] FIG. 1 is a perspective view showing a first embodiment. 1 in FIG. 1 is a glass plate of an automobile window, 2 is an antenna conductor, and 3 is an insulating box containing a preamplification circuit. Reference numeral 4 denotes a relay terminal, and 5a and 5b denote legs made of metal fittings for joining the insulating box 3 to the glass plate 1. Also, both legs 5a, 5b
There are two feeding points of the antenna conductor 2 immediately below. 10
Is a branch line having a function for adjusting impedance, etc., provided as necessary, but it was not provided in Example 1.

In the first embodiment, the antenna conductor 2 is 1575.
It was designed for the purpose of receiving a 42 MHz GPS signal. The antenna conductor 2 having a rectangular shape of 61 mm × 61 mm is adopted as the antenna (the feeding point portion is not included). The antenna conductor 2 does not have one side of the quadrangle, and the portion corresponding to this one side is the opening. The antenna conductor 2 was formed by printing using Ag paste with a film thickness of about 50 μm and a line width of 1 mm, and then firing. Legs 5a and 5
b was connected to the feeding point connected to the end of the opening of the antenna conductor 2 by soldering.

With respect to the shape of the antenna conductor 2, it is preferable that the linear or strip-shaped conductor pattern is substantially circular, elliptical, triangular, or polygonal. When the shape is a substantially triangular shape or a substantially polygonal shape, the apex may be rounded. Further, the present invention is suitable for reception in the frequency band of 300 MHz to 3 GHz, but the length of the antenna conductor 2 is appropriate in the range of 45 to 150% of one wavelength of the received radio wave in terms of reception characteristics, and 80 The range of up to 120% is more desirable. The line width of the antenna conductor 2 is suitably 0.2 to 5 mm. If it is 0.2 mm or less, it is difficult to form it on the glass plate 1, and if it is 5 mm or more, it impairs the visibility.

The insulating box 3 is made of epoxy resin of 50 × 16 × 4 mm and has a built-in preamplifier circuit. The legs 5a and 5b are tin-plated brass with a plate thickness of 0.5 mm, one end of the leg 5a is connected to the input part of the preamplifier circuit, and one end of the leg 5b is grounded.

In the relay terminal 4, the inner conductor is covered with resin,
Furthermore, it is a so-called coaxial type terminal in which the resin is covered with an outer conductor, and is a cylindrical shape with a diameter of 2.5 mm and a length of 4 mm.
It has a characteristic impedance of 0Ω.

FIG. 2 is a cross section of the output portion of the insulating box 3. In FIG. 2, the outer conductor and the inner conductor at the end of the relay terminal 4 are soldered to the circuit board 6 provided with the preamplifier circuit, and the circuit board 6 and the relay terminal 4 are partially built in the insulating box 3. Has been done. By using the relay terminal 4, the insulation box 3
It is possible to take out the output of the preamplifier circuit while environmentally blocking the inside and outside of the.

The received radio wave excited in the antenna conductor 2 is fed by the leg portion 5a, sent to the preamplifier circuit built in the insulating box 3, and amplified. The amplified output is passed through the relay terminal 4 and the coaxial cable connected to the relay terminal 4,
Input to the receiver installed separately. The power supply for driving the preamplifier circuit is supplied from the receiver to the circuit via the coaxial cable and the relay terminal 4. That is, the output of the preamplifier circuit and the power supply are superposed. However, the power supply method is not limited to this, and another method may be used.

The antenna conductor 2 is preferably Ag (silver), but can be Ag-Pd (palladium) or another metal film. The antenna conductor 2 has a so-called thick film thickness of 1
The range of 0 μm to 200 μm is desirable. Legs 5a, 5b
Not limited to brass, copper or other metal may be used, and the antenna conductor 2 may be joined to the feeding point by soldering, a conductive adhesive, or the like. The characteristic impedance of the relay terminal 4 is not limited to 50Ω, but it is desirable to match the output impedance of the coaxial cable and the amplifier to be used, and a feedthrough capacitor can also be used.

FIG. 3 is a sectional view of the rear portion of the automobile, showing the relationship between the antenna mounting position and the receiving range. In FIG. 3, 7 is a glass antenna for a vehicle high frequency according to the first embodiment, and the receivable range (angle) in the elevation direction is α (d
eg). Reference numeral 8 is a GPS antenna using a conventional microstrip antenna, which is installed on the sun deck at the rear of the seat. It can be seen that the receivable range (angle) in the case of the microstrip antenna 8 is β (deg), and α> β.

FIG. 4 shows the directional data and the receivable range α of the first embodiment, and FIG. 5 shows the directional data and the receivable range β of the conventional product. The data shows the gain of the dipole antenna ratio, which shows that the high frequency glass antenna of Example 1 has a wide receivable range and an excellent gain within the receivable range.

[Embodiment 2] A branch line 1 is attached to an antenna conductor 2.
A high-frequency glass antenna having specifications such as the same shape, dimensions, and mounting method as in Example 1 except that 0 was provided was prepared.
The branch line 10 is provided because by providing the branch line 10, the impedance of the high frequency glass antenna can be made variable, and impedance matching with the input impedance of the preamplifier or the like connected to the next stage can be facilitated. ,
This is because the branch line 10 functions as a reflector or a director and can improve the reception sensitivity in a specific direction.

The impedance of the second embodiment has a resistance of 35.
2Ω, reactance component-40.1Ω, that is, (35.
2-j40.1Ω) and the impedance of Example 1 (when the branch line is not provided) is (19.3-j14.7Ω).
It can be seen that the impedance changes due to the branch line 10.

6 to 9 show the antenna conductor 2 and the branch line 10.
It is a modification example of. 6 is different from the second embodiment in that the branch line 10
Is an example of extending the left and right. FIG. 7 shows an example in which the branch line 10 has an inverted T shape. FIG. 8 shows an example in which the branch line 10 has a loop shape. FIG. 9 shows the branch line 1 on the outside of the antenna conductor 2.
The case where 0 is provided is shown. Note that the number of branch lines 10 is not limited to one and may be multiple.

Whether the branch line 10 is provided inside or outside the antenna conductor 2, it can contribute to the improvement of the antenna gain and the like. However, when it is necessary to reduce the size, it is preferable to provide it inside the antenna conductor 2.

The branch line 10 is not limited to a straight line, and the branch line 10 itself may have a loop shape, a circular shape, an elliptical shape, or a combined shape of a straight line or a curved line and a loop shape as shown in FIG. When a part or all of the branch line 10 has a loop shape or the like, the branch line 10 may have a discontinuous portion or an opening portion at a part thereof.

Although the branch line 10 is connected to the antenna conductor 2 in a direct current manner, the branch line 10 and the antenna conductor 2 may be partially disconnected and provided separately. In this case, the distance between the branch line 10 and the antenna conductor 2 is 0.1 mm to 2
In the case of 0 mm, since the branch line 10 and the antenna conductor 2 are capacitively coupled, the impedance of the antenna conductor 2 can be adjusted by the branch line 10, and the branch line 10 also functions as a reflector or a director. .

The distance between the branch line 10 and the antenna conductor 2 is 2
If it exceeds 0 mm, it becomes difficult to capacitively couple, and the branch line 1
0 mainly functions only as a reflector. The branch line 10 thus separated from the antenna conductor 2 is referred to as a reflector line.

In the second embodiment shown in FIG. 1, the branch line 10
Has a length of 30 mm (1/4 wavelength of received radio wave)
This is because it is intended to increase the influence on the impedance as x (shortening rate of glass antenna (0.6)). The length of the branch line is usually (1/4 wavelength of received radio wave) x
(0.6) × ((1/3) to 2) is suitable. In the second embodiment, the line width of the branch line 10 is set to 1 mm, which is the same as that of the antenna conductor 4, but a range of 0.2 mm to 5 mm is preferable. Example 2 (branch line shown in FIG. 1 (length = 30
The reception gain for the high frequency glass antenna (including mm) is shown in FIG. 4 together with the result of the first embodiment.

[0025]

According to the present invention, since the antenna conductor provided on the glass plate of the window of the automobile is used as the antenna, the antenna device can be miniaturized, and the frequency range of 300 MHz.
There is an effect that a wide frequency range of about 3 GHz can be received with good reception sensitivity, and a wider reception angle range can be secured. Further, since it can be installed in the passenger compartment, the effect of not impairing the design of the automobile and reducing the risk of theft can be recognized. Further, when the branch line is provided on the antenna conductor, a high receiving sensitivity of several dB or more can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment.

FIG. 2 is a sectional view of an output part of the insulation box 3.

FIG. 3 is a cross-sectional view of the rear part of the vehicle showing the receivable range

FIG. 4 is a characteristic diagram of the reception gain of the embodiment.

FIG. 5 is a characteristic diagram of reception gain of a conventional example.

FIG. 6 is a front view showing an embodiment of a modified antenna conductor and branch line.

FIG. 7 is a front view showing an embodiment of a modified antenna conductor and branch line.

FIG. 8 is a front view showing an embodiment of a modified antenna conductor and branch line.

FIG. 9 is a front view showing an embodiment of a modified antenna conductor and branch line.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1: Glass plate 2: Antenna conductor 3: Insulation box 4: Relay terminals 5a, 5b: Leg part 6: Circuit board 7: High frequency glass antenna for automobile of the example 8: Conventional GPS antenna 10: Branch line

Claims (3)

[Claims] 1. A linear or band-shaped antenna conductor is provided on a glass plate of an automobile window in a substantially circular shape, a substantially elliptical shape, or a substantially polygonal shape having an opening, and two points on both sides near the opening of the antenna conductor. A high-frequency glass antenna for an automobile, characterized in that the reception signal at both feeding points is amplified by a preamplifier circuit and sent to a receiver. 2. The high frequency glass antenna for automobiles according to claim 1, wherein the antenna conductor is provided with a branch line. 3. A high frequency glass antenna for an automobile according to claim 1, wherein a reflector wire is provided near the antenna conductor.