JPH06244616A - Glass antenna for automobile - Google Patents

Abstract

PURPOSE:To form a compact glass antenna on a glass plate even when the band of a broadcasting frequency to be covered is wide by connecting respective antenna conductors by using a reactance circuit. CONSTITUTION:This antenna is composed of a glass plate 1, heater wire 2, antenna conductors 3a-3f, reactance circuit 4, power feeding point 5 and TV receiver 6. The heater wire 2, antenna wire 3a and power feeding point 5 are the conductive films of Ag or the like formed on the glass plate 1 by any method such as screen printing. Then, the reactance circuit 4 is inserted to the intermediate part of the respective antenna conductors 3a-3f and connects the respective antenna conductors 3a-3f. With the cut-off characteristics of this reactance circuit 4, radio wave signals received by the respective antenna conductors 3a-3f to vary the antenna effective lengths for each frequency band are sent through the power feeding point 5 to the TV receiver 6. Namely, the reactance circuit 4 is inserted to the inter-mediate part of the antenna wire 3 so that the antenna effective length can be varied for each frequency band.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass antenna for automobiles, which is suitable for receiving television (TV) broadcasting.

[0002]

2. Description of the Related Art Conventionally, as a TV glass antenna for an automobile, it is known that a plurality of antenna conductors having different lengths are provided on a glass plate of the automobile to perform diversity reception. However, since the car antenna is mobile reception, omnidirectionality is required. Further, since the TV broadcast has a wide carrier frequency, the conventional glass antenna is a diversity antenna, which complicates the TV receiver. It was In addition, it is difficult to secure a space for the glass plate of the window in which the antenna conductor is provided, which requires time for development and cannot obtain sufficient reception sensitivity.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide the above-mentioned drawbacks of the prior art, that is, the TV receiver becomes complicated, the antenna development takes time, and sufficient sensitivity is not obtained. The idea is to eliminate things that cannot be obtained.

[0004]

The present invention has been made to solve the above-mentioned problems, and a plurality of antenna conductors are provided on a glass plate of an automobile window, and each antenna conductor is formed by a reactance circuit. It is a glass antenna for an automobile characterized by being connected.

Further, according to the present invention, the reactance circuit is provided in the convex portion of the terminal fitting having the leg portions on both sides, and the central portion sandwiched by the leg portions is bent upward to provide the convex portion, and The above-mentioned glass antenna for an automobile, in which a metal fitting is provided on a glass plate of an automobile window.

[0006]

In the present invention, the frequencies are f ₀ , f ₁ , f ₂ ,
Since the impedances of the reactance circuits 4a, 4b, 4c, and 4d are close to zero at the frequency f ₀ when the frequency is gradually increased to f ₃ , the antenna filaments 3a, 3b, 3c,
3d, 3e, and 3f, and the received radio signal is fed to the feeding point 5
You can take it out with.

Similarly, at the frequency f ₁ , the reactance circuit 4c excludes the antenna conductors 3e and 3f,
3a, 3b, 3c, 3d are effective lengths, and similarly,
The antenna conductor 3a is excluded by the reactance circuit 4a and the antenna conductor 3f is excluded by the reactance circuit 4d at the frequency f ₂ , and the effective lengths of 3b, 3c, 3d, and 3e are similarly obtained. At the frequency f ₃ , the reactance circuits 4b and 4c The antenna wire has an effective length of 3c and 3d.

As described above, the effective length of the antenna wire can be changed for each frequency band. Further, as in the reactance circuit 4a, by lowering the Q value, it is possible to gradually change the effective length around the antiresonance frequency, that is, widen the frequency band. Further, as in the reactance circuit 4c, by having a plurality of anti-resonance frequencies, it is possible to configure an arbitrary antenna filament for each frequency. As the reactance circuit, various circuits can be considered as shown in FIG.

According to FIG. 1, the antenna conductors 3c and 3d are branched from the feeding point 5 to form an arbitrary antenna for each frequency. However, except when a plurality of antenna conductors are extended from the feeding point 5. Also, it is possible to provide a plurality of antenna conductors from one antenna conductor through a reactance circuit and select the optimum effective length of the antenna wire.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a glass plate, 2 is a heater filament, and 3
a, 3b, 3c, 3d, 3e, 3f are antenna conductors, 4
Is a reactance circuit, 5 is a feeding point, and 6 is a TV receiver.

The heater wire 2, the antenna wire 3a, and the feeding point 5 are conductive films of Ag or the like formed on the inner surface of the glass plate 1 by a method such as screen printing. The reactance circuit 4 is inserted in the middle of each antenna conductor and connects each antenna conductor.

Due to the cutoff characteristic of the reactance circuit 4,
The radio signal received by each antenna conductor whose antenna effective length is variable for each frequency band is sent to the TV receiver 6 via the feeding point 5. For example, since the reactance circuit 4a is anti-resonant at a certain frequency f ₂ , the antenna conductor 3a is removed in the vicinity of the frequency f ₂ , and similarly, the reactance circuit 4b removes the antenna conductors 3a and 3b. The antenna parts 3e and 3f are removed by 4c, and the antenna conductor 3 is removed by the reactance circuit 4d.
f is excluded. Thus, the reactance circuit 4 is inserted in the middle of the antenna wire 3 so that the antenna effective length is variable for each frequency band.

The reactance circuits 4a, 4b, 4c,
4d is basically the anti-resonance circuit of the coil 14 and the capacitor 15, but like the reactance circuit 4a, the resistance 11
The Q value may be lowered by the above, or the reactance circuit 4c may have two antiresonance frequencies f ₁ and f ₃ . Each reactance circuit is shown in FIG.
It may be a modified one as shown in (f).
As shown in (g) and (h), it may have three anti-resonance points.

It is preferable that the impedance characteristic of the reactance circuit 4 approaches zero when the frequency approaches infinity or infinity. TV broadcasting frequencies in Japan are 90-225 MHz for VHF band and 470 for UHF band.
It is a fairly wide band of ˜770 MHz. Therefore, in general, the VHF band is divided into two, and the VHF-Low band is 90 to 110 MHz at a central frequency of 100 MHz and VHF-H.
170 to 22 with a center frequency of 198 MHz as the high band
A TV receiver member such as an antenna was set as 5 MHz. In the embodiment, the UHF band is further divided into two, and the center frequency is 5
Low band of 470 to 620 MHz at 45 MHz and High of 620 to 770 MHz at center frequency 695 MHz
4 bands including the VHF band Low band and High band
Antennas were set by dividing into bands.

In FIG. 1, the antiresonance frequency of the reactance circuit 4a is set to 545 MHz. Coil 3 is 3
3 nH, capacitor 12 is 3 pF, resistor 13 is 10 k
Ω. The anti-resonance frequency of the reactance circuit 4b is 69
The coil 14 was 27 nH, the capacitor 15 was 2 pF at 5 MHz, and the antiresonance frequencies of the reactance circuit 4c were set to 198 MHz and 695 MHz. Coil 16 is 100 nH, coil 17 is 115 nH, capacitor 1
8 is 6 pF and the condenser 19 is 0.5 pF. The antiresonance frequency of the reactance circuit 4d is 545 MHz, the coil 20 has 33 nH, and the capacitor 21 has 3 pF.
Is.

Further, the vertical portion of the two antenna conductors 3a is 20 cm, the longest horizontal portion is 90 cm, the length of the antenna conductor 3b is 35 cm, and the length of the antenna conductor 3c is 2.
The length of the antenna conductor 3d is 20 cm, the length of the antenna conductor 3e is 9 cm, the length of the longest part of the antenna conductor 3f is 101 cm, and the line width of each antenna conductor 3 is 0.8 cm. It is a thick film.

3 and 4 show that the terminal fittings for accommodating the reactance circuit are attached to the window glass plate of the automobile by soldering. In FIG. 3, 31 is a glass plate of an automobile window, 32 is a resin for molding, and 35, 36.
Is an antenna conductor, 37 and 38 are legs of terminal fittings, 39 is a circuit board made of ceramics or resin on which a reactance circuit is mounted, and 40 is an electronic component. In FIG. 4, 41
Is a glass plate of an automobile window, 45 and 46 are antenna conductors,
49 is a reactance circuit and 47 and 48 are legs of the terminal fittings.

When the reactance circuit is housed in the terminal fitting and attached to the glass plate in this manner, environmental characteristics such as humidity resistance are improved, and the S / N ratio is improved by about 1 to 2 db.

[0019]

According to the present invention, even when the band of the broadcast frequency band which must be covered is wide, it is less necessary to provide an antenna conductor having a different length from the conventional one, and a compact glass antenna is placed on a glass plate of a window. Can be formed,
And it is also aesthetically pleasing. Further, when the reactance circuit is mounted on the terminal fitting and attached to the glass plate of the window, it becomes compact and the S / N ratio is improved by about 1 to 2 db.

[Brief description of drawings]

FIG. 1 is a front view of an embodiment.

FIG. 2 is a circuit diagram of a modified reactance circuit.

[Figure 3] Side view of the terminal fitting

FIG. 4 is a perspective view of another terminal fitting.

[Explanation of symbols]

 1: Glass plate 2: Heater wires 3a, 3b, 3c, 3d, 3e, 3f: Antenna conductors 4a, 4b, 4c, 4d: Reactance circuit

Claims (2)

[Claims] 1. A glass antenna for an automobile, characterized in that a plurality of antenna conductors are provided on a glass plate of a window of an automobile, and each antenna conductor is connected by a reactance circuit. 2. A reactance circuit is provided in a convex portion of a terminal fitting having leg portions on both sides, and a central portion sandwiched by the leg portions is bent upward to provide a convex portion, and the terminal fitting is provided in an automobile. The glass antenna for an automobile according to claim 1, which is provided on the glass plate of the window.