JPH01277005A - Glass antenna for vehicle - Google Patents

Abstract

PURPOSE:To receive the whole area of TV broadcast waves and FM broadcast waves by composing the title antenna of a main antenna and an impedance adjusting antenna. CONSTITUTION:A U-shaped main antenna 2 is extended along the edges of a window glass 1 to the central part of its upper side and further, it is extended vertically from the central part to the central part of its lower side with the lower end part of one side of the window glass 1 for vehicle as a feeding point 4. An impedance adjusting antenna 3 is inserted into a part arranged on one side of the window glass 1. When receiving the TV broadcast or FM broadcast waves, the U-shaped antenna operates as main antenna over the whole area of their frequency. The adjusting antenna 3 approximates the impedance of the antenna 2 to the impedance of a feeder line, the drop of receiving gain due to partial mismatching when not matched is decreased and broad-band reception is attained.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a glass antenna for vehicles such as automobiles.

[Conventional technology]

Conventionally, as a glass antenna for vehicles, a filament antenna was installed in the space above the anti-fogging heating filament of the rear window glass, either separate from the heating filament for exclusive use, or connected to it for dual use as anti-fog. It has been known.

Further, a glass antenna is known in which a transparent conductive pattern or a wire antenna is provided on the front window glass.

[Problem that the invention seeks to solve]

However, the former dedicated antenna cannot obtain sufficient reception gain when receiving TV broadcast waves and FM broadcast waves due to its narrow antenna footprint, and the anti-fog antenna also generates noise due to the flow of thermal current during anti-fog. Contamination was unavoidable.

In addition, the latter antenna installed on the front window glass has a relatively high reception gain and has been attracting attention in recent years, but the TV broadcast band is VH.
F band is 90Ml1z~222MHz, UHF band is 47
Since the frequency band is extremely wide from 0 MHz to 770 MHz, it has been difficult to obtain a glass antenna with high gain over the entire range.

The present invention has been made in view of these points, and an object of the present invention is to provide a wideband receiving antenna suitable for receiving the entire range of TV broadcast waves and FM broadcast waves.

[Means for solving problems]

The glass antenna of the present invention has a substantially U-shaped shape that uses the lower end of one side of a vehicle window glass as a feeding point, extends along the periphery of the window glass to the center of the upper side, and further extends vertically from the center to the center of the lower side. It is characterized by consisting of a main antenna and an impedance adjustment antenna that is connected to or inserted into a portion of the main antenna that is disposed on one side of the window glass.

[Operation] When receiving TV broadcast waves or radio broadcast waves, the substantially U-shaped antenna acts as the main antenna over the entire frequency range.

The impedance adjustment antenna adjusts the impedance of the antenna to the impedance of the feeder line (coaxial cable) (
By approximating the resistance component Rf=75Ω), it is possible to reduce the drop in reception gain due to partial mismatched singing when unmatched and to enable wideband reception. The mismatch M due to mismatching between the impedance Za of the antenna and the impedance Zf of the feeder line is M=1.
/(1−l r l ”)(r= (Z, −Zf )/
(2,+21)). Z,=R,=75
Ω, Za = Ra + jXa, the antenna resistance x1 should be close to OΩ, but ±150Ω
Although the mismatched chant M increases to a certain extent, it is within an acceptable range. On the other hand, the resistance R.

Of course, it is better for Ω to be close to 75Ω, but if it is smaller than 75Ω, the mismatch that increases due to the difference (75-R,)Ω is extremely large, and if it is larger than 75Ω, the difference (R, - 75) The mismatch M that increases with Ω is relatively small. Therefore, in the impedance adjustment antenna of the present invention, in particular, when approximating the resistance R1 to 75Ω, the mismatch M is reduced by approximating it to the + side, and as a result, broadband reception is possible.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings.

1 to 4 are front views of the glass antenna of the present invention mounted on a front windshield for an automobile.

Example 1 A laminated glass for the front window glass was made by bonding two sheets of glass with an interlayer film such as polyvinyl butyral.
As shown in FIG. 1, a substantially U-shaped main antenna 2 and an impedance adjustment antenna 3 are printed and fired together with a feed point 4 on a car-inside plate glass l using conductive paste.

In the glass antenna with such a configuration, the dimensions of each part are AI・1.200mm, Az=1.480mm, B=
740 臘獽, H1・580 鳳1, H2・6
60 *Seal, M・545 double seal m1L=220
mm, a=80mm, b=50mm, c=60m
The reception gain when receiving FM radio broadcast waves and TV broadcast waves using m is 76MHz, where the reception gain of a standard Guibor antenna is OdB, and the gain difference (hereinafter abbreviated as dipole ratio) is 76MHz. Average domestic FM radio broadcast waves at ~90MHz, 88MHz~10
Average of foreign FM radio broadcast waves at 8 MHz, average of 7 channels of VHF band of TV broadcast waves of 1 channel and 12 channels, UHF band of TV broadcast waves 470 MHz to 7
-15, 1 dB, - respectively at 70 MHz average
The receiving gains are 15.7 dB, -16.2 dB, and -17.4 dB, and the receiving gains of conventional windshield antennas that are in practical use are all around -18 dB, so it can be seen that they are good antennas.

In addition, the TV of the antenna of Example 1 with only the U-shaped main antenna and with the addition of an impedance adjustment antenna.
When we measured the impedance and reception gain G (dipole ratio) for each channel of the broadcast wave and νHF band, we found that the first
As shown in the table, it is clear from the results that the U-shaped antenna alone can provide good reception gain and acts as the main antenna. Xa ±100
It can be seen that in addition to keeping it within Ω, it also has the effect of shifting the resistance component Ra to the + side, further improving the reception gain.

As shown in Table 1 and Figure 2, the impedance adjustment antenna 3
It has the same configuration and dimensions as Example 1 except that it is arranged parallel to the horizontal part of the main antenna 2 with L = 320 mm, and the reception gain is lower than that of Example 1 for TV broadcast waves,
Almost the same effect was obtained with FM broadcast waves.

As shown in Figure 3, the configuration is the same as in Example 1 except that the T-shaped impedance adjustment antenna 3 is arranged with L = 300 mm, and the reception gain is compared with Example 1. Almost the same results were obtained for both TV broadcast waves and FM broadcast waves.

As shown in Figure 4, an impedance adjustment antenna with U-shaped elements arranged in a zigzag pattern is inserted into the main antenna 2, and its reception gain is the same as that of the embodiment for both TV broadcast waves and FM broadcast waves. A value almost close to 1 was obtained.

Although the preferred embodiments have been described above, the glass antenna of the present invention is not limited to these and can be applied in various ways.

The vertical length H of the main antenna does not necessarily have to be the resonance length, but may be 500 mm or more depending on the size of the window glass.
The length may be appropriately selected within a range of up to about 1000 mm. In addition, if the power supply point is located at the bottom edge of one side of the window glass,
Not only is wiring easy and aesthetically pleasing, but the U-shape of the main antenna provides an improvement of about 1 dB compared to an inverted U-shape.

As mentioned above, the impedance adjustment antenna mainly has the function of adjusting resistance rather than reactance, so it has an L-shape (Example 1), a straight line shape (Example 2), a T-shape (Example 3), and a zigzag shape. In addition to the shape (Example 4), various shapes such as a U-shape can be used. Further, the location where the impedance adjustment antenna is connected or inserted is preferably near the feeding point of the main antenna, but may be appropriately selected from a portion disposed along the side of the window glass 1 from the feeding point of the main antenna.

The antenna is not limited to a printed wire made by printing and firing a conductive paste, but may also be formed by embedding a thin metal wire such as a copper wire in an interlayer film that contacts two sheets of glass. Further, when laminated glass is used for the rear window glass, anti-fogging heating stripes may be provided on the inside plate glass, and thin metal wires may be embedded in the interlayer film.

Although the glass antenna of the present invention may of course be used alone, it is more preferable to use it in combination with other glass antennas, ball antennas, etc. for diversity reception.

〔Effect of the invention〕

The vehicle glass antenna of the present invention can be used not only for domestic and foreign FM radio broadcast waves, but also for TV broadcast waves in the VHF band and UH band.
This antenna has improved reception gain in the F band, and is suitable as a wideband reception antenna covering a very wide range of frequencies.

[Brief explanation of the drawing]

1 to 4 are front views showing an embodiment in which the glass antenna of the present invention is attached to a front window glass for an automobile. 100. Car interior plate glass 210. Main antenna 301.
Impedance adjustment antenna 401. Power supply point Figure 1 Figure 2

Claims (1)

[Claims] In a glass antenna for a vehicle in which an antenna element is provided on a window glass, the antenna element uses the lower end of one side of the window glass as a feeding point, extends along the periphery of the window glass to the center of the upper side, and then extends from the center to the center of the lower side. A glass antenna for a vehicle, comprising a substantially U-shaped main antenna that extends vertically up to 100 cm, and an impedance adjustment antenna that is connected to or inserted into a portion of the main antenna that is disposed on one side of a window glass. .