JPH01292902A - Glass antenna for vehicle - Google Patents

Abstract

PURPOSE:To attain wide band reception by composing a glass antenna for vehicle of main antenna, which is vertically extended up to a lower side central part with defining the upper side central part of a window glass as the feeding point, and an antenna for impedance adjustment, which is connected to the main antenna near a feeding point. CONSTITUTION:The two glasses are adhered by an intermediate film such as polyvinyl butyral and obtained as a laminated glass for front part window glass. Then, a main antenna 2 and an antenna 3 for impedance adjustment are printed to a side board glass 1 in vehicle by a conductive paste together with a feeding point 4 baked and formed. Namely, an antenna element is composed of the main antenna 2, which is vertically extended up to the lower side with defining the upper side central part of the window glass as the feeding point 4, and the antenna 3 for impedance adjustment, which is connected to the main antenna 2 near the feeding point 4. Thus, the glass antenna goes to be suitable as a wide band reception antenna over the all frequency areas of an extremely wide range.

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 film 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 because the antenna footprint is small, and the anti-fog antenna has anti-fog heating strips that flow and generate noise. 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 90MHz to 222MHz, UHF band is 470MHz
Since the frequency band is extremely wide ranging from 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 vehicle glass antenna of the present invention is a window glass.

It is characterized by consisting of a main antenna that extends vertically to the center of the lower side with the feed point at the center of the upper side, and an impedance adjustment antenna connected to the main antenna near the feed point.

[Effect]

When receiving TV broadcast waves or FM radio broadcast waves,
Over its entire frequency range, the vertical section acts as the main antenna.

The impedance adjustment antenna adjusts the impedance of the antenna to the impedance of the feeder line (coaxial cable) (
By approximating the resistance (Rf = 75Ω), it is possible to reduce the drop in reception gain due to partial mismatching when unmatched and to enable broadband reception. M for mismatching due to mismatching between antenna impedance Za and feeder line impedance Zf is M=1.
/(1-l r l 2) (I”= (Z, -Zf
)/(Z, +zt)). Zt=R
If r = 75Ω and Za = Rm + jx, the antenna resistance actance X1. should be closer to OΩ, but
Although the mismatch M increases up to approximately ±150Ω, this is within an acceptable range. On the other hand, it is of course better for the resistance bone R1 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 increased by Ω is relatively small. Therefore, in the impedance adjustment antenna of the present invention, in particular, when approximating the resistance bone R1 to 75Ω, the mismatch M is made smaller by approximating it to the + side, and as a result, wideband 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.

This is a laminated glass for the front window glass made by bonding two glass plates made of charcoal clay with an interlayer film such as polyvinyl butyral.
As shown in Fig. 1, a main antenna 2 and an impedance adjustment antenna 3 are attached to the inside plate glass 1 using conductive paste.
is formed by printing and firing together with the power feeding point 4.

In a glass antenna with such a configuration, the dimensions of each part are A, 1, 2001, Az=1.48On+5B
=740u+XH=580u, L, =200mm,
Lz=100mm.

By setting a=10mm, FM radio broadcast wave, T
The reception gain when receiving V broadcast waves is expressed as the gain difference (hereinafter referred to as dipole ratio), assuming that the reception gain of a standard dipole antenna is OdB, and is 76MH2~9.
Average domestic FM radio broadcast wave at 0MHz, 88M
Average foreign FM radio broadcast waves from Hz to 108 MHz, VH of TV broadcast waves from channels 1 to 12
Average of F band 7 channels, TV broadcast wave UHF band 470
-15, respectively, on average from MHz to 770 FIHz
8dB, -15,2dB, -16,1dB, -17,3
dB! : Since the receiving gain of conventional windshield antennas that are in practical use are all around -18 dB, it can be seen that they are good antennas.

In addition, when we measured the impedance and reception gain G (dipole ratio) for each channel of the TV broadcast wave and VHF band for the case of only the main antenna in the vertical section and the antenna of Example 1 with the addition of an impedance adjustment antenna, Table 1 shows the results. As shown in the results, it is clear that the antenna in the vertical section can obtain good reception gain by itself and acts as the main antenna, and the impedance adjustment antenna adjusts the reactance Xa by ± It can be seen that the resistance is within 110Ω, and in particular, the resistance bone Ra is shifted almost to the + side, further improving the reception gain.

As shown in Table 1 and Figure 2, the impedance adjustment antenna 3
・The configuration and dimensions are the same as in Example 1 except that only the horizontal part of L2 250IllIll is connected to both the left and right sides of the main antenna, and the reception gain is the same for both TV broadcast waves and FM broadcast waves. Good results were obtained.

Embodiment 3 As shown in FIG. 3, impedance adjustment antenna 3
It has the same configuration and dimensions as Example 1, except that it is connected to one side of the main antenna 2 as two horizontal parts of L+□ 550 mm and Lz=450 mm, and the receiving gain is also T.
Almost the same results were obtained for both V broadcast waves and FM broadcast waves.

As shown in Figure 4, the impedance adjustment antenna 3
The configuration and dimensions are the same as in Example 1, except that the main antenna 2 is arranged vertically with a distance of 10 mm and a length of 500 mm, and the reception gain is almost the same for both TV broadcast waves and FM broadcast waves. was gotten.

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 length H of the main antenna does not necessarily have to be the resonance length (depending on the size of the window glass, it can be 500 mm or more, or 1000 mm or more).
It may be selected as appropriate within a range of about +am. Furthermore, by providing the feeding point at the upper end, the receiving gain is improved by about 2 dB compared to the conventional arrangement where the feeding point is provided at the lower end.

As described above, the impedance adjustment antenna mainly has the function of adjusting the resistance component rather than the reactance component, and therefore, in addition to the antenna of the embodiment, various shapes such as a zigzag shape can be used.

In addition, when one end is bent as in Example 1, the length is Lt-200mm±100mm, Lx, 100m
m ±50mm or Lt-550mm ±100m
a+ SLx, 520ma+ ±20mm, Example 1
, if not bent, L+=400mm±1
00mn+, in the case of Example 2, both L1%Lt and 25
0mm±100mm, in the case of Example 3, Lt =
550mm±100mm 5Lz-450mm±100
mm, in the case of Example 4, L = 500 mm ± 100
Similar results were obtained by appropriately selecting the diameter within the range of mm.

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 steel wire in an interlayer film that adheres 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 that covers 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 mounted on a front window glass for an automobile. 1. Vehicle interior plate glass 2. Main antenna 3. Impedance adjustment antenna 4. Feeding point Patent applicant Central Glass Co., Ltd. Figure 1 Figure 2

Claims (1)

[Claims] In a vehicle glass antenna with an antenna element installed on the window glass, the antenna element consists of a main antenna that uses the feeding point at the center of the top side of the window glass and extends vertically to the center of the bottom side, and an impedance adjustment antenna that is connected to the main antenna near the feeding point. A glass antenna for a vehicle, comprising an antenna for use in vehicles.