JPS59198006A - On-vehicle glass antenna - Google Patents

Abstract

PURPOSE:To improve the average gain and directivity characteristic by providing an antenna for adjusting phase to one side of a T-type antenna and an antenna for matching impedance to the other side. CONSTITUTION:An antenna 3 provided above a heating wire 2 on a face of a plate glass 1 consists of the T-type 1st antenna 6 comprising a horizontal part 4 and a vertical part 5, the 2nd antenna 7 for adjusting phase made of one horizontal wire connected to one side of the vertical part 5 with its end folded back, and the 3rd antenna 9 for matching impedance having a stub 8 connected to the other side of the vertical part 5, and a power feeding point 10 is provided to the antenna 9 for matching impedance. In receiving an FM broadcast wave by using this antenna 3, the antenna 6 acts like a major antenna, the antenna 7 improves the average gain as well as the directivity characteristic and the provision of the antenna 8 allows the receiving sensitivity to be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a glass antenna for a vehicle, and more particularly to a glass antenna for a vehicle suitable for receiving radio waves provided on a window glass of an automobile.

In recent years, automobile window glasses equipped with heating stripes and zero antenna stripes have begun to be adopted. There are two types of these so-called anti-fog glass antennas.

The first type connects a heating filament and an antenna filament and uses the heating filament as an auxiliary antenna filament.

In the second type, for example, as shown in FIG. 1, a heating line 2 and an antenna line 3 are provided independently on the rear window glass l, and each function is provided separately.

However, in the first type described above, it is necessary to prevent the received radio waves from flowing through the ground of the heating wire to the ground, and the direct current supplied to the heating wire must be prevented from receiving radio waves. It is necessary to prevent it from flowing to the power supply terminal of the machine.

For this reason, the circuit is very complicated, and the feeder line has three
When a thin coaxial couple such as 0-2'V is used, there is a risk that a short circuit accident may occur due to the direct current during anti-fog heating. Another drawback is that radio noise is generated while the heating wire is being energized.

On the other hand, although the second type does not have the drawbacks of the first type, it has a major drawback of low average gain for FM broadcast radio waves and (1) broadcast radio waves. In particular, when receiving FM broadcast waves, the directional characteristics are strong as shown in FIG. 2, and depending on the direction of the vehicle, the gain decreases, making it difficult to receive 7M broadcasts. Note that FIG. 2 is a directional characteristic diagram of the antenna of FIG. 1 when the gain of the conventional whip antenna is set to dE, where F indicates the direction in which the vehicle is fixed, and the radial direction indicates the direction in which the radio waves arrive. Also, curve A is 80MHz, and song 90 is 83MH2.
, Curve No. 1 shows the case where 86MH2 FM constant radio waves are received.

It is an object of the present invention to provide a glass antenna for a vehicle, which is a second type in which a heating strip and an antenna strip are provided independently, and which improves the average gain for FM broadcast waves and also improves the directivity characteristics. In a glass antenna installed on the window glass surface of a car, the antenna has a T-shaped first antenna consisting of a horizontal part and a vertical part, and is connected to one side of the vertical part. a second phase adjustment plate having at least one horizontal line with a
This is achieved by providing a third antenna for impedance matching connected to the other side of the vertical part and providing a feeding point to the third antenna for impedance matching.

The present invention will be explained below based on the drawings.

FIG. 3 shows a glass antenna showing the first embodiment of the present invention.
This is an antenna pattern particularly suitable for receiving 7M broadcasting (horizontal polarization), where 1 is a glass plate forming, for example, the rear window of a car, and 2 is a heating strip provided on the plate glass 1.

】 is an antenna installed above the heating wire 2 on the plate glass surface, which includes a T-shaped Ml antenna 6 consisting of a horizontal part 4 and a vertical part 5, and one antenna connected to one side of the vertical part 5. A second antenna 7 for phase adjustment made of a horizontal filament whose end is folded back, and a third antenna 9 for impedance matching that has a stub 8 connected to the other side of the vertical part 5.
A feeding point lO is provided on the impedance matching antenna 9.

FIG. 4 shows a glass antenna according to a second embodiment of the present invention, and FIG. 5 shows a glass antenna according to a fifth embodiment of the present invention, and the reference numerals indicate the same as those in FIG. 3 (first embodiment).

When the vehicle glass antenna of the present invention receives FM broadcast waves, the 5T-type first antenna acts as the main antenna over the entire FM frequency range, and the 5T-type first antenna is provided on one side of the vertical part of the T-type antenna. The second antenna for phase adjustment eliminates the phase difference between the direct wave and the reflected wave from the car body, dog, building, human body, etc., improving the directivity characteristics and improving the average 11th gain. By providing the impedance of the antenna and the impedance of the entire feeder line (coaxial cable) (
75Q) to increase reception sensitivity, and by adjusting the connection position (tap) of the stub of the impedance matching antenna and the length of the main antenna, it is possible to improve the antenna gain and frequency characteristics. .

In the vehicle glass antenna with such a configuration, the third
The glass dimensions shown in the figure are A=1,100fnJn, A
' = 1,450mm, `` = 4'9omm, and the dimensions of each part of the antenna wire are M = 520mm, L = 530.
Cocoon, 'l=60mm, d=10rrm, 6=60■
, f = 3011B, X = 2601 + 1m, 7 =
500 listens, p-15, 9-15 scream, C-50 key, g
When we measured the directivity characteristics of the antenna using -30 questions, j = 10th tone, k-20th circle, and h-40th tone, we obtained the characteristics shown in Figures 6, 7, and 8. Ta.

Figure 6 shows 80 MHz, Figure 7 shows 83MH7, and Figure 8 shows 86M1 (F' M band directivity diagram in Z is shown by solid line (dotted line is 1m long whip antenna, dashed line is second antenna). ).As is clear from Figures 6, 7, and 8, the glass antenna of this example has extremely good omnidirectionality for radio waves arriving from any direction. It can also be seen that the receiving gain of this example is higher than the whip antennas shown in FIGS. 6, 7, and 8. However, if the average gain in the CM band is When the gain of the conventional glass shown in the figure is CM and B, the gain difference is +5.3+a at 80MH2.
B183MI (+7.8dB at z, 86MH2
It can be seen that the result is +2.7 dB and an average of +5.3 dB, which is a significant improvement.

Furthermore, in the antenna patterns of Examples f and l, there is no T-shaped first antenna 6, there is no second antenna 7 for phase adjustment, and there is no third antenna 7 for impedance matching.
The average gain in the CM band was actually measured when one end was connected to the vertical part in place of the antenna 9 and power was fed to the other end, and the gain of the antenna of the first embodiment was taken as OdB. When the T-type first antenna 6 is not used (when only the phase adjustment antenna 7 and the impedance matching diagram antenna 9 are used), the gain difference is -12.2 dB at 80 mm.
, 83. -12,5dB at MHz.

-9,8 (1,B, average -11,5 at 86MH2
dB, it can be seen that the first antenna contributes very greatly to the gain improvement and is the main antenna.

Next, when there is no second antenna 7 for phase adjustment (when there is only the first antenna 6 and the impedance matching antenna 9), -1.1 dB at 80 MHz, 83 M
-0.7dB at H2, -1 at 86MHz
, 5 dB, average -], ldB, but the 6th
Looking at the directivity diagrams without the phase adjustment antenna 7 shown in Figures 7 and 8, there is a deep drop in gain, which is due to the difference between direct waves and indirect waves from the ground, vehicle body, etc. This is thought to be based on the phase difference, and it can be seen that the second antenna for phase adjustment of the present application has the effect of eliminating the dip, contributing to the improvement of the directivity characteristics.

Next, the third filter for impedance matching. When replacing the antenna 9 with only a conductive wire, one end of which is connected to the vertical part 5, and power is supplied to the other end, -6.2 dB at 80 MH2,
At 83 MHz it is -9.9 dB, at 86 MH2 it is -5.3 dB, on average -7. I dB, and the third antenna contributes to gain improvement. When measured (indicates the impedance when there is no impedance matching antenna within 0, that is, when power is supplied with only 4 wires), at 80MH2, Re (pure resistance) = 227Ω (108Ω), Xs
(Reactance, + is inductive, - is capacitive) = -61
0 (+296Ω), Re=939 at 83MHz
(504Ω), X5=-99Ω(-4869), 86M
In H2, Re=83Ω(]33Ω), X5=-13
9 (-2410) and the pure resistance Re is approximated to 750, and the reactance 1 It can be seen that it works to fully demonstrate the

In particular, it sufficiently compensates for the drop in gain of the whip antenna, so it is very effective as a glass antenna for a so-called dyno-city reception antenna, which uses both a whip antenna and a glass antenna and switches to the antenna with the best reception condition. It is.

Next, the glass antenna shown in FIG. 4, which shows the second embodiment of the present invention, is similar to the antenna of the first embodiment except that the impedance matching antenna is replaced with an oven. When the average gain was actually measured and expressed as a gain difference when the gain of the antenna of the first embodiment was expressed as OdB, it was -0.6 dB at BOMHz, 83 M
-1,5dB in H2, +1 in 86MH2
．． 4 dB, average -0.2 dB, and it can be seen that similar characteristics are exhibited.

Next, the glass antenna shown in FIG. 5 showing the third embodiment of the present invention is obtained by adding one antenna with an open end as a phase adjustment antenna to the antenna of the first embodiment, so that L'= 500++++n and other dimensions (glass and antenna) are the same, and when the average gain in the CM band is actually measured and expressed as the gain difference when the gain of the antenna of the first embodiment is OdB, at 80MH2 -0,
7dB.

83MHz (+L8 dB at C, 86 MHz
The result is +0.4 dB at the peak, and +0.5 dB on average, indicating that the structure exhibits characteristics of stubble or better.

In the above example, the effect of this example was explained by specifying the dimensions of each part of the antenna wire and actually measuring the characteristics of the antenna. However, the dimensions of each part of the antenna wire were type (opening, angle of glass installation,
The optimum value may change depending on the length of the feeder, wiring location, etc. When receiving F''M waves in the range of 76 MHz to 90 MH2, the length M of the horizontal section that mainly operates as the main antenna is determined by the FM broadcasting frequency. Let the wavelength of
In the range of ~750 mm, the length L for phase adjustment is the same as M (λ/4)a±(λ/20)α, that is, 4
50~? In the range of 50rmn, y of the impedance matching antenna is ((λ/8)a (/l/20
) (Z) ~ ((λl/4) (2 + (λ/20) α), that is, in the range of 200 to 750 m, the capacity is increased for the length 1 of the folded part for phase adjustment. , the impedance has an effect over a wide band with less change, but when L is the resonance length, Q (= -) is high and the ωOR p gain is high, so in this case it is better not to fold back. However, in other cases, it is better to turn around J: (, 300w
In the range of n or less, the length
(in the case of the figure) other ds e, f, T', q
, Cs gs j, k, and h lengths may be appropriately selected from the optimum values within a range of at least 3 or more so as to reduce stray capacitance with other elements adjacent in parallel.

Although the present invention has been described above with reference to three embodiments, the antenna of the present invention is not limited to these examples, and the following modifications are also possible.

(1) The T-type main antenna wire is shown in Figures 9, 10 and 1.
As shown in FIG. 1, the horizontal portion may be composed of two or more filaments (FIG. 9), and the ends thereof may be folded back (FIG. 10).

Further, the vertical portion may also be configured to have two filaments instead of one, forming a T-shape or a loop (FIG. 11).

(2) The number of horizontal m stripes of the phase adjustment antenna is 1st.
The number of wires is not limited to one as shown in the figure, but more than one can be used as shown in FIG. 5, and they exhibit similar characteristics.

(3) The impedance matching antenna is shown in Figure 12.
i (' As shown in Figure 13, the stub shape as in the embodiment is of course possible, but it is also possible to use shapes as shown in Figures 14, 15, and 16. Here, the impedance is matched. It seems that the things that have the most effect on impedance matching are things other than electromagnetic wires, such as the tap-shaped ones or the U-shaped ones in Figure 14, but the conductive wires that can be connected to these also have no effect on impedance matching. In this specification, it is treated as a part of an impedance matching antenna because it does not function.

Further, in the embodiments of the present invention, the glass antenna is printed and baked with a tetraelectric paste, but it goes without saying that it may also be formed by embedding thin metal wires in the laminated window glass.

Further, in the embodiment of the present invention, an anti-fogging antenna having the heating strip 2 is shown, but the heating strip may not be provided, and the antenna of the present invention may be provided on the windshield.

As described above, the glass antenna of the present invention has the characteristics of a separate type that does not connect with the heating wire, and also eliminates the disadvantages of the separate type, has a high average gain over the entire FM frequency band, and has improved directional characteristics. It has the remarkable effect of being able to do the following.

[Brief explanation of the drawing]

Figure 1 is a plan view of a conventional glass antenna, and Figure 2 is a top view of a conventional glass antenna.
Fig. 3 is a directional characteristic diagram of the antenna shown in Fig. 3. 4 and 5 are plan views of a glass antenna showing one embodiment of the present invention, and FIGS.
Example) 80MHz, 83MHz, 8 respectively
Directional characteristic diagram at 6 MHz (the dotted line is a 1m long rear whip antenna, the one-dot chain line is the antenna of the first embodiment without the second antenna for phase adjustment), 9th
10 and 11 are modified examples of the first antenna of the present invention, FIG. 12, FIG. 13, FIG. 14, FIG.
FIG. 6 shows a modification of the third antenna of the present invention. 1...Plate glass, 2...Heating wire, 2...
antenna. 4.Horizontal part, 5.Vertical part, 6.1st
antenna. 7...12th antenna, 9...3rd antenna. 10...Power supply point diagram 1

Claims (1)

[Claims] In a vehicle glass antenna in which an antenna wire is provided on a plate glass surface, the antenna includes a T-shaped first antenna consisting of a horizontal part and a vertical part, and at least one horizontal antenna connected to one side of the vertical part. The second for phase adjustment consisting of conflict
and a third antenna for impedance matching connected to the other side of the vertical part, and a feeding point is provided at the third antenna for impedance adjustment. glass antenna.