JPS6072402A - Glass antenna for automobile - Google Patents

Abstract

PURPOSE:To increase the average reception gain and to improve the directivity characteristic to an FM broadcast radio wave by connecting an auxiliary antenna having phase adjustment and impedance matching to a short-circuit wire of the 1st main antenna and providing a lead point reaching a feeding point to one end of the 1st main antenna. CONSTITUTION:The 1st main antenna 3 is arranged laterally above a heat wire 2 on a face of a glass plate 1 and consists of the 1st horizontal wire 4, the 2nd horizontal wire 5 and the short-circuit wire 6 connecting the tips of the wires. The auxiliary antenna 7 is connected to the short-circuit wire 6 of the 1st antenna and to the lead point 10 of the 1st horizontal wire 4 with a conductor wire 9. The length M1 of the 1st horizontal wire acting like the main antenna 3 is preferably in the range of (lambda/4)a+ or -(lambda/20)a (where; lambda is the wavelength of an FM broadcast frequency and (a) is a shortening coefficient of wavelength, nearly 0.7) and the length M2 of the 2nd horizontal wire is preferably in the range of 40- 300mm.. Moreover, the length of the short-circuit wire (e) is preferably in the range of 10-50mm..

Description

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

In recent years, automobile window glasses equipped with heating stripes and antenna stripes have begun to be used. 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 1, and each function can be performed separately.

However, in the first type described above, it is necessary to prevent the received radio waves from passing through the ground of the heating wire and flowing to the ground, and the direct current supplied to the heating wire is It is necessary to prevent it from flowing to the power supply terminal. Therefore, the circuit is very complicated, and the feeder line requires only 3C! -2V'l) When using any thin coaxial cable, there was a risk of a short circuit accident due to the direct current during anti-fog heating. Also, while the heating wire is being energized,
It had the disadvantage of generating radio noise.

On the other hand, although the second type does not have the disadvantages of the first type, it uses FM broadcast waves and A to I
The major drawback was that the average gain for broadcast radio waves was low. In particular, when receiving 7M broadcast radio 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 the 7M broadcast. Note that FIG. 2 is a directional characteristic diagram of the antenna of FIG. 1 when the gain of the conventional whip antenna is OdB, where F is the fixed direction of the vehicle, and the radial direction loses the arrival direction of the radio wave. Also, curve A is 80 MHz, curve B is 83 MHz.
z and curve C show the case where 86 MHz 7M radio waves are received. .

In addition, the distance between the heating line and the upper edge of the window glass is usually 100 to 200 meters in the longitudinal center, but depending on the car model, it may be less than 100,111 meters, for example, 5 ollllllll.
There are some cases where the antenna has a small area, that is, the area occupied by the antenna is small, and which impedes the improvement of the reception gain of the glass antenna. In addition, in recent years, glass antennas in which the feeding point is placed on the side of the window glass have begun to be adopted for Type 2, as they have good directional characteristics (omnidirectional), but due to the structure of the car, wiring, etc. In some cases, it may be difficult to install it on the side of the window glass.

The present invention provides a second type in which heating stripes and antenna stripes are provided independently, and even if the distance between the heating strip and the upper edge of the window glass is relatively narrow, the average reception for 7M broadcast radio waves can be improved. The purpose is to provide a glass antenna for automobiles that has a feeding point at the upper center of the window glass, which has improved gain and directional characteristics. A first horizontal filament extending from the center to one side, a second horizontal filament provided on one side of the first horizontal filament, and a shorting line connecting the tips of the first horizontal filament and the second horizontal filament. Connect an auxiliary antenna with phase adjustment and impedance matching branch functions to the short-circuit line of the first main antenna that feeds from This is achieved by providing a

The above will be explained based on the drawings.

FIG. 3 shows a glass antenna showing the first embodiment of the present invention.
Especially l? Antenna suitable for receiving 'M broadcasts.
For example, the rear window of a car 1. −14′=,”y too, :+
pC),...=4to7-4G5+-y"'Qノ'
))+4)+DO=JJ=--Heating stripes provided on the Sl. A first horizontal filament 4 extending from the center to one side and a second horizontal filament 4 disposed horizontally above the heating filament 2 on the plate glass surface and a second horizontal filament 4 provided on one side. The 1.0 main antenna consists of a short-circuit line 6 that connects the filaments and their ends, and l is the horizontal filament whose tip that connects to the short-circuit line 6 of the first earth antenna is folded back to the j side. A feeding point 8 is provided at the vertical center of the upper part of the window glass, and a conductive wire 9 is connected to the end of the first horizontal line 4 (output point 10).
) is connected.

- Figure 4, Figure 5, and Figure 6 respectively show the gate 2 embodiment, the third embodiment, and the fourth embodiment of the present invention. The tip of the second horizontal line 5 is folded back and an auxiliary armrest is provided. is arranged above the first horizontal line 4. In Fig. 6 (fourth example), the first horizontal line 4
The shape of the short-circuiting filament connecting the second horizontal filament 5 and the second horizontal filament 5 is made straight (vertical filament), and each reference numeral indicates the same as in FIG. 3 (first embodiment).

FIGS. 7, 8, and 9 show glass antennas showing a fifth embodiment, a sixth embodiment, and a seventh embodiment, respectively, which are modified examples of the auxiliary antenna. Example) and equivalents are shown.

When the glass antenna of the present invention receives FM broadcast waves,
A relatively short second horizontal filament provided on the same side as the first horizontal filament extending from the center to one side over the entire ph4 frequency range, the first horizontal filament, and the tip of the M2 horizontal filament. The short-circuit wire connecting the main antenna and the empty antenna act as the main antenna, and by connecting the auxiliary antenna having at least one horizontal line to the short-circuit wire of the main antenna, the impedance can be matched and the direct wave By eliminating the phase difference with indirect waves caused by the vehicle body, the earth, buildings, human bodies, etc., it is possible to improve the directivity characteristics and also improve the average gain.

In the vehicle glass antenna with such a configuration, the third
The glass dimensions shown in the figure (first example) are A=i, oa
Column o, A is 1.510 lungs, B is 2595 lungs, and the dimensions of each part of the antenna are M+-= 535 rrnn, M2 ""
75 mm IL=1.060rran, ℃=25cm, f=lQg, d”7.5m+n, e+==7.5m+
++, e2=15mm, θ-2251=n (θ1+0
2), g-+ommi h=30m, d'=iom
When the directivity characteristics of the antenna were measured with m being 14J, the characteristics as shown in FIGS. 10, 11, and 12 were obtained. Figure 10 shows 80Wn2. Figure 11 is 8
3114Hz.

Figure 12 is a diagram of the directivity characteristics of the FM band in 86Wn2.
The solid line shows the glass antenna in FIG. 5, and the dotted line shows the case of only the first main antenna in FIG. Figure 1O,
As is clear from Figures 11 and 12, the auxiliary antenna acts to eliminate the dip in gain that would be caused by the phase difference between the direct wave and indirect wave when only the main antenna is used (dotted line). It can be seen that very good omnidirectionality can be obtained for radio waves arriving from any direction. In addition, the receiving gain of the Jth embodiment is 11", the average gain of the M band is 0clB, and the gain of the conventional glass antenna shown in FIG.
The gain when expressed as the difference is 80 respectively]
+4.5aB at.

+2.8 dE at 83Wn2, +2.9 dB at 86 MHz.

It can be seen that the average improvement is +3.4 cLB over a wide band. In addition, when the impedance of the glass antenna of the first embodiment was measured at the feeding point (for comparison, the impedance is shown in the case where there is no auxiliary antenna, that is, only the main antenna is within 0), it was found that at 80Wn2, Rs (pure resistance ) = 830 (42Ω), Xs (reactance, 10 is inductive, - is capacitive) --'42Ω
-969), Rθ = 35Ω (27Ω
), Xθ = -180 (-28 Ω), 71 Ω (90 Ω) at 8611 Hz, Xs = +30 Ω (+190), the pure resistance Re is 75 Ω, the reactance Xs is 0 Ω, and the auxiliary antenna It can be seen that the antenna functions to stably match the impedance across the entire F'M frequency band and fully exhibit the characteristics unique to the antenna. In particular, since the glass antenna of the present invention exhibits good omnidirectionality, it can compensate for the drop in gain of a ball antenna, and is suitable for diversity reception with a ball antenna.

Next, the second
Regarding the glass antennas of Example, Third Example, and Fourth Example, in FIG. 4, el = 92 = '7, 5
m, es = 15Wn, e = 30'mn Other dimensions of the 30th glass and dimensions of each part of the antenna are the dimensions of the first embodiment shown in Fig. 3 (A, A', B, M, , M2 ,L,
The average gain in the M band is measured using the same value as fi, f 1 0% gs h,"), and is expressed as the gain difference when the gain of the antenna of the first embodiment is set to OdB. Values as shown in Table 1 were obtained.

As is clear from Table 1, it can be seen that all exhibit properties equivalent to or better than those of the first example.

Next, regarding the modified examples of the auxiliary antenna shown in FIG. 7 (fifth embodiment), FIG. 8 (sixth embodiment), and FIG. 9 (seventh embodiment), d = d2 = 7.5 twm (Only in the fifth embodiment, d = 7, 5 rrrm), e, = θ2
= 7.5mm (e++=15m only in the fifth embodiment)
, e=15 mm (only in the fifth example, e=22,5
mm ), LH = L2 = 530 m +++ Binding, other glass dimensions, and dimensions of each part of the antenna are shown in Figure 3 (Figure 1).
The average gain in the 7M band was measured using the same glass antenna as in Example), and the gain difference is shown in Table 2 when the gain of the antenna in %Fyl Example is set to OdB. A value was obtained.

As is clear from Table 2, it can be seen that both exhibit properties equivalent to those of the first example.

In the above embodiment, the effects of this embodiment were explained by specifying the dimensions of each part of the antenna and actually measuring the characteristics of the antenna. However, the optimum dimensions of each part of the antenna may vary depending on the type of vehicle (opening, angle of glass mounting, feeder length, wiring location, etc.) When receiving broadcast waves, the length Ml of the first horizontal line that operates as the main antenna is determined by, for example, (λ/sα±(λ/20) a (α
is the wavelength shortening rate of the glass antenna, which is approximately 0.7), or 4
The optimum value may be appropriately selected within the range of 50 to 85011I+1, and the length M2 of the second horizontal line may be determined by the third
FIG. 13 (I: 80 MHz) shows the change in reception gain when changing M2 while keeping the dimensions of each part other than M2 the same in the crow antenna shown in the figure (first embodiment).

I [: 83 MHz%m: 86 Mn2), it is clear that it is preferably within the range of 40 to 300 IllI11.

By forming a stub with the first horizontal line and/or the auxiliary antenna line, the second horizontal line may be
It improves the current and current of the received radio waves and compensates for the shift in the resonance point in the case of wideband reception.

It is presumed that it has the effect of As is clear from Tables 1 and 2, it is preferable to provide a higher gain.

It has also been confirmed that the shorting line e is preferably within the range of 10 to 50 lines. In this case, the shape of the shorted voice is not only a straight line (vertical line) as shown in Figures 5 and 6, but also a d-shape as shown in Figures 3, 7, 8, and 9. , it may be of one shape as shown in FIG. Also,
In each of the embodiments, the power supply point and the extraction point are arranged on the vertical side of the □ window glass.

It has been confirmed that even if they are placed 100,111 m apart to the right (the length M of the first horizontal line is also changed at the same time), the same gain as in each example can be obtained.

Next, the auxiliary antenna having the capability of phase adjustment and impedance matching should have a length t of at least 950 to 1,160 mm.
Although it is necessary to generate horizontal filaments in the range of mm, horizontal filaments of similar length may be added or the tips thereof may be folded back, and the sound is limited to those of the examples. It can be selected as appropriate.

The glass antenna of the present invention is suitable for cases where heating strips for anti-fogging are placed side by side on the rear window glass of an automobile, and when the distance between the heating strips and the edge of the window glass is narrow. The present invention is not limited to this, but it may be a single Athena wire without heating striations, or a step wall may be provided on the front window glass.

As described above, the glass antenna of the present invention is a separate type that is not connected to the heating wire, occupies a small antenna area on the window glass of an automobile, and can transmit signals throughout the entire FM broadcast area even under the disadvantageous condition of central feeding. This has the remarkable effects of improved directional characteristics and high average gain.

[Brief explanation of drawings]

Figure 1 is a plan view of a conventional glass antenna, and Figure 2 is a top view of a conventional glass antenna.
3 to 9 are plan views of a glass antenna showing an embodiment of the present invention, and FIGS.
Mn2.83 Mn2. The directional characteristic diagram at 86 MHz, FIG. 13, is a diagram showing the change in reception gain when the length M2 of the second horizontal line constituting the first main antenna is changed in the antenna of FIG. 3. 100. Plate glass, 201. Heating streaks, Dan 19. 1st main primary, 461. ] Horizontal striations, 5. ,,second horizontal striation 610. Short circuit wire, 111. Auxiliary antenna, 800.
Feeding point 10... Output point patent applicant Central Glass Co., Ltd.

Claims (1)

[Scope of Claims] (Li) In a glass antenna for a vehicle in which an antenna strip is provided on a plate glass surface, a first horizontal strip extends from the vertical center of the plate glass to one side, and a first horizontal strip is provided on the one side. A first main antenna consisting of a second horizontal filament and a shorting line connecting the tips of the first horizontal filament and the second horizontal filament, and a second auxiliary antenna connected to the shorting line of the first antenna. 1. A glass antenna for an automobile, characterized in that a feeding point or a lead-out point to the feeding point is provided at one end of a first main antenna in the vertical center of the plate glass. (2) The length of the first horizontal filament in the first main antenna is (v4) a±(λ/20) α (λ: wavelength of the receiving frequency, a wavelength shortening rate of the Nigaras antenna), the second The length of the horizontal line is 40~3oomm, and the length of the short line is 10~30mm.
2. The glass antenna for an automobile according to claim 1, characterized in that the glass antenna has a diameter of 50 mm.