JPH0368562B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an antenna glass in which an antenna wire is disposed on an automobile window glass, and in particular,
This invention relates to an automobile antenna glass that maintains good reception performance when FM broadcast waves to be received span a wide band on the high frequency side. [Prior Art] In general, whip antennas are widely used as antennas for automobile radio receivers, but since this type of antenna becomes an external protrusion relative to the vehicle body, there is a method to avoid this. Recently, so-called antenna glasses, in which antenna wires are disposed on the rear glass or front window glass of automobiles, have begun to appear. Taking a rear window glass as an example of this type of antenna glass, for example, as shown in FIG. 9, a heater wire H is usually disposed on the rear window glass 1 of an automobile as a heater member for defogging. Furthermore, an antenna wire A for receiving FM broadcast radio waves is provided, for example, in the upper region of the rear window glass 1 so as not to interfere with the heater wire H. This type of antenna wire A connects one end of the main antenna wire 3 extending along the substantially lateral direction of the window glass 1 to the feeding point 2, and the main antenna wire 3 is connected above the main antenna wire 3 to the feeding point 2. A first sub-antenna line 4 is arranged substantially in parallel, and a connecting line 5 for phase adjustment connects the middle part of the first sub-antenna line 4 and the other end of the main antenna line 3. It was designed to connect with In FIG. 9, reference numeral 6 indicates a substantially inverted L-shaped auxiliary antenna wire provided at one end of the main antenna wire 3. For example, an AM antenna wire A1 is disposed below the antenna wire A, and this type of AM antenna wire A1 includes, for example, a plurality of antenna wires 7 substantially parallel to the main antenna wire 3. , 8 are arranged, and each antenna wire 7, 8 is connected by a suitable connecting wire 9. In such antenna glass, for example
The phases of the sub-antenna wire 4 and the main antenna wire 3 are matched by the connecting wire 5 in the low frequency band of FM broadcast radio waves, and the phase of the sub-antenna wire 4 is matched with respect to the sub-antenna wire 4 in the high frequency band. If the connecting wire 5 is made to function as a reactance element,
The main antenna filament 3 and the sub antenna filament 4 are as described above.
It is possible to receive the FM broadcast radio wave band appropriately, and the AM antenna wire A1, together with the main antenna wire 3, can secure a certain reception area as a whole, so it is possible to receive the AM broadcast radio wave band appropriately. This allows efficient reception. [Problems to be solved by the invention] However, with such conventional antenna glass, it is difficult to obtain a certain degree of sufficient gain and omnidirectionality for the domestic FM broadcast radio wave band (76 to 90 MHz). However, it has been found that it is difficult to obtain sufficient gain for the high-frequency and wide-band FM broadcast radio wave band (88 to 108 MHz) such as in the United States. In order to solve such problems, it is possible to improve the antenna gain by using an amplifier for amplification, but since the problem of cross modulation will inevitably appear when using an amplifier, there is no solution. It is not desirable as such. For this reason, the inventor of the present application was considering various antenna patterns that could obtain high gain without an amplifier, and found that the three main antenna wire portions that constitute antenna wire A contributed to widening the antenna performance and increasing the gain. We have come to the conclusion that this is the case, and have devised the present invention. [Means for Solving the Problems] The present invention has been made by focusing on the above problems, and is applicable to cases where the FM broadcast radio wave band to be received is high frequency and covers a wide band. Another object of the present invention is to provide an antenna glass for automobiles that allows high gain to be obtained without using an amplifier. That is, the present invention provides an antenna glass for an automobile in which an antenna wire is disposed on a window glass for an automobile, in which the antenna wire is a main antenna connected to a feeding point and extending substantially in the lateral direction of the window glass. a wire, and a sub-antenna wire connected to the main antenna wire via a connecting wire for phase adjustment and extending substantially in the lateral direction of the window glass, both ends of the main antenna wire. Nearby, there is a folded line towards the center of the main antenna line.
The tip of each folded line is an open end. In such technical measures, there are no particular restrictions on the type of window glass for a car, but a rear window glass is preferable from the viewpoint that it does not significantly affect visibility from inside the vehicle. In addition, the materials for the antenna wire include conductive metal powder such as Ag, Al, Pd, or other conductive substance powder, glass frit,
A conductive paste is produced by mixing a binder and other desired additives, and the conductive paste is baked onto a glass plate in the form of thin stripes in a predetermined pattern using a screen printing method or the like. In addition, various other conductive materials can be used as appropriate. Furthermore, as a mounting surface for the antenna wire, for types where the window glass is made up of a single glass plate, the antenna wire is usually attached to the surface of the window glass, but it is possible to attach multiple glass plates together. In the case of a type of window glass that is made of so-called laminated glass, antenna wires may be interposed not only on the surface of the window glass but also between the glass plates.
In this case, the antenna wire is not exposed on the window glass surface, which is desirable from the viewpoint of protecting the antenna wire. Furthermore, regarding the pattern of the antenna wire, it is sufficient that it includes at least a pair of folded wires in addition to a main antenna wire, a sub antenna wire, a connecting wire for phase adjustment, and other appropriate auxiliary antenna wires. The design may be changed as appropriate, such as by attaching a strip or changing the arrangement or dimensional relationship of each antenna strip, but at least the effective length of the main antenna strip can receive the desired reception frequency band with good performance. As shown, the length range is determined by (wavelength of desired frequency x 1/4) x (shortening rate of antenna glass) ~ (wavelength of desired frequency x 1) x (shortening rate of antenna glass). is particularly preferred. For example, the above-mentioned main antenna wire has a length of {2780 mm/4 (1/4 wavelength of 108 MHz) x
0.64 (shortening rate of antenna glass)} ~ {3060mm
(1 wavelength of 98MHz) x 0.64 (same as above)}, that is, approximately 440 mm to 1960 mm. should receive
{3060 mm/4
(1/4 wavelength of 98MHz) x 0.64 (shortening ratio of antenna glass) -440mm} ~ {3410mm (1 wavelength of 88MHz) x
0.64 (same as above) - 440mm), i.e., abbreviated
A range of 50 mm to 1740 mm is particularly preferred. In addition, regarding the connecting wire, the phase of the radio wave signal received by the main antenna wire and the sub antenna wire is matched in the low band band, and the phase of the radio wave signal received by the main antenna wire and the sub antenna wire is matched in the high band band. It is particularly preferred to design the connecting wire so that it functions as a reactance element. Furthermore, it is necessary to design the above-mentioned folded filament so as to expand the practical reception area of the main antenna filament.
It has a connection point in the range of ~300 mm, and each folded wire is arranged at a position 5 to 100 mm away from the main antenna wire, and the dimensions between the ends are arranged 10 to 1000 mm apart. It is necessary to do so. Furthermore, in the case where an auxiliary antenna wire is provided in addition to the basic pattern of the antenna wire, the design of the auxiliary antenna wire may be changed as appropriate, such as a substantially T-shaped one or a substantially L-shaped one;
In order to further improve the matching with the load impedance of a radio receiver or the like, a matching element for input impedance matching may be interposed between the main antenna wire and the feeding point. [Operation] According to the above-mentioned technical means, since the pair of folded wires are arranged apart from each other near both ends of the main antenna wire, radio waves are not re-radiated from the main antenna wire during reception. However, most of these re-radiated radio waves will be received again at the folded wire section, which will reduce the radio wave loss and, as a result, expand the effective reception area of the main antenna wire section. It is thought that this serves to increase the gain of the main antenna wire portion. [Example] Hereinafter, the present invention will be described in detail based on the example shown in the accompanying drawings. ◎ Example 1 In this example, an anti-fogging heater wire H is disposed approximately in the center of the rear window glass 1 of an automobile, and the upper region of the window glass 1 located above the heater wire H Conductive paste on the surface,
For example, an antenna wire A having a predetermined pattern printed by baking with silver paste is provided. The antenna wire A has a feed point 2 on one side below the upper region of the window glass 1, and a main antenna wire 3 having one end connected to the feed point 2 and extending substantially in the lateral direction of the window glass 1. , a sub-antenna line 4 disposed above the main antenna line 3 substantially in parallel with the main antenna line 3, and a phase adjusting line 4 that connects the main antenna line 3 and the sub-antenna line 4. It has a basic pattern consisting of connecting filaments 5. In this basic pirn, both ends of the connecting wire 5 are connected to intermediate portions of the main and sub antenna wires 3 and 4, and have two bent portions 5a and 5b. Further, a first folded wire 11 toward the center of the main antenna wire 3 is connected near the end of the main antenna wire 3 on the feeding point 2 side, while a first folded wire 11 toward the center of the main antenna wire 3 is connected to the other end of the main antenna wire 3. Similarly, a second folded filament 12 directed toward the center of the main antenna filament 3 is connected, and the tips of each folded filament 11 and 12 are mutually open ends. In addition, the above-mentioned sub-antenna wire 4
Folded filaments 15 and 16 directed toward the center of the sub-antenna filament 4 are connected to both ends of the auxiliary antenna filament 4, respectively, and each of the folded filaments 15 and 16 are arranged facing each other and appropriately spaced apart from each other. It has folded parts 17 and 18 which are folded back into a substantially L-shape. Further, in this embodiment, a substantially inverted T-shaped AM antenna wire A2 is connected to the heater wire H at a substantially central portion of the main antenna wire 3, and connects the heater wire H to the AM antenna wire A2. The structure is adopted so that it can also be used as part of the antenna wire. More specific dimensions of each part are as follows.
Note that the symbol M in FIG. 1 indicates the vertical center line of the window glass 1. a1=540, a2=510, a3=505, a4=505, a5=
50, a6=25, a7=60, a8=30, a9=25, a10=
360, a11=440, a12=440, a13=50, a14=490,
a15=490, a16=25, a17=340, a18=340, a19
=220, a20=25, a21=15 (unit: mm) ◎ Example 2 The antenna wire A in this example has almost the same pattern as in Example 1, but
Unlike in the first embodiment, the connecting wire 5 for phase adjustment is bent in the opposite direction to that of the first embodiment, and furthermore, the sub-antenna wire 4 has folded wires 2 in a substantially inverted L shape at both ends.
1 and 22 are arranged facing each other and spaced apart from each other, and a substantially T-shaped auxiliary antenna wire 23 is connected to the tip of one of the folded wires 21. More specific dimensions of each part are set as follows. b1=540, b2=555, b3=390, b4=340, b5=
50, b6=25, b7=30, b8=90, b9=25, b10=
270, b11=370, b12=425, b13=25, b14=430,
b15=160, b16=350, b17=350, b18=25, b19
= 270, b20 = 25, b21 = 15 (unit: mm) ◎ Comparative example This comparative example is equipped with the conventional antenna pattern shown in Figure 9, and the specific dimensions are set as follows. . c1=200, c2=400, c3=480, c4=10, c5=30,
c6 = 50, c7 = 60 (unit: mm) ◎ Comparison of reception performance between Examples 1 and 2 and the comparative example. As shown, the vehicle C is rotated 360 degrees from the reference position S _O , and the reference position S _O side is set at a predetermined frequency (88 to 88).
FM broadcast radio waves (108 MHz) were transmitted in a uniform electric field of 60 dBμ/m, and the reception sensitivity level (unit: dBμ) corresponding to each position of the car was measured. As a result in this case, the average receiving sensitivity level (MEAN), minimum receiving sensitivity level (MIN), and directivity (minimum receiving sensitivity level subtracted from the average receiving sensitivity level) of Examples 1 and 2 and the comparative example are as follows. The changes in the average receiving sensitivity level at each frequency are shown in the graph shown in FIG. 4. In FIG. 4, □ indicates the results of Example 1, × indicates the results of Example 2, and △ indicates the results of Comparative Example.

[Table] When the reception performance of the antenna glass according to each example is evaluated based on the above table and graph, it is found that the reception sensitivity level of each example is higher than that of the comparative example. (47 dBμ on average), it is understood that these antenna patterns can provide a high-gain antenna glass without an amplifier. In addition, although the directivity of each example is slightly sharper than that of the comparative example, it is not extremely sharp, so there is a situation where the omnidirectionality of the antenna glass of each example is extremely impaired. is also avoided. ◎ Modifications Figures 5 to 8 show modifications of each of the above embodiments.
The antenna wire A2 is arranged close to the heater wire H, so that the heater wire H can also be used as an antenna for receiving AM broadcast radio waves. However, the present invention is not limited to this.
Antenna wire material A for receiving AM broadcast radio waves regardless of
3 may be provided, or the AM
There is no problem even if antenna wires A2 and A3 for receiving broadcast radio waves are provided. Further, the auxiliary antenna wires attached to the auxiliary antenna wires 4 are not limited to the patterns shown in the above embodiments,
In addition to the pattern shown in Example 1, a substantially T-shaped auxiliary antenna wire 24 may be added, only one substantially T-shaped auxiliary antenna wire 23 may be provided, or a substantially T-shaped auxiliary antenna wire 24 may be provided on the opposite side from Example 2. The design may be changed as appropriate, such as by connecting a letter-shaped auxiliary antenna wire 23. Furthermore,
In each of the embodiments described above, the antenna wire A is arranged above the heater wire H, but the antenna wire A of each of the above patterns may be arranged below the heater wire H. In this case, it has been experimentally confirmed that especially when applied to the rear window glass of a lift bag or hatchback type that can be opened and closed, particularly good reception performance can be obtained compared to the case where it is placed above the heater wire H. has been done. Furthermore,
By interposing a matching element 30 for impedance matching between the main antenna wire 3 and the feeding point 2, it is possible to more easily match the load impedance of a radio receiver or the like and the input impedance. This will further improve the reception performance of the antenna glass. [Effects of the Invention] As explained above, according to the automotive antenna glass according to the present invention, even when the FM broadcast radio wave band to be received spans a wide band on the high frequency side, sufficient reception can be achieved without an amplifier. Gain can be ensured, and the receiving performance of the antenna glass can be kept good accordingly.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing Example 1 of the automotive antenna glass according to the present invention, seen from the inside of the vehicle, and FIG. 2 is similar to FIG. 1 showing Example 2 of the automotive antenna glass according to the present invention. Fig. 3 is an explanatory drawing showing an example of a method for measuring the reception performance of the antenna glass according to each example, and Fig. 4 shows the average in each frequency band of each example and comparative example (conventional example). 5 to 8 are explanatory diagrams similar to FIG. 1 showing various modifications of the automotive antenna glass according to the present invention, and FIG.
The figure is an explanatory view showing an example of a conventional antenna glass for an automobile, viewed from inside the vehicle. Explanation of symbols, A...Antenna wire, 1...Rear window glass (window glass), 2...Feeding point, 3...Main antenna wire, 4...Sub antenna wire, 5...Connection wire, 11, 12...Folded lines.

Claims (1)

[Scope of Claims] 1. In an automobile antenna glass in which an antenna wire is disposed on the automobile window, the antenna wire is a main antenna wire that is connected to a feeding point and extends substantially in the lateral direction of the window glass. and a sub-antenna line connected to the main antenna line via a connecting line for phase adjustment and extending substantially in the lateral direction of the window glass, at least near both ends of the main antenna line. An antenna glass for an automobile, characterized in that the antenna glass is provided with a folded line extending toward the center of the main antenna line, and the tip of each folded line is an open end. 2. An antenna glass for an automobile according to claim 1, characterized in that a substantially T-shaped auxiliary antenna wire is attached to either the main antenna wire or the auxiliary antenna wire. 3. Claim 1, wherein the main antenna wire is connected to the feed point via a matching element for input impedance matching.
The antenna glass for an automobile according to any one of Items 1 and 2.