JPS61222302A - Wind glass antenna for automobile - Google Patents

Abstract

PURPOSE:To double the area of a window glass by providing a couple of antenna element groups constituting antenna wires of parallel feeding type while being divided to two parallel faces formed by the window glass. CONSTITUTION:A parallel feeding type antenna comprising antenna element groups 2a, 2b in pairs being symmetrical or nearly symmetrical is arranged to a front face 1a and a rear face 1b of the rear window glass 1 while being divided into two in a folded way. Thus, it is possible to use the antenna while the area of the window glass 1 is doubled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automobile window glass antenna, and in particular to a VHF antenna.
Alternatively, it is most suitable for receiving UHF band TV broadcast waves.

[Conventional technology]

2. Description of the Related Art Conventionally, it is known that an antenna wire for receiving radio broadcast waves is attached to the inner surface of a rear window glass of an automobile along with a heater wire for preventing fogging. This antenna wire is generally tuned to obtain good reception output in the AM and FM bands, and in order to receive TV broadcast waves, a dedicated antenna tuned for TV is separately required.

However, TV broadcast frequencies range from a low band (90 to 180 MHz for the first to third channels) to a high band (170 to 222 MHz for the fourth to twelfth channels), requiring a very wide band antenna. Window glass antennas currently in use can receive good reception in a relatively narrow FM band (70 to 90MHz), but no matter how tuned they are, they cannot provide satisfactory performance for the entire TV broadcast band. The reality is that it cannot be done. Moreover, the area of the rear window glass is limited, and heater wires must be attached or in order to ensure rearward visibility,
The location and area of antenna wires are often restricted. Therefore, the shape of the antenna is limited, and it is difficult to attach a high-sensitivity, broadband antenna wire with a large number of elements to a window glass.

[Problem that the invention seeks to solve]

In view of the above-mentioned problems, an object of the present invention is to provide a windowpane antenna for an automobile that has excellent characteristics of high sensitivity and wide band, and can also receive VHF and UHF TV broadcast waves.

[Means to solve problems]

The automotive windowpane antenna of the present invention is obtained by dividing a pair of antenna elements (2a, 2b) of substantially similar shapes constituting one balanced feeding type antenna wire into two parallel planes formed by the windowpane. It is characterized by the fact that it has been provided. With this configuration, the area of the window glass can be doubled and a high-sensitivity, broadband antenna wire can be attached.

〔Example〕

FIG. 1 is a diagram showing an antenna pattern on the rear window glass surface of an automobile, showing an embodiment of the window glass antenna of the present invention. In this embodiment, the front surface 1a and the back surface 1b of the rear window glass 1 are
An antenna element is attached to the antenna element using a silver paste printing method or the like. The antenna element group 2a on the front side and the antenna element group 2b on the back side constitute one parallel feeding type antenna as a pair, and a pair of feeding points 3a, 3 provided on the front side and the back side
Receives balanced power from b. That is, a balanced feeding type antenna consisting of a pair of symmetrical or substantially similar antenna element groups is folded into two and arranged on the front surface 1a and the back surface 1b of the rear window glass 1.

The antenna pattern of FIG. 1 is a log-periodic antenna in which each vertical element a is arranged in a predetermined ratio.

The length and spacing of b have been varied. Each of the antenna element groups 2a and 2b on the front surface 1a and the back surface is symmetrical with respect to the center line of the rear window glass 1, and the element lengths are gradually shortened from the center toward both sides. Note that when the longest element a is placed at the center of the front surface 1a, the second element is placed on the back surface 1b, and the third element is placed on the front surface 1a again...
They are arranged alternately like ---1------m--... That is, the antenna element groups 2a and 2b have substantially similar shapes on the front surface 1a and the back surface 1b. In addition, if the element length exceeds the vertical width of the rear window glass l,
As shown in FIG. 1, the tips of the vertical elements a and b can be bent at right angles to extend to both sides in the horizontal direction.

The received outputs derived from the respective feeding points 3a and 3b in FIG. 1 are converted into unbalanced outputs by a balun 3 as shown in FIG. 2, and are output through a coaxial feeder line 4 to, for example, a TV tuner. Note that the output may be directly output to the tuner using a parallel feeder line without converting to an unbalanced output.

3 is a frequency characteristic diagram of the VHF band of the window glass shown in FIG. 1, and FIG. 4 is a frequency characteristic diagram of the FM band.

As shown in FIGS. 3 and 4, very high sensitivity and wideband reception characteristics can be obtained. Although not shown in FIG. 3, the receivable frequencies extend to the U) (F band), and it is also possible to receive TV broadcasts in the UHF band.

5 and 6 show a method of arranging antenna elements when the weather resistance of the antenna element 3a on the front side of the window glass 1 is a problem. In the example shown in FIGS. 5 and 6, two pieces of temporary glass 6.7 are bonded with an adhesive intermediate layer 8 such as polyvinyl butyral.
It uses laminated glass that is bonded together through In FIG. 5, the antenna element groups 2a and 2b are provided on the front surface 6a and the back surface 6b of the temporary glass 6 on the inside of the vehicle. Further, in FIG. 6, an antenna element group 2b is attached to the front surface 6b of the glass plate 6 on the inside of the vehicle, and an antenna element group 2a is attached to the back surface 7b of the temporary glass 7 on the outside of the vehicle.

Each element group 2a, 2b is insulated by an adhesive intermediate layer 8. According to the configurations shown in FIGS. 5 and 6, the antenna element 2a is not exposed to the outside of the vehicle, so there is no problem with weather resistance.

7 and 8 show modified examples of the antenna pattern. FIG. 7 shows an arrangement in which almost completely symmetrical logarithmically periodic antenna element groups 2a and 2b are divided into a front surface 1a and a back surface 1b. Further, FIG. 8 shows a log-periodic antenna that is almost the same as that in FIG. 7, but in this example, the elements are arranged alternately on the front surface 1a and the back surface 1b in order of length. Therefore, each antenna element group 2a, 2b is not symmetrical but similar.

In the above embodiment, the antenna element groups 2a and 2b are attached to the front and back surfaces of the rear window glass 1, but if there is a fixed fitted window glass (rear window glass) on the side of the vehicle that cannot be opened freely, , antenna elements may be arranged on the front and back surfaces of the antenna to receive balanced power feeding.

〔Effect of the invention〕

As described above, in the present invention, the pair of antenna elements constituting the balanced feeding type antenna wire is divided into two parallel planes formed by the window glass, so the area of the window glass can be doubled and used. This makes it possible to attach a high-sensitivity, wideband antenna line with a large number of elements even when the window glass area is small compared to the area occupied by the antenna, or when the antenna installation position on the window glass surface is limited. It becomes possible.

[Brief explanation of the drawing]

Fig. 1 is a pattern diagram of an automobile rear window glass antenna showing an embodiment of the present invention, Fig. 2 is an output circuit diagram of the antenna of Fig. 1, and Figs. 3 and 4 are diagrams of the antenna of Fig. 1. VH
Frequency characteristic diagrams of the F band and FM band, Figures 6 and 7 are cross-sectional views of the glass when antenna elements are attached to laminated glass, and Figures 7 and 8 are Figure 1 showing modified examples of the antenna pattern. FIG. 3 is a pattern diagram of a rear window glass surface similar to that shown in FIG. In addition, in the symbols used in the drawings, l-...-1 to -1...Rear window glass la
−−−−・−・・Surface 1b・−・−−−−−
---Back surface 2a, 2b...-Antenna element group 3------------Balun 4--
−−−−−・−m−−−・・−Coaxial feeder line 6.7−
・−−−−−−−・・Plate glass 8−・−・−−−−−−
- Adhesive intermediate layer.

Claims (1)

[Claims] 1. A pair of antenna elements of substantially similar shape constituting one balanced feeding type antenna strip is divided into two parallel planes formed by a window glass. Automotive window glass antenna. 2. The automobile window glass antenna according to claim 1, wherein the antenna wire has a logarithmically periodic antenna pattern.