JPH0363842B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an antenna provided on a glass surface,
In particular, it relates to an antenna installed on the glass surface of a car for radio or TV reception.

2. Description of the Related Art Conventionally, it has been known that a rear window glass of an automobile is provided with a plurality of anti-fog heating conductive wires and an antenna wire for radio reception. Although these car radio receiving antennas can receive medium waves relatively well, they are directional when it comes to ultra-high waves such as FM broadcasts, and the FM may vary depending on the direction of the car.
Since it has the disadvantage of making it difficult to receive broadcasts, antennas with various antenna patterns are used to reduce the directivity.

For example, a rear window glass of an automobile has a plurality of heating conductive wires attached horizontally to the surface thereof, and a plurality of antenna conductive wires parallel to the heating conductive wires, and the antenna conductive wires are parallel to the heating conductive wires. A main antenna consisting of three parallel wires in upper, middle, and lower stages connected to each other as if a single straight line was bent, and one wire each placed on the upper and lower sides of the main antenna. The lower auxiliary antenna line and the lower main antenna line are connected by a connecting line near the vertical center line position of the window glass, and the center line of the upper auxiliary antenna The line position and the position of the middle main antenna line away from the center line position are connected by a connecting line that is bent to each other, and the upper main antenna line is connected to the upper auxiliary antenna line at a predetermined length. Antennas are known that are provided on a glass surface that extend close to each other across the glass surface to near the center line.

Such antennas installed on the surface of the rear window glass of automobiles usually have no dip point in reception sensitivity in all azimuth angles, and can obtain nearly circular omnidirectional characteristics with no uneven reception level. However, depending on the type and model of the car, there is a drawback that the directivity appears strongly only at specific reception frequencies.

The present invention eliminates such strong directivity at a specific receiving frequency and provides an antenna provided on a glass surface that has no directivity over the entire receiving frequency band.

That is, the present invention has a plurality of heating conductive wires attached horizontally to the surface of a window glass, and a plurality of antenna conductive wires parallel to the heating conductive wires, and the antenna conductive wires are parallel to the heating conductive wires. The main antenna consists of three parallel lines, top, middle, and bottom, which are connected to each other so that the lines are bent from a single straight line, and one each is arranged above and below the main antenna. The lower auxiliary antenna wire is connected to the lower main antenna wire by a connecting wire near the vertical center line position of the window glass, and the upper auxiliary antenna wire is connected to the lower main antenna wire near the vertical center line position of the window glass. The centerline position and the position of the middle main antenna line away from the centerline position are connected to each other by a first bent connecting line, and the upper main antenna line is connected to the upper auxiliary antenna line. In the antenna which is extended to the vicinity of the center line in a state of closely facing each other over a predetermined length, there is a gap between the lower auxiliary antenna filament and the uppermost filament of the heating conductive filament. A second bent connecting line is capacitively coupled to face the auxiliary antenna, and has one end connected to a position away from the centerline position of the uppermost filament, and a second bent connection line connected at the other end near the centerline position. An antenna provided on a glass surface characterized in that a coupling element is provided parallel to the auxiliary antenna connected thereto.

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, a heating conductive wire group 2 for preventing fogging is provided on a rear window glass 1 of an automobile, and power is supplied from a battery 3 via busbars 4, 5, and 6. An antenna wire group 7 is provided above these conductive wire groups 2, and received radio waves are guided from a feeding wave 8 to a preamplifier 9. In order to effectively utilize the induced power from the heating conductive wire group 2, a chiyoke coil 10 having high impedance in the radio frequency band is interposed between the heating conductive wire group 2, the battery 3, and the ground point. It will be done. Further, a decoupling capacitor 11 is inserted between the output line of the battery 3 and the ground point to prevent noise on the power supply line from being mixed into the received signal.

The method of feeding power to the heating conductive wire group 2 is to disconnect the grounding of the bus 6, connect the bus 4 and the bus 6, apply a heating current from there, and ground the bus 5 via the chiyoke coil 10. Can be transformed.

On the other hand, the antenna wire group 7 is composed of a main antenna consisting of three mutually parallel antenna wires 12a, 12b, 12c, auxiliary antenna wires 13a, 13b connected to the main antenna, and an auxiliary element 14. ing.

The middle main antenna wire 12b extends horizontally from the feed point 8, and its tip side is bent downward, and then folded back in parallel to connect to the lower main antenna wire 12c. Upper main antenna wire 1
2a extends upward from the power supply line 8, is further folded back in parallel, and reaches approximately the center of the window glass 1.

The auxiliary antenna wire 13a is the main antenna wire 12
This main antenna line 12a is provided on the upper side of a.
and are closely opposed to each other over a predetermined length.

The auxiliary antenna wire 13a is arranged almost symmetrically with respect to the central axis 17 (dotted chain line) of the window glass 1, and the middle point thereof is the middle main antenna wire 13a.
It is connected to a position away from the central axis 17 of the main antenna line 12b via a connecting line 15 which is parallel to the main antenna line 12b and has both ends bent. Also, the lower auxiliary antenna 13
b is arranged below the lower main antenna line 12c, and is connected to the main antenna line 12c at the central axis 17 of the window glass 1.

A lower auxiliary antenna wire 1 is provided between the lower auxiliary antenna wire 13b and the uppermost wire of the heating conductive wire group 2.
The coupling element 14 facing parallel to the window glass 1
are arranged almost symmetrically with respect to the central axis 17 of
The intermediate point thereof is connected to a position offset from the central axis 17 of the uppermost filament of the heating conductive wire group 2 via a connecting wire 16 that is parallel to the coupling element 14 and has both ends bent. The coupling element 14 and the connecting wire 16 are provided in order to match the phase of the received waves induced in the heating conductive wire group 2 and transmit them to the lower main antenna wire via the lower auxiliary antenna 13b. It has been experimentally confirmed that the position of the coupling point A is important in improving the directivity characteristics of the antenna at a specific frequency and obtaining substantially circular omnidirectional characteristics in all azimuth angles.

It is preferable that the upper auxiliary antenna wire 13a is also coupled to the main antenna wire 12b by matching the phase, and the output is taken from approximately the midpoint of the auxiliary antenna wire 13a, and this is connected to the main antenna wire 12b as shown in FIG. Connection point B shifted from the center position of the filament 12b
Matching can be performed by supplying
It has been experimentally confirmed that the location of the coupling point B is a major tuning point that has a great influence on improving the directivity of the antenna and obtaining a substantially circular omnidirectional characteristic in all azimuth angles. The upper auxiliary antenna line 13a not only has the function of supplying received power to the main antenna line 12b as described above, but also has the function of supplying received power to the main antenna line 12a, which is located close to about half of one side of the auxiliary antenna line 13a. It is thought that it also has the function of providing induced power.
Therefore, the opposing length of the auxiliary antenna filament 13a and the main antenna filament 12a has a great influence on the directivity characteristics of the antenna. In addition, the main antenna wire 1
It has been experimentally confirmed that an optimal value exists for the horizontal distance from the tip of antenna 2a to the signal extraction point (midpoint) of auxiliary antenna wire 13a.

Preferred dimensions for the antenna pattern of FIG. 1 are as follows.

Distance a, b from the central axis 17 of the window glass 1 to both ends of the auxiliary antenna filament 13a: 300 mm Distance c from the tip of the main antenna filament 12a to the central axis 17: 100 mm From the central axis 17 to the main antenna filament 12c Distance d to upper junction B; 300 mm Distance e, f from central axis 17 to both ends of auxiliary antenna wire 13b; 300 mm Distance g, h from central axis 17 to both ends of coupling element 14; 550 mm Central axis 17 Junction point A on heating conductive wire group 2
Distance i: 100mm The uppermost line of the heating conductive wire group 2 and the coupling element 14
Distance j between coupling element 14 and auxiliary antenna wire 13b; 10 mm Distance k between coupling element 14 and auxiliary antenna wire 13b; 5 mm Auxiliary antenna wire 13b and main antenna wire 12
Gap l between main antenna 12c and main antenna 12b; 20 mm Gap between main antenna 12c and main antenna 12b; 20 mm Gap between main antenna 12b and connection line 15 n; 20
mm Gap o between the connecting wire 15 and the auxiliary antenna wire 13a: 25 mm Gap p between the auxiliary antenna wire 13a and the main antenna 12a: 10 mm The total horizontal length of the main antenna wires 12b and 12c is 1080 mm, respectively. .

The heating conductive wire group 2, the bus bars 4, 5, 6, each antenna wire group 7, and the feeder line 8 are made of conductive paste made of fine silver particles, low-melting glass powder, etc. in an organic solvent, and are applied to the window glass. It is obtained by screen printing on 1 and further baking. The reception output of the glass antenna formed in this way is transmitted to the preamplifier 9 via a coaxial cable 18 connected to the feed point 8.
Here, the signal is divided into an AM wave band and an FM wave band, amplified, and then sent to a tuner.
Antenna installed on the glass surface
Figure 2 shows the average reception sensitivity at all azimuth angles in the domestic FM broadcast wave band from 76MHZ to 90MHZ, and Figure 3 shows the difference between the minimum reception sensitivity at all azimuth angles and the average reception sensitivity at all azimuth angles. Indicated by a solid line. Incidentally, the difference between the average receiving sensitivity, the minimum receiving sensitivity, and the average receiving sensitivity of a conventional antenna provided on the glass surface without the coupling element 14 and the second bent connecting line 16 is shown in FIGS. 2 and 3, respectively. Indicated by a wavy line.

According to this embodiment, as is clear from FIGS. 2 and 3, there is no strong directivity at a specific receiving frequency, and it is possible to obtain an antenna mounted on a glass surface that has no directivity over the entire receiving frequency band. This makes it possible to improve reception sound quality, especially in the FM wave band.

The above shows one embodiment of the present invention,
The invention may be modified within the scope of the claims.
For example, in the present invention, the lengths g and h of the coupling element 14 can be varied within the range of 300 mm to 600 mm, and the distance i from the central axis 17 to the junction point on the group of heating conductive wires 2 is on the left and right sides of the central axis 17. can be varied from 25mm to 400mm. Further, in the present invention, when the antenna is provided on a horizontally long window glass, the feeding point 8 of the antenna is located at a position separated from the side edge of the window glass. , 12b, 12c are adjusted to shorten the lengths, and a feed line 8 independent of the main antenna is provided 25 mm and 30 mm inside from the side edge of the window glass, and a compensation line is provided to connect this to the middle antenna wire 12b. You can also do that.

Although the above description has been made regarding the rear window glass of an automobile, it goes without saying that the present invention can be applied to window glass of vehicles other than automobiles.

[Brief explanation of drawings]

FIG. 1 is a front view and an electric circuit diagram of an antenna provided on the surface of a window glass, showing an embodiment of the present invention;
Figure 2 shows the average receiving sensitivity curve for all azimuth angles at each frequency, and Figure 3 shows the sensitivity change obtained by subtracting the average receiving sensitivity for all azimuth angles from the minimum receiving sensitivity for all azimuth angles for each frequency. It is. 1: Rear window glass, 2: Heating conductive wire group, 7:
Antenna wire group, 12a, 12b, 12c: main antenna wire, 13a, 13b: auxiliary antenna wire, 14: coupling element, 16: second bent connection line.

Claims (1)

[Claims] 1 It has a plurality of heating conductive wires attached horizontally to the surface of the window glass, and a plurality of antenna conductive wires parallel to the heating conductive wires, and one of the antenna conductive wires is parallel to the heating conductive wires. A main antenna consisting of three parallel wires in upper, middle and lower stages connected to each other as if a straight line was bent, and one wire each placed above and below the main antenna. The lower auxiliary antenna line and the lower main antenna line are connected by a connecting line near the vertical center line position of the window glass, and the center line position of the upper auxiliary antenna is connected to the lower main antenna line near the vertical center line position of the window glass. and the middle main antenna wire at a position away from the center line position are connected to each other by a first bent connecting line, and the upper main antenna wire is connected to the upper auxiliary antenna wire by a predetermined length. In the antenna which is extended to the vicinity of the center line in a state of closely facing each other, the antenna is opposed to the auxiliary antenna between the lower auxiliary antenna filament and the uppermost filament of the heating conductive filament. and supply the capacity,
and a second bent connecting line parallel to the auxiliary antenna, one end of which is connected to a position away from the center line position of the uppermost filament, and the other end of the second bent connecting line is connected near the center line position. An antenna provided on a glass surface characterized by providing a coupling element.