JPS609201A - Antenna provided on glass surface - Google Patents

Abstract

PURPOSE:To eliminate the directivity over the entire reception frequency band by using a coupling element which is parallel to an auxiliary antenna having a special connection between the lower auxiliary antenna wire and a heating conduction wire. CONSTITUTION:A heating conduction wire group 2 is provided to the rear window glass 1 of a car, and an antenna wire group 7 is set at the upper part of the group 2. The group 7 contains three parallel main antenna wires 12a-12c, auxiliary antenna wires 13a and 13b connected to those main antenna wires, and a coupling element 14. The wire 13a is provided at the upper stage of the wire 12a, and the middle point between these wires is connected to the position out of the center axis of the wire 12b via a folded connection wire 15. While the antenna 13b is set at the lower side of the wire 12c and connected to the wire 12c at a center shaft 17. The element 14 is set between the wire 13b and the wire at the highest stage of the group 2, and the middle point of the element 14 is connected to the position out of the shaft 17 of the wire at the highest stage of the group 2 via a connection wire 16.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an antenna mounted on a glass surface, and more particularly to an antenna mounted on a glass surface for radio or TV reception in an automobile.

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 such car radio receiving antennas can receive medium waves relatively well, they have the disadvantage that they are directional when it comes to very short waves such as FM broadcasts, making it difficult to receive FM broadcasts depending on the orientation of the car.
In order to reduce the directivity, various antenna patterns are used.

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. They are connected to each other as if they were bent from a single straight line, and
It is equipped with a main antenna consisting of three parallel lines at the middle and bottom, and auxiliary antennas each consisting of one line placed above and below the main antenna. Near the position, the lower auxiliary antenna wire and the lower main antenna wire are connected by a connecting line, and furthermore, the center line position of the upper auxiliary antenna and the middle main antenna wire are separated from the center line position. The glass is connected to the upper main antenna line or the upper auxiliary antenna line by a connecting line that is bent to each other, and the glass extends to the vicinity of the center line while closely facing the upper main antenna line or the upper auxiliary antenna line over a predetermined length. Surface-mounted antennas are known.

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

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 and the lower main antenna wire are connected 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 center line position and the position of the middle main antenna line away from the center line position are connected to each other by a bent connection line, and the upper main antenna line is connected to the upper auxiliary antenna. In an antenna that is extended to near the center line while closely facing the wire over a predetermined length, between the lower auxiliary antenna wire and the uppermost wire of the heating conductive wire. A second bent connecting line is capacitively coupled opposite to the auxiliary antenna, and one end of which is connected to a position away from the center line position of the uppermost filament; This antenna is provided on a glass surface, and is characterized in that a coupling element is provided parallel to the auxiliary antenna, which is connected to the auxiliary antenna.

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

In Fig. 1, a heating conductive wire group 2 for anti-fogging is provided on the rear window glass l of an automobile, and power is supplied from a battery 3 via busbars q and 3.4.

An antenna wire group 7 is provided above these conductive wire groups, and a choke wire with high impedance in the radial im wave number band is provided between the preamplifier, the battery 3, and the ground point from which the received radio waves are fed. I/IO is interpolated. In addition, a decoupling capacitor /l is inserted between the output line of 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 conducting wire group 2 is to disconnect the grounding of the busbar B, connect the busbar L to the busbar 6, flow a heating current from there, and ground the busbar S via the choke coil 10. It can be transformed into.

On the other hand, the antenna wire group 7 includes a main antenna consisting of three mutually parallel antenna wires /, 2a, /2b, /2C, and auxiliary antenna wires 13a, 13b that are in contact with the main antenna.
, and an auxiliary element/lid.

The middle main antenna line /2b extends horizontally from the feeding point, its tip side is bent downward, and is further folded back in parallel to connect to the lower main antenna line /2C. The upper main antenna wire 7.2a extends upward from the feeding point, is further folded back in parallel, and is located approximately in the center of the window glass l.
It's getting close.

The auxiliary antenna line 13a is provided above the main antenna line 12a, and faces the main antenna line 2a closely over a predetermined length.

This auxiliary antenna line 13a is connected to the central axis 17 of the window glass l.
A connecting line/S which is arranged almost symmetrically with respect to the (dot-dash line), whose midpoint is located away from the central axis 17 of the middle main antenna line/2b, parallel to the main antenna line 12b, and whose both ends are bent. connected via. Further, the lower auxiliary antenna /3b is arranged below the lower main antenna line /2C, and is connected to the main antenna line -120 at the central axis 17 of the window glass l.

A coupling element /'7 facing parallel to the lower auxiliary antenna wire 13b is connected between the lower auxiliary antenna wire 13b and the uppermost wire of the heating conductive wire group 2 with respect to the central axis 17 of the window glass l. They are arranged symmetrically, and their midpoints are connected to a position away from the central axis 17 of the uppermost filament of the heating conductive wire group λ via a connecting line L which is parallel to the coupling element llI and whose both ends are bent. ing.

The coupling element lII and the connecting wire /4 are the heating conductive wire group λ
The antenna is provided in order to match the phase of the received wave induced by the antenna and transmit it to the lower main antenna wire via the lower auxiliary antenna 13b, and the position of the coupling point A is determined by the direction of the specific frequency of the antenna. It has been experimentally determined that this is important in improving the characteristics and obtaining nearly circular omnidirectional characteristics in all azimuth angles.

It is preferable that the upper auxiliary antenna line/3a is also coupled to the main antenna line 12b with phase matching.
Matching can be achieved by taking the output from approximately the midpoint of the auxiliary antenna wire 13a and supplying it to a coupling point B shifted from the center position of the main antenna wire 1.2b as shown in FIG.

It has been experimentally determined 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 nearly circular omnidirectional characteristic in all azimuth angles. The upper auxiliary antenna line 13a has the function of supplying received power to the main antenna line/2b as described above, and also serves as a main antenna line located close to about half of one side of the auxiliary antenna line/3&. It is thought that it also has the function of giving induced power to /2a.

Therefore, the auxiliary antenna wire 13a and the main antenna wire /2a
The opposing length of the antenna has a large effect on the directivity characteristics of the antenna. Furthermore, it has been experimentally confirmed that an optimal value exists for the horizontal distance from the tip of the main antenna line/2a to the signal extraction point (midpoint) of the auxiliary antenna line/3PL.

The preferred dimensions of the antenna pattern in Figure 1 are as follows.

Distance a, b from the central axis 17 of the window glass l to both ends of the auxiliary antenna wire 13a: 30 om main antenna wire/
Distance C from the tip of 2a to central axis 17: 100 mm Distance d from central axis 17 to junction B on main antenna line/2C: 300 m Distance from central axis 17 to both ends of auxiliary antenna line 13b e + f ; J 00mm Distance from center axis 17 to both ends of coupling element 1 g + h ; j ! ; Om
m Distance i from central axis 17 to junction A on heating conductive wire group λ; toomm Distance j between the uppermost filament of heating conductive wire group 2 and coupling element/g: 10 mm Coupling element II and auxiliary antenna Gap k with filament/3b
: j mm Auxiliary antenna wire 13b and main antenna wire/2C.

Gap l between main antenna 12c and main antenna 12b; 20 mm Gap m + between main antenna 12c and main antenna 12b
-2 (7 mm Gap n between main antenna 12b and connecting line 1S; 0 mm Gap between connecting line 1S and auxiliary antenna wire/3FL 0
-23mm Gap p between auxiliary antenna wire 13a and main antenna 12a
/Omm Note that the total horizontal length of the main antenna filaments 12b and /2C is toromm.

Heating conductive wire group 21 busbar <z, t, +, each antenna wire group 7. The power supply point is obtained by screen printing a conductive paste made of fine silver particles, low melting point glass powder, etc. in an organic solvent onto the window glass l, and then firing it. The reception output of the glass antenna formed in this way is supplied to the preamplifier via the coaxial cable /g connected to the feed point, where it is divided into AM wave band and FM wave band and amplified. sent to the team. 74MH2~90 of the antenna provided on the glass surface above
Figure 2 shows the average receiving sensitivity in all azimuth angles in the MHz domestic FM broadcast wave band, and Figure 3 shows the difference between the maximum / J% receiving sensitivity in all azimuth angles and the average receiving sensitivity in all azimuth angles. Each is shown by a solid line.

By the way, the difference between the average reception sensitivity, the minimum reception sensitivity, and the average reception sensitivity of a conventional antenna installed on the glass surface without the coupling element/G and the bent connection line/O of the fang 2 are shown in Figure 2 and Fig. 2, respectively. It is shown in FIG. 3 by a broken line.

According to this embodiment, as is clear from FIGS. 2 and 3, strong directivity at a specific receiving frequency is eliminated, and it is possible to obtain an antenna mounted on a glass surface that has no directivity over the entire receiving frequency band. In particular, the received sound quality in the FM wave band can be improved.

The above has shown one embodiment of the present invention, and the present invention can be modified within the scope of the claims.

For example, in the present invention, the lengths g and h of the coupling element /9 can each be varied in the range of 300 mm to l+OQmm, and the distance i from the central axis /7 to the junction point on the heating conductive wire group 2 is the central axis 17. On the left and right sides, zsmm-po.

It can vary within the range of mm. Further, in the present invention, when the antenna is provided on a horizontally long window glass, the position of the feeding point of the antenna is separated from the side edge of the window glass, but in this case, for example, the main antenna line t ,za, 12
b, by adjusting the length of t3c to be short, a feeding point independent of the main antenna is provided 23 mm to 3 Q 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.

It should be noted that although the above description has been made with respect to automobile window glass, it goes without saying that the present invention can be applied to window glass of vehicles other than automobiles.

[Brief explanation of drawings]

FIG. 7 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 in all azimuth angles for each frequency, and Figure 3 shows the sensitivity change obtained by subtracting the average receiving sensitivity in all azimuth angles from the minimum receiving sensitivity in all azimuth angles at each frequency. This is the curve shown. l° Rear window glass, 2: Heating conductive wire group. 7: Antenna line group. /, 2a, /2b, 12C: main antenna filament. /3&, /3b: Auxiliary antenna line. ll: Coupling element, #:: Second bent connecting line Patent applicant: Nippon Sheet Glass Co., Ltd. and one other person Figure 1 Figure 2 Diamond Number of prisoners (MH2) 76 78 80 82 84 EI6 88 Will
Attack position (MH2)

Claims (1)

[Claims] 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 the antenna conductive wire is one. A main antenna consisting of three parallel wires connected to each other like bent straight lines, top, middle, and bottom, 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 in the vicinity of the vertical center line position of the window glass, and the center line of the upper auxiliary antenna The position of the middle main antenna wire is connected to the center line of the middle main antenna wire by a bent connection 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 one end of the uppermost filament is connected to the other end of the bent connecting line of the fang 2 at a position away from the center line position. An antenna provided on a glass surface characterized by providing a coupling element parallel to the auxiliary antenna.