JPH08330833A - Automotive glass antenna - Google Patents

Abstract

PURPOSE: To improve reception sensitivity. CONSTITUTION: An antenna conductor 6 is provided for a window glass plate 1, and the inner conductor 21 of a coaxial cable 20 is connected to a feeding point 4. The outer conductor 22 of the coaxial cable 20 is connected to a car body opening part. In such a case, the outer conductor 22 is connected to the car body opening part at the peripheral part of one side different from the peripheral part of one side in the window glass plate 1 where the feeding point 4 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass antenna for an automobile, which can receive both vertically polarized waves and horizontally polarized waves in a high frequency band such as an FM broadcast frequency band and has a high reception sensitivity.

[0002]

2. Description of the Related Art Conventionally, a conductor pattern produced by, for example, printing a conductive metal-containing paste such as a conductive silver paste on the inside surface of a window glass plate of an automobile and baking it is used for an automobile. Glass antennas are known.

In a conventional glass antenna for an automobile, a feeding point of an antenna conductor is provided on an upper peripheral portion of a window glass plate, and an inner conductor of a coaxial cable connected to a receiver is connected to the feeding point. The outer conductor of the coaxial cable was connected to one side of the vehicle body roof that is in contact with the upper peripheral portion of the window glass plate where the feeding point of the antenna conductor is provided, that is, the vehicle body roof near the upper peripheral portion of the window glass plate. .

The point where the outer conductor of the coaxial cable is connected to the vehicle body is called a ground point. As described above, in the conventional glass antenna for automobiles, the feeding point of the antenna conductor and the earth point are close to each other, and the distance between the feeding point of the antenna conductor and the earth point is usually within about 200 mm.

[0005]

In the above-mentioned prior art, the receiving sensitivity in the high frequency band such as the FM broadcasting frequency band (hereinafter referred to as FM band) and the television broadcasting frequency band (hereinafter referred to as TV band) is low, and the feeding point Since a preamplifier for amplifying the receiving sensitivity must be provided between the receiver and the receiver, there is a problem that productivity is poor.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an antenna having a feeding point provided on a window glass plate of an automobile at a peripheral portion of one side of the window glass plate. In a glass antenna for an automobile, which is provided with a conductor, the inner conductor of the coaxial cable is connected to the feeding point, the outer conductor of the coaxial cable is connected to the opening of the vehicle body, and the received signal induced in the antenna conductor by the coaxial cable is sent to the receiver side. , A glass antenna for an automobile, characterized in that an outer conductor of a coaxial cable is connected to a vehicle body opening portion of a peripheral portion of one side different from a peripheral portion of one side of a window glass plate provided with a feeding point to serve as a ground point. I will provide a.

Further, according to the present invention, an electrically heated defogger having a heater wire and a bus bar for feeding the heater wire is provided on the window glass plate at the rear of the automobile, and a choke coil is inserted between the bus bar and the DC power source for the defogger. Further, there is provided the above glass antenna for a vehicle, wherein the antenna conductor is capacitively coupled to the defogger in close proximity to the defogger at a predetermined interval.

Further, according to the present invention, the first grounding portion is disposed near the window glass plate provided with the feeding point, and the second grounding portion is disposed near the window glass plate near the grounding point. Connect the one earth part and the second earth part with an extension conductor,
The outer conductor of the coaxial cable is connected to the first ground portion, and the second ground portion and the ground point are connected by a conductor wire, whereby the outer conductor of the coaxial cable is connected to the vehicle body opening. The glass antenna for an automobile is provided.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram of a typical example of a glass antenna for an automobile of the present invention. In FIG. 1, 1 is a window glass plate in the rear part of an automobile, 2 is a heater wire, 4 is a feeding point of an antenna conductor, 5a and 5b are bus bars, 6 is an antenna conductor, 9 is a choke coil, 10 is a DC power supply, and 11 is Capacitor, 1
2a and 12b are high frequency coils, 20 is a coaxial cable, 2
Reference numeral 1 is an inner conductor of the coaxial cable 20, 22 is an outer conductor of the coaxial cable 20, 23 is a ground point, 30 is a vehicle body roof, 31 is a right side pillar, 32 is a left side pillar, and 33 is a rear window glass plate 1. It is the car body directly below.

In the present invention, the cable for sending the received signal induced in the antenna conductor 6 to the receiver (not shown) is a coaxial cable 20 having an inner conductor and an outer conductor. It was found that the positional relationship of the earth point 23 is closely related to the reception sensitivity. In the present invention, the vehicle body opening means the vehicle body roof 30 and its vicinity, the right side pillar 31 and its vicinity, the left side pillar 32 and its vicinity, the vehicle body 33 directly below the rear window glass plate 1 and its vicinity, and the trunk. Refers to the lid.

In FIG. 1, a feeding point 4 is a vehicle body roof 3
It is provided on the rear window glass plate 1 near 0, and the earth point 23 is provided on the left side pillar 32 near the rear window glass plate 1. However, the positions where the feeding point 4 and the earth point 23 are provided are not limited to this.

The feeding point 4 may be arranged at any position in the vicinity of the peripheral portion of the rear window glass plate 1, and is not limited to the position shown in FIG.

FIG. 2 is a configuration diagram of the rear window glass plate 1 and its peripheral portion according to the present invention, which illustrates a region where the feeding point 4 and the earth point 23 according to the present invention are arranged. In FIG. 2, A, B, C and D are regions of the rear window glass plate 1, a is a region of the vehicle body roof 30, b is a region of the left side pillar 32, and c is a vehicle body directly below the rear window glass plate 1. 33
, And d is the area of the right side pillar 31. In addition, in FIG. 2, the names of the parts having the same numbers and the same symbols as in FIG. 1 are the same as those in FIG.

The position where the feeding point 4 is arranged will be described with reference to FIG. 2. Areas A, B, C and D of the rear window glass plate 1 will be described.
It may be arranged at any place as long as it is. The areas where the earth points 23 are arranged are areas a, b, c and d.
It may be arranged at any place as long as it is. However, the position where the earthing point 23 is provided needs to be provided at the vehicle body opening on the peripheral portion of one side different from the peripheral portion of the one side of the window glass plate 1 on which the feeding point 4 is provided.

Therefore, for example, if the position where the feeding point 4 is arranged is within the area A, the earth point 23 may be arranged at any position in the areas b, c, d, and the feeding point 4 may be arranged. The earth point 23 may be arranged in any of the areas a, b, and d as long as it is arranged in the area C.

As the mounting means, in FIG. 1, the inner conductor 21 of the coaxial cable 20 is connected to the feeding point 4 provided on the window glass plate 1, and the outer conductor 22 of the coaxial cable 20 is connected.
Was directly connected to the car body opening.

However, the mounting means is not limited to this, and the window glass plate 1 is provided with a first ground portion near the feeding point 4, and the window glass plate 1 is provided with a window near the ground point 23 from the first ground portion. An extension conductor extending to the peripheral edge of the glass plate 1 is provided, and a second ground portion is provided at the tip of the extension conductor. In other words, the first earth portion is arranged near the window glass plate 1 provided with the feeding point 4, and the second earth portion is arranged on the window glass plate 1 near the earth point 23. The ground portion and the second ground portion are connected by an extension conductor.

Further, the inner conductor 21 of the coaxial cable 20 is connected to the feeding point 4, and the outer conductor 22 of the coaxial cable 20 is connected.
May be connected to the first grounding part, and the second grounding part and the grounding point 23 may be connected by a conductor such as a wire or a band.

In FIG. 1, an electrically heated defogger having a heater wire 2 and bus bars 5a and 5b for supplying power to the heater wire 2 is provided on a window glass plate 1 at the rear of an automobile, and a bus bar 5b and a DC power source 10 for the defogger are provided. A choke coil 9 is inserted between them, and a DC current is not transmitted to or received from the defogger on the rear window glass plate 1, but a medium-high frequency current is transmitted or received. The antenna conductor 6 is provided.

In the case of FIG. 1, the antenna conductor 6 is provided in the margin above the defogger of the window glass plate 1 at the rear. The antenna conductor 6 and the defogger are close to each other with a predetermined distance. Due to the proximity, the antenna conductor 6 and the defogger do not send or receive a direct current but send or receive a medium-high frequency current. Are capacitively coupled.

The antenna conductor 6 and the defogger are separated by a distance of, for example, about 0.2 to 30 mm. This capacitive coupling makes the defogger apparently function as a part of the antenna.

In FIG. 1, the choke coil 9 and the high frequency coils 12a and 12b are inserted between the bus bars 5a and 5b and the DC power source 10 for the defogger to increase the impedance of the choke coil 9 and the high frequency coils 12a and 12b in the high frequency band. By doing so, the DC current from the DC power source 10 to the defogger is made to flow, but the current in the high frequency band such as the broadcast frequency band is cut off.

In this way, the choke coil 9 and the high frequency coils 12a and 12b can insulate the heater wire 2 of the defogger and the bus bars 5a and 5b from the ground of the vehicle body in a high frequency manner and are induced in the heater wires 2 and the bus bars 5a and 5b. Further, it is possible to prevent the reception current in the high frequency band such as the radio broadcasting frequency band from flowing to the vehicle body ground, and to send this reception current to the receiver without leakage.

Further, in the case of receiving only the medium wave band, for example, the AM broadcast frequency band, the high frequency coils 12a, 1
2b is usually unnecessary, and only the choke coil 9 is required. If only the FM broadcast frequency band is received, only the high frequency coils 12a and 12b are required. Further, even when both the medium wave band and the FM broadcast frequency band are received, if there is a coil that fulfills the functions of both the choke coil 9 and the high frequency coils 12a and 12b, only such a coil is required.

The antenna conductor 6 and the defogger are
The present invention is applicable regardless of whether capacitive coupling is performed. Therefore, in the case of FIG. 1, the antenna conductor 6
The defogger and the defogger do not have to be close to each other and may not be capacitively coupled. Further, the defogger may not be provided on the rear window glass plate 1.

Regarding the position of the rear window glass plate 1 on which the antenna conductor 6 is provided, FIG. 1 shows an example in which the antenna conductor 6 is provided in the margin above the defogger of the rear window glass plate 1. The position is not limited to the position shown in FIG. 1 and may be a margin below the defogger of the rear window glass plate 1. Further, they may be provided on the upper and lower portions of the defogger respectively, or may be provided on other blank portions.

In other words, in FIG. 1, the antenna conductors may be provided anywhere in the margins above, below, to the left and right of the defogger of the rear window glass plate 1, and the number of antenna conductors provided to the rear window glass plate 1 is limited. Not done.

Further, the antenna conductor provided on the rear window glass plate 1 is not limited to AM and FM radio broadcasting,
It can be applied to TV broadcasting, UHF band, telephone, etc.

In the present invention, the window glass plate provided with the antenna conductor is not limited to the rear window glass plate,
It may be a side window glass plate, a front window glass plate, a roof window glass plate, or the like, and the window glass plate provided with the antenna conductor may not be provided with a defogger.

Further, the antenna conductor 6, the heater wire 2 and the bus bars 5a and 5b are usually formed by printing a conductive metal-containing paste such as a conductive silver paste on the inside surface of the window glass plate and baking it. However, the method is not limited to such a forming method, and a conductive linear body or foil-like body such as a copper wire may be formed on the inside or outside surface of the window glass plate, or inside the window glass plate. May be provided.

Further, in FIG. 1, the shape of the antenna conductor 6 is 1
Although it was a linear pattern of a book, it is not limited to this,
The present invention can be applied to patterns of any shape. The shape of the antenna conductor 6 may be composed of a plurality of linear or curved antenna elements.

Although the antenna conductor shown in FIG. 1 is not provided with an auxiliary antenna conductor, it is not limited to this.
In order to adjust the phase and the directivity, an auxiliary antenna conductor having a substantially T shape, a substantially L shape, a loop or the like is attached to the conductor pattern or the feeding point of the antenna conductor with or without a connection conductor. May be.

[0034]

Although the details of the operation of the present invention are not always clear, it is considered that the current density flowing in the vehicle body is related to the reception sensitivity, and the inner conductor of the coaxial cable is connected to the feeding point of the antenna conductor to When connecting the outer conductor of the cable to the vehicle body opening, the grounding point is provided at the vehicle body opening at the edge of one side different from the edge of the window glass plate where the feeding point is provided. It seems to improve.

[0035]

Embodiments will be described in detail below with reference to the drawings.

(Embodiment 1) FIG. 3 is a block diagram of Embodiment 1.

In FIG. 3, the parts having the same numbers and the same reference numerals as in FIG. 1 have the same names as in FIG. 1, and P ₁ , P ₂ , P ₃ , P
₄ , P ₅ are the positions where the earth points 23 are arranged, e,
Each of f, g, h, i, j, k, and m represents a distance.

In the first embodiment, e = 60 mm and f = 20 m
m, g = 540 mm, h = 50 mm, i = 350 mm,
j = 200 mm, k = 200 mm, m = 50 mm. The size of the feeding point 4 was set to 20 mm × 20 mm.

Positions P ₁ , P ₂ , P ₃ , and P ₄ are positions where the earth point 23 of the first embodiment is arranged. Further, as Comparative Example 1, the position P ₅ was set as the position where the earth point 23 was arranged, and as Comparative Example 2, the feeding point 4 and the position P ₆ were arranged at the positions as shown in FIG. In FIG.
y and z are distances. In Comparative Example 2, the distance y = 50 m
m and the distance z = 20 mm.

In Comparative Example 2 shown in FIG. 4, the antenna conductor 6 and the feeding point 4 have the same dimensions as those in Example 1. Further, in FIG. 4, the names of the parts having the same numbers and the same symbols as in FIG. 1 are the same as those in FIG.

In Tables 1 and 2, the average receiving sensitivities of Example 1 and Comparative Examples 1 and 2 in the frequency band of 76 to 108 MHz are compared. Table 1 is a comparison of average reception sensitivities in vertical polarization, and Table 2 is a comparison of average reception sensitivities in horizontal polarization.

As is clear from Table 1, in Example 1, it can be seen that an improvement of 2 to 12 dBμV is observed as compared with Comparative Examples 1 and 2. Although not shown in particular, the same effect as described above was obtained even when the pattern of the antenna conductor was changed.

(Second Embodiment) FIG. 5 shows a block diagram of the second embodiment. In FIG. 5, P ₇ is the position where the earth point 23 is arranged, n, r, q, t, s, and u are distances, 5 respectively.
Reference numeral 0 is a first ground portion, 51 is an extension conductor, and 52 is a second ground portion. In FIG. 5, the same numbers as those in FIG. 1 and the names of the same reference numerals are the same as those in FIG.

In the second embodiment, the inner conductor of the coaxial cable is connected to the feeding point 4, the outer conductor of the coaxial cable is connected to the first ground portion 50, and the second ground portion 52 and the ground point at P ₇ are connected. And were connected by a conductor wire covered with an insulation coating.

In the second embodiment, the size of each part is s = 2.
0 mm, t = 20 mm, n = 10 mm, u = 540 m
m, r = 10 mm and q = 50 mm.

The average receiving sensitivity in these frequency bands of 76 to 108 MHz was 37.7 dBμV, which was improved by approximately 12 dBμV as compared with Comparative Example 1.

Although not shown in the drawing, the same effect as described above was obtained even when the pattern of the antenna conductor was changed.

Although not shown in particular, the feeding point 4,
The region 50 of the side pillar 32 on the left side is the first ground portion 50.
The same effect was obtained.

[0049]

[Table 1]

[0050]

[Table 2]

[0051]

According to the present invention, the inner conductor of the coaxial cable is connected to the feeding point of the antenna conductor and the outer conductor of the coaxial cable is connected to the opening of the vehicle body in relation to the current density flowing in the vehicle body and the receiving sensitivity. By providing the ground point at the vehicle body opening at the peripheral portion of one side different from the peripheral portion of one side of the window glass plate provided with the feeding point, the receiving sensitivity is remarkably improved.

Further, according to the present invention, regardless of the pattern of the antenna conductor provided on the rear glass of the automobile, both vertically polarized waves and horizontally polarized waves in the high frequency band such as the FM band and the TV band can be obtained. Can be satisfactorily received and the reception sensitivity is high, and it is not necessary to provide a preamplifier for amplifying the reception sensitivity between the feeding point and the receiver, and the productivity is good.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a typical example of a glass antenna for an automobile of the present invention.

FIG. 2 is a configuration diagram of a rear window glass plate 1 and its peripheral portion according to the present invention.

FIG. 3 is a configuration diagram of Example 1 and Comparative Example 1.

FIG. 4 is a configuration diagram of Comparative Example 2.

FIG. 5 is a configuration diagram of a second embodiment.

[Explanation of symbols]

 1: Window glass plate at the rear of the vehicle 2: Heater wire 4: Antenna feeding point 5a, 5b: Bus bar 6: Antenna conductor 9: Choke coil 10: DC power supply 11: Capacitors 12a, 12b: High frequency coil 20: Coaxial cable 21: Inner conductor of coaxial cable 22: Outer conductor of coaxial cable 23: Earth point 30: Vehicle body roof 31: Side pillar on the right side 32: Side pillar on the left side 33: Vehicle body directly under the rear window glass plate 1

Claims (3)

[Claims] 1. An automobile window glass plate is provided with an antenna conductor having a feeding point provided at a peripheral portion of one side of the window glass plate, an inner conductor of a coaxial cable is connected to the feeding point, and an outer conductor of the coaxial cable. Is connected to the opening of the vehicle body and the received signal induced in the antenna conductor by the coaxial cable is sent to the receiver side.In a vehicle glass antenna, the edge of one side different from the edge of one side of the window glass plate provided with the feeding point A glass antenna for an automobile, characterized in that an outer conductor of a coaxial cable is connected to an opening of a vehicle body of the portion to serve as a ground point. 2. An electrically heated defogger having a heater wire and a bus bar for supplying power to the heater wire is provided on a window glass plate at the rear of an automobile, and a choke coil is inserted between the bus bar and the DC power source for the defogger to form an antenna conductor. 2. The glass antenna for an automobile according to claim 1, wherein the glass antenna is capacitively coupled to the defogger in close proximity to the defogger at a predetermined interval. 3. A first grounding portion is provided near the window glass plate provided with a power feeding point, and a second grounding portion is provided near the window glass plate near the grounding point. By connecting the second ground portion and the second ground portion by an extension conductor, connecting the outer conductor of the coaxial cable to the first ground portion, and connecting the second ground portion and the ground point by a conductor wire,
3. The glass antenna for an automobile according to claim 1, wherein the outer conductor of the coaxial cable is connected to the opening of the vehicle body.