JPH1174714A - High-frequency glass antenna for automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the antenna capable of being installed even when theoretical space of a windowpane is narrow and obtain superior directional characteristics and high sensitivity by specifying the width of an antenna conductor and setting the conductor length of the antenna conductor within a specific range. SOLUTION: This antenna is provided with the antenna conductor 1 installed on the windowpane 2 of an automobile, a feed point 8, and an earth point 9. The antenna conductor 1 is connected to the feed point 8 and for reception, a receive signal between the feed point and earth point 9 is sent to a receiver. For transmission, a transmit signal between the feed point 8 and earth point 9 is applied. The antenna conductor functions for transmission and reception of 500 MHz to 2.0 GHz. The conductor width of the antenna conductor 1 is 1.2 to 5.0 mm. The conductor length of the antenna conductor 1 is within a range of 0.7 λ×K to 1.3 λ×K so as to enable transmission of 500 MHz to 2.0 GHz, where λ is the wavelength of a radio wave and K is the glass contraction rate. Preferably, the length is 0.8 λ×K to 1.3 λK.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a high-frequency glass for an automobile suitable for an automobile communication means using an 800 MHz band (810 to 960 MHz) or a 1.5 GHz band (1.429 to 1.501 GHz) of an automobile telephone. Regarding antennas.

[0002]

2. Description of the Related Art As an antenna for transmission / reception used for an automobile telephone, there is known an antenna for an 800 MHz band having five radially extending conductor strips 53, a feeding point 55 and a ground conductor 54 as shown in FIG. (Japanese Unexamined Patent Publication No.
347910).

[0003]

In this prior art, since the antenna conductor is vertically long, the antenna is provided when the vertical width of the window glass plate of an automobile is short or the defogger is provided substantially at the center of the window glass plate. Is difficult to use when the vertical width of the margin is small.

Further, the antenna conductor shown in FIG. 6 is used so that it can be used even when the space of the vertical window glass plate on which the antenna conductor is provided is small.
When it is provided on a window glass plate after being rotated by a degree, there is a problem that the sensitivity is greatly reduced. Therefore, when the space of the vertical window glass plate on which the antenna conductor of the glass antenna is provided is narrow, the glass antenna shown in FIG. 6 cannot be used.

The present invention has been made in view of the above-mentioned problems of the conventional glass antenna, and has as its object to provide a high-frequency glass antenna for an automobile which can be provided even if a window glass plate on which the antenna is provided has a narrow vertical width. .

[0006]

According to the present invention, an antenna conductor, a feed point and a ground point are provided on a window glass plate of an automobile, the antenna conductor is connected to the feed point, and the feed point and the ground point are used for transmission and reception. In a high-frequency glass antenna for automobiles intended for transmission and reception at 500 MHz to 2.0 GHz, the conductor width of the antenna conductor is 1.2 to 5.0 mm, the wavelength of the transmission radio wave or the reception radio wave is λ, and the glass shortening rate is K. When the conductor length of the antenna conductor is 0.7λ × K ~
Provided is a high-frequency glass antenna for automobiles, which is in a range of 1.3λ × K.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, an automobile high-frequency glass antenna according to the present invention has an antenna conductor 1, a feed point 8 and a ground point 9 provided on a window glass plate 2 of an automobile.
Is provided. The antenna conductors 1 are both connected to a feed point 8 and, in the case of reception, send a received signal between the feed point 8 and the ground point 9 to a receiver (not shown). In the case of transmission, a transmission signal is applied between the feeding point 8 and the ground point 9. This high-frequency glass antenna for automobiles is preferably provided on a rear window glass plate, but may be provided on a side window glass plate, a front window glass plate, a roof window glass plate, or the like.

In FIG. 1, the rear window glass plate 2 is viewed from the rear inside of the vehicle, and the antenna conductor 1 is provided at the lower left of the rear window glass plate 2. Power supply point 8 and ground point 9 in FIG.
Are not the filament of the loop, but the feeding point 8 and the grounding point 9
The portion surrounded by the line indicating is made of a conductor pattern.

The antenna conductor 1 has a frequency of 500 MHz to 2.0 G
It functions for transmission and reception of Hz. The range of the conductor width of the antenna conductor 1 is 1.2 to 5.0 mm. When it is within this range, the sensitivity is higher than when it is outside this range,
Usually, it is improved by 1.0 dB or more. A more preferable range is 1.5 to 3.0 mm. When the thickness is within this range, the sensitivity is usually 0.5 mm as compared with the case outside this range.
Improve by more than dB.

[0010] The conductor length of the antenna conductor 1 is 500 MHz or more.
To make the length suitable for transmission and reception at 2.0 GHz, when the wavelength of the radio wave is λ and the glass shortening rate is K, 0.7λ × K
Λ1.3λ × K. The glass shortening rate K
Is usually 0.64. When it is within this range, the sensitivity is usually 1.0 compared to when it is outside this range.
Improve by more than dB. The preferred range is 0.8λ × K to 1.
The sensitivity is usually improved by 0.5 dB or more when the value is within this range, as compared with the case where the value is outside this range.

It is preferable that the feeding point 8 and the grounding point 9 are capacitively coupled close to each other. If capacitively coupled,
Sensitivity is typically 0.5d compared to the case without capacitive coupling
B or more. Here, the term “capacitive coupling” means that a DC current is not transmitted and received, but an alternating current such as a high-frequency current is transmitted and received. When the distance between the feeding point 8 and the ground point 9 is normally set to about 30 mm or less, capacitive coupling is performed. When the distance between the feeding point 8 and the ground point 9 is 1 to 6 mm, capacitive coupling is more preferable. When it is within this range, the sensitivity is usually 1.0 compared to when it is outside this range.
Improve by more than dB.

The shape of the antenna conductor 1 shown in FIG. 1 is curved on the left side and consists of straight lines and curved lines. However, the present invention is not limited to this, and the shape of the antenna conductor 1 may consist of only a straight line or only a curve.

The phase inversion wire 3, the phase adjustment wire 4, the first ground wire 10 and the second ground wire 11 are provided as necessary. The phase inversion line 3 shown in FIG. 1 has a first side line 3c extending in a substantially vertical direction from the antenna conductor 1, and a predetermined interval substantially parallel to the first side line 3c and near the open end. There is provided a second side stripe 3d extending in a substantially vertical direction from the antenna conductor 1 at a distance. Phase inversion line 3
Also has an outer line 3a connecting the tip of the first side line 3c and the end of the second side line 3d, and the first side line 3c
And an inner line 3b for connecting a portion other than the end of the second side line 3d to a portion other than the end of the second side line 3d. The outer filament 3a and the inner filament 3b are preferably substantially parallel.

The phase inversion wire 3 has an outer wire 3a.
And at least one of the inner wire 3b may be provided.
The shape of the phase inversion wire 3 is not limited to the shape shown in FIG. 1, but may be a shape that forms a semicircle with the first side wire 3c, the outer wire 3a, and the second side wire 3d. You may.

The wire 3 for phase inversion has the function of preventing the current phase of the received signal excited in the antenna conductor 1 from being inverted at half a wavelength, and improving the sensitivity as a directional characteristic. The inner line 3b is for fine adjustment. First side line 3c
Is preferably in the range of 0.4λ × K to 1.0λ × K, the sum L ₃ of the length of the outer filament 3a and the length of the second lateral filament 3d. When it is within this range, the sensitivity is usually improved by 0.5 dB or more as compared with the case outside this range.

The position where the phase inversion wire 3 is provided is defined by a length L when the length from the cross point between the second side wire 3d and the antenna conductor 1 to the open end of the antenna conductor 1 is L.
≧ 1/5 of the conductor length of the antenna conductor 1 is preferable. When it is within this range, the sensitivity is usually improved by 0.5 dB or more as compared with the case outside this range. Note that a plurality of phase inversion wires 3 may be provided on the antenna conductor 1. The sensitivity may be improved by 0.2 dB or more when the inner filament 3b is provided as compared with the case where the inner filament 3b is not provided.

The phase adjusting wire 4 is connected to the feeding point 8 or the feeding point 8.
It is provided on the nearby antenna conductor 1 and has a function of impedance matching between the antenna conductor 1 and the receiver, and a function of improving sensitivity. The length L ₄ of the phase adjusting wire ₄ is preferably 0.25λ × K or less. 0.25λ × K if less than 0.25λ × K
Sensitivity is usually improved by 0.3 dB or more as compared with the case where it is super. A plurality of phase adjusting filaments 4 may be provided. The shape of the phase adjusting wire 4 in FIG. 1 is linear, but is not limited to this. The shape of the phase adjusting wire 4 may be a curved shape, a shape connecting a straight line and a curve, a loop shape, or the like. There may be.

The first ground wire 10 and the second ground wire 11 are both provided at the ground point 9 and have a phase adjusting function. The length L ₁₀ from the end of the ground point 9 to the tip of the first ground wire 10 and the length L 11 from the end of the ground point 9 to the tip of the second ground wire ₁₁ are each 0.1 mm. It is preferably 3λ × K or less. The sensitivity of the antenna conductor 1 is generally improved by 0.2 dB or more when the wavelength is 0.3 λ or less as compared with the case where the wavelength is more than 0.3 λ. In FIG. 1, the first
The ground wire 10 and the second ground wire 11 are both L-shaped, but are not limited to this, and may be linear or curved. When the first ground wire 10 and the second ground wire 11 are provided, the length of the wire can be reduced as compared with the case where only one of them is provided.

FIG. 2 is a block diagram showing a typical example of a high-frequency glass antenna for an automobile of the present invention, which is a different type from that of FIG. FIG.
In FIG. 1, the antenna conductor 1 is provided at the lower right portion of the rear window glass plate 2 when the rear window glass plate 2 is viewed from the rear inside of the vehicle. In FIG. 2, the phase adjustment wire 4 and the antenna conductor 1 are shown.
And form a loop.

When a loop is formed by the phase adjusting wire 4 and the antenna conductor 1, it is effective for impedance matching adjustment with a receiver, and is particularly effective for improving reception characteristics rather than transmission characteristics. is there. In this case, the length L ₄ of the phase adjusting wire 4 (not including the feeding point 8 and the antenna conductor 1) is preferably λ / 4 or less.

FIG. 3 is a plan view of an automobile using the high-frequency glass antenna for automobiles of the present invention. In FIG.
16 is a trunk of a car, 17 is a receiving glass antenna for FM and AM broadcasting, 18 is a defogger, 19 and 20 are areas where the high-frequency glass antenna for a car of the present invention is provided, 2
Reference numeral 1 denotes a telephone transceiver.

A glass antenna shown in FIG. 1 or FIG. 2 is provided in the installation area 19 and the installation area 20. This is for performing diversity reception. Although the length of the cable connecting the antenna conductor 1 and the telephone transceiver 21 is minimized to prevent cable loss, the telephone transceiver 21 is provided at a substantially central portion in the trunk 16 in FIG. However, the present invention is not limited to this. The dotted line in FIG.
1 shows the telephone transceiver 21 and the cable.

In FIG. 8 showing an application example, 21 is a feeding point, 22 is a bus bar of the defogger 18, 23 is a television receiving antenna conductor, 24 is a heater wire of the defogger 18, 2
Reference numeral 6 denotes a capacitive coupling conductor provided on the television receiving antenna conductor 23, and reference numeral 27 denotes a first branch branched from the capacitive coupling conductor 26.
Is a second capacitive coupling element branched from the capacitive coupling conductor 26.

It is preferable that the antenna length of the television receiving antenna conductor 23 be adjusted for UHF reception or VHF-Hi reception. When the television receiving antenna conductor 23 is capacitively coupled to the heater wire 24, the television receiving antenna conductor 23 also functions for VHF-Low reception.

The feeding point 21 of the television receiving antenna conductor 23 is provided substantially above the ground point 9 provided on the rear window glass plate 2. A television receiving antenna conductor 23 is provided to extend in a substantially horizontal direction from the feeding point 21.
A capacitive coupling conductor 26 is provided on the television receiving antenna conductor 23 substantially above the phase inversion wire 3. The feed point 21 is a feed point of the television receiving antenna conductor 23 which is an antenna element other than the antenna conductor 1.

At the tip of the capacitive coupling conductor 26, a first capacitive coupling element 27 and a second capacitive coupling element 28 are provided. The first capacitive coupling element 27 and the outer line 3a are close to each other at a predetermined distance, and the second capacitive coupling element 28 and the second side line 3d are close to each other at a predetermined distance. As a result, the first capacitive coupling element 27, the second capacitive coupling element 28, and the phase inversion wire 3 are capacitively coupled. By the capacitive coupling, the high-frequency current of the received radio wave excited in the television receiving antenna conductor 23 is guided to the phase inversion wire 3 and the receiving sensitivity is improved. It is preferable that both the first capacitive coupling element 27 and the second capacitive coupling element 28 are provided in the capacitive coupling conductor 26, but either one may be provided.

The distance between the first capacitive coupling element 27 and the outer filament 3a or the second capacitive coupling element 2
8 and the second side line 3d are 1.0 to 2
It is preferably in the range of 0.0 mm. When it is within this range, the sensitivity is usually improved by 1.0 dB or more as compared with the case outside this range.

The sum of the conductor length of the first capacitive coupling element 27 and the conductor length of the second capacitive coupling element 28 is preferably in the range of 0.1λ × K to 1.0λ × K. When it is within this range, the sensitivity is usually improved by 0.5 dB or more as compared with the case outside this range. More preferred is a range of 0.3λ × K to 0.7λ × K,
When it is within this range, the sensitivity is usually improved by 1.0 dB or more as compared with the case outside this range.

[0029]

【Example】

(Example 1) The glass antenna of FIG. 1 was provided in the disposition area 20 shown in FIG. 3, and the glass antenna of FIG. Diversity reception was performed so that the stronger of the received signals from both glass antennas was used. The glass antenna of FIG. 1 was used for transmission and reception, and the glass antenna of FIG. 2 was used only for reception.

Table 1 shows dimensions (unit: m) of each part of the glass antenna of FIG. 1 (column A) and the glass antenna of FIG. 2 (column B).
m). In the glass antenna of FIG. 2, the distance between the antenna conductor 1 and the phase adjusting wire 4 in the substantially horizontal direction is 2 m.
m.

[0031]

[Table 1]

FIG. 4 shows the result of diversity reception.
(Reception frequency-sensitivity characteristic) and FIG.
Directivity at MHz). In FIG. 4, the solid line indicates the sensitivity of the pole antenna having a length of 880 mm, and the dotted line indicates the sensitivity characteristic of the diversity reception according to the present embodiment. In FIG.
The solid line is the directivity of the glass antenna of FIG. 1 and the dotted line is the directivity of the glass antenna of FIG. 2, where 0 ° is the front direction of the vehicle and 90 ° is the right direction as viewed from the vehicle side.

Example 2 An automobile high-frequency glass antenna as shown in FIG. 8 was manufactured using the rear window glass plate 2 of the automobile. Column C of Table 1 shows the dimensions (unit: mm) of each part. The dimensions of the other parts were as follows. FIG. 7 shows reception frequency-sensitivity characteristics of the present example and a 450 mm long pole antenna.

The shortest distance between the first ground wire 10 and the television receiving antenna conductor 23 = 7 mm, the conductor length of the television receiving antenna conductor 23 = 500 mm, the conductor length of the capacitive coupling conductor 26 = 30 mm, The distance between the capacitive coupling element 27 and the outer filament 3a = 5 mm, the distance between the second capacitive coupling element 28 and the second lateral filament 3d = 5 mm, the length of the first capacitive coupling element 27 = 37 mm Length of the second capacitive coupling element 28 = 30 mm.

Example 3 Same as Example 2 except that the feeding point 21, the television receiving antenna conductor 23, the capacitive coupling conductor 26, the first capacitive coupling element 27, and the second capacitive coupling element 28 are not provided. A high frequency glass antenna for automobiles with specifications was manufactured. FIG. 7 shows a reception frequency-sensitivity characteristic of this example.

[0036]

According to the present invention, the glass antenna can be provided even when the space of the vertical window glass plate on which the antenna conductor of the glass antenna is provided is narrow, and excellent directional characteristics and high sensitivity can be obtained. Further, by providing antenna conductors on the lower left and right sides of the rear window glass plate of the automobile and performing diversity reception, omnidirectionality can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a typical example of a high-frequency glass antenna for a vehicle according to the present invention.

FIG. 2 is a configuration diagram of a typical example of a high-frequency glass antenna for an automobile according to the present invention of a different type from FIG.

FIG. 3 is a plan view of an automobile using the high-frequency glass antenna for automobiles of the present invention.

FIG. 4 is a diagram showing a reception frequency-sensitivity characteristic of Example 1.

FIG. 5 is a directional characteristic diagram of Example 1 at a reception frequency of 840 MHz.

FIG. 6 is a configuration diagram of a conventional example.

FIG. 7 is a graph showing reception frequency-sensitivity characteristics of Examples 2 and 3.

FIG. 8 is a configuration diagram of an application example.

[Explanation of symbols]

 1: Antenna conductor 2: Rear window glass plate 3: Phase inversion wire 3a: Outer wire 3b: Inner wire 4: Phase adjustment wire 8: Feeding point 9: Ground point 10: First ground wire 11: Second ground wire 18: Defogger 21: Feeding point of television receiving antenna 22: Bus bar 23: Television receiving antenna conductor 24: Heater wire 26: Capacitive coupling conductor 27: First capacitive coupling element 28 : Second capacitive coupling element

Claims (2)

[Claims] An antenna conductor, a feed point and a ground point are provided on a window glass plate of an automobile. The antenna conductor is connected to the feed point, and the feed point and the ground point are used for transmission and reception.
In a high-frequency glass antenna for automobiles for transmitting and receiving signals of MHz to 2.0 GHz, the conductor width of the antenna conductor is 1.2 to 5.0 mm, the wavelength of the transmission radio wave or the reception radio wave is λ, and the glass shortening rate is K. When the conductor length of the antenna conductor is 0.7λ × K〜1.
A high-frequency glass antenna for an automobile, wherein the antenna has a range of 3λ × K. 2. The high frequency glass antenna for an automobile according to claim 1, wherein the antenna conductor is capacitively coupled to an antenna element other than the antenna conductor.