JPH0818321A - Glass antenna for vehicle - Google Patents

Abstract

PURPOSE:To improve the transmission/reception gain by deforming a loop antenna and adding filaments which form an inside loop. CONSTITUTION:Heating filaments 2, an antenna 3 where an apex of rectangle formed by filaments 31, 32, 33, and 34 is opened and feed points 41 and 42 are provided at end parts of this opening and a diagonal filament 35 is provided, and another antenna 5 are formed on the inside of a glass plate 1 by screen print and calcination of a conductive paste. After this window glass is set to a rear aperture part, the inner conductor and the outer conductor of a coaxial cable are connected to feed points 41 to 42 respectively. Thus, the loop antenna is deformed and filaments forming the inside loop are added to improve the transmission/reception gain of the antenna. Further, the impedance can be approximated to the characteristic value of the coaxial cable in a wide band, and this antenna is suitable as the mobile telephone or personal radio transmission/reception antenna, and the gain is improved to the practical level.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass antenna provided on a rear window glass of a vehicle such as an automobile, and particularly to a car telephone,
The present invention relates to a glass antenna suitable for transmitting and receiving radio waves in the ultra-high frequency band such as personal radio and commercial radio, and receiving radio waves in the TV broadcast wave UHF band and the like.

[0002]

2. Description of the Related Art Conventionally, as a vehicle antenna for transmitting and receiving an automobile telephone or a personal radio,
Although the pole antenna has been put to practical use, it has a drawback that it has a structure protruding from the vehicle body, which is not only unfavorable for safety and appearance, but also interferes with car washing and may be broken. .

Therefore, in recent years, a glass antenna has been demanded, and JP-A-62-69704 and Shoukai-62-
No. 26912 is proposed. However, in both cases, the transmission / reception gain is considerably lower than that of the pole antenna, so that it has not yet been put to practical use.

The present invention has been made in view of the above points, is suitable as an antenna for a mobile phone or a personal radio that can be put to practical use, and further receives FM radio broadcast waves, TV broadcast waves, and the like. It is also possible to provide a glass antenna for a vehicle that can receive radio waves from GPS satellites when formed into a circular shape.

[0005]

DISCLOSURE OF THE INVENTION The present invention relates to a glass antenna for a vehicle arranged on a window glass of a vehicle, and has a rectangular apex formed by two horizontal filaments and two vertical filaments. Open the part, and open each open end first
Or a second feeding point, which has a line connecting the feeding point formed at the end of the vertical line in the feeding point with a rectangular point, or has an elliptical or circular shape. The opening, and each of the opened ends is a first feeding point,
As a second feeding point, a line connecting one of the feeding points with one point on the outer circumference of an elliptical shape or a circular shape is provided, and an internal conductor of a coaxial cable is provided at the first feeding point, and a second feeding point. And external conductors are connected to each other, and the total length of the outer open loop having a substantially rectangular shape or a substantially elliptical shape is 1.5λα to 1.6λ.
α (λ: center wavelength of transmitted / received radio wave, α: 0.6 in terms of wavelength shortening rate of glass), and the total open loop inside is 1.2λα to 1.4λα (λ: center wavelength of transmitted / received radio wave, α : It is preferable that the wavelength shortening rate of the glass is within the range of 0.6).

[0006]

The antenna of the present invention with the diagonals removed is a kind of loop antenna, but a general loop antenna feeds in the central portion in either a circular or rectangular shape, and therefore a rectangular shape. In the case of, the central portion of the horizontal filament is opened instead of the apex portion and power is supplied from that portion, whereas in the present invention, one apex portion of the rectangle is opened and its end portion is opened. In addition to a whole loop antenna by arranging a line connecting one point of the rectangle with a diagonal line, for example, a loop antenna with a diagonal part, a vertical line and a horizontal line partially opening a triangle To improve the reception gain. The line connecting the feeding point and one point of the rectangle does not have to be a diagonal line.In this case, the line may connect the feeding point and one point on the long side of the rectangle. It becomes a trapezoid instead of a triangle.

In particular, the total length of the outer open loops having a substantially rectangular shape, a substantially elliptical shape or a substantially circular shape is 1.5λα-1.
6λα, and the total open loop inside is 1.
The range of 2λα to 1.4λα is preferable because the reception gain becomes high.

Further, since radio waves for car telephones and personal radio waves are transmitted and received as vertical radio waves, in the case of a loop antenna, both the rectangular shape and the elliptical shape should be formed horizontally as shown in the embodiments described later. TV broadcast wave U preferred
When receiving the HF band or the like, there are both horizontal polarized waves and vertical polarized waves depending on the broadcasting station, so that they may be vertically long.

[0009] Further, if it is formed in a circular shape, the radio waves from the GPS satellites are transmitted as circularly polarized waves and can be received.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings. FIG. 1 is a front view showing a first embodiment in which the glass antenna of the present invention is provided on a rear window glass for an automobile, and FIGS. 2 to 7 are main part details showing an antenna portion of the first to sixth embodiments of the present invention, respectively. FIGS. 8, 8 and 9 are Smith charts showing the impedances of the antennas in Example 1 and Example 2, respectively, in which Mark 1 is 800 MHz and Mark 2 is 8.
50MHz, Mark 3 900MHz, Mark 4 95
Indicates 0 MHz.

Example 1 This is an example in which a single sheet glass is mounted as a rear window glass of a vehicle. As shown in FIGS. 1 and 2, two sheets of glass sheet 1 are provided on the inside of the vehicle together with a heating wire 2 for defrosting. Horizontal stripes 3 ₁ , 3
A rectangular apex portion formed by _two and two vertical filaments 3 ₃ and 3 ₄ is opened, and each of the opened ends is a first feeding point 4 ₁ and a second feeding point 4 _2. The antenna 3 according to the present invention is provided with a diagonal filament 3 ₅ arranged from the first feeding point 4 ₁ formed at the end of the vertical filament in the feeding point.
Together with another antenna 5 are formed by screen printing and firing with a conductive paste.

After mounting such a window glass in the rear opening, an inner conductor and an outer conductor of a coaxial cable (not shown) are connected to the first feeding point 4 ₁ and the second feeding point 4 ₂ , respectively.

The dimensions of each part of the glass antenna for a vehicle thus obtained are A ₁ = 1150 mm, A ₂ = 132
0 mm, B = 760 mm, 3 ₁ , 3 ₂ , 3 ₃ , 3 ₄ , 3
₅ lengths of 105mm, 95mm, 60mm,
60mm, 120mm, ie the total length of the outer rectangular open loop (105mm + 95mm + 60mm
+ 60mm) = 320mm, total length of inner open loop 3 ₂ +3 ₄ +3 ₅ (95mm + 60mm + 120mm)
= 800 MHz to 95 depending on what is set to 275 mm
When the transmission / reception gain in a vertically polarized wave of the 0 MHz North American mobile phone band is measured and the transmission / reception gain of the mobile phone pole antenna is set to 0 dB, the gain difference (hereinafter, abbreviated as the pole antenna ratio) shows an average of − 2.5 dB,
Good results have been obtained that are close to the transmission and reception gains of conventional pole antennas that have been put to practical use.

When the impedance of this antenna was measured, it was as shown in FIG. 8. As is clear from this result, the mark 1 was 800 MHz and the mark 2 was 8 MHz.
50MHz, Mark 3 900MHz, Mark 4 95
It can be seen that the impedance is extremely close to 0 MHz and the characteristic impedance of the coaxial cable during this period, that is, in the vicinity of 50 ohms in the present embodiment, showing extremely good impedance characteristics.

In the present embodiment, since the center frequency of the reception frequency is 875 MHz, λ is about 343 mm, and when α is about 0.6, λα is about 206 mm. Therefore, the total length of the outer open loops is λα. Ratio to 32
0 / 206≈1.55, λ of the total length of the inner open loop
The ratio to α is 275 / 206≈1.33, which is 1.
It is in the range of 5λα to 1.6λα and 1.2λα to 1.4λα.

[0016] EXAMPLE 2 Example 2 shown in FIG. 3 is horizontal strip 3 ₂ wide (width 10m
m) and the auxiliary element 6 having a length of 40 mm is added, and the structure is the same as that of the first embodiment.

With such a glass antenna, 80
When the transmission / reception gain in the vertically polarized wave of the mobile phone band of 0 MHz to 950 MHz is measured and the transmission / reception gain of the mobile phone pole antenna is set to 0 dB, the gain difference (hereinafter, abbreviated as the pole antenna ratio) shows the average. -2.3d
The result was B, which was a good result slightly exceeding that of Example 1.

When the impedance of this antenna was measured, it was as shown in FIG. 9. As is clear from the results, the mark 1 was 800 MHz and the mark 2 was 8 MHz.
50MHz, Mark 3 900MHz, Mark 4 95
It is understood that the characteristic impedance of the coaxial cable, that is, 50 ohms in the present embodiment, is concentrated near 0 MHz, as well as during that time, and exhibits extremely good impedance characteristics as in the case of the first embodiment.

Embodiment 3 to Embodiment 6 In Embodiment 3 shown in FIG. 4, the feeding points 4 ₁ and 4 ₂ and the diagonal line 3 ₅ are arranged on the left and right, and the horizontal filament 3 ₂ is formed wide (5 mm wide). Along with the addition of the auxiliary element 7 having a length of 55 mm and the auxiliary element 8 having a length of 40 mm, the same configuration as that of the first embodiment is obtained. In the fourth embodiment shown in FIG. 5, the element of the present invention is symmetrical. Two sets are provided, the first feeding point 4 ₁ and the second feeding point 4 ₂ are common, and the horizontal filaments 3 ₁ and 3 ₁ ′ are 100 mm, and the horizontal filaments 3 ₂ and 3 ₂ ′.
(Including the feeding point) 100 mm, vertical filaments 3 ₃ and 3 ₃ '60 mm, vertical filaments 3 ₄ and 3 ₄ '65 mm,
Diagonal 3 _5, 3 ₅ 'which was 116mm and Example 5 striated 3 connecting a point of the first feed point and a rectangle as shown in FIG. 6
_The configuration is the same as that of the first embodiment except that ₅ is not a diagonal line and is connected to the first feeding point 4 ₁ and one point on the long side 3 ₁ , and the sixth embodiment shown in FIG. open, either arranged umbilical ₃₅ connecting a point on the feeding point and the elliptical or circular outer circumference, 320 m to the outer circumference length of the elliptical shape
m, the length of the linear 3 ₅ is obtained by a 95 mm, other configurations are obtained by the same structure as in Example 1.

When the transmission / reception gain in the vertically polarized wave of the North American automobile telephone band of 800 MHz to 950 MHz was measured by such a glass antenna for a vehicle, the same result as that of the first embodiment was obtained.

Although the preferred embodiments have been described above, the present invention is not limited to these embodiments, and various applications are possible. As the antenna pattern of the present invention, a rectangle, an ellipse, a circle, or a rectangle whose apex is formed by a curved line can be used, but when transmitting and receiving a mobile phone, a personal radio, etc., the rectangle or the ellipse is used. It is better to form it horizontally. Further, it is better to form a circular shape when receiving radio waves from GPS satellites.

The total length of the outer loop is 1.5λ.
When the total length of the inner loop is in the range of α to 1.6λα and in the range of 1.2λα to 1.4λα, the reception gain becomes high, which is preferable.

Regarding the power feeding, it is preferable to connect the inner conducting wire of the coaxial cable to the first feeding point and the outer conducting wire to the second feeding point as in the embodiment, but conversely the inner conducting wire is connected to the second feeding point. The external conducting wire may be connected to the first feeding point at the feeding point.

Further, the antenna of the present invention may be provided on the front window glass, the side window glass, etc. in addition to the central portion and the upper margin portion of the heating wire lower blank area of the rear window glass. Also,
The gain difference when the transmission / reception gain of the half-wavelength dipole antenna is set to 0 dB by measuring the transmission / reception gain in the vertical polarization of the personal radio whose center frequency is 904 MHz (hereinafter,
It is -2.2 dB, and since the transmission / reception gain of a practically used pole antenna is almost equal to that of a half-wavelength dipole antenna, it is a good antenna close to a pole antenna. Recognize.

Furthermore, T of 470 MHz to 770 MHz
As a result of measuring the reception gains in the horizontal polarization and the vertical polarization of the V broadcast wave UHF band, good results were obtained, and it is possible to receive with this antenna.

The auxiliary element is not necessarily provided, but in order to improve these characteristics, such as when the transmission / reception gain characteristic and the directional characteristic are insufficient depending on the vehicle type,
It may be provided if necessary.

Further, although the glass antenna of the present invention can be used alone, the glass antenna provided on the upper and lower margins of the heating wire of the rear window glass, the glass antenna provided on the front window glass, Further favorable results can be obtained by performing diversity reception in combination with a glass antenna provided on the side window glass or a pole antenna.

When a laminated glass is used as the rear window glass, a fine metal wire such as a copper wire may be embedded in the intermediate film.

[0029]

According to the glass antenna of the present invention, the loop antenna is deformed to add a line forming an inner loop, thereby improving the transmission / reception gain of the antenna and further providing the impedance impedance coaxial cable. It can be approximated to the characteristic value of the bull over a wide band, and is particularly suitable as a transmission / reception antenna for car telephones and personal radios, and improves the gain to a practical level. Furthermore, it is possible to receive TV broadcast wave UHF band and radio waves from GPS satellites.

[Brief description of drawings]

FIG. 1 is a front view showing a first embodiment in which an antenna of the present invention is provided on a rear window glass of an automobile.

FIG. 2 is a detailed view of a main part showing only an antenna part according to the first embodiment of the present invention.

FIG. 3 is a detailed view of a main part showing only an antenna part according to a second embodiment of the present invention.

FIG. 4 is a detailed view of a main part showing only an antenna part according to a third embodiment of the present invention.

FIG. 5 is a detailed view of a main part showing only an antenna part according to a fourth embodiment of the present invention.

FIG. 6 is a detailed view of a main part showing only an antenna part according to a fifth embodiment of the present invention.

FIG. 7 is a detailed view of a main part showing only an antenna part according to a sixth embodiment of the present invention.

FIG. 8 is a Smith chart showing the impedance of the antenna according to the first embodiment of the present invention, in which mark 1 is 800
MHz, Mark 2 is 850MHz, Mark 3 is 900M
Hz, mark 4 indicates 950 MHz.

FIG. 9 is a Smith chart showing the impedance of the antenna according to the second embodiment of the present invention, in which the mark 1 is 800
MHz, Mark 2 is 850MHz, Mark 3 is 900M
Hz, mark 4 indicates 950 MHz.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Flat glass 2 Heating wire for anti-fog 3 Antenna of this invention 4 ₁ 1st feeding point 4 ₂ 2nd feeding point 5 Another antenna 6-8 Auxiliary element

Claims (3)

[Claims] 1. A glass antenna for a vehicle, which is disposed on a window glass of a vehicle, wherein one apex portion of a rectangular shape formed by two horizontal filaments and two vertical filaments is opened, and each is opened. The end of the first feeding point, the second feeding point,
A line connecting the feed point formed at the end of the vertical line among the feed points and one point on the rectangle is provided, and an internal conductor of the coaxial cable is provided at the first feed point, and a second feed point is provided. A glass antenna for a vehicle, characterized in that an external conductor is connected to each. 2. A glass antenna for a vehicle arranged on a window glass of a vehicle, wherein a part of an elliptical shape or a circular shape is opened, and each of the opened ends is a first feeding point and a second feeding point.
And a wire connecting one of the feeding points with one point on the outer circumference of an elliptical shape or a circular shape, and the inner conducting wire of the coaxial cable is provided at the first feeding point and the outside is provided at the second feeding point. A glass antenna for a vehicle, characterized in that conducting wires are connected to each other. 3. The total length of the substantially rectangular, elliptical or circular outer open loop is 1.5λα to 1.6λα.
(Λ: center wavelength of transmitted / received radio waves, α: 0.6 in terms of wavelength shortening rate of glass), and the total of open loops inside is 1.2λα to 1.4λα (λ: center wavelength of transmitted / received radio waves,
3. The glass antenna for vehicle according to claim 1 or 2, wherein α is a glass wavelength shortening ratio of 0.6).