JPH11205023A - Glass antenna system for vehicle use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To satisfactorily receive two different broadcasting bands of high-frequency and low frequency. SOLUTION: First resonance is generated by a first coil 31, which is connected between a first antenna conductor 3a of a window glass board 1 and a receiver 7, and the impedance of the conductor 3a. In addition, a second resonance is generated by a second coil 32 connected between a second antenna conductor 3b and a vehicle body ground and the impedance of the conductor 3b to connect the conductors 3a and 3b through capacitance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a long wave broadcasting band (LW).
Band) (150-280 kHz), medium wave broadcasting band (530-280 kHz)
1630 kHz), short wave broadcasting band (SW band) (2.3-2)
6.1 MHz), FM broadcast band (76-90 MHz (Japan)), FM broadcast band (88-108 MHz (US)),
TV VHF band (90-108 MHz, 170-222
MHz) and TV UHF band (470-770 MHz)
Suitable for receiving, etc., high receiving sensitivity, low noise, and
The present invention relates to a glass antenna device for a vehicle with high productivity.

[0002]

2. Description of the Related Art Conventionally, a glass antenna device for a vehicle shown in FIG. 7 has been proposed as a glass antenna device for a vehicle in which reception sensitivity is improved by utilizing resonance (Japanese Utility Model Publication No. 4-5307).
0). In this conventional example, a defogger 90 composed of a heater wire 2 and bus bars 15a, 15b, 15c is provided on a rear window glass plate 1 of a vehicle, and a bus bar 15a, 15b and a defogger 9 are provided.
By connecting the choke coil 9 to the DC power supply 10 for zero and increasing the impedance of the choke coil 9 in a high-frequency band, a DC current from the DC power supply 10 to the defogger 90 flows, but the The current in the high frequency band is cut off, and the defogger 90 is used as an antenna.

[0003] In the medium wave broadcasting band, defoggers 90
Are parallel-resonated by the coil 71 and the stray capacitance with respect to the ground (hereinafter simply referred to as stray capacitance), and the coil 72, the capacitor 73, and the resistor 74 allow the reception signal of the medium-wave broadcast band to pass. Reference numeral 11 denotes a noise cut capacitor. In the conventional example of FIG. 7, by adopting such a configuration, the receiving sensitivity is improved and the noise is reduced.

However, in this conventional example, the defogger 90
The stray capacitance of the cable connecting the receiver and the receiver is an element that causes parallel resonance, and because the parallel resonance frequency exists in the medium-wave broadcasting band, the S / N ratio is poor, and resonance occurs. Since there was only one, the receiving sensitivity was not sufficient.

[0005] Further, the defogger 90 is connected to the medium wave broadcasting band and the F band.
When the antenna is used for the M broadcast band, the defogger 90
However, even if the shape is optimal for the reception of the medium wave broadcast, there is a problem that the reception sensitivity and the directivity of the FM broadcast are insufficient at the time of the reception of the medium wave broadcast.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks of the prior art, and provides a new glass antenna device for a vehicle having high receiving sensitivity, low noise and good productivity.

[0007]

SUMMARY OF THE INVENTION The present invention provides a first coil, a second coil, and a first coil provided on a window glass plate of a vehicle.
And a second antenna conductor provided on the window glass plate, and causes a first resonance including the impedance of the first antenna conductor and the inductance of the first coil as resonance elements, A second resonance including the impedance of the second antenna conductor and the inductance of the second coil as a resonance element is generated, and the second antenna conductor has a conductor length and a conductor shape for a first reception frequency band. The first antenna conductor has a conductor length and a conductor shape for a second reception frequency band higher than the first reception frequency band, and has a resonance frequency of the first resonance and a resonance frequency of the second resonance. The resonance frequencies are frequencies at which the sensitivity in the first reception frequency band is improved, and the first antenna conductor and the second antenna conductor are electrically connected. To provide a glass antenna device for a vehicle.

In addition, the first antenna conductor and the second antenna conductor are electrically connected by one or more means selected from 1) capacitive coupling due to their proximity, 2) capacitor connection, 3) resistance connection, and 4) coil connection. The glass antenna device for a vehicle, which is electrically connected.

A first coil, a second coil, a first antenna conductor provided on a window glass plate of a vehicle, and a second antenna conductor provided on the window glass plate are provided.
A first resonance including the impedance of the antenna conductor and the inductance of the first coil as a resonance element is generated, and the second resonance including the impedance of the second antenna conductor and the inductance of the second coil as the resonance element. Resonance has occurred, and a received signal in the first received frequency band and a received signal in a second received frequency band higher than the first received frequency band are sent from the first antenna conductor to the receiver. , The resonance frequency of the first resonance and the resonance frequency of the second resonance are frequencies at which the sensitivity in the first reception frequency band is improved, and the resonance frequency between the first antenna conductor and the second antenna conductor. The present invention further provides a glass antenna device for a vehicle, wherein a filter circuit for blocking or attenuating a reception signal in a second reception frequency band is electrically connected.

A first coil is electrically connected between the first antenna conductor and the receiver, and a second coil is electrically connected between the second antenna conductor and the vehicle body ground. The present invention also provides a glass antenna device for a vehicle, which is connected to the glass antenna device.

An electrically heated defogger having a heater wire and a bus bar for supplying power to the heater wire, and an antenna conductor are provided on a rear window glass plate of the vehicle, and are provided between the bus bar and the DC power supply. , Between the bus bar and the vehicle body ground,
Wherein the choke coil is connected to at least one of the first and second coils.
And a first resonance including the impedance of the antenna conductor and the inductance of the first coil as resonance elements, and the first resonance including the impedance of the defogger and the inductance of the second coil as resonance elements. 2 and a received signal in the first received frequency band and a received signal in the second received frequency band higher than the first received frequency band are sent from the antenna conductor to the receiver. , The resonance frequency of the first resonance and the resonance frequency of the second resonance are frequencies at which the sensitivity in the first reception frequency band is improved, and the second reception frequency is provided between the antenna conductor and the defogger. A glass antenna device for a vehicle, wherein a filter circuit for blocking or attenuating a reception signal of a band is electrically connected.

Also, a first antenna is provided between the antenna conductor and the receiver.
And the second coil is electrically connected between the defogger and the vehicle body ground. Also, the second
The glass antenna device for a vehicle described above, wherein a capacitor is electrically connected between the coil and the defogger. Further, the present invention provides the glass antenna device for a vehicle, wherein the first resonance is a series resonance and the second resonance is a parallel resonance. Further, the present invention provides the glass antenna device for a vehicle, wherein the first reception frequency band is a medium-wave broadcast band, and the second reception frequency band is at least one selected from an FM broadcast band, a television VHF band, and a television UHF band. .

[0013]

FIG. 1 shows a rear window glass plate 1 of an automobile.
FIG. 1 is a basic configuration diagram of a glass antenna device for a vehicle of the present invention, using FIG. In FIG. 1, 2 is a heater wire, 3a is a first antenna conductor, 3b is a second antenna conductor, 4a,
4b is a feeding point, 5a and 5b are bus bars, 6 is a resonance circuit, 7
Is a receiver, 21 is a short-circuit line, 31 is a first coil, 32 is a second coil, and 90 is a defogger.

To improve sensitivity, the first antenna conductor 3
a and the second antenna conductor 3b are preferably close to each other and capacitively coupled. The distance between the first antenna conductor 3a and the antenna conductor 3b for capacitive coupling is usually about 0.1 to 50 mm. DC current is not transmitted and received between the capacitively coupled first antenna conductor 3a and second antenna conductor 3b, but high-frequency current of the received signal is transmitted and received.

In FIG. 1, the first antenna conductor 3a and the second antenna conductor 3a
Is not connected to the antenna conductor 3b by a circuit.
However, the first antenna conductor 3a and the second antenna conductor 3b are connected by a circuit, and the first antenna conductor 3a and the second antenna conductor 3b are integrated,
Effective length of the first antenna conductor 3a and the second antenna conductor 3
When both the effective lengths of b are long, the first antenna conductor 3a and the second antenna conductor 3b may or may not be capacitively coupled.

As shown in FIG. 1, when a glass plate 1 of the rear window is provided with an electrically heated defogger 90 having a heater wire 2 and bus bars 5a and 5b for supplying power to the heater wire 2, the second Is preferably capacitively coupled to the defogger 90. The received signal induced by the defogger 90 is transmitted to the second antenna conductor 3b,
This is to improve the receiving sensitivity. Second antenna conductor 3
When b is capacitively coupled to the defogger 90, the reception sensitivity is generally improved by 0.5 dB or more as compared with the case where b is not capacitively coupled.

In FIG. 1, if the second antenna conductor 3b and the defogger 90 are close to each other, they are capacitively coupled. However, the present invention is not limited to this, and at least one of the first antenna conductor 3a and the second antenna conductor 3b may be closely coupled to the defogger 90 for capacitive coupling.
In this case, substantially the same effect as in the case where the second antenna conductor 3b and the defogger 90 are capacitively coupled is obtained.

In FIG. 1, the defogger 90 and the DC power supply 10 are directly connected without providing the choke coil 9 shown in FIG. In such a case, the defogger 90 is not cut off from the vehicle body ground in the broadcast frequency band. If the capacitively coupled capacitance is too large, the first antenna conductor 3a or the second antenna conductor 3b
The received signal induced by the leakage leaks to the vehicle body ground through the defogger 90, and the receiving sensitivity is reduced.

If the capacitively coupled capacitance is too large, engine noise existing in the defogger 90 flows through the first antenna conductor 3a or the second antenna conductor 3b,
The S / N ratio also becomes worse. When the choke coil 9 is not provided, the coupling capacitance between at least one of the first antenna conductor 3a and the second antenna conductor 3b and the defogger 90 is usually preferably 100 pF or less. In the case of 100 pF or less, the reception sensitivity is usually improved by 0.5 dB or more as compared with the case of 100 pF or more.

Similarly, from the viewpoint of the S / N ratio, the coupling capacitance between at least one of the first antenna conductor 3a and the second antenna conductor 3b and the defogger 90 is generally preferably 50 pF or less. In the case of 50 pF or less, the S / N ratio is generally improved by 2.0 dB or more as compared with the case of 50 pF or more.
A more preferred range is 25 pF or less. When it is 25 pF or less, it is usually 3.0 d in comparison with the case where it is more than 25 pF.
The S / N ratio is improved by B or more.

As shown in FIG. 1, portions other than the bus bars of the plurality of heater wires 2 provided on the glass plate 1 of the rear window may be short-circuited by short-circuit wires 21. The short-circuit line 21 for short-circuiting the heater wire 2 at a portion other than the bus bar is provided as necessary, and when the defogger 90 is used as an antenna,
It has a function of stabilizing the impedance of the defogger 90. Further, the short-circuit line 21 also has a function of increasing the band.

FIG. 2 is an equivalent circuit diagram when the first antenna conductor 3a and the second antenna conductor 3b are capacitively coupled in the apparatus of FIG. In FIG. 2, E1 is a voltage power supply of the first antenna conductor 3a, E2 is a voltage power supply of the second antenna conductor 3b, 33 is a floating capacity of the first antenna conductor 3a, and 34 is a floating power of the second antenna conductor 3b. Capacity, 3
5 is a first antenna conductor 3a and a second antenna conductor 3b
Is the proximity capacitance.

The second antenna conductor 3b is preferably used mainly for reception in a first reception frequency band (hereinafter, referred to as a low frequency band) so that suitable reception performance can be obtained in the low frequency band. It is preferable to set the conductor length and the conductor shape. The first antenna conductor 3a has a second reception frequency band higher in frequency than the low frequency band (hereinafter, referred to as high frequency band).
It is preferable to set the conductor length and the conductor shape so as to obtain a suitable reception performance in a high frequency band.

For example, when the high frequency band is an FM broadcasting band, a television VHF band, or a television UHF band, the width of each element constituting the first antenna conductor 3a is:
When the glass shortening ratio K, the wavelength of the highest frequency of the high frequency band lambda _H, the wavelength of the lowest frequency of the high frequency band and lambda _L, the range of _{(λ H / 4) × K~λ} L × K Is preferred. Note that the glass shortening rate K is 0.64.

When the low frequency band is the medium-wave broadcasting band, it is preferable that the conductor length of the second antenna conductor 3b maximizes the usable area and is as long as possible. Second
It is preferable that the antenna conductor 3b is provided on the window glass plate 1 so as to surround most of the first antenna conductor 3a. The second antenna conductor 3 facilitates capacitive coupling between the two.
This is to make the conductor length of b as long as possible.

The first antenna conductor 3a and the second antenna conductor 3b can be used for medium-wave broadcasting, FM broadcasting, short-wave broadcasting, long-wave broadcasting, television VHF, television UHF, and telephone reception. For example, in general, a low frequency band is a medium frequency broadcast band, a high frequency band is an FM broadcast band, and a television V.
One or more of the HF band and the television UHF band.

In the present invention, two resonances occur to improve the receiving sensitivity. Regarding the first resonance, the impedance of the first antenna conductor and the inductance of the first coil are included as resonance elements.

The impedance of the first antenna conductor 3a mainly comprises the stray capacitance 33, and the first antenna conductor 3a
Means the impedance when the first antenna conductor 3a side is viewed from the feeding point 4a. Also, a capacitance component may be connected in parallel between the stray capacitance 33 and the vehicle body ground to adjust the resonance frequency of the first resonance. This capacitance component can also be a resonance element of the first resonance.

The first resonance includes the first coil 31
Stray capacitance of peripheral wiring, stray capacitance of cable connected between glass antenna and receiver, and proximity capacitance 35
And these can also be the resonance elements of the first resonance.

A new circuit element may be provided inside the resonance circuit 6 to perform impedance matching between the first antenna conductor 3a and the receiver. As the first coil 31, a coil of about 10 μH to 1 mH is usually used.

As for the second resonance, the impedance of the second antenna conductor and the inductance of the second coil are included as resonance elements. The impedance of the second antenna conductor 3b mainly includes the stray capacitance 34, and the impedance of the second antenna conductor 3b refers to the impedance when the second antenna conductor 3b side is viewed from the feeding point 4b. Also, a capacitance component may be connected in parallel between the stray capacitance 34 and the vehicle body ground to adjust the resonance frequency of the second resonance. This capacitance component can also be a resonance element of the second resonance.

The second coil 32 usually has a capacity of 10 μH to 1 m.
The one of about H is used. The second resonance includes the stray capacitance and the near capacitance 35 of the wiring around the second coil 32.
Can also be a resonance element of the second resonance. The stray capacitance of the cable connected between the resonance circuit 6 and the receiver is also the second
Affect the resonance of

When the second coil 32 loses its inductance in a high frequency band such as the FM broadcast frequency among the broadcast frequencies (ie, has a capacitive property), the received signal is transmitted to the vehicle body ground. Leakage, reception sensitivity drops. To prevent this, a high-frequency choke coil (not shown) may be connected in series to the second coil 32. Usually, about 0.1 to 100 μH is used for this high frequency choke coil.

When the first antenna conductor 3a and the second antenna conductor 3b are capacitively coupled, the signal received by the second antenna conductor 3b is transmitted to the receiver via the proximity capacitor 35. A new circuit element is provided inside the resonance circuit 6 and the second
Impedance matching between the antenna conductor 3b and the receiver may be performed. In FIG. 1, the first resonance is a series resonance and the second resonance is a parallel resonance. In the present invention,
This is preferable from the viewpoint of improving sensitivity. However, in the present invention, the first resonance is not limited to the series resonance, and the second resonance is not limited to the parallel resonance.

The reason why two resonances occur in the present invention is that only one resonance cannot cover a wide reception frequency band. Therefore, in the present invention, it is desirable to divide the low frequency band into two substantially at the center frequency and to share each of the two resonances with two resonances to achieve flat reception sensitivity. Here, flattening the receiving sensitivity means reducing the difference between the highest receiving sensitivity and the lowest receiving sensitivity within a band such as a low frequency band.

Further, the resonance frequency of the first resonance and the resonance frequency of the second resonance are set to frequencies which improve the sensitivity in the low frequency band. However, if the maximum frequency of the low frequency band was f _H, in the presence of a resonance frequency of the first resonance between the substantially center frequency of 1.5 times the frequency and low frequency bands f _H, and When the lowest frequency of the low frequency band is f _L , the resonance frequency of the second resonance may be present between the frequency 0.6 times f _L and the substantially center frequency of the low frequency band, This is preferable in terms of flattening the receiving sensitivity. Outside of this range, it is difficult to make the difference between the highest reception sensitivity and the lowest reception sensitivity in the low frequency band usually less than about 10 dB, and the flatness of the reception sensitivity in the low frequency band is poor.

It is preferable that the resonance frequency of the first resonance exists in a low frequency band from the viewpoint of improving the receiving sensitivity. When the signal is present in the low frequency band, the reception sensitivity in the entire low frequency band is usually 10 compared to when it is not present.
Improve by about dB.

Therefore, in order to improve both the flatness and the reception sensitivity, the resonance frequency of the first resonance exists between f _H and the substantially center frequency of the low frequency band, and f _L
It is more preferable that the resonance frequency of the second resonance exists between the frequency 0.6 times of the above and the substantially center frequency of the low frequency band.

When the first resonance is a series resonance, the resonance frequency of the first resonance is preferably higher than the substantially center frequency of the low frequency band. When the second resonance is a parallel resonance, the resonance frequency of the second resonance is preferably lower than the substantially center frequency of the low frequency band. When the second resonance is the parallel resonance, the reception sensitivity is significantly reduced in a range lower than the resonance frequency of the parallel resonance.

FIG. 3 is a circuit diagram of a modified example of the resonance circuit 6. In FIG. 3, 41, 44, 50, and 51 are DC cut capacitors, 42 is a bypass capacitor, 43 is a coupling capacitor, 45, 46, 48, and 49 are damping resistors, and 47 is a vehicle such as an engine noise. This is a resistor for reducing noise.

In the resonance circuit shown in FIG. 3, the signal received by the second antenna conductor 3b is transmitted to the receiver via the capacitor 51, the resistor 47 and the capacitor 43. However, when the first antenna conductor 3a and the second antenna conductor 3b are capacitively coupled, the reception signal of the second antenna conductor 3b is transmitted to the receiver even through the proximity capacitance 35. .

The bypass capacitor 42 is provided as necessary, and has a function of transmitting a high frequency band to the receiver. For example, when the low frequency band is the medium-wave broadcast band and the FM broadcast reception is also performed, the FM broadcast band is passed by the bypass capacitor 42.

The capacitor 43 is connected to the first antenna conductor 3a.
This is for strengthening the capacitive coupling between the first antenna conductor 3b and the second antenna conductor 3b, and is provided as needed. The connection between the first antenna conductor 3a and the second antenna conductor 3b is made by the capacitor 43 in the case of FIG. However, they may be connected by another component such as a resistor. In addition, resistors 45, 46, 4
8, 49 are provided as needed. In addition, a capacitor or the like for resonance adjustment may be provided.

The capacitors 41, 44, 50, and 51 are provided as needed, and usually use 100 pF to 50 μF. Normally 1 to 1000 p
F is used. 5 to 500p
F is used. Normally 50Ω for resistors 45, 46 and 49
１００100 kΩ is used.

The stray capacitance of the cable connecting the resonance circuit 6 and the receiver 7 affects the second resonance, causing the S / N ratio to deteriorate due to vehicle noise such as engine noise. Resistance 4
Reference numeral 7 is provided as needed and has a function of preventing the deterioration of the S / N ratio. In particular, it has a function of preventing the deterioration of the S / N ratio in the low frequency band of the medium wave broadcasting band. That is, the resistor 47 has a function of reducing vehicle noise such as engine noise.

The resistance value of the resistor 47 is preferably 10 Ω to 1 kΩ, and more preferably 50 to 500 Ω. When the low frequency band is set to the medium wave broadcasting band, the resistance value of the resistor 47 is set to 10Ω to 1 kΩ.
In this case, the S / N ratio of the medium wave broadcasting band is improved by 1 dB or more as compared with the case where the value is out of the range of 10Ω to 1 kΩ. When the resistance value of the resistor 47 is 50 to 500Ω, 50
S of the medium wave broadcasting band
The / N ratio is improved by 1 dB or more.

As described above, in FIG. 3, the capacitors 41, 42, 43, 44, 50, 51, the resistors 45, 4
6, 47, 48, and 49 are provided as necessary and can be omitted. Here, the omission of the capacitor 42, the resistors 45, 46,
The omission of 49 means that the capacitor 4 is open.
The omission of 1, 43, 44, 50, 51 and the omission of the resistors 47, 48 are short circuits.

FIG. 6 shows a circuit diagram of a different type of resonance circuit from that of FIG. In FIG. 6, reference numeral 52 denotes a high-frequency choke coil. The high-frequency choke coil 52 is provided as needed. The elimination of the high-frequency choke coil 52 is a short circuit.

The high-frequency choke coil 52 separates the first antenna conductor 3a and the second antenna conductor 3b at a high frequency in a normal high frequency band, and changes the effective length of the conductor of the first antenna conductor 3a. And has the function of improving the reception sensitivity in the high frequency band. High frequency choke coil 52
Is usually about 0.1 to 1000 μH.

When the second coil 32 has a low self-resonant frequency in the high frequency band and loses inductance, the received signal in the high frequency band excited by the first antenna conductor 3a is transmitted to the second antenna 32. Since the signal leaks to the vehicle body ground via the coil 32 and the receiving sensitivity drops, the high-frequency choke coil 52 that does not lose inductance in the high-frequency band (that is, does not have a capacitive property) converts the received signal in the high-frequency band into the second signal. Leakage to the vehicle body ground via the coil 32 can be prevented.

In other words, the high-frequency choke coil 52
Has a filter function of passing frequencies in the low frequency band and blocking or attenuating frequencies in the high frequency band. When the high-frequency choke coil 52 is provided, the reception sensitivity in the high frequency band is generally improved by 1 dB or more as compared with the case where the high-frequency choke coil 52 is not provided.

Referring to FIG. 6, in order to prevent the reception signal of the high frequency band excited by the first antenna conductor 3a from leaking to the vehicle body ground, a gap between the first antenna conductor 3a and the second antenna conductor 3b is set. Is connected to a high-frequency choke coil 52. However, the present invention is not limited to this, and what is connected between the first antenna conductor 3a and the second antenna conductor 3b is any filter circuit that blocks or attenuates a received signal in a high frequency band. It may be.

In FIG. 1, when the second antenna conductor 3b and the defogger 90 are slightly capacitively coupled,
The engine noise existing in the defogger 90 flows to the second antenna conductor 3b, and the S / N ratio tends to deteriorate.
In order to prevent this engine noise, it is preferable to connect a noise filter circuit 13 between the bus bar and the DC power supply for the defogger 90 as shown in FIG. When the noise filter circuit 13 is connected, the S / N ratio in the low frequency band is improved by several dB or more as compared with the case where the noise filter circuit 13 is not connected.

FIG. 10 shows a typical example of the noise filter circuit 13.
Shown in The noise filter circuit shown in FIG. 10 includes a capacitor and a coil.
μF and a coil of 0.1 to 10 μH are usually used. Note that the noise filter circuit is not limited to the configuration shown in FIG.

In FIG. 1, the second antenna conductor 3b is not close to the defogger 90, and therefore, the defogger 90 and the second antenna conductor 3b are hardly capacitively coupled or completely capacitively coupled. Absent. Therefore, the defogger 90 is hardly insulated from the vehicle body ground at high frequencies.

However, as described above, the defogger 90 and at least one of the first antenna conductor 3a and the second antenna conductor 3b may be closely coupled to each other in order to improve the reception sensitivity. When completely capacitively coupled, the defogger 90 and the defogger 9 are connected as shown in FIG.
It is preferable that the choke coil 9 be connected between the DC power supply 10 for zero and the defogger 90 to be insulated from the vehicle body ground. When the capacitive coupling is performed in this manner, the reception sensitivity is improved by several dB or more as compared with the case where the capacitive coupling is not performed. The distance between the two for capacitive coupling is usually about 0.1 to 50 mm. The choke coil 9 is usually used at a pressure of about 0.1 to 10 mH.

In FIG. 9, a choke coil 9 is provided between bus bars 5a, 5b and DC power supply 10 for defogger 90.
By inserting the high-frequency choke coils 12a and 12b and increasing the impedance of the choke coil 9 and the high-frequency choke coils 12a and 12b in the broadcast frequency band, the DC current flows from the DC power supply 10 to the defogger 90, but the broadcast frequency band Current is cut off.

In this manner, the defogger 9 is formed by the choke coil 9 and the high-frequency choke coils 12a and 12b.
The heater wire 2 and the bus bars 5a and 5b can be insulated from the vehicle body ground at a high frequency, and the received current in the broadcast frequency band induced by the defogger 90 can be prevented from flowing to the vehicle body ground. Can be sent to receiver.

The high-frequency choke coils 12a and 12b
Among the broadcasting frequency bands, the impedance becomes high in a high frequency band such as the FM broadcasting frequency band, and usually a solenoid or a magnetic core is used. These are FM
It has an inductive inductance in a high frequency band such as a broadcast frequency band and in the vicinity of the frequency band. The choke coil 9 has a low self-resonant frequency in a high frequency band such as an FM broadcast frequency band, and may lose inductance. Therefore, the high-frequency choke coils 12a and 12b substitute for this. The high frequency choke coils 12a and 12b are 0.1
100 μH is usually used.

When the choke coil 9 loses inductance in a high frequency band such as the FM broadcast frequency band, the high-frequency choke coils 12a and 12b are unnecessary. In short, if only a low frequency band such as the AM broadcast frequency band is to be received, the high-frequency choke coils 12a,
2b is usually unnecessary, and only the choke coil 9 is sufficient.
If only a high frequency band such as the FM broadcast frequency band is received, only the high-frequency choke coils 12a and 12b may be used. Even in the case of receiving both the low frequency band and the high frequency band, if there is a coil that satisfies both functions of the choke coil 9 and the high frequency choke coils 12a and 12b, only such a coil may be used.

In FIG. 9, when the first antenna conductor 3a is not capacitively coupled to the defogger 90 and the first antenna conductor 3a and the second antenna conductor 3b are not capacitively coupled, Even if the second antenna conductor 3b and the defogger 90 are capacitively coupled, if the high-frequency choke coil 52 is connected between the first antenna conductor 3a and the second antenna conductor 3b, the high-frequency choke coil 12a, 12b is unnecessary and can be omitted, and the high-frequency choke coils 12a and 12b can be short-circuited.

FIG. 12 is a block diagram of another type of the glass antenna device for a vehicle according to the present invention, which is different from FIG. In FIG. 12, reference numeral 91 denotes a feeding point provided at the tip of the lead wire connected to the defogger 90. In the glass antenna device for a vehicle shown in FIG. 12, the second antenna conductor 3b shown in FIG. Therefore, in the description of FIG. 2, the second antenna conductor 3b will be replaced with the defogger 90, and FIG. 12 will be described.

The resonance circuits shown in FIGS. 3 and 6 are also applied to FIG. However, in the vehicle glass antenna device of FIG. 12, the capacitor 51 has a different importance from the vehicle glass antenna device of the type of FIG. If the capacitor 51 is not provided and the portion of the capacitor 51 is short-circuited, the DC current flowing through the defogger 90 flows into the second coil 32,
The current capacity of the defogger 90 must be increased, and the DC current flowing through the defogger 90 flows into the vehicle body ground via the coil 32, so that the current is wasted. Therefore, it is preferable to provide the capacitor 51.

In FIG. 12, the capacitor 51 is connected to the feeding point 91
And the second coil 32, and the feeding point 9
Since 1 is connected to the bus bar 5b, it is connected between the bus bar 5b and the second coil 32. However, the present invention is not limited to this, and the capacitor 51 may be connected between the bus bar 5a and the second coil 32.
And the second coil 32. In other words, the defogger 9 to which the second coil 32 is connected
The location of 0 is not limited.

Also in FIG. 12, two resonances occur to improve the receiving sensitivity. Regarding the first resonance, the impedance of the first antenna conductor 3a and the first coil 31
Is included as a resonance element. The impedance of the first antenna conductor 3a is mainly the stray capacitance 33
The impedance of the first antenna conductor 3a refers to the impedance when the first antenna conductor 3a side is viewed from the feeding point 4a.

Further, a capacitance component may be connected in parallel between the stray capacitance 33 and the vehicle body ground to adjust the resonance frequency of the first resonance. This capacitance component can also be a resonance element of the first resonance. Further, since the first antenna conductor 3a and the defogger 90 are electrically connected, the first resonance is affected by the impedance of the defogger 90, and can be a resonance element of the first resonance.

The impedance of the defogger 90 mainly consists of the stray capacitance 34, and the impedance of the defogger 90 refers to the impedance when the defogger 90 is viewed from the feeding point 91. Further, the first resonance is affected by the stray capacitance of the wiring around the first coil 31, the stray capacitance of the cable connected between the glass antenna and the receiver, and the proximity capacitance 35. Can be a resonance element.
The first resonance is a series resonance in FIG.

A new circuit element may be provided inside the resonance circuit 6 to perform impedance matching between the first antenna conductor 3a and the receiver. As the first coil 31, a coil of about 10 μH to 1 mH is usually used.

Regarding the second resonance, the second coil 32
And the inductance of the choke coil 9 and the impedance of the defogger 90 are included as resonance elements.

Since the first antenna conductor 3a and the defogger 90 are electrically connected, the second resonance is affected by the impedance of the first antenna conductor 3a.
It can be a resonance element of the second resonance. Further, in the second resonance, the stray capacitance of the wiring around the first antenna conductor 3a,
Stray capacitance of the wiring around the defogger 90, the second coil 3
The stray capacitance and the proximity capacitance 35 of the wiring around 2 also affect and can be a resonance element of the second resonance. The stray capacitance of the cable connected between the output of the resonance circuit 6 and the receiver is also the second.
Affect the resonance of The second resonance in FIG. 12 is a parallel resonance.

Referring to FIG. 12, the case where the inductance of the second coil 32, the inductance of the choke coil 9, and the impedance of the defogger 90 are included as resonance elements will be described. The inductance of the connection circuit and the impedance of the defogger 90 are included as resonance elements. In this case, when the inductance value of the second coil 32 is L ₂ and the inductance value of the choke coil 9 is L _CH , 1.5 · L ₂ ≦ L _CH is preferable, and 2 · L ₂ ≦ L _CH is more preferred.

The reason for this is that the choke coil 9
Has a large current of several tens of amperes (A) flowing through the defogger 90, so the current capacity must be increased.
At the time of mass production, _LCH usually varies about ± 30%. For this reason, the resonance frequency of the second resonance varies, and the sensitivity in the low frequency band varies.
In the device of FIG. 12, since the inductance of the parallel connection circuit of the second coil 32 and the choke coil 9 is the main inductance that causes the second resonance, 1.5 · L ₂
By the ≦ L _CH, and reduce the influence of the second resonance of the inductance of the choke coil 9, it can reduce variations in the resonance frequency of the second resonance. 1.5 · L ₂
≦ L when the _CH is, L _CH can inductance variation of the parallel connection circuit of the second coil 32 and the choke coil 9 may vary ± 30% below 15% ±.

In FIG. 12, the resonance frequency of the first resonance and the resonance frequency of the second resonance are such that the sensitivity in the low frequency band is improved. When the low-frequency band is the medium-wave broadcasting band, the resonance frequency of the parallel resonance is preferably 350 to 530 kHz and 450 to 530 kHz from the viewpoint of improving the S / N ratio.
500 kHz is more preferred.

Further, a capacitance component may be connected in parallel between the stray capacitance 34 and the vehicle body ground to adjust the resonance frequency of the second resonance. This capacitance component can also be a resonance element of the second resonance. The second coil 32 usually has 10 μH to 1 mH.
Some are used.

In FIG. 12, a high-frequency choke coil 52 as an inductance element is provided as necessary.
The high-frequency choke coil 52 is connected to the first antenna conductor 3a.
And the defogger 90 are normally separated in a high frequency band at a high frequency, and have a function of improving the reception sensitivity in the high frequency band without changing the effective length of the conductor of the first antenna conductor 3a.

In the case where the high-frequency choke coil 52 is not provided, the choke coil 9 or the second coil 32 has a low self-resonant frequency in a high frequency band.
When the capacitive property becomes strong, the received signal in the high frequency band excited in the first antenna conductor 3a leaks to the vehicle body ground. Therefore, the high frequency choke coil 52 is provided to prevent this. The high-frequency choke coil 52 in FIG. 12 is generally used at about 0.1 to 1000 μH. By providing the high-frequency choke coil 52, the inductance of the high-frequency choke coil 52 is improved so that the sensitivity in the high frequency band is improved by 0.3 dB or more. It is preferable to set a value.

The low frequency band is a medium frequency broadcasting band, and the high frequency band is an FM broadcasting band, a television VHF band, and a television U.
When the frequency is one or more in the HF band, the high-frequency choke coil 52 normally uses 0.5 to 10 μH. The high-frequency choke coil 52 has 2 d in the range of 0.5 to 10 μH as compared with the case outside the range of 0.5 to 10 μH.
The sensitivity is improved by B or more.

In FIG. 12, the first antenna conductor 3a
A high-frequency choke coil 52 is connected between the first antenna conductor 3a and the defogger 90 in order to prevent the reception signal of the high frequency band excited in the first embodiment from leaking to the vehicle body ground. However, the present invention is not limited to this.
What is connected between a and the defogger 90 may be any filter circuit that blocks or attenuates a received signal in a high frequency band.

In FIG. 12, it is preferable that the first antenna conductor 3a and the defogger 90 are not capacitively coupled. In the case of capacitive coupling, the received signal of the high frequency band excited in the first antenna conductor 3a is
0, it easily leaks to the vehicle body ground via the choke coil 9.

FIG. 13 shows an embodiment in which the glass antenna device for a vehicle shown in FIG. 12 is developed to perform diversity reception. In FIG. 13, 53 is a capacitor, t ₁
Is the first input of the receiver 7, and t ₂ is the second input of the receiver 7. The receiver 7 has a first input t ₁ and a second input t _1
2. Select the stronger of the received signals in the high frequency band between ₂ .

The capacitor 53 is provided as needed.
It has a function of blocking or attenuating a received signal in a low frequency band. The capacitance value of the capacitor 53 is preferably 10 to 150 pF, more preferably 20 to 70 pF. When the low frequency band is the medium wave broadcasting band, the capacitance value of the capacitor 53 is set to 10 to
In the case of 150 pF, the sensitivity of the medium-wave broadcasting band is improved by 1 dB or more, as compared with the case outside the range of 10 to 150 pF. When the capacitance value of the capacitor 53 is set to 20 to 70 pF, compared with the case where the capacitance value is out of the range of 20 to 70 pF,
The sensitivity of the medium wave broadcasting band is improved by 1 dB or more.

In the vehicle glass antenna device shown in FIG.
It is preferable to connect the high-frequency choke coils 12a and 12b between the bus bar and the choke coil 9 as in FIG. Not used in the apparatus of FIG. 12, for using the received signal of the high frequency band excited in the defogger 90 with a second input t _2, the high-frequency choke coils 12a, high frequency excited in the defogger 90 at 12b This is to prevent the reception signal of the band from leaking to the vehicle body ground. FIG.
The resonance circuit 6 of FIG. 3 can also be applied to the glass antenna device for vehicles shown in other figures.

FIG. 14 is a diagram showing a basic configuration in which the glass antenna device for a vehicle according to the present invention is provided on a side window glass plate. The resonance circuit 6 shown in FIGS.

The defogger 90 shown in FIGS. 1, 8, 9, 12, and 13 has a so-called substantially U-shape. However, the defogger 90 according to the present invention is not limited to this, and the defogger 90 shown in FIG. Even a substantially U-shaped defogger 90 can be used in the present invention. The first antenna conductor 3a and the second antenna conductor 3b may be provided anywhere above, below, to the left or to the right of the defogger 90 of the window glass plate 1, and are not limited to the positions shown in FIG. . The number of antenna conductors provided on the window glass plate 1 is not limited as long as it is two or more.

In the present invention, the first antenna conductor 3
The number of antenna conductors provided on the vehicle other than a and the second antenna conductor 3b is not limited. Further, diversity reception may be performed with another antenna device such as the glass antenna device and the pole antenna of the present invention or another glass antenna device.

The feeding points 4a and 4b are shown in FIG.
Is disposed at the right peripheral portion of the window glass plate 1, but is not limited to this, and may be disposed at any position of the window glass plate 1. It may be.

The first antenna conductor 3a and the second antenna conductor 3b shown in FIG. 1 are not provided with an auxiliary antenna conductor. However, for phase adjustment and directivity adjustment,
Auxiliary antenna conductors having a substantially T-shape, a substantially L-shape or the like may be attached to the conductor pattern or the feeding point of these antenna conductors.

Further, in the present invention, the window glass plate on which the first antenna conductor 3a and the second antenna conductor 3b are provided is not limited to the rear window glass plate, but is a side window glass plate, a front window glass plate, and a roof. The defogger 90 may not be provided on the window glass plate provided with the antenna conductor. The defogger 90 shown in FIGS. 12 and 13 has a so-called substantially U-shape, but the defogger according to the present invention is not limited to this, and may be a so-called substantially U-shaped defogger as shown in FIG. Can be used in the present invention.

[0089]

EXAMPLE 1 Example 1 Using a Rear Window Glass Plate of a Car
A glass antenna device as shown in FIG. 1 was manufactured. As the resonance circuit 6, the circuit shown in FIG. Resistors 47, 48,
49, capacitors 50 and 51 were not provided (resistor 4
7, 48, capacitors 50 and 51 are short-circuited, and resistor 49 is open). Each circuit constant is as follows.

The first coil 31 = 220 μH, the second coil 32 = 680 μH, the capacitors 41 and 44 = 2200 pF, the bypass capacitor 42 = 22 pF, the capacitor 43 = 39 pF, the resistance 45 = 10 kΩ, and the resistance 46 = 15 kΩ.

The length and shape of the first antenna conductor 3a were adjusted so that suitable reception performance could be obtained in the FM broadcast band. For the second antenna conductor 3b, the area that can be used as an antenna is maximized and the conductor length is made as long as possible so that the medium wave broadcasting band can be received well.

The distance between the upper or lower part of the first antenna conductor 3a and the second antenna conductor 3b was 10 mm. The distance between the second antenna conductor 3b and the top line of the heater wire 2 was increased to 20 mm. In this case, the second antenna conductor 3b and the defogger 90 were slightly capacitively coupled.

The width of the uppermost element of the first antenna conductor 3a is 730 mm, the width of the central element is 680 mm,
The width of the bottom element (not including the feed point 4a) is 780m
m, distance between top element and center element is 15m
m, distance between center element and bottom element is 15m
m.

The width of each of the four elements of the second antenna conductor 3b (excluding the feed point 4b for the second element from the bottom) is 800 mm, and the distance between the top and bottom elements is 73. 5 mm. First
The line width of each of the antenna conductors 3a and 3b was 0.7 mm.

FIG. 4 is a characteristic diagram of the sensitivity of the medium wave broadcasting band. FIG. 4 compares sensitivity with a pole antenna having a length of 870 mm, and the sensitivity of the pole antenna is 0 dB. F
The sensitivity of the M broadcast band was almost the same as that of a pole antenna having a length of 870 mm (within ± 2 dB). The resonance frequency of the first resonance was 1450 kHz, and the resonance frequency of the second resonance was 600 kHz.

Example 2 (Comparative Example) A conventional vehicle glass antenna device as shown in FIG. 7 was manufactured. The coil 71 is 680 μH, the coil 72 is 100 μH, the capacitor 73
Is 30 pF and the resistor 74 is 5 kΩ. Window glass plate,
As the defogger 90 provided on the window glass plate, the same one as in Example 1 was used.

FIG. 5 is an S / N characteristic diagram at 600 kHz. Radio waves were radiated from a transmitting antenna connected to a signal generator in a shielded room and measured. The horizontal axis of FIG. 5 represents the output voltage of the signal generator, and the vertical axis represents the output voltage of the low-frequency amplifier circuit at the final stage of the receiver in dB. The output of the signal generator was set to 120 dBμV, and the input was sufficiently input to the receiver so that the S / N was saturated (saturated state). At this time, the modulation of the signal generator is 400H.
The modulation frequency of z was adopted and the degree of modulation was 30%. Also,
The state at this time was defined as 0 (zero) dB on the vertical axis as a reference.

In FIG. 5, the solid line is Example 1 and the wavy line is Example 2.
This is the S / N characteristic of FIG. At 50 to 120 dBμV, both the solid line and the wavy line are vertically branched. The line above the branch is a state where modulation is performed (voice signal (S) + noise (N)), and the line below the branch is a state where no modulation is applied to radio waves from the transmitting antenna. Yes (unmodulated state,
Noise (N) only).

As the difference in dB between the upper line and the lower line in FIG. 5 is larger, the S / N ratio is larger, and good reception is possible.
Note that the S / N characteristics in FIG. 5 are irrelevant to vehicle noise such as engine noise and are not affected by the operation or stop of the engine.

Example 3 A glass antenna device as shown in FIG. 1 was manufactured using a rear window glass plate of an automobile.
The resonance circuit 6 employs the circuit shown in FIG.
0, 51, resistors 46, 48, 49 were not provided (resistors 46, 49 were open, resistor 48 was short-circuited, capacitor 50,
51 is short-circuited). For the circuit constant, the first coil 3
1, except for the coil 52 and the resistor 47.
Each circuit constant is as follows. Example 3 with a solid line in FIG.
4 shows the measurement results of the characteristics of the FM broadcast band sensitivity. The first coil 31 = 120 μH, the high frequency choke coil 52 = 2.7 μH, and the resistance 47 = 220Ω.

Example 4 A glass antenna device as shown in FIG. 1 was manufactured in the same manner as in Example 3 except that the high-frequency choke coil 52 was not provided. FIG. 11 shows measurement results of the characteristics of the FM broadcast band sensitivity of Example 4 by broken lines.

Example 5 A glass antenna device as shown in FIG. 9 was manufactured using a rear window glass plate of an automobile.
However, the first antenna conductor 3a, the second antenna conductor 3b, and the defogger 90 used were the same as those in Example 1. As the resonance circuit 6, the circuit shown in FIG. The capacitors 41 and 44 and the resistors 46 and 48 were not provided (the resistor 46 was open, and the capacitors 41 and 44 and the resistor 48 were short-circuited).

A high frequency choke coil of 2.2 μH was connected in series to the second coil 32. The high-frequency choke coils 12a and 12b were not provided. The shortest distance between the second antenna conductor 3b and the defogger 90 was 10 mm, and the coupling capacitance between the second antenna conductor 3b and the defogger 90 was 80 pF. Each circuit constant is as follows.

First coil 31 = 150 μH, second coil 32 = 680 μH, capacitors 50, 51 = 1000 pF, coil 52 = 2.2 μH, resistance 47 = 270Ω, resistance 49 = 10 kΩ, resistance 45 = 15 kΩ, bypass capacitor 42 = 22 pF, choke coil 9 = 1 mH.

The sensitivity of the medium-wave broadcasting band was improved by about 4 dB or more on average from Example 1. Also, the FM broadcast band sensitivity was almost the same as in Example 1.

Example 6 A glass antenna device as shown in FIG. 12 was manufactured using a rear window glass plate of an automobile. Each circuit constant is as follows. First coil 31 = 150 μH, second coil 32 = 560 μH, high-frequency choke coil 52 = 2.2 μH, bypass capacitor 42 = 22 pF, resistance 45 = 15 kΩ, resistance 47 = 270Ω, resistance 48 = 220Ω, capacitors 50, 51 = 1000 pF, choke coil 9 = 1.6 mH, stray capacitance of defogger 90 = 100 pF.

The length and shape of the first antenna conductor 3a were adjusted so as to be able to receive the medium wave broadcast band and the FM broadcast band. The distance between the lower part of the first antenna conductor 3a and the uppermost line of the heater wire 2 was increased to 15 mm. In this case, the first antenna conductor 3a and the defogger 90 were slightly capacitively coupled.

FIG. 15 is a characteristic diagram of the sensitivity in the medium-wave broadcasting band. FIG. 15 compares the sensitivity with a pole antenna having a length of 910 mm, and the sensitivity of the pole antenna is 0 dB. The resonance frequency of the first resonance (series resonance) is 1450
kHz, the resonance frequency of the second resonance (parallel resonance) is 480
kHz. FIG. 16 is a characteristic diagram of the sensitivity of the FM broadcast band.

[0109]

According to the present invention, a first resonance including the impedance of the first antenna conductor and the inductance of the first coil as resonance elements is generated, and the impedance of the second antenna conductor is changed to the inductance of the second coil. Is generated as a resonance element, and the sensitivity is excellent because two resonances are used. Furthermore, the stray capacitance of the cable connected between the glass antenna and the receiver has little effect on the second resonance.
The N ratio is dramatically improved.

In the present invention, the first antenna conductor is designed to be suitable for high frequency band reception even when two different frequency bands of low frequency band and high frequency band are received. By designing the two antenna conductors so as to be suitable for low frequency band reception, it is possible to receive both frequency bands well. Furthermore, since the adjustment for receiving both frequency bands can be performed separately, the adjustment becomes easy, which can contribute to an improvement in productivity.

Since the first resonance and the second resonance can be generated without using the defogger as an antenna, the system does not need the choke coil 9 which is required in the conventional glass antenna. It can also contribute to improving productivity.

Further, when the second antenna conductor is used as a defogger and the combination of the first antenna conductor and the defogger is used as an antenna, when receiving the low frequency band, the first antenna conductor and the defogger are used. Since both of these can be used, the sensitivity in the low frequency band is excellent, and the sensitivity in the high frequency band is excellent because the effective length of only the first antenna conductor can be used when receiving the high frequency band. Further, in this case, when the high frequency band reception signal of the defogger is not used, the high frequency choke coils 12a and 12b can be omitted, and the productivity is improved.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram of a glass antenna device for a vehicle according to the present invention.

FIG. 2 is an equivalent circuit diagram when a first antenna conductor 3a and a second antenna conductor 3b are capacitively coupled in the device of FIG.

FIG. 3 is a circuit diagram of a modification of the resonance circuit 6.

FIG. 4 is a frequency characteristic diagram of sensitivity in Example 1.

FIG. 5 is an S / N characteristic diagram of Example 1 and a conventional example.

FIG. 6 is a circuit diagram of another type of resonance circuit 6 different from FIG. 3;

FIG. 7 is a configuration diagram of a conventional antenna device.

FIG. 8 is a configuration diagram of another type of the glass antenna device for a vehicle according to the present invention, which is different from FIG.

FIG. 9 is a configuration diagram of another type of the glass antenna device for a vehicle according to the present invention, which is different from FIG.

FIG. 10 is a circuit diagram of a noise filter circuit according to the present invention.

FIG. 11 is a characteristic diagram of FM broadcast band sensitivity in Examples 3 and 4.

12 is a configuration diagram of another type of the glass antenna device for a vehicle according to the present invention, which is different from FIG.

FIG. 13 is a configuration diagram of another type of the glass antenna device for a vehicle according to the present invention, which is different from FIG.

FIG. 14 is a configuration diagram when the glass antenna device for a vehicle of the present invention is provided on a side window glass plate.

FIG. 15 is a characteristic diagram of sensitivity in a medium-wave broadcast band of Example 6;

FIG. 16 is a characteristic diagram of sensitivity of the FM broadcast band of Example 6;

[Explanation of symbols]

 1: rear window glass plate of vehicle 2: heater wire 3a: first antenna conductor 3b: second antenna conductor 4a, 4b: feeding point 5a, 5b: bus bar 6: resonance circuit 7: receiver 10: DC power supply 31 : First coil 32: second coil 33: stray capacitance of first antenna conductor 3 a 34: stray capacitance of second antenna conductor 3 b 35: proximity capacitance 41, 44: DC cut capacitor 42: bypass capacitor 43 : Coupling capacitors 45, 46: Damping resistors 47: Resistors 52: High frequency choke coil 90: Defogger E1: Voltage power supply for first antenna conductor 3a E2: Voltage power supply for second antenna conductor 3b

Claims (9)

[Claims] 1. A first antenna comprising a first coil, a second coil, a first antenna conductor provided on a window glass plate of a vehicle, and a second antenna conductor provided on the window glass plate. A first resonance including the impedance of the conductor and the inductance of the first coil as a resonance element is generated, and a second resonance including the impedance of the second antenna conductor and the inductance of the second coil as a resonance element is generated. The second antenna conductor has a conductor length and a conductor shape for a first reception frequency band, and the first antenna conductor has a second reception frequency higher than the first reception frequency band. A conductor length and a conductor shape for the band, wherein the resonance frequency of the first resonance and the resonance frequency of the second resonance are frequencies that improve the sensitivity of the first reception frequency band, respectively. Glass antenna device for a vehicle in which the antenna conductor and the second antenna conductor is characterized in that it is electrically connected. 2. The method according to claim 1, wherein the first and second antenna conductors are electrically connected by one or more means selected from 1) capacitive coupling due to their proximity, 2) capacitor connection, 3) resistance connection, and 4) coil connection. The vehicle glass antenna device according to claim 1, wherein the glass antenna device is electrically connected. 3. A first antenna comprising a first coil, a second coil, a first antenna conductor provided on a window glass plate of a vehicle, and a second antenna conductor provided on the window glass plate. A first resonance including the impedance of the conductor and the inductance of the first coil as a resonance element is generated, and a second resonance including the impedance of the second antenna conductor and the inductance of the second coil as a resonance element is generated. The received signal of the first received frequency band and the received signal of the second received frequency band higher than the first received frequency band are transmitted to the receiver from the first antenna conductor; The resonance frequency of the first resonance and the resonance frequency of the second resonance are frequencies at which the sensitivity in the first reception frequency band is improved, respectively, and the resonance frequency between the first antenna conductor and the second antenna conductor is different. , Glass antenna device for a vehicle filter circuit for blocking or attenuating a received signal of the second reception frequency band, characterized in that it is electrically connected. 4. A first antenna between a first antenna conductor and a receiver.
4. The glass antenna device for a vehicle according to claim 1, wherein the coil is electrically connected, and the second coil is electrically connected between the second antenna conductor and the vehicle body ground. 5. An electric heating type defogger having a heater wire and a bus bar for supplying power to the heater wire, and an antenna conductor provided on a rear window glass plate of the vehicle, between the bus bar and the DC power supply, and A glass antenna device for a vehicle in which a choke coil is connected to at least one of between a bus bar and a vehicle body ground, comprising a first coil and a second coil, wherein the impedance of the antenna conductor and the impedance of the first coil A first resonance including an inductance as a resonance element is generated. A second resonance including an impedance of the defogger and an inductance of the second coil as a resonance element is generated. A received signal and a received signal in a second reception frequency band higher than the first reception frequency band are transmitted from the antenna conductor to the receiver, The resonance frequency of the resonance and the resonance frequency of the second resonance are frequencies at which the sensitivity in the first reception frequency band is improved, respectively. The reception signal in the second reception frequency band is provided between the antenna conductor and the defogger. A glass antenna device for a vehicle, wherein a filter circuit for cutting off or attenuating is electrically connected. 6. A first coil is electrically connected between an antenna conductor and a receiver, and a second coil is electrically connected between a defogger and a vehicle body ground. The glass antenna device for a vehicle as described in the above. 7. The glass antenna device for a vehicle according to claim 5, wherein a capacitor is electrically connected between the second coil and the defogger. 8. The glass antenna device for a vehicle according to claim 1, wherein the first resonance is a series resonance and the second resonance is a parallel resonance. 9. The first reception frequency band is a medium-wave broadcast band,
The second reception frequency band is at least one selected from an FM broadcast band, a television VHF band, and a television UHF band,
6. The glass antenna device for a vehicle according to 2, 3, 4, or 5.