JPH1079615A - On-vehicle glass antenna system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reception sensitivity by omitting a choke coil. SOLUTION: A window glass plate is provided with a low reception frequency band use antenna conductor 1 and a high reception frequency band use antenna conductor 2. A 1st oil 3 has a low impedance at a low reception frequency band and the 1st coil 3 and mainly a stray capacitance of the high reception frequency band use antenna conductor 2 cause 1st resonance and a 2nd coil 8 and a stray capacitance of the low reception frequency band use antenna conductor 1 cause apparently 2nd resonance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass antenna device for a vehicle, which is suitable for a receiving device for an automobile and is used for receiving radio, television, telephone, satellite communication and the like.

[0002]

2. Description of the Related Art As shown in FIG. 28, an electric heating type defogger 33 having a heater wire 32 and a bus bar for supplying power to the heater wire 32 in a rear window glass plate 31 of an automobile, And an antenna conductor 136 which is closely coupled and capacitively coupled so that high-frequency current is transmitted and received, and the bus bar and the defogger 33 are not provided.
A glass antenna device (conventional example 1) in which a choke coil 139 is connected between direct current power supplies 10 is known.

In Conventional Example 1, a bus bar and a DC power supply 1
By inserting the choke coil 139 between 0 and increasing the impedance of the choke coil 139 in a high frequency band such as a broadcast frequency band, a DC current flows from the DC power supply 10 to the defogger 33 but a current in the broadcast frequency band is cut off. I am trying to do it.

In this manner, the defogger 33 can be insulated from the vehicle body ground (ground) at a high frequency by the choke coil 139, and the high-frequency reception current induced by the defogger 33 can be prevented from flowing to the vehicle body ground. Can be sent to the receiver 20 without omission.

Further, in the prior art (not shown) other than that shown in FIG. 28, an AM broadcast frequency band (hereinafter, referred to as an AM broadcast band) is provided on a window glass plate of an automobile in order to improve reception sensitivity.
Antenna device (conventional example 2) in which an antenna conductor for the FM broadcast frequency band (hereinafter referred to as the FM broadcast band) is separately provided, the area occupied by the antenna conductor is large, and the field of view is deteriorated. And so on.

[0006]

In the first conventional example, a large DC current of several tens of amperes for the defogger 33 flows through the choke coil 139. Therefore, in order to cut off the high-frequency current, a reduction in inductance due to magnetic saturation occurs. It is necessary to prevent this, and it is usually necessary to adopt a special winding structure.

Also, the inductance of the choke coil 139 is usually as large as 0.6 to 1 mH, and it is necessary to reduce the DC resistance in order to suppress the power loss. Must be used.

As described above, when the defogger 33 is used as an antenna in order to secure good reception sensitivity, a structurally large, large and heavy choke coil and an FM
It is necessary to take measures to reduce the reception sensitivity in the broadcasting band, and the entire glass antenna device is structurally complicated, and there is a problem that productivity is poor.

Further, in the conventional example 2, since the antenna conductor for the AM broadcast band and the antenna conductor for the FM broadcast band are not used at the time of receiving the AM broadcast, the receiving efficiency is poor. Therefore, it has been desired to develop a glass antenna device capable of improving reception sensitivity by using both antenna conductors and receiving efficiently.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has an antenna conductor for a low reception frequency band and an antenna conductor for a high reception frequency band on a window glass plate of a vehicle. The first coil is electrically connected between the antenna conductor for the low reception frequency band and the antenna conductor for the high reception frequency band, and the inductance value of the first coil is the input impedance of the receiver side in the low reception frequency band. Of 5
Less than twice, electrically connect the antenna conductor for the high reception frequency band and the receiver with a cable, and send the signal of the antenna conductor for the high reception frequency band to the receiver,
The first coil and the capacitance including the sum of the stray capacitance of the antenna conductor for the high reception frequency band and the stray capacitance of the cable cause the first resonance to occur, so that the resonance frequency of the first resonance is high. So that it exists at a lower frequency than the frequency band,
A second coil is electrically connected between the antenna conductor for the low reception frequency band or the antenna conductor for the high reception frequency band and the vehicle body ground, and a stray capacitance between the second coil and the antenna conductor for the low reception frequency band. A glass antenna device for a vehicle, characterized in that a second resonance is apparently caused by a capacitance including the following.

The present invention also provides a dual-purpose antenna conductor for a low reception frequency band and a high reception frequency band on a window glass plate of a vehicle, wherein a first coil and a capacitor are provided between the dual-purpose antenna conductor and the receiver. Are electrically connected in parallel with each other so that the inductance value of the first coil has a low impedance at least in a low reception frequency band, and the capacitor has a low impedance in a high reception frequency band. The capacitance value is such that the impedance becomes high in the reception frequency band. The capacitance value includes the sum of the stray capacitances of the first coil, the first coil, the antenna conductor for the high reception frequency band, and the stray capacitance of the cable. The first resonance is caused to occur, the resonance frequency of the first resonance is present at a frequency lower than the high reception frequency band, and the dual-purpose capacitor of the capacitor is used. To provide a glass antenna device for a vehicle, characterized by electrically connecting the antenna conductor side with the end on the opposite side and the receiver by a cable.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a circuit diagram of a basic configuration of the present invention for explaining the principle of the present invention. In FIG. 1, reference numeral 1 denotes an antenna conductor for a low reception frequency band (hereinafter, referred to as a low band antenna conductor), 2 denotes an antenna conductor for a high reception frequency band (hereinafter, referred to as a high band antenna conductor), and 3 denotes a first coil. ,
Reference numeral 8 denotes a second coil provided as needed, and reference numeral 18 denotes a third coil provided as needed. In the drawings other than FIG. 1, the names of the same numbers and the same reference numerals as those of FIG. 1 are the same as those of FIG. 1.

FIG. 2 shows an equivalent circuit diagram of FIG. In FIG. 2, E _L is the voltage power supply of the low band antenna conductor 1, E _H is the voltage power supply of the high band antenna conductor 2, C _L0 is the effective capacity of the low band antenna conductor 1, and C _L1 is the low band antenna conductor. The stray capacitance (ineffective capacitance) of the conductor 1, C _H0 is the effective capacitance of the high band antenna conductor 2, and C _H1 is the capacitance of the sum of the stray capacitance of the high band antenna conductor 2 and the stray capacitance of a cable (not shown) ( Invalid capacity).

Here, the cable refers to a cable connecting the high band antenna conductor 2 and a receiver (not shown). In addition, the floating capacity means electric capacity. In the drawings other than FIG. 2, the names of the same numbers and the same reference numerals as those of FIG. 2 are the same as those of FIG. 2.

Usually, the effective capacity C _L0 is _1/1 / the ineffective capacity C _L1 .
It is about 5 to 1/10. Further, since the effective capacitance C _H0 is about 1/10 of the stray capacitance C _H1 , the influence on the reception in the low reception frequency band is small, and when the low reception frequency band is received, the effective capacitance C _H0 in FIG. It is also possible to consider an electrical phenomenon related to only frequency characteristics such as resonance assuming that both ends of the effective capacitance C _H0 are opened and the voltage power source E _{H of the} high band antenna conductor 2 is not connected, omitting _H0 .

In the present invention, when receiving a low reception frequency band, the first coil 3 has a low impedance, so that the low band antenna conductor 1 and the high band antenna conductor 2 are connected. As a result, the high band antenna conductor 2 also functions as a part of the low band antenna conductor 1. This is because the reception sensitivity in the low reception frequency band is improved by the sum of the effective lengths of the antenna conductors for the low band antenna conductor 1 and the high band antenna conductor 2.

[0017] The connection in the present invention means to be electrically connected. Thus, although not shown in FIG.
Circuit elements other than the first coil 3 (for example, a bypass capacitor or a resistor) may be connected between the low band antenna conductor 1 and the high band antenna conductor 2. In the following description, the meaning of the connection is the same.

For example, when the low reception frequency band is the AM broadcast band and the high reception frequency band is the FM broadcast band, the high band antenna conductor 2 also functions as a part of the low band antenna conductor 1 and Since the effective length of the band antenna conductor 1 becomes longer,
A lot of received radio waves in the AM broadcasting band can be received, and the receiving sensitivity in the AM broadcasting band is improved.

Therefore, the sum of the effective lengths of the low-band antenna conductor 1 and the high-band antenna conductor 2 is
A length suitable for low reception frequency band reception is desirable. Usually, the first coil 3 is used at about 1 μH to 1 mH.

Further, another element may be used in place of the first coil 3 as long as the element has a function as an inductance component. In addition, if the component has high impedance in a wide frequency band from a frequency higher than the low reception frequency band to a high reception frequency band, it is used even if it is a circuit element including an inductance component and including at least one of a capacitor and a resistance component. it can.

It is preferable that the first coil 3 has a high impedance in a high reception frequency band for high reception frequency band reception. However, in the high reception frequency band, the first coil 3 can be used even if it does not have high impedance.

The low impedance means that the low band antenna conductor 1 and the high band antenna conductor 2 are connected, and the reception signal of the low reception frequency band of the low band antenna conductor 1 is transmitted to the high band antenna conductor 2. It refers to the impedance within the easy-to-flow range and usually refers to 5 times or less the input impedance of the receiver. The input impedance on the receiver side usually means the input impedance of the receiver. However, when an impedance converter is connected between the input of the receiver and the antenna, it refers to the input impedance of the impedance converter.

The high impedance means that the low band antenna conductor 1 and the high band antenna conductor 2 are not connected.
It refers to an impedance within a range in which a reception signal of the low reception frequency band of the low band antenna conductor 1 does not easily flow to the high band antenna conductor 2, and usually means more than five times the input impedance of the receiver.

When the low reception frequency band is AM broadcasting, A
The input impedance of the receiver at the time of receiving the M broadcast is usually 1 to 10 kΩ. Therefore, for example, when the input impedance on the receiver side is 5 kΩ, 25 kΩ
Ω or less has low impedance, and more than 25 kΩ has high impedance.

When the high reception frequency band is FM broadcast, the input impedance of the receiver at the time of FM broadcast reception is usually 50 or 75Ω. So, for example,
If the input impedance on the receiver side is 50Ω, 250Ω or less becomes low impedance and 250Ω
Super becomes high impedance.

In addition, because of the above-described operation, in the case of reception in the low reception frequency band, the reception signal of the antenna conductor 1 is transmitted to the first coil 3, and
The received signals of the antenna conductor 1 are transmitted to the receiver.

In this case, series resonance (first resonance) is caused by the inductance of the first coil 3 and mainly the reactive capacitance C _H1 . In short, the first resonance is caused between the first coil 3 and the first other element. Here, the first other element is not limited to only the reactive capacitance C _H1, but includes an inductance component, a capacitance component, a resistance component, and the like which are artificially or non-artificially added to the circuit of FIG.

Due to the first resonance which is the series resonance, the reactance (series resonance reactance) of the first coil 3 and the reactive capacitance C _H1 connected in series and the reactive capacitance C _L1 cause the low-band antenna conductor 1 side. When viewed from above, parallel resonance occurs.

By this parallel resonance, the receiving sensitivity in a desired receiving frequency band can be improved. For the first resonance, it is necessary that the resonance frequency exists at a frequency lower than the high reception frequency band. In the case where the first resonance is caused, the reception sensitivity in the entire low reception frequency band is usually smaller than the case where the first resonance is not caused.
It is improved by about 5 dB or more.

The resonance frequency of this parallel resonance preferably exists in a low reception frequency band. When it is present, the reception sensitivity in the entire low reception frequency band is lower than when it does not exist,
Usually, it is improved by about 10 dB or more.

In the above description, the first resonance is preferably a series resonance in FIGS. But,
The first resonance is not limited to the series resonance, and the first resonance may be a parallel resonance by connecting at least one selected from a coil, a capacitor, and a resistor to a predetermined portion of the circuit in FIGS. This can be applied to the circuits shown in FIGS.

This series resonance is slightly affected by the stray capacitance of the wiring around the low band antenna conductor 1 and the high band antenna conductor 2. For example, it is the stray capacitance of wiring such as the first coil 3 and the second coil 8.

In the present invention, the low-band antenna conductor 1 has the reactive capacitance C _L1 , and the apparent parallel resonance (second resonance) is mainly caused by the inductance of the second coil 8 and the reactive capacitance C _L1. Preferably.

In short, the second resonance is caused by the second coil 8 and the second other element. Here, the second other element is not limited to only the ineffective capacitance C _L1, but includes an inductance component, a capacitance component, a resistance component, and the like that are artificially or non-artificially added to the circuit of FIG. 1.

In order to cause the second resonance, the second resonance
Even if the inductance value of the coil 8 and the value of the second other element are set, the second resonance (hereinafter, apparently the second resonance) does not actually occur, and is shown in FIG. In the system of the entire circuit, two resonances different from the second resonance (accompanying resonances of the second resonance) occur. When viewed from the low-band antenna conductor 1, the accompanying resonance has a strong parallel resonance property.

By these two resonances, the receiving sensitivity in a desired receiving frequency band can be improved and the receiving sensitivity can be flattened. When the incidental resonance of the second resonance is caused to occur, the receiving sensitivity in the entire low receiving frequency band is improved by about 5 dB or more as compared with the case where the incidental resonance is not caused.

In the above description, the parallel resonance is preferred as the second resonance in FIGS. But,
The second resonance is not limited to the parallel resonance, and the second resonance may be a series resonance by connecting at least one selected from a coil, a capacitor, and a resistor to a predetermined portion of the circuits in FIGS. This can be applied to the circuits shown in FIGS.

For use of the received signal, a signal from a power supply terminal (not shown in FIGS. 1 and 2) connected to the high band antenna conductor 2 is usually sent to the receiver. However, the present invention is not limited to this, and any signal may be sent to the receiver as long as the received signal according to the present invention can be used. The third coil will be described later.

FIG. 3 is a circuit diagram showing a configuration of an application example of the present invention. In FIG. 3, 6 is a high-frequency coil, 19 is a coupling capacitor for blocking DC, 101, 102, 1
03, 104, 105, 106, 107, 108, 10
9, 110, 111 and 112 are damping resistors, 1
9, 120, 121 and 122 are capacitors. FIG.
In the drawings other than FIG. 3, the same numbers as those in FIG.
And the same name.

In the present invention, when the high-frequency coil 6 is provided, and in the case of reception in a low reception frequency band, the high-frequency coil 6 has a low impedance together with the first coil 3. And the high band antenna conductor 2 are connected. The high frequency coil 6 is usually
About 0.1 to 100 μH is used.

When the high receiving frequency band is 10 MHz or more, the high frequency coil 6 has an inductive impedance and has high impedance at least in the high receiving frequency band, and the first coil 3 has a high receiving frequency band. In the obi,
Normally, the self-resonance frequency is low and the inductance is lost, and the high-frequency coil 6 takes over the action.

In other words, the high-frequency coil 6 is an inductance component for supplementing the inductance component of the first coil 3. Normally, the first coil 3 has high impedance at a frequency higher than the low reception frequency band. However, since the first coil 3 is unlikely to have high impedance in a high reception frequency band, the first coil 3 and the high frequency coil 6 have high impedance in a wide frequency band from a low reception frequency band to a high reception frequency band. I have to.

If a wide frequency band from a low reception frequency band to a high reception frequency band can be made high impedance only by the first coil 3, the high frequency coil 6 is unnecessary and can be omitted.

In some cases, a lead wire having an appropriate length can be used as the high-frequency coil 6. However, usually, a solenoid using no magnetic core or a coil using a magnetic core is used. When the high-frequency coil 6 is provided, the first
The sum of the inductance of the coil 3 and the inductance of the high-frequency coil 6 is the inductance that causes the first resonance.

The resistors 101, 102, 103, 104, 1
05, 106, 107, 108, 109, 110, 11
Reference numerals 1 and 112 are damping resistors for adjusting the Q (quality factor) of the resonance. These are all provided as needed, and are unnecessary when adjustment of resonance Q is not necessary.

That is, each damping resistor has a function of reducing the Q of the first resonance or the second resonance.
A value of several tens Ω to several MΩ is adopted. Even without each damping resistor, if the Q due to resonance is small, each damping resistor can be omitted.

The resistors 101, 102, 103, 104, 1
05, 106, 107, 108, 109, 110, 11
1 and 112, the adjustment factor of the resonance Q is different, so that the resistors 101, 102, 103, 104, 105,
One or more selected from 106, 107, 108, 109, 110, 111 and 112 are selected. As each resistance value, a resistance value at which an optimum reception sensitivity characteristic is obtained is appropriately selected and set.

The resistors 104, 105, 106, 107, 1
08, 109 and 110 are Q adjustment resistors (damping resistors) related to the first resonance. Resistance 101, 10
Reference numerals 2 and 103 denote Q adjustment resistors (damping resistors) related to the apparent second resonance. Capacitors 120, 12
Reference numerals 1 and 122 denote capacitors for assisting resonance or preventing noise.

If the resonance frequency of the incident resonance of the second resonance is not within the desired low reception frequency band because the reactive capacitance C _{L1 of the} low band antenna conductor 1 is not sufficiently large, If it does not exist in the vicinity of the reception frequency band, or if the improvement of the reception sensitivity cannot be achieved, by providing the capacitor 120, the capacitance of the reactive capacitance C _L1 is apparently increased, and the apparent second resonance of the desired characteristic is obtained. Is preferably caused. In other words, the capacitor 120 is for adjusting the incident resonance of the second resonance.

If the stray capacitance C _{H1 of the} high band antenna conductor 2 is not sufficiently large, and the resonance frequency of the first resonance does not exist within the desired low reception frequency band, the desired low reception frequency band , Or the improvement of the receiving sensitivity cannot be achieved, the provision of the capacitor 122 increases the apparent capacitance of the stray capacitance C _H1 so as to cause the first resonance of the desired characteristic. Is preferable. In other words, the capacitor 122 is for the first resonance adjustment. The capacitor 121 is also for the first resonance adjustment.

The coupling capacitor 19 is for blocking a DC voltage, cuts a DC voltage and protects each circuit element and a receiver, and is short-circuited at a reception frequency such as a broadcast frequency. Therefore, the coupling capacitor 19 can be omitted if there is no danger that each circuit element or the receiver will fail. The resistors 111 and 112 are resistors for adjusting the effect of the capacitor 122.

Referring to FIG. 3, a combination that is usually easy to adjust will be described.
8, only the high-frequency coil 6, the resistors 101 and 103, and the capacitor 120 are provided. Further, as the second combination, the coils 3, 8, the high-frequency coil 6, and the resistor 1
03 and 105 only. As a third combination, there is a case where only the coils 3 and 8, the high-frequency coil 6, and the resistor 106 are provided.

The first combination is practical and preferred,
The second combination and the third combination are preferable as a simple type. The coils, capacitors and resistors not selected in each combination are not provided.If not provided, those connected in parallel with other circuit elements such as coils will be open,
Those connected in series are short-circuited.

The third coil 18 is for causing the third resonance, and is provided when the reception sensitivity is not sufficient between the first resonance and the second resonance. It is preferable that apparent parallel resonance (third resonance) is caused by the inductance of the third coil 18 and mainly the reactive capacitance C _H1 . Due to this third resonance, three other resonances (accompanying resonances of the third resonance) occur in the system of the entire circuit shown in FIG. 2. This incidental resonance has a strong parallel resonance property.

By the incidental resonance of the third resonance, the reception sensitivity in a desired reception frequency band can be improved. When the incidental resonance of the third resonance is caused, the average receiving sensitivity in the low receiving frequency band is usually improved by about 3 dB or more as compared with the case where the incidental resonance is not caused.

In the above description, FIG.
Is preferably a parallel resonance because the parallel resonance is preferable. However, the third resonance is not limited to the parallel resonance, and FIGS.
The third resonance may be a series resonance by connecting at least one selected from a coil, a capacitor, and a resistor to a predetermined portion of the circuit. This is shown in FIGS.
It can be applied to the circuit of FIG.

FIG. 4 is a circuit diagram of another type of the basic structure of the present invention different from FIG. 1, and FIG. 5 shows an equivalent circuit diagram of FIG.

In the present invention shown in FIG. 4, similarly to the case of the present invention shown in FIG. 1, when receiving a low reception frequency band, the first coil 3 has a low impedance, and thus the low band antenna conductor is used. 1 and the high band antenna conductor 2 are connected.
In this case, series resonance (first resonance) is caused by the inductance of the first coil 3 and mainly the reactive capacitance C _H1 .

By the first resonance which is the series resonance, a parallel resonance occurs due to a reactance (series resonance reactance) due to the series connection of the first coil 3 and the reactive capacitance C _H1 and the reactive capacitance C _L1 . The operation and effect in this case are the same as those shown in FIG.

Also, in the present invention shown in FIG. 4, similarly to the present invention shown in FIG. 1, the low band antenna conductor 1 has an ineffective capacitance C _L1 , and the inductance of the second coil 8 and mainly the ineffective capacitance C _L1. It is preferable to cause apparent parallel resonance (second resonance) with _H1 . When the second resonance occurs, an incidental resonance of the second resonance occurs. That is, when the parallel connection of the second coil 8 and the reactive capacitance C _H1 and the serial connection of the first coil 3 are referred to as a series combined reactance, the second resonance is determined by the series combined reactance and the reactive capacitance C _L1. Associated resonance occurs.

FIG. 6 is a circuit diagram showing a configuration of an application example of FIG. In FIG. 6, 6 is a high-frequency coil, 201, 20
2, 203, 204, 205, 206, 207, 20
8, 209, 210, 211 and 212 are damping resistors, and 220, 221 and 222 are capacitors.

The operation and effect of the high-frequency coil 6 in FIG. 6 are the same as in the case shown in FIG. Resistor 201,
202, 203, 204, 205, 206, 207, 2
08, 209, 210, 211, 212 correspond to the resistors 101, 102, 103, 104, 10 in FIG.
5, 106, 107, 108, 109, 110, 11
1 and 112, respectively, and the operation and effect are the same as those shown in FIG. The capacitor 19 is for blocking direct current. The capacitors 220, 221 and 222 correspond to the capacitors 120, 121 and 122.

The function of the high-frequency coil 6 in FIG. 6 is the same as the function of the high-frequency coil 6 in FIG.

Also, in the present invention shown in FIGS. 1 and 4, when the first resonance is a series resonance and the second resonance is an apparent second resonance, as described above, two second resonances are generated. An accompanying resonance occurs.

With respect to the resonance frequencies of the incidental resonances of these two second resonances, the resonance frequency of one incidental resonance (hereinafter referred to as the first resonance of the second resonance) starts from the substantially center frequency of the low reception frequency band. It is preferable that the resonance frequency of the other associated resonance (hereinafter referred to as a second associated resonance frequency of the second resonance) and the remaining associated resonance frequency be present in a high frequency range or a low frequency range, respectively. One of these two incident resonances
This is because a flat reception sensitivity characteristic can be achieved by dividing and sharing one reception frequency band.

Here, flat reception sensitivity means that the difference between the highest reception sensitivity and the lowest reception sensitivity is small within a band such as a desired broadcast frequency band.

The highest frequency in the low reception frequency band is f _H
If a, the presence of first accompanying resonance frequency of the second resonance between the substantially center frequency of 1.5 times the frequency and the low receiving frequency band of f _H, and the lowest frequency of the low receiving frequency band If the set to f _L, flat second second be present concomitant resonant frequency, the receiving sensitivity of the resonance between the substantially center frequency of 0.6 times the frequency and the low receiving frequency band f _L It is particularly preferable from the viewpoint of chemical conversion. Outside this range, the flatness of the receiving sensitivity in a low receiving frequency band is poor.

To achieve this, when the center frequency of the low reception frequency band is f _M , both the resonance frequency of the first resonance and the apparent resonance frequency of the second resonance are usually f _M
Is present between 1.4 times the frequency of 0.6 times the frequency and f _M of the _M.

As described above, the range of the resonance frequency of each resonance is not limited to the AM broadcast band (medium wave) and the FM broadcast band, but is also the same for the short wave, long wave, ultra-short wave, and the like. The required range of the frequency can be determined.

In order to satisfy the condition of the resonance frequency range of each resonance, the impedance of the low band antenna conductor 1 and the high band antenna conductor 2 mainly due to the stray capacitance is fixed. 3, a capacitor 12 that changes at least one of the second coil 8, the third coil 18, and the high-frequency coil 6 or supplements the stray capacitance
By providing and connecting 0, 121, and 122, the positions of the first resonance frequency, the second resonance frequency, and the third resonance frequency are adjusted.

The low band antenna conductor 1 and the high band antenna conductor 2 may be provided on separate window glass plates. For example,
The low band antenna conductor 1 is provided on the rear window glass plate, and the high band antenna conductor 2 is provided on the side window glass plate. However, for convenience in mounting, it is preferable that both the low band antenna conductor 1 and the high band antenna conductor 2 are provided on the same window glass plate. As the cable connecting the high band antenna conductor 2 and the receiver, a coaxial cable, a feeder line, or the like is usually used.

Regarding the Q of each resonance, the difference between the highest reception sensitivity and the lowest reception sensitivity in the low reception frequency band is about 1 to 1 so that the reception sensitivity is as flat as possible in the low reception frequency band.
Preferably, it is set in a range of about 16 dB.

The difference between the highest receiving sensitivity and the lowest receiving sensitivity is about 1
If it is less than dB, the effect of each resonance is almost eliminated, and the average receiving sensitivity is lowered by several dB to several tens dB, which is not preferable. If the difference between the highest receiving sensitivity and the lowest receiving sensitivity exceeds about 16 dB, not only the variation in the receiving sensitivity becomes large, but also in the case of mass production, the variation in the frequency characteristics of the receiving sensitivity of each product becomes undesirably large.

A more desirable range of the difference between the highest receiving sensitivity and the lowest receiving sensitivity is a range of about 2 dB to about 13 dB,
A particularly desirable range is from about 4 dB to about 10 dB. By setting the difference between the highest reception sensitivity and the lowest reception sensitivity in the above range, the power efficiency from the antenna composed of the antenna conductor 1 for the low band and the antenna conductor 2 for the high band to the receiver can be improved. The high-frequency current of the received signal generated at the receiver can be sent to the receiver without leakage, and the signal can be received with high reception sensitivity.

FIG. 7 shows a case where AM broadcasting band, FM broadcasting band reception, television broadcasting band reception, UHF band reception and the like are assumed, and a case where the present invention is applied to an antenna provided on a rear window glass plate. FIG. 2 shows a basic configuration diagram of an example.

In FIG. 7, 4 is a power supply terminal, 10 is a DC power supply, 20 is a receiver, 31 is a rear window glass plate, 32 is a heater wire, 33 is a defogger which is a ground conductor, and 50 is provided as necessary. It is a low-pass filter. The low band antenna conductor 1 is for an AM broadcast band, and the high band antenna conductor 2 is for an FM broadcast band.

According to the present invention, in the case of AM broadcast reception, the first coil 3 and the high-frequency coil 6 have low impedance, so that the low-band antenna conductor 1 and the high-band antenna conductor 2 are connected. . Also, a first resonance, which is a series resonance, occurs.

The high-frequency coil 6 has an inductive impedance at least in the vicinity of the FM broadcast band and a high impedance in the FM broadcast band.
In the FM broadcasting band, the coil 3 for AM broadcasting band high band resonance usually has a low self-resonant frequency and loses inductance, so the high-frequency coil 6 takes the place of it.

It is preferable that the low-band antenna conductor 1 and the defogger 33 are not capacitively coupled so that the reception signal excited by the low-band antenna conductor 1 does not leak to the vehicle body ground. Usually, if the antenna conductor 1 for low band and the defogger 33 are separated by 30 mm or more, capacitive coupling is difficult in a frequency band of 10 MHz or less.

As shown in FIG. 7, the defogger 3
When 3 is provided, it is preferable to provide a low-pass filter 50 having a low reception frequency band as a cutoff band.
As a result, high reception sensitivity can be achieved while preventing engine noise current superimposed on the DC power supply line from flowing to the defogger, and both reception sensitivity and S / N can be improved.

FIG. 8 is a circuit diagram of a typical example of the low-pass filter 50, which has a T-type filter configuration. In FIG. 8, 41 and 42 are coils, and 43 is a capacitor. FIG. 9 is a circuit diagram of a different type of the low-pass filter 50 from FIG. 8, and has a π-type filter configuration. In FIG. 9, 4
6 is a coil, 45 and 47 are capacitors.

In order to allow a large current to flow through the coils 41, 42, and 46, it is preferable to use a thick coil having a wire diameter of 1.0 mm or more. In order to cut engine noise, the self-resonant frequency of the coils 41 and 42 is preferably 60 MHz or more, and more preferably 80 MHz or more. When the self-resonant frequency is 60 MHz or more,
The S / N ratio is improved by approximately several dB at a reception frequency of usually 10 MHz or less as compared with the case where the frequency is less than 60 MHz.

The capacitors 43, 45 and 47 are preferably ceramic capacitors in that the dielectric loss tangent is appropriate and the reliability is high. However, the dielectric loss tangent is correct,
In addition, other types, for example, aluminum electrolytic capacitors can be used if high reliability is ensured.

In FIG. 7, the low-pass filter 50 is connected between the left bus bar and the anode of the DC power supply 10.
However, the present invention is not limited to this, and the low-pass filter 50 can be used even if it is connected between the right bus bar and the vehicle body ground. Further, it is preferable that the connection is made both between the left bus bar and the anode of the DC power supply 10 and between the right bus bar and the vehicle body ground, because the S / N ratio is improved.

In the case where AM broadcast band, FM broadcast band reception, TV broadcast band reception, UHF band reception and the like are assumed in addition to the one shown in FIG. 7, when the present invention is applied to a rear window glass plate, a preferable antenna conductor is used. 10 to 19 show configuration diagrams of the defogger and the defogger.

In FIG. 10, reference numeral 14 denotes a feed terminal of the low band antenna conductor 1, reference numeral 34 denotes a capacitive coupling element provided as required, reference numeral 35 denotes a first short-circuit line, and reference numeral 36 denotes a second short-circuit line. In the drawings other than FIG. 10, the same numbers and the same reference numerals as those in FIG. 10 denote the same names as in FIG.

In FIGS. 11 and 13, reference numeral 51 denotes an extension element of the low band antenna conductor 1 provided as necessary. In FIG. 13, a rightward direction from the vertical portion of the low band antenna conductor 1 near the center in the width direction of the rear window glass plate is indicated by 1.
One or more additional elements may be provided. FIG.
, 5a, 5b and 5c are bus bars. In FIG. 16, reference numeral 52 denotes an additional element of the low band antenna conductor 1 provided as needed.

In FIG. 17, reference numerals 54 and 55 are connection elements for the low band antenna conductor 1 provided as necessary. In FIG. 18, reference numeral 56 denotes a connection element for the low band antenna conductor 1 provided as necessary. FIG.
, 40 is a vehicle body opening, 57 is a connection element of the low band antenna conductor 1 provided as needed, L ₁ ,
L ₂ , L ₃ , L ₄ , L ₅ and L ₆ are intervals.

In the configuration of the antenna conductor and the defogger shown in FIGS. 10 to 19, a part or most of the high band antenna conductor 2 is disposed between the low band antenna conductor 1 and the defogger. It is preferable to do so. More preferably, most are provided.

With such a configuration, the area occupied by the low band antenna conductor 1 is ensured, and impedance matching between the high band antenna conductor 2 and the receiver is facilitated. In addition, high band antenna conductor 2
Is usually about 2 dB or more higher than the case where such an arrangement is not used.

The vertical portion of the high band antenna conductor 2 is the portion that most affects the reception sensitivity in the high reception frequency band, and the vertical portion of the high band antenna conductor 2 is the low band antenna conductor 1.
Preferably as far as possible from the vertical part of the
Specifically, it is preferable to be arranged at a distance of 200 mm or more. Therefore, regarding reception in the high reception frequency band,
In the configuration of the antenna conductor shown in FIGS.
And FIG. 19 are preferable.

In the glass antenna shown in FIGS. 10 to 19, the low band antenna conductor 1 provided in the margin (upper margin) above the defogger of the rear window glass plate preferably has a conductor width of 0.2 to 5 mm. . If the conductor width is less than 0.2 mm, it is difficult to manufacture, and if the conductor width is less than 5 mm, the visual field is obstructed, and there is a safety problem.

In FIGS. 10 to 19, the low band antenna conductor 1 and the high band antenna conductor 2 are provided in the upper margin of the defogger. However, the present invention is not limited to this, and the low band antenna conductor 1 and the high band antenna conductor 2 may be provided in a margin (lower margin) below the defogger of the rear window glass plate.

When the low band antenna conductor 1 is for receiving a frequency band of less than 10 MHz, the low band antenna conductor 1
When provided in the upper margin or lower margin of the rear window glass plate, under the condition of the conductor width of 0.2 to 5 mm,
The total length of the low-band antenna conductor 1 is preferably 7 m / m ² or more, more preferably 20 m / m ² or more per area of the margin. When it is 7 m / m ² or more, the reception sensitivity of several dB is higher than that of less than 7 m / m ² , and when it is 20 m / m ² or more, the reception sensitivity of several dB is lower than that of less than 20 m / m ^2. high.

When the low-band antenna conductor 1 is for receiving a frequency band of less than 10 MHz, it is preferable that the distance between a part or all of the low-band antenna conductor 1 and the vehicle body opening is 10 mm or more. 10 mm if it is 10 mm or more
m, the reception sensitivity is typically 4 dB.
Improve more than a degree.

Even if the distance between a part or the entirety of the low-band antenna conductor 1 and the opening of the vehicle body is 10 mm or more, when the ground conductor connected to the vehicle body ground is provided on the window glass plate, It is preferable that the distance between a part or all of the antenna conductor 1 for use and the ground conductor is 10 mm or more.

When the high-band antenna conductor 2 is for receiving a frequency band of 10 MHz or more, it is preferable that the high-band antenna conductor 2 and the defogger are capacitively coupled close to each other. In the case of capacitive coupling, the receiving sensitivity in the frequency band of 10 MHz or more is higher than that in the case of not capacitive coupling.
Usually, it is improved by about 5 dB or more.

The capacitive coupling between the high band antenna conductor 2 and the defogger is usually capacitively coupled when the distance between the high band antenna conductor 2 and the defogger is about 0.1 to 50 mm.
If it is less than 0.1 mm, it is difficult to manufacture, and if it is more than about 50 mm, the distance is long, so that it is usually difficult to perform capacitive coupling in a frequency band of 10 MHz or more.

10 to 19, a substantially T-shaped capacitive coupling element 34 is provided, and the high-band antenna conductor 2 and the capacitive coupling element 34 are brought close to each other so that the high-band antenna conductor 2 and the defogger can be connected to each other. Are capacitively coupled.
However, the present invention is not limited to this, and may be performed by bringing the high band antenna conductor 2 and the highest-order heater wire 32 directly close to each other. The shape of the capacitive coupling element 34 is not limited to a substantially T shape, and may be a substantially L shape or the like.

In FIGS. 10 to 19, the antenna conductor 2 for high band is used.
(A portion close to the capacitive coupling element 34) is inverted substantially T-shaped. However, it is not limited to this,
The lower part of the high band antenna conductor 2 may be formed in a substantially L-shaped conductor pattern or the like, and the conductor pattern may be directly coupled to the heater wire 32 or the bus bar for capacitive coupling. The invention is not limited to these means, and may be other means.

When the high band antenna conductor 2 is for receiving a frequency band of 10 MHz or more, the distance between a part or all of the high band antenna conductor 2 and the opening of the vehicle body is preferably in the range of 20 to 60 mm. When it is within this range, the receiving sensitivity is usually improved by about 3 dB or more as compared with the case outside this range.

In the present invention, the vehicle body opening means an opening in the vehicle body into which the window glass plate is to be fitted and which should be a vehicle body ground, and is made of a conductive material such as metal.

An auxiliary antenna conductor is not attached to the low band antenna conductor 1 and the high band antenna conductor 2 shown in FIGS. 10 to 19, but is not limited thereto. A substantially T-shaped or substantially L-shaped auxiliary antenna conductor may be attached to the conductor pattern or the feeding point of each antenna conductor.

In the present invention, the number of antenna conductors provided on an automobile is not limited, and the glass antenna device of the present invention and at least one or more selected from other antennas such as a pole antenna and other glass antennas , And diversity reception may be performed.

The diversity reception will be described in detail. The glass antenna device of the present invention is a glass antenna device employing at least one selected from FIGS. 1 and 4, and includes those shown in FIGS. Shall be considered.

The first conceivable configuration for diversity reception utilizes the stronger one of the plurality of reception signals of the plurality of glass antenna devices of the present invention. Here, the received signal corresponds to the received signal at “to receiver” shown in FIGS. 1 and 4.

A second conceivable configuration of diversity reception is that the reception signal of one or more glass antenna devices of the present invention, at least one reception selected from another antenna such as a pole antenna and another glass antenna. Use the stronger of the signals.

In the diversity reception according to the present invention, the combination of the low-band antenna conductor 1 and the high-band antenna conductor 2 (first pair antenna conductor) forming the pair shown in FIGS. The other paired antenna conductor combination (second paired antenna conductor) may be provided on the same window glass plate as the first paired antenna conductor, or may be provided on another window glass plate.

For example, there is a means in which the first paired antenna conductor is provided on one side of the vehicle, for example, a rear side window glass plate, and the second paired antenna conductor is provided on the other side of the vehicle, the rear side window glass plate.

When the present invention is applied to a rear window glass plate, the rear window glass plate is provided with a defogger, the high band antenna conductor 2 and the defogger are capacitively coupled, and a plurality of heater wires are provided. In some cases, it is preferable to short-circuit portions of the plurality of heater wires other than the bus bar with a short-circuit wire.

The number of short-circuit lines may be one, but it may be divided into two as a first short-circuit line 35 and a second short-circuit line 36 as shown in FIG. May be divided into a plurality. More preferred is two divisions.

The first short-circuit line 35 and the second short-circuit line 36 are provided as necessary, and have a function of stabilizing the impedance of the defogger when the defogger is used as an antenna. Further, the first short-circuit line 35 and the second short-circuit line 36 also have a function of broadening the band.

Although not shown in FIGS. 10 to 19, when the capacitive coupling element 34 is not provided, the first short-circuit line 35 and the second short-circuit line 36 are both short-circuited. Protruding from the connection point (intersection) with the heater wire 2,
It may be extended.

[0114] and to use the full defogger as an antenna, the length U ₁ and 0.1 ≦ a ratio of length U ₂ of the second short-circuit line 36 U ₂ / U ₁ of the first short-circuit line 35 It is preferred that ≦ 3. When it is within this range, the reception sensitivity in the high frequency band is usually 1 compared to the case outside this range.
About 3 dB. Further, by adjusting the lengths of U ₁ and U ₂ at this ratio, the effect of widening the band can be promoted.

The first short-circuit line 35 and the second short-circuit line 36 need not be located at the center of the defogger in the horizontal direction. However, in order to achieve good impedance matching, the first short-circuit line 35 and the second short-circuit line 36 are located substantially at the center of the defogger in the horizontal direction. It is preferable that the first short-circuit line 35 and the second short-circuit line 36 are provided. Further, it is preferable that the first short-circuit line 35 and the second short-circuit line 36 intersect the heater wire 2 substantially at a right angle. This is to prevent the heater current from flowing through the first short-circuit line 35 and the second short-circuit line 36 as much as possible.

It is not necessary to short-circuit all the heater wires 2 with the first short-circuit line 35 and the second short-circuit line 36. The first short-circuit line 35 and the second short-circuit line 36 may be a single short-circuit line.
Need not be short-circuited.

In FIGS. 10 to 19, the power supply terminals 4 and 14 are disposed on the left peripheral portion of the rear window glass plate. But,
The present invention is not limited to this, and may be provided at any position of the rear window glass plate. For example, the rear window glass plate may be provided at the upper and lower peripheral edges at the left and right center.

Although the defogger shown in FIGS. 7 and 10 has a so-called C-shape, the defogger according to the present invention is not limited to this, and is a so-called U-shaped defogger as shown in FIG. Can also be used in the present invention.

In the defogger shown in FIG. 12, the bus bar on the right side of the bus bars on both sides of the defogger is vertically divided into two from a desired position, and the lower bus bar 5a and the upper bus bar 5 are divided.
b is provided. The lower bus bar 5a is connected to a lead wire for grounding the vehicle body, and the upper bus bar 5b is connected to a lead wire on the anode side of a DC power supply. The supplied current flows in a U-shape from the upper bus bar 5b to the lower bus bar 5a through the bus bar 5c.

The rear window glass plate 31 shown in FIG. 19 is usually a tempered glass plate of about 3 to 5 mm or a laminated glass plate. An electrically heated defogger 33 having a large number of heater wires and opposed bus bars connected to both ends of the heater wire group is provided in a heated area on the inner side surface of the rear window glass plate 31, and the defogger 33 is provided. Are connected to lead wires.

The defogger 33 shown in FIG. 19 includes a heater wire 32 and a bus bar. The heater wires 32 are usually formed by forming a large number of thin, electrically heated heater wires having a line width of 0.5 to 2 mm substantially parallel to the horizontal direction on the glass plate at an interval of 2 to 4 cm.

Further, bus bars for supplying a current to the heater wire 32 are formed on both sides of the heater wire. The heater wire, the bus bar and the antenna conductor 1 for the low band and the antenna conductor 2 for the high band are usually formed by printing a conductive metal-containing paste such as a conductive silver paste on the inside surface of the glass plate and baking it. To manufacture.

The pattern of the high band antenna conductor 2 is not limited to AM broadcasting or FM broadcasting, but may be AM broadcasting, FM broadcasting, AM broadcasting depending on the specifications and shape of the automobile, the shape, dimensions, and configuration of the glass plate. And FM broadcasting, or a pattern that provides the optimum performance as an antenna for broadcasting or other broadcasting, is appropriately selected and designed.

In the case of FIG. 10 to FIG. 19, the low band antenna conductor 1 and the high band antenna conductor 2 are provided in the upper margin of the window glass plate 31.
As described above, the position of the window glass plate 31 provided with the low band antenna conductor 1 and the high band antenna conductor 2 is shown in FIGS.
The position is not limited to the position shown in FIG. 19 and may be a lower margin portion of the glass plate 31. Further, they may be provided in the upper and lower portions of the defogger 33, respectively, or may be provided in other margins.
Further, another antenna conductor other than the low band antenna conductor 1 and the high band antenna conductor 2 may be provided on the window glass plate 31.

In FIGS. 10 to 19, as the window glass plate,
Although the rear window glass plate 31 provided with the defogger has been illustrated, the present invention is not limited to this, and even if the window glass plate is not provided with a defogger, the front window glass plate, the front side window glass plate may be used. , A rear side window glass plate, a roof window glass plate and the like can also be used.

The window glass plate is a multi-layer glass plate in which a heat insulating layer such as an air layer, a vacuum layer, or a gas layer other than air is interposed between the two glass plates of the first glass plate and the second glass plate. In some cases, if the low band antenna conductor 1 is provided on the first glass plate and the high band antenna conductor 2 is provided on the second glass plate, a small space can be effectively used.

FIG. 20 is a circuit diagram of a basic configuration for explaining the principle of an application example of the present invention. In FIG.
1 'is a low band antenna conductor 1 different from the low band antenna conductor 1 (hereinafter, referred to as a second low band antenna conductor), 2'
Is a high band antenna conductor different from the high band antenna conductor 2 (hereinafter, referred to as a second high band antenna conductor), 7 is a phase adjustment circuit provided as necessary, and P ₁ is a high band antenna conductor. 2 and 'connection point or points of high band antenna conductor 2, P ₂ is high band antenna conductor 2' high band antenna conductor 2 points, P ₃ is a point of the high band antenna conductor 2.

In the drawings other than FIG. 20, the same numbers as those in FIG. 20 and the names of the same reference numerals are the same as those in FIG. In the description of FIG. 20, the low band antenna conductor 1 of FIG. 20 is referred to as a first low band antenna conductor 1, and the high band antenna conductor 2 of FIG. 20 is referred to as a first high band antenna conductor 2. The dotted line shown in FIG. 20 indicates a window glass plate different from the window glass plate on which the first low band antenna conductor 1 is provided.

As an application example of the present invention, as shown in FIG. 20, a first low band antenna conductor 1 and a second low band antenna conductor 1 'may be connected. The number of low band antenna conductors connected to each other is not limited. In other words, it is preferable to provide a plurality of low-band antenna conductors as low-band antenna conductors on the window glass plate and to connect the low-band antenna conductors in terms of improving the reception sensitivity.

The plurality of low band antenna conductors connected to each other may be provided on the same window glass plate, or may be provided on separate window glass plates. Further, one or more low-band antenna conductors provided on the window glass plate may be connected to one or more low-band antenna conductors provided on a portion other than the window glass plate. The connection of the plurality of low band antenna conductors can be similarly applied to the high band antenna conductor.

When a plurality of low band antenna conductors are connected, it is not always necessary to provide and connect a plurality of high band antenna conductors, and only one high band antenna conductor may be used. Similarly, when connecting a plurality of high band antenna conductors, it is not always necessary to provide and connect a plurality of low band antenna conductors, and only one low band antenna conductor may be used.

Although the phase adjusting circuit 7 is not necessarily required, the phase adjusting circuit 7 can reduce the phase difference between the first high band antenna conductor 2 and the second high band antenna conductor 2 '. Therefore, it is preferable to provide the phase adjustment circuit 7. When the phase adjustment circuit 7 is provided, the reception sensitivity is improved by about 3 dB or more in a high reception frequency band as compared with the case where the phase adjustment circuit 7 is not provided. When the phase adjustment circuit 7 is not provided, the first high band antenna conductor 2 and the second high band antenna conductor 2 'are directly connected.

The concept of FIG. 20 can be applied to the circuit of FIG. 4, and if the concept of FIG. 20 is applied to FIG.
Similarly, the connection point between the first low-band antenna conductor 1 and the second low-band antenna conductor 1 ′ is between the first low-band antenna conductor 1 and the third coil 18. The connection point between the first high band antenna conductor 2 and the second high band antenna conductor 2 ′ is between the first high band antenna conductor 2 and the second coil 8.

FIG. 21 is a circuit diagram of a typical example of the phase adjustment circuit 7. In FIG. In FIG. 21, reference numeral 250 denotes a variable coil;
Is a capacitor. Usually, the variable coil 250 is 33n
H to 1 μH, and the capacitor 251 employs 5 to 1000 pF. The phase adjustment circuit 7 is not limited to the circuit shown in FIG.

In the present invention shown in FIG. 20, the number of antenna conductors provided on a vehicle is not limited.
Diversity reception may be performed between the glass antenna device of the present invention shown in FIG. 20 and at least one or more selected from another antenna such as a pole antenna and another glass antenna.

The diversity reception will be described in detail. The glass antenna device of the present invention shown in FIG. 20 includes those in which FIGS. 3, 4 and 6 are applied to FIG.

Here, the first conceivable configuration for diversity reception utilizes the stronger one of the plurality of received signals of the plurality of glass antenna devices of the present invention. Here, the received signal corresponds to the received signal at “to receiver” shown in FIG.

A second conceivable configuration for diversity reception is that the reception signal of one or more glass antenna devices of the present invention is combined with at least one or more other antennas such as a pole antenna and another glass antenna. Use the stronger of the received signals.

A third conceivable configuration of diversity reception satisfies the above first or second diversity reception, and connects the high band antenna conductor 2 and the high band antenna conductor 2 ′ at the connection point P ₁ . without, for when receiving a high receiving frequency band, the received signal point P _1, the point P ₂ of the received signal, the present invention high band antenna conductor received signal or required according to the provided if necessary The stronger one of the reception signals of the antenna conductor for the high reception frequency band different from the present invention provided according to the present invention is used.

The fourth conceivable configuration of diversity reception satisfies the first or second diversity reception as required, and connects the high-band antenna conductor 2 and the high-band antenna conductor 2 ′ to the connection point P. ₁ and the point P _{3 of} the high band antenna conductor 2 is not connected to the point P _1, and the point P _{2 is} not connected.
DOO point P ₃ each connected to another input terminal of the switch circuit (not shown). The output of the switch circuit is connected to the point P _1. Thus by connecting, connecting the stronger of the received signal at the point P ₂ and the point P ₃ controls the switch circuit to the point P ₁ by the selection signal from the receiver. The switch circuit may be either a mechanical switch such as a relay or a semiconductor switch such as an FET or a bipolar transistor.

The window glass plate provided with each antenna conductor includes, for example, the first low band antenna conductor 1 and the first low band antenna conductor 1.
And the second low-band antenna conductor 1 ′ is provided on one side of the vehicle, for example, on the rear side window glass plate.
And the second high band antenna conductor 2 ′ are provided on the other rear side window glass plate on the other side of the vehicle.

FIG. 22 shows a configuration diagram of an example of an antenna conductor when the present invention is applied to a rear side window glass plate. In FIG. 22, reference numeral 60 denotes a rear side window glass plate. FIG.
In 2, the positions of the feeding points 4 and 14 are not particularly limited in terms of reception characteristics, but are preferably provided as close to the periphery of the window glass plate as possible in order to ensure visibility.

Further, all the antenna conductors according to the present invention are provided on one side of the vehicle, for example, on a side window glass plate, and
It may be set to 0. It may be provided separately on both side window glass plates, as shown in FIG. When provided separately on both side window glass plates, it is preferable to perform diversity reception between the glass antennas of both side window glass plates in order to improve directivity. Regarding the application of the present invention to the side window glass plate, the rear side window glass plate is most suitable among the side window glass plates in order to make it difficult to obstruct the field of view.

Although FIG. 1 illustrates the rear window glass plate 31 provided with a defogger as the window glass plate, the present invention is not limited to this. Can be used. In addition, a front window glass plate, a side window glass plate, a roof window glass plate, or the like can be used as the window glass plate.

FIG. 26 shows a simplified example of the present invention. In FIG. 26, 601 is a second high-frequency coil,
602 is a third high-frequency coil, and 700 is a capacitor. FIG. 27 shows an equivalent circuit of FIG. 26 and 27, the second high-frequency coil 601 and the third high-frequency coil 602 have the same electrical characteristics as the first high-frequency coil 6. 26 and 27, the basic operation of the circuit shown in FIGS. 26 and 27 is the same as that of the circuit shown in FIG. 1 except that the high band antenna conductor 2 shown in FIG. 1 is not provided.

The low-band antenna conductor 1 is used as a dual-purpose antenna conductor for the low reception frequency band and the high reception frequency band. Instead of the low band antenna conductor 1, an antenna conductor suitable for receiving both the low reception frequency band and the high reception frequency band may be provided.

Further, between the low band antenna conductor 1 and the receiver, the one in which the first coil 3 and the capacitor 700 are connected in parallel is connected. As in the case of FIG.
The inductance value of the coil is low impedance at least in a low reception frequency band.

The capacitor 700 has a capacitance value such that the impedance becomes low in a high reception frequency band and the impedance becomes high in a low reception frequency band. Therefore, the received signal in the high receiving frequency band excited by the low band antenna conductor 1 is sent to the receiver via the capacitor 700. The capacitance value of the capacitor 700 is generally 1 to 1000
About pF is adopted. For example, if the low reception frequency band is AM
When the broadcasting band and the high reception frequency band are the FM broadcasting band, the capacitance value of the capacitor 700 is preferably in the range of 5.0 to 33 pF.

The second high-frequency coil 601 and the third high-frequency coil 602 are provided as necessary, so that the reception signal of the high reception frequency band excited by the low-band antenna conductor 1 does not leak to the vehicle body ground. It is for doing. Usually, it is sufficient to provide one of the second high-frequency coil 601 and the third high-frequency coil 602.

A second high-frequency coil 601 and a third high-frequency coil 602 are provided, and the second high-frequency coil 601 and the third high-frequency coil 602 have low impedance when receiving in a low reception frequency band. The second high-frequency coil 601 and the third high-frequency coil 602 usually have a capacity of 0.1 mm.
About 1 to 100 μH is used.

The second high-frequency coil 601 and the third high-frequency coil 602 have a high impedance at least in a high reception frequency band, and the second coil 8 generally has a self-resonant frequency in the high reception frequency band. The second high-frequency coil 601 or the third high-frequency coil 602 substitutes for the low frequency and loss of inductance.

If a wide frequency band from a low reception frequency band to a high reception frequency band can be made high impedance only by the second coil 8, the second high frequency coil 601 or the third
The high frequency coil 602 is unnecessary and can be omitted.

In addition, the first coil 3 and the first other element cause the first resonance to occur, and the resonance frequency of the first resonance exists in a band lower than the high reception frequency band. . Further, an end of capacitor 700 opposite to the low-band antenna conductor 1 is connected to the receiver by a cable. It is preferable that the second coil and the second other element cause an apparent second resonance.

As shown in FIG. 4, the second coil 8 may be provided at the position of the third coil 18 in FIG. The basic operation of the circuit in this case is the same as the basic operation of the circuit shown in FIG.

The use of the present invention mainly for improving the receiving sensitivity will be described. As shown in FIG. 28, an electrically heated defogger 33 having a heater wire 32 and a bus bar for supplying power to the heater wire 32 is provided on the rear window glass plate 31, and between the bus bar and the DC power supply 10 and between the bus bar and the vehicle body ground. The choke coil 139 is connected between them, and the impedance of the choke coil 139 is increased in a high frequency band such as a broadcast frequency band, so that the current in the broadcast frequency band from the DC power supply 10 to the defogger 33 is cut off.

In this manner, at least one of the low band antenna conductor 1 and the high band antenna conductor 2 is connected to the defogger 3.
3 and capacitively coupled. As a result, the received signal of the capacitively coupled antenna conductor becomes stronger, and the receiving sensitivity is improved.

When the low-band antenna conductor 1 or dual-purpose antenna conductor of FIG. 26 is capacitively coupled close to the defogger 33, the reception sensitivity is improved in both a low reception frequency band and a high reception frequency band.

In the case of using the present invention shown in FIG. 26, the means for interrupting the broadcast frequency band current to the defogger 33 is different from that shown in FIG. 28 in that a choke coil is provided only between the bus bar and the DC power supply 10. The choke coil may be connected only between the bus bar and the vehicle body ground.

[0159]

【Example】

(Example 1) A glass antenna device was manufactured on the premise of receiving AM broadcast and FM broadcast. The low reception frequency band is the AM broadcast frequency band, and the high reception frequency band is the FM broadcast frequency band. A glass antenna device including the circuit shown in FIG. 3 and the conductor pattern shown in FIG. 19 was produced. A first short-circuit line 35,
The second short-circuit line 36 and the capacitive coupling element 34 were provided.

In the circuit shown in FIG. 3, a first coil 3, a second coil 8, a high-frequency coil 6, a resistor 101, a resistor 103, a capacitor 120 and a coupling capacitor 19 are selectively provided. No other coils, resistors or capacitors were provided. The first coil 3 is of a chip type and has a relatively wide band.

Regarding the value of each circuit element, the first coil 3 is 3 in the AM broadcast frequency band (500-1500 kHz).
30 μH and 180 μH for the second coil 8. Also,
In the FM broadcast frequency band (88 to 108 MHz), the high frequency coil 6 is 1.0 μH, and in the AM broadcast frequency band and the FM broadcast frequency band, the resistance 101 is 100Ω and the resistance 103 is 3.6 k.
Ω, the capacitor 120 was 47 pF, and the coupling capacitor 19 was 0.01 μF.

For each dimension of the conductor pattern shown in FIG. 19, L ₁ is 30 mm, L ₂ is 10 mm, and L ₃ is 120 mm.
0 mm, L ₄ was 400 mm, L ₅ is 100 mm, L ₆ and 125 mm.

The distance between the lowermost part of the high band antenna conductor 2 and the capacitive coupling element 34 (capacitance coupling part) is 3.0 mm, and the distance between the low band antenna conductor 1 and the vehicle body opening (upper part of the window). The shortest distance was approximately 20 mm. The maximum width of the defogger was 1,400 mm, the maximum length of the defogger was 535 mm, and the heater wires were 16 at equal intervals of 35 mm. The length of the first short-circuit line 35 is 245 mm,
The length of the second short-circuit line 36 was 245 mm.

Further, the effective capacitance C of the low band antenna conductor 1
_L0 is approximately 10 pF, the stray capacitance C of the antenna conductor 1 for low band.
_L1 is approximately 50 pF, the effective capacitance C of the high band antenna conductor 2
_H0 is approximately 8 pF, and the capacitance C _H1 of the sum of the floating capacitance of the high band antenna conductor 2 and the floating capacitance of the cable (not shown) is approximately 1
It was 55 pF.

The measurement result of the reception sensitivity is as shown by the solid line in FIG. 23 for the AM broadcast frequency band. In FIG. 23, a pole antenna having a length of 500 mm is almost -65d.
B. The FM broadcast frequency band was almost equivalent to a pole antenna having a length of 500 mm (within ± 2 dB).

In FIG. 23, the resonance frequency of the first resonance is approximately 700 kHz, and the resonance frequency of the second resonance is approximately 1 kHz.
At 200 kHz, the first incident resonance frequency of the second resonance was approximately 500 kHz, and the second incident resonance frequency of the second resonance was approximately 1580 kHz.

(Example 2) Second coil 8 and capacitor 12
Other specifications were the same as in Example 1 except that 0 was not provided. The measurement result of the reception sensitivity is as shown by a dotted line in FIG. 23 for the AM broadcast frequency band, and is approximately 1100 to 1500 kHz when compared with a pole antenna having a length of 500 mm.
It can be seen that in the range of z, the receiving sensitivity is higher than that of the pole antenna.

Further, as shown in FIG. 23, compared with Example 1, the flatness of the reception sensitivity in the entire AM broadcast frequency band,
It can be seen that the average receiving sensitivity of Example 1 is superior. F
The M broadcast frequency band was the same as in Example 1.

In FIG. 23, the resonance frequency of the first resonance is approximately 700 kHz, and the resonance frequency of the parallel resonance caused by the first resonance is approximately 1370 kHz.

Example 3 Capacitive Coupling Element 34, First
No short-circuit line 35 and second short-circuit line 36 were provided, and the high-band antenna conductor 2 and the defogger were not capacitively coupled.
Other specifications were the same as in Example 1. The measurement result of the reception sensitivity was as shown by the solid line in FIG. 23 for the AM broadcast frequency band, which was the same as in Example 1. With respect to the FM broadcast frequency band, the average reception sensitivity in the FM broadcast frequency band was approximately 6 dB lower than in Example 1.

(Example 4) Although the capacitive coupling element 34 was provided, the first short-circuit line 35 and the second short-circuit line 36 were not provided, and other specifications were the same as in Example 1. The measurement result of the reception sensitivity was as shown by the solid line in FIG. 23 for the AM broadcast frequency band, which was the same as in Example 1. Regarding the FM broadcast frequency band, the average reception sensitivity in the FM broadcast frequency band is as shown in Example 3.
It was almost 4.0 dB more.

(Example 5) The short-circuit line connecting each heater line is not divided into the first short-circuit line 35 and the second short-circuit line 36, but one short-circuit line. Connected. The length of the short-circuit line was 525 mm. Other specifications were the same as in Example 1.

The measurement result of the reception sensitivity is as shown by the solid line in FIG. 23 for the AM broadcast frequency band, which is the same as in Example 1. With respect to the FM broadcast frequency band, the average reception sensitivity in the FM broadcast frequency band was approximately 4.5 dB higher than in Example 3.

(Example 6) A first short-circuit line 35 connected the highest heater wire and a total of four heater wires from the highest to the fourth. In addition, a total of 12 heater wires from the fifth heater wire from the highest to the lowest heater wire were connected by the second short-circuit line 36. The length of the first short-circuit line 35 is 105
mm, and the length of the second short-circuit line 36 was 385 mm. Other specifications were the same as in Example 1.

The measurement result of the receiving sensitivity is as shown by the solid line in FIG. 23 for the AM broadcast frequency band, which is the same as in Example 1. With respect to the FM broadcast frequency band, the average reception sensitivity in the FM broadcast frequency band was approximately 4.5 dB higher than in Example 3.

(Example 7) A total of twelve heater wires from the highest heater wire to the twelfth heater wire were connected by the first short-circuit wire 35. In addition, the second short-circuit line 36 provides a total of 4 from the 13th heater wire from the highest to the lowest heater wire.
The heater wires were connected. The length of the first short-circuit line 35 is 3
85 mm, and the length of the second short-circuit line 36 was 105 mm. Other specifications were the same as in Example 1.

The measurement result of the reception sensitivity is as shown by the solid line in FIG. 23 for the AM broadcast frequency band, which is the same as in Example 1. The FM broadcast frequency band was the same as in Example 1.

(Example 8) A total of 14 heater wires from the highest heater wire to the 14th heater wire were connected by the first short-circuit wire 35. In addition, the second short-circuit line 36 provides a total of 2 from the 15th heater wire from the highest to the lowest heater wire.
The heater wires were connected. The length of the first short-circuit line 35 is 4
55 mm, and the length of the second short-circuit line 36 was 35 mm.
Other specifications were the same as in Example 1.

The measurement result of the receiving sensitivity is as shown by the solid line in FIG. 23 for the AM broadcast frequency band, which is the same as in Example 1. With respect to the FM broadcast frequency band, the average reception sensitivity in the FM broadcast frequency band was approximately 4.5 dB higher than in Example 3.

(Example 9) As shown in FIG.
Other specifications were the same as in Example 1 except that a low-pass filter 50 having a low reception frequency band as a cutoff band was connected between the DC power supply 3 and the DC power supply 10.

The coils 41 and 42 of the low-pass filter 50
Was 0.93 μH and the capacitor 43 was 2 μF (FIG. 8). The coils 41 and 42 had a wire diameter of 1.6 mm to allow a large current to flow. The self-resonant frequency of the coils 41 and 42 was 100 MHz. Capacitor 43
Used a ceramic type, the self-resonant frequency was 3 MHz, and the dielectric loss tangent was 1 kHz and 0.01. A low-pass filter was installed on the pillar near the bus bar.
The lead wire length from the low-pass filter to the terminal of the bus bar was about 80 mm.

Compared with Example 1 for the AM broadcast frequency band, the engine noise is 17 dB at the maximum and 1 at the minimum from Example 1.
It was 0 dB smaller. The average reception sensitivity over the entire AM broadcast frequency band is the same as in Example 1, and the average engine noise is 1
It was 3 dB smaller. Regarding the FM broadcast frequency band, both the receiving sensitivity and the S / N ratio were the same as in Example 1.

(Example 10) The production of a glass antenna device was planned on the premise of receiving AM broadcast and FM broadcast. The low reception frequency band is the AM broadcast frequency band, and the high reception frequency band is F
M broadcast frequency band. A glass antenna device including the circuit shown in FIG. 6 and the conductor pattern shown in FIG. 19 was produced.
The first short-circuit line 35, the second short-circuit line 36, and the capacitive coupling element 34 were provided.

In the circuit shown in FIG. 6, the first coil 3, the second coil 8, the high-frequency coil 6, the resistor 203, the resistor 205 and the coupling capacitor 19 are selectively provided. No other coils, resistors or capacitors were provided. The first coil 3 is of a chip type and has a relatively wide band.

Regarding the value of each circuit element, in the AM broadcast frequency band (500-1500 kHz), the first coil 3
30 μH, and the second coil 8 was 330 μH. In the FM broadcasting frequency band (88 to 108 MHz), the high frequency coil 6 was 1.0 μH, the resistance 203 was 6.8 kΩ, the resistance 205 was 12 kΩ, and the coupling capacitor 19 was 0.01 μF in the AM broadcasting frequency band and the FM broadcasting frequency band. . Also,
The dimensions of the conductor pattern shown in FIG. 19 were the same as those in Example 1.

The measurement results of the receiving sensitivity are as shown in FIG. 24 for the AM broadcast frequency band. The characteristics of the FM broadcast frequency band were almost the same as those of Example 1.

(Example 11) In the circuit shown in FIG.
, The second coil 8, the high-frequency coil 6, the third coil 18, the resistor 103, the capacitor 121, and the coupling capacitor 19 are selectively provided. No other coils, resistors or capacitors were provided. First coil 3
Is of a chip type and has a relatively wide band.

Regarding the value of each circuit element, in the AM broadcast frequency band (500-1500 kHz), the first coil 3
70 μH, 390 μH for the second coil 8, and 220 μH for the third coil 18.

Also, the FM broadcast frequency band (88 to 108M
Hz), the high frequency coil 6 was 1.0 μH, the resistor 103 was 6.8 kΩ, the capacitor 121 was 68 pF, and the coupling capacitor 19 was 0.01 μF in the AM broadcast frequency band and the FM broadcast frequency band. See Example 1 for other specifications
The same as above.

The measurement results of the reception sensitivity are as shown in FIG. 25 for the AM broadcast frequency band. A compared to Example 1
It can be seen that both the flatness of the reception sensitivity and the average reception sensitivity over the entire M broadcast frequency band are superior to Example 1. The FM broadcast frequency band was the same as in Example 1.

[0191]

According to the present invention, when a low receiving frequency band is received, the first coil has a low impedance, so that the low band antenna conductor and the high band antenna conductor are connected. As a result, the high band antenna conductor also functions as a part of the low band antenna conductor. for that reason,
The receiving sensitivity in the low receiving frequency band is improved.

Further, the inductance of the first coil and
The first resonance is caused mainly by the stray capacitance or the like of the low band antenna conductor, and the resonance frequency is present at a lower frequency than the high reception frequency band. By the first resonance, the reception sensitivity in a desired low reception frequency band can be further improved.

Further, according to the present invention, by causing the second resonance using the second coil 8, the reception sensitivity in a desired low reception frequency band can be improved, and the reception can be performed with excellent flatness. it can.

Further, in the case where the present invention is applied to a rear window glass plate provided with a defogger, and when receiving a low reception frequency band, the defogger can be prevented from being used as an antenna. A choke coil is not required, which contributes to downsizing of the glass antenna device and improvement in productivity.

In the present invention, when the high band antenna conductor and the defogger are close to each other and capacitively coupled,
Even if a choke coil is not connected between the defogger and the vehicle body ground, the receiving sensitivity can be improved in a high receiving frequency band of 10 MHz or more such as an FM broadcasting band.

In the present invention, the antenna conductor for the AM broadcast band and the antenna conductor for the FM broadcast band are not separately provided on the window glass plate of the automobile as in the conventional glass antenna device. The area occupied by the small area is small, and there are few problems such as deterioration of the visual field.

When a low-band antenna conductor and a high-band antenna conductor are separately provided on a window glass plate of an automobile to receive a low reception frequency band, the low-band antenna conductor and the high-band antenna conductor are connected to each other. By using both antenna conductors, the reception sensitivity in a low reception frequency band can be improved, and efficient reception can be performed.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a basic configuration of the present invention.

FIG. 2 is an equivalent circuit diagram of FIG.

FIG. 3 is a circuit diagram of a configuration of an application example of the present invention.

FIG. 4 is a circuit diagram of another type of the basic configuration of the present invention different from FIG. 1;

FIG. 5 is an equivalent circuit diagram of FIG.

FIG. 6 is a circuit diagram of a configuration of a modification of FIG. 1;

FIG. 7 is a basic configuration diagram of a typical example when the present invention is applied to a rear window glass plate.

FIG. 8 is a circuit diagram of a representative example of a T-type low-pass filter applied to FIG. 7;

FIG. 9 is a circuit diagram of a typical example of a π-type low-pass filter applied to FIG. 7;

FIG. 10 is a configuration diagram of an example of an antenna conductor and a defogger when the present invention is applied to a rear window glass plate.

FIG. 11 is a configuration diagram of another type of antenna conductor and defogger different from FIG. 10;

12 is a configuration diagram of another type of antenna conductor and defogger different from FIG.

FIG. 13 is a configuration diagram of another type of antenna conductor and defogger different from FIG. 10;

FIG. 14 is a configuration diagram of another type of antenna conductor and defogger different from FIG. 10;

FIG. 15 is a configuration diagram of another type of antenna conductor and defogger different from FIG. 10;

FIG. 16 is a configuration diagram of another type of antenna conductor and defogger different from FIG. 10;

FIG. 17 is a configuration diagram of another type of antenna conductor and defogger different from FIG. 10;

18 is a configuration diagram of another type of antenna conductor and defogger different from FIG.

FIG. 19 is a configuration diagram of an antenna conductor and a defogger of another type different from FIG.

FIG. 20 is a circuit diagram of a basic configuration of an application example of the present invention.

FIG. 21 is a circuit diagram of a typical example of a phase adjustment circuit.

FIG. 22 is a configuration diagram of an example of an antenna conductor when the present invention is applied to a rear side window glass plate.

FIG. 23 is a characteristic diagram of reception sensitivity and reception frequency in Examples 1 and 2.

FIG. 24 is a characteristic diagram of reception sensitivity and reception frequency in Example 10.

FIG. 25 is a characteristic diagram of reception sensitivity and reception frequency in Example 11;

FIG. 26 is a basic configuration diagram of a representative example in which the present invention is simplified.

FIG. 27 is an equivalent circuit diagram of FIG. 26;

FIG. 28 is a basic configuration diagram of a conventional example.

[Explanation of symbols]

1: Antenna conductor for low reception frequency band 2: Antenna conductor for high reception frequency band 3: First coil 4: Power supply terminals 5a, 5b, 5c: Bus bar 8: Second coil 10: DC power supply 14: Low band Feeding terminal of antenna conductor 1 18: Third coil 20: Receiver 31: Rear window glass plate 32: Heater wire 33: Defogger 34: Capacitive coupling element 35: First short-circuit line 36: Second short-circuit line 50 : Low-pass filter E _L : Voltage power supply of low band antenna conductor 1 E _H : Voltage power supply of high band antenna conductor 2 C _L0 : Effective capacity of low band antenna conductor 1 C _L1 : Floating of low band antenna conductor 1 C _H0 : Effective capacity of high band antenna conductor 2 C _H1 : Sum of stray capacitance of high band antenna conductor 2 and stray capacitance of cable (not shown) (ineffective capacity)

Claims (4)

[Claims] An antenna conductor for a low reception frequency band and an antenna conductor for a high reception frequency band are provided on a window glass plate of a vehicle, and the antenna conductor for the low reception frequency band and the antenna conductor for the high reception frequency band are provided between the antenna conductors. The first coil is electrically connected, and the inductance value of the first coil is set to be five times or less the input impedance of the receiver in the low reception frequency band, and the antenna conductor for the high reception frequency band and the receiver are connected to each other. It is electrically connected by a cable to transmit the signal of the antenna conductor for the high reception frequency band to the receiver, and the first coil and the sum of the stray capacitance of the antenna conductor for the high reception frequency band and the stray capacitance of the cable are used. A first resonance is caused with a capacitor including a capacitor, a resonance frequency of the first resonance is present at a frequency lower than a high reception frequency band, and a low reception frequency band antenna conductor or A second coil is electrically connected between the antenna conductor for the high reception frequency band and the vehicle body ground, and the second coil and the capacitance including the stray capacitance of the antenna conductor for the low reception frequency band appear to be the second coil. 2. A glass antenna device for a vehicle, wherein the glass antenna device causes the resonance of (2). 2. A dual antenna conductor for a low reception frequency band and a high reception frequency band is provided on a window glass plate of a vehicle, and a first coil and a capacitor are electrically connected between the dual antenna conductor and the receiver. Are electrically connected to each other so that the inductance value of the first coil has a low impedance at least in a low reception frequency band, and the capacitor has a low impedance in a high reception frequency band and a low reception frequency band. The capacitance value is such that the impedance becomes high, and the first resonance is caused by the capacitance including the sum of the stray capacitances of the first coil, the first coil, the antenna conductor for the high reception frequency band, and the cable. So that the resonance frequency of the first resonance exists at a frequency lower than the high reception frequency band. A glass antenna device for a vehicle, wherein the opposite end and the receiver are electrically connected by a cable. 3. An electrically heated defogger having a heater wire and a bus bar for supplying power to the heater wire is provided on a window glass plate of a vehicle, and the bus bar and a DC power supply for the defogger are connected to each other. 2. The glass antenna device for a vehicle according to claim 1, wherein the defogger and the defogger are close to each other and capacitively coupled. 4. A glass antenna device for a vehicle according to claim 1, wherein a circuit including an electrically connected first coil and a high-frequency coil is used in place of the first coil.