JPS5821208Y2 - Kotai Iki Antenna Kenyou Kanetsuitagarasu - Google Patents

Description

[Detailed description of the invention] The present invention relates to a heating plate glass that can be used as a wideband antenna, and particularly to a heating plate glass that can be used as a wideband antenna and is suitable for using a heating conductive wire for anti-fogging attached to the rear window glass of an automobile as a broadband antenna. .

Conventionally, in anti-fog window glass, a plurality of conductive wires are provided on the rear window glass of an automobile, and a current is passed through the conductive wires to heat the glass and prevent the glass from fogging. A capacitor is installed between the heating conductive wire and the antenna feeder to interrupt the heating current flowing through the heating conductive wire and to guide the high frequency current induced in the heating conductive wire to the receiver. An interposed heating plate glass that also serves as an antenna is known.

However, in such a heating plate glass that also serves as an antenna, the high frequency current induced in the heating conductive wire flows into the power supply connected to the heating conductive wire, resulting in an antenna with low gain.

In particular, one terminal of a power source such as a car battery is grounded to the car body, so the heating plate glass that also serves as an antenna for cars has an even lower gain because the high frequency current induced in the heating conductive wire flows directly to the ground. It becomes an antenna.

In order to eliminate these drawbacks, a coil is interposed between the heating conductive wire and the power source, which has a low impedance against the current from the heating power source, and a high impedance against the high frequency current received by the heating plate glass that also serves as an antenna. It has been proposed to prevent the high frequency current induced in the heating conductive wire from flowing to the power supply side.

However, for example, in the heating plate glass that also serves as an antenna, in which a coil with high impedance for AM broadcast waves in the medium wave band is interposed between the heating conductive wire and the heating power source, the coil has a large inductance and at the same time has a relatively large It has a stray capacitance and exhibits low impedance to FM broadcast waves in the ultrahigh frequency band higher than the self-resonance frequency of the coil, and the FM broadcast waves induced in the heating conductive wire flow to the power supply side or ground, and are used as an antenna for AM broadcast waves. Although a relatively high gain can be obtained for FM broadcast waves, only a low gain can be obtained for FM broadcast waves.

On the other hand, in order to minimize the stray capacitance of the coil, a heating plate glass that also serves as an antenna has a coil with high impedance for ultra-high frequency band FM broadcast waves interposed between the heating conductive wire and the heating power source. Since it cannot be used as an antenna, it exhibits a low impedance to AM broadcast waves in the medium wave band, and the AM broadcast waves induced in the heating conductive wire flow to the power supply side, and as an antenna, it has a relatively low impedance for FM broadcast waves. Although high gain can be obtained, there is a drawback that only low gain can be obtained for AM broadcast waves.

The present invention provides a heating plate glass that can be used as a wideband antenna and which can obtain a relatively large gain over a wide band by eliminating the above-mentioned drawbacks. A heating plate glass serving as an antenna that has a conductive wire, a power source for supplying a heating current to the conductive wire, and a means for extracting a high frequency current induced in the conductive wire, the power source and the heating conductive wire. It is characterized by inserting a coil "1?"2 in which a coil L of 0.5μH to 5μH and a coil L2 of 1000μH to 5000μH with a magnetic core are connected in series between the This is a heating plate glass that can also be used as a broadband antenna.

In the present invention, coil L1. It is preferable that L2 be inserted on both sides between the heating conductive wire and the power source in a circuit constituted by the heating conductive wire and the power source, and a pair of coils used on both sides of the circuit are connected to the heating current. It is preferable that the wire be wound in a direction that cancels out the magnetism generated by the wire so that magnetic saturation does not occur.

In the case where the heating plate glass that also serves as an antenna according to the present invention receives FM broadcast waves in the ultrahigh frequency band at a higher frequency and AM broadcast waves in the medium wave band at a lower frequency, the coil L
, it is preferable to use an air-core coil of 0.5 μH to 5 μH (measured value at IKHz), and coil L2 has a magnetic core of 100 μH to 5000 μH (measured value at IKHz).
It is preferable to use a coil with a measured value of

When receiving a higher frequency band, for example, FM broadcasting, using the heating plate glass that also serves as an antenna according to the present invention, the high frequency current induced in the heating conductive wire leaks to the power supply side and the ground side through the coil L1 with small stray capacitance. When receiving AM broadcasting in a low frequency band, for example, the high frequency current induced in the heating conductive wire is blocked by the inductance dog coil L2 with a magnetic core. This prevents leakage to the power supply side and ground side.
A relatively high gain can be obtained, and the heating conductive wire can be used as a high gain antenna over a wide band.

In addition, the heating plate glass that also serves as an antenna according to the present invention has a coil L1 that cuts off the higher frequency band and a coil L2 that cuts off the lower frequency band on the power supply side connected to the heating conductive wire, so the heating plate glass is low. A magnetic core can be used for the coil L2 that cuts off the frequency band of the other side, so that it can have a sufficiently high inductance in that frequency band.
A coil L1 with a small stray capacitance that blocks the higher frequency band is interposed on the heating conductive wire side than the coil L2 which has a magnetic core with a small inductance and a large stray capacitance in the higher frequency band. This makes it possible to maintain high impedance on the power supply side in that frequency band, allowing it to be used as a high-gain antenna over a wide band.

In addition, in the antenna heating plate glass according to the present invention,
By using a pair of coils L2 that have the same magnetic core inserted into both poles of the power supply and are wound in a direction that cancels the magnetism generated by the heating current, the coil L2 itself can be made smaller and the lower frequency band of the coil L2 can be used. Since it can maintain high impedance, it can be used as a high gain antenna, especially in lower frequency bands.

Embodiments of the present invention shown in the drawings will be described below.

In FIG. 1, a plurality of heating conductive wires 12 are provided on the surface of an automobile rear window glass 11 in parallel to each other in the horizontal direction at the longitudinal center of the glass. Collected by 13.14.

The terminal of the bus bar 13 was connected to one end of an air-core coil L1' with an inductance of 3 μH (measured at IKHz) for FM broadcast waves in the ultra-high frequency band, and the negative terminal of the other end of the coil L1 was grounded to the body of the car. A magnetic core 1 having an inductance of about 2000 μH for medium wave AM broadcasting is connected to one end of the positive terminal of the battery 15 via a switch 16.
7 and is connected to the other end of coil L'2 with coil L'2.
A condenser 19 connected to the ground for noise prevention is connected to the switch 16 side of No. 2.

On the other hand, the terminal of the bus bar 14 is connected to one end of a coil bamboo having the same characteristics as the coil L'1, and the other end of the coil L'1 is connected to the coil L/,
It is connected to the other end of a coil L12, which has the same characteristics as , and whose one end is grounded.

Coil L' and coil L''1 are connected to bus bar 13 and bus bar 1, respectively.
The coil L'2 and the coil L''2, which are provided near the coil L'2 and the coil L''2, are magnetically coupled and wound in a direction that cancels the magnetic flux generated by the heating current flowing through each coil.

Further, a capacitor 18 is provided at the upper end of the bus bar 14 to cut off the heating current from the heating conductive wire 12 and to draw out the high frequency current induced in the heating conductive wire 12 to a feeder (not shown).
is provided.

The heating conductive wire 12 of the heating plate that also serves as a wideband antenna configured in this manner has a relatively high impedance to the heating power source and ground, and also to FM broadcast waves and AM broadcast waves. The high frequency current induced in the antenna 12 is guided to a feeder and can be used as a relatively high gain antenna.

The above has shown one embodiment of the present invention, and the present invention is not limited to the above embodiment.

That is, the capacitor 18 does not necessarily have to be drawn out from the bus bar 13, and can be directly connected to the heating conductive wire 12 or the bus bar 13.
and the coil L''.

In addition, as a means for extracting the high frequency current induced in the heating conductive wire, if the point from which the high frequency current is extracted has no potential difference with respect to the ground or is extremely small, the electric potential difference between the high frequency current and the ground is very small, and the electric potential difference between the high frequency current and the ground is very small. You can also take out the antenna feeder.

[Brief explanation of the drawing]

FIG. 1 is a front view and an electric circuit diagram of an automobile rear window glass showing an embodiment of the present invention. 11: Automobile rear window glass, 12: Heating conductive wire, 1
3, 14: Bus bar, 15: Battery, L'1. L"1
:Air-core coil, L12. L"2: Coil with magnetic core.

Claims (1)

[Scope of utility model registration request] A transparent plate glass, a heating conductive wire provided in a heated area of the plate glass, a power source for supplying a heating current to the conductive wire, and a means for extracting a high frequency current induced in the conductive wire. In the antenna-cum-heating plate glass having
1000 μH to 50 with H coil L1 and magnetic core
Coil L1.00 μH and coil L2 connected in series.
A heating plate glass that also serves as a broadband antenna, characterized in that coil L2 is inserted so that coil L2 is on the power supply side.