JP2842581B2 - Antenna-switchable in-vehicle antenna - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna-switchable vehicle-mounted antenna which receives more signals than the number of antennas from two or more antennas.

[0002]

2. Description of the Related Art As a conventional antenna of this type, for example, there is a window glass antenna device (Japanese Patent Application No. 5-324841) filed by the present applicant. FIG. 10 is an overall configuration diagram of a conventional window glass antenna device (Japanese Patent Application No. 5-324841).

The windowpane antenna apparatus 101 comprises a windowpane 102 having a plurality of antennas disposed on a windowpane 102a of an automobile, and a switch 104 for selecting a signal to be input to a wideband amplifier 103.

[0004] The window glass with antenna 102 is provided with two television receiving antennas 105 and 106 and an AM / FM radio receiving antenna 107. These antennas 105, 106, and 107 are body-grounded antennas. Further, the first television receiving antenna 105 is formed with a dedicated antenna pattern, and the second television receiving antenna 106 uses a heater wire 108 for defogging.

[0005] The received signals extracted from the power supply terminals 105a and 106a of the television receiving antennas 105 and 106 are supplied to the input terminals 104a and 104b of the switch means 104 via the power supply cables 105b and 106b.

The switching means 104 includes switching diodes D101 and D102 provided corresponding to the television receiving antennas 105 and 106, and resistors R101 to R101 to supply a direct current to the diodes D101 and D102. R104 and DC blocking capacitors C101 to C104. Terminal 104c,
104d is a switching control terminal.

Each of the resistors R101 to R104 is set to a high resistance value so as not to attenuate the received signal,
The capacitance values of 101 to C104 are set such that the impedance becomes sufficiently low in the frequency band of the received signal.

[0008] The output 104e of the switch means 104 is supplied to an amplifier 103, and the reception signal amplified by the amplifier 103 is supplied to a television receiver (not shown) via a DC blocking capacitor C105.

According to the windowpane antenna 101, the signal of the first television receiving antenna 105 or the second television receiving antenna 106 provided on the windowpane 101 is transmitted to the switch means 104 by the control signal 104 c or 104.
In addition to taking out the signal independently by inputting d, the first antenna 102 and the second antenna 103 are electrically coupled by simultaneously inputting the control signals 104c and 104d, and a combined signal of these antennas is taken out. Was.

[0010]

However, although it was possible to electrically combine a plurality of antennas to extract a combined signal, a plurality of antennas were electrically separated to form a new antenna as a combination of single antenna elements. Nothing was done. Therefore, an object of the present invention is to provide an antenna-switchable vehicle-mounted antenna in which a plurality of antennas are electrically separated to form a new antenna as a combination of single antenna elements.

[0011]

According to the present invention, in order to solve the above-mentioned problems, the present invention comprises a set of coils for suppressing passage of a common-mode current, wherein one end of one of the coils is connected to a first coil.
And one end of the other coil is connected to the second antenna, the other end of the other coil is grounded, and one of the first antenna, the second antenna, and the other end of the one coil is connected to the other antenna. And a changeover switch means for connecting one of them to the receiver.

[0012] In a preferred embodiment of the present invention, a third antenna or more antennas are provided, and the changeover switch means is connected to one of these antennas and the other end of the one coil.
One of which can be switched to connect to the receiver side.

[0013]

According to the first aspect of the present invention, a reception signal of the first antenna or the second antenna composed of the vehicle body ground and the antenna wire is input to the receiver side, respectively. A reception signal of a new non-grounded antenna that does not rely on the grounding of the vehicle body and that is composed of two antennas is input to the receiver. That is, the first antenna and the second antenna are electrically separated from each other, and a new antenna is obtained as a combination of single antenna elements.

According to the second aspect of the present invention, even with three or more antennas, a new antenna one more than the number of antennas can be obtained. In addition, as a new antenna, a new non-grounded type antenna which is constituted by the first antenna and the second antenna and is not based on the grounding of the vehicle body can be obtained.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings. First, an on-vehicle antenna according to claim 1 will be described. FIG. 1 is a main part circuit diagram of a first embodiment of an antenna switching type vehicle-mounted antenna according to the present invention.

An on-vehicle antenna 1 includes a set of coils 2,
It is composed of a first television receiving antenna 3, a second television receiving antenna 4, three-contact switchover means 5, coupling capacitors C1 and C2, and power supply terminals P1 and P2. One end a of one coil L1 is connected to the connection terminal 3a of the first television receiving antenna 3 via the capacitor C1, and one end c of the other coil L2 is connected to the second television receiving antenna via the capacitor C2. The other end d of the other coil L2 is connected to the connection terminal 4a of the antenna 4 and grounded to the vehicle body. Further, the switching terminal e of the changeover switch means 5 is connected to the connection terminal 3a of the first television receiving antenna 3, and the changeover terminal f of the changeover switch means 5 is connected to the connection terminal 4a of the second television reception antenna. The switching terminal g of the switching means 5 is connected to the other end b of one coil L1.
And the common terminal h of the changeover switch means 5 is connected to the power supply terminal P1. The power supply terminal P2 is grounded to the vehicle body.

The coil 2 is a so-called balun. In general, a balun refers to an impedance converter used for balanced / unbalanced conversion, and the balun according to the present invention suppresses passage of common-mode current, that is, a so-called float balun or sorter balun (sort). -A-balun). When the phase difference between the current flowing through the coil L1 and the current flowing through the coil L2 is 180 degrees, the coil (hereinafter referred to as a balun) 2 has no particular effect on the current. In the case of (current), it has the effect of suppressing the passage of current. In the present embodiment, a balun 2 in which two wires are bifilar wound on a toroidal core (not shown) is used. However, the present invention is not limited to the coil wound on the toroidal core. For example, a balun may be formed by an air-core coil.

It is desirable that the inductance of each of the coils L1 and L2 is set in the range of 10 to 50 μH. In this embodiment, for example, both the coils L1 and L2 are set to 25 μH. Further, as the toroidal core, for example, a core material μs850 was used.

FIGS. 2 to 4 are schematic explanatory views showing the relationship between the switch switching terminal and the television receiving antenna. FIG. 2 shows a case where the changeover switch means 5 is connected to the changeover terminal e. In this case, only the reception signal of the television reception antenna 3 is input to the power supply coaxial cable 6 via the power supply terminals P1 and P2 , forming a grounded antenna.

FIG. 3 shows a case where the changeover switch means 5 is connected to the changeover terminal f. In this case, only the reception signal of the television reception antenna 4 is input to the power supply coaxial cable 6 via the power supply terminals P1 and P2, and the ground type antenna is formed.
To achieve.

FIG. 4 shows a case where the changeover switch means 5 is connected to the changeover terminal g. In this case, the signal received by the television receiving antenna 3 via the coil L1 and the coil L
2 and the signal received by the television receiving antenna 4 are input to the power supply coaxial cable 6 via the power supply terminals P1 and P2.

In addition, since the in-phase current among the currents flowing through the coils L1 and L2 is suppressed, the television receiving antenna 3
And 4 are connected to the coaxial cable 6 in an electrically separated state. Therefore, the television receiving antenna 3 and the television receiving antenna 4 form one new non-grounded antenna W as one independent element (pattern) .
You .

In the case of the antenna W, it is considered that the television receiving antenna 3 forms a radiation pattern and the television receiving antenna 4 forms a grounding pattern.

Therefore, the vehicle-mounted antenna 1 is composed of the vehicle-grounded single television receiving antenna 3, the vehicle-grounded television single antenna 4, and the non-grounded television receiving antennas 3 and 4. It is possible to switch to a total of three types of antennas, ie, new antennas W that have been set.

Next, an on-vehicle antenna according to claim 2 will be described. FIG. 5 is a main part circuit diagram of a second embodiment of the antenna switching type vehicle-mounted antenna according to the present invention.

This vehicle-mounted antenna 11 is obtained by adding a television receiving antenna 12 to the vehicle-mounted antenna 1 of the first embodiment, and changing the changeover switch means 5 to four-contact changeover means 13. That is, the connection terminal 12a of the television receiving antenna 12 is connected to the fourth switching terminal i of the switching unit 13. The connection between the other television receiving antennas 3 and 4 and the switching terminals e, f and g is the same as in the first embodiment, and the description is omitted.

Therefore, in the case of the vehicle-mounted antenna 11, the vehicle-grounded television receiving single antenna 3, the vehicle-grounded television receiving antenna 4, the vehicle-grounded television receiving antenna 12, and the non-grounded television receiving antenna 12. New antennas W composed of the television receiving antennas 3 and 4
You can switch to a different antenna.

Even when an antenna other than the television receiving antenna 12 is further added, a new antenna one more than the number of antennas, that is, a new antenna constituted by the non-grounded television receiving antennas 3 and 4 is used. Antenna W can be obtained.

Next, a specific configuration of the vehicle-mounted antenna 11 according to the second embodiment will be described. FIG. 6 is an antenna pattern diagram of the second embodiment, and FIG. 7 is a dimensional diagram of the antenna pattern. If the antenna 12 is omitted from the second embodiment, the antenna pattern becomes substantially the same as that of the first embodiment. or,
The dimensions of the antenna pattern are merely examples, and the present invention is not limited to these dimensions.

The vehicle-mounted antenna 11 includes a rear window glass 20.
A television receiving antenna 12 which shares an upper anti-fog heater 21 disposed in the left-right direction as an antenna, and a television receiving antenna 4 disposed above and to the left of the antenna 12
A television receiving antenna 3 disposed along the upper end of the window glass 20 above the antenna 4 and a main part disposed above the right side of the television receiving antenna 12 and partially extending upward to the left side. A main antenna 21 for AM / FM provided and a sub-antenna 23 for AM / FM in which the lower anti-fog heater 22 is shared as an antenna.

A connection terminal 3a for the television reception antenna 3 and a connection terminal 4a for the television reception antenna 4 are provided on the upper left side of the window glass 20, and the main antenna 21 for AM / FM is provided on the upper right side of the window glass 20. A connection terminal 21 a is provided, and a connection terminal 23 a of the AM / FM sub-antenna 23 is provided below the right side of the window glass 20.

[0032] That is, the vehicle-mounted antenna 11, and the TV da Iba <br/> over City antenna consisting of three TV antenna 3, 4, 12, consisting of two of the AM / FM antenna AM / FM da an antenna with two diversity antennas with Iba over City antennas. Since the configuration of the diversity circuit is the same as that of the conventional diversity antenna, illustration and circuit description are omitted.

Further, in this embodiment, the antenna in which the antenna wire is arranged on the window glass is used as the antenna. However, the present invention is not limited to this antenna. For example, the antenna may be a film-like antenna attached to a window or attached to a vehicle body. It is also possible to use a whip antenna.

In the second embodiment, the switchable on-vehicle antenna is constituted by the television receiving antennas 3, 4, and 12.
The M / FM receiving antennas 21 and 23 can constitute a switchable on-vehicle antenna.

Next, each circuit of the second embodiment will be described. First, the antenna and the changeover switch will be described. FIG. 8 is a circuit diagram of the antenna and the changeover switch means. The circuit diagrams show the antennas 3, 4, 12 according to the present invention.
Is illustrated, and the antennas 21 and 23 are omitted, but the antennas 3 and 4 can be replaced with the antennas 21 and 23.

The on-vehicle antenna 11 has feed terminals P1 and P2.
Is connected to a receiving amplifier 30 to be described later. or,
The in-vehicle antennas 3, 4, and 12 are provided on the rear window glass 20, and the balun 2, the changeover switch means 13, and the receiving amplifier 30 are provided, for example, below a rear tray (not shown) in the vehicle compartment.

The connection between the antennas 3, 4, 12 and the balun 2 is as described above, and the changeover switch means 13 will be described. The changeover switch means 13 specifically uses a combination of mechanical changeover switches S1 to S4 having four contacts and diodes D1 to D4. These switches S1 to S4
Is a known mechanical change-over switch configured to close only one of the four contacts. The received signals at the time of switching are diodes D1-D corresponding to the respective switches S1-S4.
4 to one of the power supply terminals P1 and P2. Capacitors C3, C4, and C5 connected in series to the diodes D1, D2, and D4 are respectively used for passing a reception signal.
The resistors R1 to R8 are for bias. The resistor R9 is also used for bias. The open ends of the resistors R5 to R9 have + B
A voltage is applied.

First, the switch S1 is closed (ON), S2
When S4 is open (off), the anode of the diode D1 is at a low level and the anodes of the diodes D2 to D4 are at a high level, so that only the diode D1 conducts. Therefore, only the reception signal of the antenna 12 is
1, P2.

When the switch S2 is closed (ON), S1, S
When S3 and S4 are open (off), the anode side of the diode D2 becomes low level, and the diodes D1, D3, D4
Becomes high level, so that only the diode D2 conducts. Therefore, only the reception signal of the antenna 3 is input to the power supply terminals P1 and P2.

When the switch S3 is closed (ON), S1, S
2 and S4 are open (off), the anode side of the diode D3 goes low, and the diodes D1, D2, D4
Becomes high level, so that only the diode D3 conducts. Accordingly, in this case, since the balun 2 is connected in series with the diode D3, the reception signals of the antennas 3 and 4 are input to the power supply terminals P1 and P2. In addition, since the common-mode current among the currents flowing through the coils L1 and L2 is suppressed, it is considered that the antenna 3 functions as a radiation pattern and the antenna 4 functions as a ground pattern.

When the switch S4 is closed (ON), S1 to S
When 3 is open (off), the anode side of the diode D4 is at a low level and the anode sides of the diodes D1 to D3 are at a high level, so that only the diode D4 conducts.
Therefore, only the reception signal of the antenna 4 is supplied to the feed terminals P1 and P1.
2 is input.

Instead of the switches S1 to S4, a high level or low level signal may be directly applied to the switch switching terminals S1a to S4a. In this case, the diode becomes conductive when a low level signal is applied. Further, a switching circuit using transistors instead of the diodes D1 to D4 may be used. Although these switch controls are actually performed by a diversity controller (not shown), they are not related to the present invention, so that illustration and description are omitted.

The circuit composed of the resistor R10 and the capacitors C6 and C7 is a power supply circuit having a function of preventing noise when the power is turned on / off.

Next, the receiving amplifier 30 will be described. FIG. 9 is a circuit diagram of the receiving amplifier. The receiving amplifier 30 includes a trap circuit 31, a switching circuit 32, an amplifier circuit 33, and an AGC circuit 34.

The trap circuit 31 includes coils L10, L1
1 and a known trap circuit for attenuating a predetermined frequency signal composed of a capacitor 1 and capacitors C10 to C12.

The switching circuit 32 includes a diode D1
This is a known switching circuit including 0, D11 and resistors R11 to R13, and applies a low-level voltage to an input terminal P3 provided at one end of the resistor R11 and an input terminal P4 provided at one end of the resistor R13. In case, diode D
10 and D11 both conduct, and the received signal from the antenna is input to the amplifier circuit 33. On the other hand, when a high level voltage is applied to both terminals P3 and P4, the diodes D10 and D4
11 are both non-conductive, and the signal received from the antenna is not input to the amplifier circuit 33.

The amplifier circuit 33 includes an NPN transistor Q1, a coupling capacitor C13 connected to the base side of the transistor Q1, and bias resistors R14 and R15.
And a receiving signal passing capacitor C14, bias resistors R16 and R18 and a high-frequency choke L12 connected to the collector side, and a bias resistor R1 connected to the emitter side.
7 and the bypass capacitor C15 and the capacitor C1
4 is a known amplifier circuit constituted by an output terminal P5 connected to the other end of the output terminal P4. Further, a + B voltage is applied to the other end of the resistor R14 and the other end of the high-frequency choke L12. The output terminal P6 is a ground terminal.

AGC (Auto Gain Controller)
ol) circuit 34 includes NPN transistors Q2, Q3
And noise prevention capacitors C16 and C17 connected to the base side of the transistor Q2, and a detection diode D1.
2, a backflow prevention diode D13 and a coupling capacitor C18, and bias resistors R19 and R2 connected between the collector of the transistor Q2 and the base of the transistor Q3.
0 and a capacitor C19 for preventing noise and a capacitor C for bypass connected to the emitter side of the transistor Q3.
20 is a known AGC circuit composed of a high-frequency choke L13 and a high-frequency choke L13. The emitter of the transistor Q2 is grounded, and + B voltage is applied to the collector of the transistor Q3 and the cathode of the diode D13.

Further, by connecting the output terminal of the capacitor C11 and the anode of the diode D10, the trap circuit 31 and the switching circuit 32 are connected, and the diode D
11 is connected to the input terminal of the capacitor C13, the switching circuit 32 and the amplifier circuit 33 are coupled to each other, and the other end of the resistor R18 is connected to the other end of the capacitor C18, so that the amplifier circuit 33 and the AGC circuit 34 are connected.
And the other end of the high-frequency choke L13 and the diode D
10 and D11 are connected to the cathode side,
The C circuit 34 and the switching circuit 32 are coupled. Further, the changeover switch means 13 and the trap circuit 31 are connected via the power supply terminals P1 and P2.

Next, the operation of the receiving amplifier circuit 30 will be described. First, the case where a low level voltage is applied to the input terminals P3 and P4 will be described. In this case, both the diodes D10 and D11 conduct, and the received signal is input to the amplifier circuit 33 via the trap circuit 31. Then, the received signal is amplified by the amplifier circuit 33, and the amplified received signal is input to the AGC circuit 34 via the resistor R18 and the capacitor C18.

The amplified received signal is detected by the diode D12, and a DC signal corresponding to the level of the received signal is input to the base of the transistor Q2. Next, this signal is amplified by the transistors Q2 and Q3 and then input to the base side of the transistor Q1 via the switching circuit 32 to change the gain of the transistor Q1.

That is, since the gain of the transistor Q1 is reduced according to the level of the received signal output from the amplifier circuit 33, a received signal with little distortion even in a strong electric field can be obtained. Since the AGC circuit 34 is provided, a higher gain amplifier circuit can be used as the amplifier circuit 33 than before, and the S / N ratio is also improved.

On the other hand, when a high level voltage is applied to the input terminals P3 and P4, the diodes D10 and D11 become non-conductive, and the reception signal is not input to the amplifier circuit 33.

As described above, according to the present invention, four antennas can be obtained with three antenna patterns. Moreover, as the fourth antenna, a new non-grounded antenna that does not depend on the vehicle body and is composed of the first antenna and the second antenna, that is, an antenna that is considered to be composed of a radiation pattern and a ground pattern is obtained. be able to. Therefore, four diversity antennas suitable for space saving can be obtained.

Further, since the changeover switch means is provided, only one receiving amplifier need be provided for each antenna.

Further, since a high gain receiver amplifier can be used, an amplifier having a good S / N ratio can be obtained.

[0057]

According to the first aspect of the present invention, the reception signal of the first antenna or the second antenna composed of the vehicle body ground and the antenna wire is input to the receiver, respectively, and the first antenna A reception signal of a new non-grounded antenna that does not depend on the vehicle body and is configured by the second antenna and the second antenna is input to the receiver side. That is, the first antenna and the second antenna are electrically separated from each other, and a new antenna is obtained as a combination of single antenna elements.

According to the second aspect of the present invention, even with three or more antennas, a new antenna one more than the number of antennas can be obtained. In addition, as a new antenna, a new non-grounded type antenna which is constituted by the first antenna and the second antenna and is not based on the grounding of the vehicle body can be obtained.

[Brief description of the drawings]

FIG. 1 is a main part circuit diagram of a first embodiment of an antenna switching type vehicle-mounted antenna according to the present invention.

FIG. 2 is a schematic explanatory view showing a relationship between a switch switching terminal of the on-vehicle antenna and the antenna (when switching to a first antenna);

FIG. 3 is a schematic explanatory view showing a relationship between a switch switching terminal of the on-vehicle antenna and the antenna (when switching to a second antenna);

FIG. 4 is a schematic explanatory view showing a relationship between a switch switching terminal and the antenna of the on-vehicle antenna (when the first and second antennas are combined);

FIG. 5 is a main part circuit diagram of a second embodiment of the vehicle-mounted antenna.

FIG. 6 is an antenna pattern diagram of a second embodiment of the vehicle-mounted antenna.

FIG. 7 is a dimensional view of an antenna pattern of a second embodiment of the vehicle-mounted antenna.

FIG. 8 is a circuit diagram of the antenna and the changeover switch means of the vehicle-mounted antenna.

FIG. 9 is a circuit diagram of a receiving amplifier of the vehicle-mounted antenna.

FIG. 10 is an overall configuration diagram of a conventional window glass antenna.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 11 In-vehicle antenna 2 One set of coil (balun) 3 First television receiving antenna 4 Second television receiving antenna 5, 13 Changeover switch means 12 Third television receiving antenna a, c One end of coil b, d The other end of the coil e, f, g, i Switching terminal h Common terminal L1, L2 Coil W New antenna

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-45816 (JP, A) JP-A-2-62183 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01Q 1/00-25/04 H04B 1/18

Claims (2)

(57) [Claims] A first coil connected to a first antenna, one end of the other coil connected to a second antenna, and a second coil connected to a second antenna. A switch switch means for grounding the other end of the coil and connecting any one of the first antenna, the second antenna, and the other end of the one coil to the receiver side ,
By switching the changeover switch, the first antenna and the
Form a single grounded antenna with each of the two antennas
Of the first antenna and the second antenna
One consists of a radiation pattern and the other is a ground pattern
An antenna switching type on-vehicle antenna, wherein a non-grounded antenna is formed . 2. The apparatus according to claim 1, further comprising a third antenna or more antennas, wherein said changeover switch means switches one of these antennas and the other end of said one coil for connection to a receiver side. 2. The antenna of claim 1, wherein the antenna is switchable.