JPH03192902A - Three-wave compatible antenna system - Google Patents

Abstract

PURPOSE:To send a signal of AM/EM broadcast to a receiver efficiently by connecting an AM broadcast use impedance conversion circuit and also connecting a matching circuit for FM broadcast to a base of a two-stage colinear array antenna. CONSTITUTION:A colinear array antenna 10 formed by stacking half wavelength dipole antennas 11 for an automobile radio telephone signal is provided, an AM broadcast impedance conversion circuit 21 and also an FM broadcast matching circuit 18 are connected to a base end 10a of the colinear array antenna 10. Then an AM broadcast signal and an EM broadcast signal outputted respectively from the impedance conversion circuit 21 and the matching circuit 18 are given to an AM/FM broadcast receiver 24 via a cable 23 and given to an automobile radio telephone set 17 via the two-stage colinear array antenna 10 and a cable 16. Thus, the AM/FM broadcast signal received by the antenna 10 is sent efficiently to the AM/FM broadcast receiver 24.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is directed to a three-wave antenna device that uses a single antenna as a reception antenna for AM broadcasting and FM broadcasting, and an antenna for transmitting and receiving car radio telephone signals. More specifically, the present invention relates to a three-wave antenna device that can satisfactorily receive AM and FM broadcasts using a collinear array antenna in which half-wavelength die-ball antennas for car radio telephone signals are stacked.

(Prior Art) As an antenna for an in-vehicle AM/FM broadcast receiver, as shown in Fig. 5, a rod antenna 1 having a length of about 1.0 to 1.4 m is telescopically attached to the roof of a car 2, etc. , from the base end of this rod antenna 1 to 8 AM/FM broadcast receivers 4 via a 75Ω or 50Ω coaxial cable 3.
FM broadcast signals are generated manually. In addition, in recent years, automobile radio telephones have been rapidly becoming popular, and as an antenna for this purpose, a two-stage collinear array antenna 5, which is numerically stacked in two stages of half-wavelength die-ball antennas for automobile radio telephone signals, is used for automobiles. A car radio telephone signal is input and output from the base end of the two-stage collinear array antenna 5 to the car radio telephone via a 75Ω or 50Ω coaxial cable.

(Problem to be solved by the invention '1fU) As mentioned above,
Conventionally, in order to install a car radio telephone in an Auto II 1.2, it was necessary to install a two-stage collinear array antenna 5 separately from the rod antenna 1 for AM and FM broadcasts, which caused problems with the appearance of the car and This is undesirable due to wind noise, etc., and the danger increases as the protrusion protrudes LH. Therefore, it may be possible to use the rod antenna 1, which has a length of about 1 m, also as an antenna for a car radio telephone. The length of about 1 m of the rod antenna 1 corresponds to approximately 1/4 wavelength of an FM broadcast signal, and is intended to cause antenna resonance and obtain a high antenna gain for FM broadcast.

Incidentally, it is desirable that the antenna as a protrusion of the automobile 2 be as short as possible. The reason for the stiffness is to make the exterior look neat, reduce wind noise, and prevent the long antenna from being accidentally damaged in garages, road structures, etc. Therefore, it is conceivable to conversely use the two-stage collinear array antenna 5 for a car radio telephone as an antenna for an AM/FM broadcast receiver. However, the two-stage collinear array antenna 5 for automobile radio telephones has a length of about 40 cm, and cannot resonate the FM broadcast signal.
As an antenna for receiving M broadcasting, the gain is significantly reduced. Furthermore, as an antenna for AM broadcasting, the shorter the length, the lower the signal strength that can be received. With that, automatic ILt!
#. Even if the two-stage collinear array antenna 5 for line telephones was to be used as an antenna for receiving AM/FM broadcasts with the same structure, there was a problem that it would not be practical.

The present invention was made in view of the above-mentioned circumstances, and improves the efficiency of transmitting AM/FM broadcast signals received by an antenna to an AM/FM broadcast receiver. It is an object of the present invention to provide a three-component common antenna device using a collinear array antenna for radio telephones and which can withstand practical use.

(Means for Solving the Problems) In order to achieve the above object, the three-component common antenna device of the present invention is a common antenna device for receiving AM broadcasts and FM broadcasts and for transmitting and receiving automobile radio telephone signals. A collinear array antenna is provided in which half-wavelength die-ball antennas for the car radio telephone signal are stacked, and an impedance conversion circuit for AM broadcasting is connected to the base end of the collinear array antenna, and a matching circuit for FM broadcasting is connected to the base end of the collinear array antenna. The AM broadcast signal and the FM broadcast signal respectively output from the impedance conversion circuit and the matching circuit are applied to the AM/FM broadcast receiver via a cable, and the automobile radio telephone signal is transmitted from the two-stage collinear array antenna to the cable. and is configured to provide information to a vehicle radiotelephone via the mobile radiotelephone.

(Function) At the base end of the collinear array antenna, the output impedance for AM broadcasting signals is almost infinite. Even if a 75Ω or 50Ω coaxial cable is connected to this base end, most of the AM broadcast signal will be reflected due to the mismatch.

Accordingly, in one aspect of the present invention, by connecting an impedance conversion circuit for AM broadcasting to the base end of the collinear array antenna, matching between the antenna and the cable can be obtained, and AM broadcasting signals can be efficiently transmitted to the receiver. Furthermore, although the output impedance for FM broadcast signals is not infinite, it is far from the impedance of a cable. Therefore, in one aspect of the present invention, by connecting a matching circuit for FM broadcasting to the base end of the collinear array antenna, matching between the antenna and the cable can be obtained, and the FM broadcasting signal can be efficiently transmitted to the receiver.

(Example) Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 4. FIG. 1 is a block circuit diagram of an embodiment of the five-wave common antenna device of the present invention, FIG. 2 is a circuit diagram of a specific example of FIG. 1, and FIG. FIG. 4 is a circuit configuration diagram for comparatively measuring the performance of the three-component antenna device according to the present invention using an auditory test method, and FIG. 4 is a circuit configuration diagram for comparing and measuring the performance of the present invention using a C/N ratio measuring method.

First, the configuration of the three-wave antenna device of the present invention will be explained based on FIG. In FIG. 1, a two-stage collinear array antenna 10 receives a car radio telephone signal (870 to 94
0MHz) approximately half wavelength die ball antenna I+, +1
are stacked in two stages via a phase inverting coil 12. And this two-stage collinear array antenna 1
A bandpass filter 13 for passing a car radio telephone signal and an FM broadcast (76 to 90MH)
, ) low pass or band pass filter 14 and AM broadcast (525 to 1605) 12)
A low-pass or band-pass filter 15 that passes the signal is connected to each. These filters +3.1
4.15 is for separating signals of each band. The automobile radio telephone signal that has passed through the filter 13 is outputted to the automobile radio telephone 17 via a coaxial cable 16 of 50Ω or the like. Further, the FM broadcast signal extracted by the FM broadcast filter 14 is amplified by a low noise amplifier 19 via a matching circuit 18. Then, the FM broadcast signal is again extracted from the amplified output of the low noise amplifier 19 by the band pass filter 20. moreover,
The AM broadcast signal extracted by the AM broadcast filter 15 is given to the low-pass filter 22 via the impedance conversion circuit 2I. Then, the AM broadcast signal extracted by the low-pass filter 22 and the FM broadcast signal extracted by the band-pass filter 20 are superimposed again.
The signal is manually inputted to an AM/FM broadcast receiver 24 via a coaxial cable 23 of 50Ω or the like. Note that filters 13, 14, 1
5, 20.22 and matching circuit 18 and low noise amplifier! 9
And the impedance conversion circuit 2I is housed in one metal housing 25, and this metal housing 25 is a two-stage collinear array antenna! It is fixedly arranged at the proximal end of 0.

Furthermore, the main parts of the three-wave antenna device of the present invention will be briefly explained based on FIG. In FIG. 2, circuit parts forming the circuit blocks shown in FIG. 1 are given the same reference numerals as in FIG. The matching circuit 18 for FM broadcasting includes the coil 3
It is formed by a π-type connection of 0,31,32. Also, A
The impedance conversion circuit 21 for M broadcasting includes a filter [
The AM broadcast signal extracted in step 5 is applied to the gate of a MOS field effect transistor 33, and the amplified AM broadcast signal is output from the drain. Here, the gate of the field effect transistor 33 has an extremely high input impedance, and can be matched with the output impedance of the two-stage collinear array antenna 10 for AM broadcasting signals. Further, the source of the field effect transistor 33 is grounded, and the drain is connected to the coaxial cable 22 by a low-pass filter 22 etc. connected to the subsequent stage with a low output impedance.
3.

The performance of the three-wave antenna device of the present invention having such a configuration will be described below. First, the three-wave common antenna device of the present invention uses a two-stage collinear array antenna 10 for car radio telephones as an antenna, and it goes without saying that it has the same performance as conventional devices for car radio telephone signals. be. Therefore, in order for the three-wave antenna device of the present invention to be useful, it is necessary that the device of the present invention is equivalent to or better than the conventional device using a rod antenna 1 with a length of about 1 m. performance must be obtained. In order to confirm this performance, the inventors conducted a hearing test and C/N ratio measurement.

First, as a hearing test method, as shown in FIG. 3(A), in the conventional device to be compared, the base end of a rod antenna l of approximately 1 m length is connected to an attenuator 41 via a 50Ω, 5 m coaxial cable 40. death.

This attenuator 41 is connected to an AM/FM broadcast receiver 43 via a 50Ω, 1 m coaxial cable 42. The apparatus of the present invention for AM broadcasting is shown in FIG. 3(B).
As shown, the base end l of the two-stage collinear array antenna 10
A test antenna is formed by connecting an impedance conversion circuit 21 to O, and its output end is connected to an attenuator 41 via a coaxial cable 40, and the structure is then configured in the same manner as shown in FIG. 3(A). Also.

The device of the present invention for FM broadcasting is applicable to No. 31271 (C
), a matching circuit 18 is connected to the base part 107 of the two-stage collinear array antenna lO to form a test antenna, and a low noise amplifier 19 is connected in series to the output end of the matching circuit 18.
The output end of this low noise amplifier 19 is connected to the coaxial cable 40.
The configuration will be similar to that shown in FIG. 3(A). In addition,
The AM/FM broadcast receiver 43 in FIG. 3(A) is
AM receiver 4] and FM receiver 4 in FIGS. 3(B) and (C) in comparison of M broadcasting and FM broadcasting, respectively.
Of course, it has the same performance as 3.

With this configuration, the volume of the AM/FM broadcast receiver 43 is set to the maximum, and the attenuator 41 gradually attenuates (the M signal). Compare the amount of attenuation as a measured value.

In AM broadcasting, 594,810,954.
When tuned to H2 at 1134.1242, attenuator 4! The amount of attenuation due to is 26,4,
10,13.11 dB, whereas the attenuation amount by the attenuator 41 in the device of the present invention is 38,11,2 dB.
It was 2.21.15 dB. Regardless of the frequency, the amount of attenuation by the attenuator 41 is greater with the device of the present invention, and in this hearing test, the three-component antenna device of the present invention was more efficient (receiving AM broadcast signals from AM/FM broadcasts). This shows that it can be transmitted to the machine 43 side.
In FM broadcasting, 77.1°80.0.86.3MH
2, the attenuation amount of attenuator 4I in the conventional device was 0.2.42 dB,
The amount of attenuation due to the attenuator in the device of the present invention is 7.1
It was 5°52dB. Therefore, in this hearing test method, even in FM broadcasting, the three-component antenna device of the present invention more efficiently transmits signals to the AM/FM broadcast receiver 43.
It shows that it can be transmitted to the other side.

In addition, as a C/N ratio measurement method, the conventional device used for comparison in receiving AM broadcasting is as shown in Fig. 4 (A). Preamplifier 4 with gain 30dB through 40
4, and connect the output end of this preamplifier 44 to 50Ω, 1
It is connected to a spectrum analyzer 45 via a coaxial cable 42 of m. The apparatus of the present invention is shown in FIG.
As shown in B), the impedance conversion circuit 21 is connected to the base end 10a of the two-stage collinear array antenna 1o to form a sample antenna, and its output end is connected to the preamplifier 44 via the coaxial cable 40. The configuration is similar to that shown in FIG. 4 (A). Note that the preamplifier 44 is provided to amplify the antenna noise so that the spectrum analyzer 45 can read the magnitude of the antenna noise, since the antenna noise is smaller than the human noise of the spectrum analyzer 45.

With this configuration, 594,810.95 in AM broadcasting
For the respective frequency signals of 4.1134.1242 MH, the C/N ratio by the spectrum analyzer 45 in the conventional device is 15.10, 20.19.2.
0 dB, whereas the C/N ratio in the device of the present invention was 25.9°19.23.18 dB. Therefore, in AM broadcasting, almost the same C/N ratio (!I) is achieved in all bands.

Furthermore, as a method for measuring the C/N ratio in receiving FM broadcasts, the conventional device to be compared uses a 50Ω coaxial cable connected to the base end of the approximately 1m rod antenna 1 using a 5m coaxial cable, as shown in Figure 4 (C). connected to the first amplifier 46 via 40;
The output end of this first amplifier 46 is connected to a preamplifier 44 with a gain of 30 dB, and the output end is connected to a preamplifier 44 with a gain of 50 Ω, tm
It is connected to a spectrum analyzer 45 via a coaxial cable 42 . The device of the present invention has a base end portion 10 of a two-stage collinear array antenna lO. is connected to the matching circuit 18 to form a test antenna, and its output end is connected to the first amplifier 46 via the coaxial cable 42, and the subsequent configuration is the same as that shown in FIG. 4(C).

With this configuration, 77.1°80.0,
86.3, the C of the conventional device for the H2 frequency signal
The C/N ratio was 11.13.56 dB, while the C/N ratio of the device of the present invention was 18.21.57 dB. Therefore, in FM broadcasting, performance has been improved in all bands.

In the above embodiment, the two-stage collinear array antenna 10 in which two half-wavelength die-ball antennas for car radio telephone signals are stacked is described as a three-component common antenna, but the antenna is not limited to this. A collinear array antenna in which a die ball antenna and a 1/4 wavelength die ball antenna are stacked may be used.

(Effects of the Invention) Since the three-liquid common antenna device of the present invention is configured as described above, it has the following effects.

Receives AM and FM broadcasts and transmits and receives car radio telephone signals with performance equivalent to or better than conventional equipment.
Can be shared with one antenna device. Furthermore, the length of the antenna is approximately 40 cm for a collinear array antenna for automobile radio telephones, which is less than half the length of a conventional rod antenna for receiving AM/FM broadcasts, which is approximately 1 m. . Therefore, if the three-component antenna device of the present invention is installed in an automobile, the appearance will be excellent, wind noise will be reduced, and the possibility of accidental damage to the antenna by a garage or road structure will be extremely reduced. Furthermore, while conventional systems require two antennas, one for receiving AM/FM broadcasts and one for transmitting/receiving car radio telephone signals, the present invention requires only one antenna, making the entire device inexpensive.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram of an embodiment of the three-component antenna device of the present invention, FIG. 2 is a circuit diagram of a specific example of FIG. 1, and FIG. FIG. 4 is a circuit configuration diagram for comparatively measuring the performance of a three-liquid common antenna device using an auditory test method; FIG. FIG. 5 is a diagram in which a conventional AM/FM broadcast receiving device and a vehicle radio telephone device are installed in a car. 10: Two-stage collinear array antenna, IO1 two base ends, 11: Half-wave die ball antenna, 16° 17: 2! : 24: 23: Coaxial cable, car radio telephone, 18: Matching circuit, impedance conversion circuit, AM/FM broadcast receiver.

Claims (1)

[Claims] A shared antenna device for receiving AM broadcasting and FM broadcasting and for transmitting and receiving automobile radio telephone signals, comprising a collinear array antenna in which half-wavelength die-ball antennas for the automobile radio telephone signals are stacked, and a base of the collinear array antenna. An impedance conversion circuit for AM broadcasting and a matching circuit for FM broadcasting are connected to the end, and the AM broadcasting signal and FM broadcasting signal respectively output from the impedance conversion circuit and matching circuit are connected to the AM broadcasting signal via the cable. / FM broadcast receiver, and a three-wave common antenna device characterized in that the collinear array antenna provides a car radio telephone signal to the car radio telephone via a cable.