JPH06152489A - Antenna system for mobile object - Google Patents

Abstract

PURPOSE:To install an antenna at a mobile object without projecting the antenna from the mobile object or interrupting its field of vision. CONSTITUTION:Slit antennas 31-311 are constituted by providing plural slits 3 on a conductive outer panel 2 such as the the bonnet or top panel of an automobile 1 and attaching lead wires 5 on the both sides of the centers of slits 3. The outputs of respective slit antennas are individually communicated to a phase delay means composed of an optical fiber while respectively branching them into plural parts, and the output of the phase delay means is divided into plural groups so that the inside of the same group can be correspondent to mutually different plural slit antennas. The outputs are individually added by plural adding means provided for each group, and the maximum added result among the respective adding means is selected and outputted by a selecting means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile antenna device, and more particularly to a mobile antenna device suitable for installing an array antenna or the like.

[0002]

2. Description of the Related Art In a mobile radio device such as a car telephone or an in-vehicle radio, when the position or direction of the mobile body changes, the arrival direction of radio waves changes, so-called fading occurs and stable reception cannot be performed. For this reason, conventionally, a plurality of antennas having different directivities are installed in a moving body, the received electric field strengths of the respective antennas are compared, the strongest antenna is selected, and the output of the antenna is sent to the receiving unit in the subsequent stage. I was trying to guide (space diversity antenna device). However, since only one antenna is selected at any given time, the directivity of the selected antenna is not always optimal with respect to the arrival direction of radio waves.

On the other hand, a large number of antennas are installed in a moving body to form an array antenna, and the outputs of the respective antennas are combined while phase adjustment is performed to adapt to changes in the position or direction of the moving body. The inventor of the present application has proposed a diversity antenna device in which the antenna directivity (combined directivity) is changed so that high-sensitivity reception can always be performed irrespective of the arrival direction of a radio wave (Japanese Patent Application No. 4- 267309
(See Japanese Patent Publication).

This is because the outputs of the respective antennas constituting the array antenna are individually branched into a plurality of phase delay elements having a predetermined phase delay amount, and the same group corresponds to a plurality of different antennas. In this way, the output of the phase delay element is divided into a plurality of groups, and a plurality of adders provided for each group add individually, and the one with the largest addition result among the adders is selected. This is selected and output by. The phase delay amounts of the respective phase delay elements may be randomly different values, or may be the same value for the same antenna and may be a different value randomly between different antennas.

According to this apparatus, since the phase delay amount of each phase delay element may be fixed, it is possible to easily perform adaptive control of the antenna directivity in response to the change of the arrival direction of the radio wave.
A feature of the present invention is that it is possible to easily realize a diversity antenna device for a mobile body with higher sensitivity than before.

[0006]

By the way, in the array antenna, it is necessary to install a large number of antennas on the moving body. However, providing a large number of pole antennas has a high risk of breakage, and handling at the time of car washing is troublesome. In addition, it is not desirable from an aesthetic point of view. Further, providing a large number of printed antenna patterns on the windshield and the rear glass also has the disadvantage of obstructing the visual field of the occupant.

In view of the above, it is an object of the present invention to provide a moving body antenna device capable of installing an antenna on a moving body without protruding from the moving body or obstructing the field of view.
Further, it is possible to provide an antenna device that can be installed on a moving body without protruding from the moving body or obstructing the field of view, and that can always perform high-sensitivity reception regardless of the arrival direction of radio waves. Is. Another object is to provide an antenna device that can also perform transmission in the direction of arrival of radio waves at the time of reception.

[0008]

SUMMARY OF THE INVENTION In the present invention, the above-mentioned problems are solved by forming a plurality of slit antennas by providing gaps at a plurality of locations of a conductive enclosure of a moving body, and outputting the output of each slit antenna. The output of the phase delay means is divided into a plurality of groups so as to correspond to a plurality of different slit antennas in the same group while branching into a plurality of individual phase delay means, and a plurality of additions provided for each group This is achieved by individually adding by means, and by selecting among the adding means having the maximum addition result by the selecting means.

Further, it is achieved by providing a connecting means for connecting a transmission signal source to each phase delay means on the input side of the adding means selected by the selecting means, and enabling transmission from each slit antenna.

[0010]

A plurality of slit antennas are formed by providing gaps in a plurality of conductive enclosures, and the outputs of the slit antennas are branched into a plurality of phases and individually passed through the phase delay means. The output of the phase delay means is divided into a plurality of groups so as to correspond to a plurality of slit antennas different from each other, and the addition results are added individually by a plurality of addition means provided for each group. Select the largest one and output it. As a result, by combining each antenna output of the array antenna while adjusting the phase,
Even if it is an adaptive control type antenna device that can always receive with high sensitivity regardless of the change in the arrival direction of the radio wave,
Each antenna does not project outward from the moving body, and since it does not need to be provided on the glass, it does not obstruct the view.

Further, a transmission signal source is connected to each phase delay means on the input side of the addition means selected by the selection means, and transmission from each slit antenna is also possible. As a result, it becomes possible to perform transmission with directivity in the arrival direction of the radio wave at the time of reception.

Further, since the dielectric member material is fitted in the gap, it is possible to prevent rainwater and wind from entering the moving body, and the antenna gain can be easily adjusted.

Further, since the optical fiber cable is used as the phase delay means, the desired amount of phase delay can be easily obtained with low loss by changing the length and the refractive index of the optical fiber cable. There is also no risk of the phase delay means picking up noise in the moving body.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of a moving body antenna device according to a first embodiment of the present invention. In FIG. 1 (1), 1
Is a vehicle as an example of a moving body, and 3 _{1 to} 3 ₁₁ are slit antennas provided on an outer plate 2 which is an enclosure of the vehicle such as a hood and a top plate. In FIG. 1 (2), 4 is a slit (gap) formed in the enclosure, which has a linear or curved shape, and is formed in various locations and in various directions. The slit 4 may be formed by punching out a member forming the enclosure, or may be formed with a gap when the members forming the enclosure are bonded together, or the original gap of the enclosure may be used as it is. Reference numeral 5 is a lead wire for each slit antenna, which is connected to both sides of the central portion of the slit 4 by soldering or screwing.

Since the outer plate 2 such as the bonnet and the top plate is formed of a steel plate having high conductivity, when the slit 4 is formed in the steel plate, the vicinity of the slit functions equivalently as a bipole antenna. Therefore, an antenna received signal appears at one end of the lead wire 5. The slit 4 may be a gap, but a dielectric member may be fitted to increase the antenna gain. Further, by fitting a dielectric member or an optional member in the slit 4, it is possible to prevent rainwater or wind from entering.

Since the slit antennas 3 _{1 to} 3 ₁₁ are formed by the slits 4 provided on the outer plate 2 of the automobile, they do not project to the outside like the conventional vehicle-mounted pole antenna, and are broken or washed. Does not need to be handled with care, and it has almost no effect on the aesthetics of the car (if any member is fitted in the gap and painted in the same color as the outer panel, there will be no aesthetic problem. ).

FIG. 2 is a circuit diagram of the latter stage of the antenna.
In FIG. 2, the slit antenna is 4 in order to simplify the explanation.
Two cases are shown. Electrodes (E / O) 6 _{1 to} 6 ₄ are connected to the respective lead wires 5 and perform electro-optic conversion.
In addition, since it also serves as a distributor, it is a one-input multi-output type. Of course, as shown in FIG. 3, the lead wire 5 is connected to the one-input / multi-output distributor 14 to be divided into a plurality of systems.
The 1-input / 1-output electro-optical converter (E / O) 15 _ij may perform electro-optical conversion.

Returning to FIG. 2, 7 _{11 to} 7 ₁₃ , 7 _{21 to} 7 ₂₃ ,
7 _{31 to} 7 ₃₃ and 7 _{41 to} 7 ₄₃ are electro-optical converters 6 ₁ respectively.
It is an optical fiber cable connected in parallel to each other on the output side of ~ 6 ₄ and it delays the phase of the received signal of the antenna by a predetermined fixed phase delay amount according to the length and the refractive index and transmits it to a predetermined location in the vehicle. . According to the optical fiber cable, noise generated in the vehicle does not enter the optical signal during signal transmission.

The phase delay amounts of the respective optical fiber cables may all be randomly different values, or may be the same for the same slit antenna and may be different randomly for different slit antennas.

In FIG. 2, the outputs of the electro-optical converters 6 _{1 to} 6 ₄ are all distributed to three systems, but they may be distributed to two systems or four or more systems. electro - optical converter ₆₁ through ₄ need not be the same distribution number (there may be one that outputs only one system).

8₁₁~ 8₄₁, 8₁₂~ 8₄₂, 8₁₃~ 8₄₃Is each
Optical fiber cable 7₁₁, 7_{twenty one}, 7₃₁, 7₄₁,
7₁₂, 7_{twenty two}, 7₃₂, 7₄₂, 7₁₃, 7_{twenty three}, 7₃₃, 7₄₃Contact
The optical-electrical converter (O /
E), 9₁Is an optical-electrical converter 8₁₁, 8 _{twenty one}, 8₃₁, 8₄₁of
Adder for adding outputs, 9₂Is an optical-electrical converter 8₁₂, 8
_{twenty two}, 8 ₃₂, 8₄₂Adder for adding the outputs of 9₃Is light-electric
Air converter 8₁₃, 8_{twenty three}, 8₃₃, 8 ₄₃Add to add the output of
It is a vessel. If there is more than 4 lines from one slit antenna
If distributed above, the number of adders will be four or more.

Numeral 10 is a changeover switch for selectively selecting and outputting one of the outputs of the adders 9 _{1 to} 9 _3. The changeover switch is preferably an electronic type using a semiconductor switch, It may be mechanical. 11
Is a discrimination circuit for comparing the addition results of the adders 9 _{1 to} 9 ₃ and specifying the maximum level adder, and 12 is switched to the position corresponding to the maximum level adder specified by the determination circuit. A control circuit for switching the switch 10 is a receiver for performing a predetermined receiving operation such as RF amplification, IF conversion, IF amplification, and demodulation on the output of the switch 10.

Next, the operation of the above embodiment will be described. Na
Here, the phase delay amount of each optical fiber cable
Are all randomly different values.
Radio waves coming from a certain direction to the automobile 1 are
Antenna 3₁~ 3 _FourEach lead wire when received by
The received signal generated at the output end of₁Output A₁cosωt (1) Antenna 3₂Output A₂cos (ωt−θ₂) (2) Antenna 3₃Output A₃cos (ωt−θ₃) (3) Antenna 3_FourOutput A_Fourcos (ωt−θ_Four) ... (4). Where A₁~ A_FourIs the received signal amplitude,
θ₂~ Θ_FourIs the slit antenna 3₁Based on
It is the phase difference of other antennas.

The output e ₁ of the adder 9 ₁ is A ₁ cos (ωt−θ ₁₁ ) + A ₂ cos (ωt−θ ₂ −θ ₂₁ ) + A ₃ cos (ωt−θ ₃ −θ ₃₁ ) + A ₄ cos ( ωt−θ ₄ −θ ₄₁ ) (5) The output e ₂ of the adder 9 ₂ is A ₁ cos (ωt−θ ₁₂ ) + A ₂ cos (ωt−θ ₂ −θ ₂₂ ) + A ₃ cos (ωt _{-θ 3 -Θ 32) + a 4} cos (ωt-θ 4 -Θ 42) output e ₃ of (6) the adder 9 _{3, a 1 cos (ωt-Θ} 13) + a 2 cos (ωt- θ ₂ −θ ₂₃ ) + A ₃ cos (ωt−θ ₃ −θ ₃₃ ) + A ₄ cos (ωt−θ ₄ −θ ₄₃ ) ... (7) Θ _ij is the phase delay amount in the optical fiber cable 7 _ij .

From the equations (5) to (7), the adders 9 _{1 to} 9 are
₃ it can be seen that a difference is generated in the level of the output e ₁ to e _3, the output level of a certain one of the adder 9 _j It can be seen that the maximum in accordance with the radio wave arrival direction. If the direction of arrival of radio waves changes, the adder with the maximum output level also changes. In other words, when the output level of one adder 9 _j is the maximum, the output of the adder 9 _j is selected and the receiver 13
The directivity of the array antenna composed of the slit antennas 3 _{1 to} 3 ₄ can be made to match the current direction of arrival of the radio wave, and the direction of arrival of the radio wave changes due to the movement or change of the direction of the automobile 1. However, high-sensitivity reception will always be possible.

The output e ₁ to e ₃ of each of the adders 91 _to 93 ₃ is input to the determination circuit 11, level comparison is made, one adder 9 _j that is the maximum level is specified. The determination result of the determination circuit 11 is output to the control circuit 12, and the control circuit 12 switches to the position of the adder 9 _j which is the maximum level specified by the determination circuit 11
Switched 0, directs the output e _j of the adder 9 _j to the receiver 13. As a result, regardless of the movement or change in the direction of the automobile 1, it is possible to always receive with high sensitivity and stability.

FIG. 4 is a circuit diagram of the mobile unit antenna apparatus according to the second embodiment of the present invention with a part thereof omitted. In addition,
In FIG. 4, only the system related to the adder 9 ₁ is shown,
The other adders have the same configuration. The same components as those in FIG. 1 are designated by the same reference numerals. First
In the embodiment, only reception is performed, whereas in the second embodiment, transmission is also possible.

In FIG. 4, 16 is a transmitter as a transmission signal source, 17 is a changeover switch which selectively divides the output of the transmission circuit into three systems, and also has a neutral position. Reference numeral 18 ₁ is an electro-optical converter (E / O) provided corresponding to the adder 9 ₁ , and here, 1 also functions as a distributor.
It is a type with 4 inputs and 4 outputs. Of course, as in Figure 3,
It is also possible to provide a four-system distributor for each position of the changeover switch and a one-input one-output type electro-optical converter for each system.

19_11,19_{twenty one}, 19₃₁, 19₄₁Is electricity
Optical converter 18₁Is an optical connector to which each output side of
Optical fiber cable 7 for each optical connector₁₁，
7_{twenty one}, 7 ₃₁, 7₄₁One end side of is connected individually. light
Connector 19₁₁~ 19₄₁The optical-electrical converter 8₁₁~ 8
₄₁Is also connected. Other positive of changeover switch 17
The options are similarly configured. Electricity-
Optical converter 18₁Each output and optical connector 19_11,19_{twenty one}，
19₃₁, 19₄₁With a short distance fiber optic cable between
Although they are connected, they must all have the same length and refractive index.
It Similarly, the optical connector 19_11,19_{twenty one}, 19₃₁, 19
₄₁And optical-electrical converter 8₁₁~ 8₄₁Each optical fiber connecting between
The iber cables also have the same length and refractive index.

Reference numerals 20 _11, 20 ₁₂ and 20 ₁₃ are optical connectors to which the other ends of the optical fiber cables 7 ₁₁ , 7 ₁₂ and 7 ₁₃ are individually connected, and 21 _11, 21 ₁₂ and 21 ₁₃ are connected to the respective optical connectors. Optical-electrical converter (O / E), which can
Electrical conversion is done. Optical connector 20 _11, 20 ₁₂ , 20
_An electro-optical converter 6 ₁ is also connected to ₁₃ . Optical connectors 20 _11, 20 ₁₂ , 20 ₁₃ and optical-electrical converter 21 _11,
21 ₁₂ and 21 ₁₃ are connected with a short-distance optical fiber cable, but both have the same length and refractive index. Similarly, the optical connector 20 _11, 20 _12, 20 ₁₃ and the light -
Each optical fiber cable connecting between the electric converters 6 ₁ has the same length and refractive index. The optical connectors 19 and 20 are
It is provided to enable transmission of optical signals in both directions with a single optical fiber cable.

Reference numeral 22 ₁ denotes a power amplifier which also functions as an adder, and 23
Reference numeral ₁ denotes a transmission / reception demultiplexer, which outputs the signal received by the slit antenna 3 ₁ to the electro-optical converter 6 ₁ or outputs the output of the power amplifier 22 ₁ to the slit antenna 3 ₁ . This is for using one slit antenna 3 ₁ for both transmission and reception.

The control circuit 12A has a built-in memory (not shown) for storing the adder having the maximum output level specified by the discrimination circuit 11, and at the time of reception, the first circuit described above is used.
The same operation as that of the embodiment is performed, and the adder having the maximum output level specified by the determination circuit 11 is stored. On the other hand, at the time of transmission, it has a function of switching the changeover switch 17 to the position corresponding to the adder stored last at the time of reception immediately before.

Next, the operation of the second embodiment will be described. When the reception / transmission mode signal indicates the reception mode, the control circuit 12A switches to the position corresponding to the adder having the maximum output level specified by the discrimination circuit 11 as in the first embodiment. 10 is switched to output the output of the adder to the receiver 13. At this time, each time the adder specified by the determination circuit 11 changes, the data specifying the adder is updated and registered in the memory. Further, by switching the changeover switch 17 on the transmitting side to the neutral position, unnecessary radiation is prevented from being emitted from the slit antenna or the like.

At the time of reception, for example, the reception signal of the slit antenna 3 ₁ is transmitted via the transmission / reception demultiplexer 23 ₁ , the electro-optical converter 6 ₁ and the optical connectors 20 _{11 to} 20 ₁₃ to the optical fiber cable 7 ₁₁ to. Guided to 7 ₁₃ . Further, the optical signal transmitted through the optical fiber cable 7 _{11-7 41} via the optical connector 19 _{11-19 41} each light - is guided to electrical converter 8 _{11-8 41.}

On the other hand, when the reception / transmission mode signal is changed to the transmission mode, the control circuit 12A switches the changeover switch 17 to the position of the adder according to the data specifying the latest adder registered in the memory. . Here, it is assumed that the adder 9 ₁ has been specified. In this case, the transmission signal output from the transmitter 16 is transmitted via the changeover switch 17 to the four optical systems by the electro-optical converter 18 ₁ corresponding to the input side of the adder whose output has been selected at the time of reception. After being converted into a signal, it is guided to the optical fiber cables 7 _{11 to} 7 ₄₁ via the optical connectors 19 _{11 to} 19 ₄₁ .

Among them, the signal transmitted through the optical fiber cable 7 ₁₁ is guided to the optical-electrical converter 21 ₁₁ via the optical connector 20 ₁₁ . And this optical-electrical converter 21
After being converted into an electric signal in ₁₁ , the power is amplified in the power amplifier 22 ₁ , output to the slit antenna 3 ₁ via the duplexer 23 ₁ , and radiated to the outside. The signals transmitted through the other optical fiber cables 7 ₂₁ , 7 ₃₁ , and 7 ₄₁ are also processed in the same manner, and are radiated to the outside from the slit antennas 3 _{2 to} 3 ₄ . At this time, radio waves are emitted with the same directivity as that at the time of reception due to the reciprocity at the time of reception and transmission, so that it is possible to give directivity to the direction of arrival of the radio waves at the time of reception immediately before.

In FIG. 4, one optical fiber cable 7 _ij is used to transmit an optical signal in both directions, but two optical fiber cables having the same phase delay amount can be used.
You may make it use it differently at the time of reception and transmission. Also,
A power amplifier 22 is provided separately from the opto-electric converter 21,
The opto-electric converter may have a power amplification function.

In each of the above embodiments, the optical fiber cable is used as the phase delay means, but a phase delay line such as a distributed constant circuit may be used. In this case, the length of the phase delay line should be adjusted. Thus, a predetermined amount of phase delay can be obtained. When using a phase delay line, an electro-optical converter,
Optical-related components such as an optical-electrical converter and an optical connector are unnecessary, and instead, appropriate electrical components such as a distributor and a combiner are used. Further, if the shield type phase delay line is used, it is possible to prevent noise generated in the moving body from entering. Furthermore, in the second embodiment,
When using a phase delay line, power amplification can be performed in the transmitter. The moving body is not limited to an automobile, but may be another type such as a train or an airplane.

[0039]

As described above, according to the present invention, a plurality of slit antennas are formed by providing gaps at a plurality of locations in a conductive enclosure, and the outputs of each slit antenna are individually branched while being divided into a plurality of outputs. Through the phase delay means, the output of the phase delay means is divided into a plurality of groups so as to correspond to a plurality of slit antennas different from each other in the same group, and added individually by a plurality of addition means provided for each group, In each addition means,
Since it is configured to select and output the one with the maximum addition result, by combining each antenna output of the array antenna while adjusting the phase, regardless of the change of the arrival direction of the radio wave, high sensitivity is always obtained. Even in the adaptive control type antenna device capable of receiving, each antenna does not project outward from the moving body, and since it does not need to be provided on the glass, it does not obstruct the view.

Further, since the transmission signal source is connected to each phase delay means on the input side of the addition means selected by the selection means and the transmission from each slit antenna is also possible, the arrival of the radio wave at the time of reception It becomes possible to transmit with directivity in the direction.

Further, since the dielectric member is fitted in the gap, it is possible to prevent rainwater and wind from entering the moving body, and the antenna gain can be easily adjusted.

Further, since the optical fiber cable is used as the phase delay means, the desired phase delay amount can be easily obtained with low loss by changing the length and the refractive index of the optical fiber cable. There is also no risk of the phase delay means picking up noise in the moving body.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an antenna device according to a first embodiment of the present invention.

FIG. 2 is a circuit configuration diagram of the latter stage of the antenna.

FIG. 3 is a partial configuration diagram of a modification of FIG.

FIG. 4 is a configuration diagram in which a part of the antenna device according to the second embodiment of the present invention is omitted.

[Explanation of symbols]

1 Automotive 2 Outer plate 3 _{1 to} 3 ₉ Slit antenna 4 Slit 6 _{1 to} 6 ₃ , 15 _i1 to 15 _i3 , 18 ₁ Electro-optical converter 7 _{11 to} 7 ₁₃ , 7 _{21 to} 7 ₂₃ , 7 _{31 to} 7 ₃₃ , 7 _{41 to} 7 ₄₃ Optical fiber cable 8 ₁₁ to 8 ₁₃ , 8 ₂₁ to 8 ₂₃ , 8 ₃₁ to 8 ₃₃ , 8 ₄₁ to 8 ₄₃ , 2
1 _{11 to} 21 ₁₃ Electric-optical converter 9 _{1 to} 9 ₃ Adder 10, 17 Changeover switch 11 Discrimination circuit 12, 12A Control circuit 19 ₁₁ -19 ₄₁ , 20 ₁₁ -20 ₁₃ Optical connector

Claims (4)

[Claims] 1. A plurality of slit antennas are formed by providing gaps in a plurality of conductive enclosures of a moving body, and the outputs of the slit antennas are individually branched to a plurality of channels and passed through the phase delay means individually. , The output of the phase delay means is divided into a plurality of groups so as to correspond to a plurality of slit antennas different from each other in the same group,
It is characterized in that a plurality of adding means provided for each group are individually added, and the one having the maximum addition result among the adding means is selected and outputted by the selecting means. Antenna device for mobile. 2. The antenna device for a moving body according to claim 1, wherein a dielectric member is fitted in the gap. 3. A connection means for connecting a transmission signal source to each phase delay means on the input side of the addition means selected by the selection means, and transmission from each slit antenna is also possible. The antenna device for a mobile body according to claim 1. 4. The antenna device for a mobile object according to claim 1, wherein an optical fiber cable is used as the phase delay means.