JP2000174543A - Antenna system and automatic train controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna system where the directivity of a plane antenna is enhanced for both of radiation and incidence of a radio wave and to provide an automatic train controller mounted with the antenna system. SOLUTION: The antenna system consists of a plane antenna 10 that emits or receives a radio wave at a microwave band and a lens antenna 20 made of a dielectric material and placed on the plane antenna. The plane antenna 10 is formed on an insulation board 11 and they are contained in a vessel consisting of a box 30 and an upper cover 40. Preferably, the lens antenna 20 is formed to be a convex lens or a concaved lens by interposing a dielectric material between a curved face 21 swollen outward in the radio wave radiation direction or concaved in the direction of an aperture and a plane 22 opposed to the curved face 21. For example, the antenna system is built in a ground element of an automatic train controller and placed on a crosstie in a track and opposed the on-vehicle element in a passing train to emit a communication radio wave thereto, or the antenna system may be built in the on-vehicle element to receive a communication radio wave.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an antenna device suitable for a microstrip antenna or the like. In particular, the present invention relates to an antenna device suitable for an electronic tab that detects the position of a moving object by radio waves in a non-contact manner.

[0002]

2. Description of the Related Art In general, there is known an automatic train control system for the purpose of safe operation management of trains and accurate stop control. In this automatic train control system, in the track of each line section, a grounding element that is a communication means with the running train is installed, and is opposed to each grounding element, and is a response means for each grounding element. The upper child is mounted on each train. Each antenna device for mutually radiating or radiating radio waves is built in the ground child and the vehicle child.

According to this automatic train control system, when the vehicle child of each train passes on each ground child, various management information can be communicated with the passing train via both antenna devices. For example, the identification number of the train is notified from the upper child to the lower child, which train is passing, and the passage timing is determined, and based on the elapsed time after passing the upper child. Thus, it is possible to control the braking of the train up to the scheduled stop line thereafter.

[0004]

However, the above antenna device has the following problems. For example, in the above-mentioned train operation management, there is a case where it is desired to perform train detection with high accuracy. Therefore, in order to determine the passage timing of the vehicle child just above each ground child, a planar antenna is used for the antenna device, and a radio wave in the microwave band is radiated and incident in the vertical direction of the track laying surface. However, it is necessary to provide a certain distance from the ground child to the vehicle child, and the directivity at the time of radiation by the planar antenna is not sufficient. I was asked.

[0005] Further, with the distance from the ground child to the vehicle child, the radiated radio wave from the ground child spreads, and a part thereof cannot be incident on the planar antenna of the vehicle child. The strength of the radio wave decreases. For this reason, it is necessary to increase the surface area of the planar antenna of the vehicle body or to increase the degree of amplification of an incident radio wave, and it is difficult to reduce the size of the vehicle body and make it a simple circuit configuration. Elimination of problems was an important issue.

An object of the present invention is to provide an antenna device in which the directivity of a planar antenna is improved irrespective of radiation or incidence of radio waves.

[0007]

According to a first aspect of the present invention, there is provided a planar antenna provided on an insulating substrate surface for emitting a radiated radio wave or receiving an incident radio wave. It consists of a dielectric radio wave lens formed on the surface of the antenna.

According to the first aspect of the present invention, a radio wave in a microwave band is passed through a radio wave lens, and the radio wave is emitted to the outside while converging the radio wave in the dielectric, or the incoming radio wave is diverged in the dielectric. While making it incident on the planar antenna.

According to a second aspect of the present invention, there is provided a planar antenna for radiated radio waves provided on the insulating substrate surface, a dielectric convex lens type radio wave lens formed on the surface of the planar antenna, and an incident radio wave lens provided on the insulating substrate surface. It consists of a radio wave planar antenna and a dielectric concave lens type radio wave lens formed on the plane of the planar antenna. According to this, the radiated radio wave can be converged by the convex lens type radio wave lens, and the incident radio wave can be diverged by the concave lens type radio wave lens.

According to a third aspect of the present invention, there is provided an automatic train control device in which the antenna device according to the first or second aspect is incorporated in a ground child or a vehicle child. According to this, the position can be detected while converging or diverging the detection radio wave between the ground child and the vehicle child.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a sectional view illustrating an example of an antenna device according to the present invention. This antenna device 1
Is composed of a planar antenna 10 for radiating or entering microwave band radio waves and a radio wave lens 20 provided on the planar antenna 10. The planar antenna 10 is formed on an insulating substrate 11 surface. These are housed in a container consisting of the box 30 and the upper lid 40.

For example, in an automatic train control device, the antenna device 1 is used for position detection by a mobile identification device (for example, a microwave transponder) of a premises radio station or a specific low-power radio station. It is installed on paving stones, sleepers, etc., and emits detection radio waves facing the upper car of the passing train. Alternatively, the radio wave may be incorporated in the upper arm and attached to the lower part of the step of getting on and off the crew of the train, and the detection radio wave from the ground arm may be incident.

In addition, it may be used as an electronic tag for identifying a vehicle at a stop position of a parking lot, a tollgate on a highway, or the like. Or on the floor, or in the passageway,
It can be hung from above the aisle, and may be mounted on the vehicle itself.

The radiated radio wave or the incident radio wave is of a circular polarization, and interference by surrounding general radio waves is avoided. However, the additional circuit of the antenna device 1 is formed by using a vertical or horizontal linearly polarized wave. A simple configuration may be used. Hereinafter, the case of circular polarization will be mainly described.

FIG. 2 is a plan view of the antenna device shown in FIG. 1, showing a state in which an upper lid is removed from the container. The planar antenna 10 is formed by cutting a conductive metal foil into a circle suitable for circularly polarized waves and forming it on a substrate 11 by a known printed wiring technique, and is formed on two orthogonal axes intersecting at the center of the circle. Is provided with a feeding point (not shown).

The radio wave lens 20 has a curved surface 21 bulging outward in the direction of radio wave radiation and a flat surface 2 facing the curved surface 21.
2 is a convex lens type radio wave lens made of a dielectric formed into a convex lens shape sandwiched between the two. The plane 22 is made to face the opening surface of the flat antenna 10, and the optical axis of the convex lens is aligned with the center of the flat antenna 10. Besides this,
A concave lens type radio wave lens having a concave lens shape sandwiched between a curved surface 21 concaved inward toward the opening surface and a flat surface 22 may be used.

As the material of the radio wave lens 20, a material having high weather resistance and high environmental resistance is selected. Even when the ground antenna is installed outdoors and exposed to the outside air, the flat antenna 10 is protected from the wind, rain, snow and ice, sunshine and the like. It is desirable to use a synthetic or natural resin, rubber, or the like that can protect the resin and can be easily formed. As a result, the function of the radome that covers the planar antenna 10 can be provided, and the radome attached to a general outdoor antenna can be diverted for improving the directivity. For example, FRP (fiber reinforced resin) is desirable, and if it is PBT (polybutylene terephthalate), a grade that can increase the solvent resistance and chemical resistance to machine oil and the like and is more resistant to cracking can be selected.

In addition, if the relative permittivity Er1 of the microwave band radiated radio wave is 5 or less, the radiated radio wave is not excessively attenuated. Further, for example, even if the relative dielectric constant Er1 is less than 2.1, the use of ethylene tetrafluoride seems to increase the number of internal bubbles, making it difficult to maintain the mechanical strength of the convex lens shape. For this reason, the above-mentioned FRP having a relative dielectric constant of nominally 3.4 is preferable.

Further, the shape and size of the curved surface can be arbitrarily selected from a spherical surface, an ellipse, a parabolic surface, etc. based on a detection test of a radiated radio wave or an incident radio wave. The test conditions at that time include:
There are the average distance from the ground child to the vehicle child, the area of the planar antenna 10, the radiation intensity of the radio wave, the amount of attenuation of the transmitted radio wave by the adopted material, the detection sensitivity of the vehicle child, etc. Just set it.

A coaxial cable is guided from a transmitter (not shown) to the container, and the core wire at the end of the coaxial cable needs to be passed through a through hole of the substrate 11 and further connected to each feed point of the planar antenna 10. For this purpose, a concave portion 31 opened toward the substrate 11 is provided in the box 30 of the container.
It houses a connection component between the end of the coaxial cable and the substrate 11, an impedance matching circuit, and the like.

When the effect of the train body on radio waves is insufficient when the antenna device 1 is used as a vehicle upper body,
A ground plane having a sufficient area may be provided on the back surface of the substrate 11 opposite to the plane antenna 10. On the other hand, a ground child can be directly affected by the earth.
After assembling the antenna device 1 in the container, the lower end portion of the box 30 is fixed on the railroad tie through a fixture (not shown).

Steps 32 and 42 are provided on the upper edge of the box 30 and the lower edge of the upper lid 40 of the container, respectively, and the step 42 of the upper lid 40 is fitted into the step 32 of the box 30. To increase the degree of sealing and facilitate assembly of the container. As the material of the box 30 and the upper lid 40,
It is necessary to select a material that can withstand an external impact. In particular, the material of the box body 30 is to protect the electric components such as the flat antenna 10 and the substrate 11 from the external environment, so that the weather resistance and the environmental resistance It is desirable to select a material with a high level.

The upper lid 40 of the container is provided with a concave portion 41 opened toward the curved surface 21 of the above-described radio wave lens 20, and its shape is adjusted to the outer shape of the curved surface 21 of the radio wave lens 20.
The radio wave lens 20, the planar antenna 10 and the substrate 11 are formed so as not to be displaced in the container when 0 is put on the box 30.

As described above, the configuration in which the upper cover 40 is not necessarily provided as long as the radio wave lens can withstand displacement or an external impact. Further, in addition to the above, the radio wave lens 20 and the upper lid 40 may be integrally formed,
Thus, if the process of printing and wiring the planar antenna 10 on the substrate 11 is distinguished from the process of forming the container, manufacturing control can be easily performed. Next, the operation of the antenna device 1 will be described.

FIG. 3 is a view for explaining the convergence of radio waves by the radio wave lens shown in FIG. Since the radio wave lens 20 has a configuration in which the plane 22 is bonded to the opening surface of the planar antenna 10, the plane 22 is irradiated with radiated radio waves E1, E2, and E3 vertically, and the wave front W1 is moved with respect to the plane 22. You can think of them as being parallel. Therefore, each radiated radio wave E
When E1, E2, and E3 enter the radio wave lens 10, the phases thereof are uniformly transmitted according to the dielectric constant of the dielectric.
The light propagates through the radio wave lens 10 toward the curved surface 21.

Subsequently, when the radiated radio waves E1, E2 and E3 are emitted from the curved surface 21, the relative dielectric constant Er2 in the air is smaller than the relative dielectric constant Er1 of the dielectric substance. While propagating in the air while following the relative dielectric constant Er2. At this time, the radiated radio waves E1 and E3 incident on the peripheral edge of the radio wave lens 20 can be emitted into the air earlier than the radiated radio wave E2 along the optical axis of the radio wave lens 20. Until reaches the curved surface 21,
Each of the radiated radio waves E1 and E3 propagates in the air in advance.

In other words, each radiated radio wave E1,
The phase of the radiated radio wave E2 on the optical axis is relatively delayed as compared with E3. In other words, the radiated radio waves E1, E at the periphery and on the optical axis
Assuming two wavefronts W2 or W3 based on Huygens' principle by E2 and E3 and E2 (radio waves simultaneously emitted from the planar antenna 10), the respective wavefronts W2 and W3
3 is inclined inward toward the optical axis of the radio wave lens 20. At this time, since the traveling directions of the wavefronts W2 and W3 are the normal directions, the radiated radio waves E1, E2 and E3 converge inward and are formed at a predetermined focal position.

FIG. 4 is a diagram for explaining an example of use in which two types of the antenna devices shown in FIG. 1 are combined. Note that hatching is partially omitted. In this use example, the convex lens type radio wave lens 20 is built in the ground child on the sleeper, and the concave lens type radio wave lens 120 is built in the car upper mounted on the train.
Automatic train control is performed while radiating the detected radio waves from the ground child to the vehicle child.

Generally, at the periphery of the planar antenna 10,
Since the diffraction effect of the radio wave cannot be ignored, the electric field strength of the radiated radio wave weakens as the distance from the aperture increases. However, if the convex lens-shaped radio wave lens 20 is provided in front of the planar antenna 10 as described above, the diffraction component E at the peripheral edge thereof is obtained.
Radiated radio waves E12, E21, E3 including E11, E31
2 can be converged toward the upper child. That is,
In order to maintain the desired electric field strength even at a position away from the opening surface,
Position detection can be performed with high accuracy using such detection radio waves.

Further, instead of the above-described radio lens 20 having a convex lens shape, another radio lens 120 having a concave lens shape is provided on the planar antenna 10 in the same manner as the above-described vehicle upper arm. Then, from the ground child, each radiated radio wave E12, E
21 and E32 are radiated while being converged, and are incident on this another radio wave lens 120 to be diverged, while being received by the planar antenna 10 of the vehicle.

However, the converged radiation waves E11, E
It is known that the electric field intensities of E21 and E31 are generally not uniform in a plane orthogonal to the optical axis, and that the radiated radio waves E12 and E32 at the periphery thereof are stronger than the radiated radio wave E21 on the optical axis. . Further, depending on the outer shape of the curved surface of the radio wave lens 20, an edge aberration may occur, and as a result, a phase distortion may occur in the incident radio wave.

However, according to the above-described use example, even if the concave lens-shaped radio wave lens 120 built in the antenna device 100 of the vehicle body causes the aberration or the like caused by the convex lens-shaped radio wave lens 20, the aberration is corrected. , The radiated radio waves E12, E21, and E32 can be received by the planar antenna 10. Therefore, it is possible to receive the detected radio wave from the ground antenna without phase distortion.

FIG. 5 is a cross-sectional view illustrating an example of another antenna device according to the present invention, and FIG. 6 is a plan view of the antenna device, showing a state where an upper lid of the container is removed. This another antenna device 200
Then, instead of the disk-shaped planar antenna 10 described above,
Another planar antenna 21 having a shape obtained by cutting a metal foil into a rectangle
0, and another radio wave lens 220 formed in a semi-cylindrical convex lens shape is provided instead of the radio wave lens 20 formed of a rotating body having a convex lens-shaped cross section. The antenna device 1 is the same as the antenna device 1 except that an upper cover 240 having a concave portion 241 corresponding to the outer shape of the radio wave lens 220 is provided instead of the above-described upper cover 40.

This alternative antenna device 200 is suitable for the purpose of converging only linearly polarized radio waves in a direction orthogonal to the target axis of the semi-cylindrical shape in another radio wave lens 220. For example, if a target axis of a semi-cylindrical shape is provided along one of the vertical and horizontal directions parallel to one side of the rectangular plane of the planar antenna 210, the radio wave lens 220 can radiate radio waves from the planar antenna 210. By converging only in the left-right direction of the drawing, only diffraction and divergence of the radiated radio wave in the left-right direction can be suppressed.

A valley-shaped concave lens-shaped radio lens corresponding to the semicylindrical curved surface portion of another radio wave lens 220 is provided so as to face the another antenna device 200, and the concave lens-shaped radio wave lens is provided. Radiated radio waves from another antenna device 200 may be received. With this, the radiated radio wave can be made incident by diverging only the linearly polarized wave in the direction along the target axis of the valley shape. For example, the detected radio wave from the above-described ground element can be received without a phase difference.

Further, for example, the planar antenna 210 may be formed in a vertically long band shape, and the microstrip antenna may be formed on a printed circuit board. It can be realized efficiently. In addition, when forming the radio wave lens 220 and the upper lid 240, processing for forming the outer shape and the shape of the concave portion 241 becomes easy.

FIG. 7 is a cross-sectional view for explaining an example of still another antenna device according to the present invention, and FIG. 8 is a plan view of the same, showing a state where an upper lid of the container is removed. In this still another antenna device 300, the above-mentioned circular planar antenna 10 is
And a convex lens type radio wave lens 3
A parallel radio wave lens 320 in which a concave lens type radio wave lens 322 is arranged in addition to 21 is provided.

In addition, instead of the above-described upper lid 40, a concave portion 34 having a shape corresponding to the outer shape of the radio wave lens 320 is provided.
1 is provided, and two concave portions 31, 31 corresponding to the respective planar antennas 10, 10 are provided.
This is the same as the antenna device 1 except that another box body 330 having According to this, the antenna device 3
00 is built in the above-mentioned ground child and vehicle child, so that the detection radio wave can be mutually transmitted and received.

That is, for example, the ground antenna has a configuration in which a radiated radio wave is radiated from the planar antenna 10 on the left side of the drawing toward the vehicle upper child and received by the planar antenna 10 on the right side of the vehicle upper child drawing.
Therefore, according to this still another antenna device 300, in the mutual communication between the ground child and the vehicle child, both of the above-described effects resulting from the convergence and divergence of the radiated radio waves can be simultaneously realized.

In addition, a plurality of combinations of the planar antenna 10 and the radio wave lens 20 may be provided, and a configuration may be adopted in which the plurality of combinations collectively radiate radio waves or in which radio waves are incident. The directivity can be further improved by the collective configuration.

[0041]

According to the present invention, the following effects are exhibited by the above configuration. According to the first aspect, since the radiated radio wave is converged and the incident radio wave is diverged by the radio wave lens, the directivity of transmission or reception by the planar antenna can be improved. Therefore, even in transmission and reception at a certain distance, the electric field strength of the radiated radio wave can be sufficiently maintained.

According to the second aspect, since the incident radio wave is diverged simultaneously with the convergence of the radiated radio wave, if two antenna devices are opposed to each other, the influence of the convergence action and the divergence action on the detected radio wave can be offset.

According to the third aspect, since the distance between the ground child and the vehicle child is not hindered, it can be used for practical automatic train control.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of an antenna device according to the present invention.

FIG. 2 is a plan view of the antenna device shown in FIG. 1;

FIG. 3 is a view for explaining the radio wave convergence action of the radio wave lens shown in FIG. 1;

FIG. 4 is a view for explaining one usage example in which two types of the antenna devices shown in FIG. 1 are combined;

FIG. 5 is a cross-sectional view illustrating an example of another antenna device according to the present invention.

FIG. 6 is a plan view of the antenna device shown in FIG. 5;

FIG. 7 is a cross-sectional view illustrating an example of still another antenna device according to the present invention.

FIG. 8 is a plan view of the antenna device shown in FIG. 7;

[Explanation of symbols]

1,100,200,300 ... antenna device, 10,2
10: Planar antenna, 11, 311: Substrate, 20, 12
0, 220, 320 ... radio wave lens, 21 ... curved surface, 22 ...
Plane, 30, 330 ... box, 31, 41 ... recess, 32,
42 ... step, 40, 240, 340 ... top lid.

Claims (3)

[Claims] An antenna device comprising: a planar antenna provided on an insulating substrate surface for emitting a radiated radio wave or receiving an incident radio wave; and a dielectric radio wave lens formed on the surface of the planar antenna. 2. A planar antenna for radiated radio waves provided on an insulative substrate surface, a dielectric convex lens type radio wave lens formed on the surface of the planar antenna, and a plane for incident radio waves provided on an insulative substrate surface. An antenna device comprising an antenna and a dielectric concave lens type radio wave lens formed on the surface of the planar antenna. 3. An automatic train control device, wherein the antenna device according to claim 1 or 2 is built in a ground child or a vehicle child.