JP2003178341A - Etc antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a wrong communication in an ETC antenna to be set in a form for radiating electromagnetic wave from the roof of a tollhouse to a road by allowing the limitation and control of the radiating range of electromagnetic wave to prevent the direct leak of the electromagnetic wave to another vehicle. <P>SOLUTION: In the gate of the tollhouse comprising the roof 2 set above the road 5 in a vehicle advancing direction (lane direction) and lateral islands 7 and 8 for partitioning a passage to regulate the passing width of vehicles, a plate antenna 1 is supported on the lower side of the roof 2 through a support 6 and set in a form suspended from the roof 2 side. Sheet-like radio absorbers 3 and 4 having prescribed width and height in the advancing direction of the road 5 are suspended from the ceiling, and arranged so as to laterally (laterally and longitudinally) nip the electromagnetic wave radiated from the antenna as barrier walls for regulating the radiating range. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna (referred to as "ETC antenna") for wireless communication with a vehicle in an automatic toll collection system (also referred to as "ETC") for a toll road, etc. The present invention relates to an ETC antenna installed on a roof-like structure (referred to as "roof").

[0002]

2. Description of the Related Art Automatic toll collection system (ETC: electr
onic toll collection system) is a system that automatically collects and deducts toll charges by wireless between an on-board device such as an in-vehicle computer installed in a car at the tollgate and an antenna installed at the tollgate. The time required to pass through the gate because it is possible to go in and out of toll roads such as expressways while the vehicle is running at the tollgate without stopping because the bar at the tollgate automatically opens and closes every time a car passes by. Is expected to be significantly shortened, and the effects of eliminating traffic congestion and reducing exhaust gas are expected.

FIG. 8 is a diagram showing a structure of a conventional ETC antenna at a tollgate. This figure is a view showing the arrangement of the gate and the antenna 1A of the conventional tollgate viewed from the approaching direction of the vehicle. The antenna 1A and the antenna 1A are installed by being supported by the antenna support 6A from the roof 2A of the tollgate. It is composed of islands 7A and 8A on the left and right of a partition provided on the road through which the vehicle passes. The electromagnetic wave radiated from the antenna 1A irradiates the lower road 5A and enables the toll collection process by wireless communication with a passing vehicle. However, such an ETC antenna arrangement has a drawback that electromagnetic waves leak to other lanes such as outside the vehicle island.

FIG. 9 is a diagram showing an example in which a radio wave absorber is installed at the gate of a tollgate, FIG. 9 (a) is a sectional view in the passage direction of the gate, and FIG. 9 (b) is a perspective view ( JP 2001
-217645). Corresponding to the roadside antenna 4B installed on the bottom surface of the roof 2B of the gate of the tollgate 1B supported by the four pillars 3B, the two pillars 3B arranged on one side in the width direction of the road 6B. Side plates 5B are respectively provided between the upper parts and between the upper parts of the two columns 3B arranged on the other side in the width direction of the road 6B, and at least the lower surface of the roof portion and at least the inner inner surface of the side plate 5B. A radio wave absorption panel 7B is provided on one side so that radio waves radiated from the roadside antenna 4B are multiple-reflected between the roadside and the side plate 5B.
It is intended to prevent reflection on the inner surface of the.

[0005]

The conventional ET shown in FIG.
In the C system, the irradiation range of the electromagnetic wave from the antenna to the passage of the vehicle is determined by the directivity characteristic of the antenna. Generally, the directivity is controlled so that the electromagnetic wave is emitted only to the vehicle or passage that passes below. However, it is difficult to prevent the electromagnetic waves from leaking to other lanes such as outside the vehicle island. Further, in the roadside antenna of the gate shown in FIG. 9, the side plate inner surface between the upper portions of the two columns 2B of the columns of the gate 1B corresponding to the road width,
A radio wave absorption panel 7B is provided on the lower surface of the roof to prevent the effects of multiple reflections and reflections from the side plates 5B. The range of direct waves emitted from the roadside antenna 4B is considered to be determined by the characteristics of the antenna and is wide. When using an antenna having a beam width, it is impossible to limit or control the irradiation range.

As a result, leakage to the adjacent lane due to the direct wave radiated from the antenna causes erroneous communication with a vehicle or the like passing through the adjacent gate, and the ETC system malfunctions. However, there is a problem in that there is a serious system defect that causes the accident such as the traffic of the vehicle being blocked due to the bar not opening and contact with the following vehicle. (Purpose) An object of the present invention relates to an ETC antenna that is installed in the form of irradiating electromagnetic waves to the road of a tollgate, limits the irradiation range of the electromagnetic waves, prevents the electromagnetic waves from leaking to other vehicles, and causes erroneous communication. It is to provide an ETC antenna that reduces the noise.

Another object of the present invention relates to an ETC antenna installed in the form of irradiating an electromagnetic wave from the roof of a tollgate to a road, which makes it possible to control the irradiation range of the electromagnetic wave and cause the electromagnetic wave to leak to another vehicle. Another object of the present invention is to provide an ETC antenna that prevents the occurrence of noise and reduces erroneous communication.

[0008]

The ETC antenna of the present invention is an ETC antenna at a tollgate for automatic toll collection, with the antenna installed above the passage of the vehicle and the vehicle on both sides of the antenna. And a radio wave shield for preventing the leakage of direct electromagnetic waves to vehicles in adjacent lanes installed in the traveling direction. Further, a radio wave shield that is provided in front of and behind the antenna in the traveling direction of the vehicle to prevent electromagnetic waves from leaking to a following vehicle.

Further, in each of the above inventions, the antenna and the radio wave shield are installed under a roof of a tollgate, or are installed via a slide mechanism or a hinge. The radio wave shield is installed from below the roof of a toll gate via a supporter, the radio wave shield is installed on a side surface of the supporter or the antenna, and the radio wave shield is It is characterized in that it is installed via a supporter or the antenna and a lifting mechanism. (Function) Regarding the ETC antenna installed in the form of irradiating the road from the lower part of the roof of the tollgate, the electromagnetic wave absorber or the metal shielding plate that shields the electromagnetic wave is installed on the left and right (and the front and back) of the antenna, Limit or control irradiation range
To prevent the direct wave of radio waves from leaking to other vehicles and reduce erroneous communication.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the ETC antenna of the present invention will be described with reference to the drawings. (First Embodiment) FIG. 1 is a diagram showing a configuration of an ETC antenna in an automatic fee collection system according to the present embodiment. This figure is a front view of the tollgate as seen from the approaching direction of the vehicle, and the ETC antenna of the present embodiment is an example installed under the roof (ceiling or the like) of the tollgate.

(Description of Configuration) In the present embodiment, a roof 2 installed on an upper portion of a road 5 in the traveling direction of the vehicle (lane direction), and left and right islands 7 partitioning a passage defining a passage width of the vehicle, In the gate of the toll gate, which is composed of 8 and 8, the antenna 1 is supported on the lower side of the roof 2 via an antenna support (support) 6 and is installed so as to hang from the roof 2 side. The antenna 1 of the present embodiment shows an example configured by a planar antenna, and a plate-shaped electromagnetic wave absorber 3 having a predetermined width and height in the traveling direction of the road 5 from the ceiling is provided in the vicinity of the antenna 1. Barrier (shielding plate) that hangs 4 and defines the irradiation range of electromagnetic waves radiated from the flat plate antenna
Are arranged so as to be sandwiched from the left and right. The electromagnetic wave absorbers 3 and 4 are installed as barriers on the lower side of the roof 2.

The antenna 1 has a radiation surface of the radio waves of the antenna arranged in parallel to the road surface so that the radiated radio waves irradiate the road 5 of the gate, and is automatic for charging a toll for a passing vehicle. It communicates with the in-vehicle device for the toll collection system. Although only a single gate is shown in the figure, a plurality of gates having the same configuration are arranged adjacent to each other on the road, including the upper and lower lines, or are arranged with a predetermined number of gates.

(Explanation of Operation) Antenna 1 of this embodiment
Irradiates electromagnetic waves toward the lower part of the tollgate with a predetermined directivity characteristic. By using a flat plate antenna as the antenna 1, directivity can be formed mainly on the inside of the islands 7 and 8 so that an effective electromagnetic field strength can be obtained. The side lobes also irradiate electromagnetic waves to the passages of adjacent gates beyond the islands 7 and 8, causing interference such as ETC communication with a vehicle passing through the adjacent gates, which causes malfunction of the ETC system.

In the present embodiment, flat plate-shaped electromagnetic wave absorbers 3 and 4 having a predetermined width and a predetermined height are arranged as an electromagnetic wave barrier so as to sandwich the antenna in parallel with the traveling direction of the vehicle and radiate from the antenna 1. Since it effectively absorbs electromagnetic waves that spread to the left and right of the traffic direction of the vehicle, it is possible that the radiated electromagnetic waves spread beyond the width of the passages partitioned by the islands 7 and 8 and leak and affect the passages of other gates. It can be prevented.

In this way, since the barriers of the electromagnetic wave absorbers are installed on the left and right sides of the ETC antenna 1 on the lower surface of the roof so as to be fixed to the roof, the irradiation range of the antenna can be limited and the antenna outside the island can be restricted. Erroneous communication due to leakage to another lane can be reduced, only communication with a vehicle passing under the ETC antenna 1 can be performed, and erroneous charging operation can be prevented.

In the above embodiment, an example in which the spread of the electromagnetic waves radiated from the antenna 1 in the vehicle width direction is limited has been described. However, the malfunction of the ETC operation is caused by a plurality of vehicles using the same gate approaching each other and passing therethrough. The present invention can also occur in the case where
Can also be applied. (Second Embodiment) FIG. 2 is a view showing an embodiment in which a radio wave absorber is provided in the lane direction. The figure shows the toll booth from the side. In this embodiment, with respect to the antenna 1,
This is an example in which plate-shaped electromagnetic wave absorbers 5 and 6 in a direction perpendicular to the traffic direction (vehicle width direction) are fixedly installed before and after the traffic direction of the vehicle.

In the present embodiment, a desired directivity direction is realized by inclining the radiation surface of the ETC antenna 1 with respect to the road surface by a predetermined angle in the traveling direction of the vehicle, and the electromagnetic wave absorbers 5 and 6 are provided in the vehicle. It is configured to hang down in the front-back direction of the traveling direction and adjust the length in the hanging direction to control the irradiation range of electromagnetic waves in the traveling direction with respect to the vehicle. In the case of this embodiment, by installing the front and rear in the lane direction,
It is possible to prevent interference between the ETC antenna 1 and the front and rear vehicles, and reduce erroneous communication. Further, as another example of the present embodiment, by combining with the embodiment shown in FIG. 1, it is possible to configure the radio wave absorbers to be installed in both the lane direction and the vehicle width direction. In this case, needless to say, it is possible to prevent erroneous communication with the following vehicle in addition to the vehicle in the adjacent lane.

In the above-mentioned embodiment, the barrier of the electromagnetic wave absorber against electromagnetic waves is attached to the roof. However, instead of directly attaching the electromagnetic wave absorber to the lower surface of the roof, the antenna as shown in FIG. 3 is used. It can be a structure attached to the support 6 for supporting.

(Third Embodiment) FIG. 3 is a view showing an embodiment in which a radio wave absorber is attached via a support. Each of the radio wave absorbers 3 and 4 has a hook-like (L-shaped) cross section in a direction perpendicular to the traveling direction of the vehicle (vehicle width direction), and has a predetermined length in the traveling direction and a predetermined height in the hanging direction. It has a plate shape. In addition, a similar electromagnetic wave absorber in the hanging direction is provided before and after the traveling direction, and a box shape having an integrated lower opening is provided, and a shape and structure in which the support 6 penetrates and supports the center of the bottom surface thereof. Can be In this case, the height of the radio wave absorber in the front-rear direction can be set to different dimensions as shown in FIG. 3, depending on the setting of the irradiation range.

FIG. 4 is a diagram showing an embodiment in which the electromagnetic wave absorber is attached to the side surface of the antenna body instead of being attached to the support. In this example, it can be attached by the above-described configuration described with reference to FIG. 3 so as to be parallel to the traveling direction or cover all directions.

Next, at the toll gate, an ETC system installed gate and a non-installed gate may coexist, and the influence on the electromagnetic waves on the side of the road, including the island shape of the passage and the installation status of equipment, etc. It is necessary to control the irradiation range of electromagnetic waves in accordance with the situation, etc.

(Fourth Embodiment) FIG. 5 is a diagram showing an embodiment in which the irradiation range of electromagnetic waves can be controlled by a radio wave absorber. ETC antenna 1 mounted on roof 2
Slide mechanisms 9 and 10 are provided on the left and right (or left and right front and back), and the electromagnetic wave absorbers 3 and 4 are installed on the movable parts of the slide mechanisms. By moving the movable part of the slide with respect to the antenna 1, the radio wave absorbers 3 in the traveling direction of the vehicle (or in the traveling direction and the direction perpendicular thereto),
4 is moved to control the irradiation range of the electromagnetic wave emitted from the antenna 1.

FIG. 6 is a diagram showing another embodiment in which the irradiation range of electromagnetic waves can be controlled. One side of the hinges 10 and 11 which can be pivoted on the left and right (or right and left and front) of the ETC antenna 1 attached to the roof 2 is fixed, and the other side of the hinge is the upper end of the inner or outer surface of the plate-shaped electromagnetic wave absorber. To fix. By rotating (rotating) the other side of the hinge and rotating the radio wave absorber with respect to the antenna 1, the radio wave absorbers 3 and 4 are tilted in the traveling direction of the vehicle (or the traveling direction and the direction orthogonal thereto). Thereby, the irradiation range of the electromagnetic wave radiated from the antenna 1 is controlled.

(Fifth Embodiment) FIG. 7 is a diagram showing still another embodiment in which the irradiation range of electromagnetic waves can be controlled. In the ETC antenna shown in FIGS. 3 and 4, the electromagnetic wave absorber is not fixedly coupled to the support 6 or the antenna 1,
The radio wave absorber is installed on the support 6 or the antenna 1 through the vertical elevating mechanisms 13 and 14, and the radio wave absorber is moved up and down to control the irradiation range.

In the above-described embodiments, the structure in which the irradiation range of the electromagnetic wave is defined and controlled by the barrier using the electromagnetic wave absorber is shown, but the electromagnetic wave absorber is partially or wholly composed of a metal plate or a wire mesh. It is possible. In addition, it goes without saying that the electromagnetic wave absorber that can be moved can be controlled remotely by using an electric mechanism instead of the manual mechanism. In addition, an ET equipped with the radio wave absorber of the present invention
The installation location of the C antenna has been explained in the example of the tollgate, but it can be used for poles such as streetlights and traffic lights, overpass structures such as overpasses and pedestrian bridges, and wall-shaped structures such as soundproof walls. It can be installed.

[0026]

According to the present invention, since radio wave shields such as radio wave absorbers for preventing direct wave leakage of electromagnetic waves in the traveling direction of the vehicle are provided on both sides of the antenna installed in the upper part of the passage of the vehicle, Even if the beam width of the antenna is wide, direct waves of electromagnetic waves can be effectively shielded, the irradiation range of electromagnetic waves can be appropriately limited, and leakage to other vehicles can be prevented. is there.

Further, by installing the radio wave shields in front of and behind the antenna in the traveling direction of the vehicle, it is possible to prevent the direct wave of electromagnetic waves from leaking to the following vehicle.

Further, since the radio wave shield is directly installed on the antenna supporter or the antenna, it is possible to surely limit the irradiation range of the electromagnetic wave, and when it is installed via the elevating mechanism, the irradiation range of the electromagnetic wave. Can be easily adjusted and controlled.

Further, by installing the radio wave shield under the roof of the tollgate via a slide mechanism or a hinge, it is possible to control the irradiation range of electromagnetic waves to the left, right, front and back in the lane direction asymmetrically. .

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of an ETC antenna of the present invention.

FIG. 2 is a diagram showing an embodiment in which a radio wave absorber is installed in a front-rear direction of a vehicle.

FIG. 3 is a diagram showing an embodiment in which a radio wave absorber is installed on a support of an antenna.

FIG. 4 is a diagram showing an embodiment in which a radio wave absorber is installed on the antenna itself.

FIG. 5 is a diagram showing an embodiment in which a radio wave absorber is installed by a slide mechanism.

FIG. 6 is a diagram showing an embodiment in which a radio wave absorber is installed by a hinge.

FIG. 7 is a diagram showing an embodiment in which the irradiation range of electromagnetic waves can be controlled.

FIG. 8 is a diagram showing a conventional ETC antenna.

FIG. 9 is a diagram showing another example of a conventional ETC antenna.

[Explanation of symbols]

1 antenna 2 roof 3, 4 radio wave absorber 5 roads 6 antenna support 7, 8 islands 9,10 slide mechanism 11 and 12 hinges 13, 14 Radio wave absorber lifting mechanism

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // G08G 1/09 G08G 1/09 F

Claims (9)

[Claims] 1. An ETC antenna at a tollgate for automatic toll collection for an antenna installed above a passageway of a vehicle and a vehicle on an adjacent lane installed on both sides of the antenna in the traveling direction of the vehicle. An ETC antenna including: a radio wave shield that prevents leakage of a direct electromagnetic wave. 2. The ET according to claim 1, further comprising a radio wave shield installed before and after the antenna in a traveling direction of the vehicle to prevent leakage of an electromagnetic wave to a following vehicle.
C antenna. 3. The ETC antenna according to claim 1, wherein the radio wave shield is a plate-shaped body. 4. The ETC antenna according to claim 1, 2 or 3, wherein the antenna and the radio wave shield are installed below a roof of a tollgate. 5. The antenna is installed from below a roof of a toll gate via a supporter, and the radio wave shield is installed on a side surface of the supporter or the antenna. 2. The ETC antenna according to 2 or 3. 6. The ETC antenna according to claim 5, wherein the radio wave shield is installed via the supporter or the antenna via an elevating mechanism. 7. The ETC antenna according to claim 1, 2 or 3, wherein the radio wave shield is installed under a roof of a tollgate via a slide mechanism. 8. The ETC antenna according to claim 4, wherein the radio wave shield is installed under a roof of a tollgate via a hinge. 9. The ETC antenna according to claim 1, wherein the radio wave shield is made of a radio wave absorber or a metal shield plate.