JPH0775286B2 - Electromagnetic radiation cable - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cable for radiating electromagnetic fields, which is installed along a railroad track and is used as a train radio with a train, installed on a tunnel side wall, as a radio in a tunnel with a mobile vehicle, and as an underground mall The present invention relates to an electromagnetic field radiation cable used as an antenna that is installed and constitutes a wireless communication transmission system such as an underground disaster prevention radio.

[0002]

2. Description of the Related Art Conventionally, a radio communication transmission system such as a train radio with a train installed along a railroad track, a radio in a tunnel installed on a side wall of a tunnel, a radio in a tunnel with a mobile vehicle, and an underground disaster prevention radio installed in an underground mall As the antenna, there is a leaky coaxial cable (LCX) in the VHF and UHF bands.

This leaky coaxial cable utilizes a leak of an electromagnetic field from a slot by providing a slot formed at an angle with the axis of the cable on an outer shell of an aluminum conductor based on a polyethylene pipe.

[0004]

A leaky coaxial cable in the VHF and UHF bands has an outer diameter of 5 to provide a slot.
The thickness is as thick as 0 mm, and it is necessary to remove the slot from the aluminum, which is the outer conductor, at a required angle during the manufacturing process. Further, the leaking direction of the electromagnetic field of the leaky coaxial cable is strong in the direction facing the slot, and the leaking electromagnetic field in the direction perpendicular to the axis of the cable is not uniform. Further, since the leaky coaxial cable is based on a polyethylene pipe having a diameter of 40 mm, it cannot be bent easily and the installation is restricted.

The present invention has been made in view of the above circumstances, and the amount of electromagnetic field radiation in the direction perpendicular to the axis of the cable can be made uniform without increasing the outer diameter of the cable, and the electromagnetic field radiation can be easily performed. It is an object of the present invention to provide an electromagnetic field radiation cable whose amount can be controlled to a required value and whose productivity can be improved.

[0006]

In order to solve the above problems, the present invention provides an electromagnetic field radiation element of 1/2 wavelength as an additional outer conductor on the outer circumference of an outer conductor of a cable composed of an inner conductor and an outer conductor. , The midpoint in the axial direction of the ½ wavelength electromagnetic field radiating element, that is, the ¼ wavelength point is electrically connected to the outer conductor of the cable, and the ½ wavelength electromagnetic field radiating element emits electromagnetic field. Done.

Further, one or a plurality of ½ wavelength electromagnetic field radiating elements are arranged, a ¼ wavelength sleeve is provided at both ends thereof, and a ½ wavelength electromagnetic field between the ¼ wavelength sleeves is provided. The amount of electromagnetic field radiation is controlled to the required value by the number of radiating elements installed.

[0008]

With the above-mentioned means, the electromagnetic wave radiating element of 1/2 wavelength provided on the outer circumference of the outer conductor of the cable controls the electromagnetic field radiation, and the electromagnetic field radiation amount is controlled to a required value by the number of the electromagnetic field radiation elements.

Therefore, according to the present invention, since there is no slot for the aluminum outer conductor on the basis of a polyethylene pipe such as a leaky coaxial cable, it is not necessary to increase the outer diameter of the cable, and it is possible to form a cable perpendicular to the axis of the cable. The amount of electromagnetic field radiation in each direction is also uniform.

Further, in the manufacturing process as well, since the outer conductor of the cable can be constructed by simply covering the outer conductor of the electromagnetic wave with a half-wavelength radiating element and joining it, continuous production is possible by adding an additional outer conductor process to the manufacturing process of the cable. You can

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIGS. 1, 2, 3 and 4 show a first embodiment of the present invention, FIG. 1 is a perspective view, FIG. 2 is a sectional view, and FIG.
Is a cross-sectional view taken along the line AA ′ of FIG. 2 and FIGS.
(C) has shown the conceptual diagram of radiation electromagnetic field control. Figure 4
4B shows the relative signal level and the electromagnetic field radiation amount with respect to the cable length, and FIG. 4C shows 1/2 of the cable length.
The electric field level at the same distance from the electromagnetic field radiating element 2 of the wavelength is shown.

That is, the electromagnetic field radiation cable of the first embodiment is
On the basis of a normal coaxial cable such as 5D2V, 5D2W, an electromagnetic field radiating element 2 of 1/2 wavelength concentric with the outer conductor 1 of the coaxial cable is provided on the outer circumference of the outer conductor 1 of the coaxial cable as an additional outer conductor. The midpoint in the axial direction of the electromagnetic wave radiating element 2 of 1/2 wavelength, that is, the point 3 of 1/4 wavelength is electrically connected to the outer conductor 1 of the coaxial cable.

Further, one or a plurality of the half-wavelength electromagnetic field radiating elements 2 are arranged, and one end of the sleeve is electrically connected to the outer conductor 1 at both ends thereof. 7 is provided.

1/2 between the 1/4 wavelength sleeves 6 and 7
The electromagnetic field radiation element 2 having a wavelength controls electromagnetic field radiation, and the amount of electromagnetic field radiation can be controlled by the number of the electromagnetic field radiation elements 2 installed. 5, 6 and 4 (a),
(B), (c) has shown Example 2 of this invention.
5 is a perspective view and FIG. 6 is a sectional view.

That is, the electromagnetic field radiation cable of the second embodiment is
In a two-conductor structure having an inner conductor 4 and an outer conductor 5 made of a quadrangular tubular waveguide, the outer conductor 5 has a 1/2 outer circumference.
The electromagnetic field radiation element 2 having a wavelength is provided as an additional outer conductor. A midpoint in the axial direction of the half-wavelength electromagnetic field radiating element 2, that is, a quarter-wavelength point 3 is electrically connected to the outer conductor 5.

Further, one or a plurality of the half-wavelength electromagnetic field radiation elements 2 are arranged, and one end of the sleeve is electrically connected to the outer conductor 5 at both ends of the quarter-wave sleeve 6, 7 is provided.

1/2 between the 1/4 wavelength sleeves 6 and 7
The electromagnetic field radiation element 2 having a wavelength controls electromagnetic field radiation, and the amount of electromagnetic field radiation can be controlled by the number of the electromagnetic field radiation elements 2 installed.

[0019]

As described above, according to the present invention, 1 /
The two-wavelength electromagnetic field radiation element controls the electromagnetic field radiation, and the number of electromagnetic field radiation elements can control the electromagnetic field radiation amount to a required value.

Further, according to the present invention, since there is no slot for the aluminum outer conductor on the basis of a polyethylene pipe such as a leaky coaxial cable, there is no need to increase the outer diameter of the cable, and it is possible to form a cable perpendicular to the axis of the cable. The radiation amount of the electromagnetic field in the direction is also uniform, the bending is easy, and the restriction of the laying place can be relaxed.

Further, in the manufacturing process as well, since it can be constructed by only covering the outer conductor of the cable with the electromagnetic field radiating element of 1/2 wavelength and joining it, there is no need to remove the slot like a leaky coaxial cable, Addition to the manufacturing process of the cable, continuous production is possible by adding the process of the outer conductor.

[Brief description of drawings]

FIG. 1 shows a perspective view of a first embodiment of the present invention.

FIG. 2 shows a sectional view of the first embodiment of the present invention.

FIG. 3 is a sectional view taken along the line AA ′ of FIG.

FIG. 4 is a conceptual diagram of radiated electromagnetic field control according to the first and second embodiments of the present invention.

FIG. 5 shows a perspective view of a second embodiment of the present invention.

FIG. 6 shows a sectional view of a second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Outer conductor of a coaxial cable, 2 ... 1/2 wavelength electromagnetic field radiating element, 3 ... 1/2 wavelength axial midpoint (1/4 wavelength point), 4 ... Inner conductor 5 ... Outer conductor, 6 ... 1/4 wavelength sleeve, 7 ... 1/4 wavelength sleeve.

Claims (4)

[Claims] 1. A half wavelength electromagnetic field radiating element concentric with the outer conductor of the coaxial cable is provided on the outer circumference of the outer conductor of the coaxial cable, and the midpoint in the axial direction of the half wavelength electromagnetic field radiating element. The electromagnetic field radiation cable is characterized in that the point of 1/4 wavelength is electrically connected to the outer conductor of the coaxial cable. 2. An electromagnetic field radiation cable comprising two conductors having a structure having an inner conductor and an outer conductor, wherein a half wavelength electromagnetic field radiation element is provided on the outer periphery of the outer conductor, and the half wavelength electromagnetic field radiation is provided. An electromagnetic field radiation cable, characterized in that a 1/4 wavelength point, which is the midpoint in the axial direction of the element, is electrically connected to an external conductor. 3. One or a plurality of half-wavelength electromagnetic field radiating elements concentric with the outer conductor of the coaxial cable are arranged around the outer conductor of the coaxial cable, and each half-wavelength electromagnetic field is arranged. The 1/4 wavelength point, which is the midpoint in the axial direction of the radiating element, is electrically connected to the outer conductor of the coaxial cable.
A quarter-wave sleeve in which one end of the sleeve is electrically connected to an external conductor is provided at each end of each half-wave electromagnetic field radiating element in which one or a plurality of elements are arranged.
An electromagnetic field radiation cable, wherein the electromagnetic field radiation amount is controlled by the number of half-wavelength electromagnetic field radiation elements installed between wavelength sleeves. 4. An electromagnetic field radiation cable composed of two conductors having a structure having an inner conductor and an outer conductor, wherein one or a plurality of half-wavelength electromagnetic field radiation elements are arranged on the outer circumference of the outer conductor. A ½ wavelength electromagnetic field emission, in which one or a plurality of ½ wavelength electromagnetic fields are electrically connected to an outer conductor at a midpoint in the axial direction of the ½ wavelength electromagnetic field emission element. A quarter wavelength sleeve in which one end of the sleeve is electrically connected to an external conductor is provided at each end of the element, and electromagnetic field emission is performed by the number of half wavelength electromagnetic field emission elements between the quarter wavelength sleeves. An electromagnetic field radiation cable characterized by controlling the quantity.