JPH10256961A - Inductive radio antenna and inductive communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a break point at a transposition point of parallel two- wire inductive communication lines and to eliminate a need of a phase device for this elimination of the break point and to reduce the antenna space without isolation between air-core loops. SOLUTION: A line coupler, a ground equipment, etc., are connected to parallel two-wire induction lines 4 and 5, and an antenna 6 is connected to a receiver or a transmitter of a moving body moved on a track, and it is moved along induction lines 4 and 5. The antenna 6 consists of a loop antenna 61 wound in one direction like a loop and an antenna 62 formed to the shape of the figure 8 where the loop antenna is transposed in the center, and both antennas 61 and 62 are superposed one over the other in the state free from mutual induction, and they are synthesized by a synthesizer 10 and are connected to the receiver or the transmitter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inductive radio antenna, and more particularly, to an antenna connected to an inductive radio device mounted on a moving body moving along a parallel two-wire inductive communication line, and an inductive communication system. .

[0002]

2. Description of the Related Art Inductive radio antennas for mobile objects moving on fixed tracks such as new city traffic and cranes move along a parallel two-wire type guide communication line. FIG. 4 shows a conventional example.
Is a transmission / reception device of the terrestrial equipment (FIX), 2 is a line coupler (LC), and two guide lines (L1) 4, (L2) 5
It is a device for matching. The guide wires 4 and 5 extend in two parallel lines from the LC 2, and are connected to the terminating resistor (R) 3 via the intersecting point A which is twisted halfway. R3 is a device for matching the L1 and L2 lead wires.

An antenna (ANT) 71 moves along two parallel guide lines 4 and 5. As shown in FIG. 6, the details of the antenna 8 are an air-core loop antenna in which a conductor is wound several times.

The antenna 71 and the guide wires (L1) 4, (L
2) FIG. 5 shows a side view of the relative relationship of 5. Guidance lines 4, 5
A magnetic field Hi generated by a high-frequency current i flowing through the antenna 71 crosses the antenna 71. As a result, a reception level is obtained at the antenna 71, and guided wireless communication can be performed. The guide wires 4 and 5 are
It is necessary to twist a parallel two-wire induction wire to prevent induction trouble caused by other cables laid in the vicinity.
Is formed.

[0005]

Now, when the antenna 71 is used as a receiving antenna, when the antenna 71 moves and passes through the twist point A, the magnetic field Hi generated by the high-frequency current i and the number of magnetic flux crossings of the loop antenna 71 are changed. Becomes 0 and a break occurs in the reception level (FIG. 7).

As an improvement method, as shown in FIG.
An air-core loop antenna 81 and an antenna 8 whose phase is delayed (or advanced) by 90 ° with respect to the air-core loop antenna 81.
2 has been proposed by the combiner 10. In the figure, reference numeral 9 denotes a 90 ° phase shifter. The output of the combiner 10 is connected to a transmitter or a receiver of the mobile station. The reception level at this point has the characteristic shown in FIG.

However, in this case, since the loop portions of the antenna interfere with each other, it is necessary to keep a distance between the loops. As described above, since the two antenna loops are separated from each other and the phase shifter 9 is required, there is a disadvantage that an antenna mounted on a moving body has a large space.

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate a break at a twisted point of a parallel two-wire type inductive communication line, without using a phase shifter for eliminating the break, and at a distance between air core loops. In other words, the antenna space is reduced.

[0009]

SUMMARY OF THE INVENTION The object of the present invention is to provide a mutual induction between a loop antenna wound in one direction in a loop and an 8-shaped antenna in which a loop antenna wound in a loop is twisted at a center. Achieved by superimposing and synthesizing in the absence state.

[0010] According to the above means, the loop antenna comprises:
Coupled at a point other than the point where the parallel two-wire guide wire is twisted, the figure-eight antenna is coupled only at the point where the parallel two-wire guide wire is twisted, and the combination of both antennas does not cause a break in the reception or transmission level. Is obtained.

Further, the loop antenna and the figure-eight antenna are configured to be overlapped with each other without mutual guidance, so that the space of the antenna is reduced.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. Line couplers, ground facilities, terminating resistors, etc. to which parallel two-wire type induction wires (L1) 4, (L2) 5 are connected are the same as those of the conventional art. Not shown. The antenna 6 is connected to a receiver or a transmitter of a moving body moving on an orbit, and moves along the guide lines 4 and 5.

As shown in FIG. 2, the details of the antenna 6 include a loop antenna 61 wound in one direction in a loop and an 8-shaped antenna 62 in which the loop antenna wound in a loop is twisted at the center. And both antennas 61 and 6
2 are superimposed in a state where there is no mutual guidance, synthesized by the synthesizer 10, and connected to a receiver or a transmitter.

FIG. 3 shows the antennas 61 and 6 of FIG.
2 shows a state in which magnetic fluxes are disassembled. (A) is a loop antenna 61, (b) is an 8-shaped antenna 62, and the loop antenna 61 is coupled at a parallel portion of the guide wires 4 and 5, but is not coupled at a twisted portion A of the guide wire. The figure-eight antenna 62 is coupled at the stranded portion A of the guide wires 4 and 5, but is not coupled at the parallel portions of the guide wires. That is, the area of the portion B-1 divided into two by the twisted center of the antenna 62 and the portion B-2
And the magnetic flux Hi generated by the induction wires 4 and 5 and the magnetic flux generated by the loop antenna 61 are both 8
Because they are wound in a letter, they cancel each other and do not combine.
Further, the antennas 61 and 62 are fixed at positions where the number of magnetic flux crossings when a current flows mutually is zero.

As described above, the combined level of the antenna formed by superposing the antenna 61 and the antenna 62 can eliminate breakpoints in all areas including the points where the guide wires 4 and 6 are twisted. Further, since the two antennas 61 and 62 are not interfered with each other even when they are overlapped, they can be closely attached to each other, and the space for the antenna can be made sufficiently small.

When the antenna is used as a receiving antenna, the magnetic field H generated by the current i flowing through the induction wire
i and supplies the reception level to the mobile receiver,
When used as a transmission antenna, a transmission current is induced in an induction wire by a magnetic field generated by an antenna connected to the transmitter and transmitted to a ground station.

[0018]

As described above, according to the present invention, it is possible to obtain an antenna having no break in the same space as that of a conventional loop antenna which breaks at a point where a guide wire is twisted. Also,
Since it is not necessary to combine one of the two loop antennas using a 90 ° phase shifter as in the related art, the antenna space is reduced to less than half the size of the conventional one, and it is effective as an antenna for attachment to a moving body such as a vehicle. is there.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a coupling between an induction wire and an antenna according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of the antenna of FIG. 1;

FIG. 3 is an exploded view of the antenna of FIG. 2;

FIG. 4 is a configuration diagram of a conventional coupling between an induction wire and an antenna.

FIG. 5 is an explanatory view of coupling of the antenna of FIG. 4 with a guide wire.

FIG. 6 is a detailed view of a loop antenna.

FIG. 7 is an explanatory diagram of a reception level of a loop antenna.

FIG. 8 is another connection configuration diagram of a conventional induction wire and an antenna.

FIG. 9 is an explanatory diagram of the reception level of the antenna of FIG. 8;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Ground equipment (transmitter / receiver), 2 ... Line coupler, 3 ... Terminating resistor, 4 ... Lead wire (L1), 5 ... Lead wire (L2),
6 ... antenna, 61 ... loop antenna, 62 ... 8-shaped antenna.

Claims (2)

[Claims] 1. An induction radio antenna tightly coupled to a parallel two-wire induction wire, wherein a loop antenna wound in one direction in a loop and a loop antenna wound in a loop are twisted at a center. An induction radio antenna comprising: a U-shaped antenna, wherein the loop antenna and the 8-shaped antenna are superimposed and combined without mutual induction. 2. The induction wireless antenna according to claim 1,
An inductive communication system connected to a wireless device mounted on a mobile body moving along a parallel two-wire inductive communication line.