JPH0198980A - Antenna for leakage coaxial cable - Google Patents

Abstract

PURPOSE:To miniaturize the title antenna, to suppress the influence by standing, and also, to improve the detection accuracy of a leakage coaxial cable (LCX) boundary point by constituting said antenna so that an interval, etc. of two sets of antennas which are connected to a radio equipment for moving on the LCX are made variable. CONSTITUTION:Antennas 10, 11 are constituted so that an interval thereof is variable in parallel. In the antennas which are constituted in such a way, an interval 19 is adjusted so that the electric field strength radiated to an LCX from the antenna 10 is weak, that is, at the time of forming a trough, the electric field strength by the antenna 11 is strong, namely, goes to a crest. In such a way, for instance, as for the electric field strength 17 inputted to a receiver 1, the crest and the trough of the electric field strength 8 and 15 negate each other, and said strength goes to an electric field which is averaged and whose fluctuation is small, therefore, even when a transmitter 5 moves in the moving direction 13, the attenuation goes to smooth. In such a case, the electric field strength inputted to a receiver 2 also rises smoothly in the same way, and by adjusting the receiving sensitivity of both the receivers, a boundary passing point of a moving body can be detected easily. In such a way, the antenna is miniaturized, the influence by standing is suppressed, and also, the detection accuracy of an LCX boundary point can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an antenna used for mobile radio communication using a leaky coaxial cable, for example, and particularly to an antenna for a leaky coaxial cable for detecting the position of a moving object.

[Conventional technology]

Figure 3 shows the system of conventional wireless equipment. In the figure, (1) and (2) are wireless receivers, and (3) and (4) are wireless receivers.
is a leaky coaxial cable (hereinafter referred to as LCX), (5
) is the radio transmitter, (6J, (7) is the receiver (1),
Coaxial cable connecting (2) and LCX cable (3), (4), αQ is the antenna, 4 is the coaxial cable connecting the transmitter (5) and antenna Q0, (to) is the transmitter (5)
) and the direction in which the antenna αQ moves, (8) is the antenna α
It shows the fluctuation in the electric field strength of the radio waves emitted from Q and received by LCX (3). Similarly, (9) represents the variation in the electric field strength received at LCX (4).

Next, the operation will be explained. When the radio transmitter (5) and antenna 00 move while emitting radio waves from LCX (3) to LCX (4), base station radio reception i (1)
and (2), electric field strength fluctuation (8) and (
9) is obtained and the received electric field strength decreases, the LCX
Escape from the section (3) is detected, and entry into the LCX section (4) is detected by the rise in the received electric field.

[Problem that the invention seeks to solve]

Conventional antennas are composed of a single unit, so they are susceptible to the effects of standing and LCX slots, and near the LCX boundary, the electric field received by both LCXs fluctuates greatly, so the LCX boundary is clearly defined due to the difference in electric field strength. In addition, in order to suppress the influence of standing, it is necessary to line up many antennas, but there is a problem that the size becomes large.

This invention was made to solve the above-mentioned problems, and aims to provide an LCX antenna that is small and can suppress the effects of standing, and that improves the detection accuracy of LCX boundary points. .

[Means for solving problems]

The antenna for LCX according to the present invention is capable of varying the interval between two antennas and uses a directional antenna.

[Effect]

In this invention, by adjusting the interval between two antennas, the LCX received electric field strength by each antenna is input to the radio receiver at the same time at the peak and valley, and the receiver input electric field strength is determined by combining the respective electric fields. fluctuation becomes smaller.

[Embodiments of the invention]

This embodiment will be explained below with reference to the figures. In FIG. 1, (1) to (7) are exactly the same as above.

00.0υ is the antenna, ← the needle distributor, (8) is the antenna α
Received electric field at LCX (3) due to antenna 0, (9) is received electric field strength at LCX (4) due to antenna (10), aQ is received electric field strength at LCX (3) due to antenna aη, σQ is LCX due to antenna 01 (4) The received electric field strength at , ση is the received electric field strength (8) and Q
119 is combined and input to the receiver (1), (to) is the input electric field strength to which the received electric field strength (9) and α distortion are combined and input to the receiver (2), (to) is The moving direction of the transmitter (5) and the antenna Q□, C11), (1
91 is the distance between the antenna αO and συ.

In the antenna configured as described above, the interval α is adjusted so that when the electric field intensity radiated to the antenna 00 to LCX is weak, that is, a valley, the electric field intensity due to the antenna CIυ is strong, that is, a peak. As a result, for example, the electric field strength ση input to the receiver (1) is equal to the electric field strength (8) and a
The peaks and valleys of 5 cancel each other out, creating an averaged electric field with small fluctuations, resulting in smooth attenuation even when the transmitter (5) moves in the moving direction (c). In this case, the receiver (2
) also rises smoothly, and by adjusting the reception sensitivities of both receivers, it becomes possible to easily detect the boundary crossing point of a moving object.

In the above embodiment, the distance between the antennas αO9αη can be varied in parallel, but the same effect can be expected even if the angle of the center of directivity of the two antennas can be varied.

Figure 2 shows the angle (A) between the antenna α0 and the time a.
It's pointing in the X direction.

According to this figure 2, by changing the angle -,
By making the peaks and valleys of the electric field strength of the LCX caused by each antenna coincide with each other, it is possible to suppress fluctuations in the electric field strength.

Incidentally, in the above description, the antenna is used as the transmitting side and the LCX is used as the receiving side, but it goes without saying that the LCX can be used as the transmitting side and the antenna as the receiving side.

〔Effect of the invention〕

As described above, according to the present invention, fluctuations in the electric field intensity can be stabilized only by the positional relationship between the antennas, so that the apparatus can be manufactured at low cost and has the advantage of being highly accurate.

[Brief explanation of the drawing]

FIG. 1 (→(b) is a system diagram and electric field strength diagram showing one embodiment of this invention, FIGS. 2(a) and (b) are a system diagram and electric field strength diagram showing another embodiment of this invention, Figure 3(a)
(b) is a diagram of a conventional LCX antenna and electric field strength. (1), (2) are wireless receivers, (3), (4)
, (5) is the LCX cable, (5) is the wireless transmitter,
(6) and (7) are coaxial cables, α0゜Qη is an antenna,
@ is a coaxial cable, and α is a distributor.

Claims (1)

[Claims] (1) An LCX cable connected to a base station radio, and two antennas with a synthesizer/distributor connected to a radio moving on the LCX cable, with variable spacing or directivity direction. Aerial line for leaky coaxial cable.