JPS6038902A - Spiral conductor type leakage cable - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to the structure of a helical conductor type leaky cable.

Prior Art and Problems A conventional leaky spiral conductor cable is made by twisting a pair of conductors 1 and 2 in a spiral shape at a constant pitch P, as shown in Figure 1. As shown in the figure, a core type in which the conductors 1 and 2 are embedded in the center of the insulator 3, and a so-called spacer type in which the conductors 1 and 2 are inserted into grooves formed in the insulator 3 as shown in Fig. 3 are adopted. has been done.

By the way, the following relationship holds true between the radiation frequency f and the pitch P of such a spiral conductor type leaky cable.

(c/p)−(Kλ/(λ to 1+))<f/n<(c
/p)·(Kλ/(1−λ))−(1) where C is the speed of light, λ is the wavelength shortening rate, and n is a natural number.

In equation (1), Kλ is determined by the insulator and is usually 0.5
It is about 0.95. Therefore, if it is designed to be used at 150 Mtlz or less, the pitch P must be 1 to 2 m or more. For this reason, the helical angle becomes extremely small, making it extremely difficult to manufacture with a uniform pinch.

Purpose of the Invention The present invention improves these conventional drawbacks, and
The object of the present invention is to provide a leaky spiral conductor cable that can obtain a sufficiently low radiation frequency without requiring a long pinch.

Structure of the Invention In the spiral conductor type leaky cable of the present invention, the cable has P
, , P2 have different periods (double period).

If the two pairs have different helical pinches p, , p2, then
If the directions of the spirals are the same, the relative pitch P between the pairs is P = P + P 2/ (P + P 2) - 12). Therefore, by changing P2 (or P+), it is possible to realize an arbitrary pitch P in the range of 0<P<(value).

Since the strength of the electric field and/or magnetic field propagating through the cable, that is, the intensity distribution of the wave source, can be changed by other factors than the helical pinch, the period P l + P 2 depends on factors such as the conductor diameter and conductor spacing in addition to the helical pitch of the conductor. Any parameters related to the structure of the cable, such as dimensions, thickness of insulator, degree of foaming, etc., can be set.

At this time, it is preferable that the changes in each parameter be sinusoidal in order to widen the effective radiation bandwidth of the cable. Embodiments of the invention FIGS. 4 to 6 are structural explanatory diagrams of different embodiments of the invention. This is a cross-section of a helical conductor type leaky cable viewed from an angle.

The embodiment shown in FIG. 4 has a conductor 12 constituting one core wire.
．． 13 are embedded approximately in the center of the insulators 16 and 17, and are twisted together at a helical pitch P2 and housed in a tube 18 made of tape or thread of a low-loss insulating material. Conductors 10.11 constituting the other core wire embedded approximately in the center of the body 14.15 are twisted together at a helical pitch P1 and housed in a tube 19.

Further, in the embodiment shown in FIG. 5, a conductor 10 covered with an insulator 14 and a conductor 11 covered with an insulator 15 are twisted together in a spiral pinch section P and housed in a tube 21.
2 and a conductor 13 coated with an insulator 17 are twisted together at a helical pitch P2 and housed in a tube 20, and tubes 20 and 21 are housed in a tube 22. Conductor 1
0.11 constitutes one conductor, and conductor 12.13 constitutes the other conductor.

The embodiment of FIG. 6 shows a twisted helical pinch of a conductor 10.11 which constitutes one conductor covered with an insulator 14.15 and a conductor 12 which constitutes the other conductor covered with an insulator 16.17. The twisted helical pinch of .13 is housed in the tube 20.21 with the same Pl, and this tube 20.21 is connected to the conductor 10.
．． The two pairs of twisted pinches of conductor 11 and conductor 12 and 13 are P2
The fibers are twisted together and stored in the tube 22 so that

When using the cables shown in FIGS. 4 to 6, for example, as shown in FIG.
The output of the oscillator P is connected between the two pairs of conductors.

FIG. 8 is an external view of another embodiment of the present invention, in which a conductor 3o constituting one core wire and a conductor 31 constituting the other core wire.
The outer diameter of the insulators 32, 33 covering the conductors 32, 33 is changed at a pitch P2, and the conductors 30, 31 covered with such insulators 32, 33 are twisted together at PI.

FIG. 9 is an external view of still another embodiment of the present invention, in which grooves with pitch PI are formed in insulators 40 and 41, and conductors 42 constituting one core wire and the other core wire are inserted therein. The constituent conductor 43 is housed therein, and the insulators 40 and 41 are twisted together with a P2 pinch.

As described in detail, according to the present invention, the cable includes a PI,
Since the cable is configured to have different periods of P2, even if there is an upper limit to the helical pinch of the conductor due to manufacturing reasons, the cable can have any period by using two different pitches P, P2 that are below the upper limit. becomes possible. Therefore, manufacturing becomes extremely easy. In addition, by setting two different pinches independently to match the desired radiation frequency band, it is possible to obtain any two different radiation frequency bands, which also has the effect of allowing different users to share one cable. .

[Brief explanation of drawings]

FIGS. 1 to 3 are explanatory diagrams of conventional spiral conductor type leaky cables, FIGS. 4 to 6, FIGS. 8 and 9 are explanatory diagrams of different embodiments of the present invention, and FIG. It is a figure which shows the usage method of the spiral conductor type leaky cable of this invention. lO~13.30.31.42.43 is a conductor, 14~1
7.32°33 and 40.41 are insulating bands. Patent applicant Sumitomo Electric Industries Co., Ltd. Patent attorney Patent attorney Tamamushi Gobu Department Figure 1 Figure 4 Figure 5 Figure 6 Figure 1 Figure 7 Figure 8 Figure 9

Claims (1)

[Claims] In a helical conductor type leaky cable, it consists of two sets of core wires used in pairs, each core having one or two cores.
A spiral conductor type leaky cable consisting of a single conductor and characterized by having two different periods throughout the cable.