JPH08102222A - High frequency coaxial cable - Google Patents

Abstract

PURPOSE: To obtain a high frequency coaxial cable with its smaller outer diameter and with its higher electric characteristics without lowering productivity by providing a dielectric, a specific external conductor, and a protective covering layer on the outer circumference of an internal conductor. CONSTITUTION: A fluorescent resin is pushed out and molded on the outer circumference of an internal conductor 2, so as to obtain a dielectric 3. An external conductor 4 formed by a braided metal wire of a single paired tissue is formed on the outer circumference of this dielectric 3 on which a protective covering layer 5 is formed. Thereby, electric characteristics such as shield effect, attenuation quantity, etc., of a coaxial cable are good, which is effective when used for wiring in a small space or when complicated wiring is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency coaxial cable used in the field of communication equipment and the like, and more particularly to a high frequency coaxial cable having a small outer diameter.

[0002]

2. Description of the Related Art Conventionally, in the field of communication equipment and the like, an inner conductor, a dielectric provided on the outer periphery thereof, an outer conductor such as a metal wire braid provided on the outer periphery thereof, and a protective coating layer formed on the outer periphery thereof. Is used as a high-frequency transmission line.

In recent years, with the progress of communication equipment, it is often necessary to wire in a narrow space or to perform complicated wiring, and a demand for a high frequency coaxial cable having a small outer diameter is increasing.

In order to reduce the outer diameter of the high frequency coaxial cable, it is most effective to make the inner conductor thin and reduce the outer diameter of the dielectric. However, it is not easy to form an appropriate outer conductor on this small outer diameter dielectric, and the wire diameter of the metal wire braid can be made thin (for one carrier).
Although the number of strands is reduced to deal with it, the strands are cut off, which makes manufacturing difficult, lowers productivity, and raises costs. A structure in which a metal wire is wound horizontally is also often used as a means for forming an outer conductor, but the electrical characteristics are insufficient and it is not practical.

[0005]

SUMMARY OF THE INVENTION Therefore, the present invention solves the problems of the prior art, can be easily manufactured at low cost, and has a small outer diameter and excellent electrical characteristics. The challenge is to provide.

[0006]

In order to solve the above-mentioned problems, the inventors of the present invention replaced the conventionally used two-piece set organization with a one-piece set organization. However, the inventors have found that a good outer conductor can be formed on a dielectric having a small outer diameter, and that the electrical characteristics are rather improved, and the present invention has been completed.

That is, according to the present invention, the inner conductor, the dielectric provided on the outer periphery of the inner conductor, the outer conductor formed of the metal wire braid provided on the outer periphery of the dielectric, and the outer conductor formed on the outer periphery of the outer conductor. A high-frequency coaxial cable comprising a protective coating layer, wherein the metal wire braid has a single structure.

[0008]

[Function] By changing the structure of the metal wire braid from the two-braid structure to the one-braid structure, a metal braid suitable for a small dielectric can be formed without reducing the wire diameter and the number of wires per weight during braiding. Can be set.

Therefore, no breakage occurs during braiding, efficient production is possible, a metal wire braid can be formed at low cost, and a cable having a small outer diameter can be obtained.

Furthermore, even a single set of structures can be braided to the same density as the double set of structures, and the electrical characteristics are equal to or higher than those of the double set structure.

[0011]

1 is a perspective view showing an example of a high-frequency coaxial cable according to the present invention, in which a dielectric material 3 extruded from a tetrafluoroethylene-hexafluoropropylene copolymer resin is provided on the outer periphery of an inner conductor 2, The metal wire braid 4 provided on the outer periphery of this dielectric and the outer periphery thereof are covered with the protective coating layer 5 to form the high-frequency coaxial cable 1.

For example, in the high-frequency coaxial cable shown in FIG. 1, a silver-plated copper covered steel wire having an outer diameter of 0.29 mm is used as the inner conductor 2, and a tetrafluoroethylene-hexafluoropropylene copolymer resin is provided on the outer periphery thereof. About 0.2
It was extruded to a thickness of 65 mm to obtain a dielectric 3. Then, using an annealed copper wire (diameter 0.08 mm) plated with silver on the outer periphery of the dielectric 3, one set is formed with an 8/6 braided structure (6 strands per spindle, 8 strands driven). A metal wire braid 4 having a structure was braided, and a protective coating 5 made of tetrafluoroethylene-hexafluoropropylene copolymer resin (FEP) having a thickness of 0.3 mm was formed on the outer periphery thereof to obtain a high frequency coaxial cable 1. The outer diameter of the obtained high frequency coaxial cable was about 1.82 mm.

FIG. 2 is an enlarged plan view of the metal wire braid 4 having the one-piece set structure.

On the other hand, for comparison, in place of the metal wire braid 4, a 16/3 braid structure (3 strands per spindle,
When a high frequency coaxial cable was produced in the same manner as in the above-mentioned example except that a metal wire braid having a two-piece structure was braided with 16 pieces of the number of implants), the outer diameter was about 1.82 mm.

FIG. 3 is an enlarged plan view of the metal wire braid having the two-piece structure.

The high-frequency coaxial cable (Example) having the metal wire braid having the one-piece structure and the high-frequency coaxial cable having the metal wire braid having the two-piece structure (comparative example) thus obtained were described in E. M. I. One of the measuring methods, C.I.
I. S. P. R. Pub. The shielding effect was evaluated by the absorbing clamp absorption method in Chapter 16 and Chapter 8, and the attenuation was measured by the network analyzer method.

The results are shown in Tables 1 and 2, and the examples showed superior electrical characteristics to the comparative examples.

[0018]

[Table 1]

[0019]

[Table 2]

In the above embodiment, the inner conductor has 0.29 mm.
Although an example using a single wire of the silver-plated copper-covered steel wire is shown, the material of the inner conductor is not limited to this, and any conventionally used inner conductor can be used, Furthermore, not limited to a single wire, a twisted wire may be used.

As the dielectric, a tetrafluoroethylene-tetrafluoropropylene copolymer was used in the examples, but any resin can be used as long as it is a resin that can be used as the dielectric of a coaxial cable. be able to. For example, fluororesins such as tetrafluoroethylene resin and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin, foams of these,
Furthermore, polyethylene, polyvinyl chloride, etc. can be illustrated. Further, as the metal wire used for the metal wire braid as the outer conductor, any commonly used metal conductor can be used, and if the protective coating layer is also made of an insulating material, its material and thickness are It doesn't matter.

[0022]

According to the present invention, a high-frequency coaxial cable having a small outer diameter can be easily manufactured at low cost, and the electrical characteristics such as the shielding effect and the attenuation amount are excellent, and the wiring can be performed in a narrow space. It is extremely effective when performing wiring or performing complicated wiring.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a high frequency coaxial cable of the present invention.

FIG. 2 is an enlarged plan view of a single braided metal braid used in the present invention.

FIG. 3 is an enlarged plan view of a conventional metal braid having a two-piece structure.

[Explanation of symbols]

 1 high frequency coaxial cable 2 inner conductor 3 dielectric 4 metal wire braid 5 protective coating layer

Claims (1)

[Claims] 1. A high frequency wave comprising an inner conductor, a dielectric provided on the outer periphery of the inner conductor, an outer conductor formed of a metal wire braid provided on the outer periphery of the dielectric, and a protective coating layer formed on the outer periphery of the outer conductor. A high-frequency coaxial cable, wherein the structure of the metal wire braid is one set in the coaxial cable.