JP3712846B2 - communication cable - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a communication cable, and more particularly, to a communication cable having at least one cable core wire and a jacket containing an insulating material covering the cable core wire.
[0002]
[Prior art]
As is well known, a communication cable is composed of at least one cable core and an outer jacket that includes an insulating material that covers the cable core. As an insulating material constituting the outer cover, a plastic such as polyethylene (PE) or polyvinyl chloride (PVC) or PEF obtained by firing PE is used.
[0003]
Here, in recent electronic devices in which communication cables are used, the development of high-frequency information processing technology in digital circuits and the spread of devices using high frequencies have progressed, and in particular, electronic devices using quasi-microwave bands or microwave bands. The spread of equipment is remarkable. Such electronic devices are remarkably demanded for miniaturization and weight reduction, and high density mounting of electronic components is the biggest technical issue.
[0004]
Accordingly, electronic components mounted overly densely, printed wiring, wiring between modules, and the like are extremely close to each other, and further, the signal processing speed is increased, so electrostatic coupling and / or In addition, there are many cases in which the normal operation of an electronic apparatus is hindered due to an increase in line-to-line coupling due to electromagnetic coupling or interference due to radiation noise.
[0005]
Conventionally, countermeasures such as filtering, shielding, and strengthening of the ground system have been taken inside the electronic device against such so-called high-frequency electromagnetic interference, and the cable has been provided with a conductive sheet or knitted wire. A countermeasure is taken by attaching a magnetic material in the form of a sleeve to the so-called shielded cable or cable.
[0006]
[Problems to be solved by the invention]
However, external measures are limited by space, weight, etc. Further, in the countermeasure parts currently on the market, a large suppression effect cannot be expected in the microwave band region.
[0007]
Further, since the shielded cable is a conductor, there is a drawback that electromagnetic coupling by reflection from an unnecessary radiation source is promoted even if a shielding effect (attenuation effect through which radio waves are transmitted) is obtained. In order to eliminate the disadvantage, it is considered effective to suppress unnecessary radiation using the high-frequency permeability characteristics of the magnetic material as a secondary countermeasure against electromagnetic interference.
[0008]
Therefore, the subject of this invention is providing the communication cable which can suppress an unnecessary radiation noise effectively.
[0009]
[Means for Solving the Problems]
According to the present invention, in a communication cable having at least one cable core and an outer jacket including an insulating material covering the cable core, the outer insulating material is a flat or needle-shaped soft magnetic powder. A communication cable is obtained, which is composed of a composite magnetic body made of an organic binder, and the soft magnetic powder is a metal or alloy whose surface is oxidized .
[0010]
Further, according to the present invention, in a communication cable having at least one cable core wire and a jacket including an insulating material that covers the cable core wire , the cable core wire is disposed between the cable core wire and the jacket . A composite magnetic layer composed of a flat or needle-like soft magnetic powder and an organic binder is formed so as to cover the surface, and the soft magnetic powder is a metal or alloy having an oxidized surface portion. A cable is obtained.
[0011]
Further, according to the present invention, in a communication cable having at least one cable core wire, a jacket including an insulating material covering the cable core wire, and a conductive sheet or knitted wire on the surface of the cable core wire, Between the cable core wire and the conductive sheet or the braided wire, a composite magnetic material layer composed of a flat or needle-like soft magnetic powder and an organic binder is formed so as to cover the surface of the cable core wire, A communication cable is obtained in which the soft magnetic powder is a metal or alloy having an oxidized surface portion .
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a communication cable according to a first embodiment of the present invention. The cable 10 includes a plurality of cable core wires 11 and a jacket 12 that covers the cable core wires 11. The jacket 12 is formed as a composite magnetic body formed by kneading a flat soft magnetic powder 13 with an organic binder 14 and oriented and arranged in the surface of the cable.
[0014]
FIG. 2 is a diagram showing a communication cable according to the second embodiment of the present invention. The cable 10 is configured in such a manner that a cable is covered with a composite magnetic material in which a flat soft magnetic powder 13 is oriented and arranged in an organic binder 14 on the surface of a plurality of cable core wires 11, and further a composite magnetic material layer Is covered with a jacket 12 made of the same resin material as that of the organic binder 14.
[0015]
FIG. 3 is a diagram showing a communication cable according to the third embodiment of the present invention. The cable 10 includes a composite magnetic body in which a flat soft magnetic powder 13 is oriented and arranged in an organic binder 14 so as to cover the surface of a plurality of cable core wires 11. A conductive braided wire 15 is provided on the surface, and a jacket 12 made of an insulating material is provided on the outer surface.
[0016]
Here, as the soft magnetic powder,. Typical examples of such materials include iron-aluminum-silicon alloys (Sendust (registered trader 8)) and iron-nickel alloys (permalloy), which have a high high-frequency magnetic permeability. In addition, the soft magnetic powder according to the embodiment of the present invention is finely powdered and used by oxidizing the surface portion.
[0017]
The aspect ratio of the soft magnetic powder is preferably sufficiently large, for example, 5: 1 or more. The organic binder used in the present invention is a thermoplastic resin such as polyester resin, polyvinyl chloride resin, polyvinyl butyral resin, polyurethane resin, cellulose resin, nitrile-butadiene rubber, styrene-butadiene rubber, or the like. And a thermosetting resin such as an epoxy resin, a phenol resin, a phenol resin, an amide resin, and an imide resin.
[0018]
In this embodiment, a cylindrical multi-core cable has been described as an example. However, a flat cable may be used and the shape of the cable is not limited. FIG. 4 shows a form applied to a flat cable. In the composition of the soft magnetic powder and organic binder used in the embodiment of the present invention, 80 parts by weight of a soft magnetic powder composed of Fe-Al-Si having an average particle size of 30 μm and an aspect ratio of 5 or more, It consists of 20 parts by weight of chlorinated polyethylene as an organic binder.
[0019]
Sendust alloy powder is oxidized in a nitrogen-oxygen mixed gas atmosphere with an oxygen partial pressure of 20%, and it has been confirmed that an oxide film is formed on the surface. These are heat kneaded and injection molded to obtain a molded body. The volume resistivity plane of the composite magnetic material was measured and found to be 1 × 10 ⁷ Ω · cm.
[0020]
A sheet having a thickness of 0.5 mm made of the composite magnetic material having the above composition was produced by roll rolling to obtain Sample 1. Furthermore, the specimen 1 was lined with 200 mesh copper braided wire to obtain a trial 2. As a comparative example, a copper knitted wire 200 mesh was prepared. The noise suppression effect was evaluated by measuring the transmission level and the coupling level in the vicinity of the sheet of the sample 1, the sample 2, and the sample of the comparative example with the measuring apparatus shown in FIGS. 5 (a) and 5 (b). did. The measuring apparatus includes an electromagnetic wave source oscillator 21, an electromagnetic field intensity measuring device 22, an electromagnetic field transmitting micro loop antenna 23 having a loop diameter of 2 mm or less connected to the electromagnetic wave source oscillator 21, and an electromagnetic field intensity measuring device. And an electromagnetic field receiving micro-loop antenna 24 having a loop diameter of 2 mm or less connected to 22. As the electromagnetic field strength measuring device 22, for example, a spectrum analyzer can be used, and the measurement was performed based on the electromagnetic field strength in a state where the evaluation sample 100 (not shown) does not exist.
[0021]
FIG. 5A shows an evaluation system for measuring the transmission level (dB) with a measuring device, and an evaluation sample 100 is positioned between the electromagnetic field transmitting microloop antenna 23 and the electromagnetic field receiving microloop antenna 24. . FIG. 5B shows an evaluation system for measuring the coupling level (dB) with a measuring device, and an electromagnetic field transmitting microloop antenna 23 and an electromagnetic field receiving microloop antenna 24 are arranged opposite to each other on one side of the evaluation sample 100. I let you.
[0022]
FIG. 6A and FIG. 6B show the transmission levels measured by the evaluation system shown in FIG. 5A and FIG. 5B for the sample 1, the sample 2, and the comparative example, respectively. (DB) and binding level (dB) are shown. In FIG. 6A, the horizontal axis represents frequency (GHz), and the vertical axis represents transmission level (dB). In FIG. 6B, the horizontal axis represents frequency (GHz), and the vertical axis represents the coupling level (dB). In FIGS. 6A and 6B, the sample 1 is indicated by (1), the sample 2 is indicated by (2), and the comparative sample is indicated by (3).
[0023]
6A and 6B show the following within the measurement frequency range. Sample 1 had a transmission level of −4 (dB) and a binding level of −4 (dB). Sample 2 had a transmission level of −45 (dB) and a binding level of +2 (dB), and the comparative sample had a transmission level of −45 (dB) and a binding level of +6 (dB). Comparing the above results as the suppression effect, the larger the numerical value in the transmission level, the greater the suppression effect, and the greater the negative value, the greater the suppression effect. That is, it can be seen that only the composite magnetic material as the sample 1 has a suppressing effect on both transmission and coupling. Furthermore, when the copper braided wire of the sample 2 is lined, it can be seen that although the bonding level is somewhat deteriorated, the suppression of the transmission level is further increased. In contrast, the copper braided wire, which is a comparative sample, has a high coupling level of +6 dB, although the transmission level is suppressed.
[0024]
Therefore, in the case of a comparative trial using only a conductor, only a shielding effect with reflection can be obtained. That is, although the shielding effect from the cable to the outside can be expected, there is a possibility that secondary radiation occurs between the cables in the same plane, and a secondary failure such as an increase in crosstalk or malfunction occurs.
[0025]
【The invention's effect】
According to the present invention, there is no reflection as seen in a conductor, and electromagnetic waves can be suppressed by dispersing and absorbing unnecessary radio wave energy.
[0026]
Further, according to the present invention, the transmission level and the coupling level can be controlled by combining conductors such as copper braided wires.
[Brief description of the drawings]
FIG. 1 is a diagram showing a communication cable according to a first embodiment of the present invention.
FIG. 2 is a diagram showing a communication cable according to a second embodiment of the present invention.
FIG. 3 is a diagram showing a communication cable according to a third embodiment of the present invention.
FIG. 4 is a diagram showing a form in which the present invention is applied to a flat cable.
FIG. 5A shows an evaluation system for measuring a transmission level (dB) with a measuring device, and FIG. 5B shows an evaluation system for measuring a binding level (dB) with a measuring device.
6 (a) and (b) show the transmission level (dB) and the binding level (dB) measured by the evaluation system shown in FIG. 5 (a) for Sample 1, Sample 2, and Comparative Sample, respectively. ).
[Explanation of symbols]
11 Cable core wire 12 Jacket 13 Soft magnetic powder 14 Organic binder 15 Braided wire

Claims (3)

A communication cable having at least one cable core wire and a jacket containing an insulating material covering the cable core wire, wherein the jacket insulating material is a composite comprising a flat or needle-like soft magnetic powder and an organic binder. A communication cable made of a magnetic material , wherein the soft magnetic material powder is a metal or alloy having an oxidized surface portion . In a communication cable having at least one cable core and a jacket containing an insulating material covering the cable core, a flat or needle is provided between the cable core and the jacket so as to cover the surface of the cable core. Jo soft magnetic powder composite magnetic layer made of an organic binding agent is configured, a communication cable, wherein the soft magnetic powder is a metal or alloy to oxidize the surface portion. In a communication cable having at least one cable core wire, a jacket including an insulating material covering the cable core wire, and a conductive sheet or knitted wire on the surface of the cable core wire , the cable core wire and the conductive wire Between the sheet or the braided wire, a composite magnetic material layer composed of a flat or needle-like soft magnetic powder and an organic binder is formed so as to cover the surface of the cable core wire, and the soft magnetic powder is a surface portion. A communication cable characterized by being an oxidized metal or alloy .

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