Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B11/00—Communication cables or conductors
  • H01B11/02—Cables with twisted pairs or quads
  • H01B11/06—Cables with twisted pairs or quads with means for reducing effects of electromagnetic or electrostatic disturbances, e.g. screens
  • H01B11/10—Screens specially adapted for reducing interference from external sources
  • H01B11/1033—Screens specially adapted for reducing interference from external sources composed of a wire-braided conductor

Definitions

• Cable shield made of fiber composite materials
• Cable shields are often used to shield electromagnetic fields and to prevent electromagnetic coupling within systems / platforms due to their great protective effect.
• the shields currently used for this are based on highly conductive metallic materials. Except when using special shielding materials (e.g. mu-metal), the damping behavior of these shields only begins in the upper kHz range and strives towards a finite damping value with increasing frequency.
• the umbrellas used are generally very heavy and therefore rather unsuitable especially for flying platforms.
• the invention relates to a device according to the preamble of claim 1.
• the electromagnetic shielding of system cabling proposed in this publication has the task
• the basic principle of the invention is that fiber composite materials with a high proportion of electrically conductive fibers (e.g. carbon fiber or metallized carbon fibers) are used as the shielding material.
• the so-called transfer impedance which allows the comparison of electrical properties of cable shields, is generally used as a measure of the shielding effect of a cable shield.
• the transfer impedance can be calculated from the following measured variables in a test setup in accordance with VG 95373 Part 15 (measurement method for coupling and shielding, KS01):
• This equation can be used when the wavelength is much larger than the cable shield length.
• a device according to claim 1 can be used to switch to cable shields made of fiber composite materials with a high proportion of electrically conductive fibers. In addition to the clear advantage of an almost negligible additional weight compared to the unshielded cable, this also gives the advantage of corrosion resistance.
• the screen made of fiber composite materials can be combined either with a metallic screen or with a screen with high relative permeability.
• the synthetic fibers could also be vapor-coated with appropriate ferromagnetic materials.
• This invention assumes that a semiconducting screen is applied directly to electrical conductors (especially to power cables), which is then surrounded by an insulation layer and an outer screen.
• the special chemical composition of the semiconducting screen offers the advantages of lower shrinkage behavior, lower water permeability, better processability compared to other semiconducting screens, and more favorable electrical properties.
• the semiconducting cable shield is applied directly to the conductor. The task of electromagnetic shielding cannot be achieved with this.
• the object of the invention in US Pat. No. 5,554,678 is to define composite materials which ensure electromagnetic shielding of housings for electronic devices.
• the goal here is to achieve good shielding effectiveness in low and high frequency ranges.
• This task is solved by a composite material, which consists of defined proportions of thermoplastics, conductive metal fibers and carbon fibers.
• basic physical properties of the carbon fibers or the carbon fiber-containing fiber composite materials are used, which are also important for the cable shields - the subject of the present invention.
• the object of this invention is the coating of metal surfaces for the absorption of electromagnetic waves (eg for radar camouflage) over a large frequency range. This is achieved on the basis of the invention by mixing a molecular, synthetic synthetic resin with highly conductive metal fibers and a ferromagnetic material. In contrast to the present invention, this is a highly rigid coating of surfaces for the absorption of electromagnetic waves, which cannot be used for a cable shield with the desired properties.
• Patent DE 195 45 559 AI
• the object of this invention is the interference suppression of electrical assemblies or circuits by sheathing with embedded absorber material made of ferrites or dielectrics with polarized particles.
• the present invention requires electrical conductivity of a non-metallic material and differs in that no absorber material in the form of a dielectric or in the form of ferrites is used.
• Patent DE / EP 0528 611 AI
• the object of this invention is the production of a conductor and cable article which offer protection against conducted signals on the line and emitted EMI (electromagnetic interference). This is achieved by using only a single layer of material consisting of spherical ferrite particles or shaped ferrite particles which are distributed within a polymeric binder / polymeric matrix (e.g. fluorocarbon, polymer).
• EMI electromagnetic interference
• This invention differs from the present invention in that neither spherical ferrite particles, shaped ferrite particles nor a polymeric matrix such as "fluorocarbon” or “acrylates” is used, but rather an electrically conductive non-magnetic material.
• the frequency range affected in the present invention differs significantly from that specified in invention DE / EP 0528 611 AI.
• the object of this invention is the elimination of cable vibrations / vibrations caused by periodic vibrations of the wires by their wire spacing and the associated inductive and capacitive undesirable changes in the line characteristic. This is achieved by introducing additional single lines made of non-metallic fiber (including carbon fiber) as a further strand element.
• This invention differs from the present invention in that the task of the non-metallic fibers is not electromagnetic damping, but rather they are used only as non-inductive spacers.
• the present invention there is an all-round sheathing of electrical lines Prerequisite for achieving electromagnetic damping.
• the metallic strands are followed by an insulation layer, over which the cable shield is finally applied.
• Patent DE 39 40 293
• the object of this invention is to create a ribbon cable, the outer conductive layer of which, compared to the prior art, has improved flexibility and conductivity. This is achieved by surrounding the ribbon cable made of several signal conductors with a screen made of non-conductive material, in which carbon fibers obtained from high-melting particles are distributed and coated with a metallic coating.
• This invention differs fundamentally from the present one in that no high-melting particles and no metallization are used in the present invention.
• the present invention is not limited to a strip conductor, but is applicable to any type of electrical conductor.
• Patent DE 38 780 22
• the object of this invention is the assembly of a cable shield jacket for protection against electromagnetic radiation from power cables in the low-frequency range ( ⁇ 100 kHz). This is achieved through the use of conventional metallic screens and assembly using a special screw connection and the use of multi-layer insulation.
• the present invention differs in that conductive, non-metallic materials are used as electromagnetic screens which can only be used for the high frequency range (> 1 MHz), both for power supplies and for any signal line or multiple line.
• Patent DE 34 38660
• the object of this invention is to improve a cable so that it can be manufactured and handled more easily. This will be achieved by one or more leads, each surrounded by an insulating material, from one common shielding layer is encased, which consists of a mixture of plastic with electrically conductive particles, preferably aluminum scales.
• This invention differs from the present invention in that instead of plastic with electrically conductive particles, only plastics without the addition of conductive particles (e.g. carbon fiber or non-metallic substances comparable in terms of conductivity) are used.
• plastics without the addition of conductive particles (e.g. carbon fiber or non-metallic substances comparable in terms of conductivity) are used.
• Metallic materials also serve as the basis for the cable shielding in the further claims 2 to 5, while the present invention relates only to non-metallic, electrically conductive substances.
• the object of the invention is to introduce the wiring with a everywhere cable shield in large and small systems with little additional weight to avoid electromagnetic coupling (within the system and from external fields) or to significantly improve the shielding behavior of metallic shields in the higher frequency range. This also ensures that no other weighty EMC protective measures with regard to radiated electromagnetic fields (be it radiation or radiation) are necessary.
• the weight reduction can either contribute to energy savings, to longer flight times (for flying platforms) or longer distances (for landing and water vehicles) or to higher speeds (for land vehicles and flying platforms). A deterioration in the system behavior with regard to the electromagnetic behavior due to aging or corrosion can be practically excluded by the invention.
• this object is achieved by a device having the features of claim 1, the ends of which are connected all around to the connector housings.
• this screen is covered in an exemplary form with an electrically insulating material (e.g. silicone).
• the area of use as an electromagnetic shield can be varied in a certain frequency range with regard to the lower limit frequency and the damping behavior, depending on the material required. In general, the damping behavior, as long as it is not combined with metallic shields, starts at a few MHz and then has a better behavior than metallic cable shields for higher frequencies.
• a cable shield according to claim 1 is sufficient; 2. If the entire frequency range is to be attenuated by the cable shield insert:
• a cable shield according to claim 2 can be used.
• Central advantages of the invention are a significantly higher shielding effect compared to conventional metallic shields in the higher frequency range and the weight reduction in systems without restriction / change in their electromagnetic behavior.
• the contact between the cable shield and the connector remains unchanged and cannot be negatively influenced by the formation of corrosion between the cable shield and the plug over the course of the years of use.
• Another advantage of the invention when using appropriate fiber materials is a high mechanical robustness (e.g. higher tensile strength) of the cable.
• the production of cables shielded with fiber composite materials requires less energy than metal shielded cables.
• Two-wire lines and coax cables can advantageously be designed so that, depending on the signal bandwidth to be transmitted, the lines can be designed so that the transmission loss is frequency-independent.
• FIG. 1 shows a twisted double conductor in which each of the two conductor fibers is surrounded by an electrical insulating layer and which is electromagnetically shielded by a carbon fiber braid impregnated with a rubber solution according to an exemplary embodiment for claim 3.
• FIG. 2 shows a line bundle which is electromagnetically shielded with a possibly metallized carbon fiber braid. An electrically insulating jacket is also drawn over this braid.
• FIG. 4 shows an example of a coaxial cable which consists of an inner conductor made of highly conductive metal and an outer conductor made of a carbon fiber braid.
• Figure 5 shows the cross section of a shielded single conductor according to claim 4.
• two electrically conductive sheaths (depending on the application, for example, a carbon fiber layer and a layer of ferromagnetic material) are applied in contact with each other. This double layer is separated from the metallic conductor in the center by an electrical insulator.

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• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Insulated Conductors (AREA)
• Communication Cables (AREA)

Applications Claiming Priority (3)

Publications (1)

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ID=7898504

Family Applications (1)

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• 1999
  • 1999-02-23 DE DE1999107675 patent/DE19907675A1/de not_active Ceased
• 2000
  • 2000-02-23 JP JP2000601658A patent/JP2002538581A/ja not_active Withdrawn
  • 2000-02-23 WO PCT/DE2000/000502 patent/WO2000051143A1/de not_active Application Discontinuation
  • 2000-02-23 EP EP00914037A patent/EP1163684A1/de not_active Withdrawn
  • 2000-02-23 BR BR0008412-3A patent/BR0008412A/pt not_active Application Discontinuation

Non-Patent Citations (1)

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