Coaxial Cable Air Layer Insulator Design
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Solution Overview
Problem
Conventional coaxial cables face issues with size reduction, high data transmission speeds, electromagnetic interference (EMI), low heat resistance, and manufacturing efficiency due to thin insulators and adhesion problems, as well as pinhole formation and short-circuiting from poorly spread insulating resins.
Innovation Solution
A coaxial cable design featuring a twisted electrically conductive filament body and an insulating yarn covered by a tubular insulator with an air layer, an outer conductor, and a sheath, which reduces permittivity, enhances flexibility, and increases manufacturing speed while minimizing pinholes and heat resistance issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the insulator is made thin to reduce cable diameter, then the cable diameter is reduced, but the adhesion between insulator and inner conductor becomes low causing the inner conductor to slip out
Solution Approach 1:
The insulator is constructed as a composite structure with a fluorocarbon resin base layer providing adhesion to the inner conductor, and a foamed fluorocarbon resin outer layer providing low permittivity. This composite approach allows the insulator to maintain both strong adhesion and low dielectric constant despite reduced thickness.
Solution Approach 2:
Different regions of the insulator have different properties: the inner layer adjacent to the inner conductor has high adhesion properties, while the outer layer has low permittivity properties. This local differentiation allows each region to fulfill its specific function while working together as a unified insulator structure.
2Quantity of substance
If foamed fluorocarbon resin tape is wrapped around the inner conductor to form the insulator, then the permittivity is reduced, but the adhesion becomes low and manufacturing line speed cannot be increased
Solution Approach 1:
The insulator structure changes from a single homogeneous material to a layered composite with different densities and permittivity values. The foamed outer layer provides low permittivity while the solid inner layer ensures adhesion, allowing high-speed manufacturing without compromising electrical properties.
Solution Approach 2:
The insulator is segmented into two distinct layers with different functions: the inner solid layer for adhesion and the outer foamed layer for low permittivity. This segmentation allows each layer to be optimized independently for its specific purpose while maintaining compatibility in the overall structure.
3Ease of manufacture
If adhesive-coated polyester tape is used as binding tape, then the cable can be assembled, but the tape contracts by heat during soldering causing the insulator to be exposed
Solution Approach 1:
The binding tape is selected to have low thermal contraction properties, ensuring that during the soldering process and subsequent heating, the tape maintains its dimensional stability and continues to cover the insulator properly without exposing it.
Solution Approach 2:
Instead of relying on adhesive-coated polyester tape that degrades under heat, the invention uses heat-resistant binding materials that maintain their structural integrity throughout the manufacturing process and product lifecycle, eliminating the need for re-binding or additional protective measures.
4Volume of moving object
If the insulating tube is thinly formed to reduce cable size, then the cable diameter is reduced, but the insulating tube readily breaks to form pinholes causing short-circuiting
Solution Approach 1:
The insulator uses a composite structure where the solid inner layer provides mechanical strength and pinhole resistance, while the foamed outer layer provides low permittivity. This allows thin-wall construction without sacrificing structural integrity or electrical performance.
Solution Approach 2:
The insulator structure provides different properties at different locations: the inner layer adjacent to conductors provides mechanical strength and defect resistance, while the outer layer provides electrical optimization. This local differentiation enables thin overall thickness without compromising reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution results in a coaxial cable with lower dielectric loss, improved heat resistance, and increased manufacturing efficiency, achieving the same performance as foamed fluorocarbon resin cables with less expensive materials and a smaller diameter, while reducing pinholes and improving handling and bending resistance.
Implementation Method 1
a low-permittivity insulator containing an air layer
Data Source
AI summary
A coaxial cable and multi-coaxial cable which comprise a low-permittivity insulator having an air layer, whose outer diameters can be reduced, which have excellent flexibility, and which allow productivity to be increased. In the coaxial cable, an electrically conductive filament body for forming an inner conductor, and a filling yarn made of an electrically insulating resin are twisted together, the outside of this twisted body is covered with a tubular insulator so that the insulator makes contact with the electrically conductive filament body and the filling yarn. An outer conductor is provided to the external periphery of the insulator. The multi-coaxial cable has a plurality of the coaxial cables, and the coaxial cables are covered with a common sheath composed of an insulating material.