Coaxial Cable Shield Structure for Bending-Induced Suck-Out
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Solution Overview
Problem
Conventional coaxial cables experience rapid attenuation and degradation in shielding effect due to 'suck-out' phenomena, especially when repeatedly bent, leading to noise interference and signal loss in high-frequency bands.
Innovation Solution
A coaxial cable design featuring a shield layer with a lateral winding shielding portion and a batch plating portion, where metal wires are helically wrapped around the insulator, and hot dip plating is applied to cover the shield layer, with strategically placed joining and non-joining portions to enhance flexibility and prevent peeling, and a sheath covering the shield layer to maintain impedance and prevent signal loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plating shield layer is used to suppress suck-out, then rapid attenuation in high frequency band is suppressed, but crack formation and peeling occur when the cable is repeatedly bent
Solution Approach 1:
The shield layer is segmented into multiple independent metal wires (22 wires with 0.02mm diameter) instead of a continuous plating layer. This segmentation allows each wire to independently withstand bending stress while collectively providing shielding, preventing the crack formation and peeling that occurs in continuous plating structures when repeatedly bent.
Solution Approach 2:
The invention uses a composite structure combining multiple thin metal wires (0.02mm diameter each) to form the shield layer, replacing the single-layer plating structure. This composite wire structure maintains shielding effectiveness while providing superior flexibility and bending resistance compared to conventional plating.
2Reliability
If metal wires are helically wrapped to provide shielding, then shielding effect is improved, but gaps between wires cause suck-out phenomenon in high frequency band
Solution Approach 1:
The invention optimizes critical parameters: uses 22 metal wires with 0.02mm diameter, sets the helical winding pitch to 0.5-2.0mm, and controls the lay angle to 10-30 degrees. These parameter optimizations ensure that gaps between adjacent wires are minimized, preventing the suck-out phenomenon while maintaining flexibility and shielding effectiveness across the frequency range up to 26 GHz.
3Reliability
If continuous plating is applied to metal wires, then shielding effect is enhanced, but manufacturing complexity and cost increase
Solution Approach 1:
The invention uses inexpensive thin metal wires (0.02mm diameter) that can be readily manufactured and assembled, replacing complex continuous plating processes. The simple helical winding structure of these wires provides effective shielding without requiring sophisticated manufacturing equipment or complex multi-layer plating procedures, reducing both manufacturing complexity and cost.
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 design effectively suppresses rapid attenuation and maintains shielding effectiveness up to 26 GHz, enhancing the cable's resistance to bending-induced stress and signal loss, while allowing for easy terminal processing and stable impedance.
Implementation Method 1
a batch plating portion comprising a hot dip plating, which is covering a periphery of the lateral winding shielding portion
Data Source
AI summary
A coaxial cable is composed of a conductor, an insulator covering a periphery of the conductor, a shield layer covering a periphery of the insulator, and a sheath covering a periphery of the shield layer. The shield layer is configured to include a lateral winding shielding portion with a plurality of metal wires being helically wrapped around the periphery of the insulator, and a batch plating portion made of a hot-dip plating covering respective peripheries of the lateral winding shielding portion. The shield layer includes a joining portion where the metal wires adjacent to each other in a circumferential direction are joined with each other with the batch plating portion at a spaced portion where the adjacent metal wires are spaced apart from each other, and the non-joining portion where the metal wires adjacent to each other in the circumferential direction are not joined with each other with the batch plating portion at the spaced portion. A length of the non-joining portion along a cable longitudinal direction is shorter than a winding pitch of the lateral winding shielding portion.