Shielded Electrical Cable Asymmetric Void Compensation
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Solution Overview
Problem
Shielded electrical cables experience signal skew due to air voids created by the overlapping cable shield, which affects the effective dielectric constant and capacitance of the conductors, leading to imbalanced signal transmission in differential pairs.
Innovation Solution
The cable shield is designed to form a void closer to one conductor than the other, with the affected conductor being shifted closer to the cable shield to increase its capacitance and compensate for the reduced effective dielectric constant, thereby mitigating skew imbalance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a cable shield is wrapped around the conductor assembly, then electromagnetic shielding is improved, but air voids are created at the overlap region causing signal skew
Solution Approach 1:
The patent applies asymmetry by intentionally creating an air void at a specific location (on one side of the differential pair) rather than attempting to eliminate all voids symmetrically. This asymmetric void placement, combined with shifting one conductor closer to the shield, creates balanced capacitance values for both conductors despite the presence of the void, thereby resolving the signal skew problem while maintaining the shielded structure
Solution Approach 2:
The patent applies local quality by modifying the cable structure only in the specific region where the air void exists. Instead of redesigning the entire cable, the invention locally adjusts the position of one conductor relative to the shield to compensate for the void's effect, changing the local capacitance distribution to achieve overall signal balance
2Reliability
If the cable shield overlaps itself, then continuous shielding is achieved, but the effective dielectric constant changes causing capacitance imbalance
Solution Approach 1:
The patent converts the harmful effect of the air void (which changes the dielectric constant and causes capacitance imbalance) into a beneficial outcome. By intentionally positioning the void and compensating through conductor placement, the invention uses the void's dielectric effect to adjust capacitance values, transforming a manufacturing defect into a design feature that achieves signal balance
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
This design enhances signal integrity by balancing the signal speed across both conductors, achieving near-zero skew and improved performance in high-speed data transmission applications.
Implementation Method 1
a void is created that is filled with air, which has a different dielectric constant than the material of the insulator and shifts the cable shield farther from the signal conductor
Implementation Method 2
The first conductor is shifted closer to the cable shield a shift distance compared to the second conductor to increase capacitance of the first conductor compared to the second conductor
Data Source
AI summary
An electrical cable includes a conductor assembly having a first conductor, a second conductor, and an insulator structure surrounding the first conductor and the second conductor. The first and second conductors carry differential signals. The insulator structure has an outer surface. A cable shield is wrapped around the conductor assembly and engages the outer surface of the insulator structure. The cable shield has an inner edge and a flap covering the inner edge. The cable shield forms a void at the inner edge being located closer to the first conductor than the second conductor. The air void compromising the first conductor by reducing an effective dielectric constant surrounding the first conductor. The first conductor is shifted closer to the cable shield a shift distance compared to the second conductor to increase capacitance of the first conductor compared to the second conductor.