Shielded Parallel Cable With Checkerboard Adhesive
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Solution Overview
Problem
Shielded parallel pair cables experience signal loss due to discontinuities in the helical shield, leading to increased attenuation and skew, which hinders low insertion loss performance in high-speed data transmission applications.
Innovation Solution
The cable design includes a pair of insulated conductors and an optional drain wire, wrapped longitudinally with a metallic shielding tape having an adhesive in a checkerboard pattern, and covered with two layers of polymeric tapes spirally wrapped in opposite directions to minimize shield discontinuities and reduce insertion loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a helically wrapped shield is used to shield the cable, then the cable provides electromagnetic shielding, but the helical shield creates discontinuities that cause signal loss and increased attenuation
Solution Approach 1:
The shield is segmented into multiple individual foil strips wrapped in different directions rather than a single continuous helical wrap. This segmentation allows each strip to be optimized for specific shielding directions while maintaining overall shield continuity through proper overlap and positioning, reducing signal loss at discontinuity points
Solution Approach 2:
Different sections of the shield have different wrapping directions and configurations tailored to local electromagnetic interference patterns. The shield structure varies locally to provide optimal protection against different types of interference while maintaining signal integrity in each specific region
2Device complexity
If a helically wrapped shield is used, then the cable structure is simplified, but skew increases due to shield discontinuities
Solution Approach 1:
The shield is divided into multiple independent foil strips wrapped in opposite directions. This segmentation creates a more complex structure that actually reduces skew by eliminating the systematic discontinuities inherent in single-direction helical wraps, as the opposite-direction strips compensate for each other's discontinuities
Solution Approach 2:
The shield uses asymmetric wrapping patterns with strips going in opposite directions rather than a symmetric single-direction helix. This asymmetry disrupts the systematic error patterns that cause skew in traditional helical shields, providing more uniform signal characteristics
3Ease of manufacture
If traditional spiral wrapped shielding tape is used, then manufacturing is simpler, but insertion loss increases due to shield discontinuities
Solution Approach 1:
Rather than applying one continuous spiral wrap, the shield is created by applying multiple segmented foil strips in opposite directions. This segmented approach requires slightly more complex manufacturing but eliminates the severe discontinuities of traditional spiral wraps, achieving low insertion loss performance
Solution Approach 2:
The shield maintains continuous electromagnetic protection by ensuring overlapping edges and proper positioning of adjacent foil strips. This continuity of shielding action eliminates the gaps and discontinuities in traditional helical shields, maintaining signal integrity throughout the cable length
Data Source
AI summary
The cable of the present invention contains at least one pair of insulated conductors and an optional drain wire. The insulate conductors and drain wire is longitudinally covered in a shielding tape, which preferably comprises a metallic sheet having an adhesive applied on selected portions of a surface of the metallic sheet. The adhesive is preferably applied in a checker board pattern so that the surface having adhesive thereon contains areas of uncoated, exposed metal forming contact pads. The shielding tape is then covered with two layers of polymeric tapes in opposite helical directions. The polymeric tape is preferably constructed of a polymeric sheet having a layer of adhesive disposed on a surface thereof. In a preferred embodiment, the tapes are wrapped around the shielding tape in opposite directions such that the adhesive surfaces face each other. The tapes are then optionally covered with a jacket.