Shielded Flat Cable Impedance Consistency
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Solution Overview
Problem
Shielded flat cables experience inconsistency in characteristic impedance between terminal and non-terminal parts, affecting transmission quality, especially during high-speed signal transmission.
Innovation Solution
A shielded flat cable design featuring conductors with parallel surfaces covered by insulators and a metal shield member via a resin layer, which extends to the exposed surface, ensuring consistent impedance and improved shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conductors are exposed at the terminal part for electrical connection to the connector, then ease of connection is improved, but characteristic impedance consistency deteriorates
Solution Approach 1:
The shield member is designed to extend specifically to the exposed surface of the conductor at the terminal part, creating a localized shielding structure. This local extension maintains characteristic impedance consistency at the critical connection point while preserving the exposed conductor surface for electrical connection. The shield member's selective positioning addresses the impedance issue only where needed without compromising connection ease.
Solution Approach 2:
The shield member acts as an intermediary structure between the exposed conductor surface and the external environment. By extending to the exposed surface, it provides a gradual transition for electromagnetic fields, reducing impedance discontinuity while allowing the conductor to remain exposed for connection purposes. This intermediary structure mediates between the conflicting requirements of connection accessibility and impedance consistency.
2Object-affected harmful factors
If a shield member is provided to avoid external noise effects, then noise shielding is improved, but characteristic impedance inconsistency at the terminal part worsens
Solution Approach 1:
The shield member extends locally to the exposed surface at the terminal part rather than uniformly along the entire conductor length. This localized extension provides noise shielding precisely where the exposed conductor is most vulnerable to external interference, while maintaining characteristic impedance consistency at the critical connection point. The selective positioning optimizes both shielding effectiveness and impedance matching.
Solution Approach 2:
The shield member is configured to extend in the longitudinal direction to reach the exposed surface, adding a dimensional aspect to the shielding structure. This longitudinal extension creates a three-dimensional shielding configuration that addresses impedance inconsistency at the terminal part while maintaining overall noise protection. The dimensional change allows the shield to function effectively at the critical interface region.
Data Source
AI summary
A shielded flat cable includes conductors arranged parallel to each other and respectively having a first surface and a second surface opposite to the first surface, a first insulator provided on the first surface of each of the conductors, and a second insulator provided on the second surface of each of the conductors. The first surface of each of the conductors includes an exposed surface at an end part along a longitudinal direction. The shielded flat cable further includes a shield member that includes a metal layer and is configured to cover the first insulator and a portion of the exposed surface of the first surface, via a resin layer.