Shielded Wire Terminal Structure for Impedance-Matched Connections
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Solution Overview
Problem
The stripping of shielding foil and sheath at the end of shielded electric wires to connect terminals leads to impedance changes, causing signal reflection and reduced communication quality.
Innovation Solution
An electric wire configuration with a shielded wire and terminal, where the uncovered portion is covered with an impedance adjustment member having electric conductive properties, which extends to match the impedance of the covered wire, and a terminal module with an impedance adjustment member that adjusts the distance between covered wires to match terminal spacing, preventing impedance changes and ensuring correct positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the shielding foil and sheath are stripped at the end of the shielded electric wire to connect terminals, then the terminals can be electrically connected to the covered wires, but the impedance changes at the uncovered portion causing signal reflection and reduced communication quality
Solution Approach 1:
An impedance adjustment member is introduced as an intermediary component between the covered wire and the uncovered portion. This member has a gradual impedance transition from the impedance of the covered wire to the impedance of the uncovered portion, preventing abrupt impedance changes and signal reflection while allowing terminal connection.
Solution Approach 2:
The impedance adjustment member utilizes gradual parameter changes in its structure, specifically varying the width of the conductive portion along its length. The width transitions from matching the covered wire diameter to being smaller, creating a gradual impedance transition that maintains signal integrity during the uncovered portion.
2Ease of operation
If the uncovered portion is left without covering to enable terminal connection, then the terminal can be installed, but the impedance mismatch causes signal reflection
Solution Approach 1:
The impedance adjustment member serves as a mediator between the covered wire and the uncovered portion, providing a gradual impedance transition that eliminates the abrupt impedance mismatch. This prevents signal reflection while allowing the uncovered portion to remain exposed for terminal installation.
Solution Approach 2:
The impedance adjustment member applies local quality changes by having its conductive portion width vary along its length. The width is larger near the covered wire and gradually decreases toward the uncovered portion, creating localized impedance adjustments that prevent signal reflection at each position.
3Reliability
If an impedance adjustment member is added to cover the uncovered portion, then impedance consistency is maintained, but the device complexity increases
Solution Approach 1:
The impedance adjustment member is merged with the existing wire structure by being formed as an integral part of the wire assembly during manufacturing. This combining of the impedance adjustment function with the wire structure reduces the number of separate components and simplifies the overall device complexity.
Solution Approach 2:
The impedance adjustment member serves multiple functions: it provides impedance transition, acts as a protective layer during assembly, and maintains mechanical strength. This multi-functionality reduces the need for additional separate components, thereby reducing device complexity while maintaining impedance consistency.
Data Source
AI summary
An electric wire with a terminal described herein includes a shielded electric wire 11 and an inner conductive member 20. The shielded electric wire 11 includes a covered wire 12 including a core wire 13 through which a signal for communication is transmitted and an insulation cover 14 that has insulation property and covers the core wire 13, a shielding portion 15 having electric conductive property and covering an outer periphery of the covered wire 12, and a sheath 16 covering an outer periphery of the shielding portion 15. The inner conductive member 20 is connected to the covered wire 12. The covered wire 12 has an end portion close to the inner conductive member 20 and the end portion is an uncovered portion 17 that is not covered with the sheath 16 and the shielding portion 15. The uncovered portion 17 is covered with an impedance adjustment member 80 that has electric conductive property.