Connector Shielding for 100 Ohm Impedance Match
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Solution Overview
Problem
The existing H-MTD® connector system for high-speed data transmission in automotive and multi-GHz applications faces challenges in achieving a differential impedance match close to 100Ω, necessitating improved shielding to enhance signal integrity and reduce interference.
Innovation Solution
The proposed solution involves a connector assembly with both an inner and outer shield, forming an 'EMC-labyrinth' configuration, where the outer shield partially surrounds the inner shield, and embossments are used to enhance electrical contact and impedance matching, ensuring effective shielding and signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If only an inner shield is used in the connector, then the connector structure remains simple, but the shielding effectiveness is insufficient to achieve a differential impedance match close to 100Ω
Solution Approach 1:
The patent implements a nested shielding structure where an outer shield contains an inner shield, with both shields surrounding the signal wires. The outer shield has a first shielding portion and a second shielding portion, while the inner shield is positioned within the outer shield's enclosure. This nested configuration enhances shielding effectiveness and achieves the required differential impedance match without excessive complexity.
2Reliability
If the inner shield completely surrounds the wires, then shielding is improved, but gaps in the shield perimeter can still allow interference signals
Solution Approach 1:
The patent introduces a second shielding portion in the outer shield that acts as an intermediary barrier. This second shielding portion is positioned to overlap with the first shielding portion, creating a layered defense that blocks interference signals from penetrating through gaps in the inner shield. The overlapping configuration ensures continuous shielding coverage.
3Speed
If the connector is designed for high-speed data transmission up to 20 Gbps, then data transmission capability is improved, but maintaining differential impedance match becomes more difficult
Solution Approach 1:
The patent optimizes geometric parameters of the shielding structure, including the dimensions and positioning of the outer and inner shields, to achieve the required differential impedance match of close to 100Ω. The outer shield's first and second shielding portions are configured with specific dimensions and spacing to control electromagnetic field distribution, enabling high-speed data transmission up to 20 Gbps while maintaining impedance matching.
Data Source
AI summary
Assembly comprising a cable having at least two signal wires, and a connector connected to the shielded cable, wherein the connector comprises at least two elongated inner signal contacts each connected to a wire of the cable, wherein the connector comprises a shielding portion formed of an inner shield and an outer shield, and wherein the inner shield at least approximately completely surrounds the wires of the cable and the outer shield at least partially surrounds the inner shield.