SFP Connector Impedance Matching via Shaped Contacts and Lossy Bridges
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Solution Overview
Problem
Standardized electrical connectors, such as SFP connectors, face limitations in electrical performance due to constrained form factors, which restrict design options and impedance matching with printed circuit boards and cables, leading to suboptimal high-speed signal transmission.
Innovation Solution
The use of shaped conductive elements and bridging members made of lossy materials within the connectors to optimize impedance matching and reduce electrical resonances, allowing for improved high-frequency performance without altering the connector's form factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If standardized form factor is maintained, then connector compatibility and ease of manufacture are improved, but electrical performance and impedance matching deteriorate
Solution Approach 1:
The patent applies local quality by making the intermediate portion of contact elements narrower than other portions, creating a localized impedance transformation region. This narrow section is positioned specifically to match impedance between the contact element and printed circuit board, while maintaining standardized mating portions for compatibility. The lossy material is also applied locally at specific positions within the connector housing to dampen resonances without affecting overall connector dimensions.
Solution Approach 2:
The patent changes geometric parameters of the contact elements, specifically making the intermediate portion narrower than the mating portion and contact tail. This parameter change creates an impedance transformation that improves high-frequency signal transmission. The cross-sectional area of the intermediate portion is deliberately reduced to achieve impedance matching, while other dimensions remain consistent with standardized form factors.
2Reliability
If contact elements are made narrower for impedance matching, then high-frequency signal transmission is improved, but mechanical strength and ease of manufacture worsen
Solution Approach 1:
The contact element is segmented into three distinct portions with different cross-sectional areas: a wider contact tail for mechanical strength and soldering, a narrow intermediate portion for impedance matching, and a standard-width mating portion for compatibility. This segmentation allows each section to be optimized for its specific function without compromising overall structural integrity.
Solution Approach 2:
The patent transitions from a uniform cross-section to a varying cross-section along the length of the contact element. By changing the dimension in the longitudinal direction (creating a tapered or stepped profile), the patent achieves impedance matching while maintaining sufficient mechanical strength through the wider contact tail and standard mating portion.
3Reliability
If lossy material is added to reduce resonances, then electrical performance is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts the resonance damping function from the main contact element structure and implements it through a separate lossy material component positioned within the connector housing. This lossy material is placed at specific locations to dampen resonances without requiring modification of the contact elements themselves, thereby reducing overall device complexity.
Solution Approach 2:
The lossy material acts as an intermediary element that absorbs electromagnetic energy and dampens resonances between the contact elements and housing. This intermediary component simplifies the overall design by providing a dedicated solution for resonance control without requiring complex modifications to the signal path structures.
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 approach enhances the frequency range and reduces insertion loss, achieving common mode and differential mode impedances that match printed circuit boards and cables, thereby improving the overall electrical performance of the connectors.
Implementation Method 1
bridging members made of lossy materials within the connectors to optimize impedance matching and reduce electrical resonances
Data Source
AI summary
Techniques for improving electrical performance of a connector. The techniques are compatible with the form factor of a standardized connector, such as an SFP connector or stacked SFP. The resulting connector has reduced insertion loss for high speed signals. Such techniques, which can be used separately or together, include shaping of conductive elements within the connector while still retaining the same mating contact arrangement. Changes may be made at the contact tail portions or in the intermediate portions where engagement to a connector housing occurs. The techniques also include the incorporation of lossy bridging members between conductive elements designated to be ground conductors. For connectors according to the stacked SFP configuration, multiple bridging members may be incorporated at multiple locations within the connector.