Card Edge Connector Grounding Plate Signal Integrity
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Solution Overview
Problem
Existing card edge connectors fail to meet high-speed requirements and effectively address electromagnetic interference (EMI) and signal integrity issues such as insertion loss, return loss, and cross-talk.
Innovation Solution
A card edge connector design featuring an insulative housing with first and second terminals, and a grounding and shielding plate that electrically connects to all grounding terminals, improving signal integrity and EMI shielding through a combination of elastic and leg portions, and grounding fingers that deform to establish connections with a one-piece metal grounding plate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple card edge connector structure is used, then the device complexity is reduced and manufacturing is easier, but signal integrity deteriorates due to resonance, insertion loss, return loss, and cross-talk at high speeds
Solution Approach 1:
A grounding and shielding plate is introduced as an intermediary component between the connector and the external environment. This plate serves dual functions: providing a reference ground plane that reduces resonance and insertion loss, and shielding the signal terminals from electromagnetic interference that causes cross-talk. The plate connects to all grounding terminals through leg portions, creating a stable electromagnetic reference without complicating the basic connector structure.
Solution Approach 2:
The grounding and shielding plate modifies the electromagnetic parameters of the connector system by introducing a continuous ground reference plane. This changes the impedance characteristics, reducing return loss and preventing resonance effects. The plate's presence fundamentally alters the electromagnetic field distribution, eliminating cross-talk between adjacent signal terminals while maintaining the simple mechanical structure of the connector.
2Device complexity
If traditional grounding methods are used, then the device complexity remains low, but electromagnetic interference shielding is insufficient
Solution Approach 1:
The grounding and shielding functions are merged into a single integrated plate structure. This combined plate simultaneously provides the ground reference needed for signal integrity and the electromagnetic shielding required to block external interference. By merging these functions, the design achieves effective EMI protection without adding separate complex grounding structures or shielding enclosures.
Solution Approach 2:
The grounding and shielding plate performs multiple functions: it serves as a ground reference plane, provides electromagnetic shielding, and structurally supports the connector assembly. The plate's multi-functionality allows it to address EMI issues comprehensively while maintaining simplicity in the overall device design, avoiding the need for separate grounding wires, shields, or ferrite beads.
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
The solution enhances signal integrity by reducing resonance, insertion loss, return loss, and cross-talk, while effectively shielding against electromagnetic interference, thereby improving overall performance.
Implementation Method 1
each second terminal including an upright portion, an elastic portion extending from the upright portion with a contacting portion exposed upon the card slot, and a leg portion
Implementation Method 2
a grounding and shielding plate. The row of second terminals comprises signal terminals and grounding terminals... The grounding and shielding plate covers the rear face of the insulative housing and electrically connects to all the grounding terminals of the row of second terminals
Data Source
AI summary
A card edge connector includes an insulative housing defining a front face, a rear face, and a card slot opening forward through the front face, a row of first terminals retained in the insulative housing from the front face, a row of second terminals retained in the insulative housing from the rear face, and a grounding and shielding plate. The row of second terminals includes signal terminals and grounding terminals, each second terminal including an upright portion, an elastic portion extending from the upright portion with a contacting portion exposed upon the card slot, and a leg portion. The grounding and shielding plate covers the rear face of the insulative housing and electrical connects to all the grounding terminals of the row of second terminals.