Shielded Backplane Connector Layout for High-Speed Crosstalk Isolation
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Solution Overview
Problem
Conventional backplane connectors face excessive crosstalk noise, which cannot meet the high-speed electrical performance requirements for communication products evolving to 56 Gbps or 112 Gbps, particularly in terms of crosstalk, loss, and reflection.
Innovation Solution
A connector design featuring stacked lead frames with shield layers and end protectors that include conductive and shield structures to electromagnetically isolate connection terminal groups, utilizing air as a dielectric to reduce dielectric loss and enhance electromagnetic isolation, thereby improving signal transmission paths and reducing crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional backplane connector design is used, then device complexity is reduced, but crosstalk noise becomes excessive and cannot meet high-speed electrical performance requirements
Solution Approach 1:
The connector is divided into multiple lead frames stacked in the first direction, with each lead frame containing connection terminal groups and shield layers. This segmentation allows for improved electromagnetic isolation between signal paths while maintaining a manageable structural complexity through modular design.
Solution Approach 2:
Shield layers are introduced as intermediary elements between adjacent connection terminal groups in stacked lead frames. These shield layers act as electromagnetic barriers that isolate signal paths and reduce crosstalk noise, serving as mediators that prevent harmful electromagnetic coupling between adjacent signals.
2Reliability
If shield layers and conductive structures are added to reduce crosstalk, then electromagnetic isolation is improved, but manufacturing complexity increases
Solution Approach 1:
The end protector is designed to integrate multiple functions: it provides mechanical protection for connection terminals, establishes electrical connection to the ground layer, and incorporates conductive structures that transfer loop signals. This merging of functions reduces the number of separate components needed and simplifies the manufacturing process while maintaining reliable electromagnetic isolation.
Solution Approach 2:
The shield layers serve multiple purposes: they provide electromagnetic isolation between adjacent connection terminal groups, establish reference potentials for signal integrity, and contribute to the overall structural framework of the connector. This multi-functionality reduces the need for additional dedicated components, thereby easing manufacturing complexity.
3Object-affected harmful factors
If stacked lead frames with shield layers are used, then crosstalk is reduced, but device complexity increases
Solution Approach 1:
The connector transitions from a planar arrangement to a three-dimensional stacked configuration with lead frames arranged in the first direction. This dimensional change allows shield layers to be positioned between adjacent connection terminal groups in the vertical dimension, providing effective electromagnetic isolation without requiring excessive lateral space or complex lateral shielding structures.
Solution Approach 2:
Multiple lead frames are stacked and nested in the first direction, with each lead frame containing connection terminal groups and embedded shield layers. This nested arrangement allows compact integration of multiple signaling paths with intermediate shielding, reducing crosstalk while maintaining a space-efficient design that avoids excessive device complexity.
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 design significantly reduces crosstalk and insertion loss, meeting the requirements for high-speed communication applications by improving electrical and electromagnetic isolation, with crosstalk performance enhanced by at least 10 dB in certain frequency bands.
Implementation Method 1
The shield layer is configured to electromagnetically isolate connection terminal groups in adjacent lead frames
Implementation Method 2
The conductive structure is electrically connected to the corresponding shield layer, such that a loop signal corresponding to the differential signal is transferred from the ground layer of the circuit board to the shield layer through the conductive structure
Implementation Method 3
utilizing air as a dielectric to reduce dielectric loss
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A connector (6), a functional board, and a board-level architecture are provided. The connector (6) includes an end protector (30) and a lead frame (20). Each lead frame (20) includes a plurality of connection terminal groups (22) and a shield layer (21 or 23). Each connection terminal group (22) includes two connection terminals (221 and 222) configured to transmit a signal. Each connection terminal (221 or 222) has a first connection end that helps with insertion of a circuit board (5). The shield layer (21 or 23) is configured to electromagnetically isolate connection terminal groups (22) in adjacent lead frames (20). The end protector (30) includes a conductive structure (32) that is located between the first connection ends of the two connection terminals (221 and 222) in each connection terminal group (22). The conductive structure (32) is electrically connected to the corresponding shield layer (21 or 23) of the connection terminal group (22), and is configured to transmit a loop signal corresponding to the differential signal. In the foregoing technical solution, with the conductive structure (32) that is on the end protector (30), a transmission path of a loop signal corresponding to a differential signal transmitted by each connection terminal group (22) is improved, reducing crosstalk between loop signals corresponding to different connection terminal groups (22), and improving a communication effect of the connector.