Broadside-Coupled Via FEXT Cancellation in Connectors
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Solution Overview
Problem
Current methods for reducing Far-End Crosstalk (FEXT) in electrical connectors and plated through holes, particularly in high-frequency systems, are insufficient and often require increased space and complexity, leading to design difficulties and limited effectiveness.
Innovation Solution
The approach involves manipulating the geometry and location of differential pairs to achieve either positive or negative polarity in FEXT coupling, utilizing broadside-coupled and edge-coupled structures to create opposing polarities, which can be applied in chip packages, connectors, and PCBs, thereby reducing cumulative differential FEXT.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional FEXT reduction methods (increasing spacing, adding ground between differential pairs, tightening coupling) are used, then FEXT is reduced to some extent, but real estate consumption increases and design complexity increases
Solution Approach 1:
The patent changes the coupling configuration parameter from traditional edge-coupling to broadside-coupling, where signal vias are arranged with one via directly above the other on adjacent layers. This parameter change in via arrangement creates opposite polarity FEXT that cancels cumulative FEXT, achieving FEXT reduction without increasing spacing or adding ground vias, thus not consuming additional real estate.
Solution Approach 2:
The patent converts the harmful cumulative FEXT effect into a beneficial cancellation effect by deliberately creating opposite polarity FEXT through broadside-coupled via arrangements. The harmful electromagnetic coupling between adjacent differential pairs is transformed into a useful cancellation mechanism where FEXT from different coupling points has opposite polarities that subtract from each other.
2Object-affected harmful factors
If traditional FEXT reduction methods (adding ground vias, increasing spacing) are used, then FEXT is reduced, but device complexity and implementation difficulty increase
Solution Approach 1:
The patent simplifies the design by changing the via coupling parameter to broadside-coupling, which inherently produces opposite polarity FEXT. This eliminates the need for complex ground via arrangements or asymmetric via spacing calculations, reducing implementation difficulty while maintaining FEXT reduction effectiveness.
Solution Approach 2:
The patent converts the complex problem of managing cumulative FEXT into a simple solution where broadside-coupled vias automatically generate opposite polarity FEXT that cancels the harmful effect. This transforms a complex FEXT management problem into an automatic cancellation mechanism through simple via arrangement.
3Object-affected harmful factors
If traditional FEXT reduction methods are used in high-frequency systems, then some FEXT reduction is achieved, but cumulative total FEXT remains significant
Solution Approach 1:
The patent addresses high-frequency cumulative FEXT by changing the spatial arrangement parameter to broadside-coupling, where signal vias are positioned directly above each other on adjacent layers. This creates opposite polarity FEXT that cancels cumulative effects, achieving superior FEXT reduction effectiveness in high-frequency differential signaling systems compared to traditional methods.
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 method effectively reduces FEXT by optimizing the polarity of differential coupling, allowing for fewer ground vias and improved space efficiency, stable power distribution, and reduced noise in high-speed data transmission systems.
Implementation Method 1
balancing capacitive and inductive coupling
Implementation Method 2
balancing capacitive and inductive coupling
Data Source
AI summary
Systems, methods and apparatuses involving a chip-to-chip communication channel, for reducing Far End Crosstalk (FEXT) through the novel concept of controlling FEXT magnitude and polarity of a component inside a channel, vias or within a connector by implementing broadside and edge couplings to offset cumulative FEXT in a channel, via-connector-via subsystem or a connector. The example implementations described herein can be applied to a chip-to-chip communication channel, mezzanine connectors, backplane connectors and any other connectors requiring via routing, and connector itself that can benefit from FEXT reduction.