Multilayer Substrate Nonuniform GND Via Spacing Noise Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing multilayer substrates with nonuniformly spaced GND vias experience noise radiation due to undesired propagation modes, leading to noise generation in transmission lines.
Innovation Solution
A multilayer substrate design with specific arrangements of interlayer connection conductors and reference conductor layers, including a first opening in the second reference conductor layer, positioned to block undesired propagation modes and maintain uniform characteristic impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If multiple GND vias are spaced nonuniformly to electrically connect ground conductors, then the transmission line structure is simplified, but the characteristic impedance becomes nonuniform causing undesired propagation modes and noise radiation
Solution Approach 1:
The patent applies local quality by making the spacing between adjacent GND vias nonuniform in specific locations along the signal line. Instead of uniform spacing throughout, the distance varies at different positions to achieve desired impedance characteristics at critical sections while maintaining overall structural simplicity. This localized variation in spacing allows the transmission line to maintain proper impedance control where needed without requiring complete redesign of the entire via structure.
2Ease of manufacture
If GND vias are spaced widely to simplify structure, then manufacturing is easier, but undesired propagation modes occur between widely spaced vias causing noise radiation
Solution Approach 1:
The patent changes the spacing parameter between GND vias from a uniform value to a nonuniform distribution along the signal line. By varying the distance between adjacent vias at different positions, the design achieves better control over electromagnetic field distribution and impedance characteristics, thereby suppressing undesired propagation modes and reducing noise radiation while maintaining reasonable via spacing for manufacturability.
3Reliability
If uniform via spacing is used to maintain impedance uniformity, then noise radiation is reduced, but the transmission line structure becomes more complex
Solution Approach 1:
The patent implements local quality by applying nonuniform spacing only in specific sections where impedance control is critical, rather than making the entire via arrangement complex. The varying spacing is strategically positioned to address local impedance requirements while other sections maintain simpler patterns, thus achieving good overall impedance uniformity without excessive structural complexity throughout the entire transmission line.
Data Source
AI summary
In a multilayer substrate, one of a first reference conductor layer and a second reference conductor layer overlapping an eleventh interlayer connection conductor includes a first opening overlapping a signal conductor layer when viewed in a Z-axis direction. When viewed in the Z-axis direction, the first opening is positioned in a negative direction of an X axis relative to a vicinity of a first reference straight line connecting a second interlayer connection conductor and a fifth interlayer connection conductor. When viewed in the Z-axis direction, the first opening is positioned in a positive direction of the X axis relative to the eleventh interlayer connection conductor.