Segmented PCB Through Connections for Impedance Matching
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Solution Overview
Problem
Conventional printed circuit boards face challenges in maintaining signal integrity due to impedance discontinuities at through connections, particularly in high-speed signal transmission, as they lack flexibility in adjusting impedance after manufacturing.
Innovation Solution
The printed circuit board features segmented through connections with dielectric columns separating wall segments, allowing for adjustable impedance matching by determining segment sizes based on transmission path requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional through connections are used in multi-layer PCBs, then signal transmission between routing layers is enabled, but impedance discontinuity occurs causing signal reflection and attenuation
Solution Approach 1:
The through connection is divided into multiple separate wall segments instead of being a continuous metal structure. These segments are arranged at different angular positions around the through hole perimeter, creating a segmented configuration that reduces impedance discontinuity while maintaining electrical connectivity between layers.
Solution Approach 2:
Different wall segments are positioned at specific angular locations to optimize impedance matching at critical points. The non-uniform distribution of wall segments creates localized impedance characteristics that match the transmission line requirements, reducing signal reflection and improving signal integrity.
2Ease of manufacture
If conventional through connections with uniform dimensions are used, then manufacturing is simplified, but impedance matching flexibility is limited after PCB fabrication
Solution Approach 1:
By segmenting the through connection into separate wall portions, the design enables post-fabrication impedance optimization without requiring complete redesign of the through connection structure. Each segment can be independently adjusted or positioned to achieve desired impedance characteristics.
Solution Approach 2:
The segmented structure provides dynamic adjustability in impedance characteristics after the PCB is manufactured. The separation of wall segments allows for flexible configuration to match different impedance requirements of transmission lines without changing the basic through hole geometry.
3Reliability
If the through connection dimension is increased to improve signal integrity, then impedance matching improves, but the through connection interferes with other dimensional requirements
Solution Approach 1:
Segmenting the through connection allows achieving better impedance matching without increasing the overall through hole diameter. The distributed wall segments provide effective impedance control while maintaining a compact through connection footprint that fits within standard PCB manufacturing constraints.
Solution Approach 2:
Instead of improving impedance matching by increasing the radial dimension of the through connection, the solution uses angular distribution of segmented walls around the through hole. This transforms the problem from a radial dimension issue to an angular arrangement problem, maintaining small through hole sizes while achieving impedance matching.
Data Source
AI summary
Disclosed herein are a printed circuit board and a method of making a printed circuit board. The printed circuit board includes a top surface having a top metal layer; a bottom surface having a bottom metal layer; a first through hole extending from the top surface to the bottom surface; and a first through connection disposed inside the first through hole and coupled to the top metal layer and the bottom metal layer, the first through connection including a first wall segment and a second wall segment that is separated from the first wall segment along a through direction of the first through hole. The method includes forming a through hole in the printed circuit board; disposing a through connection in the through hole; separating the through connection into a plurality of wall segments; and disposing dielectric columns among the plurality of wall segments.