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Differential Mode to Common Mode Conversion on Differential Signal Vias Due to Asymmetric GND Via Configurations

1406 F3 coverThis article investigates the impact of ground vias placed in close proximity to high speed differential signal vias and the resulting differential mode to common mode conversion. The work shows the influence of the distance between ground (GND) vias and differential signal (Diff. SIG.); the effect of the asymmetrical configuration of the GND vias; the impact of the dielectric thickness and the number of transitions between the planes.

Equivalent Transmission-Line Model for Vias Connected to Striplines in Multilayer Print Circuit Boards

Each year the IEEE Electromagnetic Compatibility Society sponsors a Best Student Paper competition as part of the IEEE International Symposium on EMC.  The contest is administered by the Educational and Student Activities Committee (ESAC) of the Society.  For the 2010 Symposium 33 student papers were submitted, the largest number in recent memory.  An ESAC panel reviewed and ranked the submissions based on technical contribution, accuracy, and clarity.  It always proves to be a challenge to select a single winner from the many fine papers covering many diverse aspects of EMC that are received.  The paper selected for 2010 use modal decomposition to derive a transmission line model for printed circuit board vias that can be implemented in circuit simulators.  The new model has a significantly faster computation time than that of a full-wave simulator while giving results that are in good agreement.  The practical benefit is an improved facility for of the design and optimization of high speed digital circuit boards for both signal integrity and EMC compliance.