Mode conversion effects in multi-Gbps telecommunications blade system

Prediction of radiation from multilayer circuit boards is an important problem which is of interest to the design of digital system such as servers. In particular, signal mode conversion as the result of undesired imbalances in the board interconnects plays a significant role in the generation of noise emission. In this paper, we investigate methods for modeling common/differential mode conversion from relatively complex interconnection structures in a multi-Gbps system using a systematic approach. The strong correlation of good signal integrity practices to electromagnetic emission is discussed with emphasis on key structure contributors. The electrical modeling of key contributors (such as vias, connectors, traces, manufacturing techniques, etc.) to undesired mode conversion effects is also presented in a telecommunication blade environment.