Novel Formulations of Multireflections and Their Applications to High-Speed Channel Design

Abstract

Reflection theory has been long established for over decades targeted at microwave and radio frequency (RF) applications. With ultra-high-bandwidth applications emerging, such as 112 Gb/s and higher speed Ethernet protocols, discontinuities in high-speed channels negatively impact signal quality, where reflections become one of the most critical concerns in high-speed designs. In this article, for the first time, we analyzed the traditional reflection theory and proposed and verified a new formulation, which exhibits the reflection-related parameters explicitly, indicating where design optimization can be made for high-bandwidth applications using the backtracked propagation method. Our closed-form formulation is applied to high-speed channel examples, where effective mitigation of negative impact from reflections on signal integrity can be identified to be used as a prelayout channel design guide. Our proposed formulation of the reflection theory provides more accurate prediction of high-speed channel behavior to minimize the negative signal integrity impact from reflections.