Articles
Understanding Grounding Concepts In EM Simulators
January 5, 2010
•White Paper: Understanding Grounding Concepts In EM Simulators
By Dr. John M. Dunn, AWR
INTRODUCTION
The misunderstanding of how ground is implemented in circuit simulation is one of the most common misuses of EM simulators and their results. This white paper discusses the definition of ground in electromagnetic (EM) simulators and how to correctly choose among various grounding options, a topic of special importance to designers using the results in a circuit simulator. Many modern simulators now support the notion of local grounding, where different ports can use different ground definitions. New features in AWR's AXIEM™ 2009 3D planar EM simulator offer extensive sources/ports and de-embedding options, including internal edge, finite difference/gap and extraction ports, and per-port, coupled line and mutual group de-embedding.
Before it can be understood how ground is used in EM simulators, it is first necessary to understand how it works in circuit simulation. The major portion of the discussion involves examining where ground is defined in EM simulators and how this is a function of the solver and port types. The paper demonstrates how this flexibility in selecting ground can help the engineer characterize board, package, and interconnect performance. Several specific examples at the board, package, and chip level are discussed. The paper concludes with circuit tricks that can be used to aid in ground studies.
Click Here To Download:•White Paper: Understanding Grounding Concepts In EM Simulators
