Embedded Lab

While designing PCBs for high frequency circuits, it is critical that the characteristic impedance is under control for signal integrity and minimal EMI. One of the biggest concerns in doing so is the signal path discontinuities, including the return path on ground plane. Minoru Ishikawa has posted some tips in this article on EDN to understand the relationship between the return path discontinuities and electromagnetic compatibilty, that will help to enhance the EM compatibility of your final design.

Continuous return path provides better EMC

It’s conventional wisdom that a solid, continuous return path provides a better result in electromagnetic compatibility (EMC). This article discusses the relationship between return path discontinuities and EMC.

A quality signal channel has a nice, uniform trace and a continuous return path from driver to receiver. Disruption to the return path introduces noise, and is typically caused by:

• Changing the reference plane(s) along the signal path

• Discontinuities within the reference plane