Optimized via Positions for Guard Traces Over a Slotted Ground to Reduce Crosstalk and Radiated Emission

Abstract

A guard trace with regularly-spaced multiple vias prevents crosstalk more effectively than a floating guard trace or end-terminated guard trace with vias or resistors. This paper proposes modified guard traces using irregularly-spaced vias to solve the design constraint problems and to ensure a good return path for the slotted ground plane. Measurements show that crosstalk and radiated emission can be reduced effectively. Modified guard traces are also shown to be effective in reducing the total number of vias.