A study of EMI from patterned ground structures

It is shown that a patterned ground structure (PGS) in a printed circuit board results in a significant increase in far-field radiation, compared to the same board without the PGS. Full-3D simulations, near-field scans, and far-field measurements are used to study and quantify the increased electromagnetic interference (EMI) due to the PGS. It is concluded that the increased EMI from a board using PGS devices for common-mode filter applications is an important consideration when the board is unshielded.