Assessing board level shielding integrity, measurement discrepancies and defect identification

Abstract

Electromagnetic shielding, especially at the board level (BLS), is one of the key criteria for ensuring modern electronic devices' EMC. Proper implementation of BLS is essential for successful EMC passing, as BLS protects board level sensitive electronic components and often regarded as the last line of defense against interfering electromagnetic fields. Methods for characterizing shielding are diverse, with the recent approach described in the IEEE P2716 standard. However, identifying defects on already implemented BLS remains challenging and depends on the various measurement techniques. This research work presents preliminary results on analyzing the SE of various BLS samples using a GTEM cell and the EMxpert Near Field Scanner for emission analysis. The acquired experimental results were further processed with statistical methods to identify errors in the different BLS implementations. The concluded analysis shows that the combined measurement technique with a GTEM cell and a VNA provides more accurate and repeatable results compared to the other approaches investigated.