Conference Agenda

This paper investigates how low-pass filter placement influences the shielding performance of a board-level shield when input/output traces cross its boundary. The analysis examines how these traces degrade shielding effectiveness and explores how low-pass filters suppress unwanted electromagnetic disturbances to improve again shielding performance. Additionally, the study evaluates the impact of parasitic effects from lumped elements within the filter's stopband, highlighting their role in the degradation of shielding effectiveness at higher frequencies. Finite-difference time-domain simulations were performed for five configurations to assess the influence of filter placement, proximity to the board-level shield, routing, and parasitic effects. The SAE ARP 6248 stripline method, adapted for board-level shield characterization, was used to evaluate shielding effectiveness from 1 to 40 GHz. The results indicate that placing the low-pass filter as near as possible to the board-level shield improves shielding effectiveness for both internal and crossing traces. In addition, the findings also confirm that parasitic effects in the filter’s stopband can compromise the enhancement of shielding effectiveness at high frequencies.

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.

Shielding effectiveness (SE) is a key parameter in evaluating the ability of enclosures to mitigate electromagnetic interference (EMI) in electronic systems. While existing standards define multiple SE characterization techniques, differences in practical setups and target frequency ranges often lead to complexity and measurement inconsistencies. This paper proposes a hybrid SE measurement setup for small enclosures in a reverberation chamber (RC), covering the 200 MHz to 10 GHz range with minimal modifications. A key feature of this setup is its ability to evaluate the SE of small enclosures even below the chamber’s lowest usable frequency (LUF), extending the applicability of RC-based measurements. The effectiveness of this approach is validated experimentally by comparing the absorbing clamp method with conventional techniques in the 1–3 GHz range. To our knowledge, this is the first study to integrate both conductive and radiative measurement approaches for SE characterization of small enclosures while also verifying their consistency. The proposed setup enhances the practicality and accuracy of SE characterization, making it more accessible for general EMC laboratories and industry applications.

In this work, we investigate the characteristic impedance measurements of installations as different cable types above a ground plane for differential and common mode modes. There are multiple ways of measuring the characteristic impedance, yet using open and short terminations to calculate the characteristic impedance is an extensively used method. However, the applicability of this method for different modes in a broad frequency range, the effect of the ground plane and vertical reference plane (VRP), together with the repeatability of the measurements need to be further clarified. Thus, we use thin wire and twisted pairs to address these points and propose a new perspective on characteristic impedance measurements.