Correlating Shielding Effectiveness and Wave Impedance for Characterizing Low-Frequency Board Level Shields using the Stripline Method

This paper investigates the correlation between shielding effectiveness and wave impedance for the characterization of board-level shields from 10 MHz up to 10 GHz by simulation models. Full-wave simulations are performed using the Finite-Difference-Time-Domain solver. The study highlights the importance of distinguishing between electric and magnetic sources when characterizing the practical performance of board-level shields for on-board shielding applications, especially considering the short distances between the shields and on-board sources. Additionally, the good level of agreement between the measured and simulated shielding effectiveness results is shown for both the $50 \Omega$ matched microstrip and the patch source. Notably, this clarification underscores that the microstrip does not function as a magnetic source, while the patch source indeed acts as an electric source when characterizing board-level shields.