Enhanced Prediction and Measurement of the Shielding Effectiveness of Reverberant Equipment Enclosures

This paper investigates the shielding effectiveness (SE) of reverberant enclosures containing electronic systems susceptible to electromagnetic interference (EMI). The approach is based on the Power Balance technique that requires values for transmission cross sections (TCS) of enclosure apertures and absorption cross sections (ACS) of enclosure internal walls and enclosure contents. Previous work has demonstrated this technique in principle for enclosures with low SE and a single simple aperture. The new approach extends the applicability of SE measurements to enclosures with various aperture shapes and sizes. Values of TCS and ACS are extracted in each case. Experimental results, conducted in a mechanically stirred reverberation chamber, show improved SE predictions, reaching up to 50 dB for enclosures with multiple complex apertures. The technique demonstrates enhanced accuracy and flexibility, crucial for designing robustly shielded electronic equipment.