Approximate Analytical Calculation of Magnetic Shielding of Double-Layer Conducting Plates with Periodic Apertures

This article focuses on the theoretical calculation method of low-frequency magnetic shielding of double-layer conducting plates with periodic apertures. The shielding effectiveness is measured when the double-layer CPPA is placed be-tween a pair of conductor rings, one ring for emissing and another ring for receiving. A surface-impedance-based theoretical model is developed to predict the shielding effectives, and the model is simplified under the quasi-static condition. The integral formula works well when the plate-to-plate distance is larger than the aperture diameter. In addition, a physical model was built in the laboratory for measurement, and the theoretical calculation results were compared with the actual measurement results. Finally, an approximate formula is obtained by simplifying the formula under some assumptions and the conclusions of some literatures.