Enhancement of Shielding Effectiveness of Double-Layer Shielding Structures With Narrow Slots Due to Parallel Wires

This study investigated the enhancement characteristics of the shielding effectiveness (SE) of a double-layer shielding structure with narrow slots when a plane wave is incident on the slot. Integral equations for aperture magnetic currents in narrow slots were derived and solved by applying Galerkin's method of moments. The numerical results demonstrate that SE depends on the layer wall spacing for a given frequency. The SE fluctuates with the spacing of the layers, and the fluctuation period is approximately 0.5 lambda at the resonant frequency. These periodic SE patterns gradually increase in magnitude with increasing layer wall spacing. To enhance the SE against electromagnetic interference at the resonant frequency, two parallel wires were used to minimize the transmission (maximize SE) through the narrow slots. The analysis results show that the SE can be enhanced by connecting the parallel wires to the slots at the resonant frequency. Experimental results are presented to validate the theory.