Shielding Effectiveness and Coupling Characteristic of Metallic Enclosures with Apertures under EMP

Shielding effectiveness (SE) and coupling characteristic of metallic enclosures with apertures excited by EMP are investigated. The coupling results of different configurations and number of apertures are discussed. The coupled electric field strength is the highest in the small area adjacent to the aperture. The electric field evolvement exhibit resonant behaviour evidently and the resonant peak is present at the center inside the enclosure. For the case of the same area of a single aperture, the SE of the enclosure with rectangular aperture is lowest, and which with circle aperture is highest. The SE of the enclosure with double-layers wall is improved significantly. Besides, keeping the total area unaltered, dividing the single larger aperture into multiple smaller apertures, the SE of the enclosure will be increased.