Optimizing the protection of sensitive electronic instruments inside workrooms against EM-wave penetration

A finite-difference time-domain (FDTD) method is used to study the mechanism of EM wave penetration into a typical workroom in this paper. The room includes 3 metallic enclosures representing shielding boxes containing electronic instruments. Each enclosure has an aperture installed on its front wall allowing external electromagnetic waves to penetrate into the enclosure. The incident wave is a uniform plane wave with a HEMP waveform. Different configurations are compared for the implementation of boxes in the room concerning maximum amplitude of electric field inside the enclosures. It has been shown that by an appropriate implementation of instruments the amplitude of internal fields can be reduced up to 60 percent.