Comprehensive Evaluation of Shielding Effect of Electronic Enclosures Based on EM Norms

With the continuous deterioration of the modern electromagnetic environment, the electromagnetic sensitivity of electronic equipment is continuously improved. Metal enclosure is a common shielding method to protect electronic equipment from external electromagnetic field coupling. The suppression of electronic equipment enclosure under the strong Electromagnetic Pulse (EMP) is mostly evaluated using the traditional time-domain shielding effect. With this method, it is only considered the attenuation of the peak value of the coupled waveform in the cavity, the differences in the oscillation effect of the coupled waveform are ignored. It fails to comprehensively reflect the coupling and shielding characteristics of the cavity for different pulse waveforms. In this paper, it is proposed a comprehensive assessment method of shielding effect of electronic enclosure based on EM (Electromagnetic) norms in response to the lack of a single evaluation index of shielding effect in the time domain. A typical enclosure electromagnetic simulation model is constructed to analyze the coupling characteristics of metal cavities under different types of strong EMP, multiple EM norms of the coupled waveforms are extracted, and the differences coupled to the enclosure are compared including pulse peak, pulse energy, spectral distribution, which verifies the reasonableness and applicability of the EM norms shielding effect assessment method proposed in this paper. It is improved the theory of cavity shielding effect assessment under strong EMP, and which can provide guidance for the design of electromagnetic shielding protection of electronic equipment.