Analytical Correlation Between Time and Frequency Domain Shielding Effectiveness of Metallic Enclosures With Apertures

Time domain shielding effectiveness (SE) of metallic enclosures with apertures against electromagnetic pulse excitation has been analytically estimated and correlated to the frequency domain characteristics. The method is based on the analysis of the transient process at the aperture and an equivalent magnetic current source, to derive the initial peak amplitude appearing at the very beginning of the coupled field waveforms. The equivalent circuit model is utilized to analytically describe the frequency domain SE data. Then, a simple correlation formula has been derived, which relates the peak value reduction of the E-field and H-field to the specified spectral data minus a specially defined factor. Especially, the correlation for the E-field is shown to link the spectral SE data near the fundamental resonant frequency of TE101 mode with the peak amplitudes in time domain. A series of numerical and experimental cases have been checked to confirm the applicability of the analytical formulas. Comparisons between the data and the analysis exhibit reasonable agreements.