The analytical, numerical and neural network evaluation versus experimental of electromagnetic shielding effectiveness of a rectangular enclosure with apertures

The development and investigation of approximate phenomenological models used to estimate the electromagnetic energy coupling through apertures into enclosures is presented in this paper. Some theoretical aspects of the electromagnetic field penetration into a rectangular enclosure through apertures are reviewed. It is shown that for a simple system topology analytical formulations based on a transmission line model give good predictions of the shielding effectiveness of a rectangular enclosure with apertures. Both the magnetic and electric shielding may be calculated as a function of frequency, enclosure dimensions, apertures dimensions and positions within the enclosure. This analytical approach is validated by comparing the shielding effectiveness predictions with full-field simulations using the finite-difference time-domain technique, software CST and experimental investigations of the shielding effectiveness in a semi anechoic chamber. Industrial needs in terms of EMC require that the experimental results of the shielding effectiveness are accurate for large frequency intervals. To meet this requirement, a neural network based model is used for the implementation of inverse models in order to estimate physical and geometrical parameters of enclosures. In this context an application is considered. It Concerns the evaluation of the shielding effectiveness (SE) parameter as a function of the frequency. During experimental measurements of the SE parameter we did not get enough resolution for intermediate frequencies.