A Multi-Stage Model for the Electromagnetic Shielding Effectiveness Prediction of an Infinite Conductor Plane With Periodic Apertures

This paper focuses on the shielding effectiveness (SE) prediction of the periodic aperture array on an infinite conductor plane against a plane electromagnetic wave with its wavelength much larger than the size of a unit cell of the array. Especially, the existing analytical expressions of SE are combined to cover the entire range of the aperture rate, which is defined as the ratio of the side length of the aperture to that of the unit cell. The combination is carried out by bridging the small aperture model and the wire mesh model. Then, a multi-stage model based on the piecewise function of the aperture rate is presented to calculate the SE for any aperture rate. The model is also extended to consider different wave polarization and incident angles. The results of the model are in good agreement with those from the full-wave simulation. The applicability of the model to a different thickness and aperture shape is discussed. In addition, the upper-limit frequency at which the model is no longer applicable is also analyzed.