Simple Analytical Approximate Formulation for the Shielding Effectiveness of a Metallic Panel With Apertures

The present paper is proposing a methodological approach for predicting the Shielding Effectiveness (SE) of metallic walls with various apertures, supported by software simulations. First, the SE modeling for a single aperture is addressed, whereas, at the difference with an homogeneous barrier, the transmission through a slot of given length behaves as a dipole that re-radiates some of the incident RF power. Because of this, the re-radiated field behind the barrier -hence the SE- becomes dependent of the barrier-to-target distance. Next, the SE for a single row of apertures is addressed, with an attempt for quantifying its dependency upon N identical holes and their individual separation. A further step is treating the SE for an array of NxM holes, including the effect of an off-axis shift target location. Some of the simulation results are compared with those obtained by using a few, widely-used simple formulae, trying to characterize their limitations, and proposing correction factors as the discrepancy typically increase with the barrier-to-target distance.