Electromagnetic Shielding of Closed, Finite-Length Cylindrical Enclosures with or Without Apertures

Cylindrical shields are worthy of a specific investigation because of their diffusion in practical applications and of the analytical and numerical peculiarities. Main applications are related to cables, electromedical machines, drones, and others. The general case of finite-length, penetrable shields with and without apertures is addressed. The results obtained by means of a frequency-domain integral equation model (solved by means of a Method of Moments procedure) are used to infer general considerations in the absence of apertures and to validate the predictions ensuing from a numerical commercial code. The semi-analytical formulation is also useful for a rapid tuning of shield design. Approximate expressions available in the literature are also used for comparison and validation. In this way, the external field sufficient to impair the functionality of electronic devices protected by complex three-dimensional cylindrical enclosures may be easily estimated under the assumption of linearity of the shielding materials.