Shielding effectiveness of screened rooms with line feed-throughs - a semi-analytical approach

Line feed-throughs are an important construction element used in securing the screening effect of shielded rooms, facilities and devices. Without taking special precautions at the feed-through point, the shielding effectiveness can be significantly reduced, especially if cavity resonances occur. Therefore, it is important to analyze how line feed-throughs and line lengths quantitatively affect the shielding effectiveness of such rooms. This can be addressed using the semi-analytical formulation developed in this paper, consisting of a combination of numerical 3D-field simulation (FIT) and analytical formulation. Using this method, practical protective measures have been derived and confirmed by performing measurements on a practical example. Our main focus is on the susceptibility of electronic systems in metallic rooms of a ship in an Intentional Electromagnetic Interference (IEMI) environment.