{"id":4370,"date":"2017-03-08T12:12:13","date_gmt":"2017-03-08T11:12:13","guid":{"rendered":"https:\/\/www.electronic.se\/2017\/02\/08\/shielding-of-boxes-and-enclosures-part-2\/"},"modified":"2019-12-12T09:13:37","modified_gmt":"2019-12-12T08:13:37","slug":"shielding-of-boxes-and-enclosures-part-2","status":"publish","type":"post","link":"https:\/\/www.electronic.se\/en\/2017\/03\/08\/shielding-of-boxes-and-enclosures-part-2\/","title":{"rendered":"Shielding of Boxes and Enclosures (Part 2)"},"content":{"rendered":"

Someone may wonder why treating separately cables shielding and box shielding? Against an EM field a shield is a shield, no matter if it is a tube or a cube \u2026 In fact, there is a significant difference: in a shielded cable, the wires are closely coupled with their tubular envelope, such as it is the mutual inductance that does the cancelling effect. In a shielded box there is no such close coupling: it is the portion of the field that goes through the barrier that gives a measure of the shield effectiveness. This long \u201dBox Shielding\u201d article has been split in two parts.<\/p>\n

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Part 1 (Sept. issue of EE) addressed the basic approach for successful shielding: defining the objectives and selecting the proper material and thickness. This Part 2 describes the methods\/hardware for obtaining the desired Shielding Effectiveness by controlling the various leakages.<\/p>\n

4. Shield degradation caused by apertures<\/h3>\n

All the SE figures given above assume a plain, homogeneous barrier. Real life housings are never made like continuous metal cubicles: they have slots, seams and other apertures that inevitably leak. As for a chain, a shield is only as good as its weakest link; therefore it is important to know the shield\u2019s weak points in order to match realistic objectives.<\/p>\n