Alternatives to gaskets in shielding an enclosure

It is well known that a properly placed conductive gasket can complete an enclosure to yield good shielding. But often there are reasons, e.g. control of mechanical dimensions that this cannot be achieved. For these cases, one may want to avoid using a gasket that requires contacts. This paper analyzes alternatives to continuously contacting gaskets such as overlap structures, overlapping structures with different lossy and nonlossy materials, and overlaps with grounding points. It compares structures by sufficient shielding for a typical class B product, high frequency (1-3 GHz) and low frequency (below 1 GHz) performance.