Shielding properties of conductive plastic housings loaded with printed circuit boards

Abstract

In this paper the benefits of using conductive plastics in enclosure configurations have been evaluated taking into account the influence of internal printed circuit boards. Conductive plastic enclosures are a very attractive alternative to traditional metallic enclosures to protect electronic systems against electromagnetic interference. A wide range of conductivities can be obtained with these materials to satisfy a required design. An equivalent model for the printed circuit board has been used to evaluate the effects of radiated interference upon electronic equipment under two orientations. The possibilities and drawbacks of this equivalent model are also discussed. Two different designs with these materials have been studied to analyse the advantages derived from its use with the help of measurements and simulations. Shielding effectiveness and Q-factor have been used to compare the shielding properties of these enclosures with similarly sized metallic ones, taking into account the influence of an internal printed circuit board.