Abstract
In this study, excellent electromagnetic interference （EMI） shielding effectiveness is obtained by multi-walled carbon nanotube（MWNT）-polystyrene （PS） composites. A better EMI shielding effectiveness by controlling different proportion of MWNT in PS matrix is detected. Furthermore, a high EMI shielding efficiency is presented with mixing only low percentage MWNT in PS. Shielding phenomenon is explained based on MWNT-PS composites permittivity and impedance. We discuss and analyze the result in the last section.