Properties of electromagnetic shielding case made of plywood laminated with conductive sheets

Electromagnetic shielding cases have been regarded as an adequate solution for electromagnetic interference problems. Most electromagnetic shielding cases are made of metal, conductive plastics and carbon materials. Wood-based electromagnetic shielding cases have gained high levels of public interests due to their availability, cost, and renewability. In this study, the case was constructed of electromagnetic shielding plywood connected by copper foil. Shielding properties of the case were evaluated using shielded room testing. It was found that shielding effectiveness of the case ranged from 30.01 to 43.89 dB (30 MHz to 1 GHz), which indicated it met the secondary shielding effectiveness requirements of general cases for electronic equipment and could be used under the high requirements of electromagnetic compatibility. The results also showed seam leakage between the sides of cases resulted in a decrease of electromagnetic shielding effectiveness. The longer the seam length, the lower the shielding performance was. In addition, it was observed that rectangular waveguide resonance had an obvious influence on the case, which led to a sharp decrease of shielding effectiveness at the frequency of 720 MHz.