Electromagnetic radiation from printed traces on a circuit board with coated plastic cover

A rigorous formulation in the spectral domain is used to investigate the radiation from printed traces on a circuit board in the frequency range from 30 MHz to 1 GHz. The coupling effect among adjacent traces and the shielding effectiveness of metallic coating on the plastic cover are analyzed. It is found that the radiation around resonant frequencies is critical in satisfying the FCC (US Federal Communications Commission) requirement, and an appropriate coating can resolve the problem.