On Resonance and Shielding of Printed Traces on a Circuit Board

A rigorous formulation in the spectral domain is used to investigate the radiation from unterminated traces printed on a circuit board in the frequency range from 30 MHz to 1 GHz. Both the effect of coupling among adjacent traces on the resonant frequencies, and the shielding effectiveness of metallic coating on the plastic cover are analyzed. It is found that the radiation around resonant frequencies is critical to comply with the FCC specifications, and an appropriate coating can resolve the problem. © 1990 IEEE