Time-Domain Investigation on Cable-Induced Transient Coupling Into Metallic Enclosures

A hybrid time-domain method is proposed for characterizing electromagnetic interference (EMI) signals coupled into some composite structures with metallic enclosures, braided shielded cable, printed circuit boards, and even lumped active devices. In order to rapidly capture the induced interior EMI, the finite-difference time-domain, modified node analysis, and multiconductor transmission lines methods are combined together and implemented successfully. Numerical investigation is carried out to demonstrate the frequency-dependent transfer impedance of the coaxial cable, the induced voltage at the place of active loaded element in the transmission line network, and the enclosure shielding effectiveness of these composite enclosures. The captured transient response information is useful for further designing electromagnetic protection of the inner circuits against the impact of voltage or current surge caused by nonintentional as well as intentional electromagnetic interference.