Modeling Radiated Emissions Through Shielding Boxes Based on the Tangential Electrical Field Samplings Over Openings

The radiation from radiators such as PCBs inside an enclosed shielding box with ventilation slots is an important issue for electromagnetic compatibility or interference characterizations. In this paper, a two-step process is proposed based on the equivalence principle and the electric field integral equation method to complete the radiation prediction. The tangential electric fields over the slots on shielding boxes are first sampled to be the equivalent magnetic currents radiated from internal PCBs. In the second step, to avoid the computation of complex nonanalytical dyadic Green´s functions when the field radiation is computed directly from the equivalent source, the surface current induced by the equivalent magnetic current is calculated by the method of moments. As a result, the total radiated emission is the superposition of both equivalent magnetic current source and induced current. To prove the validity and accuracy of the proposed approach, near-field and far-field radiations from PCBs in enclosed environments are benchmarked and compared with simulated references.