The Impact of Electrical Contact Degradation of Conductive Foam on Near-field Radiation

Conductive foams are extensively used in grounding network of electronic systems to provide electromagnetic shielding or current return path. Foam degradation may lead to an increase in electromagnetic radiation and is one of the major causes of low electromagnetic compatibility characteristics. Compared with far-field electromagnetic radiation, near-field electromagnetic radiation characteristics are more complex. Accordingly, a better understanding of the influence of electrical contact degradation of conductive foam on near-field radiation is of substantial value. In the present work, the effect of conductive foam degradation on near magnetic field was studied from the perspectives of both model simulation and experimental testing. Based on the size and material of the circuit board with degraded conductive foam, a 3D electromagnetic field numerical calculation model was developed. The amplitude of the near magnetic field of the circuit board before and after foam degradation was calculated. The results obtained from the model simulation were validated using the experimental tests. The experimental results show good agreement with model predictions.