Reconstruction of Equivalent Emission Sources for PCBs From Near-Field Scanning Using a Differential Evolution Algorithm

An efficient method to extract equivalent radiated emission sources for printed circuit boards (PCBs) from near-field (NF) scanning data is presented. The equivalent sources are represented by elemental magnetic dipoles placed over a planar surface on the component side of a PCB. A global optimization procedure, based on the differential evolution algorithm, is used to determine the components of each dipole moment, by exploiting only the magnitude of the scanned NF data. The number and positions of the equivalent dipoles are predetermined by analyzing the scanning NF data, which is based on the NF radiation pattern of a single straight trace on a PCB. The effects of both of the spacing of the scanning points and the distance between the scanning and the reconstruction planes on the accuracy of the reconstructed results are studied. The proposed method is validated by the comparison of the reconstructed and full-wave results for PCBs with different types of traces.