Identifying Interference From Multiple Noise Sources by Magnetic Near Fields Only

TLDR: In this article, the authors proposed a method to identify the interference from different noise sources separately, even when they are radiating at the same time, using the decomposition method based on reciprocity theory.

Abstract: As electronic products become more and more complicated, multiple noise sources very likely interfere with the radio frequency receiver simultaneously. This paper proposes a method to identify the interference from different noise sources separately, even when they are radiating at the same time. This method converts magnetic fields to electric fields by the finite-element method (FEM) and employs the decomposition method based on reciprocity theory. In the proposed method, Huygens's surface will be set up for each source. The tangential magnetic near fields on each Huygens's surface are used to solve tangential electric fields correspondingly by the FEM. Then, the sources are removed but their Huygens's surfaces are kept. The victim structure is excited in this case to get the tangential magnetic fields on Huygens's surfaces. A creative FEM processing procedure is applied to obtain tangential electric fields in this situation. Finally, with these two groups of fields, the interference from each noise source can be estimated separately based on reciprocity theory. This method is validated by a numerical example. It is very helpful for engineers to be able to identify the contribution of the coupling from different sources and further solve the electromagnetic interference issues efficiently.