As electronic products become increasingly more complicated, multiple noise sources are likely to simultaneously interfere with the radio frequency (RF) receiver. It will be very helpful if the dominant noise source can be identified when solving the RF interference issue in a complex system. This article proposes a method to separately calculate the contributions from multiple noise sources at their overlapped frequencies so that the worse noise source could be identified even when multiple sources radiate simultaneously. The proposed method creatively employs the decomposition method based on the reciprocity theory to calculate the interference contribution from different sources. Furthermore, in the interest of reducing the near-field scanning time and complexity, the magnetic field only scanning method is developed by using the finite-element method (FEM). In the proposed method, Huygens's surface is established for each source. The tangential magnetic near fields on each Huygens's surface were then applied to solve the corresponding tangential electric fields by the FEM. Subsequently, the sources are removed while the corresponding Huygens's surfaces are maintained. The victim structure is excited under these conditions to obtain the tangential magnetic fields on Huygens's surfaces, and a novel FEM procedure is applied to obtain the tangential electric fields. Finally, based on the electric and magnetic fields, the interference from each noise source can be separately estimated based on the reciprocity theory. This method is validated by a numerical example and measurement. This approach can assist engineers in identifying the contribution of coupling from different sources and in efficiently resolving electromagnetic interference issues.

中文翻译：

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仅使用电磁近场识别来自多个噪声源的干扰

随着电子产品变得越来越复杂，多个噪声源可能会同时干扰射频（RF）接收器。解决复杂系统中的RF干扰问题时，如果能够确定主要噪声源，将非常有帮助。本文提出了一种方法，可以单独计算来自多个噪声源在其重叠频率处的影响，从而即使多个源同时辐射，也可以识别出较差的噪声源。所提出的方法创造性地采用了基于互易理论的分解方法来计算不同来源的干扰贡献。此外，为了减少近场扫描时间和复杂度，通过使用有限元方法（FEM）开发了仅磁场扫描方法。在提出的方法中，为每个源建立了惠更斯的表面。然后，通过有限元法，在每个惠更斯表面上施加切向磁场近场，以解决相应的切向电场。随后，在保持相应的惠更斯表面的同时移除光源。在这些条件下激发受害结构，以获得惠更斯表面上的切向磁场，并采用一种新颖的有限元方法获得切向电场。最后，根据电场和磁场，可以根据互易性原理分别估算来自每个噪声源的干扰。数值算例和测量结果验证了该方法的有效性。