利用有限脈衝響應濾波器建立等效偶極矩模型

Abstract

本研究之主旨，即在能夠通過近場量測的方式，針對建模不易或是無法建模之元件，等效出一組偶極矩模型，以便在設計階段即可透過互易定理估計電磁干擾的耦合量。為此，本研究透過觀察偶極矩模型中基本單位偶極矩的近場場型，設計有限脈衝響應濾波器，使得當近場量測的場經過此濾波器後，能夠分辨偶極矩的種類以及位置，同時設計一套求解流程，利用電磁全波模擬軟體中設計的結構，證明可以減少計算需求量以及提升偶極矩模型的準確度。 另外為了能夠貼近實際的應用，本研究亦考慮在實際量測中的限制，即僅有強度資訊的磁場可用。分析理論與現實的差距，改善有限脈衝響應濾波器於實際使用上的極限，並且提出一套方法克服理論所不足之處，以一測試結構於實驗與電磁全波模擬軟體中驗證，結果可於合理的時間內給出一合理的偶極矩模型。

The main objective of this thesis is to calculate dipole moment models for components that are difficult or impossible to model by near-field scanning data, so that the coupling in electromagnetic interference problems can be estimated at the design stage by the reciprocity theorem. In this thesis, the near-field pattern of the dipole moment is observed, and finite pulse response filters are designed so that the type and magnitide of dipole moment can be identified by the filter. An iteration method is proposed to reduce the computations and improve the accuracy of the dipole moment model. In the practical application, this thesis also considers the limitations in the actual measurement, where only magnitude-only magnetic field data is available. In this thesis, the difference between theory and pratical case is analyzed, the limits of the finite pulse response filter in the practical use is improved, and a method to overcome the shortcomings of the theory is proposed. A structure is designed for simulation and experiment to verify the method. The major achievement is retrieving reasonable dipole moment models from magnitude-only near-field scanning in a reasonable time.