等效偶極矩模型擷取與射頻雜訊干擾估計方法

Extraction of Equivalent Dipole-moment Model and Estimation for Radio Frequency Interference

謝欣展(Hsin-Chan Hsieh)

指導教授 ： 吳瑞北

國立臺灣大學/電機資訊學院/電信工程學研究所/碩士(2020年)

https://doi.org/10.6342/NTU202004252

摘要

針對電路板上數位電子電路對天線所造成的電磁干擾與天線接收感度惡化的問題，本論文中首先由數位IC所輻射的近場輻射場進行掃描，利用偶極與電磁場之映射關係式，擷取雜訊源之等效偶極矩模型，並且使用正規化演算法，將等效模型加以優化，本文提出以低於近場掃描1/2高度的最低誤差定義最佳λ值，提供最佳化的簡要準則，並且假設最佳λ值不因掃描高度改變。接著利用互易定理與分解方法，估算雜訊源對天線端埠的耦合電壓，並以分布熱圖展示雜訊源與天線在不同擺置狀況的耦合電壓值。使用互易定理分析耦合雜訊，整體運算只需要正、反問題兩次模擬，在短時間內即計算不同位置元件造成的耦合電壓，與全波模擬結果誤差在2 dB以內，並大幅減少模擬計算的時間，提供前期布局能更有效率的設計方向。

關鍵字

接收感度惡化 ； 電磁干擾 ； 等效偶極矩模型 ； 射頻干擾 ； 互易定理

並列摘要

This thesis focuses on the problem of Electromagnetic Interference (EMI) and Degradation of Sensitivity (De-sense) problems caused by the radiation of digital circuits to the antennas and vice versa. An array of equivalent dipole-moment models is extracted by the near-field scanning data of an integrated circuit. With the optimization of the regularization technique, the equivalent model of the noise can reflect the information of voltage and currents on the IC as the equivalent electric and magnetic dipole moments. In order to estimate the coupled voltage from the dipole moments to the antenna, the decomposition method based on reciprocity theorem is applied, and the optimal placement of the IC and the antenna is discussed to mitigate the coupling noise.

並列關鍵字

desense ； electromagnetic interference (EMI) ； equivalent dipole-moment models ； radio-frequency interference (RFI) ； reciprocity theorem

參考文獻

[1] Q. Huang, Y. Zhong, C. Hwang, J. Fan, J. Rajagopalan, D. Pai, C. Chen, and A. Gaikwad, “Desense prediction and mitigation from DDR noise source,” in Proc. IEEE Symp. EMC SIPI, Long Beach, CA, USA, 30 July- 3 Aug., 2018.

[2] Q. Huang and J. Fan, “Machine learning based source reconstruction for RF desense,” IEEE Trans. Electromagn. Compat., vol. 60, no. 6, pp. 1640-1647, Dec. 2018.

[3] H. Weng, D. G. Beetner, and R. E. DuBroff, “Prediction of radiated emissions using near-field measurements,” IEEE Trans. Electromagn. Compat., vol. 53, no. 4, pp. 891–899, Nov. 2011.

[4] J. Shi, M. Cracraft, J. Zhang, R. DuBroff, K. Slattery, and M. Yamaguchi, “Using near-field scanning to predict radiated fields,” in Proc. IEEE Symp. Electromagn. Compat., Santa Clara, CA, pp. 14–18, 2004.

[5] M. Hernando, A. Fernandez, M. Arias, M. Rodriguez, Y. Alvarez, and F. Las-Heras, “EMI radiated noise measurement system using the source reconstruction technique,” IEEE Trans. Ind. Electron., vol. 55, no. 9, pp. 3258–3265, Sept. 2008.