C型槽線結構之共模濾波器設計

Absorptive Common-mode Filter Design with C-shaped Slotline Structure

洪健華(Chien-Hua Hung)

指導教授 ： 吳宗霖

國立臺灣大學/電機資訊學院/電信工程學研究所/碩士(2014年)

https://doi.org/10.6342/NTU.2014.10575

摘要

利用訊號干擾的技術，本文提出一種新穎的共模濾波器。此濾波器是由一組差模訊號線和指環狀槽孔接地結構所構成，而其等效電路能夠有效地解釋如何創造出傳輸零點。此結構是在綠能材料下實現，其大小約為 ，而對應到的物理尺寸為 。此濾波器可以對3.85秭赫茲到7.4秭赫茲的共模雜訊產生超過10 dB的抑制頻帶，並且達到63 %的比例頻寬。同時幾乎不會對差模訊號產生影響，這也意味著保持十分高品質的訊號完整度。此外，在結合上述結構下，本文提出模擬連接式電纜輻射的評估版，並且在抑制頻帶內達到壓抑電磁干擾的輻射。
其次，本文亦提出吸收式共模濾波器，在接地面上放置電阻的方式來改善輻射，其等效電路可以有效的解釋如何在單一頻率點達到最大的吸收效果。此結構實現於綠能材料下，而其大小約為0.65 0.47 ，並且對應到的物理尺寸為14 mm 10 mm。此濾波器能夠對3秭赫茲到10秭赫茲的共模雜訊產生超過10 dB的抑制，並且在3.5秭赫茲產生超過90 %的吸收功率。同樣地，保持高品質的差模訊號完整度。此外，本文也提出結合上述結構的連接式電纜輻射評估版，並在其吸收頻帶與抑制頻帶觀察到電磁干擾的輻射被壓抑。

關鍵字

共模濾波器 ； 共模輻射 ； 電磁干擾 ； 訊號完整度

並列摘要

A novel common-mode filter is proposed based on signal interference technique. It is composed of differential signal lines and the ring slot on the ground plane. Its equivalent circuit model is developed to explain how to create transmission zeroes. The proposed structure is realized on PCB substrate, and its electrical size is about corresponding to a real size of .The filter constructs the 10 dB common- mode stopband from 3.85 GHz to 7.4 GHz with a 63 % fractional bandwidth. In the meantime, very little influence is seen for differential signal, which means the high-quality signal integrity is maintained. Moreover, the cable-attached evaluation board with the proposed structure is demonstrated, and the suppression of electromagnetic interference (EMI) emission is achieved in the stopband.
Next, the absorptive common-mode filter is presented with resistors on the ground plane to improve the radiation. Its equivalent circuit model is established to explain how to reach a maximum absorption at a frequency. The proposed structure is also realized on PCB substrate, and its electrical size is about 0.65 0.47 corresponding to a real size of 14 mm 10 mm. The filter shows over 10 dB reduction from 3 GHz to 10 GHz in common mode with a 108 % fractional bandwidth, and over 90 % absorption power at 3.5 GHz. Also, the high-quality differential signal integrity is kept. In addition, the cable-attached evaluation board with the proposed structure is represented. It is observed that the EMI emission is suppressed in the stopband and absorption band.

並列關鍵字

Common-mode filter ； common-mode radiation ； electromagnetic interference ； signal integrity

參考文獻

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