高選擇度平衡轉非平衡帶通濾波器

Highly Selective Balanced to Unbalanced Bandpass Filter

郭曜嘉(Yao-Jia Guo)

指導教授 ： 吳建華

國立中正大學/工學院/電機工程學系/碩士(2015年)

摘要

此論文為整合射頻收發機系統中，天線後端接收電路所需的平衡轉非平衡帶通濾波器。
天線後端相接平衡轉非平衡帶通濾波器，具備有使頻帶外雜訊衰減並在頻帶內通過兩個同振幅、相位差180∘的訊號。文中提出跳脫傳統將對稱四端埠電路其第三端埠開路之設計，改採用調整第三端埠反射係數(Γ3)，產生額外的零點，提升頻帶外抑制效果。電路中段架構使用三段式步階阻抗共振腔，調節對稱耦合線偶模態下諧波項出現頻率，再改變頻帶外諧波項，維持良好的頻帶外抑制。實驗結果顯示通帶範圍由2.43-2.53 GHz。頻帶外抑制表現，從1.2f0至4.5f0插入損耗可達25dB。

關鍵字

頻帶外抑制 ； 步階阻抗共振腔 ； 平衡轉非平衡帶通濾波器 ； 對稱四埠網路轉三埠巴倫器

並列摘要

This thesis focuses on the design of balun bandpass filter, used behind the antenna in. All the proposed circuits were fabricated by PCB FR4 process.
This thesis focuses on the design of balun bandpass filter, used behind the antenna in receiver. All the proposed circuits were fabricated by PCB FR4 process.
A bandpass filter integrated with a balun, called “balun bandpass filter”, decreases the out band noise and makes two signals equal in amplitude but out of phase at output. The insertion loss is related to reflection coefficient Γ3 of the port-3. In this study, another way is different from a traditional type to create a additional transmission zero by changingΓ3, is proposed to improving the out band suppression.
The middle section of this circuit adapt a three section SIR, adjusting the frequency of even mode response which is created by symmetrical coupled lines. Then the three section SIR coordinates Γ3 to change the frequency response and makes with good out band suppression performance. This work successfully implemented a passband from 2.43GHz to 2.53GHz, and a 25dB rejection upper stopband from 1.2f0 to 4.5f0.

並列關鍵字

Stopband Suppression ； Stepped Impedance resonators ； Balun Bandpass filters ； Symmetrical four ports network transfers to three ports balun

參考文獻

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[4] S.-H. Weng, H.-Y. Chang, and C.-C. Chiong, “A DC-21 GHz low imbalance active balun using darlington cell technique for high speed data communications,” IEEE Microw. Wireless Compon. Lett., vol. 19, no. 11, pp. 728–730, Nov. 2009.

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