高頻抑制之高溫超導微波濾波器設計與研究

Study of HTS Microwave Filters with High-frequency Spurious Suppressions

莊英賢(Ying-Shyan Juang)

指導教授 ： 鄭慧愷

中原大學/工學院/電子工程研究所/碩士(2009年)

https://doi.org/10.6840/cycu200900423

摘要

在本論文中，我們於一面積1.2 cm  1 cm 之鋁酸鑭(LAO)基板上以YBCO高溫超導（high-temperature superconductor，HTS）薄膜設計一高頻抑制結構之交錯耦合型濾波器，並對其微波性質作一系列之研究。此微波濾波器主要由一22四階交錯耦合型之內摺式步階阻抗共振器（stepped impedance resonator）組成，其共振器之中心頻率可分別設計為1.8、1.9、2.0及2.4 GHz。此外，我們於對稱饋入（skew-symmetrical-feed）線結構中加入一殘斷來達成高頻諧波抑制，同時增加通帶外之截止帶衰減的特性。實際上此濾波器之設計不僅達成縮小元件尺寸之目標，也在頻率響應模擬中顯示出插入損耗（insertion loss）小於0.1 dB及反射損耗（return loss）高於18 dB之優良特性。尤其是我們藉由適當地調整饋入線結構，可使濾波器於通帶中有較佳之選擇性及較小的插入損耗，且有效抑制高階諧波及截止帶達10 dB以上。

關鍵字

高溫超導微波濾波器 ； 高頻抑制

並列摘要

In this thesis, we designed a high-frequency spurious suppression structure on a filter to study the microwave properties of the microstrip cross-coupled planar filters using YBCO high-temperature superconductor (HTS) thin films on a LAO substrate with the area of 1.2 cm  1 cm. The microwave filters based on a quadruplet geometry are used to the inner-folded stepped impedance resonator (SIR) with respect to the central frequencies at 1.8, 1.9 2.0 and 2.4 GHz, respectively. Furthermore, a tap-connection technique by tapping the input microstrip lines with a stub at the skew-symmetrical-feed structure is applied to the microwave filters so as to suppress high-order harmonics and meanwhile to enhance the stop-band characteristics. The real device performances for this structure not only have a size reduction, but also display an insertion loss below 0.1 dB and return loss higher than 18 dB for the frequency responses in simulation. In particular, we demonstrated that, by properly arranging the feeding configuration, filters with better selectivity and smaller insertion loss have been realized by introducing a spurious suppression structure at feeding line, and have effectively suppressed the high-order harmonics and stop-band more than 10 dB.

並列關鍵字

Spurious Suppression ； HTS Microwave Filters

參考文獻

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