平面式雙環型六埠交叉器與缺陷接地面結構式雙頻帶通濾波器設計

Design of Planar Six-Port Crossover With Two Cascoded Rings and Defected Ground Structure Dual-Band Bandpass Filter

莊偉閔(Wei-Min Chuang)

指導教授 ： 湯敬文

國立中正大學/工學院/電機工程學系/碩士(2015年)

摘要

本論文分為兩部份。

第一個部分，設計六埠的交叉器。並使用奇偶模對稱理論來分析其電路。
透過四分之一波長支線疊接兩個雙環架構，產生六埠交叉器的特性。透過推導的公式與所選定的阻抗，在ADS軟體上模擬其特性結果，以預測其操作頻寬。經由實作結果得知，本架構在|S11| ≤ -15dB的情況下有13.5%的比例頻寬，與其他論文相較，此電路結構擁有較好的操作頻寬。

第二個部份為設計DGS(缺陷接地面結構)諧振腔的雙頻帶濾波器，結合兩組DGS諧振腔達成雙頻帶的效果。此電路利用耦合係數法控制輸入/出埠的饋入點位置和調整DGS諧振腔的間距，達成同時匹配雙頻帶的頻帶響應。上述濾波器的設計，使用全波電磁模擬軟體HFSS進行模擬輔助，以及實際製作電路進行量測。經由電磁模擬與量測的結果比較，兩者具有良好的一致性。

關鍵字

耦合係數法 ； 帶通濾波器 ； 交叉器 ； 六埠網路 ； DGS(缺陷接地面結構)諧振腔

並列摘要

In the first study, A six-port crossover have been proposed in this thesis. Analytical equations of the circuit are derived by using the even-odd mode and the sixfold symmetry methods. By the approach of cascoding two rings with quarter-wavelenth branches, the six-port crossover can be implemented greatly. Moreover, based on the derived formulas, the software ADS is used to calculate the performance for selecting line impedance, investigated on the predetermined operational bandwidth. For experimental verification, the presented crossover has a bandwidth of 13.5% for 15dB return loss. Compared with the other previously reported, it has feature for wide operational bandwidth and compact size.

The second part is design the dual-band bandpass filters with DGS(Defected Ground Structure) resonators. Combining the two DGS resonators, the results of dual passbands can be obtained. In addition, the use of tapped input/output and adjust the gap between two DGS resonators can achieve the simultaneously matching among the designated passbands. This filter is simulated with full-wave electromagnetic simulator HFSS, and the prototype of the bandpass filters are fabricated and measured. Comparing with simulated results and experimental data, we can find that the measured results can match well with the EM simulation

並列關鍵字

coupling coefficient method ； dual-band bandpass filters ； crossover ； Six-port network ； DGS(Defected Ground Structure) Resonators

參考文獻

[2] G.E. Ponchak and E. Tentzeris, “Development of finite ground coplanar (FGC)waveguide 90 degree crossover junctions with low coupling” in IEEE MTT-S Int. Dig., Boston, MA, USA, pp. 1891–1894, June 2000.

[3] S. C. Wu, H. Y. Yang, N. Alexopoulos, and I. Wolff, “A rigorous dispersive characterization and microstrip cross and T junctions,” IEEE Trans. Microw Theory Tech., vol. 38, no. 12, pp. 1837–1844, Dec. 1990.

[4] T. S. Hong, “A rigorous study of microstrip crossovers and their possible improvements,” IEEE Trans. Microw. Theory Tech., vol. 42, no.9, pp. 1802–1806, Sept. 1994.

[5] A. Abbosh, “Wideband planar crossover using two-port and four-port microstrip to slotline transitions,” IEEE Microw. Wireless Compon. Lett., vol. 22, no. 9, pp. 465–467, Sep. 2012.

[6] W. Liu, Z. Zhang, Z. Feng, and M. Iskander, “A compact wideband microstrip crossover,” IEEE Microw. Wireless Compon. Lett., vol.22, no.5, pp.254-256, May 2012.