縮小型共平面波導與共平面帶線之四分之一波長諧振腔濾波器與平衡/非平衡轉換濾波器

Abstract

本論文主要在研究縮小型共平面波導及共平面帶線之四分之一波長諧振腔濾波器與平衡/非平衡轉換濾波器。在第一部分，我們提出新型多折之共平面波導四分之一波長諧振腔濾波器，此種多折式結構不僅大大縮小諧振腔長度，並且提供簡易方法實現濾波器交錯耦合。比起螺旋結構與曲折結構，此種有限寬度接地之單一阻抗諧振腔具有較強的耦合係數，因此它可適合應用於無限折疊之窄頻至中等頻寬濾波器。除了設計柴比雪夫濾波器之外，我們利用修正型諧振腔之交錯耦合以實現廣義柴比雪夫濾波器。此外，基於單一阻抗諧振腔設計，可進一步提出新型共平面步階阻抗諧振腔，它具有更高的偽帶頻率。第二部分，我們提出具有共平面波導埠端之共平面帶線單一阻抗諧振腔濾波器與平衡/非平衡轉換步階阻抗諧振腔濾波器，由於共平面帶線具有天生平衡特性，所以此濾波器之共平面波導平衡埠端信號展現良好的平衡效果。此外，此平衡/非平衡轉換步階阻抗諧振腔濾波器具有簡單設計程序，比起傳統共平面帶線濾波器，僅需於平衡端計算外部耦合係數。藉著四分之一波長步階阻抗諧振腔，此平衡/非平衡轉換濾波器可以達到體積縮小化與抑制偽帶頻率至四倍頻以上。

This dissertation presents the studies and applications of compact coplanar waveguide (CPW) and coplanar stripline (CPS) quarter-wave resonator filters and balun filters. In the first part of this dissertation, the novel multifold finite-ground-width coplanar waveguide quarter-wave resonator filters are presented. The proposed filters not only significantly shorten the length of a resonator but also provide a convenient way to implement the cross coupling in a filter. The proposed multifold finite-ground-width CPW uniform-impedance resonators (UIRs) have much stronger coupling than that of spiraling and meandering layouts, hence it is suitable to implement a narrow to moderate bandwidth filter with any number of folds in a resonator. In addition to Chebyshev filter response, generalized Chebyshev response by applying the cross coupling between the nonadjacent resonators has also been implemented by modifying the layout of some resonators in the filter. Besides, the novel CPW □/4 stepped-impedance resonators (SIRs) are proposed by modifying the layout of multifold CPW resonators which can provide better upper stopband response. In the second part of this dissertation, the CPS quarter-wave UIR filters and the quarter-wave CPS SIR balun filters with CPW input/output ports are proposed. Since CPS is a balanced transmission line, the two balanced CPW signals in a CPS SIR balun filter show nearly perfect magnitude and phase balance. Furthermore, the design procedures for the CPS SIR balun filters are so easy that only the calculation of the external coupling of balanced ports is different from a conventional CPS filter. Because of the use of the □/4 SIR, the proposed balun filters are compact in size and show a spurious passband frequency greater than four times the operating frequency.