https://scholars.lib.ntu.edu.tw/handle/123456789/122727
Title: | 平衡式帶通濾波器及其應用 Balanced Bandpass Filters and Their Applications |
Authors: | 吳忠樺 Wu, Chung-Hwa |
Keywords: | 帶通濾波器;平衡式濾波器;巴倫濾波器;bandpass filter;balanced filter;balun filter | Issue Date: | 2009 | Abstract: | 本論文著重於平衡式帶通濾波器的研製與其應用。首先提出新型對稱四埠平衡式帶通濾波器,以達成所需要的差模帶通頻率響應同時能夠有效抑制共模雜訊。具體而言,適當的設計對稱共振器及善用共模/差模訊號饋入時對稱平面上的虛開路/虛短路條件,可以得到所需要的差模帶通及共模抑制頻率響應。為了驗證此設計概念,特採用三種目前最常被使用的濾波器架構︰集總元件、耦合線、耦合共振器,來研製各種四埠平衡式帶通濾波器。著,藉由適當引入四埠對稱網路至三埠平衡-不平衡巴倫(Balun)轉換器的轉換條件,可將先前已被研製的四埠對稱平衡式帶通濾波器轉換成新型集總元件式及耦合共振器式三埠巴倫帶通濾波器。由於所提出的三埠巴倫帶通濾波器具有可以抑制共模雜訊的特色,因此可最佳化其帶通頻率內的訊號平衡特性。後,受惠於已被良好設計的三埠巴倫帶通濾波器,而提出三個具有顯著特性 改進的應用。首先,應用低溫共燒陶瓷製程來實做一個微小化的帶通180度分合整合器。接著,提出一個整合所有被動元件至單一電路的巴倫雙工器以縮小電路尺寸及增加系統效能。最後,利用所提出的寬頻三埠巴倫帶通濾波器來做為饋入器,可實現一個寬頻quasi-Yagi天線。此寬頻quasi-Yagi天線具有寬頻穩定的同極化輻射場型、寬頻且極低的交叉極化輻射場型、及設計良好的反射損耗頻率響應。 This dissertation mainly focuses on the developments of balanced bandpass filters and their applications. In the beginning, novel symmetric four-port balanced bandpass filters are proposed to exhibit the desired differential-mode bandpass response and also suppress the common-mode signal. Specifically, by properly designing the symmetric resonators and making good use of virtual-open/-short boundaries at the plane of symmetry, it is possible to give the desired differential-/common-mode frequency responses. To demonstrate the design concept, three most widely used filter structures, lumped-element structure, coupled-line structure, and coupled-resonator structure are utilized in developing the four-port balanced bandpass filters.ext, based on the transformation conditions for converting a symmetric four-port network into a three-port balun, novel three-port balun lumped filters and balun coupled-resonator filters are implemented from the developed symmetric four-port balanced filters. Owing to the possibility of minimizing the common-mode noise, the resultant in-band amplitude-/phase-balance performances can further be optimized.inally, benefited by the well-designed balun bandpass filters, three applications with significant improvements are presented. First, a compact LTCC (low-temperature co-fired ceramic) bandpass 180? hybrid is implemented to integrate bandpass filter and 180? hybrid. Second, a balun diplexer that combines necessary passive components into a single device is presented to reduce circuit size and improve system performance. At last, a wideband quasi-Yagi antenna fed by the proposed wideband balun bandpass filter is realized to maintain stable co-polarized radiation patterns, low cross-polarized radiation levels, and a well-defined return-loss response throughout the wide passband. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/188258 |
Appears in Collections: | 電信工程學研究所 |
File | Description | Size | Format | |
---|---|---|---|---|
ntu-98-F93942060-1.pdf | 23.32 kB | Adobe PDF | View/Open |
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.