使用平行耦合微帶線設計雙通帶濾波器

Abstract

摘要 近年來，由於無線通訊的迅速發展，使得具備雙通帶響應(dual passband response)的高品質濾波器需求增加。目前已知的步階阻抗諧振腔(Stepped-Impedance Resonator , SIR)，可以藉由改變諧振腔的結構參數調整第一與第二諧振頻率。然而，使用SIR同時合成兩個通帶對電路設計者而言是一大挑戰。本論文將提出一個方法，設計具有雙通帶響應的SIR帶通濾波器，SIR的結構參數由兩頻帶的規格決定；在雙通帶濾波器中，鄰近兩個SIR的耦合長度(coupling length)與線距(gap)，則由文中提出的方法決定。

Abstract Recent advances in wireless communication have created a need of high-performance filters with a dual-passband response. It is found that both the fundamental and first higher order resonant frequencies of a planar stepped-impedance resonator (SIR) can be easily adjusted by changing its structural parameters. Simultaneous synthesizing the two passbands for an SIR filter, however, is a challenge to circuit designers. In this thesis, we propose a method for designing SIR bandpass filters with a dual-passband response. The structural parameters of an SIR are determined by specified passbands. Then, in a filter, the gap and coupling length between two adjacent SIR’s are determined by the coupling coefficients specified by the design equations.