L型平行耦合結構帶拒濾波器

Abstract

為了窄頻帶拒濾波器(BSF)的合成，本論文提出一個單級L型BSF之等效電路。此單級電路可為一個傳統的耦合微帶線或是一個三線的架構。根據本文所提出之等效電路，可進行具有極平坦響應或柴比雪夫響應的BSF之合成。在相同PCB板製程技術的限制下，三線結構可實現的頻寬約為傳統平行耦合微帶線的兩倍。最後，本文利用實作電路並加以量測來驗證合成與設計。

Equivalent circuit of an L-shape stage is derived for narrow bandstop filter (BSF) synthesis. The stage can be either a traditional coupled-line or a three-line structure. BSFs consisting of a cascade of these stages are synthesized based on the derived equivalent circuit. Under the same resolution limit of PCB fabrication, the three-line structure is capable of providing twice the bandwidth that a traditional coupled-line configuration can achieve. Compared with simulations, measured results are used to demonstrate the circuit synthesis and design.