並聯開路殘段加載之微帶線共振腔特性及帶通濾波器之應用

Abstract

本論文研究以開路殘段加載的微帶線共振腔，內容有兩部分。第一部分研究平行耦合帶通濾波器，每個共振腔施以不同的加載，以得到不同的高階諧振頻率，達到很寬的上截止帶的設計目的。 第二部分研究以殘段加載達到多模共振腔的設計。文中設計及分析三模與五模的共振腔，並將之應用在準橢圓函數濾波器的設計。所製作的電路，模擬結果和實際量測結果相當吻合。

Parallel-coupled line bandpass filters and quasi-elliptic function bandpass filters are synthesized based on stub-loaded resonators. The open stub behaves as a capacitor which can be trimmed to produce resonators with the same fundamental frequency, but different higher order resonant frequencies. The resonators with staggered higher order frequencies are integrated in a single filter to achieve multispurious suppression in upper stupband. The tapped open stubs can also introduce an attenuation pole and a transmission zero to design a tripple-mode resonator and quintuple-mode resonator. The I/O stage is realized by means of a parallel-coupled stage. Bandpass filter is synthesized with a transmission zero on both lower and upper sides of passband. Measured results show good agreement with simulated responses.