Design of multiple-mode resonator bandpass filters

• Main Authors: Chiang, Chun-Lien, 江純蓮
• Other Authors: Wu, Tzong-Dar
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/vj46fg

碩士 === 國立臺灣海洋大學 === 電機工程學系 === 107 === In this thesis, we designed and implemented a rectangular waveguide bandpass filter with a center frequency of 22.22 GHz and a bandwidth of 547.75 MHz. The dual-mode resonant cavities were used to explore the characteristics of the transmission zero. Due to the property of high Q value, the higher-order mode was chosen to reduce the filter insertion loss. A four-cavity waveguide filter with two TE102/TE201 dual-mode cavities and two TE101 single mode cavities has been constructed and tested. The measurement results show that the passband performance is matched to the prediction of the computer simulation except that the measured bandwidth is 60MHz less than the simulated. In the fourth chapter of this thesis, we analyzed the influence of several parameters to the adjustment the position of the transmission zero for the dual-mode resonant cavity. In addition, another resonant cavity called “Singlet” structure seen from the literature has been chosen for the comparison. Singlet has only a single cavity, but has the characteristics of producing transmission zero. It has been shown that in our simulation the dual-mode resonant cavity has the better stop band performance than the Singlet although the filter designed with the Singlet often has the smaller size. Finally the combination of these two kinds of resonant cavities has also been discussed for the design of a four-order waveguide bandpass filter.