A Study on Capacitor-backed Synthesized Coplanar Waveguides with Stopband Attenuation

• Main Authors: Huang-Chin Chiu, 邱皇欽
• Other Authors: Tzyh-Ghuang Ma
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/81191450865416713115

碩士 === 國立臺灣科技大學 === 電機工程系 === 98 === A study on synthesized coplanar waveguide is performed in this thesis. We propose a novel slow-wave structure, namely, the capacitor-backed synthesized coplanar waveguide with transmission zero for developing new miniaturized hybrid couplers and dual-mode ring bandpass filters with harmonic suppression capabilities. The new synthesized line is realized by utilizing quasi-lump elements along with a LC tank. The design principles, propagation characteristics, lump equivalent circuit models, and stimulated and measured results will be discussed carefully. In the meantime, we extend the application of the previous proposed capacitor-backed synthesized coplanar waveguide to dual-mode bandpass filter design, as well. By utilizing the newly proposed capacitor-backed synthesized coplanar with transmission zero, miniaturized 90o and 180o hybrid are designed and discussed. Tabulations are provided for comparison purpose. The occupied size of the 180o hybrid is the same as reported using printed circuit board technology. Two novel miniaturized dual-mode ring band-pass filters are also proposed in this thesis. With the transmission zero introduced by either the saw-tooth feed lines or the synthesized coplanar waveguides, the two dual-mode filters successfully suppress the second harmonic of the fundamental one. When compared with the designs in literature the proposed filters not only preserve good circuit responses but show excellent size reduction capabilities. The new filters will be investigated and compared carefully in the thesis.