Design of Dual-Band Microstrip Bandpass Filters

• Main Authors: Chung-Rung Chen, 陳重榮
• Other Authors: Chih-Ming Tsai
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/77934427801502642003

碩士 === 國立成功大學 === 電機工程學系碩博士班 === 91 === To design a dual-band microstrip bandpass filter, one needs resonators and coupling structures with dual-band characteristics. Also, the matching problem of both bands at the input and output ports need to be solved. This thesis proposes a class of dual-band resonant structures based on the effect of stepped impedances. Then the resonators are bended and put close together to yield the needed dual-band coupling coefficients. To solve the matching problem of both bands, the thesis derives the formula of loaded Q of resonators and further proposes a modified dual-band inverter. If the ratio of second pass-band center frequency to the first one is between 1.5 and 2.5, the proposed structures and method can be used to design a second-order dual-band bandpass filter successfully.