Parallel-Coupled Bandpass Filters Based on Lumped-Distributed Coupled-Line Sections

• Main Authors: Hsi-Ming Yang, 楊錫明
• Other Authors: Chun Hsiung Chen
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/47569831261817809514

碩士 === 國立臺灣大學 === 電信工程學研究所 === 93 === In this study, parallel-coupled bandpass filters based on lumped-distributed coupled-line sections have been proposed to possess the merits of compact size, good selectivity, and good stopband rejection. Novel parallel-coupled bandpass filters are proposed, by using additional lumped capacitors or inductors to reduce the length of coupled-line sections. In addition, by introducing the capacitive or inductive cross-coupling effect, transmission zeros can be achieved to improve the filter selectivity. The locations of transmission zeros may be simply adjusted by varying the cross-coupling capacitance or inductance. Simple equivalent-circuit models and design formulas are also established, from which the proposed parallel-coupled bandpass filters based on lumped-distributed coupled-line sections may be design and investigated. Furthermore, the approach to suppress the spurious response is also discussed so as to enhance the stopband characteristics.