| Summary: | 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.
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