| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that it is difficult to use aλ/4 coupling microstrip line for a band-pass filter, which includes a jump coupling sine the positive and negative phases of transmission characteristics cannot be controlled accurately although theλ/4 microstrip line is a circuit element, with which a distributed constant filter can be easily constituted. SOLUTION: This distributed constant filter is characterized by microstrip line resonators O1 and O1 being formed by cascadingλ/4 coupling microstrip lines M1 to M3, corresponding to the center frequency of a passing band in order so that respective ports of the diagonal are connection ports, and respective ports of the other diagonal are made open and connecting connection ports among the adjacentλ/4 coupling microstrip lines M1 to M3 and the resonator length of at least one of the resonator isλ, while the resonator length of the remaining resonator isλ/2. Furthermore, a jump coupling circuit is connected between ports positioned across 2 or moreλ/4 coupling microstrip lines.
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