| 摘要 |
A bandpass filter includes three resonators of which adjacent two are electromagnetically coupled to each other, and two coupling paths connected in parallel for forming capacitive coupling between non-adjacent two of the resonators. Each of the two coupling paths includes at least one capacitor and an inductor connected in series. The two coupling paths function to form an attenuation pole at a frequency lower than the passband frequencies in the pass attenuation characteristics of the bandpass filter.
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