| 摘要 |
<p>Provided is a ladder-type filter which is constituted of series-arm resonators and parallel-arm resonators upon one piezoelectric substrate, and which is capable of achieving a greater increase in miniaturization. In the disclosed ladder-type filter (1), upon a piezoelectric substrate (2), series-arm resonators (S1 to S3) and parallel-arm resonators (P1 and P2) comprising acoustic wave resonators are configured, wherein at least one of the parallel-arm resonators (P1 or P2) among the series-arm resonators (S1 to S3) and the parallel-arm resonators (P1 and P2) possesses first and second resonators (P1a, P2a, P1b, and P2b) which are electrically connected in parallel, and the first resonators (P1a and P2a) and the second resonators (P1b and P2b) are juxtaposed in a direction perpendicular to the acoustic wave propagation direction at one of the exterior sides of the acoustic wave propagation directions of the series-arm resonators (S1 to S3) among the remaining resonators.</p> |
