| 摘要 |
<p>An elastic wave filter device having a pass band on the low level side of a trap band, exhibiting excellent sharpness in attenuation characteristics from the pass band to the trap band, and being capable of ensuring a large attenuation in the trap band. The elastic wave filter device (1) is provided, in a series arm connecting an input terminal (3) and an output terminal (4), with a plurality of inductors (5, 6) connected in series, and a plurality of elastic wave resonators (7-10) connected between the series arm and the ground potential, wherein a plurality of filter circuits, each consisting of at least one inductor (5 or 6) and first elastic wave resonators (7, 8 or 9, 10) are constituted from the input terminal (3) toward the output terminal (4), a second elastic wave resonator (11) is inserted into the series arm, and adjoining filter circuits are connected to each other by the second elastic wave resonator (11) at at least one point of a portion where filter circuits adjoin each other.</p> |
