| 摘要 |
PROBLEM TO BE SOLVED: To provide a SAW filter including a structure capable of increasing an attenuation amount in the vicinity of a passband, specifically an attenuation amount on a higher frequency side than the passband, without deteriorating characteristics in the passband. ! SOLUTION: In a SAW filter 21, a plurality of IDTs 23-25 are arranged along a surface wave propagation direction on a multilayer substrate 22 comprising a multilayer structure of a piezoelectric film/a low acoustic velocity film/a high acoustic velocity film/a support substrate; at least one one-port type SAW resonator 28 is connected in series to the output side of the SAW filter; and an anti-resonance frequency fa of the SAW resonator 28 is located on a higher frequency side than a passband of the SAW filter. ! COPYRIGHT: (C)2015,JPO&INPIT |
