| 摘要 |
In an elastic wave filter (10) in which an IDT (12) is configured in a tapered shape, an object of the present invention is to provide a technology capable of suppressing deterioration of attenuation characteristics due to refraction and the like of the elastic wave and also suppressing loss. A short grating electrode (16) is disposed in the acoustic wave direction propagation between the tapered IDT (12) and an output side tapered IDT (13). Then, an input side area adjacent to an input side tapered IDT electrode (12) of this short grating electrode and an output side area close to the output side tapered IDT electrode (13) are made patterns continuous (as if extended) from the input side tapered IDT electrode and the output side tapered IDT electrode respectively. The areas between the input side tapered IDT electrode (12), the output side tapered IDT electrode (13) and the short grating electrode (16) are set in a manner that the cycle unit » which is a repeating unit of the electrode fingers is continued without breaking. |
