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1. (WO2017149878) BAND STOP FILTER AND COMPOSITE FILTER

Pub. No.:    WO/2017/149878    International Application No.:    PCT/JP2016/085989
Publication Date: Sat Sep 09 01:59:59 CEST 2017 International Filing Date: Sat Dec 03 00:59:59 CET 2016
IPC: H03H 9/64
H03H 9/145
Applicants: MURATA MANUFACTURING CO., LTD.
株式会社村田製作所
Inventors: YAMADA, Takayuki
山田 貴之
Title: BAND STOP FILTER AND COMPOSITE FILTER
Abstract:
In a band stop filter (3) which includes a plurality of parallel resonators (11 to 14), each of the plurality of parallel resonators (11 to 14) includes a piezoelectric substrate (53) and an IDT electrode (101) formed on the surface of the piezoelectric substrate (53). Each IDT electrode (101) is formed from a pair of mutually-opposing comb-tooth electrodes (110a, 110b), and each IDT electrode (101) includes a plurality of electrode fingers (111a, 111b). The pitch of the electrode fingers (111a, 111b) differs between an end portion (e) of the IDT electrode (101) in an acoustic wave propagation direction (X-direction), and a central portion (c) different from the end portion (e).