| 摘要 |
PROBLEM TO BE SOLVED: To provide an electromechanical element capable of materializing a wide band filter with simple element structure. SOLUTION: The electromechanical element is provided with a vibratably formed piezoelectric film 21 and three electrodes (a counter electrode 22, an input electrode 23 and an output electrode 24). The input electrode 23 and the output electrode 24 are provided on the upper surface of the piezoelectric film 21 independently of each other, while the counter electrode 22 is provided on the lower surface of the piezoelectric film 21. The piezoelectric film 21 resonantly vibrates in a resonance mode having a resonance frequency and an anti-resonance frequency, however since parasitic capacitance occurring between the input electrode 23 and the output electrode 24 is serially linked to the resonance circuit linked from the input electrode 23 to the output electrode 24 via the piezoelectric film 21, the anti-resonance frequency is sufficiently away from the resonance frequency. Thus, for example, only by connecting in parallel the first electromechanical elements 1 which slightly differ in the resonance frequency from one another, the wide band filter is provided. COPYRIGHT: (C)2009,JPO&INPIT
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