| 摘要 |
PROBLEM TO BE SOLVED: To provide a piezoelectric filter which obtains band characteristics wider than those of a conventional MCF (monolithic crystal filter) and has higher practicality. SOLUTION: This piezoelectric filter is constituted by forming input and output electrodes 21, 22, 23, and 24 in parallel on the top surface of a piezoelectric plate and a common electrode 25 on the reverse surface of the piezoelectric plate, corresponding to the formation area of the input and output electrodes, and also arranging the input electrodes and output electrodes adjacently in turn, and excites thickness vibrations of (1, 1, 1) mode and (1, 1, 4) mode.
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