| 摘要 |
PURPOSE:To suppress spurious response by changing at least any one of the area of a dot electrode and that of a ring electrode between any two three- terminal filter elements out of plural ones without notching a piezoelectric unit. CONSTITUTION:Each of elements 1, 2 is constituted of forming the dot electrode 4 and the ring electrode 5 on one main surface 3a of the piezo-electric unit 3 and an earth electrode 6 on the other main surface 3b. The width T1 of the dot electrode 4 and the width T2 of the ring electrode 5 are changed between the filter elements 1, 2. Consequently, respective elements can be prevented from spurious response.
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