| 摘要 |
A boundary acoustic wave filter device that is able to reduce an insertion loss within a pass band is provided. A longitudinally coupled resonator boundary acoustic wave filter device 100 includes: a piezoelectric substance made of LiNbO 3 having a principal plane obtained by rotating the Y-axis through 15 degrees +-10 degrees; a dielectric substance made of silicon oxide and laminated on the piezoelectric substance; and an electrode structure arranged at a boundary between the piezoelectric substance and the dielectric substance. The electrode structure includes: a plurality of IDTs 112 to 114, 122 to 124, 132 to 134, 142 to 144, 152 to 154, and 162 to 164, arranged in a direction in which a boundary acoustic wave propagates; and reflectors 111, 115, 121, 125, 131, 135, 141, 145, 151, 155, 161 and 165, and wherein where in each of the plurality of IDTs, the overlap width of electrode fingers is W and the interval of electrode fingers is P, 20 ‰¤ W/P ‰¤ 45 is satisfied.
|
