| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface acoustic wave (SAW) device in which deterioration in insertion loss is reduced, while sustaining a wide passband, and the flatness of passband is enhanced, and to provide a communications device. SOLUTION: A plurality of IDT electrodes 2-7, having a large number of electrode fingers, are arranged on a piezoelectric substrate, in a direction orthogonal to the direction of SAWs propagating thereon. Two adjacent IDT electrodes are constituted, respectively, of first portions L2 and L3 having an electrode finger pitch different from that of the remaining portion in one part from the counterpart side end, and second remaining portions L1 and L4 having a constant electrode finger pitch in the remaining portion. The average value of the electrode finger pitch in the first portions L2 and L3 is set shorter than the electrode finger pitch in the second portions L1 and L4, the electrode finger pitch in the first portions L2 and L3 becomes shorter toward the boundary of two adjacent IDT electrodes. In the first portions L2 and L3, there are provided a plurality of electrode finger pitch minimal parts, wherein the electrode finger pitch in the boundary between the two adjacent IDT electrodes becomes shorter than that in the second portions of the two adjacent IDT electrodes. COPYRIGHT: (C)2011,JPO&INPIT
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