| 摘要 |
Surface acoustic wave device (10) includes substrate (1) including lithium niobate; comb-shaped electrode (22) being provided on an upper surface of the substrate and including a plurality of electrode fingers (22a); and protective film (4) covering comb-shaped electrode (22) and having an uneven shape on an upper surface thereof. When a pitch width of one pitch of comb-shaped electrode (22) is p, a width of one of electrode fingers (22a) is p1, a width between electrode fingers (22a) is p2, and a thickness of comb-shaped electrode (22) is h, following relations are satisfied, p1 + p2 = p, and h / (2 × p) ‰¥ 4.5%. With this configuration, an appropriate reflection characteristic is realized, and surface acoustic wave device (10) having excellent temperature coefficient of frequency and electrical characteristic can be obtained. |
