| 摘要 |
A surface acoustic wave device (20) includes a first surface acoustic wave filter (1) forming a ladder filter circuit, and a second surface acoustic wave filter (2) having a passband at a frequency range higher than that of the first surface acoustic wave filter (1). The first surface acoustic wave filter (1) includes a series-arm surface acoustic wave resonator (76), a parallel-arm surface acoustic wave resonator (8a,8b) and an additional surface acoustic wave resonator (15a). The series-arm surface acoustic wave resonator (76) is on a series arm of the ladder filter circuit (1) and includes an IDT electrode. The parallel-arm surface acoustic wave resonator (8a,8b) is on a parallel arm of the ladder filter circuit and includes an IDT electrode. The additional surface acoustic wave resonator (15a) includes an IDT electrode, is connected in parallel with the series-arm surface acoustic wave resonator (76), and has a resonance frequency higher than the frequency range of the passband of the second surface acoustic wave filter (2). |
