| 摘要 |
A surface acoustic wave apparatus comprises a piezoelectric substrate 17 on the bottom face of which IDT electrodes 3 and 4 and an annular ground electrode 6 which encloses the IDT electrodes 3 and 4 and is connected to the IDT electrode 3 , and a base substrate on the top face of which an annular ground conductor 7 is formed and which has an internal ground conductor layer 10 a and a bottom face ground conductor layer 11 a connected to the annular ground conductor 7 and an internal ground conductor layer 10 b and a bottom face ground conductor layer 11 b connected to the IDT electrode 4 . A first ground conductor composed of the internal ground conductor layer 10 a and the bottom face ground conductor layer 11 a is electrically separated from a second ground conductor composed of the internal ground conductor layer 10 b and the bottom face ground conductor layer 11 b. The apparatus has an excellent out-of-band attenuation characteristic.
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