| 摘要 |
The surface acoustic wave device of the invention comprises a piezoelectric substrate of lithium niobate or lithium tantalate and electrodes formed on the substrate for propagating surface acoustic waves. The substrate has a cut plane and a surface acoustic wave propagation direction which are ( phi , theta , psi ) as expressed in Eulerian angles and within ranges substantially equivalent thereto. When the substrate is made of lithium niobate, phi , theta and psi are 0 DEG -86 DEG or 95 DEG -180 DEG , 73 DEG -118 DEG and 0 DEG -44 DEG , respectively. When the substrate is made of lithium tantalate, phi , theta and psi are 0 DEG -87 DEG or 91 DEG -180 DEG , 80 DEG -120 DEG and 0 DEG -44 DEG , respectively. This enables the device to exhibit high performance.
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