| 摘要 |
PROBLEM TO BE SOLVED: To improve the group delay time temperature characteristics by means of a surface wave consisting primarily of an SH wave and to miniaturize a device by forming an interdigital transducer consisting of one or more pairs of comb-shaped electrodes on a substrate of a langasite single crystal having a specific relation among Eulerian angles. SOLUTION: A piezoelectric substrate 2 uses a langasite single crystal (La3Ga5 SiO14) having Eulerian anglesϕ,θandψdefined as 0<=ϕ<=30 degrees, 0<=θ<=25 degrees andψ=-1.07ϕ+90±5 degrees respectively. Then an interdigital transducer 3 consisting of an electrode material such as Al, Au, etc., is formed on the substrate 2 with the tooth parts of a pair of comb-shaped electrodes 3a and 3b placed opposite to each other. A surface wave resonator 1 with such a constitution uses a surface wave consisting primarily of an SH wave to improve the group delay time temperature characteristics(TDC). Thus, it's possible to improve the TCD and also to omit a reflector for miniaturization of a device.
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