| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a discrete-type surface acoustic wave filter capable of achieving satisfactory frequency temperature characteristics. <P>SOLUTION: A surface acoustic wave filter for solving the problem is a SAW resonator 10 which uses a crystal substrate 30 of Euler's angle (-1°≤ϕ≤1°, 117°≤θ≤142°, 42.79°≤¾ψ¾≤49.57°), and has a groove 32 which is formed by recessing a portion of a substrate that is located between an IDT 12 which excites a SAW in a stop band upper end mode and an electrode finger 18 constituting the IDT 12. The upper equation is satisfied, where λ is the wavelength of the SAW and G is the depth of the groove 32, and the depth G of the groove 32 and a line occupancy ratio η satisfies the relation of the lower equation, where η represents the line occupancy ratio of the IDT 12. <P>COPYRIGHT: (C)2012,JPO&INPIT |
