| 摘要 |
PURPOSE:To attain high frequency resonator by providing an inter-digital electrode finger having 3/4lambda electrode width and a reflecting electrode finger array whose electrode width is 3/4lambda and gap width is 5/4lambda (lambda is a wavelength of a surface acoustic wave with respect to a desired resonance frequency). CONSTITUTION:The interdigital electrode finger 2 whose electrode width 3/4lambda is provided on a piezoelectric substrate 1 and the reflection electrode finger array 3 whose electrode width is 3/4lambda and width is 5/4lambda is arranged to both sides. Since the reflecting electrode is arranged at every 2lambda although the electrode finger 2 has the electrode width of 3/4 lambda and the gap width, the wave of wavelength 3lambda being a fundamental wave is cancelled in the reflecting electrode and not excited, where lambda is the wavelength of the surface acoustic wave with respect to the desired resonance frequency. On the other hand, since the wave of a wavelength lambda being a ternary harmonic is resonated by the reflecting electrode, only the surface acoustic wave whose wavelength lambda is excited. Thus, the electrode width is three times in comparison with a convention a resonator, high frequency application is attained and the yield is improved.
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