Characteristics of Reflection of Resonators Using Lamb Wave on AT-Cut Quartz

Lamb waves propagating on an AT-cut quartz substrate were studied. In this study, we propose a high-frequency resonator using a Lamb wave. A Lamb wave is excited on an extremely thin AT-cut quartz substrate which thickness is comparable to the wavelength of an elastic wave propagating on a substrate. This Lamb wave propagates at a higher phase velocity mode than surface acoustic waves. This realizes an RF resonator operable in a high frequency range in which a conventional quartz resonator hardly operates. A theoretical analysis of the reflection coefficient of a Lamb wave with a grating reflector was conducted. The analysis results and experimental results are compared and discussed in this study. A reflection coefficient which is 10 to 20 times higher than that for a Rayleigh-type surface acoustic wave is obtained.