Abstract
Effects of humidity on the oscillation frequency of a resonating system utilizing a quartz piezoelectric surface acoustic wave (SAW) delay line with a deposited aluminum oxide (AlOx) thin film have been studied. With exposure to humid air, the frequency of the SAW resonator decreased instantaneously and the change in the frequency was found to be larger than that of the bulk wave resonator. The result obtained shows that the present AlOz/SAW resonator has a good possibility to be applied to a highly sensitive humidity detector.
