Vibration spectrum of piezoelectric ceramic resonator with different diameter-to-thickness ratio

The vibration spectrum of the disk type PZT ceramics resonator with different diameter-to-thickness ratio was measured in the frequency range from 100 kHz to 1MHz. The resonant frequency ratio of fundamental mode to that of overtone mode was increased with the increasing of diameter-to-thickness ratio. With the same diameter, the resonant frequency ratio of fundamental mode to that of overtone mode was decreased with the increasing of thickness. With the same thickness, the resonant frequency ratio of fundamental mode to that of overtone mode was decreased with the decreasing of diameter. When the diameter-to-thickness ratio was less than 15, some other vibration modes were existed in the frequency range higher than 600kHz, but when the diameter-to-thickness ratio was higher than 15, the vibration mode of the disk type resonator still was pure radial mode in the entire frequency range from 100kHz to 1MHz.