Pulse-Induced Vibration Modes and Natural Frequencies of Piezoelectric Ultrasonic Microsensors on Buckled Diaphragm Structures

Pulse-induced vibration modes and their natural frequencies were analytically investigated on buckled diaphragm structures that enhance the sensitivity of piezoelectric ultrasonic microsensors. The diaphragm was modeled as a simplified one-dimensional beam and the natural frequency was analytically calculated using low of the conservation of energy. The strain by lateral stretching in vibration on the buckled structure was taken into account in the potential energy as well as the strain by bending deformation, and the natal frequency was expressed as a function of the buckling deflection. The analytical results were compared with those of the experimental measurement and they were in good agreement with each other from the viewpoint of the frequency change of each vibration mode and mode degeneration by approaching frequencies.