Piezoelctric d33 mode diaphragm energy harvester for self-powered sensor application

This work presents the design, fabrication, and characterization of an energy harvester using a piezoelectric freestanding bulk diaphragm as the sensing element. The diaphragm containing the spiral electrode operates in d₃₃ mode, which is different from the commonly used d₃₁ mode diaphragm. The polarization in the diaphragm has a complex distribution that follows to the poling field induced by the double spiral electrode. The matching load impedance and the optimized working frequency were characterized.