Lead-Zirconate-Titanate Acoustic Energy Harvester Equipped with Sound-Collecting Helmholtz Resonator

摘要

Acoustic energy harvesters that function in environments where sound pressure is extremely high (～150 dB), such as in engine rooms of aircraft, are expected to be capable of powering wireless health monitoring systems. This paper presents the power generation performance of a lead-zirconate-titanate (PZT) acoustic energy harvester with a vibrating PZT diaphragm. The diaphragm had a diameter of 2 mm, consisting of Al (0.1 μm)/PZT (1μm)/Pt (0.1 μm)/Ti (0.1 μm)/SiO_2 (1.5μm). The harvester generated a power of 5 x 10~(-14) W under a sound pressure level of 110 dB at the first resonance frequency of 6.28 kHz. It was found that the generated power was increased to 2.0 × 10~(-13) W using a sound-collecting Helmholtz resonator cone with a height of 60 mm. The cone provided a Helmholtz resonance at 5.8 kHz, and the generated power increased from 9.7 × 10~(-15) W to 7.3 × 10~(-13) W at this frequency. The cone was also effective in increasing the bandwidth of the energy harvester.