Fabrication and Evaluation of Diaphragm Vibration Energy Harvester with 2D Mechanical Metamaterial Structure

In this paper, we propose a low-frequency diaphragm vibration energy harvester with a 2D mechanical metamaterial structure in the elastic layer. In general, diaphragm-type devices have a higher resonance frequency than cantilever-type devices. However, the metamaterial structure of the elastic layer is used to reduce the bending rigidity of the diaphragm-type devices to achieve a low resonance frequency approaching that of environmental vibrations. After investigating the device shape by FEM analysis, a diaphragm-type device was fabricated by combining the organic sacrificial layer etching method with a multilayer deposition method of piezoelectric polymer film, which can be deposited on a relatively large area with high yield, and its vibration and power generation characteristics were evaluated.