A batch-fabricated electromagnetic energy harvester based on flex-rigid structures

In this paper, an electromagnetic energy harvester device is designed and fabricated, based on a rigid-flex structure. The device has a FR4 proof mass carrying a bi-layer copper planar coil, suspended by four soft polyimide springs over a disc permanent magnet. The device is batch-fabricated with a standard production process of rigid-flex Printed Circuit Board (PCB). The assembled energy harvester is excited by sinusoidal accelerations and characterized dynamically. At an acceleration of 2 g peak-to-peak amplitude (±1 g, ±9.8 m/s²), a maximum output peak-to-peak voltage of 9.85 mV and an output power of 1.24 μW are measured, at the device's resonance frequency of 155 Hz. With an elevated acceleration of 10 g (±5 g), a maximum output peak-to-peak voltage of 22.58 mV and an output power of 7.21 μW are achieved.