A high-efficient broadband energy harvester based on non-contact coupling technique for ambient vibrations

In this paper, a high-efficient piezoelectric energy harvester based on non-contact coupling technique is proposed and characterized, which allows it, for the first time, to take advantage of multi-cantilevers and frequency up-conversion technique to enhance the power generation efficiency for ambient excitation. The unique energy harvester can effectively scavenge environmental vibration energy with a wide bandwidth. Aiming for high space efficiency and less installation constrains, folded cantilevers are designed for this energy harvester. With a load resistance of 50 kΩ, a maximum output power of 18.45 μW is achieved with the fabricated energy harvester, which is a suitable power supply for the sensor nodes in WSN applications.