NEW COMB GEOMETRY OF CAPACITIVE VIBRATION ENERGY HARVESTERS MINIATURIZING THE AIR DAMPING EFFECT

We report a hierarchical hexahedral geometry of interdigited-comb MEMS capacitor for electrostatic vibration energy harvesters (e-VEHs), where the air damping effect is greatly reduced while the capacitance variation remains important. Based on the same frequency up-conversion structure as in our previous design, the device with the new electrode geometry reaches a larger bandwidth (10 similar to 180 Hz) in air compared to the classical gap-closing structure (80 similar to 160 Hz). The energy extracted in air during each cycle of input excitation is 85 times higher than the classical design @15Hz/2g(peak) (20 V), and is no less than 33 times higher within 10 similar to 40 Hz.