The University of Tokyo · Engineering
Professor Yuji Suzuki's research lab specializes in microelectromechanical systems (MEMS) and energy harvesting technologies, with a strong focus on developing miniaturized, efficient, and robust devices for low-power electronics. The lab pioneers innovative electret-based MEMS devices, including vibration and rotational energy harvesters, that leverage electrostatic forces and novel structural designs to enable passive, maintenance-free power generation. Key research directions include bistable energy harvesters for broadband operation, electret-based electrostatic levitation to prevent stiction, and advanced MEMS fabrication for applications in wireless sensors and structural health monitoring. The lab also explores fluidic applications, such as riblet surface effects on turbulent flows, demonstrating interdisciplinary expertise in both microsystems and fluid dynamics.
Figures are computed from collected data and may differ slightly.
Abstract Energy harvesting is a method by which energy naturally present in the environment is captured and then converted into electricity for use in low‐power electronics. Among the various energy sources, structural vibration is believed to be useful for powering wireless sensors in various applications such as sensor network and structural health monitoring. In the present paper, after a brief introduction to electret materials and charging technologies, recent progress in microelectromechan
In this paper, we propose a passive gap-spacing control method in order to avoid stiction between top and bottom structures in in-plane sensor/actuator/generator applications. A patterned electret using a high-performance perfluoro polymer material is employed to induce a repulsive electrostatic force. An out-of-plane repulsive force is successfully demonstrated with our early prototype, in both air and liquid. By using the present electret-based levitation method to keep the air gap, a MEMS ele
The structure of a turbulent flowfield along a riblet surface was investigated with the aid of a three-dimensional particle tracking velocimetry. The statistics of all three velocity components were measured and compared with those above a smooth wall. Under a drag-reducing condition, all of the turbulent velocity fluctuations and the Reynolds shear stress were decreased near the riblet surface, although the flow characteristics in most of the flowfield were quite similar to those above the smoo
This paper reports the development of MEMS rotational electret energy harvester (EH) for capturing kinetic energy of human motion. Optimal design method of rotational electret EH is proposed by considering both the rate of overlapping-area-change and the parasitic capacitance. A rotational MEMS electret EH with embedded ball bearing has been successfully developed. Up to 3.6 μW has been obtained at 1 rps rotation with an early prototype.
A MEMS electret vibration energy harvester with an embedded bistable electrostatic spring for broadband response is proposed. By using a vertical electret, the bistable potential can be realized without any complex structure or additional mechanism. Based on the 1D electrostatic model, a rigorous electromechanical model as well as an approximate model with reduced parameters are developed. Based on the normalized expression of the approximate model, which is identical to the velocity-damped reso
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