Tiny sensor nodes are the demand of smart and intelligent systems. These sensor nodes require on-board self-powered generating systems. Also, such generators should have lesser size. MEMS energy harvesters are profoundly used as the on-board self-powered generators. However, the size constrain imposes an important design trade-off on such devices. This trade-off is in-between areal dimension and the resonant frequency. In this paper, we have proposed an efficient bimorph energy harvester design which produces higher power density at very low resonance frequency. We have considered the poisonous behavior of lead-based devices as well and proposed lead-free designs in our work. The proposed design consists of a bimorph square plate of 2.25 mm² with two Zinc Oxide (ZnO) layers of 0.5 µm each sandwiched a copper electrode layer of 1 µm. A spiral cut of 5 µm thickness is made over the plate in order to form a fixed free beam structure. Furthermore, without the inclusion of tip mass, the resonant frequency of the beam is controlled by varying the number of spiral turns. Our proposed design outperformed the previous designs by producing maximum output power of 15 nW at 110 Hz with seven spiral turns with very lower active volume. Also, it has a normalized volumetric power density of 3 × 10⁻² µW/mm³ g² Hz.

微小的传感器节点是智能和智能系统的需求。这些传感器节点需要车载自供电发电系统。此外，此类发电机应具有较小的尺寸。MEMS 能量收集器被广泛用作车载自供电发电机。然而，尺寸限制对此类设备施加了重要的设计权衡。这种权衡介于面积尺寸和谐振频率之间。在本文中，我们提出了一种高效的双压电晶片能量收集器设计，可在极低的谐振频率下产生更高的功率密度。我们还考虑了含铅设备的有毒行为，并在我们的工作中提出了无铅设计。建议的设计包括一个 2.25 mm ²的双压电晶片方形板两层 0.5 µm 的氧化锌 (ZnO) 层夹着一层 1 µm 的铜电极层。在板上进行 5 µm 厚度的螺旋切割，以形成固定的自由梁结构。此外，在不包含尖端质量的情况下，光束的共振频率是通过改变螺旋匝数来控制的。我们提出的设计通过在 110 Hz 下产生 15 nW 的最大输出功率以及七个螺旋匝和非常低的有效音量而优于之前的设计。此外，它的归一化体积功率密度为 3 × 10 ^-2  µW/mm ³ g ² Hz。