Froemel Joerg, Akita Satoru, Tanaka Shuji
Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
Department of Robotics, Tohoku University, 6-6-01, Aza Aoba, Aramaki Aoba-ku, Sendai 980-8579, Japan.
Micromachines (Basel). 2020 Jun 30;11(7):649. doi: 10.3390/mi11070649.
A simple micro-machined pressure sensor, based on the stress-impedance (SI) effect, was fabricated herein using typical micro-fabrication technologies. To sense pressure, a 1-µm thin, soft magnetic metallic film of FeSiB was sputtered and used as a diaphragm. Its electrical response (impedance change) was measured under pressure in a frequency band from 5 to 500 MHz. A lumped-element equivalent electric circuit was used to separate the impedance of the soft magnetic metal from other parasitic elements. The impedance change clearly depended on the applied pressure. It was also shown that the impedance change could be explained by a change in relative permeability, according to the theory of the SI effect. The radial stress in the diaphragm and the relative permeability exhibited a linear relationship. At a measurement frequency of 200 MHz, the largest sensor response, with a gauge factor of 385.7, was found. It was in the same order as the conventional sensors. As the proposed device is very simple, it has the potential for application as a cheap pressure sensor.
本文采用典型的微加工技术制造了一种基于应力阻抗（SI）效应的简单微机械压力传感器。为了感应压力，溅射了一层1μm厚的FeSiB软磁金属薄膜并用作隔膜。在5至500MHz的频带内，在压力作用下测量其电响应（阻抗变化）。使用集总元件等效电路将软磁金属的阻抗与其他寄生元件分离。阻抗变化明显取决于施加的压力。根据SI效应理论，还表明阻抗变化可以用相对磁导率的变化来解释。隔膜中的径向应力与相对磁导率呈线性关系。在200MHz的测量频率下，发现最大的传感器响应，应变片系数为385.7。它与传统传感器处于同一量级。由于所提出的器件非常简单，它具有作为廉价压力传感器应用的潜力。
