Tavakkoli Hadi, Song Kui, Zhao Xu, Duan Mingzheng, Lee Yi-Kuen
Department of Mechanical and Aerospace Engineering, Hong Kong University of Science and Technology, Hong Kong, China.
School of Mechanical Engineering and Mechanics, Xiangtan University, Xiangtan 411105, China.
Micromachines (Basel). 2022 Aug 18;13(8):1342. doi: 10.3390/mi13081342.
In this paper, a new analytical method to achieve the maximum signal-to-noise ratio () of a micro search coil magnetometer (µSCM) is presented. A planar spiral inductor was utilized to miniaturize conventional bulky search coil magnetometers. First, dimensional analysis was applied to identify three dimensionless parameters for the µSCM's key performance indices (sensitivity (), noise, and ). The effect of the parameters on the µSCM's performance was carefully investigated, and a novel 4D nomogram was developed. Furthermore, an analysis considering noise sources of a low-noise amplifier was performed. By combining the results from the nomogram and the effect of the noise sources from the amplifier circuit, optimum values for the dimensionless parameters were calculated. According to the calculation results, the dominant noise source varied with an increase in the track width ratio to the outer diameter. Seven different samples were fabricated by a single-mask lithography process. The sensitivity of 1612 mV/mT was demonstrated at a 50 Hz input magnetic field, which was better than the previous µSCM ( = 6.5 mV/mT) by more than 2 orders of magnitude. Finally, one of the fabricated µSCMs was employed to measure the online power consumption of a personal computer while different types of software were running.
本文提出了一种实现微搜索线圈磁力计（µSCM）最大信噪比（）的新分析方法。利用平面螺旋电感将传统的大型搜索线圈磁力计小型化。首先，应用量纲分析来确定µSCM关键性能指标（灵敏度（）、噪声和）的三个无量纲参数。仔细研究了这些参数对µSCM性能的影响，并绘制了一种新颖的四维列线图。此外，还对考虑低噪声放大器噪声源的情况进行了分析。通过结合列线图的结果和放大器电路噪声源的影响，计算出无量纲参数的最佳值。根据计算结果，主导噪声源随轨道宽度与外径之比的增加而变化。通过单掩膜光刻工艺制作了七个不同的样品。在50Hz输入磁场下，灵敏度达到1612mV/mT，比之前的µSCM（ = 6.5mV/mT）高出两个多数量级。最后，使用制作的一个µSCM在运行不同类型软件时测量个人计算机的在线功耗。
