MEMS VERTICAL MOTION MODULATED FLUX CONCENTRATOR FOR MINIMIZING 1/f NOISE IN GMR SENSORS

Wugang Tian - Jiafei Hu - Mengchun Pan - Dixiang Chen - Jianqiang Zhao - Guiyun Tian

   1/f noise is one of the main noise sources of giant magnetoresistance (GMR) sensors, which will cause intrinsic detection limit at low frequency. To suppress this noise, a novel vertical motion modulated flux concentrator (VMMFC) is proposed in this paper, which has high efficiency and simple structure. The flux concentrator and modulation film of VMMFC were analyzed with numeri-cal simulation. The simulation results show the modulation efficiency of VMMFC exceeds 21%. A preliminary prototype sensor based on the multi-layered GMR AA002 and VMMFC was fabricated and its modulation efficiency achieves 18.8%, which exceeds the efficiency of most existing sensors with other modulation schemes. Also, the magnetostatic detection ability is improved to 0.53 nT/√Hz.

Keywords: 1/f noise, vertical motion modulation, modulation efficiency, flux concentrator, giant magnetoresistance sensor, mag-netostatic detection ability

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