Finite Element Analysis of Magnetic Shielding for a Miniaturized MEMS Displacement Sensor

Abstract

Miniaturized inductive sensors have measurement range of few millimeters and are used for accuracy within few micrometers. It is very crucial to maintain the accuracy of these sensors by magnetic shielding since their accuracy is influenced by presence of external magnetic field. In this paper study of magnetic shielding of a MEMS minimalized Linear Variable Differential Transformer (LVDT) has been presented, where pure iron has been used as the shieling material. The finite element analysis has been performed to investigate influence of external magnetic field of a permanent magnet on output voltage of the sensor. It has been demonstrated that incorporation of 300 $\mu$m thick pure iron shield spaced at distance of 5.0 mm from the sensor, ensures significant attenuation of error introduced due to presence of external magnetic field near the sensor.