TY - JOUR
T1 - A Novel Contactless DC Current Sensor Using a Highly Sensitive Thin-Film Lamb Wave Resonator With a Self-Aligned Micromagnet
AU - Gao, Wenwei
AU - Gao, Feng
AU - Zhu, Chenyao
AU - Xie, Huikai
AU - Wang, Xiaoyi
N1 - Publisher Copyright:
© 1982-2012 IEEE.
PY - 2026
Y1 - 2026
N2 - This article presents a novel resonant current sensor designed for contactless, miniaturized, high-sensitivity, and high-precision static dc current measurement. The sensor features a cantilever structure integrated with a thin-film lithium niobate lamb wave resonator (LWR) and a micromagnet. The working principle of the sensor is based on the torque and force induced by the magnetic field of the measured current, which causes a resonant frequency shift of the LWR. To integrate a 30 µm thick cantilever with a 400 nm thick LWR, a dual-mask deep silicon etching process is employed. This process ensures that the structure can support the magnet while also maintaining the resonant region as a thin film that is favorable for LWR operation. Furthermore, to ensure precise magnet placement, a self-aligning process based on the attraction between the nickel layer and the magnet is introduced. Experimental results demonstrate a sensitivity of 2.2 kHz/A, a minimum current resolution of 0.6 A in open-loop testing, and a linear measurement range of up to 70 A for dc wire measurements. These results suggest that the proposed sensor has strong potential for applications in smart meters, battery management systems (BMS), and electric vehicle charging stations.
AB - This article presents a novel resonant current sensor designed for contactless, miniaturized, high-sensitivity, and high-precision static dc current measurement. The sensor features a cantilever structure integrated with a thin-film lithium niobate lamb wave resonator (LWR) and a micromagnet. The working principle of the sensor is based on the torque and force induced by the magnetic field of the measured current, which causes a resonant frequency shift of the LWR. To integrate a 30 µm thick cantilever with a 400 nm thick LWR, a dual-mask deep silicon etching process is employed. This process ensures that the structure can support the magnet while also maintaining the resonant region as a thin film that is favorable for LWR operation. Furthermore, to ensure precise magnet placement, a self-aligning process based on the attraction between the nickel layer and the magnet is introduced. Experimental results demonstrate a sensitivity of 2.2 kHz/A, a minimum current resolution of 0.6 A in open-loop testing, and a linear measurement range of up to 70 A for dc wire measurements. These results suggest that the proposed sensor has strong potential for applications in smart meters, battery management systems (BMS), and electric vehicle charging stations.
KW - Acoustic waves resonators
KW - current measurement
KW - microelectromechanical system (MEMS)
KW - micromagnet
UR - https://www.scopus.com/pages/publications/105013593633
U2 - 10.1109/TIE.2025.3589403
DO - 10.1109/TIE.2025.3589403
M3 - Article
AN - SCOPUS:105013593633
SN - 0278-0046
VL - 73
SP - 1459
EP - 1468
JO - IEEE Transactions on Industrial Electronics
JF - IEEE Transactions on Industrial Electronics
IS - 1
ER -