Comparison analysis of energy loss between micro clamped-clamped and clamped-free beam in vertical motion flux modulation magnetic sensor

摘要

The 1/f noise is one of the main noise sources of giant magnetoresistive sensors, which will cause intrinsic detection limit at low frequency. To suppress this noise, a vertical motion flux modulation (VMFM) integrated with simple microelectromechanical-systems (MEMS) structure is proposed. However, the energy loss of VMFM structure is not considered yet. In this paper, energy loss between MEMS clamped-clamped beam (C-C beam) and clamped-free beam (C-F beam) used as VMFM structure are compared. In this comparison, quality factor (Q) is proposed to characterize the energy loss of the VMFM structure. Theory analysis and experimental results show that quality factor of a C-C beam is higher than that of a C-F beam, indicating a lower energy in VMFM. Finally, the sensitivity of a VMFM magnetic sensor modulated by a C-C beam is tested, and the sensitivity gets 3.85 mV/V/Gs.