Design of a novel lower-noise tunneling magnetoresistance micromachined gyroscope

The core technology behind micromachined gyroscopes is the detection of the weak Coriolis force, the noise level of which by conventional methods has reached its limit. In this paper, an in-plane gyroscope structure based on the tunneling magnetoresistance (TMR) effect is designed providing a means to detect this force in the MEMS vibratory gyroscope. TMR is used so that a high sensitivity is achieved. From a theoretical analysis of the designed gyroscope structure, the structural sensitivity of the detection Coriolis force is obtained. A permanent magnet was designed and simulated for the TMR device and a magnet sensitivity was obtained. To obtain the magnetoresistance sensitivity, an experiment was performed to test a TMR device. A TMR gyroscope system model is implemented in the SIMULINK environment using parameter values obtained from calculations and some obtained from the experimental tests of the total sensitivity. Combining our separate results, a total sensitivity for the TMR gyroscope of 1.18 mV/°/s was obtained along with a theoretical noise floor of 9.48 × 10⁻⁵ °/s/√Hz. Therefore, the designed TMR gyroscope provides high sensitivity while achieving a lower noise level.