Mode-Split MEMS Gyroscopes Under Bending Stress: Detection Mode Coupling and the Relation to Cross-Axis Sensitivity

In this work, the detection mode coupling of multi-axis MEMS gyroscopes is investigated in theory and experiment. First, the impact of bending stress on the transfer behavior of the detection modes is evaluated by actuating the modes with test signals. It is shown experimentally, that by applying bending stress, the mode coupling is significantly increased. Additional to that, cross-axis sensitivity (CAS) is measured with the same setup. In the second part of the paper, theoretical descriptions of the detection mode coupling are developed. By comparing the experimental results with the theory, it is demonstrated, that spring coupling is the dominant coupling mechanism that induces the mode coupling with bending stress. In this work, cross-axis sensitivity is investigated with respect to bending stress and a further aspect towards understanding the origins of cross-axis sensitivity is provided.