Design and simulation of a novel MEMS-based single proof mass three-axis piezo-capacitive accelerometer

This work presents a novel three-axis accelerometer that uses capacitive and piezoelectric sensing mechanisms. In the proposed structure, the out-of-plane accelerometer senses the vertical acceleration with a piezoelectric thin-film transducer and the lateral accelerations are sensed by differential capacitances. This structure has a size of 1 x 0.8 mm2 with a measurement range of +/- 5 g. Simulated results showed that the sensitivities (nonlinearity) of the three-axis accelerometer are 43.58 mV/g (0.18%), 48.51 mV/g (0.19%), and 1.93 mV/g (0.018%) for the x-, y-, and z-axes, respectively. Moreover, the cross-axis sensitivities of the structure are less than 1%. Brownian noises in each direction are 1.1 mu g/root Hz for the x-axis, 0.9 mu g/root Hz for the y-axis, and 1.5 mu g/root Hz for the z-axis. To validate the analytical results, they are compared with simulation results achieved by COMSOL software.