Highly symmetric tri-axis piezoelectric bimorph accelerometer

This paper describes the design, fabrication and test results of a novel bimorph tri-axis piezoelectric accelerometer (built on symmetric quad Parylene beams with ZnO film). Because of its highly symmetric quad-beam bimorph structure and single proof mass, this tri-axis piezoelectric accelerometer has high sensitivity, low cross-axial sensitivity, good linearity and compact size. The un-amplified sensitivities of the X, Y and Z-axis electrodes in response to accelerations in X, Y and Z-axis are 0.93 mV/g, 1.13 mV/g and 0.88 mV/g, respectively. The minimum detectable signal is measured to be 0.04 g over a subHz ∼100 Hz bandwidth. The cross-axial sensitivity among the X, Y and Z-axis electrodes is less than 15%.