A fluid viscosity sensor with resonant trapezoidal micro cantilever

A MEMS (Micro-electro-mechanical systems) fluid viscosity sensor with resonant trapezoidal micro cantilever is introduced in this paper. The fluid viscosity can be measured through the relationship between the fluid viscosity and the quality factor, the resonant frequency of the micro cantilever immersed in the fluid. In order to improve the sensitivity of the viscosity sensor, the geometry of the sensor chip should be carefully designed. Rectangle and trapezoidal micro cantilever chip with different lengths are proposed. The first resonant frequencies and harmonic response analyses of two sensor chips are carried out with ANSYS software. And the quality factors of the sensor chips are calculated through Matlab software. The simulation results show that the resonant frequency and quality factor of trapezoidal cantilever are higher than that of rectangular cantilever with the same length. Therefore, the viscosity sensor with trapezoidal micro cantilever has a better performance. The experimental results show that the viscosity sensor with trapezoidal micro cantilever has a fine accuracy to measure the viscosity of toluene.