Simulation and characterization of dynamic contact in a MEMS passive vibration threshold sensor

A micro-machined passive vibration threshold sensor (i.e. acceleration switch) with a compliant stationary electrode has been designed, simulated and characterized. Bridge-type elastic beams as the compliant stationary electrode are adopted to improve the contact effect of the sensor. The dynamic contact between the two electrodes is simulated and analyzed by finite-element method (FEM). It is presented that a `skip contact´ phenomenon occurred during the switching on, which has been described and successfully explained in this paper. A drop hammer test of the fabricated vibration threshold sensor was done, which is in accordance with the simulated one. The measured two contact times in the skip contact are 16μs and 4μs under 55g applied acceleration shock, respectively, which are in agreement with simulated results.