This work presents a test method for capacitive Micro-Electro-Mechanical Systems (MEMS). A major class of MEMS sensors operate based on the principle of capacitance variation.The proposed test method in this work utilizes a resonant circuit to detect structural defects of capacitive MEMS sensors. It is shown that a small variation of MEMS capacitance due to a defect alters the resonance frequency considerably. It is also shown that the variation of the output amplitude can be observed for fault detection if an inductor with a high quality factor is employed in the test circuit. Mathematical approach is taken and verified to prove the validity of this work. The effects of structural defects such as short, broken and missing fingers of the MEMS comb-drive on the equivalent circuit models have been determined through frequency domain simulations.Simulation results and experimental measurements using an implemented MEMS comb drive indicate that the proposed method can detect common faults such as missing, broken and short fingers.
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