Bias Superposition - An On-Line Test Strategy for a MEMS Based Conductivity Sensor

A novel on-line monitoring technique for a range of MEMS and integrated sensor systems is presented based on the injection of a test stimuli into the bias structure of transducer functions. The technique "Bias Superposition" utilises both signal injection and signal extraction techniques to achieve an indication of structural integrity of the transducer and interface. The technique has been successfully applied to a thick film conductance sensor.