Sandwich Structured Flexible Thermal Shear Stress Sensor with Improved Performance

We present a micro flexible thermal shear stress sensor with sandwich structure for enhanced static sensitivity and dynamic response performance. This sandwich structure consists of a guard-heater just underneath the thermistor and electrically isolated by a Parylene C film. The working temperature of the guard-heater is identical with the thermistor to eliminate unwanted heat conduction from the thermistor to the substrate. Compared with thermistor working individually, the results of shear stress calibration test and step current characterization demonstrate a 47% increase in sensitivity and 50% reduction in time constant when the thermistor and guard-heater working simultaneously.