Microfabricated shear stress sensors, Part 2: Testing and calibration

Three designs of surface-micromachined shear stress sensors have been tested and calibrated in a continuum how channel, The first design, for moderate shear stress conditions, is composed of passive sensors with optically determined sensitivities of 9 and 5.5 Pa/mu m of Boating-element deflection for two variants. The second-generation design features Boating elements integrated with on-chip electronics. The deflection is thus measured with a voltage output that displays significant nonlinearities due to the limitations of drive electronics. Complete calibration of the third design was performed, as these sensors were integrated with complex active element control circuitry. These devices demonstrated a device sensitivity of 1.02 V/Pa +/- 5% over a sensor range of 0.5-3.7 V.