Modifying Geometry to Enhance the Performance of Microcantilever-Based Acoustic Sensors

This letter reports on a simplistic approach for significantly enhancing the mass sensitivity of microcantilever acoustic sensors by modifying the cantilever geometry. The approach involved modifying the geometry to minimize the effective mass at the free end of the microcantilever. Polystyrene beads were attached at specific locations and the resonant behavior and mass sensitivity was compared between geometries. Resonance behavior was assessed via the laser reflection method. Mass sensitivity was found to increase by nearly an order of magnitude for the new geometrical shapes over the rectangular geometry, which is the standard shape for microcantilever acoustic sensors. Triangular geometries yielded the best performance increase over the standard rectangular geometry; however a compromise was made to ensure there was sufficient area at the microcantilever free end to capture target species in frequency shift by mass addition applications.