Ultrasensitive mass detection using dual-microcantilevers coupled by cruciform overhang

This paper reports the use of dual-microcantilevers coupled by cruciform overhang to enhance the mass sensitivity for minor mass detection. Driven by a piezoactuator in air, each cantilever of the structure can resonate in two different modes (in-phase and out-of-phase modes), and the resonant amplitude-ratios are compared before and after a mass adding. Using this sensing strategy, the cross-shaped overhang of the coupled system, by weakening the coupling effect between the two cantilevers, provides two orders of magnitude enhancement in mass sensitivity without scaling down the cantilevers.