Density Measurement Using a Self-Excited Stainless-Steel Microcantilever With Electrostatic Force Actuation

Abstract The present study proposes liquid density measurement using a self-excited microchannel resonator made of stainless steel. The sensor is made with metal etching and diffusion bonding. Thus, it enables us to reduce the sample amount compared to macroscale sensors while being easier to fabricate than MEMS. We propose using electrostatic force to excite the stainless-steel microcantilever directly to eliminate the dynamic coupling between a microcantilever and its holder. The actuation is applied under nonlinear velocity feedback control through voltage to employ the dynamics of the Rayleigh oscillator. The proposal’s validity is confirmed by distinguishing distilled water, ethanol, and salty water one by one. We observed distinguishable frequency shifts of self-excitation in the experiments.