Ultra-Sensitive Minute Mass Sensing Using a Microcantilever Virtually Coupled with a Virtual Cantilever

Abstract

Mass sensors based on the eigenmode shift of coupled cantilevers achieve much higher sensitivity than those based on the single cantilever’s eigenfrequency shift. In the former sensors, two identical cantilevers and a weak coupling stiffness between them are required to achieve high sensitivity. However, conventional coupled cantilevers cannot satisfy these requirements because of machining accuracy. To satisfy both requirements, a virtual coupling between a real macrocantilever and a virtual cantilever, whose dynamics was calculated using a digital computer, was proposed in our previous research. The sensitive mass sensing of mg-order masses was achieved. In the present work, for minute mass sensing, we replace the real macrocantilever with a real microcantilever. The calculation speed of a digital computer is not fast enough to calculate the virtual cantilever’s dynamics because the natural frequency of the microcantilver is much higher than that of the macrocantilever. Therefore, we use an analog circuit instead of a digital computer to achieve virtual coupling with the virtual cantilever. The proposed system enables us to tune the virtual cantilever’s parameters to satisfy both requirements for high sensitivity by changing the analog circuit parameters. We verified experimentally that the proposed system achieved high sensitivity for mass sensing of the order of nanograms.

Platform for Weakly Coupled Electro-Mechanical Resonators with Arbitrary Tunability

“…Resonator R 2 is a tunable RLC electrical resonator made up of lumped components. The coupling logic is built with analog operation circuits [6], which realizes fully electrical coupling. It has a coupling factor k c /k ranging from 0 to 1. circuits [6], which realizes fully electrical coupling.…”

“…The coupling logic is built with analog operation circuits [6], which realizes fully electrical coupling. It has a coupling factor k c /k ranging from 0 to 1. circuits [6], which realizes fully electrical coupling. It has a coupling factor 𝑘 /𝑘 ranging from 0 to 1.…”

An asymmetric mode-localized mass sensor based on the electrostatic coupling of different structural modes with distributed electrodes

“…Other methods to improve the sensitivity and stability of mode localization sensors have also been studied. Kasai et al [25] used a virtual cantilever beam coupled with a real cantilever beam to complete nanogram-level mass sensing, which is 10 times more sensitive than single cantilever resonator. Li et al [26] investigated the nonlinear bifurcation behavior of electrostatically coupled resonators.…”

Design of active network filters as hysteretic sensors

“…In [24], self-excitability and parameter hysteresis are leveraged to develop a vibrational viscometer with improved performance relative to traditional sensor designs relying on frequency-response analysis. Coupling between a physical micro-cantilever and a virtual cantilever simulated by an analog circuit is used in [12] to achieve high-sensitivity mass measurements of tens of nanograms.…”