Nonlinearity enhanced mode localization in two coupled MEMS resonators

Abstract

As an intriguing phenomenon in coupled dynamic systems, mode localization has garnered considerable attention in areas such as vibration control, sensing, etc. This paper investigates mode localization in two coupled MEMS resonators in both linear and nonlinear cases through experimental and theoretical analyses. The relationship of amplitude variation or energy transfer between two resonators in mode localization is unveiled. Subsequently, considering the influence of softening Duffing nonlinearity, we derive the scaling factor expression. For the first time, the experimental and theoretical results reveal that the presence of softening Duffing nonlinearity significantly enhances the sensitivity of the amplitude ratio compared to the linear case. Finally, a charge sensing scheme is proposed that utilizes nonlinear mode localization. This innovative scheme outperforms its linear counterpart, achieving an almost 5-fold increasement in charge sensing resolution. This advancement holds the potential to design high-performance sensors with significantly improved sensitivity.