Enhanced complexity of chaos in micro/nanoelectromechanical beam resonators under two-frequency excitation

Abstract

Suspended beam micro/nanoelectromechanical (MEMS/NEMS) resonators are relevant potential sources of chaotic signals for many practical applications due to their low power consumption and high operating frequencies. However, chaos is generally restricted to small regions of the parameter space when MEMS/NEMS resonators are driven by a single frequency, as considered so far in most of the literature and all experiments. It has recently been found that strong chaotification and robust chaos (characterized by a chaotic attractor insensitive to changes on the system parameters) can emerge in the resonators when excited by two distinct frequencies. Here we show that this strong chaotification not only increases the regions in the parameter space with chaos, but also enhances the complexity of the chaotic dynamics. These findings make MEMS/NEMS resonators even more attractive for practical applications. The increase in complexity is demonstrated through the analysis of the Fourier spectrum and the use of recurrence quantification analysis (RQA). A larger entropy of the Fourier spectrum and lower determinism are obtained compared to the single frequency excitation as the amplitude of the second frequency increases.