Towards electromechanical computation: An alternative approach to realize complex logic circuits

Electromechanical computing based on micro/nano resonators has recently attracted significant attention. However, full implementation of this technology has been hindered by the difficulty in realizing complex logic circuits. We report here an alternative approach to realize complex logic circuits based on multiple MEMS resonators. As case studies, we report the construction of a single-bit binary comparator, a single-bit 4-to-2 encoder, and parallel XOR/XNOR and AND/NOT logic gates. Toward this, several microresonators are electrically connected and their resonance frequencies are tuned through an electrothermal modulation scheme. The microresonators operating in the linear regime do not require large excitation forces, and work at room temperature and at modest air pressure. This study demonstrates that by reconfiguring the same basic building block, tunable resonator, several essential complex logic functions can be achieved. Published by AIP Publishing

A 2:1 MUX based on multiple MEMS resonators

Micro/nano-electromechanical resonator based mechanical computing has recently attracted significant attention. This paper reports a realization of a 2: 1 MUX, a concatenable digital logic element, based on electrothermal frequency tuning of electrically connected multiple arch resonators. Toward this, shallow arch shaped microresonators are electrically connected and their resonance frequencies are tuned based on an electrothermal frequency modulation scheme. This study demonstrates that by reconfiguring the same basic building block, the arch microresonator, complex logic circuits can be realized. (C) 2016 The Authors. Published by Elsevier Ltd

Activating internal resonance in a microelectromechanical system by inducing impacts

As natural frequencies become commensurate, internal (autoparametric) resonances involving the corresponding modes may arise. This phenomenon has been recently increasingly reported in micro- and nanosystems. Due to the intrinsic nonlinearity, internal resonances may draw complex features, which can be desirable for developing novel devices with enhanced functionality based on energy transfer among the involved modes. Here, we examine the possibility of activating internal resonance by inducing impacts. Through a specially deposited dielectric layer to prevent short-circuiting, a microelectromechanical beam is deliberately operated to have impact with the substrate, which redirects the dynamics of the system. Driven by repetitive impacts, the device widens the frequency bandwidth around the first mode and activates a non-classical type of internal resonance, at a ratio of 7:2 between the first and third vibration modes. Interestingly, this internal resonance behavior is enabled in regions of the driving parameters space, where the branch would not have existed in the absence of impacts. The dynamical phenomena featured by the impacts are affected by the characteristics of the impacting surfaces, which may controllably tune the response. This study opens up research toward utilizing impacts for favoring internal resonance activations, including in cases where they are precluded in the smooth system, as well as engineering the associated modal energy exchange

Microelectromechanical reprogrammable logic device

In modern computing, the Boolean logic operations are set by interconnect schemes between the transistors. As the miniaturization in the component level to enhance the computational power is rapidly approaching physical limits, alternative computing methods are vigorously pursued. One of the desired aspects in the future computing approaches is the provision for hardware reconfigurability at run time to allow enhanced functionality. Here we demonstrate a reprogrammable logic device based on the electrothermal frequency modulation scheme of a single microelectromechanical resonator, capable of performing all the fundamental 2-bit logic functions as well as n-bit logic operations. Logic functions are performed by actively tuning the linear resonance frequency of the resonator operated at room temperature and under modest vacuum conditions, reprogrammable by the a.c.-driving frequency. The device is fabricated using complementary metal oxide semiconductor compatible mass fabrication process, suitable for on-chip integration, and promises an alternative electromechanical computing scheme

Experimental and theoretical investigation of the 2:1 internal resonance in the higher-order modes of a MEMS microbeam at elevated excitations

We analyze the dynamics induced by a 2:1 internal resonance between the third (second symmetric) and the fifth (third symmetric) mode of a MEMS microbeam. An extensive experimental investigation is conducted, where forward and backward sweeps are systematically acquired up to elevated excitations. As ramping the voltage, a change along the forward sweep of the resonant branch is noted. This is analyzed via the combined use of different analytical and numerical tools, which show a phase shift between the modes involved in the 2:1 internal resonance. Constantly referring to the experimental data, simulations examine the underlying features of the system's behavior. The dynamics observed in the experimental frequency sweeps are part of a more complex scenario, where different attractors appear and coexist. The experimental behavior bifurcation chart is reported and compared with simulations, which offers a comprehensive view of the 2:1 internal resonance activation. The concurrence of numerical results and experimental data confirms on the effective actuality of these complex features in safe conditions, along wide ranges of the parameters space

Internal resonance in the higher-order modes of a MEMS beam: experiments and global analysis

This work investigates the dynamics of a microbeam-based MEMS device in the neighborhood of a 2:1 internal resonance between the third and fifth vibration modes. The saturation of the third mode and the concurrent activation of the fifth are observed. The main features are analyzed extensively, both experimentally and theoretically. We experimentally observe that the complexity induced by the 2:1 internal resonance covers a wide driving frequency range. Constantly comparing with the experimental data, the response is examined from a global perspective, by analyzing the attractor-basins scenario. This analysis is conducted both in the third-mode and in fifth-mode planes. We show several metamorphoses occurring as proceeding from the principal resonance to the 2:1 internal resonance, up to the final disappearance of the resonant and non-resonant attractors. The shape and wideness of all the basins are examined. Although they are progressively eroded, an appreciable region is detected where the compact cores of the attractors involved in the 2:1 internal resonance remain substantial, which allows effectively operating them under realistic conditions. The dynamical integrity of each resonant branch is discussed, especially as approaching the bifurcation points where the system becomes more vulnerable to the dynamic pull-in instability

Global Analysis and Experimental Dynamics of the 2:1 Internal Resonance in the Higher-Order Modes of a MEMS Microbeam

In this work, we consider a MEMS microbeam, and we investigate the experimental response of the device at the third-mode dynamics. By forward and backward sweeping, the data acquired via the laser Doppler vibrometer show the occurrence of a 2:1 internal resonance, where the coupling mode is the fifth. The experimental response is simulated via shooting technique and attractor basins. We focus on the metamorphoses of the basins of attraction scenario induced in the phase space by the activation of the internal resonance

Two-to-one internal resonance in the higher-order modes of a MEMS beam: Experimental investigation and theoretical analysis via local stability theory

The present study is focused on the dynamics of a microbeam-based MEMS device and analyzes its behavior in the neighborhood of the third natural frequency. An extensive experimental investigation is conducted. The main resonant and non-resonant branches span a wide range of coexistence. The 2:1 internal resonance is activated between the third and fifth modes, in which case the device exhibits complex and intriguing dynamics. The experimental data are examined in depth using various analytical and numerical tools. Alongside with the experiments, theoretical simulations are developed, where the main features of the internal resonance are properly represented and the contribution of each mode is discussed. The main steps of the progression of the 2:1 internal resonance are highlighted and the possibility of more complex internal resonances is explored, where different higher modes are involved