Search

Logical gates have been used in implementation of logic sequential and combinational circuits especially in computers, DSPs and microprocessors. They are mostly fabricated based on CMOS technology that provides a few nano-seconds of delay for each digital gate. Due to limitations in more scaling CMOS transistors and cause of short channel effects, some engineers and researchers believe that there is a huge demand for new devices and fabrication technologies to produce faster logic gates. In this paper, a new architecture for NAND gate is presented which operates based on mechanical resonance of a network of weakly coupled resonators that resonate in radio frequencies. This design is achieved by employing the associative memory property of Hopfield neural networks and the theory of weakly coupled resonators. The main advantage of the proposed design is in its capability to reach out delay times of the order of 1 nano-seconds or even less. One solution to decrease the delay time can be increasing the resonance frequency of resonators which are processing elements of resonators network. In this paper just the new idea of implementation NAND gate based on weakly coupled RF MEMS resonators is presented and evaluated. Other criteria like gate power consumption, effects of temperature, fan in, fan out and noise margin are not discussed. Regarding the rapid growth in MEMS technology, resonators with super high frequency (SHF 3–30 GHz) are now available and those with Extremely High frequency (EHF 30–300 GHz) will soon be in market which enables the presented design to achieve higher speeds. In addition, mechanical resonators are more fault tolerant than CMOS circuits when utilized in harsh environments which exposed to ionic beams or electron beam radiations. In space applications, the satellite and payload are exposed to huge bombardments of space electrons and ions beams. So, the proposed NAND gate can be a good solution for enhancing reliability of devices and systems exposed to space radiations. [ABSTRACT FROM AUTHOR]

In this paper, a new structure of 2D photonic crystals for all-optical 4-bit adder based on kerr effect and ring resonators is proposed. The fundamental rods are made of silicon material with a refractive index is about 3.476 around a wavelength 1550 nm. The lattice constant of the PhC structure, and the radii of fundamental dielectric rods are about 592 nm, and 118 nm, respectively. The structure is designed using in a cascade one half adder and three full adders. The optical adder is composed of nonlinear ring resonators, input ports (Ai, Bi), and output ports (Si, Ci). The ring resonators R1 and R2 based on the optical kerr effect are created by replacing 2 × 24 dielectric rods are made of nonlinear material doped glass with a linear and nonlinear refractive index of 1.4 and 10−14 m2/W, respectively. The radii of these dielectric rods are 90 nm and 80 nm. The input and output ports are located in the best position, and the total footprint is about 2229 μm2. We used COMSOL Multiphysics Software based on the plane wave expansion and the finite element methods to simulate the photonic band gap diagram and the light propagation inside the PhC structure. The proposed 4-bit adder can be used in the next generation of optical computer systems applications and photonic integrated circuit communication. [ABSTRACT FROM AUTHOR]

This research paper provides a simple and original approach to extend the resonant frequency tuning range for achieving high-to-low frequencies in electrostatically actuated microelectromechanical systems (MEMS) based resonators. In microstructures, low frequencies are usually achieved by increasing the effective mass or decreasing the mechanical stiffness. However, this work intends, assuming a double-sided electrodes design, to control the excited mode of the micro-system in order to achieve low frequencies through DC bias voltage variations and possibly eliminate the displacement dependency in capacitive micro-bridges-based structures. The design consists of a flexible microbeam where its equations of motion are derived within the framework of the nonlinear Euler–Bernoulli beam theory. The equations are then solved using the reduced-order modeling based on the Galerkin modal decomposition while considering the couple-stress theory. Simulation results show an improved performance of the proposed structure compared to previous studies. According to these results, a wide frequency tuning range has been achieved through a proper DC bias voltage arrangement. In addition, the outcomes of the numerical analysis were validated by comparing them with FEM results obtained by COMSOL software. [ABSTRACT FROM AUTHOR]

The mode localization phenomenon of the weakly coupled resonators (WCRs), which is revealed as a small asymmetric perturbation introduced in the symmetric weakly coupled resonant system will lead to a drastic variation in the system energy distribution and amplitude ratios of the resonators, has been widely used in the topology design of micro-electro-mechanical system (MEMS) sensors. In order to improve the noise characteristics of mode-localized sensors, this paper presents an optimized measurement and control system, including the frequency closed-loop system based on phase-locked loop (PLL) and the amplitude closed-loop system based on energy conservation. The vibration energy of a weakly coupled resonant system can be represented by the sum of the squares of the amplitude of each resonant unit, and the total energy of resonant units is stabilized at a constant value by the amplitude closed-loop system based on energy conservation. The proposed measurement and control system is optimized by Simulink simulation software and finally verified with the fabricated prototype of a mode-localized airflow sensor. Experiment results demonstrate that compared with the amplitude open-loop detection method, the closed-loop control scheme based on energy conservation has better bias stability, which indicates that our proposal can improve the long-term stability of output signals of the weakly coupled resonant system. [ABSTRACT FROM AUTHOR]

MEMS switches are of significant interest for promising radio-electronic systems, but have not yet found widespread use due to the low reliability of microcontacts. The switch develops a low contact force, which results in high and unstable contact resistance. The force is usually increased by using electrodes with complex shapes and large areas, but a simple and compact configuration is preferable. This study presents a switch based on a 50-µm-long cantilever. For the first time, a method for selecting the vertical dimensions of the product is described, increasing the contact force to values in excess of 100 μN, necessary for reliable operation of the contacts. Test samples are manufactured and tested, and the performance characteristics are compared with the calculation results. [ABSTRACT FROM AUTHOR]

Pumping a high-Q optical microresonator by an external laser is inevitably associated with thermal effects. They have a significant impact on the dynamics of nonlinear processes in such structures, including the generation of optical frequency combs and dissipative solitons. The generation process and the properties of bright solitons in such heated microresonators with anomalous group velocity dispersion (GVD) have been well studied, and a number of methods have been developed to minimize the effect of thermal processes. However, for dark solitons or platicons excited at normal GVD, these issues have been studied significantly less. In this work, the properties of platicons in heated microresonators are analyzed, and it is shown that in the case of "positive" thermal effects, when the direction of the thermal shift of the resonance frequencies of a microresonator coincides with the direction of the nonlinear shift, the widest high-energy platicons with the duration close to the round trip time in the resonator are stable. In the case of "negative" thermal effects, narrow low-energy platicons remain stable. Moreover, in microresonators with "negative" thermal effects, the interaction between cubic nonlinear and thermal processes can ensure the generation of platicons without special techniques required in other cases. [ABSTRACT FROM AUTHOR]

There has been a rising interest in utilizing metamaterials to manipulate the propagation of surface waves, including Rayleigh waves. These novel materials have a diverse range of applications, from micro-scale sensors and actuators to macro-scale seismic protection systems. In the field of seismic engineering, they are commonly referred to as seismic metamaterials. While various linear seismic metamaterials have been developed, incorporating nonlinearity into the design of seismic metamaterials could reveal novel phenomena and greatly expand their potential applications. In the present study, we propose a nonlinear metamaterial to block the propagation of low-frequency Rayleigh waves. The proposed metamaterial consists of a linear elastic substrate and nonlinear resonant units periodically attached to the surface of the substrate. Each resonant unit has two Duffing oscillators connected in series. We use the first-order harmonic balance method to derive analytical solutions for the dispersion of Rayleigh waves, considering both linear and various nonlinear cases. Our findings demonstrate that by coupling the motion of an elastic substrate with the dynamics of attached masses, a linear metamaterial with serial-connected resonators can achieve two band gaps. Furthermore, introducing softening nonlinearity can facilitate the attainment of a low-frequency band gap, while introducing hardening nonlinearity may result in the closure of the original linear band gaps. Our study broadens the range of applications for elastic metamaterials and potentially contributes to the development of more effective seismic wave blockers. [ABSTRACT FROM AUTHOR]

In moist air, the combined effects of temperature and relative humidity become important to discuss on the resonant frequency and quality factor of micro-electro-mechanical systems (MEMS) cantilever and bridge beam resonators. The squeeze film damping (SFD), which is the dominant energy loss of MEMS resonators, is modeled by solving the modified molecular gas lubrication (MMGL) equation, transverse vibration of micro-beam, and their appropriate boundary conditions, simultaneously by the Finite Element Modelling (FEM) in the eigen-value problem. The effective viscosity of moist air (µeff) is utilized to modify the MMGL equation taking account the combined effects of temperature and relative humidity in a wide range of gas rarefaction conditions as surface accommodation coefficients (ACs (α1 = α2)). At atmospheric pressure (p = 101,325 Pa), the SFD, which is function of temperature and relative humidity, is more dominantly than that of the other energy losses such as the thermoelastic damping (TED) and the support loss of MEMS resonators. Thus, the combined effects of temperature (T) and relative humidity (RH) are discussed on the resonant frequencies and quality factors of MEMS beam resonators in atmospheric pressure, gas rarefaction (ACs), and resonator mode. The results showed that resonant frequencies and quality factors increase as temperature and relative humidity increase at atmospheric pressure. The combined effects of temperature and relative humidity on the resonant frequency of cantilever beam are stronger than that of bridge beam. The influence of the combined effects of temperature and relative humidity on resonant frequencies and its frequency shift of MEMS resonators reduces significantly because the dominant SFD decreases as gas rarefaction increases (ACs(α1 = α2) decrease), and the resonant mode increases. [ABSTRACT FROM AUTHOR]

This paper presents a finite element method (FEM) simulation study for the frequency response analysis of a capacitive comb-drive resonator based on micro-electro-mechanical systems technology. The post-manufactured design parameters of the resonator are firstly determined after the Modified Silicon on Glass fabrication process by using the parameter extraction method. Then, these results are used to form a 3D structure of the fabricated device. Elmer FEM, an open-source finite element software for multi-physics problems, is selected within the several options for the frequency response analysis of the formed 3D structure. During the FEM analysis, an optimized mesh structure is imported to Elmer FEM for the 3D model of the resonator. Next, the frequency response analyses of the resonator are implemented with a flowchart by using Elmer FEM for a fixed AC level and various DC voltages. The parameter extraction outcomes obtained from probe test data and theoretically calculated values are crosschecked with the output of analyses obtained from the Elmer FEM. The FEM simulation results are compared with the experimental data for the frequency response analyses, the motional parameters and the motional current values as well as the rest capacitance. Furthermore, the approximation error of the simulated results of FEM analysis is calculated. Thus, the capacitive microstructures can be designed more precisely by considering expected quality factor value and fabrication-related deviations. [ABSTRACT FROM AUTHOR]

In this paper, we present a new structure of a micromachined tunable capacitor using a combination of piezoelectric and electrostatic parallel-plate actuators. Electrostatic parallel-plate capacitors have a low capacitive tuning ratio due to the "pull-in" instability. Therefore, to increase the capacitive tuning ratio, an electrostatic parallel-plate actuator, as well as a piezoelectric two-directional actuator, was used in this work. To verify the theoretical results, they were compared to the simulation results achieved by COMSOL and HFSS software. According to the analytical and simulation results, the proposed structure has a maximum capacitive tuning range of 2180% by applying 5.6 V for the electrostatic parallel-plate actuator and ± 8 V for the piezoelectric actuator. [ABSTRACT FROM AUTHOR]

Dispersion engineering of microring resonators is crucial for optical frequency comb applications, to achieve targeted bandwidths and powers of individual comb teeth. However, conventional microrings only present two geometric degrees of freedom – width and thickness – which limits the degree to which dispersion can be controlled. We present a technique where we tune individual resonance frequencies for arbitrary dispersion tailoring. Using a photonic crystal microring resonator that induces coupling to both directions of propagation within the ring, we investigate an intuitive design based on Fourier synthesis. Here, the desired photonic crystal spatial profile is obtained through a Fourier relationship with the targeted modal frequency shifts, where each modal shift is determined based on the corresponding effective index modulation of the ring. Experimentally, we demonstrate several distinct dispersion profiles over dozens of modes in transverse magnetic polarization. In contrast, we find that the transverse electric polarization requires a more advanced model that accounts for the discontinuity of the field at the modulated interface. Finally, we present simulations showing arbitrary frequency comb spectral envelope tailoring using our Fourier synthesis approach. Broadband Kerr frequency combs require engineering of the dispersion profile of the microresonator, which is challenging to do in an arbitrary fashion, due to the material dispersion and limited number of geometric control parameters of typical platforms used. The authors show and discuss the limits of an arbitrary dispersion engineering technique, based on Fourier synthesis design of photonic crystal microrings, and investigate its impact on soliton formation. [ABSTRACT FROM AUTHOR]

Aiming at resolving the contradiction between the linearity and sensitivity of capacitive pressure sensors, an analytical model and a fast design strategy are developed to achieve rapid and accurate evaluation and optimization of sensor performance on the basis of a capacitive pressure sensor with vertical comb fingers. The feasibility of the proposed model is verified by Finite Element Method (FEM) using COMSOL software. The results indicate the analytical model has good agreement with the finite element method model, and the optimal sensor has a sensitivity of 331 aF/Pa, nonlinearity error of 0.29% FS under the pressure range of 0–50 kPa. [ABSTRACT FROM AUTHOR]

Superconducting parametric amplifiers are commonly fabricated using planar transmission lines with a nonlinear inductance provided by either Josephson junctions or the intrinsic kinetic inductance of the thin film. However, Banys et al. (J Low Temp Phys, 2020) reported nonlinear behaviour in a niobium pillbox cavity, hypothesising that below T c , the pair iris-bulk resonator would act as a superconducting contact surface exploiting a Josephson-like nonlinearity. This work investigates this effect further by applying Keysight Technologies' Advanced Design System (ADS) to simulate the cavity using an equivalent circuit model that includes a user defined Josephson inductance component. The simulations show that for a resonance centred at ν 0 = 30.649 GHz, when two tones (pump and signal) are injected into the cavity, mixing and parametric gain occur. The maximum achievable gain is explored when the resonator is taken to its bifurcation energy. These results are compared to cryogenic measurements where the pump and the signal are provided by a Vector Network Analyzer. [ABSTRACT FROM AUTHOR]

The nonlinear vibration reduction in locally resonant cantilever thin plate with multi-frequency periodically distributed resonators is investigated, considering the geometric nonlinearity of the plate. Based on the von Kármán nonlinear plate theory, the strain and kinetic energy of the plated are constructed. The resonators are modeled by discrete mass–spring subsystems. The plate and resonators are combined by implementing their interactions at the connection point. The natural frequencies and modes of the cantilever plate are obtained via the Ritz method with modified characteristic functions in a linear analysis. The problem of nonlinear vibration for the locally resonant plate is discretized into a multi-degree-of-freedom system using the natural modes and Lagrange approach. The effects of multi-frequency periodically distributed resonators on the plate dynamics are demonstrated by studying the amplitude–frequency responses and the bifurcations in conjunction with the maximum Lyapunov exponents of the multi-frequency locally resonant plate. It is demonstrated that the complex nonlinear dynamic behavior of the plate in a specific frequency band can be suppressed by the periodically distributed linear resonators, and the vibration reduction over a wide frequency range can be achieved by appropriately setting the frequencies of the multi-frequency resonators. [ABSTRACT FROM AUTHOR]

In this paper, we proposed that a 3 × 8 all-optical decoder operates around 1.55 µm. We combined a 3-input port mixer (A1, A2, and A3) with an excitation port (E) and an 8-output port switch to create the proposed structure. The mixer is a square array of GaAs dielectric rods with a refractive index of 3.37. The switch is a square network of GaAs with a linear refractive index equal to 3.37 and a nonlinear Kerr coefficient equal to 1.6 × 10–17 m2/w. We controlled the switch's optical behavior via the applied optical power intensity. The switch insertion loss values are between − 0.043 and − 0.6 dB, and the maximum cross talk is between − 7.96 and − 14.62 dB. The intensity applied to the combiner input ports is 600 w/m2. In order to activate the decoder, we excited it to a power of 100 w/m2. To perform the necessary simulations, we used the finite-element method implemented in COMSOL Multiphysics software. The proposed structure works completely in the optical domain without any electronics. [ABSTRACT FROM AUTHOR]

Micro-electro-mechanical systems (MEMS)-based resonators have a wide range of current applications such as the detection of chemical and biological substances. Up to now, several studies have been done in the literature about the integration of conducting polymers with MEMS to design a sensing layer for the applications mentioned above. However, all studies have been carried out on the coating of MEMS cantilever which has some disadvantages for the mass sensor like position-depended sensing as a result of being not only a mechanical spring structure but also a proof mass. In this study, conductive polymers (CPs) have been coated on different MEMS lateral comb-drive resonator designs by an effortless and effective solution provided by the electrochemical polymerization technique for the first time in the literature. An aqueous dispersion of carboxymethyl cellulose (CMC) and pyrrole has been formed, and the PPy/CMC composite film has been homogeneously coated on the MEMS resonators by electrochemical polymerization. The integration of CPs with MEMS has not only benefited the mechanical advantages of the lateral resonator but also used optical, electrical, and functional properties of the CPs. To examine its utilization as a sensor, the designed resonators have been used in the detection of volatile organic compounds in open-air conditions. Due to the differences in intermolecular interaction according to the polymer and VOCs structure, discrimination and detection of the VOCs have been performed even in uncontrolled air conditions. [ABSTRACT FROM AUTHOR]

With the new arena of smart and Internet of things (IoT) enabled devices, a terahertz frequency-based network like 6G with high speed and low latency is required. Solid-state devices show good response till 5 GHz. However, at higher frequencies, the electromagnetic responses of these devices start to degrade. On the other hand, RF MEMS technology is matured, and devices until 30 GHz have been demonstrated. The present paper shows the advancement of RF MEMS to a new terahertz MEMS switch for 6G communication applications. The terahertz switch has an actuation voltage of 20 V with a mechanical frequency of 138.9 kHz. MEMS terahertz switch's most important factor is its high-frequency linearity. A single switch can handle all the communication bands like 2G, 3G, 4G, 5G and 6G to 150 GHz frequency. Insertion loss is less than − 0.18 dB, and isolation is more than − 20 dB from DC to 150 GHz frequency. The return loss of the switch is also better than − 23 dB for the same band. [ABSTRACT FROM AUTHOR]

This paper proposes a compact multi-bits chipless RFID tag using fully printed resonators with dual performance of tagging and sensing temperature. Each bit is modelled as curl resonator coupled to microstrip line and is printed on metal-backed Rogers RO4003 substrate. The proposed model is characterized by high attenuation of − 10 dB with narrow bandwidth and power reflection of − 3.2 dB. A parametric study on the effect of the tag dimensions of the transmission coefficient response is introduced. The resonance frequency of each bit is controlled via controlling the curl arm's length. The multi-bits RFID tag is modelled using multi-curl resonators arranged next to microstrip line with different arm lengths. A multi-bits chipless RFID tags with 3-bits, 6-bits and 12-bits are designed in the frequency band from 3 to 7 GHz. The dimensions of 6-bits code are 60 × 17 mm2 and for 12-bits code are 29.75 × 34 mm2. A temperature sensing capability is achieved via integrated Stanyl polyamide material with the curl resonator. The first bit is used for temperature sensing while the other bits are used for data encoding. The proposed chipless RFID tags are simulated using commercial software based on well defined numerical techniques; i.e. high-frequency structure simulator (HFSS) based on finite element method (FEM) and verified with CST-microwave studio (CST-MWS) based on the finite integral technique (FIT). [ABSTRACT FROM AUTHOR]

Nonlinear phenomenon is presently attracting considerable attention in the field of microelectromechanical systems (MEMS). By adjusting a controllable tuning voltage, the nonlinearity of microdevices, especially on microactuators, can be precisely manipulated. To trap and separate small particles, generating a large and stable rotation force is critical in micromanipulations. Here, we report a simple and potential angular momentum cell comprising a piezoelectric MEMS-based nonlinear multi-mode resonator with integrated electrodes. A nonlinear rotating nodal line has been observed in specific frequency bands by applying a controllable low voltage of sub 5 V on a 4-port resonator made of lead zirconate titanate (PZT) thin films. The magnitude of the actuated voltage is Complementary-Metal-Oxide-Semiconductor (CMOS)-compatible and easy to integrate with the circuit. Furthermore, the real-time rotation motion of the MEMS-based nonlinear multi-mode resonator is also verified by a laser doppler vibrometer (LDV) at both chirp and single input frequencies, respectively. Therefore, this angular momentum cell shows great potential in the application of micromanipulation. [ABSTRACT FROM AUTHOR]

The dynamic performance of a micro-resonator depends on its energy loss mechanism which is quantified by Q-factor (Quality factor). This paper presents numerical and analytical modelling techniques to understand the air damping on energy loss and Q-factor in enclosed micro-resonators. A complete finite element based numerical model is presented that can recreate a vacuum packaged MEMS resonators operating condition and capture its Q-factor for various design and pressure conditions. The finite element model was then compared with analytical models available in the literature. In this work, various vacuum regions relevant to encapsulated MEMS resonators are investigated using analytical and finite element approaches for pressure ranges of < 1 Pa, 1–10 Pa, and 10–100 Pa. When the pressure decreases, the Q factor from finite element analysis and the analytical model exponentially increases until it levels off in intrinsic damping. The modelling techniques described in this paper are compared with previously reported experimental work showing good qualitative agreement of the change in Q-factor with pressure. Air damping is divided into squeeze film damping and slide film damping to further explore damping effects and squeeze film damping is found to be the dominant energy loss mechanism in the studied device. In a gap-closing structure, the air gaps between moving structure and fixed fingers create squeeze film damping and cause energy loss while the smaller air gaps between them generate large forces, increasing the damping. The modelling techniques presented in this paper can be applied generically to MEMS resonators to mitigate air damping losses. [ABSTRACT FROM AUTHOR]

Microactuators developed from shape memory alloy (SMA) thin films on flexible substrates find good applications in MEMS design. This article presents the models of the actuation behaviour of a thin film SMA bimorph, developed by depositing CuAlNi SMA on a curved Kapton polyimide sheet substrate through a physical evaporation technique. The thermo-mechanical behaviour of the bimorph is analyzed by actuating it through Joule heating, for various inputs. During heating, the CuAlNi SMA film produces a forward displacement and in the cooling cycle, the curved flexible substrate substantiates for a bias force to recover the bimorph to its original shape, thus revealing the shape memory effect. Modelling and simulation are essential for decision making and control to involve the SMA bimorph in applications since the model help to understand the input–output performances. The article briefs about the models developed from mathematical analysis and simulation based on the physics involved in the bimorph SMA structures; analytical models of the bimorph are developed for the thermal and mechanical responses and, a simulation model is developed to obtain its actuation. The results of the models developed coincide with the experimental outputs in the actuation voltage range of 1–2.5 V. [ABSTRACT FROM AUTHOR]

Structural nonlinearity for conventional double-end fixed beam MEMS resonators considerably restricts their performance because of large displacement instabilities and excessive frequency noise. To solve this problem, a new resonator design based on H-shaped structural beams is proposed to alleviate the axial force caused by a large deflection of the beam structure. An analytical expression for the nonlinear stiffness of the proposed beam is derived using the Rayleigh–Ritz energy method. Nonlinear vibration equations of the resonant system are then formulated and solved analytically via the method of multiple scales. The results show that the H-shaped beam design can effectively reduce the nonlinearity without significantly decreasing the linear stiffness. The solution to the nonlinear stiffness of a given electrically excited resonant system is quantitatively verified by finite element analysis. The analytical solution to the nonlinear vibration of the system is verified by numerical simulation. The obtained dynamic results indicate that the H-shaped beam design can effectively improve the stability of the resonant frequency and it can also depress the cross-sensitivity of the resonator. [ABSTRACT FROM AUTHOR]

This paper proposes a novel disturbance observer (DOB) based on the free-chattering sliding-mode control (SMC) to compensate the changing of the disturbance and uncertain values of a micro-electromechanical system (MEMS) gyroscope. First, the mathematical model of the MEMS system is briefly described. Second, the SMC without the sign function was designed to deal with the problem of tracking references of the MEMS system. Due to the chattering occurs from switching control value, this paper used the sliding phase control without the sign function. Third, a DOB was proposed without the information of control inputs. To delete the conjunction of the first derivative disturbance value, a low-pass-filter was applied to drive the feedback disturbance value for compensating the perturbations of the MEMS system. Fourth, the stability of proposed control method was fulfilled the Lyapunov condition. The simulation results are used to verify the correction of the proposed theory. The effectiveness of the novel disturbance observer based on free-chattering control is a good result of tracking control performances for MEMS system. The tested disturbances and uncertainties on x- and y-axis were mostly rejected. The settling time and overshoot values are very small, the maximum settling-time value is 0.3 s. The steady-state are e x ∈ (- 10.09 , 10.03) × 10 - 4 and e x ∈ (- 13.29 , 14.88) × 10 - 4 , for x- and y-axes, respectively. [ABSTRACT FROM AUTHOR]

Over the past years, microelectromechanical systems (MEMS) have become a vital component within a wide range of technologies, making the study of their performance and operational reliability a very critical aspect for their correct functionality. Microgrippers are one such type of MEMS devices with one of their key applications being the manipulation of biological tissues and cells. This paper presents a microgripper design based on the 'hot and cold arm' electrothermal actuation mechanism that is suitable to study the deformability properties of human red blood cells under healthy and pathological conditions. The main scope of this paper is to highlight a number of failure mechanisms that are typical of surface micromachined MEMS microgrippers. These include out-of-plane buckling of the hot arm, stress concentrations, device stiction, and residual stresses. The studied polysilicon microgripper structures were designed and fabricated in line with the specifications of the commercial fabrication process PolyMUMPsTM. The microgripper design was numerically modelled and electrothermomechanically studied using finite element analysis in CoventorWare ® . Experimental testing on the fabricated structures was used to demonstrate reliable microgripper performance as well as instances of the considered failure mechanisms. Results for the reliable microgripper performance show that the microgripper arms deflected as expected when actuated, with the obtained simulation and experimental results in good agreement. The investigated failure mechanisms have led to the identification of essential design and fabrication considerations whose thorough investigation, with the aid of appropriate modelling approaches, is essential to define improvement solutions and best practices to mitigate the failure or malfunction of the microgripper during operation. [ABSTRACT FROM AUTHOR]

This paper presents a physics-based system-level compact model of a novel out-of-plane capacitive MEMS transducer for detection of mechanical forces, pressure variations or acceleration. This innovative device, which could be used e.g., as a MEMS microphone for consumer electronics applications—the use case addressed in this work—employs a capacitive read-out scheme based on a combination of plate and comb capacitors. In contrast to conventional plate capacitor transducers both electrodes of this novel device are movable. This feature results in device dynamics analogous to a weakly coupled two-degree-of-freedom oscillator system. An analysis of the governing electromechanical and fluidmechanical coupling effects is presented together with the description of the dynamics of the coupled electrodes. The proposed model, which is based on generalized Kirchoffian networks, can be simulated with the help of standard circuit simulation software. Dynamic measurements performed on two different prototype devices in a low-pressure environment are used to calibrate and validate the model. The resonance frequency shift due to electrostatic spring softening is self-consistently included in the model since the interaction among mechanical, electrical, and fluidic domain is implemented on a physical basis. The presented study also contains an analytical derivation of the dynamics of the device for the small-signal working regime. All in all, the presented analysis provides accurate physical understanding of the device, which can be employed to analyze and improve the transducer characteristics. The energy-coupled and modular modeling approach enables the extension of the model to investigate the performance of the device under the impact of the surrounding atmosphere and the effects of device packaging. [ABSTRACT FROM AUTHOR]

A micro Sagnac interferometer is proposed for electron cloud distributed sensors formed by an integrated (micro-electro-mechanical systems) MEMS resonator structure. The Sagnac interferometer consists of four microring probes integrated into a Sagnac loop. Each of the microring probes is embedded with the silver bars to form the plasmonic wave oscillation. The polarized light of 1.50 µm wavelength is input into the interferometer, which is polarized randomly into upstream and downstream directions. The polarization outputs can be controlled by the space–time input at the Sagnac port. Electrons are trapped and oscillated by the whispering gallery modes (WGMs), where the plasmonic antennas are established and applied for wireless fidelity (WiFi) and light fidelity (LiFi) sensing probes, respectively. Four antenna gains are 2.59 dB, 0.93 dB, 1.75 dB, and 1.16 dB, respectively. In manipulation, the sensing probe electron densities are changed by input source power variation. When the electron cloud is excited by the microscopic medium, the change in electron density is obtained and reflected to the required parameters. Such a system is a novel device that can be applied for brain-device interfering with the dual-mode sensing probes. The obtained WGM sensors are 1.35 µm−2, 0.90 µm−2, 0.97 µm−2, and 0.81 µm−2, respectively. The WGMs behave as a four-point probe for the electron cloud distributed sensors, where the electron cloud sensitivities of 2.31 prads−1mm3 (electrons)−1, 2.27 prads−1mm3 (electrons)−1, 2.22 prads−1mm3(electrons)−1, and 2.38 prads−1mm3(electrons)−1 are obtained, respectively. [ABSTRACT FROM AUTHOR]

A wide bandgap (BG) relates to the performance of the prevention of the elastic wave propagation of the phononic crystal (PnC) structures. The wider the BG, the higher the safety of the wave propagation isolation. For microelectromechanical systems (MEMS) resonators, suppressing anchor energy flow from the resonator body through support tethers into the substrate is a key design requirement to improve their quality factor (Q). To suppress/eliminate the anchor loss, the operating frequency of a MEMS resonator must be within the BG frequency range of the PnC. In this research, a low wide bandgap PnC strip is first proposed to support the length extensional mode MEMS resonator in improving the Q. Secondly, impacts of the geometrical dimensions on the BG of the proposed PnC trip are evaluated. Thirdly, a comparison between the proposed PnC strip and four counterparts is performed to verify the effectiveness of the proposed PnC strip in improving the Q of the resonator. The operating frequency of the resonator is 115.15 MHz. The covering BG of the resonant frequency is 96.34 MHz within 100.34–196.68 MHz. The numerical results show that the lowest BG of the proposed PnC strip is opened within 100.34–196.68 MHz which is much lower than that of the counterparts. The widest BG of the proposed PnC strip over the maximum BG of the counterparts is enhanced 168.61%. The Q of the resonator with proposed PnC strip tethers over the same one with four counterparts are boosted to 4447.21, 3952.99, 4002.62 and 85044.99%. The effectiveness of the proposed PnC strip on suppressing/eliminating anchor loss in the resonator is superior to that of four types of PnC strip counterparts. The finite element analysis (FEA) in COMSOL Multiphysics software (COMSOL) is employed to simulate the band structure and Q scenarios of the PnC strips as well as MEMS resonator. [ABSTRACT FROM AUTHOR]

This work reports highly selective multiple analyte detection by exploiting two different mechanisms; absorption and thermal conductivity using a single MEMS device. To illustrate the concept, we utilize a resonator composed of a clamped-guided arch beam connected to a flexural beam and a T-shaped moveable mass. A finite element model is used to study the mode shapes and mechanical behavior of the device with good agreement reported with the experimental data. The resonator displays two distinct out-of-plane modes of vibration. For humidity detection, we utilize physisorption by functionalizing the surface with graphene oxide (GO), which has strong affinity toward water vapors. The GO solution is prepared and drop-casted over the mass surface using an inkjet printer. On the other hand, cooling the heated flexural beams is used for helium (He) detection (thermal-conductivity-based sensor). The sensor characteristics are extensively studied when the modes are individually and simultaneously actuated. Results affirm the successful utilization of each mode for selective detection of relative humidity and He. This novel mode-dependent selective detection of multiple analytes can be a promising building block for the development of miniature, low-powered, and selective smart sensors for modern portable electronic devices. [ABSTRACT FROM AUTHOR]

The quality factor (Q-factor) is an important parameter for mechanical resonant sensors, and the optimal values depend on its application. Therefore, Q-factor control is essential for microelectromechanical systems (MEMS). Conventional methods have some restrictions, such as additional and complicated equipment or nanoscale dimensions; thus, structural methods are one of the reasonable solutions for simplifying the system. In this study, we demonstrate Q-factor control using a variable phononic bandgap by changing the length of the periodic microstructure. For this, silicon microstructure is used because it has both periodicity and a spring structure. The bandgap change is experimentally confirmed by measuring the Q-factors of mechanical resonators with different resonant frequencies. The bandgap range varies depending on the extended structure length, followed by a change in the Q-factor value. In addition, the effects of the periodic structure on the Q-factor enhancement and the influence of stress on the structural length were evaluated. Although microstructures can improve the Q-factors irrespective of periodicity; the result of the periodic microstructure is found to be efficient. The proposed method is feasible as the novel Q-factor control technique has good compatibility with conventional MEMS. [ABSTRACT FROM AUTHOR]

Wireless transmission of sensor node signal at minimum power consumption and on-site charging of batteries is the key to the success of Wireless Structural Health Monitoring (WSHM) technology. In structures like bridges, vibration-based piezoelectric energy harvesters are generally employed to convert the ambient vibrations available in the bridges into usable electrical energy. Achieving a lower resonance frequency in a compact micromachined structure is the main goal of this work. It is attempted by optimizing various parameters, including the choice of piezoelectric material used, harvester structural configuration, and conditioning of the output of the energy harvesting circuitry. The authors propose to maximize the induced stress and therefore harvested power by proposing a sectioned cantilever with gradually decreasing widths. Such a design analyzed using the analytical model developed in this work and industrial standard MEMS design tools show that two section beams employed harvesters induce more power and it is 22.8% higher than the power induced in conventional uniform section cantilever beam harvesters. With three sections it is found that it can be further improved by 42.47%. This significant improvement without compromising miniaturization is the key contribution of this work. [ABSTRACT FROM AUTHOR]

This research paper offers a simple and original approach to extend the resonant frequency tuning range from high-to-low frequencies in electrostatically actuated microelectromechanical systems (MEMS) based resonators. Typically, it is possible to achieve low frequencies in MEMS through increasing the effective mass or decreasing the mechanical stiffness in micro structures. However, this work intends, assuming a double-sided electrodes design, to control the excited mode of the micro-system in order achieve low frequencies through DC bias voltage variations and possibly eliminating the displacement dependency in capacitive micro-bridges-based structures. The design consists of a flexible microbeam where its equations of motion are derived within the framework of the nonlinear Euler–Bernoulli beam theory. The equations are then solved using the reduced-order modeling based on the Galerkin modal decomposition and while considering the couple-stress theory. Simulations show an improved performance of the micro- structure as compared to previous investigations. In addition, a wider frequency tuning range has been achieved through a proper DC bias voltage arrangement. [ABSTRACT FROM AUTHOR]

This paper presents an anchor quality factor boosted thin-film Aluminum Nitride-On-Silicon length extensional mode microelectromechanical systems (MEMS) resonator supported by phononic crystal (PnC) strip-based tethers. The proposed PnC strip is a holed circle PnC strip. This proposed resonator is compared with the same resonator supported by two types of different tethers which are named one-quarter wavelength tether and circle PnC strip tether. Furthermore, the dependence of the bandgaps (BGs) of the proposed PnC strip on its geometrical dimensions is also investigated. The quality factor (Q) of the proposed resonator is compared with that of the resonator with other tether configurations. In addition, the impacts of the number of unit cell of the proposed PnC strip on the anchor quality factor ( Q anchor ) and Q are also evaluated in this work. The designed resonator operates at approximately 133 MHz and the BG covers this resonant frequency is 33.24 MHz. The simulation results show that the Q anchor and Q of the proposed resonator achieve higher than that for the counterparts. The average Q anchor and Q of the resonator with the proposed PnC strip are superior to 1.8884 x 10 8 % and 54767.38 % over that with the circle PnC strip. These values are 4.3195 x 10 7 % and 19902.5 % as compared to the one with quarter-wavelength tether. The finite element (FE) analysis in COMSOL Multiphysics is utilized for the PnC strips and resonator simulation scenarios. MATLAB and EXCEL are applied to calculate the post processing simulation results. [ABSTRACT FROM AUTHOR]

Application of innovative technologies for the design and development of state-of-the-art weapons, enable precision aiming and maximum destruction, with minimal collateral damage. Modern warfare is based on accurate guidance and information superiority; hence next generation of weapons tends to be more reliable, intelligent, lightweight and compact. Fuze is one of the key components in the next generation of munitions. In the last two decades, MEMS-based Safety and Arming (S&A) devices were introduced to achieve fuze miniaturization and realize extended fuze functions. The use of MEMS technology for the design of fuzes based on advanced S&A devices provides the advantages like low cost, parallel processing, mass fabrication, efficient designs, and ease of system integration. With microsensors and actuators being fabricated on the single microchip, MEMS technology has revolutionized the fuze system design, yielding smart devices with microprocessors and data crosslinking ability. The efficient design of MEMS-based S&A devices for weapon fuze system is likely to shape the future of next-generation weapons. A consolidated study on MEMS-based S&A devices designed by various researchers in the past two decades is presented in this paper. MEMS S&A devices are reviewed, with special emphasis on the fabrication techniques and processes, device material and composition, sensing and actuation mechanisms and device integration with weapon fuze system. The reviewed designs of MEMS-based S&A devices are compared based on salient design features like driving principle, device composition, device size, maximum displacement etc. A comparison matrix is formulated, and logical conclusions are drawn from the work of various researchers, which can serve as a guide for future design of MEMS-based S&A devices for integration with weapons fuze systems. [ABSTRACT FROM AUTHOR]

Coupled resonator filters implemented as microelectromechanical systems (MEMS) offer performance advantages as band-pass filters at MHz frequencies. Here new designs based on resonant cavities for acoustic slow waves are developed to allow alternative frequency responses. Derivation of the lumped element model for coupled beam systems with in-plane motion from Rayleigh–Ritz perturbation theory is first reviewed. Departures from ideal behaviour caused by mechanical and electrostatic detuning are resolved. Slow wave theory is then used to develop linear array topologies with novel responses including band-stop and comb filtering with controlled filter roll-off. A systematic procedure is developed to allow rapid identification of design parameters without the need for lengthy numerical simulation, using the lumped element, stiffness matrix and finite element methods to investigate the layout parameters of initial design concepts, detailed mechanical effects and detailed electrostatic effects, respectively. High performance is demonstrated, with good agreement between the models. [ABSTRACT FROM AUTHOR]

This paper presents modelling and numerical evaluation of a piezo electrically excited clamped–clamped micro beam (CCMB) with cavity as a vibrational energy harvester. The harvester micro beam is made to vibrate at resonance by piezoelectric excitation to resemble the ambient vibration conditions. The generated voltage from the CCMB with cavity is found to be higher when compared to a similar CCMB without cavity. An analytical expression for the output voltage is derived for a particular actuation voltage at resonance and further analysis is also carried out by varying the position and thickness of the cavity to extract maximum output voltage from the CCMB harvester with and without cavity. The analytical results are well supported by numerical simulation results that are carried out in COMSOL Multiphysics FEM tool. The introduction of cavity in CCMB increases the generated peak output voltage when compared with CCMB without cavity. The proposed CCMB harvester design with cavity can also be replaced by bridge resonators in various MEMS/NEMS based sensors with piezoelectric excitation and detection. [ABSTRACT FROM AUTHOR]

In the present work, the quality factor (and thermoelastic damping) of a microbeam resonator is analyzed by employing the three-phase-lag thermoelasticity theory with memory-dependent derivative. We compare our results with different heat conduction models. An explicit formula of thermoelastic damping has been derived, and effects of the normalized frequency and the beam height on thermoelastic damping of the microbeam resonator have been studied. We presented our work numerically by taking Silicon. The effects of normalized frequency, beam height, and different kernel of memory-dependent derivative on thermoelastic damping has been presented with the numerical data of Silicon. [ABSTRACT FROM AUTHOR]

In this paper, we report a new design of an all-optical full-adder using two nonlinear resonators. The PhC-based full-adder consists of three input ports (A, B, and C for input bits), two nonlinear resonant cavities, several waveguides, and two output ports (for the SUM and CARRY). Eight silicon rods and a nonlinear rod composed of doped glass form each resonant cavity. The well-known plane wave expansion technique is used to calculate the photonic band structure. It shows a wide photonic bandgap in the wavelength range of 1365–2074 nm covering the C and L optical transmission bands. The finite-difference time-domain method is applied to study the light propagation inside the full-adder. Our numerical results demonstrate when the incoming light intensity increases, the nonlinear optical Kerr effect appears and controls the direction of light emitted inside the structure as desired. The maximum time delay and footprint of the proposed full-adder are about 3 ps and 758.5 μm2, respectively. Therefore, due to the low time delay and small footprint, the presented design can be used as a basic mathematical operator in the all-optical arithmetic logic unit. [ABSTRACT FROM AUTHOR]

In the framework of the nonsecular perturbation theory based on the Bogoliubov averaging method, an optomechanical system with an asymmetric anharmonic mechanical resonator is studied. The cross-Kerr interaction and the Kerr-like self-interaction of photons and vibration quanta arise in the Hamiltonian. These interactions are induced by both cubic and quartic nonlinearities of oscillations of the mechanical resonator and the cavity–resonator coupling that is linear in mechanical displacements. We demonstrate a bistable behavior of the number of vibration quanta and find that this behavior is controlled by the cross-Kerr interaction. It is shown that, without driving and dissipation, the constructed superposition Yurke–Stoler-like states of the cavity (or the mechanical resonator) disentangle at certain times the entangled modes of the system. The obtained results offer new possibilities for control of optomechanical systems with asymmetric mechanical oscillations. [ABSTRACT FROM AUTHOR]

The main goal of this study addresses the synchronization between two MEMS resonators with cubic and quintic mechanical stiffness under the existence of system uncertainties and external disturbances. The synchronization is obtained by using a novel adaptive time-varying terminal sliding mode control scheme, which includes three time-varying feedback gains can tackle the nonlinear dynamics. Meanwhile, the time-varying feedback gains are updated according to suitable adaptive rules without known bounds of system uncertainties and external disturbances in advance. Based on the Lyapunov stability theory, sufficient conditions to ensure the convergence of the errors between the outputs of master and slave MEMS systems are proven and numerical studies are performed. [ABSTRACT FROM AUTHOR]

Resonance nano biosensors are electrostatically actuated sensors that recognize an analyte which is defined as the objective substance. These sensors take advantage of the vibrational characteristics such as the effect of analyte inertia on the natural frequency. In most of the previous studies, the analyte is modeled as a point-mass. This study focuses on more realistic distributions on the surface of micro/nano transducers. Gaussian function (normal distribution), as well as a uniform mass distribution, are inspected and compared with the point-mass model. A non-dimensionalized (ND) form of Euler–Bernoulli beam theory is employed whilst an electrostatic field acts on the biosensor. Two FEM algorithms and a dynamic solution are presented for the added mass to cantilevered nano-wire biosensors. Also, the effect of mass quantity and the length of distribution for Gaussian and uniform mass distributions are examined and compared with the point-mass model. Results signify the importance of analyte distribution shapes due to the resonance frequency shift. [ABSTRACT FROM AUTHOR]

High-precision micro shell resonator fabricated from the micro glassblowing process shows great potential in inertial sensors with acceptable cost. The finite-element analysis indicates that the 4th radius and thickness harmonic of geometric imperfections significantly increases frequency split of resonator. In order to investigate more details about the rapidly high-temperature molding of glass, a two-dimensional axisymmetric model and a three-dimensional shell model are built based on a numerical approach. The common sources of imperfections in the fabrication are analyzed including non-planarity of initial fused silica substrate's surface, non-circularity of mold and misalignment of blowtorch with respect to mold. First, the simulation results show that different shell contours form from the fused silica substrates with nonuniform thickness, which affects the physical parameters of resonator, such as angular gain and anchor loss. The case that four protrusions or depressions evenly distributed on the circumference of the fused silica substrate is believed that will cause severe frequency split of resonator. Second, the results show that the non-circularity of the mold completely reproduce at the rim of resonator through the molding process, which is another source of the frequency split. However, the mapping effect gradually declines along the axis of shell. Finally, height variation along the circumference is generated due to the misalignment error of blowtorch. Radial uniform heat flux is considered to be helpful to improve the robustness to misalignment. [ABSTRACT FROM AUTHOR]

This paper proposes a new all-optical full-adder design based on nonlinear X-shaped photonic crystal (PhC) resonators. The PhC-based full-adder consists of three input ports, two X-shaped PhC resonators (X-PCRs), and two output ports. The dielectric rods made of silicon and nonlinear rods composed of doped glass are used to design the X-PCRs. Two well-known plane wave expansion and finite difference time domain methods are applied to study and analyze the photonic band structure and light propagation inside the PhC, respectively. Our numerical results demonstrate when the incoming light intensity increases, the nonlinear Kerr effect appears and manages the direction of light propagation inside the structure. The maximum time delay and footprint of the proposed full-adder are about 2.5 ps and 663 μm2, making it an appropriate adder for high-speed data processing systems. [ABSTRACT FROM AUTHOR]

In this paper, we have designed an optimal design of microelectromechanical (MEMS) resonator. The paper explains the idea of suitable design, modeling and optimization of the MEMS RF resonator. The resonator has been designed to achieve a high quality factor and optimum pull in voltage and keeping the dimension as small as possible. The design approach uses the Dragonfly algorithm for minimizing the pull in voltage. The resonator is basically a perforated structure incorporating circular holes. [ABSTRACT FROM AUTHOR]

This study discusses the exploitation of a full-3D methodology for the electromagnetic simulation of a Wafer-Level Packaging solution featuring Through Silicon Vias (TSVs) for the redistribution of electrical signal from the in-package (RF-MEMS) passive devices to the external world. In particular, the Finite Element Method full-3D model is parameterised and allows analysing the influence of the most relevant Degrees of Freedom (DoFs) available in the package design, on the RF characteristics of encapsulated RF-MEMS passive devices. A previous part of this work, already published, discussed the validation of the mentioned full-3D model, comparing the results of simulations against experimental S-parameters datasets for a certain variety of Coplanar Waveguide test structures, in a frequency range from 50 MHz up to 30 GHz. Such a comparison showed good accuracy in predicting the behaviour of physical devices. Therefore, the soundness of the optimisation approach can be regarded as proven and consolidated for the optimisation purposes of the current work. [ABSTRACT FROM AUTHOR]

In this paper, a fuzzy stability control algorithm based on the type-2 sequential fuzzy neural network (T2SFNN) is proposed to suppress the chaotic motion of the MEMS resonator. The dynamical behaviors of the MEMS resonator are revealed by the bifurcation diagram, exponent diagram, phase diagram and corresponding time history. In the process of the controller design for backstepping control, the T2SFNN is used to tackle the unknown external disturbance and eliminate the effect of time delay, along with the cosine function to ensure that the output constraint is not violated. In addition, an absorber is employed to avoid the repeated derivative associated with the backstepping. Finally, the effectiveness of the proposed scheme is verified by numerical simulation. [ABSTRACT FROM AUTHOR]

Packaging of Radio Frequency MicroElectroMechanical-Systems (RF-MEMS) and other passive components is a delicate issue, especially in the riverbed of upcoming application contexts like 5G and the Internet of Things, in which frequencies of operation are getting closer to mm-Waves (millimetre waves). In fact, when dealing with RF signals, the package, beyond protecting encapsulated devices, has also to exert an influence as limited as possible on their electromagnetic characteristics and performance. Therefore, the package design phase has to be performed with particular care. Given such a frame of reference, this study discusses the validation against experimental data of a full-3D methodology for the electromagnetic simulation of a Wafer-Level Packaging solution featuring Through Silicon Vias for the redistribution of electrical signal from the in-package (RF-MEMS) passive devices to the external world. In particular, the results of the full-3D finite element method RF simulations will be compared against experimental S-parameters datasets for a certain variety of Coplanar Waveguide test structures, in a frequency range from 50 MHz up to 30 GHz, showing good accuracy in predicting the behaviour of physical devices. For the sake of brevity, this work will be followed by a standalone second part in which the full-3D model, here validated, will be parameterised and exploited to analyse the influence of the most relevant Degrees of Freedom available in the package design, on the RF characteristics of encapsulated RF-MEMS passive devices. [ABSTRACT FROM AUTHOR]

The ever-increasing demand for microelectromechanical systems (MEMS) in modern electronics has reinforced the need for extremely accurate analytical and reduced-order models to aid in the design of MEMS devices. Many MEMS designs consist of cantilever beams with a tip mass attached at the free end to act as a courter electrode for electrical actuation. One critical modeling aspect of electrically actuated MEMS is the electrostatic force that drives these systems. The two most used representations in the literature approximate the electrostatic force between two electrodes as a point force. In this work, the effects of the representation of the electrostatic force for electrically actuated microelectromechanical systems are investigated. The system under investigation is composed of a beam with an electrode attached to its end. The distributed force, rigid body, and point mass electrostatic force representations are modeled, studied, and their output results are compared qualitatively. Static and frequency analyses are carried out to investigate the influences of the electrostatic force representation on the static pull-in, fundamental natural frequency, and mode shape of the system. A nonlinear distributed-parameter model is then developed in order to determine and characterize the response of electrically actuated systems when considering various representation of the electrostatic forces. The results show that the size of the electrode may strongly affect the natural frequencies and static pull-in when the point mass, rigid body, and plate representations are considered. From nonlinear analysis, it is also proven that the representation may affect the hardening behavior of the system and its dynamic pull-in. This modeling and analysis give guidelines about the usefulness of the electrostatic force representations and possible erroneous assumptions that can be made which may result in inaccurate design and optimal performance detection for electrostatically actuated systems. [ABSTRACT FROM AUTHOR]

Simulation of MEMS-based, microelectromechanical-systems, radio frequency (RF) passive components, i.e. RF-MEMS, is not an easy task, as it involves the coupling of different physical domains (mechanical, electrical, electromagnetic). This work discusses the exploitation of a software library of elementary MEMS behavioural models, in order to predict the multi-physical behaviour of a complex RF-MEMS switch geometry, i.e. a toggle-switch. The elementary models developed and available in the software library are implemented in an HDL (hardware description language) programming code and can therefore be exploited within standard development environments for integrated circuits. [ABSTRACT FROM AUTHOR]

During gas measurement, there is a mass change of resonator in a micro-resonant gas sensor. If the design parameters are not selected rightly, there will be obvious vibration state change or even chaotic vibration during gas measurement. Here, using multi-field coupled nonlinear dynamics model considering mass change during gas adsorption and desorption, the nonlinear dynamics performance and chaotic vibration of the gas sensor are investigated. Effects of the initial clearance between resonator and base, excitation voltage and dynamic viscosity of the gas on the vibration states are analyzed. Considering mass change during gas adsorption and desorption, the stability intervals of the initial clearance, excitation voltage and dynamic viscosity of the gas are determined. Besides it, a proportional differential control link is used to tune the vibration state of the sensor. Results show that when mass change during gas adsorption and desorption is considered, the stability intervals of the initial clearance, excitation voltage and dynamic viscosity of the gas are reduced. To obtain stable operation performance, these parameters of the sensor should be selected properly. A proportional differential control link can tune the vibration state of the sensor easily. [ABSTRACT FROM AUTHOR]

A micro-electromechanical resonator, consisting of a 125 × 125 μ m 2 center plate suspended 2 μ m above a substrate, was immersed in 4 He along with a quartz tuning fork. The tuning fork was placed 5 mm above the resonator and was used to generate turbulence. The damping of the resonator was investigated in the presence of turbulence generated by the tuning fork. We observe a velocity, v c ≃ 5 mm s - 1 , above which the damping on the resonator is drastically reduced for all tuning fork velocities studied. We attribute this change in damping to the shedding and capture of vortices. [ABSTRACT FROM AUTHOR]