Mohammad Ibrahim Younis

• Professor (Full) at Binghamton University

We present a new approach to enhance the sensitivity of resistive sensors and enable threshold switching that can be used for actuation, providing a simple binary readout method. The concept is based on electrically coupling a resistive sensor with a resonant MEMS structure. Results are demonstrated for two case studies involving a resistive temper...

In this work, we present an investigation into the 2:1 internal resonance and saturation phenomena in a compound micromachined U-shaped portal frame MEMS device and its potential exploitation for gas detection. The portal frame design accounts for the quadratic geometric nonlinearity, which yields mode coupling between the first and second modes of...

This paper reports a low-g in-plane MEMS inertial switch with multiple acceleration thresholds in multiple sensing directions. Designed for essential monitoring, this device targets low-g accelerations for health and safety applications. The device design utilizes the standard silicon-on-insulator micromachining process (SOIMUMPs) to simplify both...

This article reports an ultrasensitive low-to-medium vacuum pressure sensor based on an electrothermally tuned and electrostatically actuated resonant microstructure. The concept is based on tracking the frequency difference shift of the first two modes of vibration of the microstructure, which modes experience the phenomenon of veering (frequency...

This paper presents a tunable multi-threshold micro-electromechanical inertial switch with adjustable threshold capability. The demonstrated device combines the advantages of accelerometers in providing quantitative acceleration measurements and g-threshold switches in saving power when in the inactive state upon experiencing acceleration below the...

In this work, we explore the dynamics of inclined marine risers subjected to pulsating internal fluid flow. The presence of geometric nonlinearities with static deflection makes the response of the inclined riser different from conventional top tension risers when subjected to pulsating flows. At first, the riser model is solved via the Galerkin me...

We present a special electrode configuration for the selective actuation of the first three modes of a fabricated circular membrane resonator actuated by Lorentz force. The proposed electrode configuration is capable of exciting each sector of the membrane individually. Based on these features, the first three modes can be selectively activated or...

The present study investigates the experimental response of an electrically actuated microbeam-based MEMS resonator with arched configuration of concave surface. The resonator is excited using an antisymmetric partial electrode. Forward and backward frequency sweeps are acquired. The device exhibits M-shaped 2:1 internal resonance between the first...

The work discusses the nonlinear response of an inclined riser when it is subjected to pure pulsating internal flow. A numerical scheme is developed using Galerkin and validated using MTS perturbation method. Results showed the system experience nonlinear features such as quasi-periodicity and co-existence of solution which can be determinantal to...

Talk at NODYCON 2023

This work presents an analytical and experimental study to enhance the dynamic response of the higher-order vibration modes of resonant microstructures. The detection of higher order vibration modes is usually very difficult due to their low amplitude response, which gets buried in noise. Higher input voltages can be used to enhance the response; h...

In this article, we present a multithreshold microelectromechanical tunable inertial switch. The device aims to provide quantitative information on acceleration while retaining the attractive energy-saving features of binary threshold switches. The designed proof-of-concept device with three thresholds is composed of four serpentine springs, a susp...

This study presents a thorough theoretical and experimental investigation on the nonlinear damping of in-plane micromachined electromechanical resonators. More specifically, experiments are conducted on an electrically actuated bridge resonator, and the primary resonance response of the system is obtained at various AC and DC voltages. A nonlinear...

We present a highly sensitive multi-parameter sensor for magnetic and gas detection. The device is based on an in-plane doubly clamped micro-beam micro-resonator, which is electrothermally heated. It acts as a Lorentz force magnetic sensor of high sensitivity, good linearity, good repeatability, and low hysteresis effect. It also functions as a gas...

There is an urgent need to develop innovative and highly selective gas sensors for environmental, residential, and industrial applications. Here, we propose a highly selective multiple gases detection system using an electro-thermally heated silicon micro-resonator and machine learning algorithms. The device is based on the cooling/heating effect o...

We present a highly sensitive multi-parameter sensor for magnetic and gas detection. The device is based on an in-plane doubly clamped micro-beam micro-resonator, which is electrothermally heated. It acts as a Lorentz force magnetic sensor of high sensitivity, good linearity, good repeatability, and low hysteresis effect. It also functions as a gas...

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 en...

During the last decade, IR MEMS thermopile detectors have become a topic of increasing interest because of their reliable characteristics and excellent cost-performance ratio. Because of their many attractive characteristics, thermopile detectors have been frequently used in various IR detection applications. In this paper, we present an overview o...

We present a multi-mode excitation technique to significantly amplify the amplitude signal of micro-resonators-based sensors operating at their higher-order modes. We show that the multi-mode excitation can significantly reduce the noise effects, elevate the dynamic response level, and amplify the total amplitude response. We demonstrate the effici...

Demonstrate the numerical analysis of the stochastic dynamics of an inclined riser when it is subjected to random fluctuations in the internal fluid flow

In this work, we numerically explore the stochastic dynamics of inclined marine risers subjected to pulsating internal fluid flow. The presence of geometric nonlinearities with static deflection makes the response of the inclined riser different from conventional top tension risers when subjected to pulsating flows. At first, the riser model is sol...

Saturation is an intriguing phenomenon that has captured the attention of scientists since the time of Froude when he reported it for ship motion in the mid of the nineteenth century. This work presents the demonstration and a comprehensive study of the nonlinear saturation phenomenon on a compound micromachined structure of U-shape (micro portal f...

In this paper, we propose a single device for simultaneous measurement of in-plane magnetic field and gas concentration. The concept is based on tracking simultaneously the resonant frequency of the first two symmetric and anti-symmetric modes of an electrothermally actuated out-of-plane buckled micro-beam. First, the Lorentz-force magnetic sensing...

This paper presents a review of the recent advances on micromachined inertial switches/triggers. The review focuses on their advantages and disadvantages, sensitive directions, mechanisms of contact-enhancement, threshold accuracy, and the tunability of the acceleration threshold. Several applications of these sensors are highlighted including in h...

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 st...

In this work, we investigate analytically and experimentally parametric resonances of an in-plane clamped-guided shallow arch microresonator. The arch is connected to a T-shaped moveable mass, which is sandwiched between two electrodes to electrostatically activate the device and to offer bi-directional axial loads option. The device is tested unde...

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 shoo...

This work presents a nonparametric identification method applied to study the nonlinear response of an MEMS resonator. The MEMS resonator is a clamped-clamped microbeam fabricated for out-of-plane motion accounting for geometric nonlinearities due to midplane stretching while actuated by electrostatic forces. Experimental measurements show hardenin...

In this article, we present an inertial switch with three threshold levels, which can provide quantitative acceleration measurements and detect the acceleration direction in the x–y plane. The designed device has four movable electrodes attached to the proof mass (one at every side of the square proof mass) and 12 flexible stationary electrodes (...

This paper reviews the recent developments of micro-electromechanical system (MEMS) based electrostatically actuated tunable capacitors. MEMS based tunable capacitors (MBTCs) are important building blocks in advanced radio frequency communication systems and portable electronics. This is due to their excellent performance compared to solid state co...

This work presents a nonparametric identification method to study the nonlinear response of a micro-electromechanical system (MEMS) resonator. The MEMS resonator is a clamped–clamped microbeam fabricated for out-of-plane motion, which is dominated by the cubic nonlinearity due to mid-plane stretching while actuated by electrostatic forces. Experime...

We investigate experimentally and theoretically mode crossing and mode veering between the first two symmetric and anti-symmetric modes of an electrothermally and electrostatically actuated in-plane V-shaped micro-beam. The micro-beam is sandwiched between four electrodes to electrostatically activate both modes of vibrations and to offer various a...

We present a highly sensitive Lorentz-force magnetic micro-sensor capable of measuring low field values. The magnetometer consists of a silicon micro-beam sandwiched between two electrodes to electrostatically induce in-plane vibration and to detect the output current. The method is based on measuring the resonance frequency of the micro-beam aroun...

In this paper, an analytical model of a micro-electromechanical (MEM) resonator used as a 4-bit digital-to-analog converter (DAC) is presented. First, we derive the dynamic equation of the 4-bit DAC device, and the nonlinear governing equation is solved by the Galerkin method combined with a shooting technique to simulate the static response, linea...

We present a MEMS inertial switch with multiple, non-latching acceleration thresholds in two directions, that consumes no power in its inactive state. The design implements a suspended proof mass, with stationary electrodes placed at different positions in its sensitive direction so that different shock-induced displacements of the proof mass will...

In this paper, we investigate experimentally and theoretically the linear coupling between the first two symmetric and anti-symmetric modes of an electrothermally and electrostatically actuated in-plane V-shaped micro-beam. The micro-beam is fabricated from highly doped silicon and is sandwiched between four electrodes to electrostatically activate...

This paper presents a multi-threshold inertial switch demonstrated experimentally and through simulation. A laterally-driven multi-threshold inertial switch based on SOIMUMPs has been fabricated. The device has been tested by a drop-table test system under different shock accelerations with various amplitudes and pulse widths. In addition to experi...

In this work, we demonstrate a selective gas sensor based on monitoring two different detection mechanisms; absorption and thermal conductivity. To illustrate the concept, we utilize a resonator composed of a clamped-guided arch beam connected to flexural beams and a T-shaped moveable mass. The resonator has two distinct out-of-plane modes in which...

Micro/Nano-electromechanical systems, MEMS/NEMS-based resonators are presently an important part of a wide range of applications. However, many of these devices suffer from the low signal-to-noise ratio and the need for a large driving force. Different principles were proposed to enhance the sensitivity and improve their signal-to-noise ratios (SNR...

In this research, we investigate the structural behavior, including the snap-through and pull-in instabilities, of in-plane microelectromechanical COSINE-shaped and electrically actuated clamped-clamped micro-beams resonators. The work examines various electrostatic actuation patterns including uniform and non-uniform parallel-plates airgap arrange...

We present an investigation into the static and dynamic behaviors of electrostatically actuated in-plane micro-electro-mechanical V-shaped micro-beam under axial loads. The micro-beams are actuated with two separate electrodes of uniform air-gap across their length. The effects of the initial rise and DC bias voltage are examined while varying the...

This work presents detailed static and dynamic analysis of electrostatically actuated in-plane micro-electro-mechanical V-shaped micro-beam resonators. An analytical model is presented, based on the Euler Bernoulli beam theory, which accounts for the nonlinear electrostatic forces and the mid-plane stretching. The model is utilized to simulate the...

The cover illustrates a wideband mechanical energy harvester that utilizes street vibrations to power a traffic light. When this wideband harvester is placed in a vibrating environment, it converts the ambient vibrations into high‐voltage electrical energy. This energy can then be used to power various sensors and electronics. Further details can b...

We experimentally demonstrate a miniature highly sensitive wide-range resonant magnetic Lorentz-force micro-sensor. The concept is demonstrated based on the detection of the resonance frequency of an in-plane electrothermally heated straight resonator operated near the buckling point. The frequency shift is measured with optical sensing (laser) and...

Nowadays, there is increasing interest in fast, accurate, and highly sensitive smart gas sensors with excellent selectivity boosted by the high demand for environmental safety and healthcare applications. Significant research has been conducted to develop sensors based on novel highly sensitive and selective materials. Computational and experimenta...

We report a highly sensitive and miniature in-plane resonant Lorentz-force magnetic micro-sensor operating in air at atmospheric pressure. The concept is based on the detection of the resonance frequency shift of an electrothermally heated initially curved micro-beam experiencing the veering phenomenon (avoided crossing) between its first and third...

Many sensor applications require small and noninvasive methods of powering, such as marine animal tracking and implantable healthcare monitoring. In such cases, energy harvesting is a viable solution. Vibrational energy harvesting is abundantly available in the environment. These vibrations usually are low in frequency and amplitude. Conventional v...

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...

Describe the role of the non-linear geometry on the dynamics of inclined risers when they are subjected to vortex induced vibration loads. The numerical model is developed based on empirical formulation to capture lift forces and Morison to capture drag and inertia forces on the riser

We present a low power high sensitive in-plane resonant bidirectional Lorentz-force magnetic micro-sensor operating in air at ambient pressure. The concept is based on the detection of the resonance frequency shift of an electrothermally straight micro-beam resonator operated near the buckling point. Powered at 20 μW, the micro-sensor shows a measu...

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 experimental...

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...

This works aims to investigate the dynamics of Micro-electro-mechanical systems (MEMS) straight multi-stepped micro-beams. An analytical model is presented based on the Euler–Bernoulli beam theory and the Galerkin discretization. The effect of various parameters on the natural frequencies of micro-beams is examined, including the effects of varying...

We experimentally demonstrate a miniature highly sensitive wide-range resonant magnetic Lorentz-force micro-sensor. The concept is demonstrated based on the detection of the resonance frequency of an in-plane electrothermally heated straight resonator operated near the buckling point. The frequency shift is measured with optical sensing and the dev...

Beam electrothermal actuators amplify the thermal expansion of pre-shaped beams and use the symmetrical structure to create a linear motion. These actuators, including V and Z shapes, are widely used in microsystems. Explicit analytical expressions are derived in this paper governing the structural deformation of these actuators due to electrotherm...

We present a study of the natural (resonance) frequencies of a tunable in-plane Microelectromechanical portal frame (U-shape) under DC electrostatic loads. The structure is designed and fabricated to excite the in-plane anti-symmetric (sway, first) and the symmetric (second) modes. Experimental results show high tunability of the resonance frequenc...

This paper investigates the modeling, design, and task feasibility of V shape electrothermal actuators. In the first part, the force-deflection governing expressions are derived and the actuator performance is analyzed based on these expressions. The influence of the actuator dimensions and properties on its performance is clarified. In the second...

In this work, we study experimentally, analytically, and numerically the dynamics of electrothermally actuated micro-electro-mechanical V-shaped micro-beam resonators. Upon actuating the micro-beams electrothermally, we examine the various scenarios of natural frequencies crossing and avoided-crossing (veering) among the various vibration modes. Th...

In the era of IoT and smarter sensors and actuators, MEMS resonators are actively being explored for ultra-low-power computing devices due to their simplicity and potential toward energy-efficient computing machines. However, the realization of complex logic functions through the cascadability of MEMS resonator logic devices has introduced new chal...

Due to the increasing demand for smarter solutions and embedded systems, MEMS resonator-based computing devices have been under considerable attention for their simplicity and prospect of low computational power. However, most complex logic functions require multi-input/output lines that are cascadable such that the outputs of one device can be use...

We derive the snap-through solution and the governing snapping force equations for an arbitrarily pre-shaped beam deflected under a mid-length lateral point force. The exact solution is obtained based on the classical theory of elastic beams as a superposition of the initial shape and the modes of buckling. Two kinds of solution are identified depe...

The phenomenon of mode localization is explored theoretically and experimentally on two mechanically or electrostatically coupled beam resonators. Lumped parameter models are used to simulate the response of the systems. The eigenvalue problems are solved for both case studies under different stiffness perturbations and coupling strengths. The infl...

We present a novel design of a low-power micro-electro-mechanical digital to analog converter (DAC) based on a clamped-clamped micro-beam resonator with multiple split electrodes and capacitive airgaps of various widths. The proposed n-bit DAC device operates at a single drive frequency and can access one of 2^n distinct stable states based on the...

We present a spring-shaped tunable inductor, fabricated using a silicon-on-insulator (SOI) multiuser micro-electromechanical system process. The inductor has a simple planar design and is monolithically integrated in the SOI wafer. The inductor is tuned using a thermal actuator on the same silicon structure layer. Thus, the complexity and cost of f...

This paper presents for the first time implementation of zig–zag and solenoidal on-chip inductors in standard and cost effective SOI-MUMPs fabrication process. The solenoidal inductor offers high Q-factor and inductance as compared to planar zig–zag inductor. Bonding wires are used to construct the top conductor loop of the solenoidal inductor. The...

A bistable mechanism is proposed with symmetrical snap-through behavior between the two equilibrium positions. The mechanism is monolithic and does not require external axial load, as buckled beams. It consists of two pre-shaped beams of opposite curvature with similar properties and dimensions, which are connected after fabrication. The combinatio...

This study investigates the effect of air damping on in-plane silicon micro/nano-resonators sandwiched between two electrodes (two ports) for sensing and actuation. Experimental measurements are presented for the quality factor (Q) as varying pressure for several case studies of clamped–clamped and clamped–free micro/nano-beam resonators of various...

We study the multifrequency excitation of an inclined marine riser under two-to-one and three-to-one internal resonances. The riser model accounts for the initial static deflection, self-weight, and mid-plane stretching nonlinearity. By tuning the initial applied tension and configuration angles of the riser, the ratio between its first and third n...

We investigate in a silicon micromachined arch beam the activation of a one-to-one internal resonance between the first symmetric and first antisymmetric modes simultaneously with the activation of a two-to-one internal resonance between these modes and the second symmetric mode. The arch is excited electrically, using an antisymmetric partial elec...

We investigate, experimentally and theoretically, the linear mode coupling between the first symmetric and antisymmetric modes of an electrothermally tuned and electrostatically actuated micromachined arch resonator. The arch is excited using an antisymmetric partial electrode to activate both modes of vibrations. Theoretically, we explore the stat...

Mode localization is investigated in a weakly mechanically coupled system. The system comprises of two doubly-clamped microbeams mechanically linked with a coupling beam close to the anchors. The phenomenon is explored among the first three vibration modes pairs; each consisting of an in-phase and out-of-phase mode. A distributed-parameter model ac...

As transistors are reaching their fundamental limits in terms of power consumption, miniaturization, and heat generation, there is an imminent need to develop alternate computing technologies. One such an alternative is through micro/nanoelectromechanical systems (M/NEMS) that focuses on ultra-low energy consumption. Computing based on static MEMS...

The simplicity and prospect of energy efficiency of microelectromechanical systems (MEMS) resonator-based computing devices have captivated considerable research interest in recent years. Hence, they are being explored for ultra-low power computing machines, which are currently needed for internet-of-things (IoT) applications. Recently, there have...

We report a new gas sensing technique based on the simultaneous tracking of multiple modes of vibration of an electrothermally heated bridge resonator operated near the buckling point. The proposed technique maximizes the sensitivity of the sensor to changes in gases concentrations. We demonstrate a 200% frequency shift in contrast to 0.5% resistan...

We report a highly sensitive wide-range resonant pressure sensor. The concept is based on tracking multiple modes of vibration of an electrothermally heated initially curved micro-beam experiencing the veering phenomenon between its first and third vibration modes. For low values of pressure, the third resonance frequency is very sensitive, and thu...

Micro and nanoelectromechanical systems M/NEMS have been extensively investigated and exploited in the past few decades for various applications and for probing fundamental physical phenomena. Understanding the linear and nonlinear dynamical behaviors of the movable structures in these systems is crucial for their successful implementation in vario...

Miniaturized air-pressure sensing devices has received increasing attention during the past few decades. Pressure sensors have been explored in various potential applications, such as industrial control, healthcare, medical testing, and environmental monitoring [1–2]. Different sensing mechanisms and designs have been used for the detection of air-...

The quest for ultra-sensitive low-cost miniaturized gas sensors in the past few decades has sparked interest to seek alternative approaches other than the conventional gas sensors that need large surface areas and special chemicals for functionalization. MEMS thermal conductivity based gas sensors [1, 2] have been shown to be among the promising ca...

We present an investigation of the dynamic behavior of an electrostatically actuated resonant structure, resonator, under the simultaneous excitation of primary and subharmonic resonances. A comprehensive analytical solution is obtained via the method of Multiple Time Scales (MTS), which is applicable for generic electrostatic loading cases. Result...

Conventional pressure sensors rely on diaphragms with large surface areas, which deform in response to pressure. Down scalability of these devices is one of the major challenges of the technology along with reducing the overall actuation voltage and achieving ultra-high sensitivity. We present a sensitive miniature pressure sensor based on the chan...

In this work, the design principles and experimental demonstration of a compact full adder along with a reprogrammable 4 input logic gate are presented. The proposed solution for implementation of digital circuits is based on a clamped-clamped micro-beam resonator with multiple split electrodes, in which the logic inputs tune the resonance frequenc...

We investigate modeling the dynamics of an electrostatically actuated resonator using the perturbation method of multiple time scales (MTS). First, we discuss two approaches to treat the nonlinear parallel-plate electrostatic force in the equation of motion and their impact on the application of MTS: expanding the force in Taylor series and multipl...

We present an investigation of the dynamic behavior of an electrostatically actuated clamped–clamped microbeam, under the simultaneous excitation of primary and subharmonic resonance. The simultaneous excitation of primary and subharmonic resonances of similar strength is experimentally investigated by using different combinations of AC and DC volt...

We demonstrate a simple and flexible technique to efficiently activate micro/nano-electromechanical systems (MEMS/NEMS) resonators at their fundamental and higher order vibration modes. The method is based on the utilization of the amplified voltage across an inductor, L, of an LC tank resonant circuit to actuate the MEMS/NEMS resonator. By matchin...

The present chapter highlights the importance of the dynamical integrity theory for micro and nanoapplications. Three case-studies of devices at different scales are presented (a capacitive accelerometer, a microbeam-based micro-electro-mechanical system, and a single-walled slacked carbon nanotube) and different issues commonly addressed in the en...