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Surface plasmonic sensors have gained significant attention for their exceptional sensitivity and detection capabilities. However, the cost and fabrication complexity are crucial factors influencing the practical applicability of these sensors. In this study, a specific kind of plasmonic sensor benefiting from the advantages of tunable optical grating coupling zone has been subjected to the development in terms of cost and fabrication procedure. This progress involves the structuring of the coupling region on the glass-based substrate leveraging the straightforward micromachining techniques. The proposed coupling layout features a periodic pattern comprising the glass-based substrate sequentially deposited with Cr and Ni using the lift-off technique. This setup operates based on The Kerr electro-optic effect facilitating the precise delivery of stimulating light onto the surface plasmons (SPs) while bringing a small footprint for the sensor. The performance of this configuration has been assessed and optimized using the finite element method (FEM), and its results were reported in the following to declare a robust performance of this structure while enjoying the advantage of low-cost and simplified fabrication process. [ABSTRACT FROM AUTHOR]

In this article, a rectangular coil in the form of a flexible printed circuit board (F-PCB) with FR4 substrate is designed and fabricated. Owing to its flexibility, the coil can be curved which facilities its use in nuclear magnetic resonance (NMR) spectroscopy. Two samples of this F-PCB coil are faced each other in place, aiming to achieve a range with a uniform magnetic field in the middle of the coils. The performance of the proposed structure is compared with a planar PCB structure. Although the developed coil is intended for NMR spectroscopy, it can also be used in other applications such as wireless power transfer. As a special application, the proposed coil can be adopted in a portable NMR spectroscopy device for analysis and identification of metal minerals. Advantaged from reduced weight and occupied volume, precise design, flexibility and increased efficiency, the presented F-PCB coil can be considered as a promising alternative to the conventional coil. The finite element method (FEM) simulations are performed using COMSOL Multiphysics software and the results have been analyzed in the frequency domain. The results show that the proposed coil has 92% uniformity of the magnetic field in wide frequency range of 3–6 MHz that is used in NMR. The experimental results obtained from the fabrication device under test are compared with simulation results. The measured magnetic field in the sample area is 102 µT. [ABSTRACT FROM AUTHOR]

Surface plasmon resonance-based sensors are one of the most accurate detectors of chemical and biochemical components in microfluidic structures performed based on changes in the refractive index of the medium adjacent to the sensor surface. In such sensors, the performance is strongly influenced by the amount of light coupled with surface plasmons. Consequently, the electromagnetic waves should reach the metal layer much more accurately. Precise adjustment of the excitation angle and occupation volume of one kinds of such sensors are among their highlighted challenges that come from conventional light coupling technique. In this paper, a novel idea for designing this type of sensor in microsystem technology is devised, which is capable not only of adjusting angle of optical excitation using thermal-optical effect, but also of occupying the least amount of space. This design is optimized and validated using Finite Element Method, so that the sensor performance in exchange for changes in parameters such as refractive index and metal thickness is examined and displayed in the form of tables and graphs. Simulation results reveal that the proposed model is able to tune optical excitation angle such accurate that the SPR phenomenon occurs at an angle of 21.21° at the outer boundary of 42 nm thick of gold layer at its best. [ABSTRACT FROM AUTHOR]

In this paper, a MEMS-based biosensor composed of coupled microresonators is proposed for digital microfluidics applications. This sensor consists of three parts including electrostatic comb-drive actuators, capacitive sensing, and active area located in the center of the structure. All applied resonators are in the same sizes which are connected with springs. The active area vibrates azimuthally utilizing in-phase electrostatic actuators on three sides. The manipulated droplet, encapsulating bio-particles, is driven to the immobilized active zone and makes the vibration frequency change. Due to in-plane vibration of the proposed structure, the viscous damping has less effect on the quality factor of the sensor. The total system is simulated by finite element methods and the results demonstrate that the desired vibration frequency for in-plane motion of the sensor is 18.37 kHz and the quality factor and mass sensitivity are 58 and 78 Hz/µg, respectively, which is comparable to sensors with similar applications. [ABSTRACT FROM AUTHOR]

A two-dimensional phononic crystals based hypersonic-wave switch is theoretically investigated. The temperature effect is considered for a two-dimensional solid–solid phononic crystal composed of a square array of Epoxy rods embedded in a Tungsten matrix. Using finite element method, temperature dependence of the band gap is examined. The numerical results show that the bandgap position and width strongly depend on the temperature and they can be modified when the temperature increases from 10 to 45 °C. Due to its good contrast with Tungsten and Epoxy in elastic properties and its high temperature dependence, Barium Strontium Titanate [Ba0.7Sr0.3TiO3] (BST) is used as the defect material. Defect modes could be tuned by modifying the radius of BST filled rods. The strong temperature dependence and phononic crystals periodicity prove the structure desirable for thermal switching. A hypersonic-wave 1 × 3 switch is designed for the specific frequency f = 1.50 GHz at room temperature. [ABSTRACT FROM AUTHOR]

liquid marbles are liquid droplets that encapsulated with hydrophobic micro-nano sized particles. These liquid soft solids, as a promising digital microfluidic systems, offer a simple alternative to conventional discrete microfluidic systems and may have wide applications in biomedical, biochemistry and nanotechnology. In this experimental and numerical study, first, for production of magnetic liquid marbles, Fe3O4 magnetic nanoparticles were synthesized and hydrophobized with paraffin wax. Second, by slight rolling of water droplet on Fe3O4@Isoleucine-P wax nanoparticles, the formation of our magnetic liquid marble is achieved. Third by modeling our liquid marble by a droplet with an elastic shell, the effect of gravity on marble shape simulated and verified with experimental results. The results obtained from the simulation analysis fit well to the experimental data describing the shape of liquid marble under the force of gravity. [ABSTRACT FROM AUTHOR]

A novel H-plane loaded on a double-staggered grating waveguide (DSGW) slow-wave structure (SWS) is proposed. The main advantage of this SWS is its high interaction impedance and low phase velocity, based on which higher output power can be expected. Electromagnetic characteristics and particle-in-cell simulations were performed using CST Microwave Studio software. The dispersion diagram of the SWS was optimized for a central frequency of 94 GHz which corresponds to a beam voltage of 13.2 kV in the second spatial harmonic (2 π –3 π ). A sheet electron beam with a current of 200 mA is used to interact with the longitudinal electric field. The reflection signal at the input port is below −15 dB for frequencies of 89–98 GHz and a small-signal gain of 35 dB is achieved at the output port for a tube length of 80 mm. [ABSTRACT FROM AUTHOR]

The design and simulation of a continuously tunable LC filter by integration of microelectromechanical systems (MEMS) is presented in this work. The proposed tunable LC filter consists of a tunable capacitor and four inductors. The novelties of this RF-MEMS circuit include the integration of both mechanical suspensions with electrical inductors and the electrostatic actuator with the electrical capacitor. This filter is designed based on standard MetalMUMPs fabrication process trademark of MEMSCAP. With this filter, the frequency range from 2.5 to 3 GHz is achieved in the UHF band. High-quality performance is determined based on the 3 dB-bandwidth with about 83 MHz. The insertion loss of − 2.8 dB and the return loss of − 17.58 dB up to − 21.43 dB are other bold characteristic points of this design. The power consumption is near-zero thanks to the use of the electrostatic actuator. Therefore this filter can be used in low power and high-performance RF tuning applications. The group delay of this filter is less than 2.5 ns and the quality factor is from 45 to 85. [ABSTRACT FROM AUTHOR]

In this paper a sensor based on MEMS resonators is proposed for digital microfluidics applications. The sensor system consists of a disk as active area immobilized for capturing any special particles. This disk can azimuthally vibrate by means of two in phase electrostatic actuators both sides. Two capacitive sensing elements determine the vibrating amplitude. The moving droplets by digital microfluidic module will envelope the disk of active zone, so the captured particles can change the vibration frequency of resonance. Due to azimuthal vibration, the fluidic damping is low enough to achieve measurable quality factor by resonator. The total system is simulated and the result is presented. [ABSTRACT FROM AUTHOR]

In this article, a novel planar helix traveling wave tube structure is proposed for S/X-band amplification. The planar helix structure is developed between two printed circuit boards such that they utilize solder balls to connect each other. This technique which comes originally from microelecronic packaging technology called ball grid array. To evaluate the performance of the proposed structure, one period of its geometry is modeled and the cold test parameters are calculated in CST microwave studioTM. The fundamental space harmonic mode overlaps well with the beam-line in the dispersion diagram for both bands. The in- and out-coupler ports are also designed in the form of coplanar waveguides having good matching. For 150 periods of the planar helix, the 15 dB gain is obtained in particle-in-cell simulations for both bands. Finally, the fabrication process is implemented and the cold test is done. [ABSTRACT FROM AUTHOR]

A combination study of magnetic and magnetostrictive properties in directionally cast (DC) (un-annealed) and differently heat-treated Fe–19 at% Ga samples was carried out at room temperature. Slow cooling leads to an increase in the occupation of [2 0 0] easy magnetic axis. However, structural ordering of Ga atoms into a metastable D03 phase decreases the saturation magnetostriction (λs) and saturation magnetization (Ms), while increases coercivity (Hc). Water quenching suppresses the formation of stable fcc ordered phase (L12) and largely preserves disordered bcc single-phase (A2) structure down to room temperature, leading to enhanced magnetostriction and magnetization. Slow cooling promotes the ordering of metastable bcc ordered phase (D03). Magnetic force microscopy (MFM) study exhibits that the water-quenched (WQ) sample consists of a well-aligned stripe domain structure, while irregular maze-like domain structure is observed in furnace-cooled (FC) sample. The results confirm that in addition to an inhibitory effect of D03 ordering on magnetic domain wall motions, irregular magnetic domains also contribute to decrease in magnetic and magnetostrictive properties of FC sample. [ABSTRACT FROM AUTHOR]

In this paper, we present a four-channel wavelength division demultiplexer which is designed by means of cascading three 1×2 multimode interference couplers. The proposed structure separates 980, 1310, 1490, and 1550 nm wavelengths into the appropriate ports. These wavelengths have been chosen for separation due to their importance in the optical communication systems. The performance of proposed demultiplexer has been optimized by choosing a suitable refractive index of the guiding region and geometrical parameters such as the width and length of coupler. Therefore, the total size of the demultiplexer is significantly reduced. Beam propagation method has been utilized in order to design and optimize the operation of the introduced structure. Simulation results indicate that the insertion losses of 980, 1310, 1490, and 1550 nm wavelengths are 0.52, 1.54, 0.64, and 1.4 dB, respectively. [ABSTRACT FROM AUTHOR]

This paper introduces a novel method for designing of low actuation voltage, high tuning ratio electrostatic parallel plate RF MEMS variable capacitors. It is feasible to achieve ultra-high tuning ratios way beyond 1.5:1 barrier, imposed by pull-in effect, by the proposed method. The proposed method is based on spring strengthening of the structure just before the unstable region. Spring strengthening could be realized by embedding some dimples on the spring arms with the precise height. These dimples shorten the spring length when achieved to the substrate. By the proposed method, as high tuning ratios as 7.5:1 is attainable by only considering four dimple sets. The required actuation voltage for this high tuning ratio is 14.33 V which is simply achievable on-chip by charge pump circuits. Brownian noise effect is also discussed and mechanical natural frequency of the structure is calculated. [ABSTRACT FROM AUTHOR]

The ability to control and manipulate the high ionic strength fluids is major advantage for fluidic on-chip biological analysis. In this study we proposed an AC electrothermally-driven configurable flow for forward/reverse pumping and also clockwise/anti-clockwise rotational effects. Electrode discretization allow us to generate such a configurable AC electrothermal effects by simple switching the electric potential over the various asymmetric electrodes. Taguchi optimization method have been applied for discretized electrode dimensions and pumping/rotational effects was numerically studied by solving the coupled multi-physic fluidic, convection-diffusion, thermal and electric field equations. High efficient mixing process (above 90 %) achieved by exciting the electrodes in time-varying clockwise and anti-clockwise rotational mode. Thereafter, three particles released inside the channel and the particles were stretched, folded and finally separated by exciting the electrodes in rotational mode (a proof of chaotic regime). We investigate the proposed ACET characteristic, the results confirmed that the proposed system is efficient for high conductive mediums and the efficiency increase by increasing the non-uniform electric field intensity. Based on the frequency analysis from 100 to 500 MHz, the working frequency range of the configurable system is increases by increasing the electric conductivity of solution. [ABSTRACT FROM AUTHOR]

In this work a novel electrode structure is proposed to separate viable and non-viable yeast cells by travelling-wave dielectrophoresis (twDEP). The electrodes are chevron-shaped which the sharp angle at the center of the electrodes is replaced by a curvature. We employed finite element method to simulate and observe the electric fields related to conventional dielectrophoresis (cDEP) and twDEP and correspondingly to estimate the cell trajectories under the applied electric field. Furthermore, we discuss different physical and geometrical parameters to design our twDEP microseparator to get the most accurate operation and higher separation efficiency. First, we study the adequate frequency and medium conductivity. Then, we explore the optimized electrode dimensions for target cells. From the simulations, we discovered that by the proposed electrode structure and applying phase shifted AC electric potential with amplitude of 2 V and frequency of 70 kHz viable yeast cells discriminate from non-viable ones and get focused on a band at the center of the channel, simultaneously. The simulation results reveal that here the maximum twDEP force is applied to yeast cells when electrode width is about 12 μm. Finally, we propose possible different electrode forms that can be derived from our proposed electrode shape to manipulate different cells/particles. [ABSTRACT FROM AUTHOR]

In this paper, we present a novel laterally actuated DC-contact three-state RF MEMS switch. Rotary electrostatic comb-drive actuators which can be rotated both clockwise and anti-clockwise are chosen as the drive mechanism of the switch and are integrated inside of the switch, hence the switch has a very compact structure. The proposed switch is designed in such a way that it can be used in antenna switch applications where having high isolation and low insertion loss are of most important operating characteristics. The switch has three operating states of ON, OFF and deep-OFF. Different FEM simulations are carried out in order to optimize RF and mechanical behavior of the switch. The switch has acceptable RF performance in a frequency range from DC up to 40 GHz with near to zero power consumption. The actuation voltage of the switch is 50 V. The switching time from OFF to ON state or deep-OFF state is 79 µs and return time to OFF state is 130 µs. The switch has an insertion loss less than −0.87 dB up to 40 GHz, and return loss below −21 dB at the same frequency range. The OFF state and deep-OFF state isolations are −35 and −60 dB up to 40 GHz, respectively. [ABSTRACT FROM AUTHOR]

A new electro-thermally driven high Q tunable RF MEMS capacitor is proposed in this paper. The tuning mechanism of the varactor is chosen to obtain tuning; hence the capacitor has linear tuning range. In order to satisfy the low voltage operation of the varactor electro-thermal actuators were chosen as the drive and latching mechanism. However, those actuators consume lots of power, accordingly, in order to suppress that shortcoming a true mechanically latching mechanism is proposed which considerably decreases the total power consumption of the varactor. In order to investigate important operational aspects of the proposed varactor, different FEM simulations are carried out. The results are as follow; the Q-factor is 43.39 at 1 GHz for a 0.46 pF capacitance value. The tuning ratio is 1.17:1 and self-resonant frequency is 16.61 GHz. The propose varactor works by applying an actuation voltage of 3.1 V and consumes a power of 180 mW for about 2.7 ms for each tuning steps. The proposed varavtor of this paper can be a promising choice for low lass and low power RF tunable networks. [ABSTRACT FROM AUTHOR]

Any mechanically suspended structure is subject to unwelcomed environmentally induced mechanical vibrations. The designer needs to use a design strategy in order to those interferences don't disturb the normal operation of the structure by producing undesirable outputs. This paper proposes a new method for enhancing mechanical resonant frequencies of MEMS-based frequency reconfigurable microstrip patch antenna. The objective of enhancing mechanical resonant frequencies is to make the antenna structure resistant against environmentally induced mechanical disturbances. The novelty of this design is in creating embedded slots on antenna patch and membrane for decreasing the mass of the suspended part of the antenna. The mass reduction achieved in the proposed antenna can be viewed from two perspectives; (1) by etching out embedded slots on patch and membrane the mass of the suspended structure decreases (2) creating embedded slots on antenna patch considerably decreases the operating frequency, hence it is not need to increase patch dimensions in order to operate in low operating frequencies. In order to show the effectiveness of proposed method, four antennas with operating frequencies of 15, 10, 5 and 1 GHz are designed. The first mechanical resonant frequency of the antennas designed by proposed method are 1,234, 959, 521 and 97 Hz, respectively. However, the antennas designed by conventional method have the first mechanical resonant frequency of 620, 306, 100 and 2 Hz. Comparing these results, it can be obviously seen that by the use of proposed method the mechanical resonant frequency of the antenna is considerably enhanced. [ABSTRACT FROM AUTHOR]

A new lateral electro-thermally actuated latching RF MEMS switch is presented in this paper. In contrast to conventional electrostatic or electro-thermal MEMS switches which require an actuation voltage to hold the switch in on or off state, this switch has a true mechanical latching design in such a way that there is no power required to hold the switch on or off. The switch structure only consumes power while transition between states. In order to satisfy low voltage operation, electro-thermal actuators are chose as the drive and latching actuators of the switch. The required actuation voltage for drive and latching actuators is 6 V. The switch consumes a power of <99 mW while transition from off to on state and also consumes a power of 46 mW for 0.3 ms in transition from off to on states. FEM simulations show that the return loss of the switch is below −10 dB up to 140 GHz and is below −20 dB up to 40 GHz. The insertion loss of the switch is less than −1 dB up to 150 GHz. The switch isolation when it is off is below −20 dB up to 160 GHz. The switch has potential applications in low voltage, low power and high performance RF tuning and switching applications. [ABSTRACT FROM AUTHOR]

Future markets demand high performance inertial sensors implemented by incorporating a micromachined sensing element in a closed loop controller. There is a nonlinear effect on electrostatic control force for closed loop sensors. Nonlinear control force degrades the closed loop controller performance. This study reports a controllable microgyroscope design concept with the help of a new 2-degrees-of-freedom (2-DOF) sense mode oscillator to linearize the electrostatic control force. However, design of a structure with characteristics including high mechanical gain and high operational frequency without sacrificing electronic sensitivity is serious challenge for 2-DOF dynamical systems. The proposed design can involve these parameters simultaneously in addition to control force linearity. Besides, greater electronic sensitivity is achievable due to ability of selecting secondary mass (sense mass) larger than primary mass. The prototype with an overall size of 0.46 × 0.635 mm is designed to be fabricated in surface micromachining process with 3 μm structural layer thickness. In addition to providing finite element method (FEM) simulation results, the conventional and proposed 2-DOF design performances are compared using MATLAB analysis. [ABSTRACT FROM AUTHOR]

This paper presents design and simulation of a novel electrostatic microelectromechanical systems gripper with an integrated capacitive contact sensor. Moreover, this microgripper is able to employ vibration to release micro objects (cells) actively. Lateral comb drive system is used to close the gap between the gripper arms and hold the objects while the transverse comb differential capacitances act as a contact sensor to prevent damaging the fragile micron-sized particles specifically biological cells. In addition, the capability of the microgripper in generating vibration at the end-effectors electrostatically is an advantage to facilitate releasing process by overbalancing the adhesion forces between the particle and the gripper arm. Finite element analysis based simulations are carried out to estimate the behavior of the microgripper while the standard SOI-MUMPs micromachining process is proposed for fabrication of the microgripper. [ABSTRACT FROM AUTHOR]

Microelectromechanical systems are utilized alongside with transistor amplifiers and resistive connections for implementing of oscillatory associative memories. Phase locking is studied in such a network and all requirements of the circuit level implementation are satisfied. A very high gain trans-impedance amplifier operating in 1 GHz in addition to a novel automatic amplitude control circuit is employed to remove amplitude dynamics of the system. Requiring resonator characteristics are extracted and calculated as well. A new method for initialization of the network is proposed. Each neuron consumes 1.08 mW from a 1.8 V power supply. The convergence time of a typical network trained by Hebbian rule is less than 1.5 ns which results in an ultra high speed analog signal processing system. [ABSTRACT FROM AUTHOR]

This study investigates the magnetostrictive functionality of crystallographic textures developed by directional solidification of a vacuum-melted galfenol cast button. A polycrystalline FeGa alloy was melted using vacuum arc melting and solidified in a water-cooled copper mold. Optical metallography confirmed the development of large columnar grains in the solidification microstructure. Phase constitution and magnetic domain structures of sample were studied by X-ray diffraction (XRD) and magnetic force microscopy (MFM). The results showed that the cast button has a disordered body-centered cubic (bcc) (A2) single-phase structure that consisted of a combination of well-aligned stripe-like and maze-like magnetic domains. To investigate the magnetostriction behavior, a couple of pins were cut along columnar grains as well as in the transverse direction. Magnetostriction was measured in the presence of an externally applied magnetic field. It was found that pins cut along the columnar grains comprised very high magnetostriction, whereas transverse pins had lower magnetostriction against the applied field. [ABSTRACT FROM AUTHOR]

In this study, we investigate a novel metallic microgripper which is able to grasp and transport nano particles (nano tubes/wires) and release them on desirable substrate by vibrating the gripper arms. This microgripper consists of a chevron actuator to grip nano object electrothermally and interdigited comb drive systems to generate vibration at the gripper arms electrostatically. Metallic (nickel) properties enable the chevron actuator to close the gap and pick the nano particle at low voltage and temperature. In order to reduce the out of plane bending during operation and also increase the gripping force, thickness of the nickel layer must be increased, hence electroplating process is proposed for deposition of nickel layer. To generate vibration at the end effectors, comb drive systems are stimulated by applying two voltage signals at desired resonant frequency to the stators. Practically, by sweeping the frequency of these signals around the resonant frequency the end effectors start vibrating. The vibration results in overcoming the adhesion forces due to inertial effects. [ABSTRACT FROM AUTHOR]

In this paper, a novel model of a frequency reconfigurable microstrip patch antenna based on MEMS (microelectromechanical system) technology is introduced. Fabrication process of the proposed antenna is comprised of bulk and surface micromachining. Patch of the antenna is deposited over a silicon platform. The platform is created by structuring the silicon membrane which is formed through bulk micromachining of a silicon chip. The patch and the platform beneath it are discretized to facilitate their vertical displacement over underside air gap. Thermal actuation is used as driving mechanism. Operational mechanism of the antenna is such that by downward relocation of the patch, its resonant frequency shifts downward. Thermal actuators are connected to the platform and applying voltage to them cause downward shift in resonant frequency of the antenna. FEM (finite element method) simulations confirm mechanical and microwave performances of the antenna which are investigated by theoretical analyses. From mechanical point of view, antenna has tolerable mechanical stability and microwave point of view indicates that return losses are good (below $$-$$10 dB) and radiation patterns are very close to each other with reasonable gains. Moreover VSWR is less than 2 throughout the frequency tuning range. In the proposed antenna by applying a CMOS compatible voltage in the range of 0-4.5 V to each thermal actuator, the resonant frequency of the antenna shifts from 17.37 GHz in up-sate position to 15.07 GHz in down-state position. As a result of this frequency shift, a frequency tuning range of 2.3 GHz with bandwidths of 3.9 % in up-state and 1.4 % in down-state positions is achieved. [ABSTRACT FROM AUTHOR]

This paper presents an analytical evaluation of the previously demonstrated Ring Shape Anchored Contour Mode Disk (RSACMD) resonator and extracts its equivalent electrical circuit. In the next step, a series resonant Pierce oscillator is designed and parameterized based on the calculated MEMS characteristics. Due to the inherent 180° of phase shift in the RSACMD resonator equivalent circuit, a modified version of a Pierce sustaining circuit is introduced with two inverters (instead of one inverter in conventional Pierce oscillators) to compensate that extra phase shift and satisfy Barkhausen criteria. The designed circuit presents excellent phase noise performance because of a special design which results in small frequency pulling and enable the circuit oscillate close to natural frequency of the high Q resonator. The overall circuit consumes less than 257 μW from a 1.8 V power supply. [ABSTRACT FROM AUTHOR]

In order to offer the ability of smaller volumes and high throughput in Lab-On-a-Chip and micro Total Analysis Systems devices, more miniaturized components are needed. Due to a low Reynolds number on the microscale, the mixing process can be particularly troublesome. This problem is compounded by the fact that more miniaturization can be challenging in a microfluidic system. In such a case, electroosmotic (EO) force is an efficient force to perturb low Reynolds number fluid. In this paper, a novel Micro-Electro-Mechanical-Systems (MEMS) based fabrication for microfluidic devices, and a more miniaturized micromixer are presented. The proposed technology process requires the covering of excited electrode patterns by a thin Silicon-Nitride (SiN) insulator layer. Fabrication parameters such as Low Pressure Chemical Vapor Deposition (LPCVD) SiN deposition effect, and height of the Phosphor Silicate Glass (PSG) sacrificial layer were investigated for the electroosmotically-driven mixer. Particle tracing for fluid flow was illustrated, the particles were stretched and folded for a long time, which was a proof of chaotic regime. Finite Element Analysis (FEA) revealed that the mixer with covered electrodes provides the high mixing efficiency of above 90% for a 96 μm long microchannel. Using a silicon nitride insulator layer reduces high electric field gradient at sharp corners and edges of the electrodes, leading to the elimination of unwanted electrolyte effects. Thus, the excitation and geometrical parameters were optimized for the micro mixer. [ABSTRACT FROM AUTHOR]

The design of RF MEMS filters is a very important research area in the RF MEMS resonator field especially for UHF frequencies. Having very high Q and compatibility with the state-of-the-art CMOS technology, RF MEMS resonators could construct channel select filters in RF transceivers front-end and surmount the need for IF stages by direct conversion. But, there is a problem for coupling of high stiff contour mode disk resonators, because there is no nodal region at the perimeter of this kind of resonators for establishing the low velocity coupling without applying asymmetry on the resonance performance of the resonators. This paper introduces a pioneering technique for low velocity coupling of these resonators without any asymmetry. Analytical design approach and FEM analysis are provided in this paper and our discussions are verified by various simulations. The resulting filter could be designed to obtain 0.004 % of bandwidth with reasonable sizes which is completely enough for channel selection in low GSM standard. [ABSTRACT FROM AUTHOR]

One of the most encumbering issues in RF MEMS resonators is spurious modes. The problem of spurious modes becomes more critical, when the ring type resonators are used. In the ring shape anchored contour mode disk resonator, for achieving a low serial resistance, the inner radius of the disk must be increased. This causes the spurious modes to become too close to the desired mode and degrade the operation of the resonator. In this work, spurious modes of before-mentioned device are introduced and their characteristics are evaluated by exact analytical approach. Based on those analytical approaches, we introduce two techniques for spurious mode suppression. The first technique is based on exciting the desired mode by proper electrode engineering and hence is an electrical approach. The second technique is reconfiguring of the anchor from a continuous ring to crossed ring segments and locating the segments on the phase discriminating lines to increase the insertion loss for spurious modes and decrease the losses for the fundamental mode. The final harmonic analysis verifies that the proposed techniques result a resonator with a pure frequency spectrum and spurious modes excluded over a very wide frequency range. [ABSTRACT FROM AUTHOR]

new high reliable microelectromechanical radial contour mode disk resonator is demonstrated with the ability to work at UHF range and high quality factor in both vacuum and air. This structure is capable to work at second radial mode without increasing the insertion loss and therefore lowering Q. These characteristics are achieved because of the ring shape anchor which is placed at the nodal ring of a hollow disk resonator at the equivalent second radial mode. Also the ring shape anchor seems to be more reliable than stem shape anchors reported in previous works. The motional resistance of the resonator is decreased due to displacement of electrodes, both inside and outside of the structure. In addition to providing simulation results, this paper formulates the resonance frequency and calculates the optimum location of the anchor. Transfer function, resonance frequency and anchor displacement versus inner radius are also studied. [ABSTRACT FROM AUTHOR]

Mechanical resonators are rarely reported to be used in liquid environment due to high damping. Most applications of mechanical resonators are related to their use in the gaseous environment. In this paper, a novel mass detective biosensor is proposed for Lab-On-a-Chip applications based on micromechanical resonator array. The sensor can be fabricated by MEMS technology such as standard Polysilicon Multi User MEMS Process (PolyMUMPs). The sensor consists of chained mechanically coupled resonators with electrostatic actuating elements and capacitive sensing elements on both sides. The sensor is suitable for digital microfluidic applications which an under test droplet can be led over the resonator array and affect the frequency or the phase delay of vibration. Thus, both sides of the array containing the actuating and sensing elements stay away from the droplet. It provides conditions that do not electrically interfere with the sample droplet. The vibration direction of resonators under liquid droplet is such that causes light slide film damping and does not cause strong squeeze film damping. The commercial finite element tool COMSOL Multiphysics is used to analyze the vibration behavior of proposed sensor and verify its functionality. The results are presented for the frequency response and mass sensitivity of the biosensor. [ABSTRACT FROM AUTHOR]