1,720,997 research outputs found
Aspects of Mechanical Reliability for RF-MEMS Switches with Self-Recovery Mechanism to Counteract Stiction
No full textIn this work we discuss the operation of an active self-recovery mechanism, embedded within MEMS (MicroElectroMechanical Systems) switches for Radio Frequency (RF) applications, able to counteract the stiction induced by charge accumulation [1] and micro-welding formation [2]. Such a mechanism, based on the thermo-electric effect, allows for restoring the MEMS switch back to normal operation after a failure. This is done by means of two factors, namely, the entrapped charges dispersion speed-up [3] within the insulating layer between the electrodes, and the application of shear forces on the welding points, both induced by the heat. Preliminary experimental results, collected by a few fabricated MEMS switch samples, confirm the viability of the proposed approach
A reconfigurable impedance matching network entirely manufactured in RF-MEMS technology
No full textIn this work we present a reconfigurable impedance matching network for RF (Radio Frequency) applications, entirely manufactured in MEMS technology (RF-MEMS). The network features four impedance sections. The way they load the RF line (i.e. in series or shunt configuration) as well as the type of impedance they realize (purely capacitive, inductive, or both in parallel) are reconfigured by means of RF-MEMS cantilever-type ohmic switches. A few specimen of the network have been fabricated using the RF-MEMS technology platform available at FBK and experimentally characterized. In particular, the electromechanical characteristic of the RF-MEMS switches is observed, and the upward bending of the switches contact tips made the characterization of the RF behavior impossible. The non-planarity is due to the accumulation of residual stress within the suspended Gold layer during the release of suspended structures, and is currently being mitigated by performing a low-temperature release step. Electromagnetic simulations (S-parameters) of the RF-MEMS network are also reported in this paper, showing the wide range of impedance transformations enabled by such a complex device based on MEMS technology
Automatisiert erstelltes und experimentell verifiziertes Mixed-Level-Modell fuer einen mikromechanischen HF-Schalter
No full textWir demonstrieren die Ableitung, Kalibrierung und experimentelle Verifikation eines energiebereichs�bergreifenden Makromodells f�r einen mikromechanischen Hochfrequenzschalter nach einem streng hierarchischen Modellierungskonzept. Die Modellgenerierung erfolgt automatisiert mit Hilfe einer Toolbox in MATLAB. Die einzelnen Teilmodelle sind physikalisch basiert und somit transparent. Sie werden systematisch anhand von Messungen kalibriert, bevor sie zu einem Gesamtmodell in Kirchhoffscher Formulierung vereint werden. Das erstellte, pr�diktive Modell ist in der Lage, die sich �ber die Auslenkung beim Schalten nichtlinear ver�ndernde D�mpfung auf den Schalter korrekt zu beschreiben und liefert eine gute �bereinstimmung mit den optischen Messungen
Validation of a Multi-Energy Domain Coupled Macromodel for Viscously Damped MEMS at Varying Pressure Conditions
No full textMicroelectromechanical (MEM) acceleration sensors are packaged at specifically chosen pressure levels in order to generate a defined viscous damping force on the moving microstructures. This specially designed damping force is crucial for the correct operation of the device [1]. To calculate the pressure levels that correspond to the desired damping force and to evaluate the sensitivity w.r.t. pressure changes, e.g. due to package leakage, the designers need models that allow for the predictive and fast transient simulation of the full MEM device. Since MEM device design involves multiple physical energy domains as well as their coupling effects, the models describing the behavior of MEM devices are quite complex and usually computationally too expensive for a fully coupled treatment on the device level, for instance by the finite element method. We present an approach that allows for the automated extraction (implemented as a MATLAB-based toolbox) of multi-energy domain coupled macromodels with acceptable computation times. In this work, we perform measurements to validate the macromodels and to identify limitations
Experimentally Validated and Automatically Generated Multi-Energy Domain Coupled Model of a RF-MEMS Switch
No full textWe present a computationally efficient multi-energy domain coupled system-level model of an electrostatically actuated RF-MEMS switch exposed to squeeze film damping. The physically-based model is systematically derived and calibrated on the basis of a hierarchical modeling approach. The model shows excellent agreement with both static and dynamic measurements performed with a white light interferometer. Especially coupling effects, that are the increased damping and the spring softening whilst actuation, are correctly reproduced by the model. This demonstrates the power of our modeling approach and, in particular, the predictiveness w.r.t. `real world` experiments. Furthermore, the automatically generated model is suitable for direct implementation into standard EDA tools for IC’s, like CadenceTM and Mentor Graphics�
A Measurement Procedure of Technology-related Model Parameters for Enhanced RF-MEMS Design
No full textThe accurate design of Micro-Electro-Mechanical- Systems (MEMS) for Radio Frequency (RF) architectures (e.g., reconfigurable transceivers) relies on suitable models describing the static and, above all, the dynamic electromechanical and electromagnetic behaviour of moveable structures. Such models usually include multiple parameters, whose values depend on the adopted manufacturing technology, as well as the uncertainty sources affecting the process itself. As a consequence, measuring the technology-related model parameters of a given class of MEMS structures is essential to estimate and to reduce, at an early design stage, possible mismatches between simulation results and device performances. In order to address this issue, in this paper we describe a procedure to measure the parameters describing the behaviour of RF-MEMS switches that are most severely affected by residual mechanical stress and surface roughness. The validity of the proposed methodology is confirmed by the good accordance between simulation and experimental results
COMSOL API based Toolbox for the Mixed-Level Modeling of Squeeze-Film Damping in MEMS: Simulation and Experimental Validation
No full textWe present an easy-to-use toolbox for the automated generation of reduced-order mixed-level models for the evaluation of squeeze-film damping in microelectro-mechanical systems. The toolbox is programmed in JAVA and heavily exploits the functionality provided by the COMSOL API. The results obtained from mixed-level model simulation performed in COMSOL Multiphysics agree very well with experimental data. A benchmark of the mixed-level model against other state-of-the-art analytic squeeze-film damping models shows that the mixed-level model is the one with the highest accuracy
Electromechanical and Electromagnetic Simulation of RF-MEMS Complex Networks Based on Compact Modeling Approach
No full textRF-MEMS, i.e. MicroElectroMechanical-Systems for Radio Frequency applications, have been attracting the interest of the scientific community for more than one decade, thanks to their high performance and large reconfigurability. The employment of RF-MEMS based devices and networks, like varactors, switches, phase-shifters, impedance matching networks and so on, within transceivers platforms, is the key to extend their functionalities and supported services. In this scenario, it is straightforward that the proper simulation of RF-MEMS devices and networks is a critical aspect to be faced, aiming at their integration within functional blocks based on standard semiconductor technologies. Our contribution reports on the exploitation of a MEMS compact model software library, previously developed by some of the authors, in order to simulate the coupled electromechanical and RF behavior of RF-MEMS devices/networks within a commercial ICs development framework, i.e. Cadence©. Such an approach enables the fast and accurate simulation of the mixed-domain behavior of RF-MEMS, as well as the hybridization of RF MEMS and CMOS blocks within the same schematic
Verification of a nonlinear model of a viscously damped ohmic RF-MEMS switch at varying ambient pressure conditions
No full textWe present a physically-based and multi-energy domain coupled reduced-order model that allows for the predictive simulation of the dynamic response of RF-MEMS switches. The coupling effects occurring during dynamic operation, namely increased damping due to the decreasing gap height and electrostatic spring softening are correctly implemented in the model and, therefore, accurately reproduced. The model is able to account for varying ambient pressure conditions and shows good agreement with measurements at pressure levels from 200hPa to 960hPa
Verifizierung eines nichtlinearen Modells für einen gedämpften ohmschen HF-Schalter bei unterschiedlichen Druckbedingungen
No full textKurzfassung
In diesem Beitrag wird ein physikalisch basiertes und elektromechanisch-fluidisch gekoppeltes Makromodell für einen mikromechanischen Hochfrequenzschalter abgeleitet und validiert. Mit Hilfe des prädiktiven Makromodells lässt sich sowohl die viskose Dämpfung, die sich bei Auslenkung des Schalters nichtlinear verändert, als auch die Verschiebung der Resonanzfrequenz des Systems aufgrund der elektrostatischen Kräfte korrekt beschreiben. Das Modell liefert daher eine sehr gute Übereinstimmung mit Messungen im Druckbereich von 200hPa bis 960hPa, die mittels eines Weißlichtin-terferometers in Kombination mit einer Vakuumkammer durchgeführt wurden.
Abstract
We present a physically-based and multi-energy domain coupled reduced-order model that allows for the predictive simulation of the dynamic response of RF-MEMS switches. The coupling effects occurring during dynamic operation, namely increased damping due to the decreasing gap height and electrostatic spring softening are correctly implemented in the model and, therefore, accurately reproduced. The model is able to account for varying ambient pressure conditions and shows good agreement with measurements at pressure levels from 200hPa to 960hPa
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