RF MEMS

Tout d'abord louanges et remerciements à Dieu pour m'avoir donné le courage et la force de terminer ce modeste travail. Je tiens à remercier mon directeur de thèse, M. Miloud KACHI, pour ses multiples conseils, suggestions et pour toutes les heures qu'il a consacrées à établir cette recherche. J'aimerais également lui dire à quel point j'ai apprécié sa grande générosité, disponibilité et ses qualités d'écoute et de compréhension. Cela a été un grand privilège pour moi d'avoir coopérer avec Monsieur le Professeur Lucien DASCALESCU du laboratoire d'étude aérodynamique IUT d'Angoulême de l'université de Poitier. Je tiens à lui adresser mes chaleureux remerciements pour ses remarques et conseils pertinents. Mes remerciements s'adressent également à Messieurs Karim MEDLES et Thami ZEGHLOUL pour toute leur aide, leur précieux conseils et leurs encouragements continus qu'il m'a prodigué durant la réalisation de cette thèse et leur confiance à mon égard. Je suis reconnaissant à Messieurs: Marian-Bogdan NEAGOE et Gontran RICHARD, doctorants à l'IUT d'Angoulême, pour leurs aides précieuses à la réalisation des manips. J'adresse tous mes remerciements à Professeur Ahcene LEMZADMI pour avoir accepté de présider mon jury. Mes remerciements vont également à Messieurs : Lazhar HEROUS, Noureddine ZOUZOU et Mokdad REMADNIA qui m'ont fait l'honneur d'examiner, évaluer et juger cette thèse. Mes remerciements s'adressent aussi à tous les membres de l'Institut PPRIME, de l'IUT d'Angoulême, de l'Université de Sidi-Bel-Abbès et de l'Université de Guelma, qui ont été proches de moi ces trois dernières années.

A microelectromechanical system (MEMS) sound waveguide is considered as a transmission line for RF signals. We analyze a device geometry of a straight one-dimensional microsize silicon rod, where a longitudinal acoustic wave is generated and detected using capacitive transducers. Linear, isotropic, and nondispersive acoustic-wave propagation is assumed. Based on the calculation of the electromechanical impedance, an electrical equivalent model is derived for the acoustic transmission line. A numerical example and a comparison to measured properties of a MEMS-transmission-line resonator shows that the characteristic impedance level of the waveguide is typically high, which causes challenges for matched termination. Solutions to overcome the matching problems are discussed.

Stabilization of the resonance frequency in thin-film acoustic devices to variations in environmental conditions is commonly reduced to the passive or active compensation of a single factor (usually temperature) and the isolation or addition of a separate correction circuit for every other factor (e.g., pressure and mass loading). In this work, the possibility of dual-factor compensation is proposed, where the response of a multi-layered thin structure to both temperature and ambient pressure variation vanishes due to the choice of intrinsic parameters (materials and thickness ratios). The response functions are derived for the S 0 Lamb mode at long wavelengths in an explicit analytical form in terms of bulk material characteristics. It is demonstrated that the dual-factor intrinsic stabilization requires at least a three-layered structure and can be achieved for materials commonly used in temperaturecompensated devices (aluminum nitride, fused silica, and aluminum). Identification of the key material characteristics governing the existence of a stability solution can serve for a targeted search of such composites and implementation of new thin-film dual devices.

Contact-less charging process has been found to constitute a compensation mechanism to dielectric charging of MEMS capacitive switches. The present paper aims to provide a better knowledge of induced charging mechanisms that appear in HF PECVD silicon nitride films. The characteristics of this process as well as the degree of compensation are investigated for different stressing field intensities of both polarities in MEMS capacitive switches. The experimental results indicate that the degree of compensation in HF PECVD SiN x films seems to increase with the intensity of the applied electric field and it is also affected by the polarity of the stressing bias. A new theoretical model that describes the build-up of induced charging is also proposed. Taking into account that the electric field during contact-less charging is quite low, the model assumes that induced charging arises from charge displacement inside the film through hopping conduction processes.

The dielectric charging in MEMS capacitive switches is a complex effect. The high electric field during pull-down causes intrinsic free charge migration and dipole orientation as well as charge injection. The macroscopic dipole moment of the first two mechanisms is opposite to the one arising from charge injection. This causes partial compensation hence mitigates the overall charging and increases the device lifetime. The charging due to intrinsic free charge migration and dipole orientation can be monitored under contactless electric field application in the pull-up state. The paper investigates the characteristics of contactless charging and compares them with the ones of contacted charging. The characteristics of the discharging process that follows each charging procedure are also presented.

A study of field emission process in MEMS-based capacitor/switch-like geometries is presented. High resolution current-voltage characteristics up to breakdown have been obtained across micro-gaps in fixed-fixed Metal-Air-Metal and Metal-Air-Insulator-Metal structures. In metallic devices the I-V dependence reveals Fowler -Nordheim theory effects. In the presence of insulator the process is found to be limited by the film conductivity following Poole -Frenkel dependence. The data analysis reveals the major importance of surface asperities on the onset of the field emission process while it is also presented that charge transfer may occur between metal and insulator surfaces even in the presence of micrometer scale gaps.

Kelvin probe method has been directly applied to capacitive MEMS switches in order to investigate temperature activated mechanisms in PECVD Silicon Nitride (SiN x ) films. The bulk discharge current of MEMS capacitive switches has been determined for different charging and discharging temperatures, in the range of 300-400 K. The increase of discharging temperature leads to an increase of the magnitude of the bulk discharge current and the relaxation time of the discharging process is found to be thermally activated. Finally, it is shown that the increase of charging temperature assists trapping at centers characterized by time constants even longer than the time window of observation, i.e. 10 4 s.

The present work presents a new method to calculate the discharge current in the bulk of dielectric films of MEMS capacitive switches. This method takes into account the real MEMS switch with non uniform trapped charge and air gap distributions. Assessment of switches with silicon nitride dielectric film shows that the discharge current transient seems to obey the stretched exponential law. The decay characteristics depend on the polarization field's polarity, a fact comes along with experimental results obtained from thermally stimulated depolarization currents (TSDC) method used in MIM capacitors.

A simulation model for static analysis of a doubly supported capacitive MEMS RF switch has been con- structed using electrical equivalencies. Energy-conserving large-displacement macro models for beam deflection, gap capacitance, electrostatic force, and mechanical con- tact are utilized. A one-dimensional nite-dierence ap- proach is utilized. The model is capable of reproduc- ing the large-displacement beam deflection prole. The static model is veried by comparing APLAC r simula- tion results with measured CV characteristics. The re- sults show that the model correctly reproduces the CV characteristics, including the performance at contact.

This paper describes the design principles of electrostatically actuated microelectromechanical capacitors. Key properties, such as capacitance tuning range, quality factor (Q), different control methods, thermal stability, effect of radio frequency signal on capacitance and gas damping are examined. Experimental devices were designed and fabricated using the design principles. The two-gap capacitor has a measured nominal capacitance of 1.58 pF and achieves a tuning range of 2.25:1 with parasitics. When all parasitic capacitances to the substrate are extracted the measured nominal capacitance is 1.15 pF and the tuning range is 2.71:1. The device is made of electroplated gold and has a Q of 66 at 1 GHz, and 53 at 2 GHz. In addition, two-and three-state capacitors were designed, fabricated and characterized.

High motional resistance and incompatibility with post-CMOS fabrication due to thermal budget constraints are imperative issues associated with the back-end-of-line integration of lateral extensional vibrating micromechanical resonators. This paper presents piezoelectric ZnO-on-nickel resonators as a viable means for mitigating both of the issues. Lateral extensional mode resonators equipped with thin-film piezoelectric transducers can exhibit much lower motional impedances than their capacitive counterparts due to piezo-transducers’ higher electromechanical coupling coefficients. Meanwhile, the employment of electroplated nickel as the structural material allows the process temperature to be kept lower than 300 °C, which is low enough for the post-CMOS resonator fabrication. In this work, various geometrical rectangular and square plates resonators are investigated. Moreover, parallel combination of several resonators into a mechanically coupled array was explored as a systematic a...

The design of a single-band singly-layered reflectarray fed by a circularly polarized 2x2 microstrip patch antenna array with corporate feeding to be used in K-band (18.7–19.2 GHz) is proposed in this paper. It is demonstrated by simulations and measurements that the axial ratio bandwidth performance of the reflectarray depends strongly on the circularly polarization purity of the feeder. Simulated and measured results revealed that the complete reflectarray exhibits good performance in terms of input impedance with -10 dB input reflection coefficient bandwidth of 19.0 %, radiation pattern with 3 dB axial ratio bandwidth of 10.55 % and 3 dB gain bandwidth of 2.64 %.

The pseudo-Hall effect in n-type single crystal 3C-SiC(1 0 0) with low carrier concentration has been investigated. Low pressure chemical vapor deposition was used to grow the single crystal n-type 3C-SiC(1 0 0) and Hall devices were fabricated by photolithography and dry etch processes. A large pseudo-Hall effect was observed in the grown thin films which showed a strong dependence on the crystallographic orientation. N-type 3C-SiC(1 0 0) with low carrier concentration shows a completely different behavior of pseudo-Hall measurements as compared to the p-type 3C-SiC(1 0 0). Contrary to p-type, the effect is maximum along [1 0 0] crystallographic orientation and minimum along [1 1 0] orientation. Moreover, the observed pseudo-Hall effect is 50% larger than p-type with higher carrier concentration grown by the same process which makes n-type 3C-SiC(1 0 0) with low carrier concentration more suitable material for designing highly sensitive micro-mechanical sensors.

Recent advances in temperature-compensation for FBAR (Film Bulk Acoustic Resonators) have brought this technology forward as a serious contender in the oscillator marketplace. As with any mechanical resonator oscillator, a cost-effective hermetic package combined with circuit technology are critical for commercial application. Billions of FBAR duplexers have been fabricated using Avago Technologies' wafer-scale packaging process, whereby a silicon lid wafer is Au-diffusion-bonded to a base FBAR wafer to make a robust, hermetic package. This paper presents a method for integrating circuitry into the lid wafer to form a sub-0.1 mm 3 , sub mW, 1.5 GHz temperature-compensated chip-scale oscillator. Circuit integration, testing and performance will be discussed. I.

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This paper describes the thin‐film fabrication process and the performance of 60‐GHz aperture‐coupled microstrip patch antennas printed on fused quartz substrates. It is shown that their characteristics (input impedance, axial ratio) are strongly modified by residual air gaps located between the two substrates of the antenna. In particular, FDTD simulations demonstrate that these parasitic effects can be minimized by using two ground/reflecting planes and by keeping the thickness of the air layer thinner than λ0/250, where λ0 is the free‐space wavelength. To face this technological problem, two intermediate metal and adhesive (low‐temperature) wafer bonding techniques, respectively based on indium and polymer layers, have been developed and validated experimentally for linear and circular polarization patch antennas and arrays. The lift‐off fabrication process is also described. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 41–47, 2004; Published online in Wiley Inte...

Each of the various methods for mixed-mode load-pull measurements, which can be found in literature, has its own advantages and disadvantages. In this publication, we analyze two of the most commonly used setups and a third setup of which we provided an initial treatment in a previous publication. We investigated the impact of 180°hybrids on the tuning capabilities of a mixed-mode load-pull system. Furthermore, we provide a rule-of-thumb to easily estimate this impact using only some specifications of hybrids. For all analyzed setups, we use measurement results to show that the tuning range of the newly proposed setup is superior compared to the other setups, though hardware effort and tuning complexity are greater.

In the proposed beam design, geometrical variations in terms of structure shape, material, gap, introduction of holes and changing the length and width of anchor have led to good RF performance. The holes in the beam (maximum up to 60% of total area of upper electrode) not only make the smooth mechanical movement of the beam but also result in low spring constant. The designed RF-MEMS switches are actuated electrostatically, and can be operated at low pull-in voltage, ranging from 0.5 V to 22 V with negligible power consumption. Proposed RF MEMS switches can easily be integrated in mobile RF front end section alongwith microstrip antenna in order to provide reconfigurabilty in frequency. Various shapes of planar antenna are also discussed which are suitable with proposed shunt switches. The effect of microstrip line and coplanar waveguide as transmission line are also studied.

In the proposed beam design, geometrical variations in terms of structure shape, material, gap, introduction of holes and changing the length and width of anchor have led to good RF performance. The holes in the beam (maximum up to 60% of total area of upper electrode) not only make the smooth mechanical movement of the beam but also result in low spring constant. The designed RF-MEMS switches are actuated electrostatically, and can be operated at low pull-in voltage, ranging from 0.5 V to 22 V with negligible power consumption. Proposed RF MEMS switches can easily be integrated in mobile RF front end section alongwith microstrip antenna in order to provide reconfigurabilty in frequency. Various shapes of planar antenna are also discussed which are suitable with proposed shunt switches. The effect of microstrip line and coplanar waveguide as transmission line are also studied.

A new optically controlled reconfigurable antenna for cognitive radio is presented. The antenna can operate at an ultra-wideband and three narrow bands by controlling four photoconductive switches. The bandwidth of the ultra-wideband is 2.65 to 10.3 GHz. The bandwidths of three narrow bands are 7.10 to 8.01 GHZ, 3.55 to 5.18 GHz, and 5.12 to 6.59 GHz, respectively.

A MEMS cantilever based resonant device for gas monitoring actuated and sensed piezoelectrically, has been designed, simulated, fabricated and tested. Aluminum Nitride (AlN) has been used as active material to implement the piezoelectric actuator and sensor. Simulation performed using COMSOL and measurements show a very good agreement. The final system, the full sensor for gas monitoring, allows the measurement of gas density and viscosity at temperatures between 0 and 65 °C and pressures between 1 and 10 bar abs. with accuracies of <0.03 kg/m 3 and 6% respectively. The second technological run has shown significant results at the same conditions, respectively of < 0.02 kg/m 3 and < 2% for density and viscosity.

Microelectromechanical Systems (MEMS) are devices made up of several electrical and mechanical components. They consist of mechanical functions (sensing, thermal, inertial) and electrical functions (switching, decision making) on a single chip made by microfabrication methods. These chips exhibit combined properties of the two functions. The size of system has characteristic dimensions less than 1mm but more than 1μm. The configuration of these components determine the final deliverables of the switch. MEMS can be designed to meet user requirements on any level from microbiological application such as biomedical transducers or tissue engineering, to mechanical systems such as microfluidic diagnoses or chemical fuel cells. The low cost, small mass and minimal power consumption of the MEMS makes it possible to readily integrate to any kind of system in any environment. MEMS are faster, better and cheaper. They offer excellent electrical performances. MEMS working at Radio frequencies are RF MEMS. RF-MEMS switches find huge market in the modern telecommunication networks, biological, automobiles, satellites and defense systems because of their lower power consumptions at relatively higher frequencies and better electrical performances. But the reliability is the major hurdle in the fate of RF MEMS switches. Reliability mainly arises due to the presence of residual stresses, charging current, fatigue and creep and contact degradation. The presence of residual stresses in switches the S-Parameters of the switches are affected badly and the residual stress affects the final planarity of the fabricated structure. Design and simulation of an RF-MEMS switch is proposed considering the residual stresses in both on and off state. The operating frequency band is being optimized and the best possible feasible fabrication technique for the proposed switch design is being analyzed. S-Parameters are calculated and a comparison for the switches with stress and without stress is performed in FEM based HFSS software.

Although large electronic systems can be constructed almost entirely with digital techniques, many systems still have analog components and current mirror is the core structure for almost all analog and mixed mode circuits. It determines the performance of analog structures, which largely depends on their characteristics. In this paper, we have analyzed a basic type as well as a cascade type of current mirror using enhancement type MOSFET and study different parameters like minimum output voltage, equivalent resistance and output sink current characteristics etc.

The following work presents the analytical, numerical and experimental characterization of a novel piezoelectric aluminum nitride MEMS bandpass filter. In contrast to multi-pole filters employing distinct mechanically or electrically coupled resonator building blocks, the passband of the device in the present work is defined by the proximity of two natural contour modes of vibration in a single annular resonator. The proposed implementation, albeit currently limited to dual-pole filters, results in smaller form factors and reduces device sensitivity to across wafer fabrication tolerances. A filter with 4.8 dB of insertion loss, a 22.4 MHz center frequency, a TCF of approximately -20 ppm/ • C, and 0.5% fractional bandwidth at -3 dB is demonstrated.

Dielectric charging is a major reliability issue preventing commercialisation of RF MEMS capacitive switches. To date two major modes have been considered as responsible for the charging of the dielectric films in RF MEMS. The one takes place during the pull-down state and therefore it is called contacted or injection charging, whereas the second occurs when the bridge is still in the up state and is referred to as contactless or induced charging. Experimental results supporting contactless charge injection as an additional charging mechanism in RF MEMS capacitive switches are presented.

The discharging processes in silicon nitride dielectric film of RF-MEMS capacitive switches are investigated for the first time. The study includes the dependence of discharging as a function of temperature that allows the detection of thermally activated mechanisms. The discharging time constants were found to depend only on temperature and not on the actuation bias polarity.

The conduction mechanisms through a lead zirconate titanate (PZT) thin film grown by pulsed laser deposition with a La 0.67 Sr 0.33 MnO 3 (LSMO) buffer layer on epitaxial Pt (111) were assessed in the 230-330 K temperature range. X-Ray diffraction and transmission electron microscopy evidenced a columnar growth of (001)-and (011)-oriented PZT grains. The leakage current through the Pt/PZT/LSMO/Pt structure was then systematically measured. From current vs. time curves, a threshold voltage was found below which stable and reproducible current values are obtained, thus avoiding resistance degradation. The conduction mechanism changes from interface controlled at low temperatures to bulk controlled around room temperature. The hopping-type conductivity evidenced above 270 K is consistent with the extended defects and columnar microstructure of the PZT film.

Silicon dioxide and silicon nitride as well as other insulating materials are used in micro-electro-mechanical systems. However, their tendency for electrostatic charging diminishes the device reliability. The charging effect becomes significant when these devices are subjected to ionizing radiation. The irradiation induced charging depends on the nature of irradiation, the underlying metal layers and the metal-insulator interface properties. The sensitivity of RF micro-electromechanical systems to electromagnetic ionizing radiation is presented, taking into account the simulation of charge generation and the device structure.

This paper is situated in the context of heterogeneous integration of millimeter-wave communication circuits. It shows that VHDL-AMS models are well suited for the simulation of building blocks constituting an integrated communication system. Simplicity and reduced execution time are mandatory when it comes to the simulation of the behavior of an entire SiP. In particular, a VHDL-AMS model for RF MEMS capacitive shunt switches based on its equivalent circuit is presented. Subsequently, this model is, together with a transmission line model, applied to simulate the behavior of a mm-wave phase shifter employing RF MEMS shunt switches.

It is difficult to realize the built-in antenna for wideband systems, because a frequency bandwidth of the low profile antenna is narrow. A frequency tunable antenna is a technique for wideband characteristics. In this paper a low profile double resonance frequency tunable antenna using MEMS variable capacitors is presented. It has high efficiency over a wide frequency band. Through both resonant portions from 465 to 665 MHz, the efficiency of more than -4 dB and the VSWR of less than 3 are observed in the measurement using the variable capacitor of 0.4-0.9 pF.

This paper reports a novel design and analysis of RF MEMS switch with two movable electrodes to achieve a simultaneous improvement in actuation voltage along with the switching time. About 30% improvement in the actuation voltage along with a 50% reduction in switching time can be obtained with such design. Moreover a stiction free fabrication methodology is presented to fabricate the switch, which involves the use of two bulk micromachined silicon substrates bonded together.

We report the high-yield fabrication of SiCN doublyclamped nanomechanical resonator arrays for the specific detection of proteins. As a proof of concept, specific detection of Protein A has been demonstrated. The resonant frequencies of the individual resonators were determined using optical interferometry. The bare resonators displayed resonance frequencies of ~ 17 MHz. Immobilization of single domain antibody fragments resulted in frequency downshifts of ~ 341 kHz due to the added mass. Attachment of protein A yielded a further reduction of frequency by ~ 216 kHz. A much smaller frequency reduction of ~ 54 kHz was observed when the resonators are exposed to an identical solution containing no protein A.

Microelectromechanical systems (MEMS) is a multidiscipline area requiring knowledge in various STEM disciplines such as: mechanics, material science, chemistry, physics, and electronics etc.….A graduate course at the University of New Mexico focuses on learning theory of microfabrication and applying this knowledge through a hands-on problem-based learning project. The problem-based learning project focused on developing a MEMS electro-thermal actuator and the challenges associated with microfabrication. The hands-on experience was performed during the lab section of the course in a cleanroom environment. The course was designed to give students theoretical knowledge while giving them hands-on experience as a MEMS process engineer thus giving them experience in MEMS microfabrication. The present work focused on fabricating an aluminum electro-thermal MEMS actuator on a silicon wafer using photoresist as the sacrificial layer and measuring the displacement as a function of the applied voltage, which was performed as laboratory work supplementing the graduate course. Actuators with varying dimensions were developed. Stresses in the aluminum cantilever structure were reduced by controlling sputtering deposition parameters such as thickness and power. Removal of the sacrificial photoresist layer proved to be a limiting factor because a liquid etchant was used, which lead to issues with stiction. Care was taken to optimize the process of the electro-thermal actuators and reduce the amount of stiction and overall intrinsic stress present of the device. The results of this project were working devices and knowledge of process improvements to increase the efficacy of future work in this field.

Although large electronic systems can be constructed almost entirely with digital techniques, many systems still have analog components and current mirror is the core structure for almost all analog and mixed mode circuits. It determines the performance of analog structures, which largely depends on their characteristics. In this paper, we have analyzed a basic type as well as a cascade type of current mirror using enhancement type MOSFET and study different parameters like minimum output voltage, equivalent resistance and output sink current characteristics etc.

This paper presents a systematic development of an impedance tuner for use in S-band microwave networks which specifically targets the 2.45GHz ISM band to provide efficient automatic impedance matching under high-power operating conditions. Designed as a doublestub structure within the WR-340 waveguide, the proposed tuner is intended to work alongside a reflectometer in a closed-loop feedback system, utilizing reflectometer measurements to dynamically adjust impedance. This method facilitates stable and temperature-independent performance, making the tuner well-suited for online monitoring and control in industrial waveguide application. To achieve this, a combination of simulations and preliminary measurements using Agilent E5071c VNA and coax-to-waveguide (C2W) transitions were employed to validate the proposed tuner's stability and efficiency in real-time network parameter adjustment. Key findings in this work revealed capability of the backshort reflecting strong incident power and delivering about-78dB transmission at 2.45GHz highlighting the tuner's robustness and operational consistency. This provides a practical solution for precise impedance matching in industrial environment for reliable high-power microwave control while maintaining optimal performance.

This paper presents the advances done in the field of simulation and design applied to MEMS. It will be discussed some techniques to link different finite element softwares, especially COMSOL and ANSYS, in order to profit from all the advantages offered by each finite element code. Then, an explication is done on how we piloted ABAQUS using a Matlab routine. In a third and very important section, the use of reverse engineering method is described and applied to RF-MEMS (Radio Frequency-Micro Electro Mechanical System) switches. The applications for each of these methods will be explained.

A complete vector-2D micro-integrated sensors system for magnetic field measurement is proposed. The system consists of a micro-integrated Fluxgate magnetometer with front-end electronic circuitry based on second-harmonic detection. The magnetic core of the sensor is the VITROVAC 6025X deposited over the micro-integrated coils with the RF magnetron sputtering process deposition.

We present results for full-electrical characterization of a 64 MHz silicon bulk acoustic resonator with quality factor (Q) of 10 4 and achieving an insertion loss of -35dB without depending on sub-micron capacitive gaps. The high transduction results from using thermal actuation in addition to piezoresistive sensing. In contrast to typical capacitive bulk acoustic resonators, both transduction and Q increase when reducing the device thickness. To this effect, our s had 23dB less insertion loss than ones that were 25 thick, with the same lateral dimensions. We also present an equivalent circuit model which we show to be capable of providing a close fit to our experimental measurements.

This paper presents a low-actuation-voltage micro-electromechanical system (MEMS) capacitive shunt switch which has a very large bandwidth (4 GHz to 24 GHz). In this work, the isolation of MEMS switch is improved by adding two short high impedance transmission lines at the beginning and end of a coplanar waveguide (CPW). Simulating the switch demonstrates that a return loss (S11) is less than -26 dB for the entire frequency band, and perfect matching at 20 GHz in upstate position. A ramp dual pulse driver is also designed for reducing the capacitive charge injection for considering the reliability of the switch. The simulation results show that the shifting of voltage due to the capacitive charge is reduced by more than 35% of the initial value. Finally, the dynamic behavior of the MEMS switch is simulated by modal analysis and using CoventorWare to calculate the natural frequencies of the switch and its mode shapes. The switching ON and OFF time are 4.48 and 2.43 µs, respectively, with an actuation voltage of less than 15 V.

We have analyzed the implications of innovations in MEMS on Wireless Sensor Networks (WSN) and have modeled MEMS elements from a device prospective. We have commented on the advantages as well as the challenges that exist in this technology and described the important factors that need to be kept under consideration for the calculation of the reliability for practical implementation of MEMS based devices and the scope of modeling. We have executed the work on SUGAR of MATLAB; the proposal is then compared to the recent developments taking place and with the other experimental result which are reported. Thus a comprehensive modeling aspect of MEMS based elements of a WSN is shown. Modeling of tunable comb resonators, Vertically-shaped comb-resonators and thermal actuator has been shown and the implication of modeling in such devices has been shown. Various computations were implemented and results being given supporting the data from the experiments in recent years.

This theoretical work corresponds to the hope of extracting an energy present everywhere in the universe: that of the quantum vacuum. With the energy of the quantum vacuum as the only source, this article shows that it is theoretically possible, without contradicting EMMY NOETHER's theorem: 1/ to maintain a continuous periodic vibration of a piezoelectric bridge embedded at its two ends, 2/ to extract exploitable electrical power from it. These vibrations of the sensor part of the proposed MEMS have nothing in common with an impossible macroscopic "perpetual motion" because the energy of the quantum vacuum permanently powers the system. They are obtained by automatically controlling the deformation of a piezoelectric bridge. This cyclic deformation is created thanks to the Casimir force FCA, omnipresent, permanent and attractive, between two electrodes. This FCA force is controlled by an automatic Coulomb repulsive force FCO which is applied, thanks to the closure of a switch n°1 on a third electrode called Coulomb. The FCO Coulomb's force derives from the electric charges generated by the deformation of the piezoelectric bridge. The FCO force is in the opposite direction and with a greater intensity than the FCA. The FCO force appears and disappears at predetermined positions z1 and z2, thanks to the very close consecutive activation of two switches which automatically switch by the action of the electric charges appearing on the deformed piezoelectric bridge. The resultant of the applied forces, FCO-FCA, then straightens the bridge and gives it kinetic energy, giving it inertia which will be dissipated by the FCA force. The deformation of the piezoelectric bridge being reduced according to its electric charges, the switch n°1 opens again, immediately after its closure. Very quickly thereafter, the Coulomb electrode is then brought to ground, thanks to the switching-via an R.L.C circuit-of the switch n°2. The FCO force therefore disappears very quickly after its appearance. The kinetic energy acquired by the structure gives it an inertia which allows it to find or slightly exceed the initial position. The Casimir force, still present, then deforms the structure again. The system starts to vibrate. Each time switch n°2 close to ground, a current and voltage peak is generated. These periodic power peaks supply an autonomous electronic circuit (without any power supply) which transforms these signals into a usable DC voltage. In this article we will exclusively present the energy balance of the structure, and we will show that-unless mistaken-this balance is consistent with Miss Emmy Noether's fundamental theorem. For following parts: 1/ Putting into equations the dynamic behavior of the structure 2/ Creation of autonomous electronics for signal shaping 3/ Manufacturing microtechnology [7] [8] [9] See the articles published on Academia at the addresses:

This theoretical work corresponds to the hope of extracting, without contradicting EMMY NOETHER's theorem, an energy present throughout the universe: that of the spatial quantum vacuum.

This article shows that it should be theoretically possible to maintain a continuous periodic vibration of a piezoelectric structure, which generates electrical power peaks during a fraction of the vibration period.

Electronics without any power supply then transform these alternating current signals into a usable direct voltage.

To manufacture these different structures, we also present an original microtechnology for producing the regulation and transformation electronics, as well as that necessary for controlling the very weak interfaces between the Casimir electrodes and that of the return electrodes.

These vibrations are obtained by controlling automatically and at appropriate instants the action of the attractive Casimir force by a repulsive Coulomb force applied to return electrodes.       The Casimir force appearing between the two electrodes of a reflector deforms a piezoelectric bridge, inducing a displacement of the barycenter of the ionic electric charges of the bridge.

This internal piezoelectric field attracts opposing moving charges, from the mass, on either side of the piezoelectric bridge .They are used – after their homogenization - by a Coulomb force opposed and greater than the Casimir force.
During the homogenization of the electric charges between the face 1 and the return electrode, periodic current peaks appear during a fraction of the vibration time of the device.
These current peaks crossing an inductance, spontaneously induce voltage peaks at the terminals of this device, which are transformed into a usable DC voltage thanks to proposed electronics without a power supply.
Casimir and Coulomb forces, vibrations, current, or voltage peaks appear spontaneously and without external energy    input. Everything is only a consequence of the existence of the Casimir force due to the quantum fluctuations of the    vacuum.
This set does not seem to contradict Thermodynamics’ law and Emily Noether's theorem.