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Radiofrequency microelectromechanical system (RF-MEMS) switches are utilized across a broad spectrum of industries, including telecommunications, aerospace, defense, and smartphone technology.Herein, we proposed a new numerical and simulation analysis approach for spring constant (k) values as the characteristic mechanical parameters of RF MEMSs using the modified energy method (MEM). The proposed RFMEMS switch was analyzed and simulated using the COMSOL package, and the findings confirmed that the alteration in the position and length (L) of the beams not only diminishes k significantly but also provides actuation-voltage VAC ultrasensitive structures and great concomitance between numerical and simulation k and VAC values. VAC value for the L-dependent numerical k (0.07 N m-1 ) was calculated to be 1.61 V which was validated with simulation outputs at 0.08 N m-1 and 1.80 V for k and VAC, respectively. Additionally, the switching time (ts), Von Mises Stress (VMS), natural frequency (fn) and mass (m) characteristic mechanical parameters were found to be 25.60 µs, 4.50 MPa, 3118.60 Hz, and0.21 ng, respectively. RF analysis was conducted in HFSS, revealing promising simulation results for the studied RF-MEMS switches. The return loss demonstrates excellent performance, registering better than -1 dB at 46 GHz. Furthermore, the insertion loss is noteworthy, exceeding expectations with values better than -0.7 dB at 46 GHz. Importantly, the isolation is impressive, exceeding -25 dB across the frequency range from 40 GHz to 35 GHz, all achieved with a modest actuation voltage of 1.8 V. This study contributes valuable insights intothe design and application of low-actuation-voltage RF-MEMS switches. [ABSTRACT FROM AUTHOR]

Radio-frequency (RF) micro-electro-mechanical-system (MEMS) switches are widely used in communication devices and test instruments. In this paper, we demonstrate the structural design and optimization of a novel RF MEMS switch with a straight top electrode. The insertion loss, isolation, actuator voltage, and stress distribution of the switch are optimized and explored simultaneously by HFSS and COMSOL software, taking into account both its RF and mechanical properties. Based on the optimized results, a switch was fabricated by a micromachining process compatible with conventional IC processes. The RF performance in the DC to 18 GHz range was measured with a vector network analyzer, showing isolation of more than 21.28 dB over the entire operating frequency range. Moreover, the required actuation voltage was about 9.9 V, and the switching time was approximately 33 μs. A maximum lifetime of 109 switching cycles was obtained. Additionally, the dimension of the sample is 1.8 mm × 1.8 mm × 0.3 mm, which might find application in the current stage. HIGHLIGHTS: • A new type of top electrode for a switch is proposed in this paper. The sample size is 1.8 mm × 1.8 mm × 0.3 mm. The design was miniaturized to make it easy to integrate. • The switch has a lower drive voltage (9.9 V) and a faster response time, so that the switching time was increased to 33 μs. In addition, the isolation was greater than 21.28 dB over the operating frequency range, achieving excellent RF performance. • A micro-machining process compatible with the traditional integrated circuit process was used to manufacture the switch, and the design realized high reliability. The maximum lifetime of the switch is 109 cycles. [ABSTRACT FROM AUTHOR]

In this paper, we investigate dielectric charging process in capacitive structure dielectrics under bias voltage. We particularly focus on the case of Si3N4 dielectric layers. The main defects in silicon nitride involved in electronic transport are identified as shallow traps. A new model for dielectric charging is presented with trap assisted tunneling effect as interfacial electronic transport mechanism and Frenkel-Poole and hopping current as bulk transport mechanisms. Thanks to this model, electric field and charge carrier distribution in the dielectric layer can be calculated. The actuation bias shift versus time, which is responsible for RF capacitive structure failure, can also be determined. We find that after a 300 s actuation, the charge is concentrated in few nm in the dielectric layer and a voltage shift of few volts is calculated, depending on dielectric characteristics. [ABSTRACT FROM AUTHOR]

A chemical solution deposition procedure was developed for lead nickel niobate-lead zirconate titanate (0.3)Pb(Ni0.33Nb0.67)O3–(0.7)Pb(Zr0.45Ti0.55O3) ferroelectric thin films. On tailoring the heat-treatment conditions and excess lead content, the average grain diameters could be varied from 110 to 270 nm. Dielectric permittivities ranging from 1350 to 1520 and a transverse piezoelectric coefficient e31,f as high as -9.7 C/m2 were observed for films of about 0.25 μm in thickness. The permittivity and piezoelectric response increased for samples with larger grain size. Higher thermal budgets also imposed higher levels of in-plane tensile stress on the perovskite layer; the imposed stress reduced the remanent polarization for the samples. Nonetheless, samples processed at higher temperatures showed larger average grain diameters and higher extrinsic contributions to the properties. [ABSTRACT FROM AUTHOR]

The aim of this paper is to investigate the bending characteristics of a low‐pass RF MEMS (radio frequency microelectromechanical system) filter based on a flexible substrate. The proposed filter is achieved by complementary split ring resonator and MEMS bridge which are fabricated on a flexible LCP (liquid crystal polymer) substrate. The bending characteristics of the filter are revealed by theory, simulation and measurement. The experimental results demonstrate that the return loss of the filter deteriorates and the cut‐off frequency of the filter decreases with the curvature of the flexible substrate increasing. The cut‐off frequency is 38.5 GHz and the return loss is −22.7 dB at 10 GHz with the flat substrate. When the curvature of the substrate increases to 28.57 m–1, the cut‐off frequency decreases to 14.8 GHz, and the return loss deteriorates to −5.7 dB at 10 GHz. [ABSTRACT FROM AUTHOR]

In this study, the deflection and stiffness of a micro cantilever beam with a rectangular notch are derived analytically by considering a non-uniformly distributed load as a cause of deflection, since the shape of a distributed load at the exact collapse time is not uniform in the real scenario. In order to calculate the deflection, due to the design of the beam structure, the superposition method is employed as well as the fundamental principles of mechanics. Moreover, it is also utilized in the subsequent stiffness calculations. Particularly, the stiffness concept is discussed under three different subsets: natural, actuation, and release stiffness, as they are essentials for the switching operations. In addition to the analytical study, FEM simulations are also carried out using CoventorWare in order to compare with the derived models. As the results reveal that accuracies of both the analytical models and simulations are acceptable, this study provides a utilitarian framework for designing different complex MEMS. [ABSTRACT FROM AUTHOR]

Abstract: A novel concept of reconfiguring high Q‐factor iris filters, to operate in different frequency bands, is presented. Compared to traditional iris filters, the air‐filled irises are here replaced with dielectric substrate, similarly as the concept of substrate integrated waveguide. By controlling RF MEMS switches placed on the dielectric substrate, the equivalent iris width and thickness, and the resonant cavity length can be reconfigured simultaneously. As a demonstration of the concept, this article has proposed a third‐order bandpass filter consisting of 3 waveguide sections made of brass and 4 inverters fabricated on Rogers RT/duroid 5880 substrate. Constant absolute bandwidths between different states and theoretical unloaded Q‐factor of 1800 are achievable in our approach. [ABSTRACT FROM AUTHOR]

Design, fabrication and characterization of a novel RF switch is proposed in this paper. The multiport RF MEMS switch provides a single input multiple output novel topology suitable for satellite payload applications. A single ETA is used to switch the device from one mode to another. When a voltage difference is applied across the electrode pads of ETA, and depending on the configuration, the actuator actuates forward or backward in plane producing either a quad or dual output respectively. The reflection loss and insertion loss are improved effectively. Measurement results show that in `dual mode’ position, the input reflection coefficient (S11) is less than − 50 dB with the forward transmission coefficient (S21) better than − 2 dB at 0-15 GHz. At ‘quad mode’, position, the input reflection coefficient (S11) is less than − 55 dB with the forward transmission coefficient (S21) better than − 4 dB at 0-15 GHz. The larger than 50 dB over 0-15 GHz isolation realized in both modes of operation ensures dual and quad mode outputs without information loss. The actuation voltage is reduced to 4.5 V. The measured power handling capability can reach up to 35 dBm while the power consumption of the switch is 50 mW. This compact RF MEMS capacitive switch possesses excellent performances in terms of low insertion loss, high isolation, low power and high power handling capability. [ABSTRACT FROM AUTHOR]

In this paper, a novel dual band dual feed multiple input multiple output reconfigurable antenna is designed. On-plane printing methodology is focused in designing the antenna. To implement the design, a circular Defected Ground Structure (DGS) with concentric split ring is employed beneath the signal plane and the reconfiguration is attained without using any switching elements. The signal plane comprises of octagonal ring pattern with orthogonal dual feed arrangement. The antenna prototype has the dimension of 0.66λ × 0.66λ, where the octagonal ring is of 0.34λ. An impedance of 50 Ω is maintained in designing the prototype. The dual band has been achieved by the periodic property of split ring employed within the circular DGS in the ground plane. Alternate shorting of ports has been performed to attain the reconfiguration. The prototype is designed to be utilized in public safety and aeronautical radio navigation under US standards at 0.816 and 1.072 GHz with reflection coefficients of − 17 and − 21 dB respectively. The patterns have been reconfigured by terminating one of the ports with 50 Ω impedance termination. This resulted in change of beam directions, attaining pattern reconfiguration. [ABSTRACT FROM AUTHOR]

This paper presents design and simulation of uniform structured RF MEMS capacitive shunt switch using FEM tool and HFSS software. The switches with different shaped meanders and perforations which result in less spring constant, less pull-in voltage, high isolation loss, high switching speed and low insertion loss have been designed. From the simulated results it is observed that the rectangular perforations gives the better results, when compared with square and cylindrical shaped perforations. Comparative study is done for zigzag, plus and three square shaped meander along with rectangular perforations on each structure. When the gap between the dielectric and the movable beam is 0.8 µm, the up state capacitance for HfO2 is 4.06fF and for Si3N4 is 3.80fF. The downstate capacitance for HfO2, Si3N4 is 49fF, 26.9fF respectively. The capacitance ratio is 120.6. Poly-tetra-fluoro-ethylene material is given for the movable beam whose young’s modulus is 0.4 GPa and the spring constant is calculated theoretically for each structure; by using this the pull in voltage and the settling time are calculated. Step switch with three square Meander has switching time 10.25 µs, pull in voltage as 2.45 V. By using HFSS 3-D electromagnetic model we observed the return loss (S11) is less than −60 dB, the insertion loss is less than −0.07 dB in the range of 1–40 GHz frequency and switch isolation (S21) is −61 dB at 28 GHz frequency. [ABSTRACT FROM AUTHOR]

The non-equilibrium electro-thermodynamic properties of magnetized plasma produced by a modified radio-frequency magnetron sputtering system were investigated in detail. The plasma was analyzed using Hall, Langmuir, and Faraday probes and optical emission spectroscopy, and numerical simulations were conducted to determine the electric and magnetic field profiles. It is found that the occurrence of lower hybrid resonance and excitation of helicon waves are satisfied locally along the plasma profile ( Z ). This unusual effect in magnetron sputtering systems plays an important role in the increase of the electrons and ions temperature improving the quality of the films produced. Films of complex structure as hydroxyapatite that have biomedical applications were produced along the Z to confirm our plasma results. The films were characterized by performing grazing incidence X-ray diffraction using synchrotron radiation, X-ray photoelectron spectroscopy and atomic force microscopy. The microstructure analysis of hydroxyapatite films produced at different Z revealed that films with high crystallinities and with ideal stoichiometries (Ca/P = 1.67 ± 0.05) were produced within a magnetic cusp region (26 mm < Z < 32 mm). Based upon the results from plasma diagnostics and films characterization, we proposed a model of plasma of this system. The delivered energy by ions bombardment for films formation was determined and reached values around 8 eVs −1 Å −2 and plasma temperature of T ≈ 10 eV inside the magnetic cusp region. Finally, this work opens the possibility to produce coatings of other complex compounds by the fine-tuning of resonant waves and their high delivered energies in vacuum magnetized plasmas. [ABSTRACT FROM AUTHOR]

Bandpass (BP)-to-bandstop (BS) switchable filters using radio frequency microelectromechanical system switch are presented here. The filters are implemented in both single- and dual-band versions with variable fractional bandwidth (FBW). Tuning of transmission zeros (TZs) and transmission poles (TPs) for BP filter (BPF) and BS filter (BSF), respectively, is achieved in both single- and dual-band cases leading to reconfigurable selectivity. The first odd-mode frequency of the filter is suppressed using a fixed capacitor and the second odd mode is brought closer to the first even-mode with another variable capacitor to form the passband(s). The second capacitor tunes both the second odd mode and TZs (for BPF) or TPs (for BSF) minimizing the requirement of any extra tuning element. In a single-band fabricated BPF, tuning second odd mode gives the FBW variation of 9.3%–72.7% with TZ on the lower side and 5.6%–55.6% with TZ on the higher side of the passband. The 15-dB FBW of a single-band BSF having TP on both sides of the stopband varies over 5.2%–20.7%. The two passbands of a dual-band BPF independently vary over 4.5%–24% and 4.5%–13%. Also, the 15-dB FBW of the first and second stopbands of BSF independently varies over 6.5%–13.2% and 1.5%–3.6%, respectively. [ABSTRACT FROM PUBLISHER]

Multimode transceivers for the next generation of wireless devices require new and innovative frequency-agile microwave circuit designs to reduce their complexity, size, and cost. Intrinsically switchable frequency reconfigurable thin-film bulk acoustic resonators (FBARs) and filters that utilize these resonators are presented here for the very first time. Barium strontium titanate (BST) is a ferroelectric material that exhibits electric-field-induced piezoelectricity, which allows for the design of voltage controlled bulk acoustic wave devices. In this paper, a frequency reconfigurable resonator consisting of two series connected BST-based FBARs and a reconfigurable dual-band filter consisting of two 1.5 stage ladder-type bandpass filters are discussed. Their small size, simple design, and zero static power consumption make multifunctional ferroelectric thin-film devices attractive for use in adaptive and reconfigurable radios. [ABSTRACT FROM AUTHOR]

This paper presents an approach for restoring force enhancement to radio frequency (RF) micro-electro-mechanical systems (MEMS) switch with stiction-recovery actuation mechanism. It is based on additional anti-stiction electrodes which are inserted to the coplanar waveguide (CPW) between the signal line and ground planes of a RF MEMS switch. If the movable membrane sticks to the substrate, electrostatic force, as extra restoring force, generated by the bias voltage between the anti-stiction electrodes can promise restoring action. The designed device with the proposed approach is fabricated. The restoring force of the fabricated device had reached 75, 177 and 520 μN by the bias voltages of 0, 10 and 20 V, respectively. [ABSTRACT FROM AUTHOR]

This paper presents the design of a tunable capacitor that integrates two vertical comb-drive tunable capacitors and a parallel plate tunable capacitor. The parallel plate tunable capacitor is in the middle of the comb-drive tunable capacitors. The vertical comb-drive part has sets of fixed and moving fingers while the parallel plate has fixed and moving plates. The capacitor is fabricated using the MetalMUMPs microfabrication process, which has only one thick structural layer i.e. metal (20 μm nickel and 0.5 μm gold). The nickel of the metal layer is subject to residual stress gradients along its thickness. After release of the metal layer, the stress gradients bend the curve-up beams to raise the moving fingers and the moving plate of the capacitor above the substrate and the fixed plate. Hence, one structural layer (i.e. the metal) is used to form the moving and the fixed comb fingers without requiring two structural layers. Vertical comb-driven tunable capacitors offer high capacitance density when a large number of fingers with narrow gap are used. Therefore, high capacitance ratio and high quality factors can be achieved by using vertical comb-drives with in a relatively small device area compared to lateral comb-drives. The parallel plate driving part increases the displacement and capacitance ratio while reducing the actuation voltage required for driving the capacitor. The quality factor and tuning ratio of the fabricated tunable capacitor are 118.5 and 101% at 0.8 GHz; respectively at a driving voltage of 100 V. Based on the experimental results of the fabricated tunable capacitor, an optimized design is presented for both high tuning ratio and high quality factor. The tuning ratio of the optimized capacitor is found to be 143.1% at a 'pull-in' displacement of 9.5 µm and a 'pull-in' voltage of 90 V. The quality factors of the optimized capacitor are 520 at 0 V and 363.5 at 90 V, respectively at 0.8 GHz. The tunable capacitor achieves a displacement of more than one-half of the gap between the parallel plates without 'pull-in' effect. [ABSTRACT FROM AUTHOR]

In this paper, a novel microwave continuously tunable band-pass filter, based on nematic liquid crystals (LCs), is proposed. It uses liquid crystal (LC) as the electrooptic material to mainly realize frequency shift at microwave band by changing the dielectric anisotropy, when applying the bias voltage. According to simulation results, it achieves 840 MHz offset. Comparing to the existing tunable filter, it has many advantages, such as continuously tunable, miniaturization, low processing costs, low tuning voltage, etc. Thus, it has shown great potentials in frequency domain and practical applications in modern communication. [ABSTRACT FROM AUTHOR]

Defects in ceramic insulators like broken, cracked and punctured discs give rise to the initiation of partial discharge (PD) activities within the samples which has a detrimental effect on the insulator life. Hence it is important for the utilities to identify such defective samples as early as possible so that appropriate replacement strategies can be devised. The work presented in this paper involves the investigation of a number of cases of insulator defects, with the goal of developing an online RF-based PD technique for monitoring ceramic disc insulators. The three classes examined are a cracked ceramic insulator disc; a disc with a hole through the cap, and a completely broken insulator disc. The defective discs are considered individually and are also incorporated into strings of 2, 3, and 4 insulators. The captured RF pulses are processed by extracting wavelet packet based features. Feature reduction and selection is carried out and classification results are obtained. To classify the discharges arising from different types of defects, an artificial neural network (ANN) algorithm is applied to the extracted features, and recognition rates of more than 95% were reported for each class. The results of preliminary field tests carried out on a 40 feet high test transmission tower are also reported and their analysis showed good discrimination between the different defect types. [ABSTRACT FROM AUTHOR]

This paper deals with the modeling of capacitance in an actuated RF MEMS switch where the beam layer forms tilted contact at the edges and touches completely with the dielectric layer at the center. The tilted and overlapping sections of the beam are modeled separately and combined with the effect of etched holes to estimate the overall capacitance formed between the beam and central part of coplanar waveguide. Effects of beam width, dielectric thickness, and the air gap between beam and dielectric layer on total capacitance of the switch are analyzed. RF analysis and beam length optimization has also been done to ensure an efficient grounding of signal in the transmission line. Model and simulated values using Coventorware MEMS plus 4.0 are compared in different configurations and percentage of errors are also estimated. For beam height variation of 1–2.25 μm, the error is within ±8%, while for varying dielectric thickness of the layer from 0.15 to 0.3 μm and beam width variation of 40–70 μm shows an accuracy within ±6%. [ABSTRACT FROM AUTHOR]

In this paper, a silicon-based radio frequency micro-electromechanical systems (RF MEMS) pattern reconfigurable antenna for a Ka-band application was designed, analyzed, fabricated, and measured. The proposed antenna can steer the beam among three radiating patterns (with main lobe directions of -20°, 0°, and +20° approximately) at 35 GHz by switching RF MEMS operating modes. The antenna has a low profile with a small size of 3.7 mm x 4.4 mm x 0.4 mm, and consists of one driven patch, four parasitic patches, two assistant patches, and two RF MEMS switches. The active element pattern method integrated with signal flow diagram was employed to analyze the performances of the proposed antenna. Comparing the measured results with analytical and simulated ones, good agreements are obtained. [ABSTRACT FROM AUTHOR]

Spectrum of radio frequency (RF) communications is limited and expensive to install new applications. Free space optical (FSO) communication is a viable technology which offers enormous bandwidth, license free installation, inexpensive deployment and error prone links. The FSO links degrade significantly due to the varying atmospheric and weather conditions (fog, cloud, snow, haze and combination of these). We propose a hybrid FSO/RF communication system which adapts the varying nature of atmosphere and weather. For the adaption of varying atmosphere and weather scenarios, we develop a novel optimization algorithm. The proposed algorithm is based on the well-known puncturing technique. We provide an extrinsic information transfer (EXIT) chart for the binary and quaternary mapping scheme for the proposed communication system. We simulate the proposed algorithm for the hybrid communication system and analyze the system performance. The proposed algorithm is computationally less expensive and provide better performance gains over varying atmosphere and weather conditions. The algorithm is suitable for fast speed applications. [ABSTRACT FROM AUTHOR]

A new structure for RF MEMS resonators is demonstrated in UHF range. The presented resonator has the ability to work in multiple resonance modes by its specific anchor design. Also, its special electrodes are designed so that the desired mode at any time could be excited by embedding simple MOS switches. Since the resonance frequency of different modes could be adjusted by the inner radius of the resonator, the structure could be designed for wide range of arbitrary frequency differences between modes. Specific electrodes and anchors design guarantees low insertion loss and high quality factor in all modes. Modal and harmonic analysis verify our approach. [ABSTRACT FROM AUTHOR]

In this paper, we present a new specific and customized interface tool with parameter identification of Modified Butterworth-Van Dyke models for ladder bulk acoustic wave filters. The aforementioned tool is easy to use and flexible because it allows simulations and reengineering to be conducted in an application. A modular design approach is applied to simplify the extension of the proposed tool for different topologies. The proposed tool was validated using measurements from an aluminumnitride based ladder BAW filter dedicated to the frequency ranges of the Universal Mobile Telecommunications Service and standards and Wideband Code Division Multiple Access. [ABSTRACT FROM AUTHOR]

An RF MEMS zipping analog varactor with a high-permittivity bismuth zinc niobate dielectric has been fabricated and characterized. The varactor can be continuously tuned from 10 to 280 fF, with a very large tuning range of 2700%. By use of gold electrodes to ensure a low series resistance, the high quality factors of 317 and 63 at 1 GHz were measured for the minimum and maximum capacitances, respectively. The self-resonance frequency of the varactor is estimated to be 16.6 GHz at the maximum capacitance and 87.6 GHz at the minimum capacitance. With a small device footprint of 540 \times 130~\mu \textm^2 , the zipping varactor is suitable for application in portable reconfigurable RF systems. [ABSTRACT FROM PUBLISHER]

Radio frequency microelectromechanical system (RF MEMS) switches require a lifetime of 20 years, during which the devices must operate without failure. During operation, the RF MEMS switches are subjected to prolonged actuation which may induce the problems of charge trapping and mechanical relaxation leading to stiction of the moving membrane. In this paper, we suggest an innovative recovery procedure that allows to avoid the stiction. At regular intervals, the switch is opened and an electrical current forced through the suspended membrane can effectively fully recover the switch. Using the topography analysis, we show that the restoring mechanism is based on the recovery of the mechanical properties of the moving bridge during the current flow. The validity of the procedure is demonstrated with the application of the recovery system on several devices for 20 consecutive cycles. [ABSTRACT FROM AUTHOR]

This paper proposes a new analog reflective type phase shifter based on a branch Line coupler (-3 dB, 90°) and radio frequency micro-electromechanical (RF MEMS) capacitive type shunt switch. The proposed scheme is controlled by an applied DC voltage and has the advantage to be compact in the size and having the possibility to operate at high frequencies. The numerical simulation of the designed phase shifter were done by the advanced design system (ADS) software and validated by HFSS; also the mechanical characteristics has been verified using the Comsol software. The obtained results show its performances in the band frequencies between 16.6 GHz and 18.5 GHz with a constant insertion loss less than 0.5 dB, a return loss greater than 30 dB and a linear relative phase shift in the range between -154° to 113°. The use of RF MEMS offers us some compactness with a wide tuning range (η=Cmax/Cmin = 11.88). This proposed phase shifter can be used in different RF applications such as radar beam forming in the operating frequency at 18 GHz. [ABSTRACT FROM AUTHOR]

This paper presents a novel way of controlling the bouncing phenomenon commonly present in the Radio Frequency Microelectromechanical Systems (RF MEMS) switches using a double-electrode configuration. The paper discusses modeling bouncing using both lumped parameter and beam models. The simulations of bouncing and its control are discussed. Comparison between the new proposed method and other available control techniques is also made. The Galerkin method is applied on the beam model accounting for the nonlinear electrostatic force, squeeze film damping, and surface contact effect. The results indicate that it is possible to reduce bouncing and hence beam degradation, by the use of double electrodes. [ABSTRACT FROM AUTHOR]

RF MEMS is a perfect candidate to replace the conventional switches used for microwave frequency. Most of the RF MEMS switches developed generally concentrate on single-pole single-throw based configurations and limited work is reported on switches based on single-pole multiple-throw. This paper reports an RF MEMS single-pole quad-throw (SPQT) switch design and modeling utilizing an axial force coupling mechanism among membranes. The proposed novel SPQT structure consists of twin pair switching membranes coupled using flexible beams. The primary advantage of such a mechanism is to increase isolation as when one switching membrane is pulled down to the ON-state, there develops an axial force on the other and hence it is turned to a better OFF state. The gap on other port increases. Hence, this enables the coupled pair of switches to achieve simultaneously a low actuation voltage, high isolation. The displacement of coupling beams is restricted by a silicon stopper and hence further amplifies the axial force. The designed 3-layer stack (Silicon Nitride/Gold/Silicon Nitride), minimizes the warpage of large membrane. The insertion loss and isolation among throws of the SPQT are simulated to be better than 0.09 and 53 dB at 2 GHz, respectively. The voltage required for actuation is 12 V while the SPQT switch has a compact area of 1 mm × 0.7 mm. [ABSTRACT FROM AUTHOR]

In satellite applications the devices have to retain their functionality for years and this requirement necessitate of reliable methodologies to predict the switch lifetime. At present, a consolidated accelerating test to predict lifetime is still lacking for RF-MEMS devices. The most natural choice of an accelerating factor is temperature. However, MEMS are subjected to both electrical and mechanical degradation mechanisms and temperature has important effects on both. Due to design improvements it is now possible to realize switches where dielectric charging is extremely low and mechanical issues are the dominant mechanisms in the determination of the switch lifetime in long-term actuation experiments. In this paper temperature is used as accelerating factor for the estimation of switch lifetime. The most relevant parameter for failure prediction is the variation of spring constant, which is simply related to the square of the actuation voltage. Based on prolonged actuation measurements at different temperatures on a clamped-clamped ohmic switch, a method to extract lifetime is presented, living in this specific case a failure time of 10 years at 25 °C. Limits and possibilities of this approach are also carefully analyzed. [ABSTRACT FROM AUTHOR]

Thermal cycling tests are an important part of the standard space qualification procedure for RF-MEMS devices. Standardized tests are rather demanding in terms of equipment, sample preparation and experimental time. In this paper, we present a fast thermal cycling test aimed at obtaining a rapid selection among different switch geometries in terms of thermal cycling resistance. Seven different switch typologies are examined and tested, evidencing that the most important source of deterioration is the mechanical deformation of the movable membrane due to changes in internal stresses. For this reason, the clamping typology is the most important design parameter to take into account in order to achieve a good thermal cycling resistance. Contrarily to expectations, the cantilever structure is not the most promising switch typology, because while the main part of the movable membrane is stress free, the anchoring part of the structure is on the contrary heavily stressed and modifies with the temperature change. The most promising structure is a four-anchored switch with a flexural clamping structure that allows the thermal expansions in the horizontal direction, while the data for all the clamped-clamped structures investigated are similar and their differences can be interpreted in terms of different distribution of the thermal strain over the whole membrane. [ABSTRACT FROM AUTHOR]

Shunt capacitive radio-frequency microelectromechanical system (RF MEMS) switches were fabricated on silicon substrate and characterized in the RF domain. Various switch typologies were obtained by three different approaches, which are: (1) the change of the bridge geometric parameters, (2) the covering of the actuator with a floating metal, and (3) the deposition of the bridge directly on the actuator. The S parameters of the fabricated switches were measured in the up and down states, observing the impact on the RF performance of the variation of the geometric parameters and the fabrication process. The electromagnetic modelling of the fabricated switches was used to interpret the measured RF behaviour, allowing to elucidate the drawbacks of the non-perfect conforming of the bridge on the actuator. Finally, the reliability of the fabricated RF MEMS switches under a bipolar voltage excitation was evaluated by cycling tests. Hence, the study presented here provides guidelines to solve some issues of the tight correlation between design, fabrication, performance, and reliability of RF MEMS switches, in view of a large-scale development of these devices. [ABSTRACT FROM AUTHOR]

This paper presents the experimental characterization of the creep effect in electrostatically actuated gold microstructures. The tested specimens follow the typical configuration of the microbridge based radio frequency microelectromechanical systems switches and varactors. Initially, the plastic creep strain accumulation with time is measured for the specimens with different geometric dimensions and at different actuation voltages and temperatures. To avoid the size and cumulative heating effects, three specimens with the same geometric dimensions, actuation voltages and constant temperatures are tested. The test results allowed decoupling the permanent plastic strains due to the creep effect and reversible anelastic strains due to the viscoelastic behavior. The pull-in voltage and natural frequency values measured before and after the creep tests are compared, revealing the mechanical stiffness decrease caused by creep. [ABSTRACT FROM AUTHOR]

CPW (CoPlanar Waveguide) plays major role in design of RF MEMS switch to improve the performance in terms of losses and required bandwidth of operation. This paper proposes the analyses of the mechanical characteristics on the electrical performance of the Capacitive Shunt RF MEMS (CSRM) switch based on various CPW structures and contact area roughness of the switch using electromagnetic 2.5D ADS simulator. The result of momentum method was analyzed up to the K-band frequency of 100 GHz. The result shows that the CSRM switch with two conductor CPW coupler has a maximum isolation of -46 dB with operating bandwidth up to 90 GHz at the resonant frequency of 50 GHz. In order to validate the obtained result, Artificial Neural Network (ANN) has been trained using ADS result. Comparison shows good agreement between ADS and ANN results. [ABSTRACT FROM AUTHOR]

The ITER neutral beam test facility under construction in Padova will host two experimental devices: SPIDER, a 100 kV negative H/D RF beam source, and MITICA, a full scale, 1 MeV deuterium beam injector. SPIDER will start operations in 2016 while MITICA is expected to start during 2019. Both devices feature a beam dump used to stop the produced deuteron beam. Detection of fusion neutrons produced between beam-deuterons and dump-implanted deuterons will be used as a means to resolve the horizontal beam intensity profile. The neutron detection system will be placed right behind the beam dump, as close to the neutron emitting surface as possible thus providing the map of the neutron emission on the beam dump surface. The system uses nGEM neutron detectors. These are Gas Electron Multiplier detectors equipped with a cathode that also serves as neutron–proton converter foil. The cathode is designed to ensure that most of the detected neutrons at a point of the nGEM surface are emitted from the corresponding beamlet footprint (with dimensions of about 40×22 mm 2 ) on the dump front surface. The size of the nGEM detector for SPIDER is 352 mm×200 mm. Several smaller size prototypes have been successfully made in the last years and the experience gained on these detectors has led to the production of the full size detector for SPIDER during 2014. This nGEM has a read-out board made of 256 pads (arranged in a 16×16 matrix) each with a dimension of 22 mm×13 mm. This paper describes the production of this detector and its tests (in terms of beam profile reconstruction capability, uniformity over the active area, gamma rejection capability and time stability) performed on the ROTAX beam-line at the ISIS spallation source (Didcot-UK). [ABSTRACT FROM AUTHOR]

This study presents a 4-bit phase shifter with a maximum phase shift degree of 75° based on packaged metal-contact single-pole double-throw (SPDT) radio frequency microelectromechanical system (RF MEMS) switches mounted on a 20 mil RO4350 substrate and assembled with its driver module on a 4-layer printed circuit board (PCB) board. Electric length of 10° and characteristic impedance of 61.7 Ω are selected for T-stub matching. Standard PCB processing makes it easy to develop and suitable for taking place of mechanical tilt employed in recent base station. Measurements indicate a maximum insertion loss of 1.37 dB at 2.7 GHz and a minimum return loss of 11.71 dB. The phase accuracy is within 1.75° at 2.7 GHz. [ABSTRACT FROM AUTHOR]

The study of long-term reliability of RF-MEMS switches subjected to continuous biasing involves different failure mechanisms: 1) short-to-medium-term stress inducing permanent phenomena, such as permanent mechanical degradation, and 2) long-term stress inducing recoverable phenomena related to mechanical viscoelastic mechanism. The lifetime prediction should consider all the long-term effects after the saturation of all the short-to-medium-term degradation effects. In fact, the lifetime estimation is affected by both the different short-term and long-term degradation mechanisms and not separating the different effects may lead to wrong lifetime prediction. In this paper, we define a preconditioning technique to be applied to each RF-MEMS switch before any stress test. The main purpose is to eliminate all the short-term permanent effects to obtain a lifetime estimation only related to the long-term phenomena. [ABSTRACT FROM PUBLISHER]