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A high-linearity 5.3-7.0 GHz three-pole tunable bandpass filters has been developed. Three half-wavelength resonators loaded with commercial RF MEMS capacitors are used in a sequential configuration to implement a compact tunable filter. All the inter-stage couplings are inductive type, and input and output matching networks are achieved using shunt inductors. The measured insertion loss and 1-dB fractional bandwidth are less than 5.3 dB and 510–620 MHz, respectively. The measured IIP3 is greater than 45 dBm at all tuning frequencies. The application areas are for high-linearity communication systems at C-band and IF tunable bandpass filters.

The validity and applicability of a high-level simulation approach of radio-frequency microelectromechanical system (RF-MEMS) devices, based on a library of analytical compact models of elementary MEMS components, are investigated through an extensive comparison between simulation results and measurements of some representative devices (variable capacitors and series ohmic switches). The in-house developed simulation tool is implemented in a standard IC simulation environment supporting behavioral description capabilities. The devices are built in a silicon substrate technology with suspended gold membranes. We analyze the mechanical, electrical, and RF response of the devices. The RF behavior is modeled by extracting a lumped element network from measured S- parameters (scattering-parameters) to account for parasitic effects and by wrapping this network around the intrinsic MEMS device simulated with the compact models. We show that an accuracy within 5% is obtained in all considered physical domains and conditions, provided that some effective parameters (including the residual air gap in the actuated state and the RF parasitic elements) are properly extracted from measurements and accounted for in the simulations. The main factors limiting the model’s predictive capability are due to process nonidealities, such as plate bending due to residual stress gradient, oxide charging, surface roughness, and suspended membrane thickness variations, rather than for instance in-plane geometric process variations.

In this paper, development of a wafer-level packaging (WLP) process suitable for RF–MEMS applications is presented. The packaging concept is based on a high-resistivity silicon capping substrate that is wafer-level bonded to an RF–MEMS device wafer providing MEMS device protection and vertical electrical signal interconnect. The capping substrate contains Cu-plated through-wafer electrical vias and optional through-substrate cavities allowing for hybrid integration. The RF–MEMS device wafer and the capping substrate are bonded using either solder reflow or an electrically conductive adhesive. After solder bump formation and singulation, this packaging solution results in surface-mount technology compatible components. Moreover, the presented WLP solution allows hybrid integration of additional IC dies that are flip-chip bonded within the capping substrate cavities.

This paper presents the first RF MEMS VCO at 1–1.2 GHz with no measured mechanical resonances in its close-in frequency response. The oscillator results in output power of 2.5–4.5 dBm at 1–1.2 GHz and a best phase noise of −152 dBc/Hz at 10 MHz offset. A low-level spurious is seen at 131 kHz and its harmonics of 262 kHz due to the internal charge pump. The application areas are in high performance 0.5–3 GHz oscillators requiring varactor Q of 100–200.

In this paper, we present a new type of rf MEMS switch with low actuation voltage and high isolation, for high rf power and reliability applications in telecommunication. ‘Symmetric toggle switch’ (STS) is based on push–pull mechanism and utilizes torsion springs and levers, placed symmetrically and transverse to CPW line. The switches designed for 8–14 GHz applications have analytically calculated and FEM simulated actuation voltages in the range of 8–10 V. The simulated insertion loss and isolation for the devices are 0.25 and 35 dB, respectively, at 10 GHz. The fabrication process and preliminary experimental results are also presented.

In this work, we present electromagnetic optimization of a wafer-level package (WLP) intended for RF-MEMS applications. The packaging solution presented is based on a high-resistivity silicon capping substrate containing recesses and copper-filled thru-hole vias. This pre-fabricated capping substrate is first wafer-level bonded to the RF-MEMS device wafer, then populated by solder spheres and finally singulated into individual packages. For the package electrical optimization, Ansoft HFSS electromagnetic simulator has been used in order to assess the RF-behaviour of packaged MEMS devices, including losses and mismatch due to inductive and capacitive couplings introduced by the cap. A fully parameterized model of a 50 Ohm coplanar waveguide (CPW) including all the degrees of freedom (DoFs) made available by the technological process is presented and extensively exploited for the electromagnetic optimization of the capping structure. Moreover, the measurement data obtained from the fabricated capped and uncapped test structures (50 Ohm CPWs and shorts) and their comparison with simulations are presented.

A measurement system combining vector corrected waveform measurements with active harmonic load-pull extends, for the first time, real-time experimental waveform engineering up to the 30-W power level. The vector correction procedure is presented in this paper. A novel harmonic load-pull approach based on the real-time measurement capability of the system is demonstrated on a 4-W LDMOS device. A 20% increase in maximum output power to 4.7 W without degrading gain and efficiency is realized. Waveform analysis at various drive and load conditions directly identifies nonlinear capacitance effects being a key design issue for the design of highly efficient power amplifier.

We propose a nonlinear model of a resistive MEMS switch. We describe the nonlinear behaviour of the switch by exploiting an extended harmonic balance (HB) technique allowing the efficient calculation of distortion effects due to MEMS nonlinearities. A comparison with the corresponding capacitive model is also given. As an illustrative example, the results of the simulation of a reconfigurable integrated antenna operated by commercial MEMS switches are compared to measurements.

Electrostatic actuated radio frequency microelectromechanical systems (RF-MEMS) switches and variable capacitors are susceptible to issues related to RF actuation or even RF pull-in under large-signal regime. This phenomenon is strictly related to the average RF voltage more than power, and the impedance environment of the device should be fully accounted for. We perform for the first time large-signal time-domain measurements to characterize the RF actuation effect on the real-time capacitance value of a suspended membrane-based RF-MEMS varactor, while controlling the load impedance presented to the device with an active load-pull. The dependence of RF-actuation on both real impedance and inductive admittance is directly extracted, giving strong insights on how power handling should be carefully scrutinized against each specific circuit design.

A simulation methodology to reduce computational time of pre-stressed harmonic analysis of radio frequency (RF) microresonators is demonstrated. The methodology is based on the application of model order reduction to a system of ordinary differential equations obtained after spatial discretization by finite element software. Model order reduction produces a low dimensional approximation of the original system and hence enables a substantial reduction of simulation time while maintaining a very small approximation error. The approach allows to perform rapid device design and optimization. Once the device design and working conditions have been defined its reduced model can also be used to implement a behavioural model that can be employed in system level simulations.

RF-MEMS switches have potential prerogatives better than traditional solid state devices, but the presence of mechanical movement introduces new classes of reliability issues that are not found in traditional devices. In this work we have carried out an extensive electrical characterization in order to identify the dynamic response of RF-MEMS switches driven in different conditions of voltage and actuation time. Furthermore, probably due to their recent introduction to the market, the robustness of MEMS submitted to ESD stresses has been also poorly investigated. We have studied, for the first time to our knowledge, the effects of TLP-ESD events on RF-MEMS switches identifying a very critical ESD sensitivity.

This paper presents a 1.5-2.4 GHz 4-pole tunable filter using the Cavendish Kinetics RF MEMS capacitors. The MEMS capacitors are fabricated and fully packaged using a 0.18 μm CMOS standard process with integrated high voltage drivers and SPI control logic and with reliability in the billions of cycles. The filter results in a power handling of at least 20 dBm, a second and third harmonic generation of

Industrial design constraints coupled with increased frequency coverage required for today's mobile Smart Phone handsets, are making it difficult to develop highly efficient broadband antenna solutions. This paper will show how antenna aperture tuning using a high performance MEMS (microelectromechanical system) Digital Variable Capacitor can improve antenna performance across all frequency bands for 3G and 4G LTE communications.

In this letter, we correlate different breakdown mechanisms occurring near pinch-off and in off-state conditions in power AlGaAs/GaAs heterojunction FETs (HFETs), operated in "three terminals" (on-state) and "two-terminals" (off-state) modes, to electroluminescence emission due to high energy carriers, electrons, and holes. In particular we will use spectral analysis and spatially resolved emission analysis in order to identify regions of the device where hot and cold carriers emit light. We will show how under "three-terminals" breakdown conditions high energy carriers emit light at the drain side of the gate while cold carriers recombine mostly at the source side of the gate.

In this paper we discuss an approach for the implementation of non-linear electromechanical and RF models of complete RF-MEMS devices within a standard circuit simulator, such as Cadence Spectrecopy or Agilent ADStrade. The intrinsic electromechanical core is based on a structural hierarchical model library implemented in VerilogAcopy language. Moreover, a surrounding lumped element network accounting for the electromagnetic RF behaviour of the MEMS device is extracted from S-parameters measured data. The whole nonlinear model network, composed of the intrinsic VerilogAcopy core plus lumped-element parasitics, can be analysed within a radiofrequency circuit simulator schematic. The model is fully validated against electromechanical and RF static and dynamic measurements, showing good agreement between simulations and experimental results. The presented modeling approach can be the basis for the development of complete RF-MEMS design technology libraries, aiming at optimum hierarchical designs of MEMS-enabled RF circuit blocks.

In this work, a new method is presented for the extraction of low order electromechanical models for dynamic nonlinear simulation of radio frequency (RF) microelectromechanical (MEMS) switches, using model order reduction (MOR). The method is based on a separate modeling of the electrical and the mechanical part of the problem, which are coupled at circuit level. The derived reduced order model includes effects of initial stress in the device materials and enables a substantial speed-up of large signal dynamical analysis. The accuracy of the model has been demonstrated by comparing the simulated and measured dynamic response of a fabricated device.

A wide frequency span reconfigurable MEMS-enabled LC-tank network for a multi-band RF oscillator is implemented, made of ohmic RF-MEMS switches, spiral suspended inductors and metal-insulator-metal (MIM) capacitors all integrated on a high resistivity silicon MEMS substrate. The LC-tank is connected to a differential cross-coupled n-MOS pair on a separate CMOS substrate, by chip-on-chip integration and wire bonding, leading to the complete MEMS-CMOS oscillator prototype. The separate LC-tank and the complete oscillator are both tested on-wafer through RF-probing. Measurement results show two resonance frequencies of 1.375 GHz (Q = 7.2) and 3.605 GHz (Q = 14.4) for the MEMS-enabled LC-tank. The MEMS-CMOS oscillator shows a phase noise of -124.5 dBc at 1MHz frequency offset, with 3mA bias current at 1.2 V power supply. Overall oscillator performances well compare with state-of-the-art non-reconfigurable CMOS oscillator designs.

A hierarchical and mixed-domain design approach is implemented within the Cadence/sup /spl reg// simulation framework and applied to an integrated MEMS-CMOS oscillator. Parameters concerning both the electronic circuit description at transistor level and the MEMS structure defined by its topology and dimensions, are available during simulation. This approach can lead to a full optimisation of the complete MEMS-CMOS sub-system, with a view to both electrical and mechanical specifications.

A hierarchical MEMS design library, implemented in SpectreHDL/spl reg/ within the Cadence/spl reg/ simulation framework is applied to the study of distortion phenomena in RF-MEMS capacitive shunt switches. Two-tone mixed-domain transient simulation of the non-actuated switch, operated at high-power, directly shows, for the first time, self-biasing modulation at the tones spacing frequency. Adjacent-channel intermodulation products are observed and quantified, proving that the adopted mixed-domain simulation approach is the key tool for addressing system-level specifications in RF-MEMS design for wireless applications.

Here we approach for the first time the problem of hydrogen poisoning for Al/Ti-gate (Pt-free) AlGaAs/GaAs power HFETs. Throughout the stress, we have monitored the changes of I/sub DSS/, g/sub m/, threshold voltage (V/sub T/) and gate barrier height (/spl Phi//sub B/) The separate measurement of the shifts of V/sub T/ and /spl Phi//sub B/ allows us to gain new insight of the mechanisms underlying the device changes during hydrogen exposure. Moreover, by measuring the source-gate and drain-gate breakdown voltages, as well as the g/sub m/ frequency dispersion, we can speculate on the effect of hydrogenation on the access regions on the gate sides.

Analytical nonlinear model validation through large-signal time-domain characterization has been greatly improved, by establishing a novel link between measurement and simulation. Investigation on a silicon LDMOS device and its nonlinear electro-thermal model positively identifies links between model formulation and amplifier requirements for future telecommunication systems.

Compression and harmonic generation mechanisms coupled to the non-linear output drift-region capacitance of Silicon LDMOS FET transistors are thoroughly investigated. Large-signal time-domain analysis is performed on the device operated as a class AB amplifier. Observations confirm significant real power being shifted from the fundamental to the even order harmonics by the capacitive element acting effectively as a varactor diode multiplier.

A measurement system combining vector corrected waveform measurements with active harmonic load-pull extends, for the first time, real-time experimental waveform engineering up to the 30 W power level. This novel harmonic load-pull approach is demonstrated on a 4 W LDMOS device. A 20% increase in maximum output power to 4.7 W without degrading gain and efficiency was realized.

A MEMS (microelectromechanical system) test structure for planar stress characterization of the structural layer in a surface micromachining process is presented. The classical rotating needle design has been adopted and enhanced with electrical capacitive transduction of the rotation angle. The main goal is a device suitable for electrical measurements in order to allow in situ and fast in-line automatic testing. Stress extraction is performed through quantized capacitive transduction, leading to improved robustness versus capacitive parasitic effects which typically impair the analog transduction. The methodology is demonstrated through a comparison between electrical measurements and optical inspections on fabricated prototypes based on a gold electroplated structural layer.

A small signal parameter extraction procedure is presented suitable for power LDMOSFET devices for radio frequency applications. Small signal measurements on the nonconducting device, i.e. biased in off-state, are manipulated analytically in one single extraction step. The parasitic series resistances and inductances and the device intrinsic capacitances at varying biasing voltages are obtained.

This work describes results of hydrogen degradation experiments performed on Al/Ti-gate AlGaAs-GaAs power HFETs. Upon storage at 180/spl deg/C for times up to a hundred hours in either 5% or 15% H/sub 2/-N/sub 2/ mixtures, the HFETs undergo significant changes in their electrical characteristics due to mechanisms located either under the gate (bulk effects) or on the surface access regions on the gate sides (surface effects). The former lead to a threshold voltage reduction and thus to an increase in the drain current, attributed to TiH formation in the gate and the attendant piezoelectric charge in the underlying semiconductor; a degradation of the peak transconductance is also observed. As for the surface effects, we measure an increase of source-gate and drain-gate breakdown voltages, due to surface-state creation on the gate sides and to electron capture therein.

This paper presents wafer-level packaging (WLP) solution for RF-MEMS applications based on through-wafer via (TWV) technology in high-resistivity silicon (HRS). A pre-processed HRS capping wafer containing recesses and vertical Cu-plated TWV interconnect is, after alignment, bonded to the RF-MEMS wafer providing environmental protection and easy signal access. Optionally, cavities can be formed simultaneously with TWV in the capping wafer, which allows hybrid co-integration of additional IC dies while maintaining overall thickness of the resulting SMT compatible package. This cavity can also be used for a first-level wafer-to-wafer alignment accuracy check. After bonding, the s-parameter measurement at giga hertz level shows little influence introduced by the capping substrate.

A hierarchical MEMS design library, implemented in SpectreHDL® within the Cadence® simulation framework, is applied to the study of distortion phenomen in RF-MEMS capacitive shunt switches. Two-tone mixeddomain transient simulation of the non-actuated switch, operated at high-power, directly shows, for the first time, self-biasing modulation at the tones spacing frequency. Adjacent-channel intermodulation products are observed and quantified, proving that the adopted mixed-domain simulation approach is the key tool for addressing system-level specifications in RF-MEMS design for wireless applications.

In&Out is a project that comes from the idea of underlining the strong relationship between lining and tailoring, and through this, the one between industrial production and manufacturing. In the field of fashion, the design of a detail can lead to a consistent and recognisable visual identity system that characterises the project. Through the collaboration between the Fashion Advanced Design Studio of Politecnico di Milano and the lining leading players, seven capsule collections with different graphic patterns of tailored men’s jackets are born, experimenting a new vision of the traditional lining.

Questo lavoro esamina, attraverso la lettura di materiali inediti reperiti negli archivi italiani, la storia di una significativa azienda della storia della moda italiana, la Mario Valentino, nata nel cuore di Napoli negli anni Cinquanta come impresa calzaturiera e progressivamente cresciuta, fino a divenire negli anni Settanta e Ottanta uno dei marchi leader nel settore della pelle. Internazionalizzata rapidamente grazie al coinvolgimento di noti stilisti e autorevoli artisti ha esteso il suo ambito produttivo dalla scarpa di alta qualità all’abbigliamento di lusso.

The paper aims to describe the design tools for the enhancement of territorial capital through a case history that experiments a creative process, shared with different actors, for the development of new products in the cosmetic field. The design is able to activate strategic actions, to enhance the know-how, to optimize the knowledge networks and create sharing processes that enable the development of complex scenarios to configure new goods and services. The methodology used has developed a creative ecosystem where multidisciplinary skills have given rise to a constructive dialogue to lead all the phases of the design process. The paper reports the case study Helementa case study: thermal cosmetic products. A draft design for cosmetics, in which the design is the tool for the exalt of the territorial capital and the activator of sharing and know-how exchange dynamics.

We propose the design of a reconfigurable impedance matching network for the lower RF frequency band, based on a developed RF-MEMS technology. The circuit is composed of RF-MEMS ohmic relays, metal-insulator-metal (MIM) capacitors and suspended spiral inductors, all integrated on a high resistivity Silicon substrate. The presented circuit is well-suited for all applications requiring adaptive impedance matching between two in principle unknown cascaded RF-circuits. The fabrication and testing of a monolithic integrated prototype in RF-MEMS technology from ITC-irst is currently underway., Comment: Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/EDA-Publishing)

Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/handle/2042/5920); International audience; The air-gap and dielectric thicknesses are key technology parameters of a micromachining fabrication process; their correct estimation is necessary for both good prediction of MEMS devices behavior and process monitoring. In this paper we present a methodology for their accurate quantification making use of capacitive test-structures, in order to allow automated data-extraction or, in general, capacitance measurements with standard lab instrumentation; the parameters are computed from measurements through a simple analytical model. Model validation and robustness to main parameters deviations and undesired mechanical effects are investigated by finite element analysis using CoventorWare_.

The continuously evolving MEMS technology for RF/microwave applications poses issues regarding new reliability and lifetime estimation. We will overview the most important degradation mechanisms concerning capacitive and ohmic RF-MEMS devices and their effects on the device lifetime. Preliminary results will also be given on ElectroStatic Discharge effects on ohmic shunt switches adopting a Transmission Line Pulse stress technique.