140 research outputs found
A Fully Parameterized Fem Model for Electromagnetic Optimization of an RF Mems Wafer Level Package
In this work, we present a fully parameterized capped transmission line model
for electromagnetic optimization of a wafer level package (WLP) for RF MEMS
applications using the Ansoft HFSS-TM electromagnetic simulator. All the
degrees of freedom (DoF's) in the package fabrication can be modified within
the model in order to optimize for losses and mismatch (capacitive and
inductive couplings) introduced by the cap affecting the MEMS RF behaviour.
Ansoft HFSS-TM was also validated for the simulation of capped RF MEMS devices
by comparison against experimental data. A test run of capped 50 transmission
lines and shorts was fabricated and tested.Comment: Submitted on behalf of EDA Publishing Association
(http://irevues.inist.fr/EDA-Publishing
Coordinating criminal justice: a Qualitative Comparative Analysis of inter-organisational information sharing of four EU Member States
Qualitative-comparative analysis of four cases of inter-organisational information sharing in
criminal justice chains demonstrates the causal asymmetry between successful and
unsuccessful inter-organisational information sharing. While unsuccessful information sharing
requires poor project management, successful information sharing also requires compatible
technologies which are implemented either by means of a small-scale, bottom-up approach to
standardization or a top-down, centralised architecture. By triggering the radical restructuring
of information-sharing workflows, good project management and compatible technologies set
in motion underlying mechanisms that generate successful inter-organisational information
sharing. Implications are discussed by highlighting the role of coordination by technological
feedback in a context of increasing digitization
Digitizing criminal justice: A Qualitative Comparative Analysis of supply-chain integration across four EU Member States
Drawing on Qualitative Comparative Analysis (QCA) techniques, we formally analyse four cases of supply-chain integration within the European Union (EU). Our findings demonstrate the causal asymmetry between successful and unsuccessful digitization of inter-organizational information flows. While unsuccessful digitization requires poor project management skills, successful digitization is much more demanding because it also requires compatible technologies which are implemented either by means of a small-scale, bottom-up approach to standardization or a single, centralised architecture developed in a top-down fashion. Theoretical and practical implications are discussed by highlighting the key role of coordination by feedback in a context of increasing digitization of criminal justice systems
Parasitic Effects Reduction for Wafer-Level Packaging of RF-Mems
In RF-MEMS packaging, next to the protection of movable structures,
optimization of package electrical performance plays a very important role. In
this work, a wafer-level packaging process has been investigated and optimized
in order to minimize electrical parasitic effects. The RF-MEMS package concept
used is based on a wafer-level bonding of a capping silicon substrate to an
RF-MEMS wafer. The capping silicon substrate resistivity, substrate thickness
and the geometry of through-substrate electrical interconnect vias have been
optimized using finite-element electromagnetic simulations (Ansoft HFSS). Test
structures for electrical characterization have been designed and after their
fabrication, measurement results will be compared with simulations.Comment: Submitted on behalf of TIMA Editions
(http://irevues.inist.fr/tima-editions
Macromodel-based simulation and measurement of the dynamic pull-in of viscously damped RF-MEMS switches
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Low-temperature thin film encapsulation for MEMS with silicon nitride/chromium cap
In this work, a low-temperature fabrication process of thin film encapsulation (TFE) with silicon nitride/chromium cap is proposed for large-size (750 μm x 300 μm) packaging of microelectromechanical systems (MEMS). A FEM model was developed to evaluate the shape of TFE as a function of the residual stress and the thickness of the sealing layer, providing useful guidelines for the fabrication process. The low temperature of 200 °C, which was used in the plasma-enhanced chemical vapor deposition of the silicon nitride capping layer, allowed an organic sacrificial material to be employed for the definition of the encapsulation area. Silicon nitride/chromium (1 μm/20 nm) bilayer was demonstrated to be successful to overcome the technological limitations that affect the creation of cap holes with size of ~2 μm on high topography substrates, as in the case of MEMS. Plasma focused ion beam (PFIB) and scanning electron microscopy (SEM) techniques were used in combination to gain deeper insight into the sealing process of cap holes. Specifically, a PFIB-SEM serial section procedure was developed, resulting to be a powerful tool to directly observe the sealing profile above cap holes. Hence, the presented results greatly contribute to overcome the main technological/reliability issues of TFE, paving the way for the widespread application of the proposed encapsulation methodology to the most used MEMS devices, as radio-frequency (RF) switches, transducers, actuators, sensors and resonators
Energetic analysis and optimal design of a CHP plant in a frozen food processing factory through a dynamical simulation model
The proper design of cogeneration plants requires the choice of the technologies that best fits the ratio between heating and power loads. In this paper, a dynamical procedure of selecting and dimensioning a cogeneration plant, using deep and detailed energy, exergy and economic analysis of the entire production process of a frozen food production factory is proposed. The results highlight that a design method, based on a dynamic simulation, optimizes the energy efficiency of the food processing plant involved in the experimental test. Indeed, by considering the overall efficiency of the CHP + National grid system, the energy efficiency is 6% higher in the case of dynamic compared to a static design, resulting in better overall use of resources with a possible lower level of environmental impact. Moreover, the CHP plant designed with the proposed method generates electrical energy which appropriately matches that required by the process, with a surplus/deficit less than 4%, while the classic method never covers the amount required and results in a deficit greater than 20%. Finally, the annual savings of the solution derived from the dynamic method is 12% higher than that obtained with a traditional design technique. Considering the greater absolute cost of the cogeneration plant, this dynamic approach results in more profitable annual investment margins for the company
Experimental investigation on the exploitation of an active mechanism to restore the operability of malfunctioning RF-MEMS switches
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Le sentinelle dei prati: dal BeeOdiversity Park di Montebello di Bertona un progetto per la salvaguardia degli apoidei
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