17 research outputs found
Computed tomography colonography imaging of pneumatosis intestinalis after hyperbaric oxygen therapy: a case report
Global model generation for a capacitive silicon accelerometer by finite- element analysis
A method to evaluate capacitance based on parameter extraction from finite- element analysis as well as a global model for a novel silicon microfabricated accelerometer are presented. Mechanical simulations have been performed and results are coupled with the capacitance-evaluation method to compute the static and dynamic response of the accelerometer. Using both mechanical data and capacitance data, a global model for the accelerometer is generated with models written in Hardware Description Language for Analogue device (HDL- A(TM)). An improvement of the capacitive displacement detection technique is obtained. (C) 1998 Elsevier Science S.A. All rights reserved
Micro-accéléromètre intégré 3 axes
ISBN: 2-7462-0142-9Cette revue s'adresse à l'ensemble de la communauté scientifique et technique des chercheurs et des ingénieurs en nanotechnologies, microtechnologies, miniaturisation et intégration des microsystèmes
A RF tunable Agile Filter: From component to system design
International audienceThe work is related to an Agile Filter which is a specific RF block to be inserted between an antenna and a first stage of pre-amplification in future on board antenna systems or any future multi-purpose communications terminals. It will be able to process signals in the frequency range between 2 and 18 GHz with target insertion loss below 3dB. The basic idea of the demonstrator studied and developed in this project is to evaluate a SiP approach combining heterogeneous technologies and 3D integration and packaging. This paper presents the process flow used to design, fabricate and integrate in 3D a tunable RF filter which tunability is obtained by the use of MEMS varactors based on a copper on glass technology and stacked on micro-PCD for the electronic control functions. MEMS+ parameterized structures for RF MEMS varactor designs are presented with dimension constraints to be compatible with the space available at the end of each combline sub-filter. Indeed, the MEMS capacitors are composed of a mobile square membrane of 210μm by side and overall size of 600μm. In addition, these RF MEMS tunable capacitor models were automatically transferred into VerilogA for rapid system-level simulation usable further in ADS environment to verify the RF performances
Design of freeform geometries in a MEMS accelerometer with a mechanical motion preamplifier based on a genetic algorithm
This paper describes a novel, semiautomated design methodology based on a genetic algorithm (GA) using freeform geometries for microelectromechanical systems (MEMS) devices. The proposed method can design MEMS devices comprising freeform geometries and optimize such MEMS devices to provide high sensitivity, large bandwidth, and large fabrication tolerances. The proposed method does not require much computation time or memory. The use of freeform geometries allows more degrees of freedom in the design process, improving the diversity and performance of MEMS devices. A MEMS accelerometer comprising a mechanical motion amplifier is presented to demonstrate the effectiveness of the design approach. Experimental results show an improvement in the product of sensitivity and bandwidth by 100% and a sensitivity improvement by 141% compared to the case of a device designed with conventional orthogonal shapes. Furthermore, excellent immunities to fabrication tolerance and parameter mismatch are achieved. © 2020, The Author(s)
Simulation and design of a three axis navigation microsystem based on micromachined sensors
The project presented in this paper aims at defining the limits of microsystems through the realisation of a navigation system based on inertial microsensors. The work includes (i) design, fabrication, characterisation of accelerometers and angular rate sensors, (ii) development of techniques for simulation of sensor behaviour, and (iii) design of a sensor data processing system
3-D scanning of sea freight containers using MeV X-rays
The ECSIT project analyses how innovative inspection technologies can lead to an enhanced container security and how these technologies can be embedded into a holistic concept. It has the goal to analyze the possibility and feasibility for 100% scanning of all containers which are shipped to US ports and to develop a concept for integrating necessary infrastructure. A key element of the entire concept is the scanning technology itself. MeV X-ray technology using a linear accelerator as radiation source provides the feasibility to visualize the content of a container without opening it. If a 2-D radiography is ambiguous, a 3-D evaluation of the respective location could be conducted. MeV X-ray computed tomography (CT) is such a method to provide 3-D information of the content of a container. In the context of ECSIT, Fraunhofer EZRT has developed the concept of such a continuative high energy X-ray scanning stage and evaluated its application to sea freight containers. In this paper different approaches for measuring a 3-D tomographic volume data set of objects which are very heavy and thus difficult to move in arbitrary directions will be discussed. Three different geometrical principles for data acquisition were evaluated: laminography, limited angle CT, and a gantry CT. The volume data sets were reconstructed by using a standard filtered back projection and different algebraic reconstruction techniques (ART). Real 3-D volume data of large objects measured with the set-up described above are presented. As test objects a real container packed with various typical goods like furniture or consumer electronics as well as simulated threats like a bomb mock-up was used