Publications by Thomas Maeder | EPFL Graph Search

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This work describes the design, fabrication and laser trimming aspects of a low-cost compressive force sensor with analogue signal conditioning, designed for a medical syringe pump. First, the general design aspects are discussed, in view of facile and reliable batch production and measurement performance. Then, the circuit's trimming procedure is presented, featuring single- pass adjustment of sensor output in its final state, i.e. with all components mounted, without prior passive resistor trimming. Key w

This work introduces and investigates the a novel compact catalytic nanoparticle bed micro-fabricated reactor suitable for utilization in small-scale intermediate-temperature micro-SOFC systems. It is shown that the presented micro-reactor is able to produ ...

In this work we study in more details the impact of voltage trimming on different characteristics of model thick-film resistors (TFRs). Two series of RuO2-based TFRs with different conducting grain sizes are studied. As the composition of model pastes is c ...

Inkjet printing techniques have gained a lot of attention for the micro-structuring of functional materials. This is due to their low cost, low material consumption and relatively easy fabrication process. In this project, Drop-on-Demand (DOD) inkjet printing is used as a means of depositing gas-sensitive polymer nanocomposites on interdigitated electrodes. Different shapes and patterns (e.g. lines and films) can be printed by controlling the coalescence of the neighboring droplets. The final topography of

The intensification of fast exothermic reactions can be achieved by using microstructured reactors (MSR) which provide improved mass & heat transfer rates leading to higher overall reaction kinetics. But for highly exothermic reactions the heat evacuation becomes not efficient enough and unwanted hot spots are formed. In this study, first the mixing in MSR is quantified for different geometries and then temperature profiles are measured using a novel quantitative IR-thermometry method. The results are fitte

In this work, the properties (sheet-resistance, temperature coefficient and piezoresistance / gauge factor) and stability of thick-film resistors with low firing temperatures (525...650°C) are studied. To this end, two low-melting lead borosilicate glass composition have been chosen, together with RuO2 as a conductive filler. The effect on the properties and stability of composition and firing temperature is studied. The stability of the materials is quantified during high-temperature storage (annealing) at

An innovative multifunctional LTCC module has been designed for miniature atomic clock packaging. The components of miniature atomic clocks need to be efficiently packaged and connected to each other, and a precise temperature control is required for them. ...

Simple, low-cost and acid-resistant carbon-based screen-printed electrodes (SPEs) addressed to detection of hexavalent chromium species, Cr(VI), in sulfuric acid at pH about 1, were prepared and characterized. Working and counter electrodes were prepared j ...

Monolithic actuators have turned out to be an efficient solution to several design and assembly problems associated with inertial drive positioning systems. In addition to their compact size with a possible thickness below 1.5 mm, the modular actuators presented in this paper can be manufactured cost efficiently even for small batches. This paper explains the basic operation of the actuators and their fabrication technology based on thick-film technology with assembly on either Al2O3 substrates or PCB. Some

At small sizes, piezoelectric bending actuators are more practical and have more favorable downscaling properties than traditional electromagnets in the field of microfluidics. However, their application is limited by the difficulty of ensuring proper clamping during assembly. Emerging PZT thick-film technologies are promising as they solve the clamping problem, but their performance is still unsatisfactory for most applications. Therefore, the use of bulk PZT benders assembled onto LTCC or alumina by gluin

This reports documents qualification tests made with the 100Ω PTC resistive composition DuPont (DP) 5092D, co-fired on the surface and inside (buried) DP 951 LTCC material, using a wide range of Ag & alloyed Ag-Pd conductor termination: DP 6142D & 6145 (Ag), and 6135D & 6143 & 6146 & 7484 (Ag-Pd). These tests were deemed necessary, as previous ones [1], carried out with Ag terminations only, were deemed not conclusive and reliable enough. The resulting resistors were electrically characterised, and the reli

In this work, mineral sacrificial pastes (MSP) previously developed for standard thick-film technology (alumina substrates) are extended to LTCC in order to make a capacitive anemometer. Application of MSP materials on free-sintering (unconstrained and not zero-shrinkage) LTCC is challenging: shrinkage must be matched to that of the LTCC in order to avoid excessive deformation, or sufficiently compliant materials must be used. Here, different MSP materials / materials systems are described, evaluated and co

But du projet : Dimensionner et réaliser des capteurs de force de l’ordre de 10 à 100 mN nominal Garder l’électronique de traitement du signal et les dimensions de la gamme de capteurs de force existante (MilliNewton du LPM) Utiliser des méthodes de production industrielles ou semi-industrielles qui garantissent un faible coût de production

We show that in RuO2–glass composites the nonuniversal resistivity exponent can be modulated by an applied mechanical strain, signaled by a logarithmic divergence of the piezoresistive response at the percolation threshold. We interpret this phenomenon as being due to a tunneling-distance dependence of the transport exponent, supporting therefore a theory of transport nonuniversality proposed some years ago. © 2004 American Institute of Physics. [DOI: 10.1063/1.1835996]

We fabricated and characterized a micromotor driven by a piezoelectric PZT (PbZrxTi1-xO3) thin films. Sputter and sol-gel techniques have been applied for the deposition of the PZT films onto a silicon stator membrane, which was 20 to 30 µm thick and had a diameter of 4 mm. The amplitudes of the membrane deflections are as large as 800 nm/V at the first resonance (26 kHz), and 60 nm/V at 1 Hz. The operation of the motor was obtained at 1 to 3 Vrms, with speeds of up to 200 rpm at 1.1 Vrms and torques of 35

Les forces de frottement sur la bille de capteurs de force et de déplacement génèrent des moments parasites sur la poutre et entraînent donc des erreurs de mesure. L’erreur relative est potentiellement d’autant plus grande que les coefficients de frottement sont grands, la bille est grande et la poutre est courte. Pour éviter ces erreurs, il faut découpler latéralement le support du capteur et la pièce appliquant la force, en diminuant par exemple la rigidité latérale.

This paper reviews recent developments in integrated fluidic mesosystems, based on low-temperature co-fired ceramic (LTCC) technology, in this laboratory and elsewhere. LTCC is shown to be an advantageous technique for integrated fluidic systems, due to its simplicity, low cost and ease of integration with other technologies and components (silicon, polymer, circuit boards. Also, the techniques utilized in making the structures are presented.

PowerPC Architecture microcontrollers are commonly used in embedded applications. In this work we present FireBird, the first PowerPC based SoC for reliable operation beyond 200C. It is a significant challenge to design SoCs for reliable operation at high ...

The texture of sputter deposited PbTiO3 films could be turned from (100)- to (111)-orientation by adding a few nm thick TiO2 layer onto the textured Pt(111) substrate film. AES, XPS, and XPD measurements showed that such TiO2 films were epitaxially ordered and covered the whole surface of Pt. Various deposition experiments indicated that the TiO2 is effective only when it is ordered before the PbTiO3 nucleation starts. Otherwise, the (100) self texture dominates.

LTCC technology offers low temperature firing (

Thomas Maeder

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Manufacturing and trimming of a low-cost industrial thick-film force sensor

A nanoparticle bed micro-reactor with high syngas yield for moderate temperature micro-scale SOFC power plants

Study of the impact of high-voltage trimming on several characteristics of model TFRs and their stability

DOD Inkjet printing of functional polymers

Characterization of hot spots in microstructured reactors for fast and exothermic reactions in mixing regime

Properties and stability of thick-film resistors with low processing temperatures - effect of composition and processing parameters

Effects of Thermal Losses on the Heating of a Multifunctional LTCC Module for Atomic Clock Packaging

Screen-printed electrochemical chromium (VI) sensing electrodes for effluent bioremediation monitoring

A modular actuator system for miniature positioning systems

Assembly of microvalves actuated by PZT bender

Buried & surface cofiring compatibility of DuPont 5092D PTC thermistor composition with DuPont 951 LTCC

LTCC free-standing structures with mineral sacrificial paste

Capteur de basse force (~10-100 mN) à bas coût de production

Strain modulation of transport criticality in RuO2-based thick-film resistors

Micromachined PZT thin film actuators for micromotors

Erreurs des capteurs de force et de déplacement à poutre dues aux forces de frottement

Integrated microfluidic devices based on low-temperature co-fired ceramic (LTCC) technology

FireBird: PowerPC e200 Based SoC for High Temperature Operation

In-situ sputter deposition of PbTiO3 thin films: nucleation on textured platinum films

Modification of Thick-film Conductors Used in IP Technology for Reduction of Warpage during Co-firing of LTCC (Low Temperature Co-fired Ceramic) Modules