Laboratoire d’analyse et d’architecture des systèmes
C.ARENAS BUENDIA, J.PHILIPPE, D.HENRY, A.RUMEAU, H.AUBERT, P.PONS
Manifestation avec acte : European Microwave Week ( EuMW ) 2017 du 08 octobre au 13 octobre 2017, Nuremberg (Allemagne), Octobre 2017, 5p. , N° 17268
This communication reports the first experimental results obtained from new type of passive Hydrogen-Pressure Dosimeters for the remote measurement of nuclear radiation. Technological and experimental analyses are performed here to demonstrate the proof-of-concept. Radar measurements of irradiated and non-irradiated passive dosimeters are also reported and confirm the feasibility of the remote reading of such passive sensors. A new design is proposed for minimizing the impact of technological inaccuracies on sensors performances and for facilitating the packaging.
H.AUBERT, D.HENRY, P.PONS
Conférence invitée : IEEE Nanotechnology Materials and Devices Conference ( IEEE NMDC ) 2017 du 02 octobre au 04 octobre 2017, Singapour (Singapour), Octobre 2017, 1p. , N° 17344
The remote measurement of physical or chemical quantities from the wireless reading of active electronic devices with integrated sensors is no more a major issue. Such devices with sensing, identification and communication capabilities can be used as nodes of a network and, more generally, part of the Internet of Things. Passive (batteryless) sensors could be used as sensing nodes in order to ensure unlimited energy autonomy, long-term measurement stability, low-cost of fabrication and operability in harsh or severe environments. However the interrogation range achievable by passive RFID sensors does not exceed 20 meters in harsh and/or highly reflective environments. An alternative solution to RFID sensors technology will be presented at the conference. It consists of applying an active millimeter-wave radar imaging technique to the detection and long-range reading of passive sensors. The use of millimeter-waves frequency for the wireless interrogation of sensors rather than lower frequency offers many advantages, such as, higher electrical length separation distances to objects located around the sensors, higher robustness to multi-paths, smaller sensors and reader antenna sizes, higher frequency bandwidth and compact design for beamforming, multi-beam or beam-steering Radar reader. The first part of the presentation will be devoted to the technology used by the authors and his collaborators at LAAS-CNRS, Toulouse, France, for fabricating miniaturized millimeter-wave passive sensors. Some recent sensors based on MEMS, microfluidic and/or ink-jet printing technologies will be presented. Next an active radar imaging technique will be reported for the long-range reading (up to 50 meters) of these passive millimeter-wave sensors. It consists of performing the beam scanning of the radar main lobe and/or translating the radar for illuminating the scene incorporating the sensors at different angles in order to obtain a 3D radar image. Statistical estimators are then computed from this image for remotely deriving the physical quantity of interest. Very recent results will be reported and discussed at the conference. The technical challenges and possible solutions regarding the fabrication of miniaturized and wireless passive sensors will also be presented.
I.PASQUET, H.LE TRONG, V.BACO-CARLES, L.PRESMANES, C.BONNINGUE, V.BAYLAC, P.TAILHADES, V.CONEDERA, P.F.CALMON, D.DRAGOMIRESCU, H.CAMON
CIRIMAT, TEAM, MINC, PHOTO
Revue Scientifique : Journal of the European Ceramic Society, 17p., Septembre 2017, https://doi.org/10.1016/j.jeurceramsoc.2017.03.030 , N° 17162
Films of copper and cobalt-iron oxalates were prepared from suspensions of powders in ethane-1,2-diol deposited on glass or polycarbonate substrates. Two-dimensional structures of oxides, resolved on the scale of less than ten micrometers, were formed by laser insolation of these films, using a photolithography machine. The nature of the constitutive phases of the oxides formed tends to show that the laser heating makes it possible to reach locally, temperatures higher than 1000 °C. The oxides formed are thus sintered. The residual oxalate can be removed by washing or dissolving, leaving the oxide structure on its substrate. In spite of a perfectible sintering, the formed structures could interest different technological applications (electronic or magnetic devices, gas sensors, photovoltaic systems…) requiring the shaping of simple or mixed oxides on a scale close to the micrometer. The process of selective laser decomposition of oxalates, could subsequently be suitable for additive manufacturing of 3D parts.
S.CHARLOT, P.PONS, M.DILHAN, I.VALLET, S.BRIDA
TEAM, MINC, Esterline Sensor Gpe
Manifestation avec acte : Eurosensors 2017 du 03 septembre au 06 septembre 2017, Paris (France), Septembre 2017, 2p. , N° 17266
This paper presents the study of gold/gold thermocompression bonding at silicon wafer level. The first samples contains sealing rings and electrical pads and are characterized on pull and shear test showing bond strength similar to silicon/glass anodic bonding (10MPa-80MPa). A sealed cavity and a piezoresistor on a 30µm-thick silicon membrane are added in the second samples. Helium test, membrane deflection and piezoresistor signal monitoring after aging 14 days at 250°C confirm the vacuum stability inside the cavity after bonding. Motivation and results Several bonding techniques [1-5] exist to ensure hermeticity and protection of sensor inside micro-cavities. The analysis of gold thermo-compression bonding performed here contains both sealing ring and electrical contacts. To qualify our process, two different structures are realized to test bond strength (Figure 1) and hermeticity (Figure 2). For both structures, two 4 inches 500µm-thick, double-sided polished silicon wafers with 200nm-thick thermal SiO2 are used. On each wafer, a diffusion barrier followed by 50nm/500 nm Ti/Au evaporated seed layer is deposited. Then a 3µm-thick electroplating gold is deposited inside a patterned resin mold in order to define sealing rings and electrical pads. For the second structure, a square membrane (30µm-thick and 2000µm-side) and piezoresistors are added. For both structures, we used a SUSS-SB6 bonder to perform the thermocompression bonding (420°C, 5,7MPa, 50 minutes). We include spacers between the wafers during alignment to obtain vacuum inside the cavity (5.10-3 mbar). After bonding and dicing, some dies are polished to observe the gold structure at the interface (Figure 3). No delamination is observed between the different materials showing a complete atomic diffusion at the gold interface bonding. Batches of 20 dies are then selected from different wafer areas for pull and shear tests. Most of the dies exhibit cohesive fracture in silicon with tensile strength comparable or superior to silicon/glass anodic bonding (figure 4). Even if pull tests are often used for the qualification of bond strength, this technique don't give reproducible results compared to shear test. High rate leakage through bonding interface has been evaluated with structure 2 by monitoring the membrane deflection several hours after bonding with a mechanical profiler. Measurements show deflection between 4µm and 5µm for 75% of the cells, which is consistent with simulation and technological process variations. In order to check more precisely the leakage, the dies (after breaking the thin silicon membrane) are glued on a special tool where one side of the die is exposed to He and the other side is connected to vacuum (1.10-9 mbar) detector equipment (Figure 5). The mean leak measured by He detector was 10-8 mbar.l/s for the best dies structure bonded which correspond to an excellent hermeticity. The hermeticity reliability has been characterized by following the response of a piezoresistor placed on the membrane after aging at 250°C during 14 days for 6 cells (Figure 6). The piezoreristance shift is lower than 250 ppm for the best cell which correspond to a 75mbar variation inside the cavity.
J.PHILIPPE, C.ARENAS BUENDIA, D.HENRY, A.COUSTOU, A.RUMEAU, H.AUBERT, P.PONS
Manifestation avec acte : Eurosensors 2017 du 03 septembre au 06 septembre 2017, Paris (France), Septembre 2017, 3p. , N° 17264
A new millimetre-wave passive and chipless packaged sensor for wireless pressure monitoring in harsh environment is proposed. This sensor uses a planar microstrip resonator coupled with a high resistivity silicon membrane. The remote interrogation of this sensor is performed from a Frequency-Modulated Continuous-Wave (FMCW) radar. Prototypes have been designed and fabricated using photoresist intermediate layer for the silicon membrane bonding. Radar measurements on two sensors validate a 6dB full-scale response for 1.4 bar overpressure. Depression measurements demonstrate the transducer hermeticity and a measured sensitivity of 1.6% per bar on the millimetre-wave resonant frequency.
J.RIONDET, A.COUSTOU, H.AUBERT, P.PONS, M.LAVAYSSIERE, J.LUC, A.LEFRANCOIS
MINC, I2C, CEA-DAM
Manifestation avec acte : Micromechanics and Microsystems Europe workshop ( MME ) 2017 du 23 août au 25 août 2017, Uppsala (Suède), Août 2017, 6p. , N° 17265
Available commercial piezoelectric pressure sensors are not able to accurately reproduce the ultra-fast transient pressure occurring during an air blast experiment. In this communication a new pressure sensor prototype based on a miniature silicon membrane and piezoresistive gauges is reported for significantly improving the performances in terms of time response. Simulation results indicate that it is possible to design a pressure transducer having a fundamental resonant frequency almost ten times greater than the commercial piezoelectric sensors one. 1. Introduction The typical pressure over time during an explosion is shown in Figure 1 [1-2]. First of all, the pressure increases abruptly (with a rise time between 10 ns and 100 ns) from atmospheric pressure to reach the overpressure peak Pmax (several tens of bar depending on the explosive load and the distance from the load). Then the pressure returns back to the atmospheric pressure during a positive phase in 500 µs followed by a negative phase. In order to validate the hydrocode, i.e. numerical simulations describing the shockwave discontinuity, an accurate measurement of the overpressure peak Pmax is required , involving the use of pressure sensors presenting a short time response (<< 1µs). Moreover, the high temperature environment during the explosion (> 1000 °C) makes the real-time dynamic pressure measurement of the blast very challenging. The sensors used for the dynamic measurement of the pressure in harsh environment are usually piezoelectric pressure sensors (Table 1). Air blast experiments were performed at CEA-Gramat center using many piezoelectric sensors mounted on pencil probes to measure the incident pressure, ie with sensor surface parallel to the shock wave propagation (Figure 2). A typical example of the response of such sensors is illustrated in Figure 3. It can be observed that the time response is too long to provide an accurate estimation of the overpressure peak Pmax. The high cutoff frequency of such sensors is approximately 20 % of the resonant frequency. This bandwidth is also degraded by the large dimensions of the sensing part (between 78 mm² and 450 mm²). Moreover typical piezoelectric sensors have a low cutoff frequency (> 0.5 Hz at-5 %) which is too high to follow the overpressure decrease. The objective of this work is to achieve a device with a bandwidth at least ten times greater than the bandwidth of the available commercial piezoelectric sensors. In order to overcome the above-mentioned limitations of these sensors, we report here the design of a new piezoresistive pressure sensor based on a silicon membrane and silicon gauges. The piezoresitive detection has been chosen because it provides a better signal-to-noise ratio than their capacitive counterpart .
J.DUPLOUY, C.MORLAAS, H.AUBERT, P.POTIER, P.POULIGUEN, C.DJOMA
MINC, ENAC, DGA, Bruz
Manifestation avec acte : International Symposium on Antennas and Propagation ( IEEE-APS ) 2017 du 09 juillet au 14 juillet 2017, San Diego (USA), Juillet 2017, 2p. , N° 17341
In this communication, a wideband vector sensor for embedded applications is proposed. This original sensor is composed of two orthogonal and colocated semi-circular arrays of Vivaldi antennas mounted over a ground plane. Stable radiation patterns of two wideband magnetic dipoles and one wideband electric dipole are obtained from full-wave electromagnetic simulations over a 1.69:1 impedance bandwidth with an original control of the excitation.
A.TAKACS, S.CHARLOT, P.F.CALMON, D.DRAGOMIRESCU
Manifestation avec acte : International Symposium on Antennas and Propagation ( IEEE-APS ) 2017 du 09 juillet au 14 juillet 2017, San Diego (USA), Juillet 2017, 2p. , N° 17118
D.HENRY, J.HESTER, H.AUBERT, P.PONS, E.TENTZERIS
MINC, Georgia Institute
Manifestation avec acte : IEEE International Microwave Symposium ( IMS ) 2017 du 04 juin au 09 juin 2017, Honolulu (USA), Juin 2017, 4p. , N° 17258
This paper reports for the first time a long-range interrogation (> 50 meters) of wireless and batteryless humidity sensors combining a Van-Atta retrodirective array and a 3D beam scanning using a 24GHz Frequency-Modulated Continuous-Wave radar. Van-Atta cross-polarization properties, as well as the use of dedicated statistical estimators and Synthetic Aperture Radar technique allow the long-range measurement of the relative humidity at a distance of 58 meters. A measurement sensitivity of 0.2dB to 0.4dB per %RH was measured as a linear variation of the proposed estimator with a standard error of ±0.005dB.
D.HENRY, H.AUBERT, T.VERONESE, E.SERRANO
MINC, Ovalie Innovations, IFV
Revue Scientifique : IEEE Instrumentation & Measurement Magazine, Vol.20, N°3, pp.20-24, Juin 2017 , N° 17357
For better benefits and yields, a good estimation of the quantity of grapes in a vineyard is necessary. In this paper, a three-dimensional (3D) imagery technique using conventional 24 GHz frequency-modulated continuous-wave (FMCW) radar is applied for detecting and remotely estimating the intra-parcel quantity of grapes. An estimation is possible even in the presence of natural or artificial clutters such as leaves, wood, or irrigation hoses. The microwave sensing is performed from the radar beam scanning of a vineyard, and an estimator is defined to derive the quantity of grapes in grapevines from the radar echoes distribution in the interrogated 3D scene. An algorithm based on contour detection is applied to the 3D radar image and a new parameter, called the spread factor, is defined for classifying the echo levels of grapes. The quantity of grapes is finally deduced from an appropriate estimator. This remote sensing approach brings a new and flexible solution for precision viticulture by estimating the grape quantity even for grapes hidden by leaves.