J.J. van Baar

Publications (16)2.11 Total impact

• Source

  Available from: utwente.nl

  Conference Proceeding: Drag Force Actuated Bistable Microswitches for Flow Sensing

  W.J. Kuipers, J.J. van Baar, M. Dijkstra, R.J. Wiegerink, T.S.J. Lammerink, J.H. de Boer, G.J.M. Krijnen
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  ABSTRACT: This paper presents bistable microswitches with Au contacts with the aim to combine them with artificial hairs for flow sensing. The Au contacts are applied on both ends of a silicon nitride beam, suspended by a torsional bar at its center. The beam is provided with electrodes for electrostatic actuation, which were used for characterization and can also be used for adaptive control of the mechanical properties of the flow sensor. The electrodes have been actuated in anti-phase to drive the microswitch similarly to an astable multivibrator. Single-sided switching has been measured up to 10 kHz actuation frequency.
  Micro Electro Mechanical Systems, 2006. MEMS 2006 Istanbul. 19th IEEE International Conference on; 02/2006
• Source

  Available from: utwente.nl

  Article: Artificial sensory hairs based on the flow sensitive receptor hairs of crickets

  M Dijkstra, J J Van Baar, R J Wiegerink, T S J Lammerink, J H De Boer, G J M Krijnen
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  ABSTRACT: This paper presents the modelling, design, fabrication and characterization of flow sensors based on the wind-receptor hairs of crickets. Cricket sensory hairs are highly sensitive to drag-forces exerted on the hair shaft. Artificial sensory hairs have been realized in SU-8 on suspended Si x N y membranes. The movement of the membranes is detected capacitively. Capacitance versus voltage, frequency dependence and directional sensitivity measurements have been successfully carried out on fabricated sensor arrays, showing the viability of the concept.
  J. Micromech. Microeng. 01/2005; 15:132-138.
• Conference Proceeding: Design and Fabrication of Micromachined X-ray Sensors for Space Application

  M.P. Bruijn, H.F.C. Hoevers, E. Krouwer, M.L. Ridder, J.J. van Baar, R. de Boer, R.J. Wiegerink, M. Elwenspoek
  SAFE & ProRISC 2004, Veldhoven, The Netherlands; 11/2004
• Article: Development of an array of transition edge sensors for application in X-ray astronomy

  M.P. Bruijn, N.H.R. Baars, W.M. Bergmann Tiest, A. Germeau, H.F.C. Hoevers, P.A.J. de Korte, W.A. Mels, M.L. Ridder, E. Krouwer, J.J. van Baar, R.J. Wiegerink
  Nuclear Instruments and Methods 01/2004; A(520):443-445.
• Source

  Available from: utwente.nl

  Conference Proceeding: Fabrication of arrays of artificial hairs for complex flow pattern recognition

  J.J. van Baar, M. Dijkstra, R.J. Wiegerink, T.S.J. Lammerink, G.J.M. Krijnen
  [show abstract] [hide abstract]
  ABSTRACT: We present monolithically integrated high-density arrays of artificial hairs for flow pattern measurements based on drag force. A combined bulk/surface micromachining process has been developed to integrate the artificial hairs with capacitive read-out. First fabrication results show the possibility to fabricate out-of-plane hairs without reverting to micro-assembly technologies. This enables realisation of high-density arrays of symmetrical sensors with two-dimensional sensitivity.
  Sensors, 2003. Proceedings of IEEE; 11/2003
• Source

  Available from: utwente.nl

  Conference Proceeding: Pirani pressure sensor with distributed temperature measurement

  B.R. de Jong, W.P. Bula, D. Zalewski, J.J. van Baar, R.J. Wiegerink
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  ABSTRACT: Surface micromachined distributed Pirani pressure gauges, with designed heater-to-heat sink distances (gap-heights) of 0.35 μrn and 1.10 μm, are successfully fabricated, modeled and characterized. Measurements and model response correspond within 5 % of the measured value in a pressure range of 10 to 2*10⁴ Pa. The distributed nature of the sensor facilitates pressure measurement to be independent of the Temperature Coefficient of Resistance of the resistors. This also provides an inherent compensation for heat loss via the membrane supporting the heater, extending the lower pressure range.
  Sensors, 2003. Proceedings of IEEE; 11/2003
• Source

  Available from: utwente.nl

  Conference Proceeding: Micromachined two dimensional resistor arrays for determination of gas parameters

  J.J. van Baar, Verweij WA, M. Dijkstra, R.J. Wiegerink, T.S.J. Lammerink, G.J.M. Krijnen, M. Elwenspoek
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  ABSTRACT: A resistive sensor array is presented for two dimensional temperature distribution measurements in a micromachined flow channel. This allows simultaneous measurement of flow velocity and fluid parameters, like thermal conductivity, diffusion coefficient and viscosity. More general advantages of measuring temperature distributions are the inherent compensation of heat losses to the support and the insensitivity to variations in the temperature coefficient of resistance.
  TRANSDUCERS, Solid-State Sensors, Actuators and Microsystems, 12th International Conference on, 2003; 07/2003
• Source

  Available from: utwente.nl

  Conference Proceeding: Combined Pirani/bending membrane-pressure sensor

  J.J. van Baar, R.J. Wiegerink, T.S.J. Lammerink, E. Berenschot, G.J.M. Krijnen, M. Elwenspoek
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  ABSTRACT: A differential pressure sensor has been realized with thermal readout. The thermal readout allows simultaneous measurement of the membrane deflection due to a pressure difference and measurement of the absolute pressure by operating the structure as a Pirani pressure sensor
  Micro Electro Mechanical Systems, 2002. The Fifteenth IEEE International Conference on; 02/2002
• Source

  Available from: J.W. Berenschot

  Conference Proceeding: Pressure sensor based on distributed temperature sensing

  J.J. van Baar, R.J. Wiegerink, J.W. Berenschot, T.S.J. Lammerink, G.J.M. Krijnen, M. Elwenspoek
  [show abstract] [hide abstract]
  ABSTRACT: A differential pressure sensor has been realized with thermal readout. The thermal readout allows simultaneous measurement of the membrane deflection due to a pressure difference and measurement of the absolute pressure by operating the structure as a Pirani pressure sensor. The measuring of the temperature distribution makes it possible to take the heat transfer to the support in to account and make the measurements independent of the temperature coefficient of resistance of the sensing elements.
  Sensors, 2002. Proceedings of IEEE; 02/2002
• Article: Micromachined structures for thermal measurements of fluid and flow parameters

  J J van Baar, R J Wiegerink, T S J Lammerink, G J M Krijnen, M Elwenspoek
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  ABSTRACT: In this paper thermal sensor-actuator structures are proposed that can be used to measure various fluid parameters such as thermal conductivity, flow velocity, heat capacity, kinematic viscosity and pressure. All structures are designed in such a way that they can be realized in the same fabrication process and therefore they can be easily combined in a single device. All structures are based on the principle of thermal measurements: resistive structures are used for both heating and temperature measurements. For accurate measurements the temperature coefficient of resistance (TCR) must be well known. Therefore, a special structure, which can be used for auto-calibration, was designed to measure the TCR. A first device containing structures for the combined measurement of flow velocity, thermal conductivity and TCR has been fabricated. Measurements show promising results.
  Journal of Micromechanics and Microengineering 07/2001; 11(4):311. · 2.11 Impact Factor
• Source

  Available from: utwente.nl

  Article: Capacitive flow sensors based on receptor hairs of crickets

  M Dijkstra, J J Van Baar, R J Wiegerink, T S J Lammerink, J H De Boer, G J M Krijnen
  [show abstract] [hide abstract]
  ABSTRACT: This paper presents the design and realization of flow sensors based on wind-receptor hairs of crickets. Natural cricket hairs are weakly suspended at their base, resulting in high sensitivity for drag-forces exerted on the hair shaft. The realized structures consist of an SU-8 hair on a membrane with electrodes for capacitive read-out. The structure is suspended by weak silicon-nitride springs, which results in high sensitivity. Initial capacitance versus voltage measurements are in agreement with theory, and show that measuring drag-forces on the artificial hairs is feasible.
• Source

  Available from: utwente.nl

  Article: Micromachined two dimensional resistor arrays for determination of gas parameters

  J J Van Baar, W A Verweij, M Dijkstra, R J Wiegerink, T S J Lammerink, G J M Krijnen, M Elwenspoek
  [show abstract] [hide abstract]
  ABSTRACT: A resistive sensor array is presented for two dimensional temperature distribution measurements in a micromachined flow channel. This allows simultaneous measurement of flow velocity and fluid parameters, like thermal conductivity, diffusion coefficient and viscosity. More general advantages of measuring temperature distributions are the inherent compensation of heat losses to the support and the insensitivity to variations in the temperature coefficient of resistance.
• Source

  Available from: utwente.nl

  Article: Fabrication of arrays of artificial hairs for complex flow pattern recognition

  J J Van Baar, M Dijkstra, R J Wiegerink, T S J Lammerink, G J M Krijnen
  [show abstract] [hide abstract]
  ABSTRACT: We present monolithically integrated high-density arrays of artificial hairs for flow pattern measurements based on drag force. A combined bulk/surface micromachining pro-cess has been developed to integrate the artificial hairs with capacitive read-out. First fabrication results show the possibility to fabricate out-of-plane hairs without reverting to micro-assembly technologies. This enables realisation of high-density arrays of symmetrical sensors with two-dimensional sensitivity. INTRODUCTION The CICADA 1 project [1] aims to contribute to the scien-tific and technological advancements of life-like perception systems within the European Community. The project pro-vides novel concepts for the integration of sensing-perception-action functions, based on exciting scientific work on biological paradigms and state-of-the-art devel-opments in MEMS, composite material science and electro-physiology. In order to create integrated sensing-perception-response systems inspired by nature, many biological paradigms are possible for inspiration, ranging from unicellular organisms to highly complex beings such as higher animals and hu-mans. Among the many choices available, insects offer very good examples of life-like perception because they are sufficiently complex, but amenable to be characterized and quantified, so as to provide a suitable scientific and techni-cal challenge with a realistic chance of success. In the CICADA project we will fabricate artificial hairs inspired by the hairs found on cerci of crickets [2, 3]. It is hypothe-sized that crickets use hairs of several lengths to detect the complex flow patterns produced by their predators. It is the aim of this work to make arrays of artificial hairs to per-form comparable functions.
• Source

  Available from: utwente.nl

  Article: Out of Plane Artificial Hairs for Flow Sensing

  J J Van Baar, M Dijkstra, R J Wiegerink, T S J Lammerink, G J M Krijnen
  [show abstract] [hide abstract]
  ABSTRACT: We present monolithically integrated high-density arrays of artificial hairs for flow pattern meas-urements based on drag force. A combined bulk/surface micromachining process has been developed to inte-grate the artificial hairs with capacitive read-out. First fabrication results show the possibility to fabricate out-of-plane hairs without reverting to micro-assembly technologies. This enables realisation of high-density arrays of symmetrical sensors with two-dimensional sensitivity.
• Source

  Available from: J.W. Berenschot

  Article: 61.6: Pressure sensor based on distributed temperature sensing

  J J Van Baar, R J Wiegerink, J W Berenschot, T S J Lammerink, G J M Krijnen, M Elwenspoek
  [show abstract] [hide abstract]
  ABSTRACT: A differential pressure sensor has been realized with thermal readout. The thermal readout allows simultaneous measurement of the membrane deflection due to a pressure difference and mea-surement of the absolute pressure by operating the structure as a Pirani pressure sensor. The measuring of the temperature distri-bution makes it possible to take the heat transfer to the support in account and make the measurements independent of the tempera-ture coefficient of resistance of the sensing elements.
• Source

  Available from: M.P. Bruijn

  Conference Proceeding: Cryogenic imaging x-ray spectrometer

  R.J. Wiegerink, J.J. van Baar, J.H. de Boer, M.L. Ridder, M.P. Bruijn, A. Germeau, H.F.C. Hoevers
  [show abstract] [hide abstract]
  ABSTRACT: A micro-calorimeter array consisting of superconducting transition-edge sensors is under development for the X-ray imaging spectrometer on board of ESA's XEUS (X-ray Evolving Universe Spectroscopy) mission. An array of 32 × 32 pixels with a pixel size of 250 micron square is envisaged. So far, 5 × 5 pixels arrays were successfully fabricated along two fabrication routes: a bulk micromachining and a surface micromachining route. Both routes result in working arrays with energy resolutions down to 5 eV FWHM for the best pixels.
  Micro Electro Mechanical Systems, 2005. MEMS 2005. 18th IEEE International Conference on;