Design and characterization of MEMS-based flow-rate and flow-direction microsensor

Chia Y. Lee, Chih-yung Wen, Hui Hsiung Hou, Ruey J. Yang, Chien Hsiung Tsai, Lung Ming Fu

Research output: Journal article publicationJournal articleAcademic researchpeer-review

29 Citations (Scopus)


This study designs and characterizes a novel MEMS-based flow-rate micro-sensor consisting of a platinum resistor deposited on a silicon nitride-coated silicon cantilever beam. Due to the difference between the thermal conductivities of the silicon nitride film and the silicon beam, the tip of the cantilever structure bends slightly in the upward direction. As air travels across the upper surface of the sensor, it interferes with the curved tip and displaces the beam in either the upward or the downward direction. The resulting change in the resistor signal is then used to calculate the velocity of the air. A flow-direction micro-sensor is constructed by arranging eight cantilever structures on an octagonal platform. Each cantilever is separated from its neighbors by a tapered baffle plate connected to a central octagonal pillar designed to attenuate the aerodynamic force acting on the cantilever beams. By measuring the resistor signals of each of the cantilever beams, the micro-sensor is capable of measuring both the flow rate and the flow direction of the air passing over the sensor. A numerical investigation is performed to examine the effects of the pillar height and pillar-to-tip gap on the airflow distribution, the pressure distribution, the bending moment acting on each beam, and the sensor sensitivity. The results show that the optimum sensor performance is obtained using a pillar height of 0.75 mm and a pillar-to-tip gap of 5 mm. Moreover, the sensitivity of the octagonal sensing platform is found to be approximately 90% that of a single cantilever beam.
Original languageEnglish
Pages (from-to)363-371
Number of pages9
JournalMicrofluidics and Nanofluidics
Issue number3
Publication statusPublished - 9 Jan 2009
Externally publishedYes


  • Flow-direction
  • Flow-rate
  • MEMS
  • Micro-sensor

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Materials Chemistry
  • Condensed Matter Physics


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