MEMS piezoresistive flow sensors for sleep apnea therapy

Behrokh Abbasnejad, William Thorby, Amir Razmjou, Dayong Jin, Mohsen Asadnia, Majid Ebrahimi Warkiani*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)


A MEMS liquid crystal polymer (LCP), used in the membrane-based pressure sensor, has been found highly useful as a flow sensor. Here we conducted a set of elaborate experiments using an air flow generator to investigate the potential of our LCP flow sensor for sleep apnea therapy. Critical properties of the LCP flow sensor, including flow range, resolution (sensitivity), accuracy, and response time, have been systematically characterized. As a result, LCP flow sensor achieves a limit of detection of 8 LPM to measure flow rate, better than the commercial flow sensor (>10 LPM). Our LCP flow sensor shows a favourable response in a large flow range (8–160 LPM) with a sensitivity of detecting a linear voltage response of 0.004 V per 1 LPM flow rate. With minimum detectable flow, high sensitivity and resolution, we further demonstrated our LCP flow sensor for detecting human respiration. Moreover, using a two- dimensional simulation in COMSOL Multiphysics, we demonstrated the deformation of LCP membrane in response to different flow velocities which leads to resistance change in sensor's strain gauge.

Original languageEnglish
Pages (from-to)577-585
Number of pages9
JournalSensors and Actuators, A: Physical
Publication statusPublished - 15 Aug 2018


  • Breath analyzer
  • MEMS flow sensor
  • Liquid crystal polymer


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