High detection performance of NDIR CO2 sensor using stair-tapered reflector

Ji Hoon Han, Sang Wook Han, Se Min Kim, James Jungho Pak, Sung Moon

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


In this paper, we propose tapered reflectors having stair-like structures that focus scattered infrared (IR) rays to enhance the detection perfoance of a non-dispersive IR (NDIR) CO2 sensor. We demonstrate that the sensitivity of the output voltage is increased by 2 and 1.27 times in simulations and experiments, respectively, compared with the case when conventionally tapered reflectors are used. Through applying a stair-like structure inside the tapered optical cavity, scattered IR rays are condensed, and more accurate CO2 concentration measurements are possible. In addition, we show that the output voltage changes only slightly with temperature and humidity variations compared with the conventionally tapered optical cavity. Because the proposed structure can be applied to any type of optical cavity without major modifications, we expect that it can resolve the perfoance limitations of low-end NDIR gas sensors.

Original languageEnglish
Article number6514920
Pages (from-to)3090-3097
Number of pages8
JournalIEEE Sensors Journal
Issue number8
Publication statusPublished - 2013


  • Angle of incidence
  • non-dispersive infrared (NDIR)
  • scattered ray
  • stair-tapered reflector

ASJC Scopus subject areas

  • Instrumentation
  • Electrical and Electronic Engineering


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