Noncontact physiological dynamics detection using low-power digital-IF doppler radar

Heng Zhao, Hong Hong, Li Sun, Yusheng Li, Changzhi Li, Xiaohua Zhu

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


The instantaneous vital sign rates, which are related to physiological dynamics, are important indicators of human health condition. This paper presents a noncontact way to measure the human instantaneous vital signs using digitalintermediate frequency (IF) Doppler radar. The synchrosqueezing transform-based algorithm has been proposed to get a concentrated time-frequency (TF) distribution, so that the highresolution instantaneous heartbeat and respiratory rates and the time-domain signals can be acquired. Moreover, the developed radar with customized radio frequency module employs the direct IF sampling technique to achieve high sensitivity to capture the tiny vital sign variations. Experiments with different human subjects and physiological conditions have been carried out. Compared with the landmark-based method and traditional TF algorithms, the results show that instantaneous vital signs can be acquired more accurately within 3 m at a 13 dBm transmit power by the proposed method. Therefore, the radar can be used for evaluating the physiological dynamics and assessing health condition.

Original languageEnglish
Article number7872421
Pages (from-to)1780-1788
Number of pages9
JournalIEEE Transactions on Instrumentation and Measurement
Issue number7
StatePublished - Jul 2017


  • Doppler radar
  • instantaneous vital sign
  • noncontact vital sign detection
  • synchrosqueezing transform (SST)
  • time-frequency (TF) analysis


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