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Biosensors 2016, 6(4), 54;

Wrist Pulse Rate Monitor Using Self-Injection-Locked Radar Technology

Department of Electrical Engineering, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
Author to whom correspondence should be addressed.
Academic Editor: Donald Y.C. Lie
Received: 1 September 2016 / Revised: 7 October 2016 / Accepted: 19 October 2016 / Published: 26 October 2016
(This article belongs to the Special Issue Latest Wearable Biosensors)
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To achieve sensitivity, comfort, and durability in vital sign monitoring, this study explores the use of radar technologies in wearable devices. The study first detected the respiratory rates and heart rates of a subject at a one-meter distance using a self-injection-locked (SIL) radar and a conventional continuous-wave (CW) radar to compare the sensitivity versus power consumption between the two radars. Then, a pulse rate monitor was constructed based on a bistatic SIL radar architecture. This monitor uses an active antenna that is composed of a SIL oscillator (SILO) and a patch antenna. When attached to a band worn on the subject’s wrist, the active antenna can monitor the pulse on the subject’s wrist by modulating the SILO with the associated Doppler signal. Subsequently, the SILO’s output signal is received and demodulated by a remote frequency discriminator to obtain the pulse rate information. View Full-Text
Keywords: wrist pulse rate monitor; continuous-wave (CW) radar; self-injection-locked (SIL) radar; bistatic radar architecture wrist pulse rate monitor; continuous-wave (CW) radar; self-injection-locked (SIL) radar; bistatic radar architecture

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Wang, F.-K.; Tang, M.-C.; Su, S.-C.; Horng, T.-S. Wrist Pulse Rate Monitor Using Self-Injection-Locked Radar Technology. Biosensors 2016, 6, 54.

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