Experimental 2.4 GHz CMOS RF front-ends for non-contact vital-sign sensing

• Published in: Electronics letters Vol. 51; no. 23; pp. 1846 - 1848
• Main Authors: Wang, S, Chang, R.-H
• Format: Journal Article
• Language: English
• Published: The Institution of Engineering and Technology 05.11.2015
• Subjects: Amplification; bioelectric phenomena; biomedical electronics; Biomedical technology; Circulation; circulator; CMOS; CMOS integrated circuits; CMOS RF front‐ends; demodulators; Detection; differential oscillator; electric sensing devices; frequency 2.4 GHz; injection‐locked function; low‐power electronics; lumped power divider; Mixers; noncontact vital‐sign sensing; Oscillators; phase demodulator; power 32 mW; Power consumption; power dividers; Respiration; system complexity; UHF integrated circuits; oscillators; phase demodulator; power 32 mW; CMOS RF front-ends; noncontact vital-sign sensing; circulator; power dividers; injection-locked function; demodulators; frequency 2.4 GHz; system complexity; lumped power divider; biomedical electronics; bioelectric phenomena; differential oscillator; CMOS integrated circuits; UHF integrated circuits; electric sensing devices; low-power electronics
• ISSN: 0013-5194; 1350-911X; 1350-911X
• DOI: 10.1049/el.2015.3033

A 2.4 GHz CMOS front-ends for non-contact vital-sign sensing including respiration and heartbeat is presented. The sensor using one circulator and one differential oscillator not only achieves the injection-locked function but also reduces the system complexity. Moreover, the injection-locked signals are then down-converted by a phase demodulator constituted by a lumped power divider and a mixer. Finally, the signals are bandpass filtered and amplified for subsequently performing the vital signals. Under total power consumption of 32 mW, the respiration and heartbeat information can be recognised correctly up to 1.2 m away from the subject.