A novel vital-sign sensor using a self-injection-locked oscillator reliably detected heartbeat signals at a distance of 4 m with an operating frequency of 3.6 GHz and output power of 0 dBm.
A novel self-injection-locked oscillator sensor enables noncontact cardiopulmonary monitoring at distances up to 4 meters.
A novel vital-sign sensor with a self-injection-locked oscillator and a frequency demodulator to reduce system complexity and improve sensitivity is proposed. The theory provides a delta-sigma model to account for the excellent signal-to-noise spectral density ratio in a parametric study of the sensitivity performance. Then, the experiments verify the sensing principle and the predicted performance. Accordingly, a prototype sensor with high sensitivity is realized for noncontact cardiopulmonary monitoring, achieving a long sensing distance without the need for a low-noise amplifier. The sensing distance can grow four times longer by doubling the operating frequency. Furthermore, the sensor using a swept frequency can eliminate the null detection points and the external radio interference. As an experimental result, the sensor, which is placed 4 m away from the subject, can reliably detect the heartbeat signal an the operating frequency of 3.6 GHz and an output power level of 0 dBm.
Wang et al. (Thu,) conducted a other in Noncontact cardiopulmonary monitoring. Vital-sign sensor with a self-injection-locked oscillator and a frequency demodulator was evaluated on Heartbeat signal detection at a distance. A novel vital-sign sensor using a self-injection-locked oscillator reliably detected heartbeat signals at a distance of 4 m with an operating frequency of 3.6 GHz and output power of 0 dBm.