A Novel Vital-Sign Sensor Based on a Self-Injection-Locked Oscillator

作者：Wang, Fu-Kang^*; Li, Chien-Jung; Hsiao, Chieh-Hsun; Horng, Tzyy-Sheng; Lin, Jenshan; Peng, Kang-Chun; Jau, Je-Kuan; Li, Jian-Yu; Chen, Cheng-Chung

来源：IEEE Transactions on Microwave Theory and Techniques, 2010, 58(12): 4112-4120.

DOI：10.1109/TMTT.2010.2087349

• Delta-sigma model
• frequency demodulator
• self-injection-locked oscillator
• vital-sign sensor

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.

• 出版日期2010-12
• 单位中山大学