Wearable sensors based on a high sensitive complementary split-ring resonator for accurate cardiorespiratory sign measurements

This paper presents a novel wearable complementary split-ring resonator (CSRR) sensor for smart clothing to measure cardiorespiratory signs. The cardiorespiratory vital signs can be measured in the frequency and amplitude deviations of CSRR caused by the slight displacement from the chest. The heart signals can be extracted from the respiratory signals simultaneously by using a high sensitive CSRR sensor. Based on the proposed approach, the heartbeat can be significantly compared with traditional vital sign detection. Experiment results reveal that the CSRR can determine accurately the physiological signals. From the tracking resonant frequency and amplitude S21, the heartbeat rate and respiratory rate has errors of 0.01% and 0.04%, respectively. At a fixed frequency of 1.1 GHz, cardiorespiratory signals are measured to achieve low error of 0.01%. The proposed method is promising for healthcare applications.