Using dual-antenna nanosecond pulse near-field sensing technology for non-contact and continuous blood pressure measurement

Long-term and continuous non-invasive blood pressure monitoring has shown that it is the most important to clinical diagnosis of cardiovascular diseases and personal home health care. Currently, there are many preferable non-invasive methods, including optical sensor, pressure-sensitive transducers, and applanation tonometry, to get insight of blood pressure and flow signal detection. However, the operation of traditional monitors is cuff accessories needed, and also the sensing probes needed to exert pressure to the user directly. The measurement procedure is limited by long-term, continuous measurement and also easy to cause discomfort. To improve these issues, the non-pressurized and non-invasive measuring method will become an important innovation improvement. In this paper, the novel nanosecond pulse near-field sensing (NPNS) based screening technology with dual-antenna, which includes radio frequency (RF) pulse transmission and two combined flat antenna connected to transceiver of miniature radar, is proposed to derive relative blood pressure parameters from measured blood flow activity (Pulse Wave Velocity, PWV). A dedicated analysis software is also provided to calculate cardiovascular parameters, including PWV, average systolic time, diastolic and systolic pressure, for clinical and homecare applications. To evaluate the performance, the proposed method was applied on blood pressure measurement at the body site of limbs (brachial and leg). As a result, it shows error of DBP and SBP is 5.18 ± 1.61 and 4.09 ± 1.69 mmHg in average compared with the measurement result from commercial product, and performs the capability of continuous long-term monitoring in real-time.