Many health diagnostic systems demand noninvasive sensing of respiratory rate, respiratory volume, and heart rate with high user comfort. Previous methods often require multiple sensors, including skin-touch electrodes, tension belts, or nearby off-the-body readers, and hence are uncomfortable or inconvenient. This paper presents an over-clothing wearable radio-frequency sensor study, conducted on 20 healthy participants (14 females) performing voluntary breathing exercises in various postures. Two prototype sensors were placed on the participants, one close to the heart and the other below the xiphoid process to couple to the motion from heart, lungs and diaphragm, by the near-field coherent sensing principle. We can achieve a satisfactory correlation of our sensor with the reference devices for the three vital signs: heart rate (r = 0.95), respiratory rate (r = 0.93) and respiratory volume (r = 0.84). We also detected voluntary breath-hold periods with an accuracy of 96%. Further, the participants performed a breathing exercise by contracting abdomen inwards while holding breath, leading to paradoxical outward thorax motion under the isovolumetric condition, which was detected with an accuracy of 83%.

许多健康诊断系统需要以高用户舒适度对呼吸频率、呼吸量和心率进行无创传感。以前的方法通常需要多个传感器，包括皮肤接触电极、张力带或附近的离体读取器，因此不舒服或不方便。本文介绍了一项覆盖衣服的可穿戴射频传感器研究，该研究对 20 名健康参与者（14 名女性）进行，以各种姿势进行自主呼吸练习。两个原型传感器被放置在参与者身上，一个靠近心脏，另一个位于剑突下方，通过近场相干传感原理耦合来自心脏、肺和膈肌的运动。我们的传感器与参考设备可以在三个生命体征方面实现令人满意的相关性：心率 ( r = 0.95)、呼吸频率 ( r = 0.93) 和呼吸量 ( r = 0.84)。我们还检测了自主屏气时间，准确率为 96%。此外，参与者通过屏住呼吸的同时向内收缩腹部进行呼吸练习，导致等容条件下胸部反常向外运动，检测准确率为83%。