Wearable electrically small loop antennas (ESLAs) are introduced to monitor joint flexion and rotation while overcoming limitations in the state-of-the-art. The reported approach is not restricted to laboratory environments, does not suffer from integration drift and line-of-sight, and does not impede natural movement. Our previous work introduced wrap-around coils that addressed the challenges above but were limited to monitoring joint flexion. In contrast, a new class of ESLAs is herewith proposed, placed longitudinally across the joint, and operated at 34 MHz to monitor both flexion and rotation. An added advantage versus our previous design is a remarkable improvement in flexion angle resolution: the transmission coefficient dynamic range for 0° – 100° flexion improves by 18.8 dB in this article. Two ESLAs are shown to accurately detect flexion/rotation for angular resolutions up to 10°. However, if higher resolution is desired, ambiguities arise. To tackle this, a three-ESLA system with integrated post-processing is proposed that achieves resolution as high as 2°. Simulations and in vitro experiments are in excellent agreement. Guidelines for system design suited to diverse applications are discussed, and conformance with safety standards is ensured. In future, ESLAs can be seamlessly integrated in garments, enabling transformative benefits to healthcare, sports, and beyond.

中文翻译：

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用于监测关节屈曲和旋转的可穿戴电子小环形天线

可穿戴电子小环形天线 (ESLA) 被引入以监测关节屈曲和旋转，同时克服最先进技术的局限性。报告的方法不限于实验室环境，不受积分漂移和视线的影响，也不会阻碍自然运动。我们之前的工作介绍了解决上述挑战的环绕线圈，但仅限于监测关节屈曲。相比之下，本文提出了一类新的 ESLA，纵向放置在关节上，并在 34 MHz 下运行以监测屈曲和旋转。与我们之前的设计相比，另一个优势是屈曲角度分辨率的显着提高：本文中 0° – 100° 屈曲的传输系数动态范围提高了 18.8 dB。显示两个 ESLA 可以准确检测屈曲/旋转，角度分辨率高达 10°。然而，如果需要更高的分辨率，就会出现歧义。为了解决这个问题，提出了一种具有集成后处理功能的三 ESLA 系统，该系统可实现高达 2° 的分辨率。模拟和体外实验非常吻合。讨论了适合各种应用的系统设计指南，并确保符合安全标准。未来，ESLA 可以无缝集成到服装中，为医疗保健、运动等领域带来变革性的好处。模拟和体外实验非常吻合。讨论了适合各种应用的系统设计指南，并确保符合安全标准。未来，ESLA 可以无缝集成到服装中，为医疗保健、运动等领域带来变革性的好处。模拟和体外实验非常吻合。讨论了适合各种应用的系统设计指南，并确保符合安全标准。未来，ESLA 可以无缝集成到服装中，为医疗保健、运动等领域带来变革性的好处。