School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
Dr. Ambedkar National Institute of Technology, Jalandhar, 144011, India.
Sci Rep. 2023 Jun 19;13(1):9935. doi: 10.1038/s41598-023-36717-w.
Assistive devices are becoming increasingly popular for physically disabled persons suffering tetraplegia and spinal cord injuries. Intraoral tongue drive system (iTDS) is one of the most feasible and non-invasive assistive technology (AT), which utilises the transferring and inferring of user intentions through different tongue gestures. Wireless transferring is of prime importance and requires a suitable design of the intra-oral antenna. In this paper, a compact circularly polarized differential intra-oral antenna is designed, and its performance is analysed within heterogeneous multilayer mouth and head models. It works at 2.4 GHz in the Industrial, Scientific, and Medical (ISM) band. The footprint of the differential antenna prototype is 0.271 λ [Formula: see text] 0.271 λ [Formula: see text] 0.015 λ. It is achieved using two pairs of spiral segments loaded in diagonal form near the edges of the central rotated square slot and a high dielectric constant substrate. Its spiral-slotted geometry further provides the desired swirling and miniaturization at the desired frequency band for both mouth scenarios. Additionally, corner triangular slits on the radiating patch assist in tuning the axial ratio (< 3 dB) in the desired ISM band. To validate the performance of the proposed in-mouth antenna, the measurement was carried out using the minced pork and the saline solution for closed and opened mouth cases, respectively. The measured - 10 dB impedance bandwidth and peak gain values in the minced pork are from 2.28 to 2.53 GHz (10.39%) and - 18.17 dBi, respectively, and in the saline solution, are from 2.3 to 2.54 GHz (9.92%) and - 15.47 dBi, respectively. Further, the specific absorption rate (SAR) is estimated, and the data communication link is computed with and without a balun loss. This confirms that the proposed differential intraoral antenna can establish direct interfacing at the RF front end of the intraoral tongue drive system.
辅助设备对于患有四肢瘫痪和脊髓损伤的身体残疾人士越来越受欢迎。口腔内舌驱动系统 (iTDS) 是最可行和非侵入性的辅助技术 (AT) 之一，它利用通过不同的舌动作来传输和推断用户意图。无线传输至关重要，需要设计合适的口腔内天线。本文设计了一种紧凑的圆形极化差分口腔内天线，并在异质多层口腔和头部模型中分析了其性能。它在工业、科学和医疗 (ISM) 频段的 2.4GHz 下工作。差分天线原型的足迹为 0.271 λ [公式：见文本] 0.271 λ [公式：见文本] 0.015 λ。它是通过两对螺旋段在中央旋转正方形槽的边缘附近以对角线形式加载以及使用高介电常数衬底来实现的。其螺旋开槽几何形状进一步在所需的口腔情况下为所需的频带提供了期望的旋转和小型化。此外，辐射贴片上的角三角形缝隙有助于在所需的 ISM 频段中调谐轴比（<3dB）。为了验证口腔内天线的性能，使用肉末和盐水溶液分别进行了封闭和开口口腔的测量。在肉末中的测量-10dB 阻抗带宽和峰值增益值分别为 2.28 至 2.53GHz（10.39%）和-18.17dBi，在盐水中，分别为 2.3 至 2.54GHz（9.92%）和-15.47dBi。此外，还估计了比吸收率 (SAR)，并计算了带有和不带有平衡器损耗的数据通信链路。这证实了所提出的差分口腔内天线可以在口腔内舌驱动系统的射频前端建立直接接口。
