This paper studies the performance of a resonant capacitive wireless power transfer (C-WPT) link for biomedical implants in the presence of non-idealities. The study emphasizes on finding an accurate electrical model of a practical C-WPT link, which can be used to investigate the performance of the link under different practical/non-ideal scenarios. A sound knowledge about these non-idealities is crucial for device optimization. For the first time, a circuit model has been presented and analyzed, which is applicable to a practical C-WPT link undergoing plate mismatch, flexion, tissue contraction, and stretching. Our model considers the finite conductivity of the body tissue and fringe fields formed by capacitor plates. Analytical and HFSS ^TM simulation results have been presented for different non-idealities, and are in good agreement. Additionally, we show a procedure to interpolate non-ideal case results. The study shows that plate misalignment (causing reduction in parallel plate overlap area) and skin tissue contraction (while muscle grows) are the most detrimental individual factors to the link performance. We recorded ∼32% and ∼14% power transfer efficiency decrease due to these two worst-case scenarios, respectively for a C-WPT link comprising of two pairs of 400 mm ² parallel plates (12 cm edge-to-edge separation) coated with 63.5 µm thick Kapton layer and aligned around a 3 mm tissue at 20 MHz.

中文翻译：

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关于用于将无线电力传输到生物医学植入物的电容性链路的非理想性

本文研究了在非理想情况下用于生物医学植入物的谐振电容式无线电力传输 (C-WPT) 链路的性能。该研究强调寻找实际 C-WPT 链路的准确电气模型，可用于研究不同实际/非理想场景下的链路性能。充分了解这些非理想情况对于设备优化至关重要。首次提出并分析了一个电路模型，该模型适用于实际的 C-WPT 链路，该链路经历板错配、屈曲、组织收缩和拉伸。我们的模型考虑了身体组织的有限电导率和电容器板形成的边缘场。分析和 HFSS ^TM模拟结果已针对不同的非理想情况进行了介绍，并且非常吻合。此外，我们展示了一个插入非理想情况结果的程序。研究表明，板未对准（导致平行板重叠区域减少）和皮肤组织收缩（同时肌肉增长）是对链路性能最不利的个体因素。由于这两种最坏情况，我们记录了约 32% 和约 14% 的功率传输效率下降，对于 C-WPT 链路，包括两对 400 mm ²平行板（12 cm 边缘到边缘间隔）涂层具有 63.5 µm 厚的 Kapton 层，并在 20 MHz 下围绕 3 mm 组织对齐。