Multi-Layer Tissue Structure Transcutaneous Electric Field Coupled Wireless Power Transfer System for Human Implantable Devices
Cai Chunwei1,2, Chen Tian3, Wu Shuai1,2, Jiao Yujie1, Liu Xichen1
1. School of New Energy Harbin Institute of Technology (Weihai) Weihai 264209 China; 2. Qingdao Research Institute Harbin Institute of Technology (Weihai) Qingdao 266109 China; 3. Wuhan Power Supply Company of State Grid Hubei Electric Power Co. Ltd Wuhan 430010 China
Abstract：Electric-field-coupled wireless power transfer (WPT) offers the advantages of low electro- magnetic interference, low eddy current loss, and lightweight coupler structures. However, current research on electric-field-coupled WPT for human implantable devices typically assumes a single-layer human-tissue model as the energy-transmission medium. In practical applications, the flexible film electrode, used as a receiver, is usually implanted between the skin and fat. Thus, the structure of multi-layer tissue has significant research potential for electric-field-coupled WPT. In this paper, a multi-layer tissue-structure transcutaneous electric- field-coupled WPT system is investigated from three aspects: circuit modeling, coupling device design, and safety assessment. To address the limitations of traditional circuit models in complex human environments, a precise human-tissue circuit model is developed. The dielectric properties of human tissues are studied using the fourth- order Cole-Cole model, and the tissue loss angle, which quantifies energy dissipation across frequencies, serves as the criterion for frequency selection. A multi-tissue-layer circuit model of the human body that incorporates current and voltage distributions is developed. Accordingly, the power distribution in the power transfer link and the system efficiency are analyzed to identify the parameters that affect the transcutaneous link's energy transfer performance. To address the specific requirements of the multi-layer tissue circuit model, the coupler is designed, and its transmission characteristics are investigated. Firstly, the insulation layer thickness is optimized using power transfer efficiency as the criterion. The insulation layer thickness is selected, and the resonant frequency is determined to be 3 MHz. Then, the S-S compensation circuit is designed to clarify the influence on the power transfer link. Ultimately, the power-transfer capacity of the designed coupler is examined. The results show that the designed coupler is insensitive to transmitter separation and to misalignment in the X and Y directions, making it suitable for subcutaneous implants. To ensure the safety of the transcutaneous power transfer link, a safety assessment is conducted on the designed coupler. Using IEEE C95.1 as the safety criterion, the safety assessment is based on the electric field's specific absorption rate in COMSOL. The energy transfer capabilities at different frequencies are compared. Subsequently, the tissue temperature rise is evaluated using the temperature field simulation. The tissue temperature rise during one hour of charging is under 0.789℃, which meets the IEEE C95.1 thermal safety regulations. An experimental platform using fresh pork is set up. The optimized coupler design is verified through comparative experiments with insulating layers of different thicknesses. The simulation, analytical calculation, and experimental results agree well with the proposed circuit model. The power delivered to the load is 107 mW, and the link efficiency is 45.48%, thereby verifying the excellent energy transmission capability of the designed coupler.
蔡春伟, 陈天, 武帅, 焦宇杰, 刘希琛. 多组织层结构经皮电场耦合的人体植入式设备无线电能传输系统[J]. 电工技术学报, 2026, 41(10): 3260-3272.
Cai Chunwei, Chen Tian, Wu Shuai, Jiao Yujie, Liu Xichen. Multi-Layer Tissue Structure Transcutaneous Electric Field Coupled Wireless Power Transfer System for Human Implantable Devices. Transactions of China Electrotechnical Society, 2026, 41(10): 3260-3272.
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