[1] CHEN Han, LIU Xiangyu, CHENG Jiajun, QIN Jiangfan, et al. Frequency optimization for electrodes in implantable brain-computer interfaces [J]. Journal of Southeast University (English Edition), 2025, 41 (3): 366-374. [doi:10.3969/j.issn.1003-7985.2025.03.012]

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Frequency optimization for electrodes in implantable brain-computer interfaces()

植入式脑机接口电极的频率优化

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Journal of Southeast University (English Edition)[ISSN:1003-7985/CN:32-1325/N]

Volumn:

41

Issue:

2025 3

Page:

366-374

Research Field:

Information and Communication Engineering

Publishing date:

2025-09-11

Info

Title:

Frequency optimization for electrodes in implantable brain-computer interfaces

植入式脑机接口电极的频率优化

Author(s):

CHEN Han^1,2, LIU Xiangyu¹, CHENG Jiajun¹, QIN Jiangfan¹, ZHANG Xueli¹

1.School of Instrument Science and Engineering, Southeast University, Nanjing 210096, China
2.State Key Laboratory of Smart Grid Protection and Control, Nanjing 211106, China

陈翰^1,2, 刘翔宇¹, 程佳君¹, 秦江帆¹, 张雪丽¹

1.东南大学仪器科学与工程学院，南京 210096
2.智能电网保护和运行控制国家重点实验室，南京 211106

Keywords:

brain-computer interfaces;  electromagnetic simulation;  electroencephalography electrodes;  power density;  specific absorption rate

脑机接口; 电磁仿真; 脑电图电极; 功率密度; 比吸收率

PACS:

TN911

DOI:

10.3969/j.issn.1003-7985.2025.03.012

Abstract:

Fully implanted brain-computer interfaces (BCIs) are preferred as they eliminate signal degradation caused by interference and absorption in external tissues, a common issue in non-fully implanted systems. To optimize the design of electroencephalography electrodes in fully implanted BCI systems, this study investigates the penetration and absorption characteristics of microwave signals in human brain tissue at different frequencies. Electromagnetic simulations are used to analyze the power density distribution and specific absorption rate (SAR) of signals at various frequencies. The results indicate that lower-frequency signals offer advantages in terms of power density and attenuation coefficients. However, SAR-normalized analysis, which considers both power density and electromagnetic radiation hazards, shows that higher-frequency signals perform better at superficial to intermediate depths. Specifically, at a depth of 2 mm beneath the cortex, the power density of a 6.5 GHz signal is 247.83% higher than that of a 0.4 GHz signal. At a depth of 5 mm, the power density of a 3.5 GHz signal exceeds that of a 0.4 GHz signal by 224.16%. The findings suggest that 6.5 GHz is optimal for electrodes at a depth of 2 mm, 3.5 GHz for 5 mm, 2.45 GHz for depths of 15-20 mm, and 1.8 GHz for 25 mm.

完全植入式脑机接口（BCI）因避免了非全植入式系统中由外部组织干扰和吸收引起的信号退化而成为优先选择。为优化完全植入式脑机接口系统中的脑电图（EEG）电极设计，本文研究了不同频率下微波信号在人体脑组织中的穿透和吸收特性。通过电磁仿真，分析了不同频率信号的功率密度分布和比吸收率（SAR）。结果表明，较低频率信号在功率密度和衰减系数上具有优势，但综合考虑功率密度与电磁辐射危害的SAR归一化分析表明，较高频率信号在浅至中等深度的穿透表现更好。具体而言，在皮层下2 mm深处，6.5 GHz信号的功率密度比0.4 GHz高247.83%；在5 mm深度，3.5 GHz信号的功率密度比0.4 GHz高224.16%。研究表明，6.5 GHz信号适用于2 mm深度电极，3.5 GHz适合5 mm深度电极，2.45 GHz适合15~20 mm深度电极，1.8 GHz适合25 mm深度电极。

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Memo

Memo:

Received 2024-12-11,Revised 2025-01-16.
Biography: Chen Han (1977─), male, doctor, associate professor, Hanchen@seu.edu.cn.
Foundation item:The Open Project of State Key Laboratory of Smart Grid Protection and Operation Control in 2022 (No. SGNR0000KJJS2302150).
Citation:CHEN Han,LIU Xiangyu,CHENG Jiajun,et al.Frequency optimization for electrodes in implantable brain-computer interfaces[J].Journal of Southeast University (English Edition),2025,41(3):366-374.DOI:10.3969/j.issn.1003-7985.2025.03.012.DOI:10.3969/j.issn.1003-7985.2025.03.012

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