Multi-coil approach to reduce electromagnetic energy absorption for wirelessly powered implants

Healthcare Technology Letters

article

Anil Kumar RamRakhyani¹  Gianluca Lazzi¹ 

[1] Department of Electrical and Computer Engineering, University of Utah

关键词: prosthetic power supplies;    inductive power transmission;    biological tissues;    coils;    absorption;    power transfer efhciency;    implant electronics;    two-coil WPT system;    SAR;    three-coil WPT system;    specific absorption rate;    multicoil-based WPT technique;    induced electric field;    tissue;    magnetic coil;    biomedical implant coils;    wireless power transfer;    near-held inductive coupling;    multicoil approach;    wirelessly powered implant;    electromagnetic energy absorption reduction;   

DOI  :  10.1049/htl.2013.0035

学科分类：肠胃与肝脏病学

来源: Wiley

【 摘 要 】

Near-field inductive coupling is a commonly used technique for wireless power transfer (WPT) in biomedical implants. Owing to the close proximity of the implant coil(s) with the tissue (∼1 mm) and high current (∼100–300 mA) in the magnetic coil(s), a significant induced electric field can be generated for the operating frequency (1–20 MHz). In this Letter, a multi-coil-based WPT technique is proposed to selectively control the currents in the external and implant coils to reduce the specific absorption rate (SAR). A three-coil WPT system, that can achieve 26% reduction in peak 1-g SAR and 15% reduction in peak 10-g SAR, as compared to a two-coil WPT system with the same dimensions, is implemented and used to demonstrate the effectiveness of the proposed approach. To achieve the seamless design for the external and implant electronics, the multi-coil system achieves the same voltage gain and bandwidth as the two-coil design with 46% improvement in the power transfer efficiency.

【 授权许可】

CC BY|CC BY-ND|CC BY-NC|CC BY-NC-ND