Metamaterial integrated highly efficient wireless power transfer system for implantable medical devices

Abstract

In this article, a novel and highly efficient metamaterial (MTM) integrated approach is presented for the development of a wireless power transfer system (WPT) specifically tailored for implantable medical devices. The system is designed by using a biocompatible implantable ring slot antenna constructed on a flexible dielectric, functioning as a receiving (Rx) antenna. Additionally, a conventional patch antenna is modelled for the use in free space, serving as an external transmitting (Tx) element. By exploiting the unique characteristics of MTMs, the power transfer efficiency (PTE) of the introduced system is effectively improved. To ensure the system’s performance stability in real-time application scenario, the effects of misalignment (lateral and angular) and the flexibility of the implantable antenna are meticulously performed. The prototypes of the Tx, Rx, and MTM structures are fabricated, and comprehensive measurements are performed in human-equivalent tissue models, such as skin-mimicking gel and minced pork. Both the simulated and measured results established the proposed methodology, showcasing marked improvements in PTE due to the use of MTMs. The efficiency of the pioneering MTM-integrated WPT system increases from 0.19% to 3.07% in skin-mimicking gel and from 0.24% to 3.26% in minced pork, respectively. This study highlights the potential of MTM-integrated WPT systems in advancing the field of implantable medical devices and expanding their practical applicability.