Efficient Wireless Power Transfer System for Implantable Medical Devices Using Circular Polarized Antennas

In this article, we present a novel approach for designing a rotation insensitive, biocompatible, circular polarization-based efficient wireless power transfer (WPT) system for implantable medical devices (IMDs) in the radiative near-field region. Initially, a wideband, biocompatible, flexible circular polarized (CP) slot antenna is designed inside a single-layer skin tissue model to use as a receiving (Rx) element. To create the WPT link, a simple square patch antenna with the truncated corners is constructed to utilize as a transmitting (Tx) element. Furthermore, a polarization conversion-based metamaterial (MTM) structure is built particularly to improve the power transfer efficiency (PTE) of the proposed WPT system. Also, to show the versatility, the performance analysis of the proposed MTM integrated WPT system is conducted inside the human torso and head model. Moreover, a detailed study of the specific absorption rate (SAR) is accomplished regarding the safety of the human body in the light of IEEE regulation. Finally, the prototypes of the proposed WPT system are fabricated and experimentally verified in skin-mimicking gel and minced pork. The experimental result confirms the feasibility of the proposed concept by enhancing the PTE of the presented system by the usage of the MTM slab.