Review of Near-Field Wireless Power and Communication for Biomedical Applications

Near-field magnetic wireless systems have distinct advantages over their conventional far-field counterparts in water-rich environments, such as underwater, underground, and in biological tissues, due to lower power absorption. This paper presents a comprehensive review of near-field magnetic wireless power transfer (WPT) and communication technologies in a variety of applications from general free-space systems, to implantable biomedical devices we find of particular interest. To implement a fully wirelessly-powered implantable system, both high-efficiency power transfer and high-rate data communication are essential. This paper first presents the history and the fundamentals of near-field WPT and communication in free-space systems, followed by technical details for their specific use in implantable biomedical devices. Finally, this paper reviews recent advances in simultaneous wireless information and power transfer and highlights their applications in implantable biomedical systems. The knowledge reviewed in the paper could provide intuition in the design of various wireless and mobile systems such as wireless body area networks, small-cell 5G cellular, as well as in-body biomedical applications, especially for efficient power and data management and higher security.