Efficient Power Transfer to Implanted Antennas

Wireless power transfer between an external electromagnetic (EM) source and implanted dipoles into human body can be greatly assisted by employing a matching part atop of the skin. Two different approaches are proposed: one incorporating lossless layers that minimize the reflections and another dealing with active metasurfaces that boost the transmissivity. Obviously, the performance is higher in the latter scenario since gain media are involved; however, even with passive layers, significant enhancement in the coupling between the two radiators is achieved. These coupling scores exhibit substantial robustness under the condition of misaligned dipoles, a feature that renders them suitable to operate under experimental imperfections. The proposed concept has been experimentally demonstrated at bluetooth frequencies leading to strong enhancement of power transmission, even when the radiation patterns of the two antennas are heavily misaligned. Accordingly, the reported designs can be utilized in biomedical setups that call for fast and reliable wireless communication: from healthcare monitoring and biosensing to real-time drug delivery and bioimaging.