Far Field Wireless Power Transfer to Biomedical Implants using Metamaterial

In this article, the far field wireless power transfer (WPT) for charging biomedical implants using metamaterial is proposed. The 3D-model of the voxel human body is taken in the CST Microwave Studio environment and the study is carried out. To power the biomedical implants in the far field region, the voxel is placed at the distance of 723 mm (≥ 2D²/λ = 721 mm, where D is the maximum dimension of the antenna and λ = 122.45 mm) from the aperture of the horn-antenna. The input power to the antenna is maintained to 0.5 W according to the federal communication commission (FCC) rules. Without the metamaterial (MM), the power density in W/m² at the skin, skeleton muscles, bones are 2.97, 2.95 and 2.9 W/m² respectively. With the MM, the respective values are 3.46, 3.44 and 3.38 W/m². The WPT with MM in biomedical implants can be implemented taking into consideration the average and maximum permissible SAR value for the human exposure. Improvement of 17% in the received power with MM as compared to without MM is seen, thus giving more power to the implants. The MM array also helps in beam shaping and try to confine the area of microwave, thus exposing fewer tissues to the waves. Improvement in the rectenna can help in harvesting more power from the source