A miniaturized dual band implantable antenna and WPT system with enhanced coupling

This article presents a compact dual-band skin implantable antenna for biomedical applications in the ISM 2.4 GHz band and WMTS 1.4 GHz band. An effective permittivity calculation technique was used to ensure antenna operation at the desired bands. It exhibits a compact volume of 0.0984 λ 0 × 0.082 λ 0 × 0.00468 λ 0 . This study presents a complete system comprised of a Wireless Power Transmitter antenna (WPT X ), a rectifier, and an implantable antenna. The WPT antenna has been designed at 1.4 GHz frequency with dimensions of 6 cm × 6 cm × 0.32 cm. The WPT antenna has been used for wireless charging of a static implant and with the parasitic element (consisting of a triple ring) the coupling between WPT and the implantable antenna is improved by 11.57 dB. The rectifier has been optimized for 1.4 GHz and used a voltage tripler topology, with a high RF-to-direct current rectification efficiency of 58.6 %. The fabricated WPT and implantable antennas are tested and measured to validate their characteristics. For analysis of Specific Absorption Rate (SAR), the bare antenna was studied in the human scalp and skin phantoms. WPT SAR compliance has been studied and goes well with international guidelines for SAR.