Highly integrated two-port rectenna system for wirelessly-powering multi-site autonomous vascular implantable networks

Abstract

This study presents a network of highly-integrated dual-port implantable rectennas for multi-site wireless power transfer(WPT) to miniature implantable vascular devices. The WPT system consists of a flexible transmitter dipole antenna and two-port dual-band implantable antennas that enable simultaneous wireless information and power transfer(SWIPT). The rectenna occupies a compact size of 7.0 × 7.0 × 0.635 mm3 and operates at 915 MHz and 2.45 GHz with over 25 dB isolation between the two ports. A single-inductor-matched voltage doubler is integrated into the ground layer of the implantable antenna without adding volume or degrading performance, achieving a power conversion efficiency of 73.9% at 5 dBm across a 5.89 kΩ load. The rectenna was tested ex vivo at implantation depths varying from 1 cm to 5 cm in a porcine tissue, resulting in 2.24 mW of DC power transferred at a low input power level of 26 dBm, at an implantation depth of 3 cm. Next, a multi-site implantable WPT system with three rectenna channels was demonstrated, achieving output voltages of 1.68 V at an input power of 25 dBm and implantation depth of 4.5 cm. Wireless power transfer experiments using micro-LEDs as visual indicators, and quantitative rectenna measurements demonstrate the ability of the system to support multi-site autonomous vascular implants.