Highly Isolated Wireless Power Transfer and Information Co-Delivery Using a Pacemaker Duplex Antenna

Abstract

This article details developing and verifying a radio frequency (RF) system capable of simultaneously delivering wireless power and information using a leadless pacemaker duplex antenna. The setup comprises a wireless power transfer (WPT) transmitter (Tx), a rectifier, and a duplex antenna. The proposed implantable duplex antenna operates at 915 (when Port-1 is active) and 1300 MHz (when Port-2 is active), enabling simultaneous information delivery at 915 MHz and WPT at 1300 MHz. The implantable antenna operates in the human heart, occupies a small volume of $\pi \times 4.48{^{{2}}} \times 0.13=8.19$ mm3, and maintains a high isolation level of 34.6 dB. To ensure a high level of isolation between the two radiators of the duplex antenna, a series of vias between the radiators and rectangular slots on the ground plane are used. To maintain a compact volume (8.19 mm3), shorting pins and capacitive arc slots along with a high dielectric substrate are incorporated. In addition, an efficient implantable rectifier is simulated, measured, and integrated with Port-2 of the duplex antenna at 1300 MHz. The designed rectifier has an RF-to-direct current (dc) efficiency of 78.3% at 2-dBm input power. Moreover, a slotted-patch antenna is created to serve as the pacemaker’s WPT Tx, maintaining a power transfer efficiency (PTE) of 2.2%. Using two-layered matching materials, the overall PTE of the complete system is found to be 1.72% at 2-dBm input power. Measurements involve embedding the leadless pacemaker device inside minced pork meat, with the measured results closely matching the simulated results. This RF system’s design provides a compact size, high-gain implantable antenna, high-efficiency rectifier design, simultaneous wireless powering and information delivery, and high overall PTE, making it suitable for leadless pacemakers.