A Miniaturized UHF-Band Rectenna for Power Transmission to Deep-Body Implantable Devices

Abstract

This paper presents the design, simulation, and fabrication of a 50 Ohm miniaturized rectenna for wireless energy harvesting for leadless pacemakers. The paper evaluates the performance of each section separately and also while cascaded. The system is designed to work at ultra-low RF input power. When the rectenna is placed 5 cm away from the body surface in simulations, the amount of received power is approximately −20 dBm. The proposed antenna is a miniature spiral PIFA with circular polarization at 673 MHz. The measured results, in and outside sheep’s fat tissue, show that about 15 MHz bandwidth can be realized with \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}$\vert S 11\vert $ \end{document} below −10 dB and an axial ratio below 3 dB. Two types of rectifiers are fabricated and compared to choose the best one for such a system. Then, unlike most other researches which selected the doubler rectifier structure, this paper uses a single-diode rectifier structure at this power level. The rectenna can be encapsulated in a cylinder with a radius of 5 mm and a height of 3.2 mm. The efficiency of the rectenna reaches 40% at −20 dBm input power.

A metamaterial unit-cell based patch radiator for brain-machine interface technology

“…3 shows the geometry of the antenna, which is designed on an FR-4 substrate with a relative permittivity ( ) of 4.3 and a loss tangent (tanδ) of 0.025. This substrate is cost-effective and readily available, making it a suitable choice for implantable antenna applications [ [22] , [23] , [24] ]. The total substrate thickness is 1.5 mm, including copper cladding on both sides, each with a thickness of 0.035 mm.…”

Applications of Microwaves in Medicine

“…A planar spiral inverted-F antenna with circular polarizations at 673 MHz for a leadless pacemaker that could be implanted in the right ventricle of the heart was demonstrated [153]. The antenna had a diameter of 5 mm and a height of 3.2 mm.…”

Battery‐Free and Wireless Technologies for Cardiovascular Implantable Medical Devices

“…Another work in the study of far‐field RF powered leadless pacemaker was developed by Abdi and Aliakbarian. [ 197 ] The rectenna system consists of a CP spiral PIFA antenna and a single‐diode detector based on Schottky diodes, and then measured in a three‐layer tissue model. This system achieved a 40% RF‐DC power conversion efficiency and measured a 0.2 V DC output voltage from an input power level of −20 dBm.…”