Study of the efficiency of rectifying antenna systems for electromagnetic energy harvesting

Abstract

The focus of this work is on wireless power transfer via electromagnetic radiation. An RF energy harvesting device consists of three primary subsystems. The first subsystem is the receiving antenna, which is responsible for capturing all of the RF energy that will later be used to power the integrated embedded system. The second main subsystem is the rectification circuitry, which efficiently converts the input RF power into DC output power. The third subsystem is a DC/DC converter (regulator), which is responsible for maintaining a constant output DC voltage suitable to power the electronic circuitry following the harvester for a wide range of input DC voltage variation. Each one of these three subsystems is integral to the operation of the entire harvester system. A 2.45 GHz electromagnetic energy harvester is proposed. The presented work consists of a) design and characterization of a circularly polarized aperture coupled patch antenna, b) performance study, optimization and prototype characterization of various diode rectifier circuits and c) design and implementation of an evaluation board for a commercial DC voltage regulator.