Rectenna with Enhanced Aperture Efficiency and a Bi-directional Pattern for Ambient RF Energy Harvesting

Abstract

This paper introduces a novel rectenna with a double-sided ground plane microstrip antenna that has a bidirectional radiation pattern for ambient RadioFrequency (RF) energy harvesting. The microstrip antenna has a supplementary slot that enhances the aperture efficiency of a conventional rectangular patch antenna from 50% to 72% in simulation and allows for a high gain bi-directional pattern. With a maximum experimental gain of 7 dBi, the proposed rectenna can capture as much ambient RF power as a patch antenna and rectify it with an efficiency of 25.8% for a $0.15 \mathrm { n } \mathrm { W }/\mathrm { cm } ^ { 2 }$ power density, while being less sensitive to the energy source location. By duplicating the rectenna, two complementary radiation patterns can be obtained allowing incoming RF radiations with four different orientations to be collected.