Terahertz materials for energy harvesting rectenna /

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Energy collecting antenna have been studied for over a century. Early work performed by Heinrich Hertz and Nikola Tesla focused primarily on the transfer of energy at low frequency electromagnetic waves. The present work studies the possibility for harvesting electromagnetic energy present on earth from both terrestrial and solar sources. In general the energy density available increases with frequency, peaking around the visible portion of the spectrum. Because of the difficulty of converting high frequency signals, the present focus will be on the intermediate Terahertz range where the power density begins to increase. The goal of this work is to support the viability of an energy harvesting rectenna to collect and convert Terahertz frequency electromagnetic energy. The collection of the energy by an antenna is supported through probing frequency dependent material properties required for designing the device. Modelling of materials sensitive to THz waves is confirmed through spectroscopic measurements of fabricated devices. Device design is further supported by showing the relationship between the measured material properties and conversion, or rectification, efficiency. Finally, the concept is proved through quantitative results of THz rectenna measurements.