Substrate Material Impact on the Efficiency of RF Energy Harvesting Dipole Antennas

This work presents a comprehensive comparison of the influence of the substrate material on the efficiency of an RF harvesting dipole antenna. A simple dipole antenna was designed as a starting model with capacitive loads on each end, in order to achieve a compact design, tuned at two high RF energy frequency bands of interest according to previous measurements. Two equivalent monopole prototypes were fabricated, one with an FR4 substrate and other with air substrate. With them, the efficiency measurements of these prototypes were carried out through the extended WCap method for ultrawideband antennas. As it is shown, the loss in efficiency in dipole antennas having the dielectric substrate is not as important as it would be expected. On the other hand, they have assembly facilities that make them preferable.