Design of a rectenna for energy harvesting on Wi-Fi at 2.45 GHz

Abstract

This research presents the design of a rectenna to harvest electromagnetic energy from Wi-Fi at 2.45 GHz. Tuning techniques were applied on the dimensions of the elements of the rectenna in order to improve its performance. The antenna and the low pass filter were characterized according to their dimensions. Tuning the antenna, S11 magnitude was improved from −9.98 dB on the calculated antenna to −24.12 dB, and the gain was increased in 1 dB. Using the tuned low pass filter, the matching impedance was enhanced with an SWR equal to 1.126. For the rectifier, a single diode and a voltage doubler were evaluated, obtaining a maximum RF to DC conversion efficiency of 31.93% and 45.66% respectively at 20 dBm. The minimum input voltage of the DC-DC boost converter limits the maximum distance between the rectenna and the RF source, to 42 cm for the single diode and to 80 cm for the voltage doubler. It was concluded that the rectenna with doubler configuration offers better output response than the single diode rectifier. The tuning techniques on the design space were effective to enhance the performance of the elements of the rectenna