Study On The Ambient RF Energy Harvesting System Based On The FSS Of Self-Rectification

With the advent of the Internet era, a variety of sensors are more and more widely applicated in our real life, and they make the RF signal more intensively existing in the surrounding environment. These modern trends have provided a advantageous condition for the collection of RF energy. The traditional battery supply device has shown more and more defects, such as the volume and weight, service life,inconvenience in replacement and environmental problems. Therefore, under the conditions of this background and the actual needs, the collection of RF energy as a new way to get energy supply has attracted more and more attention.In this paper, research work focuses signal the collection of RF energy on the environment of WiFi.Utilizing the derivative structure of Frequency Selective Surface as a receiver of RF energy harvesting,it has many advantages: wider reception band, without a matching circuit, the superposition of energy and so on.Based on the electromagnetic theory and simulation to obtain a new antenna circuit unit structure of energy harvesting system, the physical preparation and test show that at the distance of the transmitter antenna 10 cm, one receiving plate can receive the voltage up to 9V, and the reception of the three receiving plates is up to 14 V from the signal, at the same time its frequency is 2.45 GHz and power is 20 dBm.We had selected the model of BQ25504 chip as the core chip of energy management module to designe and fabricate the energy management module of this system. Then import some different power of the small signal to record its output, and we had obtained the result of working efficiency that it could reach more than 66% by the ratio of input and output. Then we had tested the whole system: utilizing the radio frequency generator to transmit the power 20 dBm, 2.45 GHz frequency band signal, the super capacitor can store energy 1.97 J after collecting 20 minutes at distance of 5cm from the transmitting antenna. In addition, with the environment of ordinary wireless router, this antenna circuit of energy harvesting system can collect the voltage up to1.407 V in the case of no loading. Therefore it has a certain practical value.