Design and development of dual-band multi-stage RF energy harvesting circuit for low power applications

This paper presents the design and development of a dual-band multi-stage rectifier aimed at converting far field RF energy into DC voltage at low received power. The designed RF energy harvester consists of a dual-band matching network followed by a 3-stage rectifier which has been designed to work in GSM 900 MHz and Wi-Fi/Wireless LAN (WLAN) bands. It provides a peak conversion efficiency of 80% at 8 dBm received RF power at 915 MHz. The experimental results also show that the proposed dual-band rectifier can harness twice amount of power than single band 915 MHz rectifier. This work further utilizes the above circuit to obtain preliminary results of RF energy harvesting through mobile phones. Mobile phones from two different manufacturers have been used to evaluate the output DC voltage levels obtained through energy harvesting. Measurements were taken during call-establishment phase as well as during call-conversation phase. It was shown that depending on the manufacturer, it is possible to obtain peak average voltages of 1 volt and 0.25 volt in call-establishment phase and call-conversation phase respectively. The prototype has been fabricated on RT/Duroid 5880 substrate and all the simulations have been performed on Advanced Design System (ADS).