An ambient RF energy harvesting and backscatter modulating tag system enabling zero-power wireless data communication

This paper describes an Internet of Things (IoT) tag using an RF energy harvesting and a backscatter wireless communicating system in ambient wireless network environment. We propose a method to transmit data from the tag to Wi-Fi device without power consumption using Wi-Fi signal. This tag system is composed of RF energy harvesting module, backscatter communicating module and sensor. This tag operates to generate power from wireless signal and to transfer date by modulating the receiving sensitivity of Wi-Fi packet. We implemented the zero-power communication tag and tested in Wi-Fi network. As a result, an output voltage above 0.9 V for operating the tag is obtained starting from a received power of about -16 dBm. The maximum power conversion efficiency reaches 25% at 2.4 GHz band. At the communication test, the data transfer rate is achieved 30 kbps at 3 m distance between Wi-Fi devices.