A Self-Powered Environmental Data Sensor Node Based on Efficient RF Power Transfer
Mengxi Yan, Ruiyao Du, Qiulei Huang, Xiaozhou Li, Nan Zhao, Lei Guo, Ke Wu · 2024
This paper introduces a self-powered environmental data sensor node that relies on the collection of radio frequency (RF) energy transmitted by an unmanned aerial vehicle (UAV). A meticulously designed rectifier circuit not only captures RF energy at 433 MHz but also provides feedback of the second harmonic signal at 866 MHz to the UAV. This feedback mechanism enables antenna alignment, thereby improving energy conversion efficiency. The proposed rectifier circuit exhibits a measured RF-DC conversion efficiency of 22.8% and generates a second harmonic power of -39 dBm at an input power of -20 dBm. It is employed to power a microcontroller which coordinates the sensor to periodically collect environmental data, including temperature, humidity, and carbon dioxide concentration. Then the sensing information is transmitted to a mobile terminal using Bluetooth. An antenna calibration experiment was conducted, during which the transmitter successfully received a second harmonic signal of -59.5dBm at a distance of 12 meters from the rectifier. This experiment serves as verification that the proposed rectifier can effectively assist UAVs in achieving efficient wireless power transfer to sensing nodes located at considerable distances.