Evaluation of Space Time Beamforming Algorithm to Realize Maintenance-Free IoT Sensors With Wireless Power Transfer System in 5.7-GHz Band

Smart factories can be realized by effective and flexible placement of IoT sensors in all equipment. Even though many energy-efficient solutions are aimed at enhancing IoT sensor lifetimes, additional maintenance is required to replace batteries after a stipulated amount of time. To overcome this burden and realize maintenance-free IoT sensors, we evaluate a space-time beamforming (STBF) algorithm based on microwave power transfer in a 5.7-GHz band and compare the required transmit power with typical beam-splitting algorithms, namely Max-Sum and Max-Min. We also experimentally evaluate the usability of STBF and verify the required transmit power to realize maintenance-free IoT sensors.