Ultra-Low Input Power Drivable IoT Wireless Sensor using Energy Harvesting from 2.45 GHz Wi-Fi

This letter implements an ultra-low-power IoT wireless sensor driven by energy harvesting (EH) from 2.45 GHz Wi-Fi and verifies its performance. First, a planar Yagi-Uda antenna was used to extend transmission distance, and its maximum gain was 12.2 dBi. Next, a high-conversion-efficiency rectifier was implemented using surface-mount components to achieve ultra-low input power operation and achieved 15.7% conversion efficiency at −20 dBm input power. Finally, connecting these components to the sensor module enabled sensor operation at a distance of 3.0 m from the Wi-Fi router. This shows that the proposed IoT wireless sensor offers high flexibility and enables semi-permanent operation.