Dual-Band Funny-Face Wi-Fi Energy Harvester for Indoor Battery-less Wireless Sensor

This paper presents a novel compact and dual-band funny-face-shaped Wi-Fi energy harvester to be used in indoor self-powered wireless sensor. The initial circular monopole receiving antenna is slotted to create multiple available current paths, thus achieves dual-band resonance at 2.45 GHz and 5.8 GHz. The feed line of the antenna is also grooved to form a filter, enhancing its harmonic rejection capability. The antenna exhibits multi-directionality, making it suitable for practical use. In our experimentation using the very low power of incident wave (-4 dBm for 2.4 GHz and -7 dBm for 5.8 GHz), the Wi-Fi rectenna possesses an efficiency of 55% and 29% at 2.45 GHz and 5.8 GHz, respectively. This Wi-Fi energy harvester is potential for battery-less wireless sensor application.