Compact Broadband Rectenna for Harvesting RF Energy in WLAN and WiMAX Applications

This paper presents a compact broadband rectenna for harvesting RF energy in WLAN and WiMAX applications. A coplanar waveguide (CPW) rectangular monopole antenna loaded with double inverted-L strips is designed as the receiving antenna. By using an inverted-L open circuited stub as an input matching network, a compact rectifying circuit based on the voltage doubler principle is proposed, which has broadband performance. The receiving antenna and the rectifier are simulated using CST and ADS software packages, fabricated using photolithographic technique, and measured. The antenna is operating from 1.83–3.58 GHz (bandwidth of 1.75 GHz), and 5.4–6 GHz (bandwidth 600 MHz). These bands cover different wireless applications such as: GSM 1800, UMTS 2100, IEEE 802.11b&g WLAN systems, 3.5 GHz WiMAX system, and the IEEE 802.11a WLAN system. The antenna gain reaches 4.2 dBi at 5.8 GHz while the radiation efficiency is 99.6 %. The measured rectifier conversion efficiency reaches 29.72 % at 6 dBm input power while the measured total rectenna power conversion efficiency is 27.725 % at a frequency of 3.5 GHz.