A simple wideband electromagnetically fed circular polarized antenna for energy harvesting

Abstract

A novel of wideband circular polarization (CP) antenna with high gain that is suitable to harvest energy is proposed. In this article, our objective is to design an antenna that is capable of fully harvesting ambient RF energy. A survey on the feasibility of scavenging for RF energy was conducted through power density measurement in an urban area. Using the results, a CP antenna was designed to cover the frequency band from the largest RF contributors, ranging from 1.73 to 2.61 GHz in GSM1800, UMTS, WiMAX and the unlicensed industrial, scientific, and medical (ISM) bands. Hence, a simple single feed electromagnetic (EM) coupled circularly polarized antenna with high gain is presented. The wideband CP is achieved by implementing EM coupled feed with a defected ground plane structure. Experimental results showed the antenna achieved an axial ratio bandwidth of 25% with respect to 2.08 GHz center frequency. Furthermore, the antenna exhibits broad impedance bandwidth of 32.77% with the measured peak gain is 8.7 dBic at 2.05 GHz. The proposed antenna structure is simple and low cost with a size of 0.462 λo and wide 22.1% axial ratio bandwidth.