Ism Band Rectenna Using a Ring Loaded Monopole

This paper proposes a rectifying antenna (rectenna) for operation in the ISM (Industrial, Scientific and Medical) band centered at 2.45 GHz. It consists of a modified circular monopole loaded with a rectangular ring and a half-wave rectifier. Numerical and experimental data are reported and discussed. From measurements, it is demonstrated that, when the power density incident on the monopole is 155 μW/cm2, the device here presented exhibits values of the RF-to-DC conversion efficiency higher than 30 % in the frequency range 2.35-2.5 GHz with a maximum of about 50 % at 2.45 GHz.