Investigation of a Broadband Circularly Polarized Printed Monopole Antenna for RF Energy Harvesting Application

A superstrate-loaded broadband circularly polarized (CP) printed monopole antenna is evaluated for the RF energy harvesting application. For achieving broadband CP traits, enhanced antenna gain and strong directional pattern with wide 3-dB angular beamwidth, circular-shaped monopole having asymmetrical staircased ground plane loaded with PEC superstrate is considered. It is fabricated on the FR-4 substrate with dimension of $1.25\lambda_{\mathrm{o}}\times 1.66\lambda_{\mathrm{o}}\times 0.02\lambda_{\mathrm{o}}$. The proposed prototype exhibits a measured IBW of 5.62 GHz (1.3-6.92 GHz, 136.8%) with ARBW of 1.55 GHz (4.04-5.59 GHz, 32.22%), antenna gain > 6.5 dBic, directional pattern with improved front-to-back ratio (FBR), antenna efficiency > 85% in its operating bands (sub-6 GHz).