LAUSR

In this paper, a metasurface superstrate-inspired broadband circularly polarized (CP) printed monopole antenna is investigated. To achieve broadband circular polarization and directional radiation pattern, a circle-shaped monopole radiator with asymmetrical staircased partial ground loaded with metasurface is introduced. It is fed by a 50-Ω microstrip feedline and is fabricated on an FR4 substrate, having overall dimension of 1.25λ0 × 1.66λ0 × 0.02λ0 at f = 5 GHz. The metasurface antenna exhibits a measured impedance bandwidth of 5GHz (1.85–6.85 GHz, 114.9%), axial bandwidth of 910 MHz (4.09–5 GHz, 20.02%) with average CP antenna gain of 6.82 dBic, directional radiation pattern and consistent antenna efficiency of > 85.65% in the desired frequency bands. Time domain characteristics, i.e., group delay is obtained within 2 ns in the operating frequency bands. Due to its design process and attainment of broadband CP, higher antenna gain, and directional radiation pattern in the broadside direction, it is extended for RF energy harvesting. The proposed metasurface antenna is integrated with a rectifier circuit, where RF-to-DC conversion efficiency (η0) and DC output voltage (Vout) are analyzed by using ADS circuit solver.