Circularly polarized metasurface antenna based on characteristic mode analysis for microwave energy harvesting

In this paper, a circularly polarized metasurface antenna for microwave energy harvesting (MEH) is proposed. First, a 4 × 4 metasurface is analyzed and integrated with the microstrip slot based on characteristic mode analysis for broadband, low profile, and high gain metasurface antenna. The measured results show that the impedance bandwidth of the metasurface antenna is 1.82 GHz, the 3 dB axial ratio bandwidth is 0.96 GHz. Subsequently, a wideband rectifier for C-band is fabricated and measured according complex impedance compression theory. The frequency of efficiency >50% is from 5.1 to 6.3 GHz with 17 dBm input power. Finally, the novel antenna and rectifier are connected as rectenna for MEH, which shows great potential due to the tunability of the polarization mode (right-handed CP [RHCP]/left-handed CP [LHCP]) and the flexibility of the structure.