A Broadband Reconfigurable Tri-Polarized Metasurface Antenna Based on Characteristic Mode Analysis

In this letter, a broadband reconfigurable tri-polarized metasurface antenna is proposed. It consists of a dual-polarized antenna and a reconfigurable feeding network. The dual-polarized antenna is designed through characteristic mode analysis. The feeding network equipped with PIN diodes is intended to control the phase difference of two orthogonal linear polarization modes of the dual-polarized antenna, enabling three polarizations: 45° linear polarization (45°-LP), right-handed circular polarization (RHCP), and left-handed circular polarization (LHCP). The measurements reveal −10 dB bandwidths of 25.15% for 45°-LP, 28.10% for RHCP, and 28.57% for LHCP, as well as 3 dB axial ratio bandwidths of 23.96% for RHCP and 23.54% for LHCP. The peak gains of the antenna are 9.7 dBi for 45°-LP, 8.66 dBic for RHCP, and 9 dBic for LHCP.