Wideband and function-switchable polarization converter based on multi-mode active metasurface

A linear polarization converter based on multi-mode active metasurface is proposed to achieve wideband/dual-band, function-switch, low profile, filter and reflection, including two slot-loaded right-angle triangular reso-nators connected by two PIN diodes. The switchable function of the linear polarization converter between wideband and dual-band is realized by controlling the OFF/ON states of the diodes. By detailed analysis of the field/current distribution and polarization components in different modes of the multi-mode resonator unit, the filtering characteristic and magnetic-resonant-based polarization conversion mechanism between wideband and dual-band are revealed. A function-switchable filtering reflective linear polarization converter is designed, fabricated, and measured, presenting single bandwidth of 6.43-10.16 GHz, dual bandwidths of 6.08-6.39 GHz, and 11.7-12.54 GHz in the OFF-and ON-state, respectively. In both states, the polarization conversion ratios both exceed 90 %. Results show that the proposed reflective linear polarization converter has excellent switchable function, low profile and filtering linear polarization conversion.