Electric toroidal metamaterial for resonant transparency and circular cross-polarization conversion

Electric toroidal dipolar response has been achieved by metamaterial based on sun-like aperture element at microwave frequency. It is confirmed numerically by scattered powers that the electric toroidal dipolar moment dominates over other moments at the corresponding resonance. This proposed metamaterial exhibits resonant transparency under linearly polarized incidence caused by destructive interference between magnetic dipole and electric toroidal dipole. Notably, it also provides circular cross-polarization conversions between left-handed circularly polarized wave and right-handed circularly polarized wave at the same frequency. These properties associated with elusive electric toroidal dipolar moment offer an avenue for various potential applications in microwave devices.