Dual-band polarization angle independent 90° polarization rotator using twisted electric-field-coupled resonators

A bilayered chiral metamaterial is proposed to realize a dual band polarization angle insensitive 90 degrees polarization rotator. The unit cell of the chiral metamaterial is composed by twisted electric field coupled resonators in four-fold rotation symmetry. The simulation and measured results show that this device can work in dual band with an extremely low loss and polarization conversion ratio of more than 99%. The study of the current and electric fields distribution indicates that the cross-polarization transmission is due to both the electric coupling and the magnetic coupling. (C) 2014 AIP Publishing LLC.