Multi-band Tunable Asymmetric Transmission of Linearly Polarized Electromagnetic Waves Achieved by Active Chiral Metamaterial

Recent studies show that chiral metamaterials can be used in the applications such as polarization conversion and asymmetric transmission (AT) without external magnetic field. Here we propose a tunable chiral metamaterial incorporated with active components of PIN diodes for flexible control of asymmetric transmission of linearly polarized electromagnetic (EM) waves at microwave frequencies. We experimentally demonstrate that this structure can realize multi-band tunable chirality, polarization conversion as well as asymmetric transmission for a linearly polarized wave in the microwave region. Our design is a good example of realizing the active control of metamaterials with easy fabricated feature and robust controlled effect, which can be further regulated in a programmable manner.