Dual-band asymmetry chiral metamaterial based on planar spiral structure

A dual-band asymmetric chiral metamaterial is constructed by using two pairs of planar spiral structures with a certain twisted angle. Numerical simulation results show that when a y-polarized wave is incident on the chiral metamaterial the left circularly polarized wave is emitted at 12.25 GHz and 15.57 GHz, while right circularly polarized wave is excited at 13.9 GHz and 16.86 GHz. The measured transmissions are higher than −2.4 dB, and the absolute values of the transmission differences between the right and left circularly polarized waves exceed 15 dB at the four frequencies, which agree well with the simulated results.