Circular polarizer based on chiral twisted structure

A planar chiral structure is presented in this paper, which is based on a twisted double split-ring resonator (DSRR). As a polarizer, the structure can convert a normally incident linearly polarized wave into a nearly pure circularly polarized wave. The ratio of the transmitted waves with different circular polarization can reach more than 30 dB. Both simulations and measurements verify our design at microwave frequencies. A noticeable advantage of this polarizer is that the size of each unit cell in this structure is extremely small compared with the wavelength in all three dimensions. This structure may be applied in the field of EMC when measurements involving polarization are needed.