Electromagnetic wave beam manipulator based on an all-dielectric THz coding metasurface.

Abstract

In this paper, we proposed an all-dielectric THz coding metasurface that can effectively manipulate electromagnetic waves. This structure was composed of sub-wavelength coding units with different reflection phases. The encoding unit is composed of a rectangular base with a cross dielectric column. Different encodings were designed by changing the thickness of the X arm of the dielectric column. We designed a variety of coding modes and implemented the modulation of the number of far-field reflection beams and the angle of reflection direction at 0.85 THz by 1- and 2-bit coding. Our theoretical calculations and numerical simulations of the structure suggested that the far-field scattering obtained by full-wave simulation matched the theoretical calculation when the incident direction of electromagnetic wave was perpendicular to the metasurface. We chose all-dielectric materials to design the coding unit due to the low cost, strong corrosion resistance, and low internal electromagnetic loss. As a result, the all-dielectric materials avoided the serious internal loss of metal materials and demonstrated the flexibility to regulate the reflected beam in the THz band to realize abnormal refraction and beam splitting.