Dual-Polarized Metagrating for Controlling Diffraction Patterns in Orthogonal Planes

Abstract

Metagratings (MGs), sparse distribution of periodic structures, enable the control of anomalous beam diffraction. However, most of the MGs reported so far are polarization-sensitive structures that only support excitation with a certain single polarization. Here, dual-polarized MGs (DPMGs) composed of cross-shaped unit cells, which exhibit independent responses to $x$ - and $y$ -polarized waves simultaneously, are proposed. By validating different load-impedance densities perpendicular to the two incident polarization directions, the DPMGs can achieve energy distributions between multiple propagating diffraction orders in two planes. To validate the proposed design, two proof-of-concept MG samples are fabricated and tested, and the experimental results are found to be consistent with the simulated ones. Under orthogonal polarized incidences, we validate a first scenario where the beam is reflected in the +1st diffracted order in both the planes. Then, a second scenario is considered, where beam-splitting between +1st and −1st diffracted orders in one plane and reflection in the +1st order in the other plane are realized. These results suggest the use of DPMGs for a broader range of applications such as multichannel information processing, dynamic dual-polarized antennas, and radar systems.