Fast coding method of metasurfaces based on 1D coding in orthogonal directions

Fast coding method of metasurfaces, based on 1D coding in orthogonal directions, is proposed in this paper. For the previous designed coding metasurfaces with M × N coding sequence, all the M × N codes need to be optimized as a whole, so that the optimized efficiency and flexibility are limited. In this regard, the coding metasurfaces are achieved via only designing the 1D coding sequences in orthogonal directions, and the coding sequences in the 2D plane can be derived by a binary addition algorithm of the two coding sequences. That means, for the M × N coding sequence, the number of coding elements that need to be optimized will be reduced from M × N to M + N. Thus, a faster optimizing method for coding metasurface design will be realized. To validate the method, 16 × 16 coding metasurfaces were designed by optimizing only two 1 × 16 random coding sequences. Both the simulation and experimental results of the designed coding metasurface demonstrated the coding metasurface design method and their excellent performance on mono-static and bi-static radar cross section reduction, which provides a more efficient coding method that allows more flexible manipulation of EM waves.