Sparsity-driven high-resolution fast electromagnetic vortex imaging based on two-dimensional NCALM

The electromagnetic (EM) vortex wave carrying orbital angular momentum (OAM) has been found great potential to improve radar imaging performance. This paper proposes a novel two dimensional (2D) sparsity-driven high-resolution fast method for EM vortex imaging. The method deals with the 2D signal model for the image reconstruction directly. The superiority is that the memory usage and the computational complexity are much lower than those of the one dimensional imaging method. In addition, we introduce the parameterized hyperbolic tangent function as penalty function for obtaining higher resolution imaging results, and utilize the parameter adjustment method to achieve the sparse solution by gradually decreasing shape parameter. Simulations demonstrate the effectiveness and efficiency of the newly proposed method in EM vortex imaging with high resolution using fewer OAM mode numbers.