“…With the development of electronic devices and radar systems, the electromagnetic (EM) environment becomes more increasingly complex than ever before [ 1 , 2 , 3 ]. In complex and various EM environments, the analysis of scattering problems, the improvement of radar systems and the recognition of hidden targets have become frontier science in recent years [ 4 , 5 , 6 , 7 ], including electronic countermeasures, electronic support and so on [ 8 , 9 ]. When solving scattering problems, the investigation of the scattering properties is regarded as one of the most important aspects [ 8 , 9 , 10 ].…”