Fast Analysis Method for Far-Field Scattering Characteristics of Coding Metasurfaces Based on the Equivalent Source Principle

Coding metasurfaces consist of multiple elements with distinct phase (or amplitude) responses. By manipulating the spatial arrangement of these elements, electromagnetic (EM) waves can be flexibly manipulated to achieve various functionalities. To efficiently and accurately calculate the far-field scattering characteristics of coding metasurfaces, some studies have proposed a far-field calculation method based on the equivalent source principle. This method reconstructs the far-field scattering pattern of the metasurface using the total radiation fields generated by the equivalent sources of its elements in space. On this basis, this paper proposes an improved equivalent source method featuring a novel extraction model. Compared with existing methods, it effectively enhances computational accuracy while maintaining high computational efficiency. Comparative analyses against traditional far-field synthesis methods, existing equivalent source methods and full-wave simulation methods, together with experimental measurements, fully verify its excellent performance in both computational efficiency and accuracy.