Study on projection error of equivalence principle algorithm

Based on Huygens´ principle, the equivalence principle algorithm can decompose a large computational domain into several subdomains and model electromagnetic phenomenon efficiently. This paper analyses the numerical projection error of the equivalence principle operator (EPO), i.e., the error of the scattered equivalent currents on the equivalence surfaces projected from the currents inside the surface. Numerical studies show that the accuracy of the equivalent magnetic current on the equivalence surface and its far field radiation depend on the shape of the scatterer, and the error convergence rate is usually faster for spherical equivalence surfaces than cubic ones. Therefore, properly choosing the shape of equivalence surfaces according to the shape of the inside scatterers and the position of the observers can improve the accuracy of the equivalence principle algorithm.