Near field GRECO by PO and PTD

Graphical electromagnetic computing (GRECO) is one of the valuable methods for computing the Radar cross section (RCS) of complex radar targets in high frequency region. But the classical GRECO is usually used for analyzing the target's far-field scattering characteristics. In many practical applications, the far-field condition is not satisfied and it is necessary to compute the target's near-field RCS. Based on the Physical optics (PO) and the Physical theory of diffraction (PTD), the near field GRECO is obtained by modifying the classical GRECO. Numerical results based on near field GRECO are obtained and discussed. Two examples are given for the validity of this method.