Target Scattering Characteristics under Beam Illumination Based on MoM

In the case of antenna beam illumination, the RCS of the target at different distances from the antenna is calculated by the method of moments. And the calculation results are used to compare with the RCS under plane wave conditions. By analysing the trend of RCS, it is found under what conditions, the plane wave can be approximated as the calculation source. The scattering characteristics of the target in the case of local illumination are also considered. By comparing RCS with different size targets, it is found that the RCS of the partial target can be calculated to approximate the overall target. This conclusion can be used to simplify the calculation of the RCS of the electric large size target.