The new analysis to near field scattering characteristics of the complex target

The near-field scattering of complex targets is a very useful characteristic parameter for theory analysis and measurement. With the MLFMM, the near-field scattering of a typical ship have been simulated to analyze the near-field scattering characters of the ship in free space in different detecting distances and frequencies. And the results show that with reduction of range, the difference between results of near-field and far-field scattering become very prominent. However, the difference between their average results is relatively small. As a result, it seems that the required distance between antennas and ships for test may be far less than traditional far-field distance. Then, we have proposed a new method for quantitative predicting the far-field distance of average base on the imaging theory. Finally, the validation of the new method has been verified by the simulation results.