FDTD method has been widely studied and applied in the recent years. It has many advantages over other numerical methods. When CAD technique gets involved

FDTD method makes a large pace toward its practicableness. In this paper

we introduce how to use CAD software to generate the original geometreic-electromagnetic parameter description file provided to the FDTD calculation code to solve the electromagenetic scattering problem of those objects with complex geometric shape and electromagnetic parameter distribution. Using this technique

we can get the geometric-electromagnetic parameter description file from the design drawing

sectional drawing or other ways of description of the objects. As an example

a kind of plan’s RCS in the resonance frequency was calculated.