The scattering field of the complex target can be attributed to the combination of the surface and edge, and on the bordering area of illumination and shadow,fast changing phase will cause computing error,and the simple incremental length diffraction coefficients(ILDC) result in low precision.

Physical optics (PO) and physical theory of diffraction (PTD) are utilized to evaluate the scattering from the large bodies with the cracks filled with perfect conductors.

This technique employs the edge-based finite-element method (FEM) to compute the scattering from the cracks, and PO and PTD to compute the scattering from the large bodies with the cracks filled with perfect conductors.

The primary radiation characteristics of open-ended rectangular waveguide with a perforated hole on the broad wall are analyzed by finite difference time domain(FDTD) method and also the secondary radiation characteristics of the reflector antenna are analyzed by physical optics(PO) method and physical theory of diffraction (PTD).

In this paper,the high frequency backscatter field of the rotating skew-plated metal fans are investigated based on PO/PTD(physical optics/physical theory of diffraction) and the method of equivalent currents (MEC) ,in conjunction with the quasi-stationary method.

On the basis of diffraction theory,the wave loads on an submerged floating tunned(SFT) were obtained by the source distribution method.