Diffraction of an electromagnetic beam by planar structures

Electromagnetic beam, which is the solution to Maxwell's equation rather th an paraxial wave equation, is simulated by FDTD method directly. Electric a nd magnetic field components are displayed pictorially. Then the diffractio n of an electromagnetic beam pulse by a planar structure containing conduct or and dielectric, which may be periodic structure or not, is analyzed. The power transmittance of the structure is calculated to show its frequency r esponse characteristics. The fields in time domain near the structure, whic h shows the diffraction by the structure obviously, are presented pictorial ly too.