FDTD INVESTIGATION ON BISTATIC SCATTERING FROM A TARGET ABOVE TWO-LAYERED ROUGH SURFACES USING UPML ABSORBING CONDITION

This paper presents an investigation for the electromagnetic scattering characteristic of the 2-D infinitely long target located above two-layered 1-D rough surfaces. A finite-difference time-domain (FDTD) approach is used in this study, and the uniaxial perfectly matched layer (UPML) medium is adopted for truncation of FDTD lattices, in which the finite-difference equations can be used for the total computation domain by properly choosing the uniaxial parameters. The upper and lower interfaces are characterized with Gaussian statistics for the height and the autocorrelation function. For the composite scattering of infinitely long cylinder and underlying single-layered rough surfaces as an example, the angular distribution of scattering coefficient with different incident angles is calculated and it shows good agreement with the numerical result by the conventional method of moments. And the influence of some parameters related to the two-layered rough surfaces and target on composite scattering coefficient is investigated and discussed in detail.