Three-dimensional finite-difference time-domain algorithm for oblique incidence with adaptation of perfectly matched layers and nonuniform meshing: application to the study of a radar dome.

The three-dimensional finite-difference time-domain (3D-FDTD) method is developed and implemented in the case of oblique incidence in order to study biperiodic structures that are finished according to the third direction. The perfectly matched layer (PML) is adapted to the developed algorithm. The electromagnetic fields of Maxwell's equations in the main grid and in the PML media are transferred from the E-H domain to the mapped P-Q domain. The modified Maxwell's equations are implemented by the split-field method (SFM). Several tests are made and presented in order to verify and demonstrate the accuracy of our codes. The obtained results are in good agreement with published ones obtained by other methods. The originality of this paper comes, first from the fact that it brings a complete development of the used algorithm, and second, from the study of the spectral response of a radar dome based on annular aperture arrays perforated into a perfect conductor plate.