Reflectivity calculation of a periodical-patch-loaded absorber by the FD-TD method

An objective of this paper is to show low reflectivity of a lossy material with periodical metal patches on the surface by FD-TD computations in addition to experiments. Symmetry conditions based on image theory have been introduced to reduce the computational volume. A uniaxial perfectly-matched-layer (UPML) is used as an absorbing boundary condition, which also reduces computer memory and calculation time. By the computations and experiments, the absorber of this kind is proved to have low reflectivity as a viable microwave absorber. It features potential versatility of design.