Numerical experiments of a periodical-patch-loaded absorber by FDTD computation

In spite of the reflective or scattering nature of metal, a new type of microwave absorber which has periodical metal patches on the surface has been shown to have null reflectivity at a frequency. Several features of this absorber were found by numerical experiments using the FDTD method. There exist many answers to the dielectric constants of the absorber and patch structures for null reflectivity at a frequency. The frequency of null reflectivity largely shifts with the variation of the patch structure. A lot of measurements have also qualitatively supported these computational results which suggest that the metal patches are considered to work as capacitors like artificial dielectrics. An absorber of this kind features a versatile design and the possibility of extreme thinness.