Comments on “An Ultrathin and Ultrawideband Metamaterial Absorber and an Equivalent-Circuit Parameter Retrieval Method”

Recently, de Araújo et al. have erroneously interpreted a linear reflective polarization converting metasurface as an ultrathin and ultrawideband metamaterial absorber. We have shown that an incident electromagnetic wave is strongly reflected in its orthogonal polarization state. Furthermore, we discovered that the absorption rate of the absorber proposed by them was incorrectly calculated due to the overlooking of the cross-polarization reflection component.