Comment on "a compact ultra-thin ultra-wideband microwave metamaterial absorber"

In the recently published article, Ramya et al. (Microw Opt Technol Lett. 2017;59:1837-1845. https://doi.org/10.1002/mop.30636) proposed asymmetrical metamaterial absorber structure for wideband applications. It was shown that, the reported structure has wideband absorptivity (above 85%) from 10.36 to 16.67 GHz. It is demonstrated in this article that, the reported unit cell is not a metamaterial electromagnetic wave absorbing structure. It is found that, peak absorptivity is 37.6%, 26.5%, and 28.6% at frequencies 10.5, 13.9, and 16.2 GHz, respectively. The strong wideband absorption caused in the original article is due to ignorance of cross-polarized reflections in the calculation of absorbivity rather than true absorption as authors claimed.