COMMENT ON "A WIDEBAND WIDE-ANGLE ULTRA-THIN METAMATERIAL MICROWAVE ABSORBER"

In the recently published article, Sood and Tripathi (Progress In Electromagnetics Research M, Vol. 44, 39–46, 2015) proposed a wide-angle ultra-thin metamaterial absorber structure for wideband applications. The reported unit cell was shown to have simulated wideband absorptivity FWHM bandwidth of 1.94 GHz, i.e., from 5.05 GHz to 6.99 GHz. In this article, we prove that the reported structure is not an electromagnetic wave absorber. For the reported structure, we find that absorption is less than 22.3% over a operating bandwidth of 4 GHz to 8GHz. It is demonstrated that the strong absorption was caused due to ignorance of cross-polarization effect rather than true absorption as they claimed.