Wideband ultrathin and polarization insensitive metamaterial absorber for Ku-band applications (original) (raw)
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Journal of Applied Physics, 2020
In recent research published by Chetan et al. [J. Appl. Phys. 126, 175104 (2019)], a wideband metamaterial absorber for Ku and K band applications was presented. In this article, the electromagnetic absorption of more than 90% has been claimed over a large band of frequencies from 14.44 GHz to 27.87 GHz, achieving a bandwidth of 13.43 GHz. In this comment paper, we proved that the authors did not consider the cross-polarized component of the reflected wave while calculating the absorption index of the proposed structure. The structure, in practical, absorbs even less than 20% of the incident electromagnetic energy within the claimed band while the other energy is reflected back in the form of 90°rotating electric field with respect to the incident field. The subject metamaterial "absorber" can be seen as an efficient cross-polarizer having a polarization conversion ratio above 95%.
A compact wideband metamaterial absorber for Ku band applications
Journal of Materials Science: Materials in Electronics, 2020
A compact wideband metamaterial absorber (MA) for Ku band applications is presented in this paper. Ku band is a part of a microwave frequency spectrum ranging from 12 to 18 GHz. The proposed MA absorbs incident wave from 11.39 to 20.15 GHz with a bandwidth of 8.76 GHz which fully covers the Ku band. The proposed structure is compact having an overall dimension of 10 mm × 10 mm. The structure is fabricated on theFR 4 substrate and the simulated result is carried using ANSYS HFSS 19.1. The absorption mechanism is illustrated by calculating effective electro magnetic (EM) parameters (eff & eff). Current distribution is also plotted in support of absorption mechanism. The structure is also examined at different angles (0 0-90 0) for the oblique and normal incident. The proposed MA is tested inside the Anechoic Chamber and it was found that simulated and measured result is close to each other with variation within the tolerance limit. At last comparison of the proposed MA is done with already reported MA. MA presented in this paper finds applications for satellite communication radar surveillance and other defense applications.