Wide band metamaterial absorber for Ku and K band applications

This paper presents a very compact simple double square shaped design of a Metamaterial Absorber (MA). The dimension of the square is $1.41×1.41mm2$⁠, and the overall dimension of the unit cell structure is $5×5mm2$⁠. A wideband of absorption is achieved from 14.44 GHz to 27.87 GHz having a bandwidth of 13.43 GHz at $−10$ dB, which covers the Ku (12 GHz–18 GHz) and K (18 GHz–27 GHz) bands approximately. The proposed structure finds application in the field of radar and satellite communications. The full width half maxima bandwidth achieved is 16.39 GHz (from 13.61 GHz to 30.00 GHz). Three absorption peaks are obtained at 16.54, 20.54, and 25.81 GHz with absorptivity of 99.89%, 99.95%, and 99.96%, respectively. The simulation of the proposed MA is carried out using ANSYS HFSSv19.1, and it is fabricated on FR$4$ (Flame Retardant) using a printed circuit board. Analysis is done under both normal incident and oblique incident for different angles. The measured and simulated results for absorption are almost very close to each other with little variation due to fabrication tolerances.