Parametric Study of an Ultrathin Flexible Wideband Absorber for K Band

Abstract

This paper presents the parametric study of a low-cost, flexible, ultrathin absorber comprising a dual concentric ring shape frequency selective surface (FSS). The absorber structure is incorporated with periodic dual concentric ring as FSS on a photo paper substrate material backed with a copper foil ground plane. Periodicity of the unit cell is 6.6 mm which is only 0.56λ0 and all-inclusive thickness of the absorber is 0.15λ0, where λ0 is free space wavelength at 25.87 GHz which is centre frequency. The fractional bandwidth (FBW) of the proposed absorber is 74.8 % at -10 dB reflection which covers not only complete K-Band but also higher range of Ku- Band and lower range of Ka- Band. The proposed absorber behaves uniformly at different angle of polarization. Effect of variation in different parameters of FSS like periodicity of unit cell, thickness of the substrate, inter element spacing, width of the ring, have been examined and optimized using a high frequency structure simulator software (HFSS).