Wideband Polarization-insensitive Metamaterial Microwave Absorber for S and C Band Application

Abstract

The designing and development of wideband polarization insensitive Metamaterial Microwave Absorber (MMA) is presented in this paper. The proposed unit cell consists of four trapezoidal which is connected to concentric square and cantered square via lumped resistors. The absorber is designed on FR-4 substrate with permittivity 4.3 and thickness 0.256 mm (λ/144). The wideband absorptivity with more than 90 % absorption is obtained from 2.21 GHz to 6.61 GHz having bandwidth of 4.40 GHz. Two distinct absorptivity peaks have been perceived in the range of interest having frequencies at 2.49 GHz and 5.68 GHz with maximum magnitude of 92.50% and 92.14%. The designed absorber is also found to be polarisation insensitive for both TE and TM polarised Electromagnetic (EM) wave up to oblique incidence of about 60°. These two peaks arise because of plasmonic resonance. The fabricated structure is measured inside the Anechoic Chamber, the simulated and measured results are almost similar to each. The proposed absorber structure finds applications for S (2-4 GHz) and C (4-8 GHz) band particularly in defence applications for wideband stealth applications and RCS reductions.