A Frequency Selective Surface based Polarization-Independent Band Notched Electromagnetic (EM) Wave Absorber

This work presents an EM wave absorber with a band notch between the absorption band. The proposed work consists of two vertically arranged FSS-based resonators over a common metal on the bottom side. The SMD resistor loaded top FSS pattern offers wide absorption bandwidth, and the bottom FSS pattern provides the band notch between the absorption band. The simulation results show that the proposed structure offers more than 90% absorption in 5.8-12.9 GHz and 14.48-20.8 GHz frequency bands with a reflection notch at 13.5 GHz with a 3dB bandwidth of 500 MHz. The designed structure is also polarization-independent due to the four-fold symmetry inside the resonator. Analysis of the proposed structure's angular stability shows that the presented design is angularly stable up to 50° and 40° for TE and TM polarization, respectively. The proposed structure is compact in nature with the unit cell dimension of $0.19 \lambda_{L} \times 0.19 \lambda_{L} \times 0.12 \lambda_{L}$, where $\lambda_{L}$ is the wavelength's lowest frequency. Due to presence of the notch band along with absorption, this structure can be used for RCS reduction application of antenna where the notch band can be used as reflector of the antenna.