Multi-layer Frequency Selective Rasorber with Wide Bandwidth using 8-shaped Resonators

In this paper, an ultra-wideband frequency selective rasorber (FSR) with both broadband absorption and transmission is presented. The absorber consists of two lossy layers featuring graphene resistance films, accompanied by a third-order Frequency Selective Surface (FSS). Incorporating clamp-shaped and 8-shaped parallel resonators within each lossy layer enables the realization of an almost transparent transmission window. The FSR showcases absorption bands with reflections below -10 dB across 2 to 7.4 GHz and 13.5 to 18 GHz. In the X-band, it exhibits transmissive behavior, particularly within a 20% fractional bandwidth range from 8.6 to 10.6 GHz, achieving transmission loss below 1 dB.