Dual-Broadband Flexible Frequency Selective Rasorber Based on Circular Spiral Resonator

In this paper, we present a dual-broadband flexible frequency selective rasorber (FSR) based on a circular spiral resonator (CSR), composed of the double-layer loss structure and frequency selective structure. The combination of the above two structures makes the whole FSR show the characteristics of a wide passband and double wide absorbing band. Due to the use of a thin dielectric substrate, the overall FSR is flexible. The simulation results indicate that the insertion loss remains below 1 dB within the passband from 8.86 GHz to 10.86 GHz, while the absorption rate exceeds $\mathbf{9 0 \%}$ in the ranges of 2.06 GHz to 7.04 GHz and 13.14 GHz to 18 GHz. At the same time, due to its small period characteristics, it can still maintain good absorption and transmission even at large angle incidence.