Polarization-insensitive frequency selective rasorber with broad absorption band and two-sided transmission bands

Abstract

In this study, a compact and polarization-insensitive frequency selective rasorber (FSR) is proposed with dual transmission bands located at the two sides of a broad absorption band. The proposed FSR is a two-layer structure designed by combining the Jerusalem cross based dual bandpass frequency selective surface (FSS) with a broadband resistive square loop absorber, such that both the absorption and transmission characteristics are retained. The proposed FSR has a thickness and size of 0.09λL and 0.026λL2, respectively at the lowest frequency of −10 dB reflection (1.97 GHz). The dual transmission bands are obtained at 2.1 and 8.8 GHz with an in-between absorption band ranging from 3.6 to 7.4 GHz (69.09%). The working principle of the proposed FSR is analyzed using an equivalent circuit model. Furthermore, a range of lower and upper transmission bands with respect to the absorption band is determined by carrying out the parametric studies on the geometrical parameters of the bandpass FSS. A prototype of the proposed FSR consisting of an array of 10 × 10 unit cells is fabricated and the results are experimentally verified. © 2022 Wiley Periodicals LLC.