Design of a hybrid frequency selective rasorber with wide band absorption performance for C, X, and K bands

Abstract

AbstractHybrid frequency selective rasorber (FSRs) composed of hybrid lossy layers and bandpass frequency selective surfaces (FSSs) are proposed in this study, which works as an absorber with absorption bands of 3.34–11.95 GHz and 17.44–24.29 GHz providing the fractional bandwidths of 112% and 33% while reserving a transparent window from 13.75 to 15.32 GHz. The proposed FSR is designed by stacking a hybrid lossy layer and band‐pass FSS. One of the lossy layers is composed of a λ/4 transmission line resonator in the middle of the lumped resistors' loaded bent dipole, which realizes an absorption‐transmission (A–T) frequency response, and the other is constructed by four stripe‐type parallel inductor and capacitor resonators connected to a lumped resistors' loaded circular ring, which realizes T–A frequency response. The bandpass FSS is a three‐tier structure in which the top and the bottom layers are composed of periodical circle patches and the middle layer is composed of circle slots. To explicate the working mechanism of the hybrid FSR, an equivalent circuit model is established, meanwhile, the surface current loss is analyzed. A fabricated prototype of the proposed FSR is assembled and measured to test the simulated frequency response.