A novel ultra-wideband rasorber based on triple lossy layers

Abstract By surpassing the limitations of transmission efficiency found in traditional double-lossy-layers rasorbers, a novel rasorber with three distinct lossy absorption layers is presented, offering low insertion loss and ultra-wideband bandwidth. Compared to conventional rasorbers which have non-negligible insertion loss and large thickness, our design extends the bandwidth in the higher frequency band without increasing thickness, while maintaining high transmission efficiency. To further broaden the absorption band, an additional lossy layer resonating at lower frequency band, with high transmission above the resonance frequency was incorporated into the previous design. The composite structure is developed by the equivalent circuit model whose results are in accord well with the simulation results. The simulated results demonstrate that an insertion loss of 0.37 dB at 10 GHz, and a 159.5% 10 dB reflection reduction bandwidth from 2.04 to 18.05 GHz are attained under normal incidence. A manufactured specimen of the proposed structure is measured to validate our design.