A multilayer frequency‐selective rasorber for wideband transmission based on harmonic suppression

To break through the limitation of harmonic loss on transmission bandwidth, a multilayer frequency‐selective rasorber (FSR) for wideband transmission is present in this letter. First, the principle of harmonic suppression implemented by a lossy layer is described and analyzed in detail. Second, based on this lossy layer, an absorption–transmission (A–T) rasorber with harmonic suppression, which can generate a wide passband above the lower absorption band, is achieved. And then, by combining with a transmission–absorption (T–A) rasorber, an absorption–transmission–absorption (A–T–A) FSR with a wide and low insertion loss (IL) passband can be obtained. The simulation result shows that the −1‐dB passband ranges from 7.1 to 17.49 GHz with 84.5% relative bandwidth. Finally, a prototype is fabricated and measured to validate the design.