A Dual-Polarized Frequency-Selective Rasorber With Wideband Switchable Transmission/Absorption Capability

In recent years, switchable frequency-selective rasorbers (FSRs) have been greatly investigated due to their excellent in-band shielding capabilities. However, achieving a switchable wide passband while maintaining a broad low reflection band is difficult in FSR design. In this letter, a dual-polarized FSR with wideband switchable transmission/absorption capability is proposed. The FSR features a three-layer architecture including the non-switchable impedance layer, switchable impedance layer, and switchable frequency-selective surface (FSS). The device can be switched between rasorber and absorber modes by controlling the biasing conditions of the PIN diodes in different layers. Meanwhile, the equivalent circuit model (ECM) is established to analyze the operating principle of the proposed FSR, serving as a critical tool in design. Finally, the full-wave simulation results are verified through fabricating and measuring the prototype of the proposed FSR. Results indicate that the proposed FSR achieves wideband transmission of 23.7% and a low reflection band of 142.5% under rasorber mode, while under absorber mode, the wideband absorption of 138.3% is achieved.