Broadband Dual-Polarized Band-Absorptive Frequency-Selective Rasorber Using Absorptive Transmission/Reflection Surface

A dual-polarized broad band-absorptive frequency-selective rasorber (FSR) is proposed in this article. The FSR has a lowpass band with low insertion loss and a broad absorption band. It is a two-layer structure formed by a lossy surface cascaded an absorptive transmission/reflection surface (ATRS), in which the ATRS is constructed by one substrate with a resistive square loop on its top side and a double square loop on its bottom side. The working mechanisms of the proposed ATRS and FSR are completely studied by using their equivalent circuit models. The ATRS retains dual stopbands of the double square loop and suppresses the unwanted transmission pole of the double square loop. Then a broadband absorptive FSR is achieved. A sample of the proposed FSR is fabricated and measured. The measured results show that the proposed FSR has a lowpass band up to 860 MHz (|S
₂₁
| ≥ -1 dB) and a broad absorption band with bandwidth of 95.3% from 3.84 to 10.83 GHz (|S
₁₁
| ≤ -10 dB and |S
₂₁
| ≤ -10 dB).