Dual-Polarization Frequency-Selective Rasorber With Independently Controlled Dual-Band Transmission Response

This letter presents a dual-polarization frequency-selective rasorber (FSR) with independently controlled dual-band transmission response. The rasorber consists of a lossy layer and a lossless layer. These two layers are separated by an air gap. The upper lossy layer is constructed by four square rings with two stubs, which realizes the two-band transmission response. Frequencies of the two passbands can be independently controlled by changing the lengths of the two stubs individually. The four square rings are connected by a rhombus metallic strip inserted with four resistors producing good absorptivity. As to the bottom frequency-selective surface layer, two square slots are chosen which can realize the same two transmission bands as the upper layer. Equivalent circuit model is also constructed to explain the performance of the proposed FSR. Simulation shows that low insertion losses of 0.39 and 0.64 dB under TE polarization and 0.40 and 0.66 dB under TM polarization are obtained at 8 and 11.9 GHz, respectively. The band with reflection coefficient lower than -10 dB covers 5-12.8 GHz. Prototype of the proposed FSR is fabricated and measured, which shows a good agreement with the simulated results.