Dual-Polarized Dual-Band-Notched Frequency-Selective Absorber With High Design Freedom

A dual-polarized frequency selective absorber (FSA) with dual notch bands is proposed in this letter, in which the lower notch-band and upper notch-band can be adjusted independently and mechanically. The proposed design is a dual-layer structure consisting of two dielectric substrates with etched metal patterns, separated by an air layer in the middle. A bowtie-shaped metal array on the top layer provides broadband absorption. The dual-band-notched with high design freedom property is achieved by dual square loops with parasitic L-shaped elements on the bottom layer and the U-slot etched on the bow-tie-shaped metal pattern. A prototype of FSA exhibits good absorption from 4.58 to 6.8 GHz, 8.52 to 12.5 GHz, and 13.73 to 15.15 GHz, whereas two typical reflective bands are obtained from 7.11 to 7.66 GHz and 12.95 to 13.59 GHz. The center notch-frequency tunable range is from 6.88 to 7.78 GHz and 12.05 to 13.36 GHz, for the lower and upper notch, respectively. Furthermore, an equivalent circuit model is presented. Good agreement is obtained among simulation results, circuit analysis, and final measured response.