Ultra-wideband Frequency Selective Absorber with Dual Independent Notched Bands

A dual-layer frequency selective absorber with two adjustable notched bands is proposed to realize out-of-band RCS reduction in this paper. Two notch bands are obtained by two circular ring resonators at top of the lossless layer respectively. The structure at the top of the lossy layer loaded with lumped resistors realizes the ultrawide absorption band. By controlling the dimensions of two resonators geometrically, the two notch bands can be adjusted respectively.