Design of Ultrabroadband Metamaterial Absorber With Angle-Insensitive Characteristics Covering the L, S, C, X, and Ku Bands

This letter presents an ultrabroadband metamaterial absorber with angle-insensitive characteristics covering the L, S, C, X, and Ku bands. The proposed metamaterial absorber achieves wave-absorbing properties through the applications of a cross-shaped substrate printed with high-resistance carbon paste and a frequency-dispersive magnetic material (FDMM). Under the combined effect of the two substructures, the absorber realizes an ultra wide absorption band from 0.84 GHz to 20 GHz with at least −10 dB reflectivity. In addition, the proposed composite metamaterial absorber shows a wide-angle absorbing performance for both TE and TM polarized waves, and the angular stability is up to 60° for TM polarization. With the application of the FDMM, the thickness of the metamaterial absorber is limited to 26.5 mm ($0.074\lambda _{L}$). A prototype is fabricated and measured, and the measurement results agree well with the simulation.