This article presents a metasurface absorber demonstrating high absorption performance in the microwave range. The proposed absorber operates in the \(S-, C-, X-, Ku-,\) and \(K-\) band frequencies, achieving over \(90\%\) absorption at seven different frequency points. The peak absorption frequencies of the absorber are 2.8, 6.32, 9.17, 12.21, 14.4, 17.3, and 19.5 GHz, with absorption performances of 92.6, 91.7, 93, 96.3, 97.4, 98.3, and \(99.8\%\) , respectively. The metasurface is printed on an economical FR-4 substrate, and the unit cell size is designed to be very thin, measuring \(0.146\lambda _o \times 0.146\lambda _o \times 0.0093\lambda _o\) in terms of the maximum wavelength. The design consists of four different resonators, each with a symmetric structure, which makes the design polarization insensitive for both transverse electric (TE) and transverse magnetic (TM) modes. When examining the absorber’s performance at oblique angles, it was observed that, except for the third peak point, the other six peak points maintain absorption performance above \(80\%\) up to 45 degrees. At the third peak point, the absorption performance is around \(65\%\) at 45 degrees. To better understand the absorption mechanism, the characteristic impedance, permittivity, permeability, surface current, electric and magnetic field distribution graphs of each resonator were analyzed. To verify the reliability of the simulation results, the design’s equivalent circuit model (ECM) was created using the ADS circuit simulator. The monostatic RCS of the design was investigated, and it was found to exceed 7 dBsm at the absorbing frequencies. Additionally, a prototype of the proposed special metasurface absorber was fabricated, and experimental absorption performance was obtained. The prototype measurement results were found to be quite consistent with the simulation results.
