# Design of a Polarization-Insensitive and Wide-Angle Triple-Band Metamaterial Absorber
## 3 Analysis and Discussion
The reason for this phenomenon may be that the electromagnetic field vector directions of TM waves and TE waves are perpendicular, and the structures of MMA in the X and Y directions are different. The MMA arranged in a honeycomb shape is compactly arranged in the X direction. In the case of oblique incidence, the electromagnetic response generated by adjacent units will not be greatly affected, while the spacing between adjacent MMA units in the Y direction is larger (nearly 10 mm). Under normal incidence, such an arrangement will not have a significant impact on the absorption efficiency, while under oblique incidence, MMA will not be able to generate a stable electromagnetic response at the original absorption frequency due to its relatively sparse arrangement, thus exhibiting significantly deteriorated absorption characteristics. Figure 9: Comparison of \(S_{11}\) curves from CST and ADS. Figure 10: Absorption efficiency diagrams at different polarization angles and incidence angles: (**a**) absorption efficiency at different polarization angles; (**b**) absorption efficiency of TE waves at different incidence angles; (**c**) absorption efficiency of TM waves at different incidence angles. ferent details and sizes. To analyze the impact of these individual structures on absorption performance, the simulation results of each separate section are compared to those of the complete structure. The corresponding absorption curves and schematic diagrams of these structures are shown in Figure 12.  
As shown in Figure 12, the three structures from the outside to the inside correspond to the three absorption peaks, from low-frequency to high-frequency, respectively, which indicates that the large-sized structure corresponds to the lower frequency absorption frequency point. It can be seen that the absorption near 4 GHz and 14 GHz does not differ significantly before and after separation, while the absorption efficiency at 7.479 GHz, in the middle, drops from 99.3% to 97.5% after separation. This indicates that the absorption efficiency of a single absorption peak does not depend solely on the corresponding structure, and the absorption performance of the middle ring also depends on the coupling between adjacent structures. In addition, the absorption performance of the double-ring structure was compared, as shown in Figure 5:0 There are three combination modes of the double-ring structure, namely, inner-middle, inner-outer, and middle-outer. The inner-middle ring achieves absorption efficiency of 97.9% and 99.03% at 7.384 GHz and 14.813 GHz, respectively; the inner-outer ring has an absorption efficiency of 99.2% at 4.211 GHz and 99.6% GHz at 14.642 GHz; and the middle-outer ring has two absorption frequencies of 4.268 GHz and 7.441 GHz, and the corresponding absorption efficiencies are 99.8% and 99.5%. It can be found that with the change in the combination mode, the absorption frequency and absorption efficiency do not change significantly, which indicates that the coupling between the inner, middle, and outer rings does not weaken the absorption performance. Table 4 compares the proposed triple-band metasurface absorber with the published research results in related fields in recent years. It can be found that the proposed structure is the only absorber that works in the C-band and Ku-band, and the absorption efficiency in the C-band exceeds 99%. In addition, the thickness of the absorber is only 1.07 mm, which is 0.0154 times the wavelength corresponding to the minimum absorption frequency, and it has entered the sub-wavelength range. Other meta-unit cells all adopt square units, while this paper adopts a honeycomb regular hexagon sub-structure. Compared  
Figure 5:1 Absorption efficiency diagram for single component of MMA. to the square structure, the regular hexagon structure has a higher close-packing degree, and more absorbing units can be placed on the unit area. The proposed triple-band metasurface absorber has polarization-insensitive characteristics.