###### Abstract
presented a metasurface pattern designed from the genetic algorithm; the 90% absorption bandwidth was confirmed in the 8.8-11.6 GHz range, for which the fractional bandwidth was 27.5% for both TE- and TM-polarization with incident angles from 0\({}^{\circ}\) to 60\({}^{\circ}\) [16]. [PERSON] et al. proposed an ultra-wideband metamaterial absorber that consisted of double layer metasurfaces optimally designed by the genetic algorithm and printed using carbon paste. Based on the simulation results it was shown that, the 90% absorption bandwidth was obtained from 6.3 to 30.1 GHz of which the fractional bandwidth was 130% for the normal incidence [17]. The absorber covered the 10.4-19.7 GHz range with effective absorption (above 90%) and it was printed on flexible substrate using graphene nano-flake conductive ink through a stencil printing method [18]. Even though the performance of EM absorbers using resistive ink and paste have been verified successfully, there is a limitation in applying to a realistic structure due to mechanical problems such as non-flexibility, weight of the structure, environmental resistance, etc. To surmount the limitations of single-layer and planar structures, multi-layer and three-dimensional absorbers were introduced [19; 20; 21; 22; 23; 24; 25]. A multi-layer and 3D structure-base with a switchable absorber was proposed because of diode bias voltage, but the structure could not avoid becoming a bigger size [19; 23]. [PERSON] et al. introduce a broadband absorber with a 3-layer stacked absorber with ITO films [20]. The measured bandwidth of the absorption was more than 85% from 6.0 to 16.7 GHz. [PERSON] et al. presented a reduced RCS patch antenna via dispersion engineering. The proposed structure resembled a pyramidal structure absorber [21]. [PERSON] et al. proposed an ultra-widebandfrequency-selective absorber designed by an adjustable and highly selective notch with multi-stacked layers. As a result, the absorption frequencies achieve about 4 to 18 GHz [22]. A double-sided parallel-strip line (DSPSL) was proposed by [PERSON] et al. employed to produce the required infinite impedance of the absorber [24]. The proposed absorber operated at 1.5-12.3 GHz. [PERSON] et al. designed a 3D honeycomb structure with glass/epoxy-MWCNT prepreg through an autoclave process. The absorption of the proposed honeycomb absorber was 3-16 GHz for more than 90% [25]. However, there are drawbacks in that the total size of the structure is bulky and/or the fabrication process becomes complex as the number of stacked layers is increased. To solve these problems, studies on EM absorbers in the form of composites to improve practicality have also been published [26; 27; 28; 29; 30]. In this paper, an ultra-wideband absorber is proposed with metasurfaces and a composite material for high practicality. The proposed absorber consists of double layer metasurfaces that are accomplished using commercial carbon paste with a screen-printing technology. The metasurfaces are composed of conductive pixelated patterns. The pixelated patterns were designed and optimized. To validate performance of the proposed absorber, the full-wave simulation based on the finite element method (FEM) was used. The bandwidth of 90% absorptivity was verified from 2.2 to 18 GHz, that is the fractional bandwidth is about 156% for both the transverse electric (TE) and magnetic (TM) polarizations (full-wave simulation only). The absorber was measured for incident angles of 0\({}^{\circ}\), 7\({}^{\circ}\), 15\({}^{\circ}\), 30\({}^{\circ}\), and 45\({}^{\circ}\) with TE polarization and it was found that the simulated and measured results agreed very well with each other. Also, the proposed absorber has good environmental resistance in the form of composite material and strong mechanical performance for various applications.