## 4 Conclusions  
In this paper, the authors presented a thin-profile, resistive, film-based MTM-EM absorber exhibiting an operating frequency bandwidth of 20.8 GHz (123.1%), from 6.5 GHz to 27.3 GHz, with a 90% absorbance criterion. This includes parts of the C-band, X-band, Ku-band, and K-band. The highest absorbance of 99% occurs at 18.65 GHz. The proposed absorber was insensitive to the polarization and incidence angles in TE and TM mode at all operating frequencies, due to its highly symmetrical configuration. The working mechanism of the proposed work was analyzed and explained in detail by the surface current distribution and the surface power loss simulations. A prototype was built, and all the computed expectations were verified experimentally. The proposed MTM-EM absorber showed a wide-operating frequency range with a relatively thinner profile than in other works that use ITO films. It was also physically transparent since PET was used as a base film for the ITO coating. Once the supporter is flexible, it is believed that it could be effectively applied in curved glasses, such as a canopy or the flexible displays of mobile phones, as a means of reducing the RCS or absorbing unwanted EM energies.  
Conceptualization, S.P. and I.-J.Y; methodology, S.P., G.S., H.K., Y.K. and I.-J.Y.; software, S.P., G.S. and I.-J.Y.; validation, S.P., G.S. and I.-J.Y.; formal analysis, S.P., G.S. and I.-J.Y.; investigation, S.P., G.S., H.K., Y.K. and I.-J.Y.; resources, S.P., G.S., H.K., Y.K. and I.-J.Y.; data curation, S.P., G.S. and I.-J.Y.; writing--original draft preparation, S.P.; writing--review and editing, I.-J.Y.; visualization, S.P.; supervision, I.-J.Y. All authors have read and agreed to the published version of the manuscript.  
This research has been supported by the Defense Challengeable Future Technology Program of Agency for Defense Development, Republic of Korea.  
Not applicable.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Reference**} & **Center** & **Fractional** & **Thickness** & **Figure-of-Merit** \\  & **Frequency** & **Bandwidth** & **[mm]** & **Merit** \\  & **[GHz]** & **[GHz]** & **[mm]** & \\ \hline \multirow{2}{*}{[24] *} & \multirow{2}{*}{10.33} & 8.10 & 5.35 & \multirow{2}{*}{425.6} \\  & & (78.4\%) & (0.184\(\lambda\)) & \\ \hline \multirow{2}{*}{[25] *} & \multirow{2}{*}{2.64} & 2.06 & 17.10 & \multirow{2}{*}{518.5} \\  & & (78.0\%) & (0.150\(\lambda\)) & \\ \hline \multirow{2}{*}{[26]} & \multirow{2}{*}{11.50} & 15.40 & 8.6 & \multirow{2}{*}{406.2} \\  & & (133.9\%) & (0.330\(\lambda\)) & \\ \hline \multirow{2}{*}{[27] *} & \multirow{2}{*}{9.45} & 11.18 & 6.40 & \multirow{2}{*}{586.8} \\  & & (118.3\%) & (0.202\(\lambda\)) & \\ \hline \multirow{2}{*}{[28]} & \multirow{2}{*}{18.40} & 20.60 & 3.30 & \multirow{2}{*}{553.1} \\  & & (112.0\%) & (0.202\(\lambda\)) & \\ \hline \multirow{2}{*}{This work *} & \multirow{2}{*}{16.90} & 20.80 & 3.35 & \multirow{2}{*}{624.2} \\  & & (123.1\%) & (0.197\(\lambda\)) & \\ \hline \hline \end{tabular}
\end{table}
Table 1: Comparison table of the ITO film-based absorber. The values from the measurement are marked with an asterisk. The values without the asterisk are from the simulation. All works in this table are transparent. The figure-of-merit is calculated as the ratio of the fractional bandwidth to the electrical thickness.  
**Acknowledgments:** The authors thank [PERSON] and [PERSON] from Chung-Ang University, Seoul, Republic of Korea, for the technical support in measurement in this work.  
**Conflicts of Interest:** The authors declare no conflict of interest.