# Shape Optimization of an Integrated Mast for RCS Reduction of a Stealth Naval Vessel
## 4 Conclusions  
We analyzed the RCS of an integrated mast and presented the optimized integrated mast shape for RCS reduction. We also checked the stealth performance of the optimized integrated mast shape though the computation of the RCS of a naval ship equipped with the integrated mast. The RCS of the integrated mast was investigated in terms of the threat frequency, the integrated mast shape and the direction and polarization of the incident waves. The optimization of the integrated mast was conducted for RCS reduction based on the shaping technique. The integrated mast was designed to have low RCS properties in the primary threat sectors except for the exceptional angle regions. The geometric mean and the arithmetic mean of the optimized mast were reduced by a maximum of 25.39 dBm and 46.46 dBm and by an average of 12.63 dBm and 14.57 dBm, respectively, compared with those of the initial mast. We also analyzed the RCS of a naval vessel equipped with the integrated mast and confirmed the improvement of the RCS. The geometric mean and the arithmetic mean of a naval ship equipped with the optimized mast were improved by a maximum of 24.05 dBm and 34.83 dBm and by an average of 10.42 dBm and 9.97 dBm, respectively, compared with the case of the initial mast. We confirmed that the optimized mast had relatively small RCS values in the threat regions except for the cardinal points \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Frequency**} & **Elevation** & \multicolumn{2}{c}{**Initial Shape**} & \multicolumn{2}{c}{**Optimized Shape**} & \multicolumn{2}{c}{**Without Mast**} \\  & **Angle** & **HH** & **VV** & **HH** & **VV** & **HH** & **VV** \\ \hline \multirow{6}{*}{L-band} & 0\({}^{\circ}\) & 11.10 & 8.75 & 11.00 & 8.04 & 9.99 & 7.26 \\  & 3\({}^{\circ}\) & 13.72 & 12.53 & 10.11 & 8.99 & 9.18 & 8.48 \\  & 5\({}^{\circ}\) & 17.10 & 17.63 & 10.27 & 8.91 & 9.06 & 7.77 \\  & 7\({}^{\circ}\) & 18.89 & 18.67 & 11.21 & 10.86 & 9.22 & 9.06 \\  & 10\({}^{\circ}\) & 31.70 & 31.86 & 13.24 & 12.78 & 10.64 & 11.07 \\  & 0\({}^{\circ}\) & 9.89 & 8.83 & 10.62 & 8.47 & 9.12 & 7.83 \\  & 3\({}^{\circ}\) & 10.62 & 11.33 & 8.67 & 8.58 & 8.12 & 8.05 \\  & 5\({}^{\circ}\) & 16.00 & 16.23 & 8.48 & 8.03 & 7.44 & 7.63 \\  & 7\({}^{\circ}\) & 20.45 & 20.52 & 8.70 & 8.69 & 7.42 & 7.56 \\  & 10\({}^{\circ}\) & 34.69 & 34.66 & 10.80 & 10.91 & 8.35 & 9.27 \\  & 0\({}^{\circ}\) & 9.66 & 8.69 & 9.89 & 8.44 & 9.32 & 8.20 \\  & 3\({}^{\circ}\) & 8.78 & 7.87 & 8.79 & 8.27 & 8.06 & 8.03 \\ X-band & 5\({}^{\circ}\) & 9.81 & 10.21 & 7.05 & 6.92 & 6.71 & 6.39 \\  & 7\({}^{\circ}\) & 20.26 & 20.36 & 7.28 & 8.10 & 6.43 & 7.07 \\  & 10\({}^{\circ}\) & 44.39 & 44.41 & 9.57 & 10.48 & 8.77 & 9.94 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Arithmetic mean of a naval vessel equipped with the integrated mast. (Unit: dBsm). \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Frequency**} & **Elevation** & \multicolumn{2}{c}{**Initial Shape**} & \multicolumn{2}{c}{**Optimized Shape**} & \multicolumn{2}{c}{**Without Mast**} \\  & **Angle** & **HH** & **VV** & **HH** & **VV** & **HH** & **VV** \\ \hline \multirow{6}{*}{L-band} & 0\({}^{\circ}\) & 3.95 & 2.89 & 0.96 & \(-1.07\) & \(-2.15\) & \(-6.13\) \\  & 3\({}^{\circ}\) & 11.98 & 11.08 & 2.54 & 1.86 & \(-1.98\) & \(-2.74\) \\  & 5\({}^{\circ}\) & 16.05 & 16.61 & 3.28 & 1.07 & \(-1.72\) & \(-2.60  
and minimally affected the RCS patterns of the naval vessel. These results can be used to develop an integrated mast for stealth vessels. The present work was conducted in cooperation with all authors. [PERSON] analyzed the problem and performed numerous simulations; [PERSON], D.Y., C.K., Y.S.Y., M.G.L., J.Y.P., K.C.H. and Y.B.P. contributed to the conceptualization, investigation and review; [PERSON] wrote a draft that was edited by all co-authors. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Not applicable.