# Intelligent Target Design Based on Complex Target Simulation
## 3 Simulation Design  
First, we design the corner reflector, as shown in Figure 1. The corner reflector model considers the \(X\), \(Y\), and \(Z\) axes of the coordinate system as three right-angle sides. The positive direction of the \(X\) axis corresponds to the horizontal angle of \(0^{\circ}\), the positive direction of the \(Y\) axis corresponds to the vertical angle of \(90^{\circ}\), and the positive direction of the \(Z\) axis corresponds to the pitching angle of \(0^{\circ}\), where three metal plates are set as the ideal metal conductor surfaces with a side length of 0.5 m. A far-field plane wave with a frequency of 24 GHz is used for irradiating the corner reflector. The scanning angle range is \(-90^{\circ}\)\(-90^{\circ}\) in the azimuth dimension, the pitching angle is \(55^{\circ}\), and the angle scanning interval is \(1^{\circ}\). Figure 2 shows the simulation results. Figure 1: Triangular trihedral corner reflector. As Figure 2 shows, the maximum value of the RCS of the corner reflector is 25 dBsm, which is consistent with the theoretically calculated value given by (4). Figure 3 shows a change in the angle between the two sides to 60\({}^{\circ}\), and the corresponding simulation results are shown in Figure 4.  
Figure 4: Radar cross-section distribution characteristics with a pitching angle of 55\({}^{\circ}\). Figure 3: Corner reflector with a side angle of 60\({}^{\circ}\). Figure 2: Radar cross-section distribution characteristics of the corner reflector when the pitch angle is 55\({}^{\circ}\). Figure 4 shows that the 10 dB fluctuation range of the horizontal azimuth plane RCS value of the corner reflector is about 6\({}^{\circ}\) between 27\({}^{\circ}\) and 33\({}^{\circ}\). The 8 dB fluctuation range of the elevation azimuth plane RCS value is between 29\({}^{\circ}\) and 83\({}^{\circ}\). The 10 dB fluctuation range of the RCS value in the pitch and azimuth plane is about 61\({}^{\circ}\) between 24\({}^{\circ}\) and 85\({}^{\circ}\). This kind of fluctuation range can be used to simulate the RCS distribution characteristics in the sharp angular range, i.e., within a \(\pm\)15\({}^{\circ}\) range. Other parts are shielded with absorbent materials. Next, we design the Luneburg ball using FEKO. The Luneburg ball is irradiated by a far-field plane wave with a frequency of 24 GHz. The scanning angle ranges are 0\({}^{\circ}\) in the azimuth dimension and \(-\)90\({}^{\circ}\)\(\sim\)90\({}^{\circ}\) in the elevation dimension, and the angular scanning interval is 0.1\({}^{\circ}\), as shown in Figure 5.  
The Luneburg ball simulation structure consists of three dielectric layers and an outermost air layer. Equation (4) can be used to calculate the relative permittivity of the dielectric layer. Table 1 shows the specific design parameters. Figure 6 shows the simulation results obtained after setting the relevant parameters of the Luneburg ball according to Table 1. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Layers** & **Medium Reflectance** & **Relative Permititivity** \\ \hline
1 & 1.4 & 1.96 \\
2 & 1.34 & 1.7956 \\
3 & 1.22 & 1.4884 \\
4 & 1 & 1 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Design of the dielectric constant of each layer of a Luneburg ball. Figure 5: Simulation structure of a Luneburg ball reflector. Figure 6: Radar cross-section distribution characteristics of a Luneburg ball. As Figure 6 shows, the maximum RCS value of the Luneburg ball is about 0 dBsm, and the stable spatial angular range of the RCS is greater than or equal to \(110^{\circ}\). A change in the size of the Luneburg ball can vary the corresponding maximum RCS value if other simulation conditions and parameters are consistent. The width of the coverage angle in the secondary scattering direction can be changed by varying the size and position of the metal reflector. Therefore, the RCS distribution characteristics of the target stationary fluctuation range can be satisfied by changing the size of the Luneburg ball and appropriately designing the metal reflector wave material.