# Analysis of High-Power Radar Propagation Environments Around the Test Site
## 3 Analysis of the Propagation Environment During Radar Operation
Based on the simulation, the received power is calculated as \(-\)26.48 dBm (1.52 V/m) and \(-\)28.32 dBm (2.77 V/m) in the X-band and Ku-band, respectively. Although the electric field does not exceed the reference level in either the X-band or Ku-band, the electric field strength around the Rx. system increases compared to the scenario shown in Figure 4. These results show that the proposed method can be used to analyze the potential impact on received EM waves in areas near the radar site in advance, allowing for \begin{table}
\begin{tabular}{c c c} \hline
**Parameters** & **X-Band (8 GHz)** & **Ku-Band (18 GHz)** \\ \hline Realized gain (dBi) & 30.07 & 35.86 \\
3 dB beam width (\({}^{\circ}\)) & 4.9 & 2.2 \\ Side lobe level (dB) & 13.3 & 13.5 \\ \hline \end{tabular}
\end{table} 
Table 1: Characteristics of the radar system radiation patterns. \begin{table}
\begin{tabular}{c c c c} \hline  & & **X-Band** & **Ku-Band** \\ \hline Minimum received & Tx. area & \(-\)216.75 & \(-\)218.17 \\ power (dBm) & Rx. area & \(-\)218.87 & \(-\)219.95 \\ Maximum received & Tx. area & \(-\)44.39 & \(-\)59.09 \\ power (dBm) & Rx. area & \(-\)52.86 & \(-\)59.94 \\ \hline \end{tabular}
\end{table} 
Table 2: Received power at the analyzed frequency. Figure 4: Propagation path and received power in the surrounding area during radar performance measurement: (**a**) propagation path from the Tx. system to the Rx. system; (**b**) distribution map of received power at 8 GHz; (**c**) distribution map of received power at 18 GHz. Figure 5: Simulation of the received electromagnetic power within the area near the Tx. system during beam steering errors: (**a**) received power at 8 GHz with an input power of 1 W; (**b**) received power at 18 GHz with an input power of 1 W.  
Even though the electric field strength may already be low, the field strength around the radar site can be further minimized in cases where the radar is misaligned. One of the possible solutions is to consider the placement of absorber structures. Figure 6 shows the analysis results of the received power distribution in the nearby area when absorber (\(\epsilon_{r}=22.9\)\(-\)\(j1.37\), \(\tau=-29.90\) dB) structures are placed in front of the Tx. radar. In this analysis, the transmitted power and elevation angle of the Tx. radar systems are set the same as in Figure 5, and absorber structures are placed in front of the radar to analyze the attenuating rate of the received power reaching the nearby area. The height of the absorber is applied from 1 m to 2 m in 0.5 m increments. According to the simulation result with 1 m of absorber height, the received power is calculated as \(-30.82\) dBm in the X-band and \(-32.67\) dBm in the Ku-band at a transmitted power of 1 W, as shown in Table 3. The maximum electric field near the Tx. Radar system is 0.92 V/m for the X-band and 1.68 V/m for Ku-band. A comparison of the received electric field depending on absorber installation shows an attenuation rate of 39.47% and 39.35% in each frequency band. Furthermore, the attenuation rate of the received electric field increases with the height of the absorber structures. In addition, we move the 1 m-high absorber 5 m closer to the radar to assess the impact of its position. In this configuration, the maximum received power is \(-22.23\) dBm, representing an increase of 8.59 dB compared with the original setup. Therefore, installing absorber structures near the Tx. system can further reduce the electric field around the testing areas while the radar system is in operation. Figure 6: Simulation of received power near the Tx. system with an absorber under a beam steering error scenario: (**a**) scenario of beam steering error with the absorber; (**b**) received power at 8 GHz with a 1 m high absorber; (**c**) received power at 18 GHz with a 1 m high absorber.