# Analysis of High-Power Radar Propagation Environments Around the Test Site
## 4 Verification of Analysis Results Through Comparison of Measurement and Simulation  
To verify the reliability of the results analyzed through the simulation model, measurements are conducted at the actual radar site and compared with the simulation results. This measurement is conducted in the L-band (1.2 GHz) to minimize electromagnetic interference at the operational radar site. The Tx. signal is radiated with a 0 dBm L-band frequency by the signal generator. The Rx. system employs the same monopole antenna as that of the Tx. system and is connected to a spectrum analyzer (Anritsu MS2720T (Anritsu Corporation, Atsugi, Japan)) located approximately 120 m from the Radar Control Center, as shown in Figure 7a. In this simulation setup, the Tx. antenna uses the same monopole antenna as that of the measurement system and is placed in front of the Radar Control Center, with a transmitted power set to 0 dBm. Figure 7b illustrates the measurement setup used to determine the insertion loss of the RF cable for measurement verification. In this setup, a Rohde & Schwarz SMBV100A Vector Signal Generator (Rohde & Schwarz GmbH & Co. KG, Munich, Germany) is configured to output a signal at a frequency of 1.2 GHz with an output power of 0 dBm. This signal is transmitted through the testing RF cable and received by an Anritsu MS2720T Spectrum Analyzer (Anritsu Corporation, Atsugi, Japan), which measures the power level of the received signal. The insertion loss is obtained by subtracting the measured power from the transmitted power (0 dBm). As shown in Figure 7b, the received signal strength at the center frequency of 1.2 GHz is observed to be \(-5.01\) dBm, resulting in a total insertion loss of 5.01 dB. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Height of** & & & & \\
**Absorber** & & & & \\ \hline
1 m & 8 GHz & 1.52 V/m & 0.92 V/m & 39.47\% \\
1.5 m & 18 GHz & 2.77 V/m & 1.68 V/m & 39.35\% \\
1.5 m & 8 GHz & 1.52 V/m & 0.29 V/m & 80.92\% \\
18 GHz & 2.77 V/m & 0.46 V/m & 83.39\% \\
2 m & 8 GHz & 1.52 V/m & 0.17 V/m & 88.82\% \\
18 GHz & 2.77 V/m & 0.18 V/m & 93.5\% \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Maximum received electric field in the analyzed area based on the height of the absorber. Figure 7: Measurement system setup: (**a**) measurement environment; (**b**) cable loss measurement. Figure 8 presents the fabrication and reflection coefficient of the \(\lambda\)/4 monopole antenna used for measurement. Figure 8a provides a fabricated antenna with a radiator placed at the center of a ground plane (30 cm \(\times\) 30 cm). The radiator of the monopole antenna is designed to operate in the L-band with a length of approximately 6.25 cm. Figure 8b shows the reflection coefficient of the fabricated antenna. The measurement and simulation results are indicated by solid and dashed lines, respectively. The measured reflection coefficient is \(-\)25.1 dB, while the simulated result is \(-\)24.07 dB at the operating frequency of 1.2 GHz. It is observed that there is a discrepancy between the measured and simulated results, and it can be attributed to parasitic conductance or inductance caused by the discontinuity between the radiator and connector. Figure 9 represents the radiation patterns of the Tx. and Rx. antenna. The \(\lambda\)/4 monopole antenna is measured in the full anechoic chamber, as shown in Figure 9a. The fabricated antenna is fixed with a Styrofoam jig, and the antenna gains of the fabricated antenna are measured to verify antenna feasibility. Figure 9b,c illustrate the measured and simulated 2D radiation patterns of the monopole antenna (the azimuth and elevation directions). The measured radiation patterns show an omnidirectional pattern with an average gain of 0 dBi, and they also have a good agreement with the simulated result (dashed line). Figure 10 represents the measurement setup at the actual radar site for verifying the integrated simulation model.