## 4 Simulation Result
\begin{table}
\begin{tabular}{c c c c} \hline
**Category** & **Symbol** & **Value** & **Unit** \\ \hline Magnitude & \(A_{I}\) & 1 & V/m \\ Phase & \(\phi\) & 30 & \(\circ\) \\ Frequency & \(f\) & 2 & GHz \\ Frequency difference & \(\Delta f\) & 20 & Hz \\ Signal to noise ratio & \(SNR\) & 20 & dB \\ \hline \end{tabular}
\end{table} 
Table 2: Variables used in Equation (24). Figure 10: Canceling results using the MPM and proposed method with white Gaussian noise. Figure 9: Results canceled by the proposed method. In the previous paper mentioned before [8], the experiments were conducted using the vehicle model. In this experiment, the scaled-down model was used, and the canceling was carried out using a magnetic loop feeder inside the vehicle engine room. It took 155-188 ms for MPM analysis and cancellation, and 400-500 ms in total. The MPM operation relies on the performance of the computer's Central Processing Unit (CPU) because it takes the measured value from the power meter to the user's computer and processes it. In this paper, the vehicle engine room part was simulated similarly to the above situation. The size of the resonator and input path of IEMI is as below in Table 3.  
For effective internal field cancellation, the feeder should be installed where the surface current is most dense. The equipment is usually installed at the bottom of the protection facilities. Thus, the field is observed by installing sensors on the bottom of the cavity. A total of 70 probes were installed, i.e., 10 horizontally and 7 vertically, each 20 mm apart, 8 mm from the bottom. The figures below (Figures 12-14) show the shape of the cavity, the arrangement of the antennas, and the current distribution when the IEMI is incident from the front  
In the resonator of this size, the resonance frequency is about 1.25 GHz with the smallest value in the 101 mode. The resonance frequencies for several modes in the resonator are shown in Table 4.  
In this study, the target frequency was 1.414 GHz and canceled the resonance occurring at that frequency. The feeding structure for canceling the internal field was made using the loop type magnetic field feeder of the rectangular shape and installed based on the place where the current is most concentrated. Figure 15 shows the feeder shape and its S-parameters. \begin{table}
\begin{tabular}{c c c c} \hline \(m\) & \(n\) & \(p\) & **Frequency [GHz]** \\ \hline
1 & 0 & 1 & 1.249 \\
0 & 1 & 1 & 1.413 \\
1 & 1 & 1 & 1.599 \\
2 & 0 & 1 & 1.801 \\
2 & 1 & 1 & 2.060 \\
2 & 2 & 1 & 2.690 \\
1 & 0 & 2 & 2.134 \\
0 & 1 & 2 & 2.234 \\
2 & 0 & 2 & 2.498 \\ \hline \end{tabular}
\end{table} 
Table 4: Resonance frequency depending on the mode of this resonator. Figure 14: Current density distribution on the cavity. Figure 13: Addressed electric field probes and side view of the cavity. The field when the IEMI enters from the outside was measured by 70 probes installed earlier. Figure 16a shows the result of plotting the field on the bottom at a specific frequency by post-processing the result. In the same situation, the feeder generates an estimated canceling signal using a real-time reduction technique. The result of plotting this signal in the same position as before is also shown in Figure 16b. Figure 16: The result of post-processing the signal measured by the probe. (**a**) Electric field caused by external IEMI, (**b**) electric field generated by internal rectangular feeder, (**c**) field canceled by real-time reduction technique, and (**d**) field arranged in one dimension. Figure 15: Loop type feeder and its S-parameter. The field canceled by the generated signal estimated by the proposed technique is shown in Figure 16c. After arranging the addresses given to the electric field probes in a row, the results of the comparison in a one-dimensional graph were added to Figure 16d.