# Study on Electromagnetic Radiation Interference Caused by Rocket Fuel
## 4 Experimental Results  
To simulate the combustion of rocket fuel, we conducted six sets of electromagnetic radiation measurement experiments. The type of fuel in each set of experiments was different, but all are commonly used for aviation launch missions. The details of the fuels used by the different experimental groups are shown in Table 2. In order to obtain the experimental results, we used the measurement system in Figure 2 to measure the electromagnetic radiation generated by the deflagration of high-energy materials, and used the experimental methods in Section 2 to process and analyse the electromagnetic signals. The electromagnetic radiation generated by rocket fuel could be characterized by two indicators: one was the complexity indicator of energetic material electromagnetic radiation, and the other was the threat level of electromagnetic interference on electronic equipment. Equations (1)-(3) in Section 2 can completely express the characteristics of electromagnetic radiation generated by energetic materials. In this article, an evaluation method for an electromagnetic environment was established. This method processed the three characteristic values of SO, TO, and FO, which represent the average power density spectrum, the time occupancy, and the spectrum occupancy, respectively, and obtained the complexity evaluation of the electromagnetic radiation. The complexity indicator of electromagnetic radiation was helpful in terms of accurately evaluating the electromagnetic radiation generated by rocket fuel, which is shown in the first and second columns of Table 3. On the other hand, we conducted a detailed theoretical analysis of the energetic material's electromagnetic radiation interference on electronic equipment in Section 2 and established a complete mathematical model, which is described by Equations (6), (9), and (12). According to Equations (6), (9), and (12), the parameters ST, TT, and FT represent the spatial threat degree, the time-domain threat degree, and the frequency-domain threat of the electronic device, respectively. We processed these three parameters mathematically to obtain the threat level of electromagnetic radiation to electronic equipment, which is shown in the third and fourth columns of Table 3. The index was helpful in terms of accurately evaluating the threat of electromagnetic radiation generated by rocket fuel on electronic devices. The experimental results of rocket fuel electromagnetic radiation measurement are shown in Figures 5 and 6, which show the time-domain and frequency-domain electromagnetic signal produced by the deflagration of six sets of high energetic materials. In Figures 5 and 6, the subgraphs from a to f represent experimental cases from 1 to 6, respectively. The electromagnetic radiation signals produced by the deflagration of different kinds of energetic materials were completely different under the condition of constant weight. The electromagnetic radiation produced by Lox-Hydrogen was the earliest, but the duration of 0.04 s was the shortest. The electromagnetic radiation produced by Lox-Propane had the longest duration of 0.6 s, but the start time was the latest. The time domain features of the electromagnetic radiation generated by H2O4-Hydrazine and AP-HTPB-Al were almost the same. The frequency range of the electromagnetic radiation generated by energetic materials was from 60 MHz to 1550 MH. Lox-propane produced the widest electromagnetic spectrum, reaching 450 MHz, while Lox-Hydrogen produced the narrowest electromagnetic spectrum of 35 MHz. Lox-Propane and Lox-Kerosene could produce high frequency electromagnetic interference exceeding 1000 MHz. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Cases** & **Combination** & **Mixture Ratio** & **Mass/kg** \\ \hline
1 & Lox-Hydrogen & 6 & 1000 \\
2 & H2O4-Hydrazine & 1.08 & 1000 \\
3 & AP-HTPB-Al & 5.17 & 1000 \\
4 & Lox-Methane & 2.77 & 1000 \\
5 & Lox-Propane & 1.7 & 1000 \\
6 & Lox-Kerosene & 2.33 & 1000 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Experimental cases.