Explosion-proof safety analysis of far field radiation of 5G radio source in underground coal mine

Aiming at the promotion and application of 5G communication technology in coal mines, this paper analyzes the explosion prevention risk of radio frequency (RF) electromagnetic energy under the condition of far field radiation. In this paper, the equivalent model of the loop antenna and the theoretical calculation model of the spark power are established under the assumption that the characteristic impedance of the spark is matched with the internal impedance of the antenna. Secondly, for the 3.55 GHz operating frequency, a narrow bandwidth loop receiving antenna and a horn transmitting antenna by theoretical calculation are designed, and the S11 curve of the designed antenna by CST simulation software is verified. Finally, based on this, a simulation platform for transceiver antenna is built, which can be used to estimate the electric field strength and integrated voltage at both ends of the breakpoint of the loop antenna. The simulation results show that: when the electric discharge machining (EDM) is matched with the internal resistance and impedance of the antenna, the EDM power is maximum, and the impedance value of the EDM has no effect on the induced voltage of the whole antenna, and the power obtained by the EDM decreases with the increase of the distance between the transmitting and receiving antennas. The simulation and calculation show that when the transmitting antenna power is 100 W and the transmitting antenna gain is 5, the theoretical maximum spark power generated under the far-field radiation condition is not enough to ignite the gas. Therefore, the threshold power index in the standard may be too conservative and needs to be further verified.