Safety power analysis of metal oscillator structure in mine 5G radiation field

Abstract

There are flammable and explosive gases such as gas underground in coal mines. The electromagnetic waves radiated by the 5G wireless communication system base station antenna are absorbed by the underground metal structure, generating discharge sparks at the metal structure breakpoint. When the energy of the electric spark reaches the minimum ignition energy of gas, an explosion may occur, which limits the application of 5G technology in coal mines. In order to evaluate the safety of the RF power of 5G wireless communication base stations, the relationship between RF power, maximum radiation field strength, and distance is obtained by analyzing the coupling of electromagnetic waves with metal structures. Using the minimum ignition energy as the safety criterion, it can be concluded that when the receiving power of the antenna load is less than 2.625 W, it can ensure that it will not cause gas explosions. The analysis shows that 700 MHz should be given priority as the 5G working frequency band in coal mines underground. By analyzing the directional coefficient, it is concluded that a symmetrical oscillator antenna metal structure with an arm length to wavelength ratio of 0.65 should be chosen for research. The safe electric field strength of the symmetrical oscillator antenna metal structure is 202.9 V/m, and the minimum safe distance is 0.2 m. The simulation results show that the electric field distribution is extremely uneven in areas less than 0.2 m away from the transmitting antenna. The electric field distribution is relatively even in areas more than 0.2 m away from the transmitting antenna. The minimum radio frequency power that causes a gas explosion in an area greater than 0.2 m from the transmitting antenna is 27.45 W.

Keywords

• mine 5g
• safe power
• symmetric oscillator
• rf equipment
• minimum ignition energy
• safe electric field strength
• minimum safe distance