Research on the safety of 5G electromagnetic wave radiation energy in coal mine

The electromagnetic wave energy emitted by wireless radio frequency equipment in coal mines is coupled into the energy storage elements on the metal structure. And once the metal structure has a breakpoint and an on-off contact occurs, the discharge spark generated by the accumulated electromagnetic wave energy may cause a gas explosion. 5G uses large-scale multiple-input multiple-output (MIMO) technology, which has the problem of power superposition between multiple transmitting antennas, increasing the possibility of igniting the gas. In order to solve the above problem, the coupling process of electromagnetic wave radiation energy and metal structure is analyzed, and the conditions for the discharge spark to ignite the gas when the metal load is in resonance are obtained. It is found that if the energy released by the discharge spark exceeds 0.28 mJ in 100 μs, the gas can be ignited. The ray tracing method is used to establish a roadway electromagnetic wave energy propagation model. The electromagnetic simulation software Wireless insite is applied to simulate single-antenna and multi-antenna radio frequency equipment in the 5G frequency band. The results show that electromagnetic wave energy propagates in the form of radiation. The electromagnetic wave energy emitted by single-antenna radio frequency equipment with operating frequencies above 700 MHz is intrinsically safe, and the minimum safe distance between 4T4R (4 transmitting and 4 receiving) multi-antenna radio frequency equipment and metal structures is 0.25 m.