Mode Number Of Electromagnetic Waves Of Hybrid Model In Rectangular Tunnels

Application of Wireless Communication Systems is an important aspect of modern coal production in underground coal mine, and it has important significance in enhancing the level of management, improving productivity, strengthening safety and protecting security of life and property. However, the tunnel is a kind of special limited space, and the electromagnetic waves propagation characteristics in tunnels are very different to those on the ground. There are many influence factors on the electromagnetic waves propagation of tunnels, such as the cross section areas of tunnels, the propagation frequency, and the gradient and roughness of the tunnel walls. In order to establish the safe and reasonable underground communication system, we need further research the electromagnetic waves transmission characteristics, so that we can achieve the flexible, reliable, and efficient system.Firstly, this paper introduces the cut-off frequency, the boundary conditions and the basic theory of electromagnetic wave propagation in rectangular tunnels. Then analysis of the propagation characteristics of horizontal polarization and vertical polarization mode, in that way, we can find the similarities and differences between different model number and fundamental model in electromagnetic wave attenuation and attenuation trend. Based on the simulation method, research the electromagnetic wave transmission characteristics on low-order modes and high-order modes.Secondly, this paper does the research on hybrid model characters. In the near field, electromagnetic waves have less reflection and refraction, and the field strength fluctuation of electromagnetic waves is severe, which result in the complex characteristics of propagation. In the far field region, electromagnetic waves have more reflection and refraction; the high-order mode waves attenuate rapidly and have less impact on propagation characteristics. According to the different region characters, we can establish the hybrid model and determine the dividing point, study the impact of frequency and cross-sectional size on mode number.Finally, based on the hybrid model, we consider that the hybrid model should not only consider the base mode of electromagnetic wave function, but also should more consider the low order mode of electromagnetic wave function. Through the simulation, we should learn the effects of mode number on the transmission characters of the hybrid model, so that to improve the model accuracy. As the model has higher accuracy, more model number need to be consideredThe innovation of this paper is mainly at the contrast method to approximate the wave characters of the actual electromagnetic roadways with different number of electromagnetic wave, the frequency and the roadway section have effects on electromagnetic waves. A hybrid model is established from the field characters, combined with the research on the quantitative model of waveguide mode, analyze the effect of frequency and the tunnel section on the number of dividing points and hybrid model.