中文摘要：

在研究矩形巷道电磁波传播特性时,如果单一采用自由空间传播模型或波导传播模型,将导致仿真结果不够精确.为了使模型传播特性更接近于实际传播特性,可根据两种模型场强建立混合模型.通过理论推导确定混合模型分界点,进而研究分界点处电磁波模式数量对混合模型精确度的影响,然后研究在混合模型有较高精确度的条件下,频率和截面尺寸对分界点处需考虑的模式数量的影响.通过仿真研究,结果表明,混合模型分界点处考虑一定模式数量的电磁波时,精确度会有很大提高.同时,在确定较高精确度的条件下,分界点距发射点的距离会随着巷道截面积和传播频率的增大而增加,分界点处所需考虑的波导模式电磁波数量也会随之增加.

英文摘要：

The use of a free space propagation model or a waveguide propagation model to study the character- istics of the electromagnetic wave propagation in rectangular tunnels will lead to a inaccurate simulation. In or- der to make the propagation characteristics close to the actual propagation characteristics, a hybrid model will be established based on the field strength of the two models. Firstly, the dividing point of the hybrid model will be determined. Then, the effect of electromagnetic wave modes numbers on the accuracy of the hybrid model will be discussed. Finally, the wave mode numbers for different propagation frequencies and tunnel cross-sec- tional sizes will be calculated. According to the simulations, the results show that the accuracy will be greatly improved when the considered modes of the hybrid model reach to a certain number at the dividing point,and the considered mode numbers and the distance between the dividing point and launching point will increase with the tunnel cross-sectional size and the propagation frequency.