利用解析方法與數值分析方法重點研究了電磁波在圓形隧道、矩形隧道和拱形隧道中的傳播特性，得出了當隧道橫截面積越大衰減率越小，及隧道橫截面形狀對衰減率影響。當頻率較高時，圓形隧道、矩形隧道和拱形隧道的衰減率表達式是一致的；當隧道半徑或長邊長的一半大于波長10倍以上時，電磁波的衰減率很小，幾乎與橫截面形狀無關，僅僅與隧道橫截面積的大小有微弱的關系。

Using analytical method and numerical method, the paper emphatically researches propagation characteristics of electromagnetic waves in circular tunnel, rectangular tunnel and arched tunnel. A conclusion is made that the larger area of cross sections is, the lower attenuation rate is, and shape of cross sections affects on attenuation rate too. When frequency is comparatively high, circular tunnel, rectangular tunnel and arched tunnel have same formulation of attenuation rate. When the radius or half of larger side is ten times larger than the free-space wavelength, attenuation rate is very low and hardly related to the shape of cross sections, and only related slightly to the area of cross section of tunnel.