海上对流层大气波导顶部电磁盲区研究

Research of electromagnetic shadow zone in maritime tropospheric duct

用射线追踪法,分析了蒸发波导和表面波导顶部电磁盲区的分布特性.讨论了影响盲区面积大小的影响因素,仿真结果表明:波导顶部盲区位置随天线高度增加而远离发射天线的位置,随波导强度增大而接近发射天线位置;而顶部盲区面积主要随波导顶高变化.从陷获射线数目来看,表面波导对电波陷获能力要强于蒸发波导,且两者均在波导层底部陷获效果最佳.最后给出了顶部盲区面积的近似计算式.

Based on ray tracing method, the distribution characteristics of evaporation duct and sur- face duct top electromagnetic shadow zone are analyzed. The results show, that the position of duct top shadow zone will get far away from the position of transmitting antenna with the increase of antenna height, and that will get close to the transmitting antenna with the increase of duct intensity. The area of the top shadow zone mainly changes with the duct top height. Judging from the numbers of trapped rays, surface duct is stronger than evaporation duct in the ability of trapping electromagnetic wave, and both kinds of duct trapping abilities are best at the duct bottom. At last, an approximate calculation formula for the area of the duct top shadow zone is proposed.