基于一致性几何绕射理论分析飞机机体结构对安装在机背上的双脊喇叭天线辐射特性的影响，分析了机载双脊喇叭天线各辐射场分量的计算方法，计算了天线经简化机体散射后的方向图。仿真实验结果表明，机体对天线辐射特性的影响主要在机身表面的反射、结构边缘的绕射，而表面爬行波对天线方向图主瓣的影响非常小，其影响主要在后瓣。计算结果可为天线安装后辐射性能预测和最优化配置提供理论依据。In this paper, the Uniform geometrical Theory of Diffraction(UTD)is first time employed in conjunction with approximate models of the aircraft structure to analyze the effect of aircraft for double-ridged horn pattern on the top fuselage and to analyze the scattering field formulas effected by aircraft structure. The scattering fields are computed while the radiation pattern of double-ridged horn antenna mounted on the top of an aircraft is obtained. The simulation results show that the effect of the aircraft on radiation pattern is the surface reflecting field, the edge scattering field, and the surface creep wave which contributes to the backload of the pattern. The results of this paper can be used to analyze the radiation pattern of airborne antenna and to optimize the airborne antenna disposition.