不同出口形状S形喷管的RSC特性

采用超椭圆方法、面积变化规律及中心线变化规律设计了三种出口形状的S形喷管，结合等效边缘电磁流（EEC）法和迭代物理光学（IPO）法开发了计算程序；EEC法分析喷管出口边缘产生的绕射场对S形喷管的雷达散射截面（RCS）的贡献；IPO法分析S形喷管腔体产生的散射场对S形喷管RCS的贡献；通过对两种电磁场所产生的电磁波的矢量叠加计算S形喷管的总RCS；在此基础上，研究了3种不同出口形状的S形喷管的RCS特性.结果表明：出口形状对RCS影响较大；圆形出口是3种S形喷管中RCS最小的；相互错位的锯齿修型可有效减小喷管的RCS；喷管的S形结构设计使得全局探测角内总散射场的RCS不关于0°探测角对称，并使得最大RCS移向正探测角.

RCS characteristic of S-shaped nozzle with different outlet shapes

Based on the expressions of the super-elliptic method, the center-line and proportion variation patterns, three types of S-shaped nozzle with different outlet shape were designed. A program was developed to combine the equivalent edge currents(EEC) method and iterative physical optic (IPO) method. The EEC method was applied to calculate the contribution of edge diffraction field of nozzle outlet to the radar cross section (RCS) of S-shaped nozzle, and the IPO method was used to calculate RCS created by scattering field of cavities of S-shaped nozzle. The total RCS of S-shaped nozzle was calculated through vector summation of electromagnetic wave generated by two electromagnetic fields. On this basis, RCS characteristics of the S-shaped nozzle with three different outlet shapes were investigated. The results show that the outlet shape has great effects on RCS, and the S-shaped nozzle with circular outlet have the minimum RCS. The dislocation of sawtooth modification can effectively decrease the RCS of nozzle. The S-shaped structure of nozzle makes the RCS of the total scattering filed not symmetrically distribute about 0° detection angle within the range of global detection, which shifts the maximum RCS to the region of the positive detection angle.