一种方形腔体的目标散射特性及测量方法

Radar cross section (RCS) is an important index to evaluate the stealth performance of aircraft. As the inlet has a great contribution to the RCS of aircraft, it is significant to the study of the scattering of aircraft inlet. Compared with the common convex surface target, the inlet belongs to the cavity, so the far-field condition calculation and measurement system configuration should be adjusted according to its own unique scattering mechanism. Based on the theory of the relationship between rectangular waveguide and far field, the scattering law of cavity type targets such as inlet is analyzed. Taking a square cavity as an example, the quantitative echo analysis is carried out by using geometrical optics method, and the correctness of the theoretical derivation is verified by FEKO simulation. The RCS of the cavity target is measured in the compact field and the far field. The results of numerical calculation and experimental measurement show that when measuring the scattering of cavity like targets such as inlet, the test field only needs to ensure that the size of the inlet surface meets the far-field conditions, but the measurement system needs to have the measurement ability of 2 ~ 5 times the length of the inlet.