S-shaped two-dimensional(2-D) convergent nozzle with different width-height ratios were designed by the self-adaptive super-ellipse method when the inlet and outlet area

the eccentricity

area variation and the centerline variation of nozzles were kept constant.Combining iterative physical optic method with equivalent edge currents method

a code capable of calulating the edge diffraction and total scattering field was developed to simulate the radar scattering characteristics of cavities.The accuracy and reliability of the code was verified by comparing the experimental data from references with calculated data.Under horizontal and vertical polarization ways

radar cross-section(RCS) characteristics of S-shaped 2-D convergent nozzles were analyzed.The results show that the width-height ratio has little effect on the edge diffraction field of S-shaped 2-D convergent nozzle under horizontal and vertical polarization ways

and the difference of the outlet width-height ratio of the S-shaped 2-D convergent nozzles' RCS is less than 4dB.The nozzles' outlet width-height ratio has a large influence on total scattering field.At the positive detection angle within the large range of the detection angle the total scattering filed has lower RCS while the width- height ratio is 1.5

and at the negative detection angle

it has lower RCS while the ratio is 3.5.