基于载体对消方法的缝隙小角域散射特性研究

An important part of the scattering of stealth aircraft is slit scattering. Though researches have done on it, none of them has produced results in small angular domain (from -30° to 30°). This paper applied the carrier scattering method based on superposition principle to electromagnetic scattering computation for more accurately studying the electromagnetic scattering characteristics of slit. The effectiveness and accuracy of carrier cancellation method are verified by one-dimensional imaging of a plate with slit. Statistics of polarization characteristics and variation pattern of slit scattering in small angular domain with the width and length were made at 10 GHz frequency. The study results with different slit width show that, in small angular domain, horizontal scattering is larger than vertical polarization scattering when the slit width is less than a quarter of wavelength; otherwise, horizontal scattering is smaller than vertical polarization scattering. It is also found that the radar cross section (RCS) value of the slit increases faster with the growth of slit width under vertical polarization. The results with different slit length demonstrate that, in small angular domain, the mean value of electromagnetic scattering increases with the growth of slit length (200-1 000 mm) and the approximate range of scattering mean ranges from -22.2 dBsm to -8.4 dBsm in horizontal polarization and from -27.3 dBsm to -13.3 dBsm in vertical polarization. The relationship between RCS mean and slit length can be fitted to obtain RCS with a certain length, and thus the approximate range of RCS with different slit length could be calculated.