基于近场时域谱的紧缩场口径优化设计

根据口径近场的时域谱,可以在全频段评估口径的绕射特征,从而建立紧缩场口径设计的一般准则.在X波段8～12GHz,计算了几种限度为5m×5m口径的近场时域谱.计算结果表明,在紧缩场设计中,为降低边缘绕射场电平,方口径优于圆口径,理想多项式锥削优于余弦锥削和均匀分布.提出两种工程化的边齿设计方法,在口径场均匀分布条件下,近场时域干扰谱分量均低于-25dB.口径近场计算均采用口径场卷积法.

Optimization design of CR aperture based on time domain spectrum

According time domain spectrum of the aperture near field, the diffractive characteristics of an aperture can be estimated at a whole band. Therefore, general rules of compact range (CR) aperture design can be established. At X band, from 8GHz to 12GHz, the near field time domain spectrum of several kinds of aperture are computed and compared. The results show that in order to reduce the diffraction of the edge, the perfectly polynomial taper is prior to cosine taper and uniform distribution. Two basic kinds of serration edge in practical engineering are presented and estimated. With a uniform field distribution, the edge diffraction field levels of both are lower than -25 dB. All the numerical results in this paper are based on aperture field convolution method.