滤波器幅度误差对频域宽带波束形成的影响

Influence of filter amplitude error on the frequency-domain broadband beamforming

阵列系统中,各个阵元的滤波器的幅度误差会对宽带波束形成造成影响。以频域宽带波束形成算法和滤波器幅度误差模型为基础,推导得到了存在滤波器幅度误差时频域宽带波束形成算法中自相关矩阵的表达式。通过对自相关矩阵的分析指出:滤波器幅度误差会引起自相关矩阵的秩增加,在做自适应干扰抑制时需要考虑更多的空间自由度。此外,误差的存在还会造成波束形成的性能下降。还给出了误差和性能损失之间的关系,为宽带相控阵系统中通道滤波器的设计提供了参考。

In an array system, the amplitude error of the filter in each element will affect the performance of the broadband beamforming. Based on the frequency-domain broadband beamforming algorithm and the filter amplitude error model, the influence of the filter amplitude error on the frequency-domain broadband beamforming is discussed. To analyze the error influence, the covariance matrix of the frequency-domain broadband beamforming in error case is calculated. Through the analysis of the covariance matrix in error case, it is shown that the rank of the covarianee matrix will increase and therefore more degrees of freedom are desired. Besides, the performance will become worsen due to the errors. The relationship of the error and the performance lose is also given, which may be beneficial for the design of the filter in broadband phased array.