直线阵列的自然指向性，任意指向性，加窗后情况。直线阵列的时域及频域波束形成。圆弧镇的时域频域波束形成。(The natural directivity of the linear array, the arbitrary directivity, and the case after the window. The time domain and frequency domain beamforming of a linear array. The time domain frequency d