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以无限长刚性柱体表面圆环阵为研究对象,提出了一种直接模态域稳健高增益波束形成方法,并将其应用到更实际的有限长刚性柱体表面圆环阵。该方法运用相位模态理论将波束响应表示成特征波束与模态系数的乘积后求和的形式,并结合散射理论求解了其模态域的噪声互谱矩阵。与已有的模态域稳健高增益方法需利用阵元域权值间接求取近似模态权系数不同的是,该方法利用二阶锥规划,在满足相关约束条件下直接给出了最优的模态权系数。仿真结果表明,直接模态域方法不仅能通过白噪声增益约束提高稳健性,在低频段还能通过改变模态阶数更灵活地在阵增益和稳健性之间折中,同时对旁瓣级等其它性能指标也能很好地控制,可用以有效设计实用的稳健高增益波束形成器。
In this paper, an infinite length rigid annular array is taken as the research object. A direct high-gain beamforming method with direct modal domain is proposed and applied to a more practical finite-length rigid circular cylindrical array. The method uses the phase mode theory to represent the beam response as the product of the eigenbeam and the modal coefficient, and then combines them with the scattering theory to solve the noise cross-spectrum matrix in the modal domain. Compared with the existing modal-domain robust high-gain method, which uses the weight of array element to indirectly calculate the approximate modal weighting coefficient, this method uses the second-order cone programming and directly gives the optimality under the condition of satisfying the relevant constraints Modal weight coefficient. The simulation results show that the direct mode domain method can not only improve the robustness by the white noise gain constraint but also flexibly reduce the matrix gain and robustness by changing the modal order in the low frequency band, Other performance metrics such as these are also well controlled and can be used to effectively design robust robust high-gain beamformers.