为了降低宽带阵列恒定束宽的实现复杂性,在分析宽带阵列稀疏性的基础上,构造了以阵元和抽头延迟线(TDL,tapped delay line)稀疏性的凸组合为目标函数,满足恒定束宽约束的波束形成器优化模型,降低了所需的阵元和TDL个数。引入重加权机制,通过序列凸优化,使稀疏性递增并收敛到最大值,证明了保证波束形成器稳健性的范数约束与最大TDL稀疏目标函数之间的等价性。仿真结果表明,可用较少的阵元及TDL个数获得相同的恒定束宽性能,具有工程实用价值。
To reduce the complexity of broadband array systems, an optimization model was built based on the analysis of the sparsity of the broadband array. The objective function was the convex combination of sensor and TDL sparsity with the constraint of constant beamwidth. By re-weighting the objective function, the sparsity of the array weights increased and converged to the maximal value. The equivalence between the norm constraint on array weights and the sparsity of TDL was proved. Simulation results demonstrate that to obtain the same performance, the number of sensors and TDL of the proposed beamformer needed is decreased which reduces the system complexity, showing that the beamformer designed has great practical value.