Beampattern synthesis for concentric circular ring array using MMSE design

In a recent paper by Li et al. (2003), we proposed a method to achieve desired sidelobe level for broadband 3D beamforming using a discrete concentric circular ring array. To achieve an ideal sidelobe level using the previously proposed method, a sufficiently large number of array elements are required. If there are not enough array elements, sidelobe level is increased and uncontrollable. This paper proposes a pattern synthesis method based on the minimum mean-squared error (MMSE) criteria to achieve a better design when only insufficient array elements are available. The proposed method finds the optimal beamforming solution by minimizing the mismatched error between the synthesized and desired beampattern, which includes the error introduced by insufficient number of array elements. Experiments confirm the improvement on sidelobe control using the proposed design method.