Side-lobe constrained beamforming undervirtual expansion of L-shaped array

To reduce the side-lobe level of L-shaped expansion array and improve the output signal to interference and noiseratio (SINR), the algorithm of side-lobe constraint based on minimum variance distortionless response ( MVDR-SC) is proposed. Firstly, the approach of mixing diagonal loading and Mailloux-Zatman (DLMZ) is used to taperthe covariance matrix of the expansion array. Then, the second order cone programming ( SOCP) obtained byconstructing a new matrix is used to control the beam side-lobe. Finally, the new adaptive weight numbers areconstructed by adjusting the proportion between DLMZ and SOCP. Simulation results show that the MVDR-SCalgorithm can effectively reduce the side-lobe of beamforming under the L-shaped expansion array and obtain alarger output SINR. At the same time, it has good robustness to the mutual coupling error.