Abstract: To suppress the concentrated jammers in the presence of unknown mismatches of the adaptive arrays, a robust beampattern synthesis algorithm with low response in a specified region is proposed. The proposed algorithm minimizes the worst-case output power while maintaining the response of the robust region distortionless and low response in a specified region, where the concentrated jammers may impinge according to some prior information. The proposed algorithm has the form of a semi-definite programming and hence can be efficiently solved by convex optimization toolbox. The numerical examples demonstrate that the proposed algorithm has a better robustness, higher output signal-to-interference-plus-noise ratio and more accurate power estimation as compared with the known beampattern synthesis algorithms.