Abstract: Increasing element spacing appropriately and using subarray-based arrays are favorable to reduce the production cost of phased arrays, however, the rarefied array has unexpected grating lobes.To solve the proplems, an array is designed with no grating lobe.The subarrays are rotated in plane, and are distributed in the concentric ring structure around the center of the array.The range of the ring radii are analyzed for ensuring that each subarray will not overlap. Computational simulation is carried out to optimize the number of the subarrays in each ring and the radii of the ring using an improved method of exhaustion.The results show that, taking 4×4 subarrays and 1 024 elements as example, the method provides suppression of peak side-lobe level of -17.46dB.