Aperture synthesis with high spatial resolution would seriously increase the hardware requirements and system complexity. To reduce the system complexity, Rotating mirrored aperture synthesis (RMAS) that combines the antenna array rotation with mirrored aperture synthesis was proposed to reduce the number of antennas. In this paper, the sieving method is presented to optimize the array configuration for RMAS. The initial simulation results demonstrate the validity of the proposed method and the optimized array of RMAS can reconstruct the brightness temperature of the observed scene with fewer antennas.