For radar systems, minimizing the radar cross section (RCS) of the antenna diminishes the likelihood of its detection by adversaries. In this paper, we investigate the movable time modulated array (MTMA) and propose an optimization method that effectively reduces the RCS while ensuring the beamwidth and sidelobe level (SLL). Genetic algorithms with a novel parameter updating strategies are used to solve the optimization problem. The on/off time of the RF switch of the MTMA as well as the position of the array element are used as optimization variables. Ultimately, simulation results validate the proposed approach. The findings of the numerical simulations indicate that the proposed method can be utilized to minimize the RCS of the MTMA while ensuring that the beamwidth and SLL performance are maintained.