In this paper, a novel technique for electronic beam steering in Time Modulated Linear Array (TMLA) is proposed. The beam steering technique is realized at the first sideband by controlling the switch-on time sequences of each element in the TMLA without using phase shifters. The Differential Evolution (DE) algorithm is employed to improve the gain and suppress the Side Lobe Levels (SLLs) at both the center frequency and the first sideband, simultaneously. An S-band 8-element double-layered printed dipole linear array was used to verify the technique experimentally.