Side lobe levels reduction in digitally optimized time modulated linear arrays using particle swarm optimization technique

This paper presents a new technique to reduce side lobe levels (SLLs) and side band levels (SBLs) in time modulated antenna arrays (TMAAs) by optimizing discrete values of static excitation amplitudes and continuous values of on-time duration of the antenna elements. The particle swarm optimization (PSO) technique has been utilized to suppress SLL and maximum of SBL (SBL_max) to a pre-defined desired value while the discrete values of excitation amplitude are obtained such that five bit digital attenuators can be used to control them. The simulation result of a 30 element time-modulated linear antenna array (TMLAA) is presented by reducing SLL and SBL_max to below -40 dB and to -30 dB respectively.