Synthesis of simultaneous sum and difference patterns in uniformly excited time-modulated linear arrays using firefly algorithm

Abstract

In this paper, sideband radiations which are generally regarded as the undesired effects of time-modulated antenna arrays (TMAAs), are exploited to design multi-beam antenna arrays. Time modulation (TM) is applied into uniformly excited linear array of half wave dipole radiators to generate low side-lobe sum and difference patterns at the center frequency and first sideband respectively while the maximum power level at the higher sidebands are suppressed significantly by optimizing the periodical on-off switching instants of the antenna elements by using fire-fly algorithm (FA). The FA optimized pattern as realized in MATLAB platform is validated by designing the uniformly excited time modulated linear array (UE-TMLA) in CST-MWS with the same on-time sequence as obtained by using FA and the patterns are compared.